US2816483A - Exhaust actuated missile exit door - Google Patents

Description

Dec. 17, 1957 R. T. JOHNSTON EiH-IAUST ACTUATED MISSILE EXIT DOOR Filed Oct. 6, 1952 EXHAUST ACTUATED MISSILE EXIT DOQR Robert T. Johnstomlacific Palisades, Califi, assignor to Northrop Aircraft,.1nc., Hawthorne, Calif, a corporation of California Application October 6, 1952, Serial No. 313,271

1. Claim. (Cl. 89-1.7)

This invention relates to rocket launching devices and more particularly to a rocket launching device in which rockets are mounted for firing from within a streamlined structure of an airplane, such as a wing tip pod or wing nacelle, in which a portion of the streamlined structure is indirectly moved by thrust of a rockets exhaust gas to provide a clear forward course for the rocket.

In military planes rockets are normally mounted on the underside of their wings with their axis parallel with the longitudinal center line of the plane. This method is objectional as it increases the frontal areas of the airplane and materially increases its parasite drag.

It is, therefore, an object of the present invention to provide a rocket launching device ideally suited for use with an airplane.

Another object of the present invention is to provide a streamlined structure completely surrounding a rocket and.

its associated launching tube except at such time as it is being fired and discharged from the above structure.

Another object of the present invention is to provide a movable surface ahead of a rocket launching tube, the surfacebeing movedupon firing of a rocket from the tubeby the rockets exhaust gas to a position in which it provides a clear course for the forward movement of the rocket.

Other objects and advantages of the present invention will be apparent from the following description forming a part of this specification, however, the invention is not limited to the embodiment herein described as various forms may be adapted within the scope of the appended claim.

Throughout the specification andclaim of the present application the Word rocket includes both guidedancl.

unguided reaction driven or self-propelled missiles.

The invention may be more fully understood by reference to the accompanying drawings, wherein:

Figure 1 is a perspective view of an airplane having wing tip pods in which rocket launching tubes having movablecover elements, of the type disclosed in the present invention, are incorporated.

Figure 2- is a front elevational view of the wing tip pod of Figure l showingthelaunching tube covers in their closed position.

Figure 3I- isa-sectionalview of the wing tip pod of Figure 2 taken on the line 3-3 thereof.

Figure 4 is a cross sectional view of the wing tip. pod of Figure 3' takenon the line 4'4 thereof.

Referring to Figure l a jet driven' airplane 1 is fitted with wing tip pods 2, their forward portion 3 being utilized for mounting rockets while engine fuel is carried in a plurality of generally cylindrical tanks in the aft portion 5 of the pod 2.

A bulkhead or fire Wall 6, comprising a circular plate of heat resisting material, is positioned between the fore and aft portions of the pod. The circular faces of the bulkhead are normal to the longitudinal axis of pod 2 and in this position effectively shields fuel in the fuel ire tanks 4 from heat which may be radiated from the exhaust gases of rockets fired from within the forward portion of the pods.

The forward portion 3 of the wing tip pod comprises inner and outer concentric generally cylindrical members 7 and 8, the members being joined at their forward ends to provide a streamlined-contour. The outer surface of the fore and aft portions of the Wing tip pods-are continuous, a streamlined structure is thus provided.

The outer cylindrical surface of the forward portion of the pod is provided with a plurality of circumferentially spaced generally rectangle shaped openings 9' when viewed normal to the surface of the pod. Threesuch openings are shown in the present embodiment, each provided with a cover or closure element 10 capable of closing the openings and maintaining a flush relationship with the outer cylindrical surface of member 3, shown by solid line construction in Figure 3. An aid in position ing and retaining the cover in its closed position is provided by a ledge 11 extending around a major portion of its periphery, in the covers closed position the ledge is'in abutting relationship with the inner surface of cylindrical member 8.-

The rocket launching tubes 12 as shown in the present embodiment are cruciform in cross section, each arm portion 13 providing a passageway for a fin member 14 of the rockets 15. The launching tubes are equally spaced circumferentially within the annular chamber 16 defined.

by the generally concentric cylindrical members 7 and 8, the axis of each tube being parallel with the longitudinal axis of the pod. securely held in position by means of apertures in a circular plate 17, said plate being positioned a short distance. ahead of bulkhead 6, the tubes are secured longitudinally to concentric members 7 and 8 by means of their arm portions 13. Tubes 12 extend forward from plate 17 to a-point' adjacent the aft end of covers 10, suf ficient clearance being provided between the forward end of the tubes and the covers to allow the latter to swing-inwardly, in a manner to be presently described. Conduits 18 coinciding with the aft ends of tubes 12, extend'rearwardly and laterally to exhaust ports 19 located in the side wall of the pod forward of bulkhead 6, to provide passageways 20-for the flow of exhaust gases. The passageways change from a cruciform cross section adjacent the launching tubes to a circular cross section a short dis tance aft of said tubes.

Additional rockets and'launching tubes, utilizing operating mechanism as disclosed in U. S. applications 303,381, dated August-8, 1952, and 804,351, dated August 14,- 1952', may be mounted within cylinder 7 and in'the space defined by cylinder 8 and arm portions 13 of adjacent launching tubes, respectively, asshown in Figured;

In the present embodiment rocket propelled missiles are fired from launching tubes 12' of the character-having radar or similar sensitive equipment mounted in their nose portions. It is imperative that their nose portions do not come in contactwith any structural elements, as

they move forwardfrom their'resp ective launching tubes, if the equipment mentioned above is to function properly.

