CA2374576C

CA2374576C - Multi-purpose aircraft

Info

Publication number: CA2374576C
Application number: CA002374576A
Authority: CA
Inventors: David E. Gevers
Original assignee: Individual
Current assignee: Individual
Priority date: 1993-08-26
Filing date: 1994-08-24
Publication date: 2005-10-18
Anticipated expiration: 2014-08-24
Also published as: CA2374576A1

Abstract

Several innovative systems for an aircraft, and aircraft incorporating them, are disclosed. Features include inboard-mounted engine(s) (24, 25) with a belt drive system (84, 99) for turning wing-situated propellers (8, 9);
compound landing gear integrating ski (29, 114), pontoon and wheel (18, 19, 21) subcomponents; pivotal mounting armatures (6, 7) for landing gear and/or propellers which provide a plurality of possible landing gear and/or propeller configurations; and a compound wing structure (14, 15) featuring extendable wing panels (4, 5) that permit the wing span of the aircraft to be nearly doubled while in flight.
Aircraft incorporating such features will enjoy several safety advantages over conventional multi-engine aircraft and will be capable of modifications during flight which permit landings on any of snow, hard surfaces (runways) and water.

Description

MULTI-PURPOSfi AIRCRAFT
Technical Field The presort im~endon relates to general aviation aircraft. More particularly, the present invention relates oo a novel aircraft adaptable to recreational, utility, or business uses and disdaguished by design features permitting fuselage expansion a~ in-flight alteration of its configuration.
Background Art Many different types of aircraft have bees desig~d to melt, within the limits of airworthiness, the particular requiremenrs of fliers. Thus, aircraft designs and design modifications are well known which wiD permit aircraft to land on different surfaces, such as ski-type landing gear for lardungs on snow, hull-type fuselage and pontoons for amphibious landings. and wing designs having inct~sed wing sur6ce areas and shapes for takeoff and landing in short distances. Stroukoff, for instance. described in U.S. 2.844,339 retractable sld landing gear added to as aircraft having renxtiag tricycle wheel gear, however the added slti components were not integrated with the wheel gear and did not lend the capability of coordinated movement, to meet the demands of a variety of landing surlaca.
Some f~au~es have also been developed that pemvit modification of err aircraft's configuration 2 0 (and thus its flight charactctistics) while in flight. For example, some jet fighter aircraft are often equipped with wing panels that are rotated out from the fuselage to increase wing span and lower stall spud for takeoffs and landings but are swept back during flight to increase ma~ttvenbility and decrease drag and bending stresses.
Although the adaptability of an aircraft to differcat uses and to different flight and landing 2 5 conditions is always desirable, most design modifications that shit as aircraft to a particular spaialized use necessitate design compromises that adversely affect the sirrraft's performance in some other aspect. For instance, amphibious aircraft designs have been limited by the necessity of placing the engine high over the wing, to avoid ianerference with the propeller by the spray of waoer from takeoff or landing. This is a design compromise that crates a high thrust lip for the aircraft gad also additional drag.

3 0 Also, the sign sopbistication and sa~mral reqturemeats necessary to adopt such capabiyities as 'swing" wings are umpractical and expensive for private rxreatioml aircraft.
Accordingly, there is a continuing need for the development of aircraft that are suited to a variety of uses gad which can satisfy the requirements and damands of a wide variety of commercial and recreational fliers.

a is as object of the present invention, therefore, to provide a novel twin-engine propeller-driven aircraft (although many feadires of this invention will be applicable to jet-powered aircraft and to aircraft having any number of engines).
It is a further object of the present invention to provide a basic aircraft design that can be adapted to serve a wide variety of specialized uses without entailing modification of the design or extensive refitting.
It is a further object of the present invernion to provide a basic aircraft design capable of a wide range of uses but without imroducing design compromises that limit or reducx specific flight performance characteristics.
It is a further object of the present invention to provide an aircraft capable of landing on snow, water or land without pre-flight modific~ion of the laadiag gear.
It is a further object of the present invention to provide a short takeoff sad landing (STOL) aircraft having a high degree of maneuverability and capabk of trimming drag and decreasing wing surface area sad wing span in flight.
It is a further objax of the present iron to provi~ a beak design for an aircraft that is expandable from 2 seats to 8 or more seats without entailing redesign of the airfoil or fuselage.
It is a further object of the present invention to provide a basic design for an aircraft 2 0 chat is convertibk fra~m a passenger-carrying configuration to a eargo~eawying configuration (or to other spxialized cabin configurations) without entailing redesign of the airfoil or fuselage.
it is a further objax of the present invention to provide a novel landing gear design integrating skin. w6eela, and pantoo~, which can be converted to the appropriate configuration during flight.
2 5 It is a further object of the present inveadon to provide a propellor-driven, mufti-engine airtxaR with improved safety cltuameriatics. Ia particular, it is an object of the invention to provide >iraaft of unprxed~ safety through an aircraft design which eliminates many of the leading causes of aviad~ accidents. including asymmetrical thrust c~ditioos due to an engine failure, propeller blade separation (i.e., loss of a propeller due to damage to the propelkr blades 3 0 and rive reaultirtg vibration and breakage), rapid power lose (engine failure) during takeoff or climbovt, inappropriate configuration or selation of landing gear. and accidents related to the position of the propeller on an aircraft on the ground (e.g., uniatatciooal eoatxxs with ground objats or people).
It is a further objat of the present invention to provide a novel propeller drive system 3 5 for a propeller-driven aircraft and to provide an aircraft design characterized by unifying mounting structures for the propellers and landing gear, allowing adjustment of propeller position relative to the airfoil as a function of landing configuration of the aircraft.
It is a further object of the present invention to provide a 2-8 seat aircraft that is easy to service and maintain and which maintains airworthiness in a variety of emergency situations.
These and other objects are accomplished herein by a novel type of aircraft and novel components thereof having a l0 number of innovative design features including: telescoping wing extensions; integrated multiple landing gear mounts permitting skis, wheels, or pontoon outriggers to be rotated into landing position, at the option of the pilot; modular fuselage sections permitting the addition of seats or cargo area without requiring redesign or refitting of wing or tail components; propellers mounted on their own shafts which are belt-driven from inboard engines; a primary structure permitting support of the engine mass by the fuselage structures rather than the wings and permitting large fuselage openings for easy engine access, efficient cargo handling, enhanced pilot visibility, or enhanced passenger comfort.
Utilization of one or more of these features provides an aircraft of improved safety, performance, reliability, efficiency, and versatility over aircraft currently available.
One broad aspect of the invention provides an aircraft capable of takeoff from and landing on snow or a hard surface, comprising: a wing structure; a fuselage (300); a forward landing gear assembly moveable relative to said fuselage (300) during flight from a first position retracted within said fuselage (300) to a second position extended from said fuselage (300), said forward landing gear assembly comprising a steerable forward wheel assembly (21, 193, 203, 230, 316) and a steerable forward ski assembly (29, 193, 203, 230, 316), said forward - 3a -landing gear assembly further comprising a forward landing gear actuator assembly (191, 197, 198, 201, 204, 205) operable by the pilot of the aircraft during flight which selectively deploys said steerable forward wheel assembly (21, 193, 203, 230, 316) or said steerable forward ski assembly (29, 193, 203, 230, 316) to said extended second position for landing, said forward landing gear actuator assembly comprising a positioning assembly (190, 197, 198, 201, 230) for deploying and retracting said forward wheel assembly and said forward ski assembly relative to l0 said fuselage (300), a ski deployment actuator assembly (204, 205, 206, 207, 208, 209) for positioning the forward ski gear assembly relative to the forward wheel assembly, whereby control of the extension of said ski deployment actuator assembly determines whether the forward ski gear or the forward wheel assembly is in the appropriate position to contact the ground upon landing; and a main landing gear assembly moveable relative to said fuselage (300) during flight from a first position retracted within said fuselage (300) to a second position extended from said fuselage (300), said main landing gear assembly comprising a steerable main wheel gear assembly (20, 133, 210, 220) and a main ski gear assembly (137, 144, 145, 147, 149) including a pair of skis (147), said main landing gear assembly further comprising a main landing gear actuator assembly (130, 137, 138, 141, 215, 216) operable by the pilot of the aircraft during flight which selectively deploys said steerable main wheel gear assembly (20, 133, 210, 220), or said main ski gear assembly (137, 144, 145, 147, 149) relative to said main wheel gear assembly, said main landing gear actuator assembly comprising a main gear connecting link (137), forward and rear ski supports (144, 145) carrying said main ski gear assembly pivotally attached to said main gear connecting link (137), forward and rear positioning actuators (216, 215) for pivoting said forward and rear ski supports relative to said main gear connecting link (137), and a main gear mounting assembly (210, 220) pivotable relative to said main gear connecting link (137), permitting said main wheel gear assembly ' CA 02374576 2004-07-09 - 3b -to move relative to said main gear connecting link, whereby control of the extent of deployment by said main landing gear actuator assembly determines whether the steerable main wheel gear or the main ski gear assemblies are in the appropriate position to contact the ground upon landing;
wherein said main landing gear assembly in said first position forms an integral part of said fuselage (300) with said main ski gear assembly forming the exterior surface thereof, said pair of skis of said main ski gear assembly in said retracted position forming a substantially flush surface with said fuselage (300) .
According to another broad aspect, the invention provides a compound aircraft wing comprising: a fixed wing section comprising a bilaterally symmetrical aircraft wing of a fixed length (span) defining leading and trailing edges and defining port and starboard halves, said fixed wing section being at least partially hollow, thereby defining an inner surface and an outer surface of said fixed wing section, said fixed wing section further being open at the port and starboard ends, thus forming port and starboard openings, a port wing extension panel comprising a forward port lift spar, a center port drag spar, and an aft port lift spar, which port spars are disposed in parallel relation and each spar being substantially the same length as said fixed wing section, substantially one-half the length of said spars being enclosed by and giving structural support to an outer skin so as to form a port aircraft wing extension section ending in a wing tip, said port wing extension panel being extendably mounted inside said fixed wing section such that said port wing extension panel is extendable through the port opening of the fixed wing section such that substantially all of the port aircraft wing extension section protrudes from the port end of the ' CA 02374576 2004-07-09 - 3c -fixed wing section, said port wing extension panel further being mounted inside said fixed wing section such that said port wing extension panel is retractable within said fixed wing section such that substantially all of the port wing extension panel is enclosed by said fixed wing section, and a starboard wing extension panel comprising a forward starboard lift spar, a center starboard drag spar, and an aft starboard lift spar, which starboard spars are disposed in parallel relation and each spar being substantially the same length as said fixed wing section, substantially one-half the length of said spars being enclosed by and giving structural support to an outer skin so as to form a starboard aircraft wing extension section ending in a wing tip, said starboard wing extension panel being extendably mounted inside said fixed wing section such that said starboard wing extension panel is extendable from the starboard opening of the fixed wing section such that substantially all of the starboard aircraft wing extension section protrudes from the starboard end of the fixed wing section, said starboard wing extension panel further being mounted inside said fixed wing section such that said starboard wing extension panel is retractable within said fixed wing section such that substantially all of the starboard wing extension panel is enclosed by said fixed wing section, said port wing extension panel and said starboard wing extension panel being mounted in such relation that said port spars and said starboard spars are in interlocking juxtaposition inside the fixed wing section.
Brief Description of the Drawinqs Figure 1 is a perspective view of an aircraft according to the present invention, showing telescoping wing sections and landing gear fully extended. The aircraft is - 3d -shown in a configuration advantageous for takeoff and landing on a hard surface.
Figure 2 is a perspective view of an aircraft according to the present invention as illustrated in Figure 1 but with an alternative, conventional tail design (as opposed to the "T" tail shown in Figure 1).
Figure 3 is a perspective view of an aircraft according to the present invention, with the propeller mounts and landing gear retracted. The aircraft is shown shortly after takeoff or in a configuration suitable for low-speed flight.
Figure 4 is a perspective view of an aircraft according to this invention as depicted in Figure 3, showing telescoping wing sections in a fully retracted position.
Figure 5 is a perspective view of an aircraft according to this invention as depicted in Figure 4, except that a modular fuselage section has been removed to attain a shorter fuselage.
Figure 6 is a front elevation view of an aircraft according to the invention, shown in the hard surface takeoff and landing configuration similar to Figure 1.
Figure 7 is a front elevation view of the aircraft as illustrated in Figure 6, but with telescoping wing panels in a fully retracted position.
Figure 8 is a front elevation view of an aircraft according to the invention, shown in the configuration appropriate for takeoff or landing on snow or ice Figure 9 is a front elevuion view of as aircraft according to the invetuioa, shown in a configuration appropriate for taheo" .~r landing on wiser.
Figure 10 is a front elevation view of an aircraft as depicted in Figure 9, in a configuration appropriate for slow speed water taxiing operation.
Figure 11 is a front elevation view of as aircraft according to the invention, shown in a high speed cruise configuration. This is the same configuration as depicted in Figures 4 and 5.
Figure 12 is a front elevation view of.an aircraft as depicted is Figure 11, shown in a low speed configuration. ~ telescoping wing sections fully extended. This is the same overall cottfiguruion for the aircraft as illustrated in Figure 4.
Figure 13 is a plan view of an aircraft as depicted in Figures 3 and 12.
Figure 14 is a plan view of an aircraft as depicted in Figures 1, 6, and 8.
Figure 15 is a plan view of an aircraft as depicted is Figures 4 and 11.
Figure 16 is a perspective view of the sta:boar~d wing extension assembly of a compound wing structure according to the present invention. This figure shows the internal supporting beam structures of the extendable wing satin.
Figure 17 is a detail of the encircled portion XVII of Figure 16, showing the inboard end of the supporting spars of the extendabk wing section.
Figure 18 is a perspaxive view of t~ starboard wing exteoaion assembly as depicted in Figure 16, showing its position relative to the main wing section (shown in phantom lines) when 2 0 the wing extension panel is fully exa:nded (ref. Figure 13). Thin figure also shows the positioning of roller assemblies enabling rolling extension of the wing extension pawls and shows the relative position of the support strutxures of a port wing extension assembly.
Figure 19 is a detail of the encircled portion XDC of Figure 18, showing th a positioning of rollers in reluion to the supporting spars for the eatendabk wing section.
2 5 Figure 20 is a paapative view of the starboard wing extrusion assea>bly as depicted in Figure 15, showing its position relative to the main wing section (shown in phantom litres) when the exteaaion patrol is fully raraaed (ref. Figure 15).
Figures 21, 22, wad 23 show front cross-sectional views of the starboard wing lift spars and supporting rollers in fully extended (Figure 21), ina:rmediate (Figure 22), wad fully 3 0 retracted (Figure 23) cmtfiguratioos.
Figure 24 is a cross-sectiottai view of a wing extension panel talrta on the line A-A in-Figure 13.
Figure 25 shown a cross-sectional view of a wing taken on the line H-B in Figure 13.
Figure 26 shows a cross-sectional view of a wing on the tine C-C in Figure 15.

Figure 27 is a perspective view of the supporting lift and drag spars of a starboard wing extension assembly according to the invention, showing the interlocking relationship of lift a~
drag spare of~a pori wing extension assembly and also showing a preferred cable menhanism useful for extending and retracting the extendable wing sections. The arrows indicate direction of motion during wing rea~ion.
Figure 28 is an enlarged derail of encircled portion XXViZI of Figure 27.
Figure 29 is a perspecxive view of starboard wing support structures similar to Figure 27, showing as alternuive screw-type mechanism for extending and retracting the wing extension panels.
Figures 30 and 31 are cross-sectional views of a wing takes on line J-J of Figure I5.
showing a preferred mechanism for coordinsted acaration of the ailerons on the feed wing section and on the wing extension panel. The componems of Figures 30 and 31 are exactly cta:
same: the two figures show simultan~us adjustment of the positions of the fixed wing aikmn ( 10) and the extension panel aileron ( 12) relative to the atuionary surfacx of the wing (2) as the ailerons are trimmed from a raised position (Figure 30) to a lowered position (Figure 31).
Figure 32 shows the preferred design for acwuion of the ailerons using a cable system for the extension aikroas (12) and a~puah-pull rod system for the fixed wing sxtioa flap (72) . and aileron (10).
Figure 33 is a perspcaive diagrammatic view of an aliernace design for the actuation of 2 0 the aileron systems of an aircraft acxording to the invention. In contrast to the acarad~ system depicted in Figure 30, this figure shows a cable system for xarating herb the flaps (72) and ailerons (10) of the fixed wing section and the ailerons (12) of the wing extension assembly.
Figure 34 is a cross-rational view of the fuselage taken on line I-I in Figtue 15, showing chc relative positions of the powerpiants and the beh drive systrm in a preferred embodiment of this invend~. Air cooled aircraft engines are depicted.
Figure 35 is a trees-sectional from elevation of as sinxaft acxording to the invention showing the paaitioniqg of the engines in the fuselage, the belt and pulley system for driving the propellers, and the pivotally mounted arntaatra providing pivoting mourns for both the landing gear and the propellers. The compo>Kms depicted in this figure ue shown in a configuratiofl 3 0 typical of in-flight operation (cf. Figure 4), with landing gear rettatxed into the fuselage.
Figure 36 is a schematic plan view looking down ~ a compound wing aweture according to the invention and a prefi ~-red belt drive system for curnittg pusher-type propellers mounted in pivoting armature mounts according to the invention. The drawing shows the relative positions of the port wing extension panel (5) and the starboard wing exteeuion parcel 3 5 (4) ituide the fixed wing section ( 1 ). Also visible in this schematic view are strucattal compone~ of tlx; wing extension panels, i.e., front (31) and rear (33) lift spars of the port wing extension assembly and port drag spar (35) (diagonal lines), as well as the starboard front (30) and rear (32) lift spars and drag spar (34) (cross-hatched) of the starboard wing extension assembly. The wing extension panels are shown partly extended, and the inoerlocting juxtaposition of the supporting spars (30, 31. 32, 33. 34, 3~ within the fated wing structure (1) is also shown. Also illustrated in Figure 36 is a preferred arrangement of port (diagonal lines) and starboard (cross-hatched) drive belts (84, 99) for actuating port and starboard propellers (9 sad 8, respectively) via propeller drive shafts (81).
Figure 37 is a side elevation of the engines and drive belt system disclosed herein, showing details of the gear box (110) of Figure 34.
Figure 38 is a perspective view of starboard sad port curved mounaag armatures and mounted propellers, shown in isolation from the aircraft (cf. Figure 4) but in proper relation to each other. The armatures are shovm in the relative positioat they would have, e.g.. in an aircraft as depicted in Figure 4, wherein the propeller centers are in line with the planes of nhe wings and the landing gear are fully retraced imide the fuselage.
Figure 39 is a frontal diagram of two pivotal mounting armatures in the same relation as depicted in Figure 38, provided to indicate the preferred shape and dimeaaioos of such Figure 40 shows a cross-sectional view of a wing taken on the line D-D of Figure 15.
2 0 Figure 41 is a perspective view of starboard and port curved mounting armatures and mounted propellers, shown in isolation from the airaaft (cf. Figure 8. Figure 5'n but in proper relation to each other. The armatures are shown in their relative positions, e.g., in an aircraft as depicted in Figure 1, wherein the propellers are positioned above the surface of wings and caster-type wheel gear are deployed, as appropriate for a runway landing.
2 5 Figure 42 is a perspaxive view of starboard and port curved mounting armatures and mounted propellers, shown in isolation from the aircraft (cf. Figure 9) but in proper relation to tech other. The armature: are shown in their relative positions, e.g., is an aircraft as depicted in Figure 9, wherein the propellers are raised to their maximum distance above the wings and the pontoon gee are fully deployed. as apprvprim for a water landing.
3 0 Figure 43 is a cross-sectional view of a wing taken on the line E-E of Figure 14, showing the relative position of the propeller mounting to the wing when the aircraft is in a talceoffllanding configuration as depicted in Figures 1. 6, and 8. In a cutaway, the relationship between the propeller, propeller shaft and propeller drive belt is shown.

_7_ Figure 44 is a cross-saxional diagTammadc view of the forward fuselage of an aircraft of the invention, taken on line F-F in Figure 11, showing the structures of a focwud landing gear component of the compound landing gear in a fully retracted configuration.
Figure 45 is a similar forwud cross-secdo~nal view to Figure 44, except that the forwud Landing gear are shown partially extended.
Figure 46 is a simile cross-sectional view to Figure 44, except the forwud landing gee are shown fully extended (uncompressed). in a configuration typical of the instant before landing or the instant after takeoff.
Figure 47 is a simile cross-sectional view to Figure 44, except the the forward landing gee are shown extended and fully compressed. in a configuration typical of a high-impact landing on a hud surface.
Figure 48 is a simile forward cross-sectional view to Figure 44, extxpt that the forward landing gee are shown fully extended to support the weight of the nose of the aircraft and in a configuration appropriate to taxiing.
Figure 49 is a simile cross-sectional view to Figure 44, except that the skis of the compound forwud landing gee ue shown fully extended, in a configuration appropriate to landing on a snowy or icy surface.
Figure 50 is a cross-sectional diagrammatic view of the cena~al portion of the fuselage of an aircraft according to the invention, taken ~ line F-F of Figure 11. The outer fuselage panels 2 0 that enclose the main central landing gear component of a compound landing gee are shown in the proper in-flight position, forming an aerodynamically smooth outer surface.
Figure 51 is a cross-sectional view simile to Figure 50, except the outer fuselage panels are shown by phantom lines in order to expose the struc:itra of the main central landing gee.
The componems of a preFerred main central landing gee according to the invention are shown.
2 5 fully folded and enclosed within the fuselage, i.e., in their fully raratxed and stowed position appropriate during flight. The relative positions of the inboard engines (shorvn in silhouette) and beh drive mechanisms, landing gear, primary fuselage structure, wing structure. attd wing extension assemblies are shown in this figure.
Figure 52 is a perspective elevation of a preferred main cena~a! landing gear assembly, 3 0 shown in a fully revaeued configuration, as the asxmbly wou~ be positioned in flight. In such configuration, the lower surface of the skis would form part of the aura surface of the aircraft's fuselage; the rest of the landing gee assembly would be inside the fuselage of the aircraft, out of the airstream.
Figure 53 is a perspative elevation of a preferred main central landing gear component 3 5 of the compound landing gee of the invention. The assembly shown unifies central wheel-typr $_ landing gear (not visible in this view), ski-type landing gear a~ flotation-assisting hollow design ski snots. The assembly is shown in a deployed configuration that places tlu wheel-type landing gear in a vertical position suitable for use in landing on a hard surfacx or runway. (Cf.
Figure 54.) In this position tl~ skis are semi-deployed and will not meet the surface during a normallaoding.
Figure 54 is a cross-scaional view of the midsection of the fuselage of an aircraft according to the invention, taken on line P-P of Figure 7 and depicting the compound landing gear depioyod so as to make use of the wheelod gear, i.e., in the configuration most suitable for Landing on, taking off from, and taxiing on a hard surface.
Figure 55 is a cross-sectional view of the midsection of the fuselage of an aircraft according to the invention, illustrating compound landing gear deployed so as to make use of the main ski loading gear, i.e., in the configuration most suitable for landing on, tasting off from. and taxiing on a snow-covered surface.
Figure 56 is a cross-sectional front elevation of the midsection of the aircraft as illustracsd in Figure 54, showing strucarres of the main oemral and stabilizing landing gear components in the configuration appropriate to takeoff and landing or taxiing on hard surface runways. (Cf. Figure 7.) Several strucatral elemea~ not related to the ia~ing gear are omitted . . . from this view.
Figure 57 is a crass-satiooal fret elevation of the midaecaoa of the aircraft simile to the configuration depicxed in Figure 56, except that the deployment of the landing gear has been modified as appropriate for takeoff sad larding on intermittent snow over a hard surfacx runway. Several suvctural elemema not related to lading gear are omitted from this view.
Figure 58 is a cross-axaonal front elevation of the midsecrion of the aircraft as illustrated in Figure 56. showing swctures of the main centre! landing gear and stabilizing 2 S landing gear compouencs in the configuration appropriate for takeoff and loading on snow. (Cf.
Figure 8.) Several st:ucwral ekanena not related to landing gear are omimed from thin view.
Figure 59 is a doss-sectional front elevation of the midsection of the aircraft similar to the configuration depicted in Figure 56, with main ~aral landing gear rara~ed, showing the mvuruiag armatures (6 std 'n, and thus the pontoon subcompooems (22 and 23) fully deployed.
3 0 i.e., in the configuration appropriate to takeoff and landing oo water.
(Cf. Figure 9.) Several swcarral elements rrot related to landing gear are omitted from this view.
Figures 60 and 61 show schematic illustrations of steering mechanisms for aircraft of this invemion. Figure 60 shows a preferred staring control system, in which control of the trout and rear wheels are linked such that turning the rear (main) gear simultaaeousiy turns the 3 5 nose landing gear.

_g.
Figure 61 illusu~ates a similar steering control system in which the nose gad main geu are controlled tadependetlttly.
Figure 62 is an eapioded perspective view of an aircraft according to the invention showing the modulu components of t~ fuselage and major components of the aircraft.
Alternative wide-fuselage cugo-type components (231 and 232) to the standard passenger-type upper fuselage componems (3 and 2) are also shown.
Figure 63 shows a plan view of a wide-fuselage embodiment of the invention.
This fuselage option can be compared to the standard fuselage configuration shown in Figure 15.
Best ode for Curving Out the lm~ention Preferred embodiments of the present invention will be described below with reference to the drawings. It will be immediately appraiated, however, that the design features described may be altered or modified for parriculu purposes gad that the production of many alternative embodiments of the aircraft described herein will be possible in view of this dixlosure. A11 such alterations. modifications and additional embodiments are contemplated herein and ue intended to fall within the scope of this description and the appended claims.
The following description is not intended to limit the scope of the invention in any way.
Preferred embodiments of a complete aircraft according to the present invention ue shown-in various configuruioas and views in Figures 1, 2, 3. 4, 5. 6, 8, 9, 10, 11, 12. 13, 14, 15 and 62. The preferred features of the aircraft include compound wings comprising a fined 2 0 wing section also housing port and stuboud ext~endabk wing panels, which can be deployed (in-flight, if desired) to increase wing surface area and lift; pivoting mounting armatures that serve as propeller mounts and also as aft loading geu mrnuaa, the armatures serving to change simultaneously the position of the propellers and the compound landing geu with respecx to the rest of the aircraft, i.e., placing the propellers in the optimal position for landing on or caring 2 5 off from a variety of surfaces or for cruising flight, such positioning of the propellers occurring auwmaticaiiy as c~pound landing geu mounted on the armuurcs are rotated to expose the appropriate type of landing geu (wheeled geu, sris, pontooaa) for different loading surfaces (tu~c. scow. water) or are rotated to nest is recesses in the fuselage of the aircraft during flight; modulu fuselage design permitting augmentation of the aircraft in production to meet 3 0 different pasxager~arryit~ or cu8o.carrying txeds without re-design;
elimination of an aft fuselage saxion and a stronger, more cosily fabricated tail satioa; gad a power train featuring inboard engine mounting (preferably twin, taademly mounted and opposed engines) gad a novel belt drive for propellers.
Referring to Figure 1, an aircraft according to the invention cad featuring several design 3 5 innovations is illustrated. The overall configuration of this embodimetu is of a cantilever high-wing, amphibious monoplane, preferably having a hull-bosomed fuselage and twin rear-facing, pusher-type Propellers.
Tlu; wings are compound in structure, comprising a main wing section (1) fixed to the main fuselage structure (300), port and starboard leading edge slats ( 15 and 14, rapatively), and port and starboard main ailerons (11 and 10, respectively). The main fuselage section includes an aft tail section (310), shown in Figure t a a cantilever T tail, with steering surfxes including a rudder (311) and an elevator (312). The primary aikroos 10 and 11 of the fixed main wing section ( 1 ) are aerodynamically shaped surfaces on the trailing edges of the wing section and are used for control of the aircraft motion around the longitudinal axis (roll control), primarily at high speeds. The main wing section (1) also houses two telescoping extendable wing sections (4 and 5), which can be extended (picaued) or fully retracted within the main wing section (1), as illustrated in Figures 4. 11 and 20. The extendable wing sections (port. 5;
starboard, 4) also have leading edge slats (port, 17; starboard, 16) and aikrona (poet, 13; .~
starboard. 12), as on the main wing section (1). The leading edge slats (14 acid IS) of the fixed wing saxion ( 1 ) are (preferably) focwardiy extendable to change the lift characteristics of the compound wing, and the ailerons (10-13) are trimmed to steer the aircraft in flight. Preferably the port main wing aileron (11) and the port exteruion panel aileron (13) are actuated by the same or connxced mechanisms, and the starboard main wing saxion aileron ( 10) and the starboard extension panel aileron (12) are similarly co-xwated, so that the movements of both sets of ailerons are complaely coordinated and may be effaood without using multiple controls.
Likewise, it is preferred that the leading edge slats ( 14 and 15) ate co-acasated, so that their operation is coordinated and requires manipulation of a minimum mamba of com~rola.
In most preferred embodiments, the compound main wing setxion (I) futtha includes rep for acxxpting pivoting propeller mounts (6, ~, which may be rotated to raise the ., 2 5 propelkra above the level of the wing (preferable f~ water landings) or to nest the propeller mourns in recesses in the wing (see. Figures 3-5) to bring the propellers eves with the wing surface (ptrfaabk for climbout and cruising flight).
The compound wing structure described herein lends aevua! advann~a to an aircraft.
When the extendable wing panels (4, 5) are fully retracted and thus completely housed within 3 0 the fixed main wing section ( 1 ), out of the airstream, the wing span of the aircraft is considerably shortened (e.g., reduced almost 50°J6), giving the aircraft inerebed maneuverability and higher cross-wind stability. The ability to retract the wing panels (4, 5) and thereby significantly reduce the wing span leads to improved safety chara~cxeristics for the aircraft in that the wing bending stresses in the cruise and maneuvering configurations (see.
35 Figures 4 and 5) are reduced. Wing stresses are also reduced by the interlocking juxtapositiun of the supporting spars (discussed. ice; ref. Figure 36) of the eauadabk wing sections. when the wing seaiona are fully raracted. The interlocking support spar design also makes it posaibk to increase the wing span up to 90-9596 while maintaining the stru~ural integrity a~
operability of the wing, a capability that was not attainable with previous designs.
The ability to extend the extendable wing sections (4, 5) while in flight makes aircraft according to the present invention ideal for pilot training by providing the capability of simulating t~ flying characteristics of a wide variety of aircraft. When the extension panels are reaacted, the aircraft has spend, maneuverability and wing stress-beuing characteristics similar to xrobatic or military combat aircraft; when the wing extension panels are fully extended. the aircraft simulates the lower stall speed, greater lift and high altitude flying characterisdes of STOL, commuter and patrol aircraft; and with intertxdiate, variable extension of the telescoping wing extension panels, flight characteristics can be varied to match those of other types of aircraft or to tailor the aircraft's properties in-flight to meet changing air and wind conditions, or to prepare for landing on or takeoff from a variay of diffecenc surfaces.
The retractable wing section feature also make the aircraft of this design suitable for full-scale aerodynamic testing of new airfoil sbapa in-flight. For example, new airfoil designs may be fitted to the aircraft as extendable wing seaiona (4, ~. gradually and safely extended while the aircraft is in flight, and rearacted out of the airstream if undesirable characteristics are decaxcd.
2 0 Additional advacuages provided by the telescoping wing feadtra include improved safety in cond'ttioas of ice accumulation on the wings by virwe of the ability to retract a major portion of the wing during ice accumulation and extend said wing sections (free of ice) during landing. The aircraft tray also convert from a relatively long wing span that is advantageous for takeoff and loading, fuel efficient long range flight, and high altitude flight to a shorter wing 2 S span that is effici~t for high speed flight and advatuageous for storage and operation around .
obxaclea (such as other aircraft) on the ground or in underdeck stooge on a ship. This wing design also providd high wing loading (weight per wing area) during cruise (retracted wing paoela). which gives pilot and passengers a relatively smooth ride through turbulent air. and a low wing loading (euaded wing panels) during takeoff and landing to provide an improved 3 0 operational safety margin at low airspeeds (greater lift, lower stall speeds) and lower landing speeds, resuhing in a reduced potential for damage or injury in landing axide~. This wing design also provides a meam of expanding wing surface area for carrying larger payloads or a larger quantity of fuel for long trips, or a means of reducing wing surface area for more efficient cruising flight with minimum payloads or low fuel.

Referring again to Figure 1, the fixod main wing section ( 1) and an optional fuselage extension module and cabin extension assembly (2) are fixedly attached to tlk main fuselage section (300). -An upper cockpit assembly (3), attached to a forward cabin module (233 in Figure 62) that houses the forward landing gear (e.g., 21 and 29), is attached et~-to-end to an upper cabin extension assembly (2) and a cabin extension module (234 in Figure 62), to provide a continuous enclosed cockpit and cabin area forward of the main fuselage sxtion (300).
Alternatively, as picdued in Figure 5, the forward cabin module and the upper cocrpit assembly (3) may be attached end-to-end to the main fuselage section (300), e.g., where no additional cabin/cargo spact or a smaller, lighter weight aircraft is desired. The nose assembly (3), any fuselage extensions (2), and the male fuselage saxion (300) toget~r comprise the fuselage and tail of the aircraft as a whole.
The front landing gear are comprised of elements such as the front wheel (21) aztd the froze sitis (29) and may be mounted in and attached to the forward section of tlx fuselage through support and exteosionlretraction members explained in more detail jpøg.
The wing extension panels (4 and 5) are mouztted inside the fixed wing ration (1) so as to be simultanea~usly exteztdable laterally out from the starboard and port wing tips (38 and 39, respectively) or simultaneously retractable into the fixed wing sectia~n (1).
When fully tetraaad.
. . the extension panels (4 and 5) are completely enclosed within the fixed wing section ( 1 ) of the aircraft. and the exteztsion panel wing tips (36 and 37) meet azid preferably nest into the fixod wing tips (38 and 39) to form an aerodynamic teardrop wing tip. (See, e.g., Figures 4 and 7.) The embodimetu of Figure 1 also shows curved mounting armatures (6 and 7) which are pivotally attached to the rear of the fixed wing section (1), near the fuselage. The armatures (6 attd 7) not only provide a mount for the pz~opelleza (8 and 9) but also provide a mount for rear stabilizer landing wheels (19 and 20) and flotatiozzal poe><oon assemblies (22 (not visible in this Z5 figure) std 23), which serve as outrigger-like stabilizers during amphibious operations. The mourning armatures (6 and 7) are generally pan-shaped when viewed edge-on (see. e.g.. Figure 5 and other front elevation), and the curvature of the umaarres permits the pilot to bring the wheeled landing gear ( 19 and 20) or aleernatively the pontoon landing gear (22 and 23) into position for use by causing the arznaturea to rotate about their pivotal attachment. Additionally.
3 0 because the armadtra (6 and 7) also serve as a mount for the propellers (8 sad 9), raacing the desired landing gear (wheels or pontoons) into position for use simultaneously will change the posidozts of the propellers relative to the wing and fuselage. The armatures are shaped so that at the maximum rotation of the lower end of each armswre away from the fuselage of the aircraft. that is, to expose the pontoon landing gear (22 and 23). the propellers simultaneously 3 5 are rotated away from and above the wing, toward the centerline of the aircraft, so that the 7?316-13D