To provide a free forward course'for a rocketthe' cover 10- is" mounted for movement'inwardlyfromitsclosed position. To this end pivot members 22 and 23 are provided, the above members are mounted between four sets of laterally spaced lugs which are secured to the inner surface of cover 10 and the outer surface of cylinder 7. Pivot member 22, which is generally H-shaped in configuration, extends between lugs 24 and 25 and is pivotally attached thereto by means of pins 26 which extend between each set of lugs, said lugs being positioned near the forward end of the cover 10. Pivot members The aft end of tubes 12 are 23 extend between lugs 27, secured to cylinder 7 approximately opposite the mid-point of the opening 9, and lugs 28 positioned on cover 10 near the aft end of the openings 9, the above members 23 are pivotally secured to lugs 27 and 28 by means of conventional pins. A pair of helical springs 30 are secured between a non-movable structural element of pod 2 and a lug 31, the latter extending generally at right angles to pivot members 23. Springs 30, which are under tension at all times, provide means for holding cover 10 in its closed position until acted on by an external force and for returning the covers from their open to their closed position. The cover mounted as described above, is movable from a closed position to a fully open position, the latter being shown by phantom construction in Figure 3. A stop 32 is provided on cylinder 7 to limit the inward movement of the cover.

Positioned in each passageway 20, directly aft of rocket 15, are actuating flaps 33 swingably mounted to move between a closed and open position, shown by conventional and phantom construction, respectively, in Figure 3. Flaps 33 are fixedly secured to hinge pins 34, the latter being mounted for rotary movement in bearings 35 positioned externally of conduits 18. An arm 36 is keyed to pin 34 and moves through an equal are as the flaps move between their open and closed position.

A bellcrank 37 is mounted in a bearing support 38 located on the forward side of plate 17. The bellcrank rocks about an axis normal to a plane containing both the longitudinal axis of a rocket 15 and pod 2, both arms of the bellcrank are also positioned generally in the above plane. A connecting member 39 extends between arm 36 and the aft arm 40 of the bellcrank, the member 39 being pivotally attached to the end portions of the arms by means of conventional hinge pins.

vA Bowden wire assembly 41 provided with attaching end portions 42 extends between the bifurcated end por tion of arm 43 of the bellcrank and the mid-portion of hinge pin 26 located adjacent cover 10. The Bowden wire assembly is positioned adjacent the outer surface of cylinder 7 and is attached thereto by means of a plurality of clips 44 to the wall of said cylinder.

A rocket is supported in firing position within its launching tube by means of a conventional launcher 45. A shear pin 46 retains the rocket in its tube and in a-fixed position relative to its launcher until such time as it is fired. The launcher contains an umbilical connection plug 47 by means of which electrical impulses, including impulses for firing the rocket are transmitted thereto, however, the particular type of launcher constitutes no part of the present invention, the type shown being illustrative only.

Diagonal slots 48 extend rearwardly in the surface of cylindrical member 8 from each corner of the openings 9, the above slots provide clearance for the rockets fins as the rocket moves forward from its launching tube.

In operation the three rocket propelled missiles 15 are loaded in their respective tubes from the forward end of said tubes, this operation is accomplished after the covers 10 have been moved to their open position. At the same time rockets are also loaded interiorly of cylinder 7 and between the arm positions of adjacent tubes 12.

Individual frangible plugs 21, positioned in the forward end of the launching tubes located interiorly of cylinder 7, preclude the flow of air therethrough prior to firing.

Upon the firing of a rocket the thrust from its exhaust gas exceeds 1200 pounds, this exceeds the thrust required to shear pin 46. Before pin 46 is sheared the thrust of the rockets exhaust gas impinging on flap 33 is sufficient to swing it from its closed toits open position. The swinging movement of flap 33 is transmitted to cover 10, through connecting member 39, bellcrank 37, and Bowden wire assembly 41, causing the cover to move from its closed position to its fully open position, in the latter position a clear forward course for the rocket is provided. Actual launching data discloses that the thrust of the rockets exhaust gas is more than adequate, in fact allows a good margin of safety, to move cover 10 into its fully open position prior to the shearing of pin 46. The same data discloses the thrust of the rockets exhaust gas is sufiicient to retain cover 10 in its fully open position during the rockets exit from pod 2.

From the above disclosure it is apparent there is provided a rocket launching device capable of accomplishing the various objects set forth above. While in order to comply with the statute, the invention has been described in language more or less specific :as to structural features, it is to be understood that the invention is not limited to the specific features .shown, but that the means and construction herein disclosed comprise a preferred form of putting the invention into effect, and the invention is therefore claimed in any of its forms or modifications within the legitimate and valid scope of the appended claim.

What is claimed is:

In an airplane having a leading edge surface, the combination comprising: a rocket launching tube mounted within the airplane and having a forwardly-facing open end; means defining a discharge opening in the surface aligned with said tube; a cover for said opening mounted on the airplane for swingable movement between a closed position wherein said cover constitutes an extension of the surface and an open position wherein a rocket fired from said tube can pass freely through said opening; resilient means urging said cover to said closed position; a conduit in the airplane rearwardly of said tube providing a passageway for exhaust gases of a rocket fired from said tube; an actuating flap swingably mounted in said conduit; linkage means connecting said flap to said cover to move the latter from said closed to said open position on the impingement of the gases on said flap; and detent means in said tube engageable with a rocket therein to retain the latter in said tube, said detent means being releasable by a predetermined thrust of a rocket being fired from said tube, whereby forward movement of a rocket is delayed until said cover moves to its said open position.

References Cited in the file of this patent UNITED STATES PATENTS 2,395,435 Thompson et al Feb. 26, 1946 2,445,235 Myers July 13, 1948 2,451,522 Uhl et a1. Oct. 19, 1948 2,470,120 Walker May 17, 1949 2,481,542 Schuyler Sept. 12, 1949 2,517,333 Motley- Aug. 1, 1950 FOREIGN PATENTS 804,838 France Nov. 3, 1936 924,013 France July 24, 1947

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