propellers are raised to a maximum height above the water and are shielded fmot water spray by the wingi nerd fuselage. (See, Figure 9.) The mounting armatures (6 and ?) are preferably designed so that the entire propelkr can be raised above the surface of the wing when a water landing is auempted.
Water spray damages propelkrs: water droplets can cause pitting of the propeller blades, the tips of which are moving at near-sonic speeds. In conventional amphibious aircraft designs, at least the lower arc of the propeller is often exposed to water spray, but in preferred embodiments of this invention, the mounting armawres will cause the entire arc of the propeller to be shielded from water spray by the wiagi, when the propelkcs are positioned for a water landing. For hard surface landings. also, the armatures (6 sad ~ will position the propellers above the wing, where the propellers are much less likely to contact objects oa the ground or.
to come into contxt with people moving around the aircraft.
In the most preferred embodiments, the armarures (6 sad ?) are additionally shaped to nest in recesses of the wings directly above the flaps (72. actually split flaps, only a fracdoa of the thickness of the wing) and on either side of tlae fuselage (305), when the armatures are pivoted to align the propellers with the surface of the wing and to r~ra~x the landing gear. This means that below the pivot point, the ~outtr surfaces of the armatures (6 and T) when fully rotated will become flush with the surface of the main fuxlage section (300):
sad above the pivot point, the outer surface of the armatures (6 and ?) when fully rotated will be flush with 2 0 and biome part of the aerodynamic surface of the fixed wing section ( 1 ).
.
Recognising that many modifications sad alternative choices of design or materials are possible from the deseripti~ herein, a moat preferred embodiment contemplated f~ the present invention will have the genersl coafiguratioa depicted in Figure 1 with the following dimensions:
2 5 center (fixed) wing aectioo ( 1 is Fig. 1 ): NACA 66~-018 at root acrd tip, dihedral 3 degrees, swap -3.28 degrees (forward) at the a chord, with two imeraally mouatad telescoping wing exteaaioa panels, 0 degrees swap;
wing span (panels fully retracted): 26 feet (7.92 meters):
wing span (paneia fully extended): 50 fen ( 15.24 meters. 92.31 ~6 increase over fully 3 0 rara~d):
wing chord at feed root: 10 fen. 8 i>xbes (3.25 meters):
wing chord at feed tip: 6 fat. 8 inches (2.03 niters);
wing chord at extension root: 3 feet. 8 inches ( 1.12 meters):
wing chord a excetuion tip: 3 feet. 8 iacdes ( 1.12 meters):
3 5 wing aspax rule (reaaaed) 3.125:

wing aspect ratio (extended) 8.33;
moveable leading edge slats on center wing suction, fixed leading edge slur on extension sections;
construction: ail wing sections preferably constructed of flush riveted aluminum;
cantilever T-type tail constructed of flush riveted aluminum, having a horizontal stabilizer and an elevator (optionally including servo-tabs);
tailplane span: 14 feet, 7 inches (4.44 meters);
lower fuselage: riveted aluminum for amphibious hull and main fuselage section (300 in Fig. 1);
upper fuselage (cabin): fiberglass composite;
fuselage construction: 3 sections (nose, center cabin, and main fuselage (engine enclosure) including tail section) bolted end-to-end;
overall length: 40 feet ( 12.19 meters);
overall height: 12 feet. 4 inches (3.75 meters);
wheelbase: 20 feet. 10 inches (6.35 ratters);
wheel trxk: 10 feet. 6 inches (3.2 meters);
propeller diameter: 6 feet. 6 inches (1.98 ).
Of course, the foregoing dimensions and preferred materials may be modified without departing from the concept of this invention, so long as the inventive fesntra, as recited in the claims, are incorporated.
Referring to Figure 2, an aircraft of the same general configuration as iliustratsd in Figure 1 is shown, except that an alternative tail section in the shape of an imrerted "T" is shown, equipped with a rudder (311) and a single elevator plane (312). All other features of this aircraft are as diaruased above for Figure 1. Mast prefetnd embodies of the invention 2 5 will have the T tail comiguration of Figure 1, wherein the tail surfaces are in the direct prop wash when the propelleta are raised above the wing and are out of the prop wash wheo the propellers are lowered to be level with the wing. This design lends maneuverability to the aircraft at lauding and takeoff speeds. when maneuverability is most critical.
Including various of the lnYenLlYe features of this invemion into as airecaft design 3 0 permits incorporation of a unique tail configuration, which is apparem is the embodiments of Figures 1 and 2. Inboard mounting of the engines is the aft portion of the fuselage, under and just aft of the wings (ref. Figure 51) makes the inciusioo of an fuselage section aft of the wings undesirable and impractical: therefore. the fuselage can advantageously begin to taper immediately aft of the wings to form a vertical tail section as shown. The tail ration can taper 3 5 in a straight line from the end of the fuselage, in contrast to conventional deigns including an aft fuselage, which leads to structural advantages in that stiffening stringers and such members are not bent or-made to follow contours and are thus able to withstand greater stresses. The horizontal stabilizer'piane and elevator of the tail arc supported by a much stronger and stifFer tail structure, and thus undesirable flutter of the tail control surfaces is eliminated. The S illustrated vercicat tail (Figure 1) is highly swept aft to balance aerodynamic forces, to reduce drag, to clear the propeller arcs at all propeller positions, etc., which leads to a tail section having a longer chord than normal. This also provides a very long vertical steering surface (rudder), which is believed to be unique to the present design. Modeling studies (discussed of the aircraft have indicated that the unusual span of the rudder does not dtaract from the performance of the aircraft or lead to undesirabk flying characxeristics.
Referring to Figure 3, the aircraft of Figure 1 is depicted in flight, with the wing extension panels (4 and 5) fully extended. The arc of the propellers (8 and 9 in Figure 1) is depieued by circles (labeled 8 and 9 here). The forward landing gear (i.e., 21 and 29 in Figure 1 ) are not visible in this figure, having been fully retracted into the nose section. Similarly, the curved mounting armatures (6 and 7) are picaued here pivoted to a position such that the rear landing gear (i.e., 19. 20 and 23 in Figure 1) are retracted and >toused within the fuselage section (300) under the wing, and the lower portion of the port armature (7) is sees to nest in the fuselage, flush with the outer surface of the main fuselage secxioo (300).
The upper portions of both curved mo<tnting armatures (6 and 7) are pictured here pivoted to a position such that 2 0 the mounted propellers (8 and 9) are a the level of the wing, and the armatures (6 and 7) are nesting in wing recesses such that the outer surfaces of the armatures (6 and 7) form flush, continuous surfaces with the surface of the main wing section (1). All other aspects of this figure are as depicted in Figure 1.
Referring to Figure 4, the aircraft of Figutts 1 and 2 is shown in flight, with the wing 2 5 extension panels (4 and 3 in Figure 1 ) fully retracted and housed within the main wing secti~
(1). In this configuration and in this port side perspective view, the only part of either wing cxteasi~ panel visible is the port wing extension panel tip (37). seen here mated with the port fixed wing tip (39) to form an aerodynamic teardrop wing tip. All other aspects of this figure are as depicted in Figure 3.
3 0 Referring to Figure 5, an aircraft substantially identical to the aircraft of Figures 1 and 4 is shown in flight, with the wing extension panels (4 and 5 in Figure I) fully raracoed and housed within the main wing section (1). In this configuration, the cabin extension module and upper cabin extetuion assembly (2) shown in previous figurrs have bees removed, resulting in a shorter fuselage and a decrease in overall aircraft weight. In embodiments of this invention 3 5 where (as here) the engines are mounted inboard, on the centerline of the aircraft and under the wings, modification of the fuselage in the manner illustrated t.aa be accommodated in the tttaaufacatring atep~ ~y. simply substituting lighter engines to redistribute the weight of the aircraft. No general redesign of the aircraft is naessary, and oo retooling of t>u manufacturing process must be done. As in Figure 4, the only part of either wing extension panel visible is the port wing extension panel tip (37), seen here mated with the port fixed wing tip (39) to form an aerodynamic teardrop wing tip. All other aspects of this figure are as depicted in Figure 4.
Referring to Figures 6 and 7, an aircraft axording to the invention is shown is fr~tal elevation, viewed none-on. The aircraft incorporates the compound wing assembly diacxtssed ~y~, comprising main wing struccure (1) and ulescoping extendable wing xctions (4 and 5).
As picaued, the fixed wing xcxioo ( 1 ) also comprises leading edge slats ( 14 and 15) and teardrop or bullet-shaped wing tips (38 and 39). The wing extension panels (4 and 5) are alto picatrcd with leading odge slats ( 16 and 17) and wing tip caps (36 and 37), which mate with the feed wing tips (38 and 39) to form aerodynamic teardrop wing tips, when the wing extension panels (4 and 5) are fully retracted within the fixed wing section (see. Fig.
7). Ailerons (10, 11) and flips (72) are also s6avn.
The aircraft illustrated in Figut~es 6 and 7 also incorporates curved mourning armatut~es (6 and 7), pivotally attached to the roots of the wings. each atmturtre comprising an upper std ' ' and a Tower end with raped to the pivotal attachment, the upper end of each armature being equipped and configured to accept a propeller asxmbly or to act as a propeller mount, and the 2 0 louver end of each armature being equipped and configured to acxxpt or to as as a mourn for a compound landing gear comprising stabilizing whxls (18 and 19) and pontoon members (22 and 23). Propeller: (8 and 9) are shown mounted on the upper ends of the arm~wres (6 and 7).
The position of the ends of the mounting armatures in relation to the fuselage of the aircraft (i.e., the degrx of rotaries about the pivotal attxhment) is preferably cotnrolled by mesas of 2 5 multilitat acting struts (280 and 281 ). Extension of the struts (280 sad 281 ) pivots the armaarres so that the upper end of each armature (6 and 7) and thus the propeller mounts are rotated upward from the level of the wing sad iawud toward the c~etline of the fuselage:
extetuioo of the struts (280 and 281) simultaneously pivots the armatura so that the lower end of each armature (6 and 7) and thus the compound landing gear ( 18, 19, 22, 23) art rotated 3 0 outward from the fuselage. At an intermediate point of extsosion (shown) of the acataciug struts (280 and 281). the armatures are in a position wherein the stabilizing tzar landing wheels (18 and 19) are swung into the proper orientation to assist in supporting the aircraft during a hard-surface landing. At full extension (not shown here) of the actuating struts (280 and 281), the armacura (6 and 7) are rotated to a position where the upper cads of the armatures and the 3 5 propeller mounts ate at a maximum distance above the wing structure ( 1 ) sad the pontoon _17_ members (22 and 23) of the compound landing gear arc in the proper orientation to assist in supporting the-aircraft during an amphibious landing. The armatures (6 and 7) are preferably shaped so that when the actuating struts (280 and 281) are fully retracted, the upper ends of the arrmantra (ti and 7) nest in recesses (not shown) in the feed wing section (1), with ono surfatx of each armature becoming flush with the aerodynamic surface of the wing and forming part of the airfoil, and the lower ends of the armatures (ti and 7) nest in recesses (not shown) of the fuselage, with dx outer surface of lower end of each artnantre becoming flush with the surface of the fuselage.
Forward landing gear are also illustrated in Figures 6 and 7 sad arc also compound, comprising a steaable forward landing wheel (21) and forward sitis (29). The forward landing gear (21, 29) arc fully rerractabie within the nose section of the fuselage, and preferably the lower surfaces of the skis (29), wbea retracted, form pact of the surface of the fuselage and thus do not create any external drag during flight. Steerable rear landing wheels (20) are also .
depiaod in Figures 6 and 7, however they arc partially hidden in this view by the forward landing w6cel (21). (See, Figures 56 and 58, item 20.) Referring to Figures 8, 9 and 10, as aircraft similar to that depicted in Figure 6 is shown, except that in these figures positioning of the compound landing gear in orientations . . . appropriate for snow landing/takeoff (Figure 8), wiser landing/ takeoff (Figure 9), and slow taxiing in water (Figure 10), respectively, are illustrated.
2 0 In Figure 8, a frontal virw is shown of the forward skis (29) and the reu skis ( 114), deployed to a position where they are acting as the primary landing gear for the aircraft. All other aspcas of Figure 8 are as illustrated in Figure 6.
In Figure 9, a frontal view is shown of the pontoon members (22, 23), rotated into proper position to act as stabilizing outriggers during a wiser landing. This positioning of the 2 5 outrigger poatoom (22, 23) is effected by full extension of the multilinic actuating struts (280, 281). Note that full extension of the multilink actuating struts (280. 281) causes the stabilizing rear landing wbeeb ( 18. 19) to be rea~acted into recesses in the lower end of the armatures (6 and '~. The primary larding geu for the aircraft in such an operation is the hull-tike fuselage.
the forwardmoat section of which is visible in this frontal elevation. The hull fuselage of the 30 embodimeaot of Figure 9 has a pronounced 'V" shape in cross-section (high deadrise aagk). In contrast to shallower bull designs, the V-shaped hull improves baadliag of the aircraft in choppy wiser and lowers the G load on the hull during water landings. All other aspaxs of Figure 9 are as illustrated in Figure 6.
Figure 10 presents the same view of the aircraft as in Figure 9, except that the auto-3 5 retracting rear stabilizing wheels ( 18. 19) have been partially lowered and the lovuer cads of thr armatures (6, 7) have been rotated slightly downward and inward by articulation of the innermost link of each of the multilink actuating struts (280. 281).
Ftotuional elements ( 18, 19.
22, 23) have thus been forcxd downward against the surface of the water, thereby leveling the aircraft and improving the taxiing performaacx of the aircraft at slow speeds on water. All other aspects of this figure are the same as in Figure 6.
Referring to Figures 11 and 12, an aircraft according to the invention and as depicted in Figures 6 and 7 is shown in frontal elevation, with the extendabk wing panels (4 and 5 in Figure 12) fully retracted in Figure 11, so that the wing tip caps (36 and 37) are mated with the feed wing tips (38 and 39) to form aerodynamic teardrop wing tips, and with the extendable wing panels fully extended in Figure 12. The main wing structure (1), the leading edge slats ( 14, 15, 16 and 17), the forward section with upper cockpit assembly (3), and the propellers (8 and 9) all are as depicted in Figures 6 and 7.
The forward skis (29) are illustrated in Figure 11 in their fully reQa~d positi~, wherein the lower surface of the skis is flush with the fuselage surface. It is an espxially preferred aspect of aircraft according to this invention that all landing gear may be fully retracted within the fuselage, out of the airstream, and that landing gear doors (and their associated mechanisms) may be eliminated. since the slti ekm~s are preferably designed to . . ~g~ ~"~, ~ ~1~. The landing gear designs disclosed herein are believed to be the first designs that combine full reu~accability of all landing gear eleaneats (wheels, skis sad pontoons) 2 0 and elimination of gear-enclosing doors from the fuselage.
Referring to Figures 13, 14 and 15, the principal aspects of the cmopound wing structure of the present invention are shown in plan. All elements depicted in Figures 13. 14 and 15 are as described in Figures 4, 1 and 3, respectively. (See, also, Figures 12. 6 and 11. ) 2 5 Ooe of the principal inventive fucurss of this inrenaon is a compatnd wing. Aircraft incorpcxating this feature have the capability of being strucaually modified, in flight, at the option of the pilot, so as to exhibit a wide range of flight c6araaeriatus m to adopt to a wide variety of flight condition. In other words. aircraft incocporadag the compound wing can be made to behave, aerodynamically, like several diffcreot types of aircraft, by the extension or 3 0 retraction of extendabk wing panels laterally from a central fixed wing sear, as discussed ~. Aircraft of impr~ed performance, versatility and safety ate the result.
The compound wing feature and possible mechanisms for its operation are illustrated in Figures 16 through 33.
Figure 16 shows the coastructton of a stuboard wing eitteasion panel (4).
Previously 3 5 discussed external features such as the teardrop wing tip cap (36), the leading edge slat ( 16) and the ailtton (12) are shown. In this figure, the outer skin (26, e.g., of flush riveud aluminum) of the panel (4) is shown cut away to reveal internal support structures, such as structural ribs (27), reinforcing stringers ~(28), a forward lift spar (30), and a rear m aft lift spar (32). All such swcaues are typically consaucted of aluminum, fastened together by rivettting. The wing extension panel (4) also features a drag spar (34) positioned between the two lift spars (30 and 32). All of the spars (30, 32, 34) extend the entire length of the extension panel and roughly ao equal length from the root .of the wing extension pail (4), A guide bar ( 116) attached to the drag spar (34) provides a racaas for guiding the extensionlrra~action movement of the extension panel (4) relative to the feed sxtion of the wing (not shown).
Figure 17 shows a more detailed view of the encircled portion XVII of Figure 16. Lift and drag spars 30, 32 and 34 are seen to have an "I'-beam shape, characterized by flange (79) and web (80) portions. At the end of the lift spars (30 and 32), beam end guide blocks (1177 are attached (e.g., riveted) into the arcs between the flanges (79) on one side of each spar (the forward side, in this figure); similarly, on the drag spar (34), a beam end guide block (118) is attached (e.g., riveted) in the area bc:wecn the flanges (79) on one side of the drag spat (34) (here, the upper side), Pairs of guide rollers (11~ are rotatably attac6a! to each of the beam end guide blocks (11?, 118). The lift spar guide rollers (11'n are positioned ao as to provide a rolls guide that will be in communication with the inside of lift spar flanges of a port wing e~etension panel. Similarly, the guide rollers (115) fated to the drag spar beam end guide block 2 0 ( 118) are positioned to accept and provide a rolling guide fa a guide bar fastened onto the drag spar of a port wing extension panel assembly (not shown), which port extension panel guide bar would correspond to the picnued starboard drag spar guide bar (116). The drag spar guide bar ( 116) is positioned to be aaxpted by a beam end guide roller system on a port wing extension assembly. This sysum of guide rollers and barn maintainer the proper interlocking alignment of 2 5 the support spars of poet and starboard wing extea~ioo assemblies.
Preferably. the drag spar guide bar (11~ sad its associated roller guides will have an interlocking tongue-std-groove shape, which will radttcs any vibration. Although the system of roller guides and bars just descn'bed is nor critical to the compound wing (i.e.. the port sad starboard wing extension panels' spars may simply be in slidable interlocking contact), the described system of guides (or 3 0 its equivalent) will ensure smooth operation of the moveable panels of the compound wing, will decrease vibration of the spars, and will minimize the possibiftty of the panels jamming is flight.
Whereas Figures 16 and 17 illustrau the relative positions of the two wing extension panels (4 and 5 in Fig. 1) of the compound wing, Figures 18 and 20 show the position of the 35 starboard wing extension panel (4) relative to the fixed wing section (l, in phantom lines), and -20~
show a preferred system of guide rollers for maintaining the position of the extension panels relative to the csmiat-fixed wing section. Referring to Figure 18, a starboard wing extension panel (4), with wing tip (36), leading edge slat ( 16), trailing edge aileron ( 12), and supporting spars (30, 32, 34), is shown in simile aspect to that of Figure 16. In phamom (dotted) lines.
approximately half of the fixed wing section (1) of the compound wing is shown, extending from fixed wing tip 38 to the centerline C (dished tine), denoting t~ central plane of the aircraft to which the wing section ( 1 ) is attached. The portion of the fixed wing section ( 1 ) shown here includes an aileron (14) and a flap (72). As shown in this illustration, the starboard wing extension panel (4) is in sliding communication with the fixed wing section (1): The extension panel (4) is picaued a full extension from tlx distal. end of the fixed wing ration (1).
and the entire assembly (e.g.. 4, 12, 16, 30, 32, 34, 36) is capable of sliding as a unit inward toward the root of the fixed wing (i.e., toward centerline C). A plurality of extension panel positioning rollers (40, 42. 44, 46, 48, 50). which are fastened to the inside of the fixed wing section (1) at the distal end, is positioned in relation to the wing extension panel (4) to snugly hold the extenaioa panel (4) while permitting (by rolling) extension and retraction of the panel (4) along the loaginrdinal axis of the wing section (1). Additional guide rollers (52 and 54) may be provided in association with some alternative mechanisms for co-acatation of the extension pane! ailerons and the fixed wing section ailerons. (See, Figure 30.) In embodime~ using cable or rod co-acatsaon mechanisms, such additional guide rollers (52 and 54) may be 2 0 eliminated. (See, Figures 33 and 32.) A further plurality of supporting spar positioning rollers (unnumbered. within encircled area 7QJ~ sxures and positions the wing extension assembly along tl>e txttterline (C), where the starboard support spars (30, 32, 34) mesh with the series of support spars (3l. 33. 35) of the port wing eximaioo assembly of the compound wing.
Referring to Figure 19, which is a more detailed view of encircled portion XIX
of Figure 18, the mahia~g juxtaposition of the port (31, 33, 35) and starboard (30, 32, 34) supporting spas of the port and starboard wing extension assemblies is illustrated. (Elemetas such as guide rollers and end guide blocks (i.e., items 115-118 in Figure 17) have bees omitted here for clarity.) Each spar is secured and guided by a pair of rollers, which are attached to the 3 0 feed wing structure (not shown):
SPAR ROLLERS
port lift spar 31 57 and 61 starboard lift spar 30 56 and 60 port drag spar 35 65 and 67 3 5 starboard drag spar 34 64 and 66 port lift spar 33 59 and 63 starboard lift spar 32 58 sad 62.
'Taken together, the series of rollers (40. 4Z, 44, 46, 48, 50, 52, 54, 56, 57, 58, 59. 60, 61, 62, 63, 64, b5, 66, 67), and additional rollers (port side) not illustrated in Figures 18 and 19, secure the moveable wing cxteasion assemblies within the fixed wing strucaire of the compound wing, ensure smooth, rolling operuion of both wing extension panels simultaneously, and maintain the proper aligaaxnt of the wing extension panels in relation to the fixed wing section. Figure 20 shows thin series of rollers in spatial relationship, with the reluive positions of the fined wing swcatre (1), starboard wing extension panel (4) and port wing extension panel (5) depicted in phantom lines (wing extension panels fully rarxtsd).
Preferably, the positioning rollers described above will be made of metal, e.g., aluminum, coated with a thin plastic or rubber skin.
A further illustration of the position and operation of the rollers is provided by Figures 21. 22, and 23. Figure 21 provides a cross-sectional view of the forward lift spar (30) and wing exte~ion panel (4) of the starboard wing extension assembly (see, Fig. 16) a~
its position relative to the fated wing strucwre (t), as maintained and secured by roller ekmeota (e.g.. 40, 44. 56, 60). Figures 22 and 23 illustrate the operuion of the compound wing, wing extension . . panel (4) is raracted as a unit toward centerline (C). The wing extension panel (4) is fully rcQacmd in Figure 23, where tlx extension panel wing cap (36) mates with the fixed wing tip (38), and the entire wing extension panel (4) is enclosed within the fixed wing structure (I).
The cooperative construction of the compound wing is further illustrated in Figures 24, and 26. which show various seaiooal views through starboard wing strucxvt es (ref. Figures 13 and 15, saxian lines A-A. &B and C-C).
Referring to Figure 24, a sectional view taken on line A-A of Figure 13 aho~ws the 2 5 structara of the s:ubosrd wing extension panel (4), as viewed along its longiwdinal axles toward the wing tip cap (3~. Several previously described fieatsurs of the starboard wing extenaian p~net (4) arc seen in cross-section: 'The leading edge slat ( 16) (fated in position by one a more strucnual rib extensions (73)). aileron (12) (pivaally aaached at one or more poi to the wing extenai~ panel (4) at str>uxural rib cxtemions (74) through beuinga (75), 3 0 forward lift spar (30), drag spar (34), and aft lift spar (32). Guide bus (11~ art visible in this figure ~t ody oo the drag spar (34) but also on the web of the two lift span (30 and 32).
Figure 24 further shows reinforcing stringers (28), which run subata~ially the entire length of the wing extension panel (4) and arc riveted to the underside of the clue skin (26) of the panel.
Figure 24 additionally sho~wa clearance holes 76, 78, and 77, which are provided to 3 5 accommodate the corresponding forward lift spar, drag spar, and aft lift spa, respectively, of a port wing extension panel as the two extension panels slide together within the fixed wing structure of the cea~ound wing. (See. Figure 26.) Referring to Figure 25, a sectional view taken on line H-B of Figure 13 shown the srrucaues of the starboud wing extension panel (4), as viewed in a fully extended position, looking spanwise, toward the wing tip, from a point just inboard of the faced wing tip (38).
Several previously described features of the cotnpound wing are seen in cross-section; The leading edge slats (14, 16), strucairal rib extension (73), positioning rollers (40, 42, 44, 46, 48.
50), guide bars (11~, panel skin (26), stiffening or struc:aual rib (27), ailerons (10 and 12), swcairal rib extension (74), bearing fastener (75), guide rollers (52 and 54), forwud lift spa (30), aft lift spa (32), drag spa (34), and cleuatxe holes (76, 77 and 78).
Additional strucaires of the fixed wing section are also visible in Figure 25, i.e., fore and aft supporting spas (68 and 69, respxdvely).
Referring to Figure 26, a sectional view taken on line C-C of Figure 15 shows tlx structures of the starboud wing extension panel (4), as viewed is a fully retracxed position, looking spanwise toward the wing tip, from a poittt just inboard of the fixed wing tip (38).
Referring motneatuily to Figures 13 and 15, it will be apprxiated that in contrast to the view in Figure 25, the view of Figure 25 -is taken when the wing extension panels (4 and 5 in Fig.
13) are fully reaactod. and thus many of the associated iataaal support structures are imermes6ed. Previously described features of the compound wing aeon in Figure 25 are also 2 0 seen here in noes-section: The leading edge slats ( 14, 16), structural rib extension (73), positioning rollers (40. 42. 44. 46, 48. 50), guide bars ( 11~. Panel skin (26), stiffening or swcxural rib (27), ailerons ( 10 and 12), structural rib extension (74), beating fastener (75), guide rollers (52 and 54), forward lift spar (30), drag spat (34), art lift spa (32), main wing supporting spars (68 and 69), and cleuance holes (76. 77. 78). Additional structures, i.e., from 2 5 a port wing extension assembly that have retracted into this sectional view of the stuboud wing, are now seen: The foewud lift spar (31), with associated end block (11'n and guide rolkra (11~, which ate in rolling communication with the guide bar (116) fastened to the web of the focvvud lift apu (30) of the starboard wing extemion assembly: the port drag spa (35).
with associated end block ( 118) and guide rollers ( 113), which ate in rolling communication 3 0 with the guide bar ( 116) fastened to the web of the stuboard drag spa (34); sad the aft lift spar (33), with assaiated end block ( 11?) and guide rollers ( 115), which are in rolling communication with the guide bar ( 1 l6) fastened to the web of the aft IiR
spar (32) of the starboard wing extension asstmbly.
From Figures 25 and 26 it will be appreciated thu cleu>Inae boles (76, 77, and 78) are 3 5 cut in each of the structural ribs (27), which ue spaced approximately 1-1 ~h fen apart for the length of each of the wing sections, in accordance with conventional wing comroruction. These passages (7G, 77, ~8) are sized and positioned to permit the wing extension spars (31, 33, sad 35) of the port wing to pass through substantially the entire length of the starboard wing extension panel (4). Similar clearance holes will exist in each of the saucdual ribs of the port wing cxuosion asxmbly. Further detail of the relative positions of the overlapping spars is shown in Figure 36.
Exteasioa and retraction of the wing extension pane4s may be eff~d by any means that reliably moves both panels simultaneously. Differenaal extension or retratxion of the panels which results in bilaterally asymmetrical wing span will increase yaw and result in loss of directional control. Several suitable methods for actuating the components of the compound wing described herein will be apparent to those skilled in the art, however by way of illustration Figures 27. 28, and 29 depict two suitable mxhanisms.
Figure 27 depicts a cable system for retracting and extending the wing extension panels.
In phamom lines, the starboard side of the fixed wing structure (1) is shown enclosing the lift and drag spars (30, 32, 34) of the starboard wing extension panel (4), and the extension panel (4) is fully extended. Also shown in phantom lines are the opposing lift and drag spars (31, 33.
35) of the port wing extension panel: In the system illustrated bent, extension sad retraction of the wing extension panels is controlled by two control cables (158 and 159).
Optional coordinating cables (301 sad 302) may also be provided as a safety measure, to ensure that the 2 0 port sad starboud wing extension panels will always be extended ~
retracted to substantially the same degree.
One end of cottaol cable 158 is attxhed to the starboard forward lift spar (30) neat the base of the wing esteasion panel (4). The cable (158) is threaded through a pulley (161) rotatably fixed to the fixed wing structure (1), through an anchor block (304). through another Z5 pulley (161) atmched to the fuel wing saxion (1), and the orbs end of the cable (158) is attached to the opposing port forward lift spar (31) near the base of the port wing extension panel (not shown). The anchor block (304) is auac6ed to a specific poi of tha cable (i.e., the midpoint). and the c~croi cable ( 138) caaaoc slide through the aachoc block (304).
Alternatively, of courx, two cables could be employed wherein one end of each cable is 3 0 aaached to the anchor bloct (304) sad the other erd of each cable is attached to the port or the starboard lift spar near the bax of the rapoaive wing eaneruion panels.
T~ set:ood control cable ( 159) is attached at one end of the starboard lift spar (30).
threaded through a pulley (161) rotuably attached to the feed wing struawre (1). through an anchor block (303), through another pulley (161) rotanbly aaached to the fined wing structure 35 (1), then attached to the end of the opposing port lift spar (31). Again, the single control cab~c (159) may alternatively be substituted with two cables. both attached to the atx6or block (303) at o~ end and t>ten attached respectively to either the port or starboard lift spars.
A belt or chain ( 160) is attached to anchor block 303 at one end, threaded around a drive pulley ( 162), anti attached at the other end to anchor block 304. The belt ( 160) is driven by the drive pulley ( 162), which, in tuna, is controlled by a motor or mechanism (n~ shown) aaached w the main wing savcaire ( 1 ). In operation, when the drive pulley ( 162) is rotated counterclockwise, control cable 158 is pulled, and control cable 159 is relaxed, t~reby drawing the wing extension assemblies together (retracting the wing extension panels).
When the drive pulley (162) is rotated clockwise. control cable 159 is pulled and control cable 158 is relaxed.
thereby extending the wings. The arrows in Figure 27 show the direction of movement of the cables ( 158, 301, and 302) when the drive pulley ( 162) is turned counterclockwise and the extension panels are retracxed.
Because asymnxaic extension or retraction of the wing extension panels, e.g., due to a comrol cable failure, would cause a lass of control characteristics, an optional fail-safe mechanism for keeping the movement of the wing extension panels coordinated may be employed and is illustrated in Figure 27. Two coordinating cables (301 and 302) are utilized:
Cable 302 is attached at one end to the tniddk of the starboud aft lift spar (32) near the base of . . ~ swing extension panel (4), thraded around a pulley ( 164) which is aaac6ed to the fixed wing section (1). then attached at its other end to the end of the port aft lift spar (33): and 2 0 similarly, cable 301 is attached at one end to the middle of the port aft lift spar (33) near the base of the port wing extension panel (not shown), threaded around a pulley (164) which is attached to the fixed wing section ( 1 ), then attached a its other end to the end of starboud aft lift spar (32). In the event thu any of the coaQOl cabka (158. 159) fails, the coordinating cables (301. 302) would eaittre that the degree of exteanion or retrxtioa of the port and scarbomd wing extension assemblies would be subataatially the same.
Figure 28 is a detailed view of encircled portion XXVIII of Figure 27. All of the feaatra (drive pulley (162), anchor blocks (303, 304), control cables (158, 139), drive beh ( 160), pulleys ( 161. 164). starboard and port lift spars (30. 31. 32. 33).
starbos~rd a~ port drag spars (34. 3~, and coordinating cables (301. 302)) are as described abm~e.
Arrows in this 3 0 figure show the diration of movement of the adjacent structure (pulley, spar, or gable) as the wing extension panels are reeacted by counterclockwise drive of the drive pulley (162).
Alternative mahods for actuating a cable cocttrol system such as thu of Figures 27 and 28 will be appartoc to those skilled in this art. For example. the anchor blocks (303 and 304) could be attx6ed to threaded nuts at either end of a leadscrew, instead of being attaclud by a 3 5 drive belt ( 160) as illustrated Referring to Figure 29, as aluraace method of extending and rtt~cang the wing extension panels is shown. Most of the strucwral items of this figure have been described previously and are'the same as illustrated in Figure 27. Instead of the cable control system of Figure 27, however, there is a leadscrew (217) that extends from tip to tip of the fixed wing section ( 1 ). One end is threaded with a right hand thread and the other end has a left head chrad. An appropriately threaded leadscrew nut (218) is attaci>ed to the wing extension panel (4), and a leadscrew drive motor (219) is provided that is capable of rotuing the leadscrew in both clockwise and counterclockwise direcrions. Opcratiou of the drive motor (219) cause the leadscrew nut (218) to be pushed outward or pulled inward, depending on the rotation of the leadscrew, with a consequent extension or raracdon of the wing extension panel (4).
The final aspax of the innovative compound wing of the present invention that must be addressed is the co-actuation of the ailerons of the fixed wing and of the wing extension panels.
If the extension panel ailerons do not operate in concert with the fixed wing ailerons, the .
airplane becomes much more difficult to control. Accordingly, the full advantages of the compound wing ascribed herein will not be realized without adopting some mahanism for co-actuation of the ailerons. Several mahaaisms will suggest themselves to those skilled in the art, and three such mechanisms arc illustrated in Figures 30, 31, 32, and 33.
Referring to Figure 30, which is a cross-sx~tional view taken s~long line J-1 of Figure 15, a partial view is shown of a starboard wing extension panel (4) retracted within the fixed 2 0 wing structure ( 1 ). Several of the structural eleme~ such as support spars. clearance holes, and guide bars and rollers have been described previously and are the same as depicted in previous figures (see, e.g., Figure 26). An additional feature Shawn in this figure is an aileron actuuor plate (85) fastened to the fixed wing structure (1) by actuator plate guides (87), which permit sliding reorieamtion or pivoting of the accuuor plate (85) along guide slots (86) cut in 2 5 the plan. in response to conventional actuation of the fixed wing aileron ( 10), through conneaing arms (88 and 89). The aileron actuator plate (85) also acts as a housing for two guide roUat (52 and 54), which are in rolling communication with the extet~tion panel aileron (12). It is readily seen that movement of the fixed wing aileron (10) is automatically trattalated via the aihxon atxvator plate (85) and the guide rollers (52 and 54) to the extension panel 3 0 aileron ( 12); and because the aileron actuator plate (85) is in contacx with the extension panel ailer~ (12) through mllaa (52 and 54), the acxion of the fixed wing aileron (!0) is translated to the extension panel aileron ( 12) during extension or retraction and regardless of the degree of extension or reaaaioa.
Figures 30 and 31 show two views of the same wing structures. In Figure 30, the 3 S ailerons ( 10 and 12) are raised; and in Figure 31, ailerons ( 10 and 12) arc lowered.

Comparison of these two figures illustrates the pivoting reorientation of the aileron actuator plate (85) and associated linkages (88 and 89).
Referring to Figure 32, a preferred mei6od of actuating the wing extension aileron in concert with the fixed wing aileron is shown. The fixed wing ailerons (10) are controlled by moves of a sliding actuator bar (103), which movement is translated to the fixed wing aileron ( 10) through a conventional arrangement of bellcranks and rods. The actuator bar ( 103 ) runs through bar guides (122), which are fixod to the fixed wing section (1) along the centerline of the fuselage. The flaps are controlled by means of a control rod (30~, the movement of which is translated to the flap (72) through conventional lintcagea.
It is often advantageous to co-aca~ate flaps and ailerons to increase lift (drooped ailerons) or increase roll control (flaperons). Figure 32 illustrates a system wherein, if control rods 306 and 307 are co-actuated (i.e.. under cotmol of the flap lever), then aileron (10) will assist ttu: action of the flap (72).
For co-acwuion of the extension panel aileron (12) in concert with the fixed wing aileron ( 10), Figure 32 illustrates a cable system controlled by the same sliding comrol bar (103) that actuates the linkages to the fixed wing aileron (10). In this embodiment, an aileron actuator cable (105) is attached at one end near t~ end of the forward lift spar (30), threaded through an actuuor guide pulley (101) rotacably attxlxd to the fixed wing sn~ux~ue (1), through an aileron control pulley ( 157) rotacably attached to the control bar ( 103), through another 2 0 actuator guide pulley ( 101 ) rotatably attached to the fated wing strucaue ( 1 ), through another guide pulley (i04) rotatably attached to the lift spar (30) near the base of the wing exunsion panel (4), then attached at its other end tv a sectioned pulley ( 100) fixedly attxhed to the extension panel aileron (12). A second aileron acaiator cable (106) is attached at one end of the sectioned pulley (100), threaded through a guide pulley (104) rotatably attached to the aft lift 2 5 spar (32), through an acdator guide pulley ( 101 ) rotatably attached to the fated wing section ( 1 ), through an aileron conarol pulley ( 157) rotatably aaached to the aileron control bar ( 103).
through another acxttuor gui~ pulley (101) rotatably attached to the feed wing structure (1), then attached at its other end near the end of the aft liR spar (32).
It will be apprxiated from Figure 32 thu when the sliding ca~trol bar (103) is moved.
3 0 this arrangement of cables ( 105. 106) and pulleys ( 101. 104. 15~ causes one cable (i.e.. 105 or i06) to slacken while the other cable tightens with respax to the sectioned pulley (100), which causes that pulley to rotate and thus raise or lower the extension panel aileron (12) accordingly.
It wilt also be appreciated that as the wing extension panel (4) is retracted, the entire wing extension assembly, including the starboard lift spars (30 and 32) will roll imvud, across the 3 5 longitudinal axis of the cottorol bar ( 103), but the relationship of the cables ( 105, 106), control bar (103), sectioned pulley (100) and aileron (12) is preserved: As the liR
spars (30 and 32) roll across the-longitudinal axis of the control bar (103), the actuating cable (105 and 106), which are attached to the ends of the liR spars (30 and 32) will move as a unit with~the 1iR spars (30 and 32), sliding through the arrangement of pulleys (101, 157) but not alttring the ability of control bar movemems to be directly translated to the panel aileron ( 12).
A corresponding actuating system for the port side extension panel aileron is indicated in Figure 32 by the corresponding cables (120 and 121) attached to the port fore and aR liR
spars (31 and 33), the ends of which are indicated by phantom lines. The arrows in Figure 32 show the direction of movement of the components of the system when the control bar ( 103) is moved forward.
The bellcranks, rods, pulleys and cables depicted in Figure 32 are all of standard construction and are typically fabricated of stainless steel. The size (diataeter) of the pulleys (100, 101, 104, 157) and positioning of tht aileron coturol pulleys (157) with respax to the actuator guide pulleys ( 101 ) fixed to tlx wing section ( 1 ) will be calculated so that the amount of cable slack paid out or taken up by movement of the control bar (103) does not exceed the amount of cable required for the entire range of movement of the aileron (12).
Viewed another way, it will be rcpt in mind that in the arrangement of cables and pulleys illustrated bore. if the . . aileron control pulleys ( 157), moving with the comrol bar ( 103), are taken up to or beyond the point of alignnxnt with the spar guide pulleys (101) through which the associated cable (e.g., 2 0 105, 106) is threaded, the aileron control pulley ( 157) would no longer be in effective contact with its associated cable, and movement of the control bar ( 103) world no longer affect the .
tension of the actuation cables ( 105, 106). Pulleys accordingly will be sized and positioned in relation to each other so as to maintain control of tde aikrona.
Relating to Figure 33, an alternative system for co-acatarioa of the fixed wing aileron (10) and the extension panel aileron (12) is shown. In this system. cable linkages are resp~sibk for atxusdon of all ailerons ( 10. 12) and flaps (72), rather than a combination of cable linkages and conorol rods. bars and bellerank-type joints. (Cf. Fg.
.32.) The acatation system for the extension panel aileron is essentially as depicted in Figure 32. For actuation of the starboard fixed wing aileron ( 10) and starboard flap (72), the control bar ( 103) is coat>eaed 3 0 to the fixed wing aileron ( 10) via two cable ( 124 and 125). Cable 124 is fastened at one end to the control bar (103). threaded through an inner aileron acatator pulley (123) rotatably fastened to a pivoting master flap actuator plate ( 156) (controllable by the pilot by a mechanism not shown here), through an aileron guide pulley ( 108), then fastened at the other end to a sectioned pulley ( 107) fixedly attached to the aileron ( 10). Cable 125 is similarly attached, in opposing 3 5 fashion with respect to cable 124, as shown in Figure 33. A sectioned pulley actuating plate (155) fixtd to the main wing flap (72) is similarly attached, via two cables (308 and 309), through guide_pullexs (154) to the pivoting master flap acwacor plate (156), as shown.
Ia operation, pivoting of the master flap actuator plea (156) by the pica cauaa the flap (72) and the main wing aileron ( 10) to move together. Fore-aft moveo~t of the aczwtor control ion wing aileron (12) co move in concert.
A corresponding actuating sysum for the port side extension panel and fixed wing section ailerons is indicated in Figure 33 by the correspoadiag cables (120 sad 121 for the wing eauasion panel aileron; 126 and 127 for the fixed wing section aileron) attached to the port fore and aft lift spars (31 and 33) and the maser flap actuator plea (156), respectively. Aa in Figure 32, the inboard end of a port wing exunsion panel assembly is depicted in phantom lines. The arrows in Figure 33 show the dirxtion of movement of the components of the sysum when the control bar ( 103) is moved forward.
The Engi and It-Driven Propellers Preferred aircraft according to the present invention will employ as innovative power train and means of propulsion incorporuiag two engines, mounted inboard (i.e., within the fuselage on the centerline of the aircraft), which drive (via a system of drive belt;) two puaher-type Propellers mounted on the wing ~or, moat preferably, on mounting armatures such as . . described previously that permit the position of the propellers to be changed at the option of the pilot. This propulsion system not only harmonizes with other aeronautical discoveries described 2 0 herein. such as the bilaterally exundabk compound wing. the pivoting mounting armatures and the multi-purpose compound landing gear, but also eliminates many safety hazards unavoidable is conventional multi~engine aircraft, improves the efficiency of the airfoil, eliminates gravity loads that conventionally must be borne by the wings, offers greater protxtion to the engines sad lowers the aircraft's unur of gravity while utilizing space normally wasted is conventional aircraft, sad virtually eliminates the dangers ordinarily associated with unexpxted failure of one engine.
According to the present invention, two engines are mounted in the fuselage of the aircraft, in tandem and in oppaaed relation. ~iately aft of the cabin secxion, undo the wings. Referring momentarily to Figure 51, which is a cross-satiooal view of the midsection 3 0 of as aircraft according to the invention, two aircraft engines (24 sad 25) are seen in silhouette.
Air~sooled aircraft engines, such as the sixtylit~er, horizontally opposed Lycoming 10-540.
are suitable, however water-cooled automobile engines, such as a GMC 454-cubic inch V-8 engine, would also be suitable.
The engines are preferably mounted, using conventional rubber engine mounts, to a 3 5 steel frame, which frame is bolted to the fuselage. This permits easy removal of the engines for servicing or replacement. Moreover, if changes occur in the specifications for the engines (or changes occur in regulations governing the power rcquiremeots), the engines can be switched without the necessity of designing new external engine mounts, fairings or nacelles, and without refiguring the physics of the airfoil. Thus, even where the aircraft is in mass production, a complete alteration of the power plant can be implemented without interruption of the production line or retooling of production mxhinery.
Mounting two engines in opposed relationship permits the propellers to be driven in opposite dirations (counter-rotating propellers), without requiring one engine to be a custom-made counter-rotating engine. There are several disadvantages to multi-engine aircraft with propellers thu turn in the same direction. Such aircraft have a tendency to yaw in one direction (left or right) for several reasons rooted in the same-direction motion of the. propellers:
Reaction of the aircraft to the torque required to turn the propeller, asymmetric thrust due to unequal angles of aaack of the upward-turning and dowmvard-turning blades, the effax of the twisted air flow behind the propeller, and gyroscopic turning moments. All of these forces tend co compromise tlx controllability of the aircraft, and the negative traits can be amplified where there is a differential power output to the propellers.
in an aircraft according to the invention, two identical engines can be used to drive two oppositely rotating propellers, and the disadvantageous rextion to torque, asymmeaic thrust and gyroscopic turning momem resulting from one rotating propellor are all cancelled by the 2 0 opposite forces of a counter-rotating propeller. The turbulence behind the propellers is also balanced, and the aircraft rotational inertia is minimized by plxing the items of greatest mass (the engines) near the center of gravity. in addition, since the engine mass is near the center of the fuselage rather than on the wings. the of gravity is lower, which is especially beneficial to amphibious aircraft for taxiing and performing other optruioas on the water.
2 5 In conventionally designed multi-engine propellor aircraft, the engines are housed in nxelks on the wings. Although the nxelles are. shaped to be as aerodynamically harmless as possibk, these is no escape from the fax the area of the wing surfxe taken up by the nacelles and aft of t~ nacelles provides no lift. and the nacelles themselves creue drag. These disadvantages are eliminated by plxing the engines inboard and modifying the wing surface 3 0 only to the extent necessary to xcommodate the propeller mounts. The efficiency of the airfcaa~e is thus improved. ' Conventionally mounted propellerlengina on a multi-engine aircraft must be located far enough from the longitudinal centerline of the aircraft for the propellers to clear the sides of the fuxlage. This distance off the centerline makes conventional multi-engine aircraft difficult to 3 5 control in the event of an engine failure, which requires immediate correction of the asymmetric thrust provided by the live engines) and sudden drag of the dead propeller/engine if uncontrollable~spia.er unintentional "wing-over" are to be avoided. These hazards are eliminated in aircraft according to the present invention, because by employing a system of overrunning clutches and a simple gearbox (see Fig. 37, discussed j>~, the failure of one inboard engine will not lead to the failure of either propeller. Rather, the power from the engine that remains in service is transferred instantly to both propellers, requiring the pilot to adjust only to the power reduttion and not requiring compensation for a sudden imbalance of thrust and responsiveness of the control surfaces.
Referring to Figure 34, the midsection of the aircraft pictured in Figure 15 is shown in cross-section (view I-I). The relative position of the eagine (24 and 25) to the fixed wing structure (1) and the fuselage (300) is seen.
Figure 34 also shows, within the fined wing structure ( 1), the intermeshed support structures of fully retracted starboard and port wing extension panels, including the forward lift spars (30, 31) and guide rollers (56, 57, 60, 6l), starboard and port drag spars (34, 35) and guide rollers (64, 65, 66, 67), and starboard and port aft lift spars (32,' 33) and guide rollers (58, 59, 62, 63). Support structure of the main fixed wing section (1) are also shown, including a forward main wing spar (68) and a rear main wing spar (69).
The two engines (24 and 25) drive overrunning clutches (109) which allow torque (power) to be transmitted in one direction only (in this case clockwix). In the opposite direction the clutche (109) turn freely. The rear engi~ (24) and its overrunning clutch (109) drive a shaft (172) on which a belt pulley (96) (or, alternatively, a chain sprocka) is attached.
The belt pulley (96) drive a cog belt (99) (or chain), which cog belt (99), in turn, goes on to drive mechanisms in the port wing not seen in this figure. In addition to driving the port belt pulley (96), the rear engine shift (172) also drives a gear (184 in Fig. 37.
discussed ~ inside 2 5 a gearbox ( 110).
In like fashion, the forward engitx (25) and its overrunning clutch (109) drive a forward engine shaft (173), on which are attached a gear (187 in Fig. 37, discussed ~
in the gearbox ( 110) and a starboard belt pulley (95) (or, alternatively a chain sprocket).
This beh pulley (95) drives a cog belt (99) (or chain), which runs to the starboard side of tlx wing as shown is 3 0 Figure 34, and drives a pivot transfer pulley (94). The pivot transfer pulley is attached to a pivot transfer drive shaft (291 ) rocatably mounted in bearings ~(82) attached to a forward upper armature spar (70) and a rear upper armature spar (71 ). There is a co-axial armature pivot shaft (91) running through the length of the pivot transfer drive shaft (291) and extending fore and ati to armature pivot bearings (97), which are attached to the rear main wing spar (69) at the 3 5 forward end and a rear auxiliary wing spar (98) at the aft end. The pivot transfer drive shaft (291) is therefore itself a tubular bearing, freely rotatabk about a co-axial armature pivot shaft (91 ).
Referring momentarily to Figure 1, it will be recalled that the propellers (8 and 9) are preferably mounted on pivotally mounted armature (b and 7) that may be raised and lowered to change the position of the propellers relative to the wing (1). The cog belts (99 in Figure 34) driven by ctu; inboard engines (24 and 25 in Figure 34) extend, in this embodiment, to the pivot points of the armatures where the engines' power is transferred to propellor drive belts extending into the upper ends of the armatures (6 and 7) to drive the propellers (8 and 9). Of course, in embodiments thu do not incorporate the armature sttucaues disclosed herein, the cog belts (99) may extend directly to pulleys aaached to propeller shafts mounted in the wings.
As shown in Figure 34, the starboard cog belt (99) drives a aaasfa pulley (94) feed to pivot aansfer drive shaft (29t), which extet~.s from a forward upper armawre spar (70) to a rear upper armature spar (71). Also attached to the pivot transfer drive shaft (291) is a pivot aansfer drive pulley (93). The spinning of the pivot transfer drive shaft (91) and pivot traaifer drive pulley (93) drive a propeller drive belt (84) (or, alternuively, a chain), which extends to a starboard propeller drive pulley and shaft (not shown). Alternatively, a single rrnatabk pivot shaft may be utilized in place of the co-axial shafts 91 and 291, but this is less preferred, since . _ then a constantly rotating pivot shaft would be a the of all the mourning armaatre pivot points. Another alternative would be to have a single stationary pivot shaft and to have both the 2 0 cog bclt (99) and the propellor drive belt (84) cooaaxed to a single freely spinning pulley mounted on the pivot shaft (repluing the trarufer pulley (94) and the pivot transfer drive pulley (93)), or connected to separate pulleys which arc fastened togaha.
In the arrangetnern of drive belts shown in Figure 34, small idler pulleys (90) adjust and maintain a desired torsion in the belts (84 and 99). Staodtird, comaxrcislly obtainable toothed 2 5 belts (timing belts) constructed, e.g., of steel reinforced rubber. may be used throughout this system. In the moat prt:fared embodiments, the compo~orts of the power train will be positioned so that all four drive belts (2 x 84 and 2 x 99) are the same length. Likewise, standard toothed pulleys, shafts and bearings used in modern aircraft construcxion are suitable.
Propcr selection of the diameters of pulkya~ 83, 93, 94, 95, and 96 provide an overall 3 0 speed reduction ratio that allows the engines (24 and 25) to run a a relatively feat speed (4400 rpm, for example), for optimuat power production, while the propellers may turn at a relatively low speed, i.e., without approaching their maximum design speed (2700 rpm, for example).
This propeller speed reduaioa eliminates the need for a costly spend reduction gearbox uscd on some existing aircraft engines.

Incidentally, the positioning of the engines, cog belts and propellers a described above places these majoraeurces of the aircraft's aoix behind the cabin uea. This will result in an aircraft that is comparatively quiet from inside the cabin, even though the engines are inboard.
Figure 35 is a cross-xctional front elevation of the aircraft illustrating the relative positions of several components already discussed. The position in the fuxlage (300) of the rear engine (24) is shown in solid lines; the position of the forward engine (25) is seen in dotted lines. This figure shows how the starboard and port cog belts (99) extend into the mounting armatures (6 and 7) to actuatt the pivot transfer drive shags (291), at the pivot points of the mounting armatures (6 and 7).
Rotation of the pivot transfer drive shafts (291 ) causes propeller drive belts (84) to turn the starboard and port propeller drive pulleys (83), which arc attached to the starboard and port propeller drive shafts (81), to which the starboard propeller (8) and port propeller (9) are attached. Through these belt and pulley linkages, the power of the engines (24 and 25) mated inside the fuselage (300) is transferred to the propellers (8 sad 9) mounta3 on the armaturas (6 and 7) (or, alternatively, mounted in the wings). The positions of idler pulleys (90) is also shown in this figure.
Figure 36 provides a plan view of the midsection of ao aircraft incorporating the compound wing, mounting armatarres sad internal engine mounting features of the prat invenaoa. Nearly all of the strucaires pictured is Figure 36 have been described previously and have the same item numbers as in previous figurGS (sae, e.g., Figures 1, 13, 16. 26, 34 sad 35).
The engines are represemed in this figure only by the shafts 172 and 173 (see, Figure 34).
Additional preferred auxiliary spars for the wing (98) and for the mourning armature (119) are shown here and were not inchtded is previous figures.
The interlocf~ing relationship of the support structures of the extendable wing panels (4 and 5) is clearly s6owo in Figure 36. With the extension panels (4 and ~ in partial extension.
as shwva, the starboard and poet focwud lift spars (30 and 31), the starboard sad port drag spars (34 sad 35), sad the starboard and port reu lift spars (32 and 33) are saes to overlap within the enclosing structure of the fixed wing section (1). From this figure it is seen that whoa the wing exteruion panels (4 and 5) are fully reQacted within the fixed wing structure ( I ).
each of the wing exteasioo asxmblies extends across nearly the entire (fixed) wing span, i.e..
from wing tip to wing tip.
Figure 36 also shows the plan of the drive belts (84 sad 99) that cansfer the power provided by the engines (represented here by shafts 173 and 172) to the propellers (8 sad 9).
Assuming clockwise rotation of the opposed engine shafts ( 172 sad 173), the arrows in Figure 3 5 36 show the direction of the belts (84 sad 99), which produces inwardly counter-rotating propellers. Inward counter-rotation of the propellers is preferred. As an added safeguard, the single drive belts X84. a~ 99) shown in Figure 36 and other drawings (e.g.. 99 in Figs. 37, 38.
41) may be replaced with two, or more preferably three (or more) parallel drive belts, arranged side-by-side and separated by sheet metal dividers. 'The plural drive belts would provide continued power aaasfer to the propeller in the event of the failure of one belt. The dividers would prevent a failed belt from interfering with an operating beh.
Referring to Figure 37, a diagram of the simple gearbox (110 in Figure 34) is shown.
T6e gearbox permits power from one engine (24 or 25) to be automatically transmitud to both propellers, in the event of the other engine failing or being shut down.
Diaeagagiag the gears, by means of a gearing control um (111), makes the rotation of the propellers completely independent.
T'he gearbox (110) pretierably houses five gears (184. 185, 186, 187 and 315).
Gear 184 is driven by the rear engine (24); gear 187 is driven by the forward engine (25). T1x two gears 185 and 186 are idler gears, and gear 315 is an idler gear thu can be moved along its shaft (see double-headed arrow) by means of the gearing comrol um (111) while in motion.
T'he moveable idler gear (315) can be positioned so that it is disengaged from idler gear 185 (pictured), or it can be poaitiooed so as to mesh via dogfaa sprockets (unnumbered) with gear . . 185. The. idler gears 185 and 315 in Figure 37 may alternatively be replacxd by a single moveable idler gear that can be mound to engage both gears 184 and 186.
2 0 In the fully eagagod position. the gears ( 184, 185. 186, 187 and 315) in the gearbox ( 110) cause the pulieya, belts, and propellers in this design to operate as o~ system (i.e., both propellers run at the same speed). With the gearbox disengaged, the front engine (25) and the port propeller (9 in Figure 36) and associatred pulleys and heirs run as a separate system from ttk rear engine (24) and the starboard propeller (8 in Figure 36) and associated pulleys and belts. In the disengaged eoofiguruioa the aircraft operates much like a comeationa! cwin-engine aircraft, at last in terms of the independence of the two propulsion systems. A grew safety advantage is realized when tl~ gars are engaged: The two propeller drive systems are conned by mans of the garbox to each other, so that if power from one engine should be compromised the other engine would automatically provide power to both propellors evenly 3 0 without requiring the pilot to take corrective action. Thus, with the gars engagtd, a single engine shutdown does not lead, as in conventional multi-engine aircraft, to the aircraft being suddenly asymmetrically powered, and consequently the aircraft atxordittg to the im~ention acquire the performance advantages of multi-engine aircraft while achieving the operating simplicity of singktngine aircraft, and they realize the best of the ssfay charaaaristics inherent 3 5 in each type of aircraft.

7?316-13D

The capability of unifying the power trains of all propellers through a simple gearbox as just described-v~'till~ive several carry-through advantages in subservient systems t6u may also be unified correspondingly. For example, in conventional enginelpropeller systems, a separate propeller governor geared to the engine provides a means of adjusting the pitch of the propeller blades to maintain a speed set by the pilot. In accordance with this invention, both propellers may be driven at the same speed through a common gearbox, thus individual propeller governors to set the speeds of the propellers is not necessary. Instead, ~atu such as as automatic hydraulic selector valve may be provided so that engaging the gears, e.g., via gearing codarol arm 111 (Figure 3'n, will automatically select o~ propeller governor to conaol ail the props, leaving the remaining propeller governors) as safety backups.
A particularly innovative feature of preferred aircraft according to this invention is the incorporation of pivotal mounting armatures, already discussed with refrcence, e.g., to Figures 1, 4, 6, 7, 34, 36 (and many of the other drawings). Further appreciation of composition and function of the pivotal mounting armatures will be gained by reference to Figures 38, 39, 41, and 42, which show starboard and port mounting armatures isolated from the body of the aircraft but in proper spatial relationship to each other. as if they were installed on an aircraft in aaordaoce with the teachings herein.
Referring to Figure 38, opposingly positioned starboard (6) and pmt (7) mounting 2 0 armaaires are shown in perspective, in thr oriemation they would have ia.
e.g.. an aircraft as pictured in Figure 5 (landing gear retracted, propeller centers level with the wings). Flotadonal pontoon landing gear (22 and 23) are incorporated in or mounted at one end of each mounting armature (6. ~). and a starboard caster-type stabilizing wheel ( 18) is shown retracted into a rece.~aa in the starboard pontoon (22) (the like port caster-type stabilizing wheel is not visible 2 5 in this view). The piva points of each armature are indicated at P im Figure 38, and it is through the piva poims that the mourning armatures (6 and 7) are pivotally fixed to the main wing sttvcaue (1 in Figure 36) by a pivot shaft (91 in Figure 36). The Propellers (8 atd 9, indicated by cinvlar arcs in Figure 38) are mounted at the opposite end of either armtawre (6. 7) from the landing gear. in nacelles (314) formed in the surface of the armatures. The beh-and-3 0 pulley drive system for the propellers. discussed previously with refetrncx to Figures 34. 35 and 36, is recalled in this figure by the partial cog belt (99) and the pivot transfer drive shaft (291 ). The propeller drive belt (84 in Figure 36), and the propeller drive pulley and shaft are uxlosed within the mounting armature and thus are mot visible in this drawing.
The pivotal mounting armatura of the present imverttion provide a means of 35 coordinating the placement of the propellers and the exposure of different types of IandinR gear.

It will be appreciated by reference to drawings such as Figure 38 that the campourtd ia~ing gear mounted at t~_lower ends of the armatures are rcpt at substantially the same distance from the propellers mmtnted on the upper ends of the armatures. But while the separation of landing gear and propellers remains constant, their orientation with respetx to the rest of the aircxaft (and the ground) may be changed, baaux of the pivotal attachment of the armatures to the fixed wing swcture ( I in. Figure 1 ) of the aircraft.
Referring to Figure 39, the armatures (6 and 7) may be considered as having an upper end (or propeller cad) and a lower end (or landing gear end) with respect to the pivot points (P).
For example, the upper end of armature 7 in Figure 39 is indicated by the screwed line U-U, and the lower end of the armature 7 is indicated by the screwed line L-L.
While not wishing to be limited to one particular shape or any particular set of cenerete dimensions. the preferred mounting armatures depicted in the drawings may be broadly described as incorporating four segments, at differing angles to one another, indicated as W, X, Y, and Z in Figure 39. A
dashed line represents a centerline through all four xgments of mounting armuure 7, It will be appreciated chat segments W and Y are substantially perpendicular to exh other. since. in the orientation illustrated hers, xgment W is coextensive with the wing sttucarre and Segmem Y is coextensive with the fuselage. The relative angle of xgment X, which connects segments W
and Y, may vary widely according to design choitxs but ideally is sufficient to accommodate the angle of a single drive belt (e.g., 99 in Figure 35) extending from the inboard engine shaft (172 2 0 or 173 in Figure 34) to the transfer pulleys on the pivot shafts (e.g., 291 is Figure 35). The angle of xgment Z, which extends inboard from segmem Y, also tray vary widely in accordance with design choice but ideally is sufficient to conform the angle of tlu segment Z to the angle of ttu keel of the hull-type fuxlage (300 in Figure 35). The barrier dimensions of the armaatres will geoaally follow the centerline but may taper and curve in order to provide 2 5 fairing, to improve the fit of the armature into recesses, or to mare the outer surfaces of the armantrea aerodynamically smooch or capable of merging with an xrodyttamic surface (i.e..
wing or ft~elag~e).
Referring again to Figure 39, the praise dimeaiioos of the xgmeots W, X. Y and Z
may vary, so long as at least one object of the invention is accomplished.
Segment W must be 3 0 long enough to prevent the propeller blades (8 and 9) from striking the fuselage a all points of rotation of the armatures and must not be so long that a the atmanttes' fartheu rotation away from the fuselage (see, e.~.. Figure 9) the propellors (8 and 9) mounted in the upper end (U-U) physically interfere with each other. (Slight overlap of tlu propeller arcs may be accommodated, however, by fore-and-aft staggering of the propellers.) The dimensions of 35 segments X. Y and Z together cannot be so long that the lower end (L-L) of the armature ~s.r .

the pontoons 22 and 23) fait to clear the waur during a water landing. That is, at maximum rotation of the ~rmat8res away from the fuselage (see, e.g., Figure 9), tlu pontoons (22 and 23) must be above the waur line of the fuselage. It will be additionally appreciated, referring briefly to Figures 6-10, that the mounting armatures (6 and 7) are shaped such that deployment of the stabilizing landing gear to any of the landing positions places the tower end of the armatures outboard of the pivot point, and therefore the forces encounured on landing and to open rather thaw to collapse the armaaues and landing gear. In accordance with these factors, in an aircraft according to this invention having the dimeosioos rexited ~ for a most preferred embodiment having the general configuration illustrated in Figure 1 (see page 13), by way of illustration and not of (imitation, the dimeosioos of the mourning armaaires would be as follows: Segment W, 44-48 in. (1.12-1.22 m); segmtat X. 19-24 in. (0.48-0.61 m): segment Y, 34-38 in. (0.86-0.965 m): segment Z. 28-32 in. (0.71-0.81 m); angle a (between W and X), 145 ° to 155 °; angle ~ (between X and Y), 115 ° to 125 °; and angle y (between Y and Z). .110 °
to 130°. The most preferable dimensions for this particular embodiment:
W, 46 in. (1.17 m);
X, 21.5 in. (0.546 m); Y, 36 in. (0.91 m); Z, 30-31 in. (0.77 m); a, 150°; ~. 120°: y, 120°.
Referring to Figure 40, a cross-section of the starboard wing (ref. Figure 3) is shown, where the mounting armature (~ is rotated fully inboard. so that the upper end of the mounting armature has merged with the fixed wing strucarre (1). Figure 40 shows a smooth aerodynamic surface provided by the now juxtaposed wing strucaue (1) and mounting armature (6). Within the armature housing, tix propeller shaft (81) is seen to extend from the starboard propeller (8) through a bearing (82) in the rear upper armature spar (71 ) to a bearing (82) in the forwud upper armature spar (70). The split flap (72) of the fixed wing saxion (1) is shown in raised position. and the leading edge slat of the main wing section (1) is shown fully retracted.
Referring to Figure 41, the two pivotal mounting armatures (6 and 7) are shown as in 2 5 Figure 38, except thu body armawres have been rotated around the pivot points (P) to be in the appropriate orieatadon for landing on a hard surface or rumvay. Rotation of the armawres to the position illustrated brings the stabilizing wheels ( 18) into position for landing. The wheels are swung out from the recesses in the pontoons (22 and 23, ref. Fig. 38), e.g., by mans of an actuating lever linked to one segment of a multilink actuating strut (not shown, discussed j~).
3 0 The propellers (8 and 9), in this orientation, are raised far enough above the wing so that substantially all of the arc of each propeller is above the wing. 'Ibis is advantageous for takeoff and landing attempts, because the propeller blades in raised position are less likely to encounter debris from the ground ark the propeller wash is directed over the control surfaces of the tail secuon.

.37_ Referring to Figure 42, the two pivotal mounting armatures (6 and 7) are shown as in Figure 38, exctptttrat both armatures have been rotated uound the pivot poima (P) to be in the appropriate oriernadon for landing on water, i.e., the pontoons (22 and 23) have been rotated into the appropriate position, the stabilizing whetis ( 18) have been retiracted, and the propellers (8 and 9) have bean raised to their maximum distance above the wing. In this orietuation, the propellers are shielded by,the wing from water spray, and the pmp wash is conducoed more directly over the control surfaces of the tail section. The increased downward lift caused by the prop wash over the tail sxdon partially counteracts the undairabk forward (nose-down) pitch that results from raising the thrust line. It should be recalled, however, that even though the thrust line is raised by rotation of the armatures, the cxrna of gravity does not change appreciably, since the mass of the engines remains below the wings, in the fuxlage.
Referring to Figure 43, a cross-secd~ of the starboard wing (ref. Figure 1) is shown.
where the mounting armature (6) is rotated partially outboard, so that the upper end of the mourning armature is raised above the fixed wing strucutre ( 1 ). W itlun the umature housing, the propeller shaft (81) is seen to extend from the starboard propeller (8), through a bearing (8Z) in the propeller nacelle bulkhead ( 112), through another beuing (82) in the rear upper armature spa (71 ), to a bearing (82) in the forwud upper umaatre spar (70). A
propeller drive pulley . . (83) is aaached to the propeller shag (81) and is turned by a propellor drive beh (84). which extends down to a pivot transfer drive pulley (unnumbered) aaached to a pivot transfer drive 2o shaft (291). A transfer pulley (94) also aaacbed to the piva aa~fer drive shaft (291) is turned by a drive belt (99). The split flap (72) of the fixed wing section ( 1 ) is shown in a lawut~ed position, and the leading edge slat (14) of the main wing section (1) is shown fully extended.
The mounting armatures of the presern invention may be acwatrad by any conventional means that serve to rotate the armatures about their pivot . Prcssuro-driven (e.g., 2 5 hydraulic, air) or screw~riven rods, for instance, that are set transversely in the fuselage and zee exaaded 6aizoncally to push the lower ends of the armsotutes away from the fuselage may by utilized, or gar~drivea pivots (P in Fig. 42) may also be employed. These mechanisms, however. have diaadvat>uges relating to the pt~ecision with which the a:mantte extension can, be controlled sod relating to the abaoc~ion of landing stresses.
3 0 The preferred actuator mechanism for extending and raracxing the pivaally mounted armatures according to this invention is a multilinic xtuator strut such as is depicted in several of the frontal elevation drawings discussed previously. (See, for example, items 280 and 281 in Figures 6. 7. 8. 9 sad 10.) Reftrring fast to Figure 9, in which the multiiidt xtuator struts 1280 and 281) are at their fullest extension, the struts zee seen to form (with the fuselage and thr 35 armatures) an amngemetu of two bxlc-to-bxlc 4-bar lidtages.

For each multilink actuator strut, a series of four rectangular links, connected end-to-end and togeth~t measuring the proper length to achieve the maximum desired outboard rotation of the mounting armatures, is attached at one end to the fuselage and at the other end to the lower end of the mounting armature. These connections leave three joitus in the series of four links between the fuselage and the mounting armature. A fifth link is auached at one end to the center joint in the 4-link series and is attachod at the other end high on the fuselage, so that the fifth link, the fuselage and the inboard two links of the 4-lint series form a 4-bar linkage. Two hydraulic (pictured) or screw-driven actuators are conned to the 4-link series so as to permit collapse (independently) of the outboard two links and the inboard two licks at the unbraced joints. Hy collapsing the inboard two links, an intermediate positioning of the armatures is achieved (see, Figures 6, 7 and 8); and by collapsing both the inboard two links then the outboard two links, the entire 4.-link series is folded imo the fuselage (sae, e.g., 280 and 281 in Figure 35), and the armatures are fully retracted.
The links of the multilink actuator struts will be sized to provide the exact positioning of the armatures necessary to deploy the desired configuruion of landing gear or propeller position. Collapse of o~ or both of the 4-bar linkages of the multilink actuator struts will provide automatic "stops" to the mounting armature rotation, eliminating the need to calibrate the pressure or screw-driven components of the actuator system.
2 0 A further innovative feature of preferred aircraft according to the invention is the incorporation of compound landing gear that enable the aircraft to be modified in flight for landings on a variety of surfaces (waur, hard surface, snow). Prior to this invention, them were no aircraft capable of safe landings and takeoffs from all of water, tarmac and snow, and certainly no aircraft that could be modified to land on any of those surfaces, at the option of the 2 5 pilot, while still in flight.
Aircraft incorporating the compound landing gear described herein will not only have the capability of landing on many surfaces, they will realize additional advan<ag~s from the particular design of the compound landing gear. For example, the compound landing gear of the present invention is expected to provide more efficient transmission of the inertial load to 3 0 the ground on hard landings. In addition. the utilization of slti-type gear thu may be retracted to be substantially flush with the fuselage is expected to provide a sboclc-absorbing effax in the event of a "wheels-up" landing (belly landing). Also, having the primary landing gear descend from the fuselage requires shorter landing gear mounts (compued with wing-mounted landing gear) which have a lower bending moment and are thus less apt to collapse from incidenul !octal loads, such as from tight radius turns a coo high a speed, la~inga with incorrxt drift correction, .or even collisions with ground vehicles.
'The compound aircraft landing gear of the present invention include three eomponems:
A) a forward landing gear component positioned forward of the ~r of gravity of the aircraft, substantially completely rea~actable into the fuselage, including integrated steerable siti and sceerable wheel subcomponet~;
H) a main central landing gear componeat, substantially completely retractable into the fuselage, including integrated skis and stxrable wheel subcomponetm. exh of which may be deployed to a point 8-13° (preferably 10-11 °) aft of the center of gravity of the level aircraft sad which, wtua retracted, assist in foctnuion of (or retract to form) a step in the fuselage at a point 8-13°
(preferably 10-11 °) aft of the center of gravity of the kvtl aircraft; and C~ a latrral stabilizing gear component comprising two bilaterally situated stabilizing members, each of which may be deployed on either sib of the aircraft t0 a point 8-13° (preferably 10-11°) aft of the comet of gravity of the level aircraft and substantially aligned with the main ceaaral landing gear.
and each member including integrated pontoon and wheel subcomQoneats.
The subcomponcnts of each component of the compound landing gear will be mwated in such a way that each of all the w6ee1 subcon>ponents, or all the ski subcompooems, or all the pontoon subcomponezns will be separately deployable to act as the primary laadiag gear for the aircraft, thu is, deployable to a position where the wheels, or the skis. or the pontoons becoate the lowest points of the level aircraft with respect to the ground (i.e., the points of cotuatx with the ground during s landing operation). Preferably. the forward and rosin cemral landing gear will be mounted in such a way thu whoa fully reaacued the shi-type gear will nestle into the fuselage opatiag through which the gear are deployed, and the bottoms of the atria will be substantially Hush with the outer surfacx of the fuselage. thereby eliminating the need for enclosing nose and gear bay doors. (Ses. Figure 44, position of skis 29;
Figure 50, position of skis 147.) Most preferably the subcomponents of each landing gear component will be integrated in such s way that, wherever possible, full depfoyu~ of one aubcompooenc will 3 0 automuically prevent full deployment of another subcomponent, so that no two sets of landing gear may be inadvertently deployed to their fullest extent and become, collectively, the primary (lowest deployed) landing gear for tl>e aircraft. The moat preferred embodiments will, howevrr.
permit coordinated xtion of the subcomponems where it is sdvaarageoua, for example, in providing ski-type landing gear thu can be raised to a level just slightly above the lowest point of the tires of the wheel gear, which is the best configuration for landings on intermittent snow-covered and cleu hard surfaces. (See, Figures 46 and 57.) As described below and with reference to the drawings, aircraft incorporating the compound landing gee of this invention ue uniquely serviceable anti safe.
Figures 44, 45, 46, 47, 48 and 49 illustrate the deployment and operation of a preferred forward lording gee component of a compound landing gee according to the invention. The same structural members are shown in each of these figures at different stages of deployment.
The reference numbers for each of the members ue the same from figure to figure.
Referring to Figure 44, a forward loading gear asxmbly is shown having the esxntial forward landing gear component functionalities, namely, full retractability within the fuselage (300) of the aircraft, sepuate deployability of either wheel or ski subcompoaents, and steerabiliry of the skis and wheels once deployed. As illustrated, the forward landing gear component is comprised of members for positioning (i.e., deploying of retracting) the wheel gee and ski gear, members for acntating tht positioning of the gee relative to the aircraft, members for pasicioaing the ski gear subcomponem relative to the wheel subcomponera, and (preferably) numbers for absorbing landing forces (i.e.. one ~ more shock absorbeca or springs). The neural steering mechanism has been omitted for the sake of clarity. Also, a braking mechanism will typically be included but is not illustrated here for the sake of clarity.
Referring again to Figure 44, the subcomponeats of the forward landing gee are embodied in a sceerabk wheel (21) (or, alcernuively, two stxrabk whoela), preferably having a pneumatic tire, and two skis (29, port ski only is shown), connaxed to the front wheel ask (208) by a front ski actuacoc link (204). which connats to each ski a a pivotal mount (209).
The whxi (21 ) of courx turns freely on its ask (208). but the ski pivotal mavnta (209) have stops (na shown) that win limit the arc that can be described by the skis, to prevent the skis 2 5 from ranting so far forward or backward that the aircraft can nose into the scow ~ bosom out.
during s ano~w land'rog.
The ask (208) of the fmnc w6x1 (21) is connected by a tubule stewing column (316) (or shaft) to a steering conaol plate ( 193). A swing-out mounting cylinder (230) nets as a housing fot the stewing colunm (316), within which the column is freely rotatabk by accuuion 3 0 of the steering control plate ( 193). The acatal staring mechanism, through which the stewing control plate ( 193) is auo<d. is not shown here. but prefwably the stewing mechanism (e.g..
steering cables or simile trn;chanism (ref. Fig. 60)) is attached to the stewing control plate ( 193) in such a way that the control plate ( 193), and ttrerefore the frotu wheel (21) and skis (29), become steerable only when they ue lowered for Landing: That is, the steering column 3 5 1316) can be rotated within the swing-out mounting cylinder (230) only whey the mounting cylinder (230) is swung-out to as approximately vertical orientation with respax to the aircraft.
When the swing-~uii mounting cylinder (230) is rotated to a substantially horizontal position with respect to the aircraft, as shown in Figure 44, the steering mechanism, preferably, will not be able to actuate the steering control plate ( 193) or otherwise cause the forward landing gear (28, 29) to swivel.
A ski deployment actuator (205) is pivotally attxhed at one end (206) to the staring control plate (193), and pivotally attached at its other end (207 in Figure 45) to the front sri actuator link (204). With these attachments and links, the front sici acatacor (205) will turn with the steering control plate ( 193), whxl (21 ) and skis (29); furthermore, the actuator (205) at this position allows the differential deployment of either the whxl gear (21) or the ski gear (29), as shown in Figures 48 and 49. The front slti actuator (205), as well as the other actuators in the landing gear assemblies, may be povve:~ by any suitable means, dtpending on taanufxauer's preference. Hydraulic cylinders, air cylinders. eia~ screw jxirs and eves hand craahs are all known for this sort of mahanical task, It will also be appreciated that although the foregoing description discusses single lilts and actuating arms, certain of the members described may advantageously be iattalkd in pairs. For instancx, it is mentioned that two sltia (29) are typically (and preferably) employed in the forward landing gear component; and accordingly two accuuor links (204) may be employed (iasttad of a single. U-shaped acutator link connxting both skis and pivotally mounted around the from wheel axle (208)), which, in turn, 2 0 would necessitate dual front ski actuators (205).
The forward landing gear (21, 29) and associated links and steering asxmblies described previously and as mounted in the swing-out mouaring cylinder (230) are coa~cted to the fuselage (300) via a front gear suspension lids ( 190) and a front gear connecting link ( 197) thu is further pivotally conax~ed to a front gear actuator link ( 198). The suspension link is 2 5 pivotally attached to the fuselage 1300) at one end ( 191 ) and pivotally attxhed at its other end ( 194) to the upper end of the swing-out mounting cylinder (230). The mounting cylinder (230) has a fm-like mounting appendage (317) projcaiag generally perpendiatlarly from the cylindrical dousing for the tubular staring column (316), extending diraxly aft when the mounting cylinder is in an upright (vertical) orientation. The front gear correcting link ( 19'x) is 3 0 pivotally attached at one end ( 195) to the swing-out mounting cyiinda (230) at a pivot on this mounting appendage (317) and pivotally attached at its other end (200) to the front gear actuator link ( 198), which, is rata, is pivotally attached to the fuselage at a pivot ( 199). The front gear acwator link ( 198) also provides a pivot attxhmcnt (203) for a front gear xtuator (201 ), which is pivotally attached to tla: fuselage as icy ocher end (202). The mounting appendage (317) also prw~a a pivotal m~in~g point (196) for a shock absorber or spring (189), which is pivaally aaached at its otheE end (192) to the fuselage (300).
Hy reference to the foregoing description and the drawings (Figure 44-49), it will be appreciated that actuation of the aforementioned series of linkages causes the swing-out mounting cylinder (230) to rotate generally in the sagittal plane of the aircraft (i.e.. the plane including the centerline and dividing the aircraft into symmetric halves), thus deploying or retracting the forward landing gear (wheel (21) and skis (29)). Furthermore, shortening of tlu front ski actuators) (205) deploys the skin (29) over the front wheel (ZI) (see. Figure 49).
During extension at retraction, the shock absorbetlspring ( 189) remains at its full length, since it does not support say of the weight of the aircraft. (See. Figures 44, 45 and 46.) In couching down for a Landing (Figure 47) and while operating on the ground (Figures 48 and 49), the front gear actuator (201) remains at its fully extended length, and the front gear acata~tor link (198) does not rotate, so that the connecting link (197) holds its position. and the shock absorber/spring ( 189) compresses and dxompresses as the landing or taxiing load varies.
To position the skis (29) for operation on a snow-covered surface, the front ski actuator (203 is extended. which rotates the front ski actuator link (204) about the from wheel axle (208). (See, Figures 48 sad 49.) On surfaces completely covered with snow it is desirable to position the skis (29) below the wheel (21) to climiaate drag from snow accumulating in front of the wheels, however during operation on surfaces where snow only partially covers the grout it is desirable to position the skis so that the tires of the wheel (21) exceed slightly below the skis (29), so that the aircraft rides up oa the tires where there is no snow but rides on the skis (with the wheels providing minimum drag) where the snow covers the ground. In order to raise or lower the skis (29) this small amwnt relative to the wheel (21), the front ski actuator (205) is raraaed slightly from its full extenai~. which rotates the support (204) and lowers the skis 2 5 (29) aliglttly.
Figures 30, 51. 52, 53. 54. 55. 56. 58, 37 and 59 illustrate the deployment sad opaadon of a prefecrod main oeaaal landing gear compost of a compound loading gear according to the invention. The same swcauat n>embers are shown in each of these figures at different stages of deployment. The reference number for each member is the same from figure 3 0 to figure.
Referring to Figure 51, a main cxotral leading dear assembly is shown having the essential main central landing geu componem futrctionalities, namely. full retracxability within the fuselage (300) of the aircraft sad recractability to form a step in the hull (necessary to permit takeoff from water). separate deployability of either wheel or ski subcomponents, sad 35 steaability of the wheels once deployed. Ac illustrated. the main cxnaal landing gear ??316-13D
r43-component is comprised of members for positioning (i.e., deploying or retracting) the wheel gear and ski= gear. ~mbera for acwuing the positioning of the gear relative to the aircraft, members for positioning the ski gear subcomponent relative to the wheel subcomponent, and (preferably) members for absorbing landing forces (i.e., one or more shock absorbers or springs). The actual staring mechanism has been omitted for the sake of clarity. Also, a braking mxhanism will typically be included but is not illustrated here for the sake of clarity.
Referring to Figure 50, a saxional side elevation of the midsection of an aircraft according to the invention is shown, illustrating the general positioning, within the fuselage (300) and fated wing section (1), of the major systems std structures, e.g., a wing extension panel (4) sad associated structures (unnumbered), the engines (in silhouette, 25 and 24 (partial)), the lower end of a port pivotal mounting armature ('n including a pontoon sxdon (23). The approximate position of the aft-most passenger within the aircraft is repraeated by the seated human figure (unnumbered). Figure 50 shows the position that the main skis (147) occupy in the fuselage (300), and shows the position that the arasature (?) and pontoon (23) occupy in the fuselage, when the aircraft is configured for cruising flight.
(Cf. Figures 3 and 9.) Full recaction of the main cxawal landing gear and of the mounting armacura brings the main skis ( 147), a main wheel hatch ( 148) and the poatoot~ (23) of the mwnring armatures into . . alignment. flush with the fuselage (300). creating a smooth outer surface.
In the preferred embodiment illustrated, it will be noted thu complete retraction of the skis (147) brings the nose 2 0 of the skis up into the fuselage (300), forming a slight notch ~ mini-step (arrow) in the fuselage, below the water line. Advantageously. this hatch helps to ventilate the hull when the aircraft is on the water, and it helps reduce the suction of the water that moat be overcome in order to take off from the water.
Referring to Figure 51, the same view of the aireraft'a midaectian as in Figure 50 is 2 5 shown, except that the outermost sections of the fuselage (300), as well as the main skis ( 147).
the main wheel bath (148), and the fully revacted mounting srmaarrc ('n and pontoon (23).
have been rezd~ transparent, and except for the fuselage (300) these components are repr~emed by broken lines ~ . - . ~. The lower line of the fuaeiage (300) is shown by a dotted line (....) where it is covered by the pontoon (?.3).
3 0 The main cenQal landing gear component as illusuued in Figure 51 is comprised of one or two (preferably two, as picwred, e.g.. in Figure 52) whaels (20) with (preferably) poaunuic tires, two skis ( 147), one or more shock absorbers or spring suspension members ( 129), one or more powered actuuors (hydraulic or air cylinders, or eletxric screw jacks, or similar apparatus) ( 141 ), and various connoting and supporting meaoba~a.

The main wheels (20) are rotatably mounted on a central ule assembly (Z10 in Figure 54), to which is attached.a brake system (not shown). The ule assembly (210) is connaxed via a steering column (not shown) to a main gear steering control plate (220) pivotally housed in a swing-out main gear mounting cylinder (133), in a similar manner to the frotu landing gear assembly (see, Figures 44-49). The main gear mounting cylinder (133) is also equipped with a rearward~atending fin-likc mounting appendage (318) fuel to the main gear mounting cylinder ( 133), to which a main gear connecting link ( 13'x, a main gear suspension link ( 130) and (preferably dual) shack absorbers/springs (129) can be pivotally attacZxd, i.e., at pivm connexions 135, 134, and 136 (Fig. 51), respectively. As in the forward landing gear component illustrated in Figures 44-49, the steering mechanism (not shown) for the main central landing gear wheels (20) will be conna~d to the steering condrol plate (220) so that the mahanism is engaged oNy when the swing-out main gear mounting cylinder (133) approaches a vertical (deployed) orientation with respect to the c~erline of the aircraft.
The main gear suspension link (130) is pivotally attxhed to the fuselage (300) at a pivot connection (t31). The shock absorbers/springs (129) are pivotally aaachcd to the fuselage (300) at a pivot connxcion ( 132). The main gear connecting link ( 137) as illusuated is Figure 51 is a tuning fork-shaped member which extends forward from its pivot connaxioo ( 135 on the mounting appendage (318) to a main gear actuating link (138), where it is pivotally atmch~ed at a pivot comaxion ( 140). The main gear actuating link ( 138) is pivotally aaac6ed to the fuselage (300) at a pivot connexion (139). A main gear aexuator (141) is also aaached tn the main gear actuating link (138) at a pivot coonaxion (143) and is pivotally atrached at its opposite end to the fuselage (300) at a pivot connection (142).
It will be appreciated that acxuadon of the aforementioned series of linkages causes the swing-out main gear mounting cylinder (133) to rotate generally in the sagiaal place of the airaaR (similarly to the mounting cylinder (230) of the forward leading gear component.
described syp~, thus deploying or retracting the main wheels (20). See. e.g., Figure 54, which sbvwa the main wheels (20) and the associated main cemsal gear strucnuea fully deployed.
During extension sad retraction, the shock absorbers/springa (129) remain at full length.
3 0 since they do na support any of the weight of the ainxaft. In touching down foc a landing and while operating on the ground (Figurts 54 and 5~, tlx main gear acatator (141) remains at a feed euea~ion, and the main gear acntating link ( 138) does not rotate, so that the main gear connecting link (137) holds its position, and the shock absorberslsprings (129) compress and decompress as the landing or tuiing load varies. The shock abaorbetslaprings (129) operate in 3 5 the same manner to absorb landingltuiing toads during snow landings, because the main skis (147), as more fully described j~, are connated to the same main gear connecting link (137).
This latter ~fa~t leads to,a further safety advantage of aircraft employing the compound landing gear disclosed herein: As can be seen with reference to Figures 50 and 51, the main skier (147) are the lowest part of the fuselage when in the fully retracted position:
however, even in the reu~acced position, the arrangement of the landing gear connecting and axuatang strucauet described above permits forces applied to the sltis to be transmitted to the shock absorbers/springs (129). Therefore, for water landings but more importantly for "wheeler-up"
landings on a hard surface (i.e., where the pilot either cannot or forger to deploy landing gear), the portion of the fuselage to come in first with the ground is advantageously constructed to take more punishment than the rigid fuselage of conventional aircraft. This feature, accordingly, not only improves the safety of the aircraft from tIx passengers' standpoint but improves the likelihood that the aircraft will suffer minimal struxural damage and will na be totally lost after this type of landing.
The skis ( 147) of the main central landing gear component are mounted on the main gear conaating link ( 137) via forward and rear ski support arms ( 144 and 145) and main sld connxting arms ( 149). Referring to Figures 52 and 53, where these eare more ckuly seen, the forward and rear ski support arms ( 144 and 145, respectively) are pivotally attxhed to the' main gear connaxing tinlc ( 137) in stepped recesses of the forward end of the member.
These stepped recesses permit the ski support arena ( 144 and 145) to fold flat against the base of 2 0 the train gear connxaag link ( 137), when the skier ( 147) are in a fully retraxed paaiti~ as shown in Figure 52. The forward ski support arms (144) are generally triangular in shape. with two pivotal connaxiont4 (213 and 214 in Figure 53) along the base to the main gear connecting link (137), and a biaxial pivot connexion (150) at the apex to the main slci connecting arnti ( 149). As beu illustrated in Figure 53, each rear sti support arm ( 14~ is generally rectangular in shape (ref. Figure 5'~ and hat pivot connaxio~ to the main gear conneaiug link (13'n at one end and a pivotal connexion at the opposite end to a V.shaped double axle member (238).
through which esch rear slci support arm ( 145) is coaneaed to a main sill coooexing arm ( 149).
One arm of the V-shaped double axle member (238) is pivotally aaached to the rear sri support arm ( 145); the other arm of the V-shaped double axle member (238) extend:
through the main 3 0 slci connxting arm ( 149) and forms a pivot connection ( 150) about which the main shi .
connecting arm ( 149) pivots. The relative angle of the arntt of the V-shaped double axle member (238) is such that the lower surfact of the sitis ( 147) are cauaod to be horizontal to the ground when the assembly is fully deployed and are caused to subataarially match the angle of the fuselage when the assembly is fully retraaed. The base of each main ski connecting arm 3 5 ( 149) is pivotally attached to a sri ( 147) by pivot connexioat ( 152) to flanges on the upper -4b-surface of the ski ( 147), as shown in Figure 53. Also shown in Figure 53 are screw-driven ski positioning ~ato'rs (215 and 216) for extending the skis (147) from their fully retraced position (see, Figure 52). The rear ski support arm actuator (215), which is pivotally aaachCd to the support arm as shown (239), pushes the rear ski.support arm (145) away from the main gear connecting link (137), which forces the skis (147) down and away from the fuselage.
Extension of the forward, ski support arm acarator (216), pushes the upper corner of the forward ski support arm (144) away from the main gear connecting link (137), thereby lowering the biaxial pivot connatioa (150) and causing the position of the main ski connoting arm (149).
and thus the main skis ( 147), to change by rotati~ about the pivot conna.Ki~
( 151 ) to the V-shaped double axle member (238). It will be appreciated by reference to the foregoing description and the drawings (esp. Figures 51. 52, 53, 55, 57 and 58) that by coordina~oed extension and retraction of the ski positioning actuators (215 and 216), the main skis (147) can be raised and lowered through a wide range of positions relative to the fuselage.
Although na critical to the invention, the various members comprising the maid central landing gear componem may be shaped and constructed to provide additi~al flotati~ elemaus, lending an additional feature to the multifunctional landing gear component.
As picwred in Figure 52, for instance, the main ski comating arm ( 149), rather than being fabricated as a solid shaft ~ bar, has been shaped to fill the space bavveen the fully ren~cxed skin (147) and the flu-folded forward and rear ski support arms ( 144 and 145). Thus shaped, the main ski 2 0 connecting arm ( 149) may be fabricated (without compromising its stru~rral strength) to be hollow, with the hollow compartment being watertight or filled with a buoyant foam. The main ski connecting .link ( 137) pictured in Figure 52 may likewise be fabricated with hollow compartments for buoyancy. The bay in the fuselage which houses the main central landing gear component prtfenbly will na be designed to be watertight, since this would significantly complicate the design and sharply raise construction costs. Accordingly, wbea the aircraft is on the water, the bay will be exposed to water. and any additional flotation elements such as the buoyant c~aectiag arm (149) will improve the seaworthiaesa of the aircraft.
Refatiag briefly to Figure 55, a cross-sectional aide elevation of the midsection of an aitcraft equipped with the prefaced main central landing gear component of this invention is 3 0 shown. and the landing gear arc deployed for a snow landing.
To position the skis for operations on snow~overed surfaces, the car ski suppocc arm positioning actuuor (215,in Figure 53) is extended, which rotates the farvvard cad rear ski support arms ( 144 and 145) out from the main gear connecting link ( 137). The ski support arms ( 144 and 145) position the main ski connecting arnos ( 149) so that the pivot line ( 152) of the skis 3 5 ( 147) is near that of the main wheels (20). Adjustment of the level of the skis using the forward ski support arm positioning actuator (216 is Figure 53) permits configuration of the main central landing geu for proper balance of the aircraft on all types of snow-covered surfs, in particular during lift-off and touch-down. On totally snow covered surfaces it is desirable to position the slcia (147) below the wheels (20) to eliminate drag from snow accumulating in front of the wheels. (See, e.g., Figure 58.) During operation on surfaces of intermittent snaw and clear surface, the skis are advantageously positioned so that the bosoms of the wheels (20) extend slightly below the skis ( 147) and the aircraft consequently rides up on the tires whore there is no snow but rides on the skis (with the wheels providing minimum drag) where the snow covers the ground. (See, e.g., Figure 57.) Referring again to Figures 54 and S5, it is importam to note that the main txatral landing gear component is positioned almost directly underneath the engines (24 and 25). In a twin~eagine aircraft, about half of the total weight of the aircraft is acxounted for by the engines. In conventional propeller aircraft, that load (i.e., the mans of the engines) is out on the wing strucaues; is aircraft as illustrated in Figures 54 and 55. the load is mounted inboard.
diratly over tlx larding gear. In a hard landing, the energy of the mass of the engines coming into contact with the ground is dissipated through the landing gear: and in conventional propeller aircraft that energy is translated through the wings to the fuselage and to the landing . _ . g~~ pi,~g a Ivt of stress on the wing strucwre. W ith an arrangement of engines and landing gear as illustrated in Figures 54 and 55, the energy of the mass of the engines at the velocity of 2 0 a hard (as opposed to a soft) landing is dissipated directly to the main cenaal landing gear component through the bosom of the fuselage, without putting those stresses on the wings or ocher strucnues of the fuselage. This is anocber feature which makes aircraft according to this invention more forgiving of commas pilot errors.
Figures 56. 58, 57, and 59 further illustrate the deployment sad operation of a lateral stabilizing gear compooea< of compound landing gear acacording to the present invention, comprising bilaterally situated stabilizing members, including integrated wheel and pontoon subcompooeaa. The drawings show a particularly preferred embodiment, wherein the stabilizing gear are integrated in pivotal mounting armatures also according to the invention. It will be recognized that less preferred embodiments of the stabilizing gear component may 3 0 alternatively be mounted under the wings ~ extended from the fuselage on separate supporting members. Employing the mounting armatures gives the stabilizing gear the added advantage of being fully retractable. as well as being coordinated with the paaition of the propellers.
Figures 56'59 present similar frontal elevations of an aircraft according to the invention.
showing the relative orientuion of the main central landing gear component and the lateral 3 5 stabilizing gear component, in each of four funding configurations.
Previously discussed .4g_ elements such as the propellers (8, 9), engines (24), belts, flaps (72), ailerons (10, 11). main skis (14'n, nnain wtiecls (20), etc. are provided for reference, however many previously discussed structures have been omitted from these views for the sake of clarity.
As illustrated in the embodiment of Figure 56, the pontoons (22 and 23) are integrally mounted on, and form the lower segment of, the pivotal mounting armatures (6 and 7, respectively). Thus, rotation of the armatures away from or into the fuselage (300) by means of the multilink actuating struts (280 and 281) deploys or retracts the pontoons (22 and 23).
Stabilizing wheels (18 and 19) are aaacbed to the pontoons (22 and 23) by wheel mounts of course permitting free rotation of the stabilizing wheels. The wheel mounts may be fixed or (preferably) retractable. In the embodiment illustrated, the pontoons are fabricated with recesses into which the stabilizing wheels ( 18 and 19) can be t~evxxed.
Exunsion or ret~ction of the stabilizing wheels (18 and 19) may be performed by nay suitable means (e.g., separate powered actuators); however, preferably the stabilizing wheels (18 and 19) are mounted, as shown here, so as to automatically extend or retract according to the rotation of the pivoting mounting atmacures (6 and 7), which is effected by means of statboard and port stabilizer actuating links ( 168 and 169, respectively) fixedly attached not one end to the respative stuboud and port muldlink actuating struts (280, 281), std pivotally attached at the other end to pivotal wheel mounts to which the stabilizing wheels ( 18 sad 19) are rotatably mourned. The stabilizer actuaaag links (168 and 169) are fixedly attached to the final (outboard-most) lilt of the 4-link series of each multilink actuating strut (280 and 281; ref.
description, ~, so that at intermediate extension of the multilink actuating struts (280 and 281), reaaaabie wheel mounts are forced down, swinging the stabilizer wheels (18 and 19) irno a deployed position.
(See. Figures 56, 58, 57.) When the 4-link series of the tmiltilink acwating struts are at full extension (Figure 59) or when the oucboud 4-bar linkage is collapsed (i.e., when the mounting armadua ue retracxod to the fuselage), the angle of the final link of the multilink acritatiag struts (280 sad 281) c6aoga, and the stabilizer acaracing lidca (168 and 169) are pulled upwards, causing the stabilizing wheels ( 18 and 19) to swing back iron their respoaive recesses in the pontoons (22 and 23).
The stabilizer wheels are preferably non-steerabk sad are on caster mounts, so that they 3 0 swivel to roll in any diradoa thu the aircraft takes, as soon as they are in c~tacx with the ground.
Each of the subcomponerns of the main central landing geu sad the lateral stabilizing geu (i.e., main wheels, stabilizer wheel, main skis, pontoons) moat be mounted in the aircraft so that when fully deployed, the center or pivot axis of the subcoatponern (e.g., hub of the wheel or pivot mourn of the ski) is positioned at a point 8-13°, preferably 10-11°. aft of the ~9-center of gravity of the level aircraft. Furthermore, when the lateral pontoon members are deployed (22-and 23 in Figure 59). the exposed underside of the fuselage (see.
dotted line in Figure 51) must form a step 8-13°, preferably 10-11 °, aft of the center of gravity of the level aircraft. 8y "level aircraft" is meant an aircraft where the fuselage is level fore-and-aft with respect to level ground, i.e., the longitudinal axis of the aircraft is pualkl to the ground. A
plumb line from the center of gravity of a level aircraft will be perpeadiculu to the centerline:
and the center of exh aft landing geu subcomponent, when fully deployed, must be fu enough aft of the center of gravity so that a first line, extending from the of the deployed landing geu subcomponent (e.g., the hub of the main or stabilizing wheel), parallel to the longitudinal axis of the aircraft that includes the center of gravity, to interact the transverse axis of the aircraft that includes the center of gravity, and a second line that is a plumb line from that point of iaterseccion of the first line and the transverse axis will form as angle of &13° and preferably 10-11 °. If the landing geu design caused ctx landing gear to be deployed focwud of the first line, the aircraft would be prone to rotating bah on its tail and never allowing the noac geu to touch down. If the landing geu design caused the landing gear to be deployed too far aft of the first line, the rotational force coming down on the nose gear during landing wouk be too great for the forwud landing geu (and possibly the nose section of the fuselage) to handle . . without damage. If a step in the fuselage is placed too far back, the drag of the water on the fuxlage will be too great to overcome, and the aircraft will not be able to take off from water.
Figures 60 and 6I diagram two passibk stewing mechanisms for the statable forward landing geu and the steerabk main central landing gear. In the mechanism of Figure 60, the main central landing gear and the forward (nose) landing gear ate stared by the same mechanism, with the nox gear additionally independently sseerabk by the ruddy pedals (229; R
- right, L ~ left). In Figure 61, the steering mechanisms for the nose gear and the main central gear are indThe coordinated mechanism of Figure 60 is preferred.
Referring to Figure 60, cable-and-pulley conneaiom are made betwan a steering xtuator plain (223) and the forwud geu steering contml pf~e (193: see, also.
193 in Fig. 49) and the main cxntral geu steering control plate (220; see. also. 220 in Fg.
54). The steering actuator plate (223) is driven by the steering control motor (224), which is connected to the 3 0 acatacot plate (223) through a geu box (225). An override hard crank steering control (226) is preferably provided in the event that the stewing control motor (224) biomes inoperative. The positioning of the steering actuator plate (223) is translated to the main cxntral landing gear via cables (221 ) connecting to the main geu steering conaol plate (223). Pulleys (222) ue provided to guide these cables (221 ). The positioning of the steering acxuator place (223) is 3 5 translated to the forwud landing geu via cables (227) connecting to the forwud gear steering control plate (193). Pulleys (222 and 235) are provided to guide the cable (227) appropriately.
The forward-gear steering cables (227) also coop around pulleys (237) rotatably feed to the rudder pedal connecting bu (240) in a slack-giving/slack-taking arrangen0ent, so that movements of the rudder pedal connecting bu (240) are also translated to the forward gear staring control plate ( 193).
Referring to Figure 61, a similu arrangement of cables and pulleys to the xheme of Figure 60 is shown, except the forwud gear steering cables (227) do not connect with the steering actuator plate (223), and therefore the forward (nose) landing geu and main central landing geu steering controls ue independent.
With the steering mechanism design shown in Figure 61, the pilot adjusts the main central landing geu steering angle by operating the steering control motor (224) (or the override handwixel (22b)) to compensate for or cancel the "crab" angle to which the aircraft is turned at takeoff or landing to compensate for cross-wind conditions, thus matching the angle of the landing geu to the direction of the rummy. The pilot also sets the same angle into the hose geu using the rudder pedals (229). Witb the steering mechanism design s6awm in Figure 60, however. the pilot sets both the main central landing geu and nose geu angle with the steering control motor (224) (or haadwhxl (226)). The rudder pedals (229) are used oNy to make fine . . ~j~~a~ to the nose wheel with respect to the angle already set by positioning of the main central landing geu. Pilots will recognize that the incorporation of steerabk forwud and main 2 0 central landing geu virtually eliminates the erects-wind limitation inherent is aircraft with conventional landing geu designs, espxialiy where this fore and aft steersble landing gear feature is combiru~d in an aircraft having the compound wing structure, dexribod previously, which can be acxivated to dramatically Iower the stall speed of the aircraft.
A 1/5 scale model of an aircraft according to the invention was coattrucced out of balsa wood with a styrofoam-filled core and a fiberglass shell. The model had the fuselage and wing configuracioo of an ai~'t as illustrated in Figure 1. and it was powered by two 2.2-horsepower. single-cylinder model airplane engines and props, mauated ~ the coda of armatwes (see, e.g., items 6 and 7 of Fig. 1) raised above the wings. The nu~del was suitable 3 0 for studying general flight chuacceristics on takeoff, landing and low speed cruising flight.
Remae-coruroiled flight of the model indicated acxxeptabk fiigtu petfonmsace (including rudder effeaivetuss at low speed) and good correlad~ to predicted paformana.
Two computer modeling programs were written, one to predict performatrce std une to predict stability of an aircraft based on input of data describing the size, weight, power and 3 5 configuruion of componetus. The programs were tested and verified using published data from extensive wind tunnel studies conduced by the U. S. Air Force. A computes model of an aircraft accordia~to the invention was then compared against a computer model of a "conventional" aircraft pauerned after several known production twin~agine or amphibious aircraft. The computer comparisons predicxed that the configuration of aircraft according to the invention having inboard-mounted engines reduced the power requirements by as much as 20~
over those of a conventional twin-engine aircraft. Additionally, aircraft according to the invention having the engine and drive system and the extendable wing system described herein had a single engine climb rate 120% higher than that of a conventional twin-engine aircraft model. In comparison to a conventional amphibious aircraft, presuming a single engirx mounted on a pylon above the fuselage, the computer model aircraft according to this invention had a maximum level cruise speed of 160 that of the conventional model.
Wind tunnel tests of small models of aircraft as described herein in various configurations (e.g., wings retracted, wings extended, cetmal landing gear deployed) were conducted and showed favorable aerodynamic characteristics in all configurations. In patticulu, desirable non-turbulent airtlaw was observed across the vertical and horizontal conQOl surfaces of the tail section when the main wing section was placed in and tear the stalled attitude.
Multi-purpose aircraft having a range of performance capabilities may be produced according to tl~ foregoing description using conventional materials and well known aircraft construction techniques. The major savca>tal components of prefaced aircraft according to this 2 0 invention are shown in Figure 62, which is an exploded perspative view of as aircraft similar to the embodiment illustrated in Figure 1. Moat of the structural members picatred in Figure 62 may be readily and preferably fabricated out of aluminum stock. e.g., by high-pt~essure water jet cutting. Most of the strucaues illustrated in Figure 62 have already been described and will not be further described beet. The reference numerals employed here correspond to the descriptions 2 5 ~yp~. With rapes to the primary structure of the fuselage, Figure 62 illustrates the modular design of the aircraft: The primary fuselage strvcntrr is formed by bolting a main fuselage saxion (300) including a tail section (310) etd-to-end with a forward cabin module (233) and.
optionally, with an intermediate cabin extension module (234). An upper cockpit assembly (3) and an upper cabin extension assembly (2) are attxhed to the forward sations of the fuselage 3 0 primary structure to provide a continuous cabin enclosure. As illustrated in Figure 4, the intermediate cabin extension module (234) and associated upper cabin assembly (2) tray be omitted during cocutruction of the aircraft to produce a shorter, lighter aircraft. Alternatively.
for a larger enclosed cabin space, wide-body upper cockpit and upper cabin extension assemblies (231 and 232, respectively) may be substituted during construction for the standard 3 5 upper cockpit std cabin extension assemblies (3 and 2, respectively). A
wide-body version of the aircraft, illustrated in plan in Figure 63, results. Thus, several different types of aircraft may be asseZnbled.in the sane; plant, without redesign of the primary strucaual components.
From the foregoing description, many different embodiments of aircraft i~orporating innovative feature uxording to this invention will be possible. All such embodies, including obvious variuioas of the particularly preferred designs disclosed herein. are intended to be within the scope of tlus invention, as defined by the claims thu follow.

Claims

CLAIMS:

1. ~A compound aircraft wing comprising:
a fixed wing section comprising a bilaterally symmetrical aircraft wing of a fixed length (span) defining leading and trailing edges and defining port and starboard halves, said fixed wing section being at least partially hollow, thereby defining an inner surface and an outer surface of said fixed wing section, said fixed wing section further being open at the port and starboard ends, thus forming port and starboard openings, a port wing extension panel comprising a forward port lift spar, a center port drag spar, and an aft port lift spar, which port spars are disposed in parallel relation and each spar being substantially the same length as said fixed wing section, substantially one-half the length of said spars being enclosed by and giving structural support to an outer skin so as to form a port aircraft wing extension section ending in a wing tip, said port wing extension panel being extendably mounted inside said fixed wing section such that said port wing extension panel is extendable through the port opening of the fixed wing section such that substantially all of the port aircraft wing extension section protrudes from the port end of the fixed wing section, said port wing extension panel further being mounted inside said fixed wing section such that said port wing extension panel is retractable within said fixed wing section such that substantially all of the port wing extension panel is enclosed by said fixed wing section, and a starboard wing extension panel comprising a forward starboard lift spar, a center starboard drag spar, and an aft starboard lift spar, which starboard spars are disposed in parallel relation and each spar being substantially the same length as said fixed wing section, substantially one-half the length of said spars being enclosed by and giving structural support to an outer skin so as to form a starboard aircraft wing extension section ending in a wing tip, said starboard wing extension panel being extendably mounted inside said fixed wing section such that said starboard wing extension panel is extendable from the starboard opening of the fixed wing section such that substantially all of the starboard aircraft wing extension section protrudes from the starboard end of the fixed wing section, said starboard wing extension panel further being mounted inside said fixed wing section such that said starboard wing extension panel is retractable within said fixed wing section such that substantially all of the starboard wing extension panel is enclosed by said fixed wing section, said port wing extension panel and said starboard wing extension panel being mounted in such relation that said port spars and said starboard spars are in interlocking juxtaposition inside the fixed wing section.

2. ~A compound wing according to claim 1, wherein a wing span of the compound wing is increased by up to 90-95%, compared to the span of the fixed wing section, when the port and starboard wing extension panels are fully extended from said fixed wing section.

3. ~A compound wing according to claim 1, wherein said port and starboard wing extension panels are mounted in said fixed wing section by means of rollers fastened to the inner surface of the fixed wing section.

4. ~A compound wing according to claim 1, wherein the fixed wing section has a dihedral of 3 degrees; the span of the fixed wing section is about 8 m; said port and starboard wing extension panels have no sweep; and a wing span of the compound wing with port and starboard wing extension panels fully extended is about 15.25 m.