US1956823A - Wing structure - Google Patents

Description

May 1, 1934. E, B, CARNS 1,956,823

WING STRUCTURE I Original Filed June 15, 1929 2 Sheets-Sheet, 1

y 1934. E. B. CARNS 1,956,823

WING STRUCTURE Original Filed June 13, 1929 2 Sheets-Sheet, 2

l atentecl May 1, 1934 UNl'l'ED STATES PATEN E' FFifiE Cairns Development Company, Wilmington,

Del, a corporation of Delaware Application .lune 13, 1929, Serial No. 370,695 Renewed August 15, 1933 1d illairns.

My invention relates to improvements in aircraft structures and more particularly to the wing or airfoil structure of an aircraft.

My invention is particularly intended to give a strong rigid structure having a minimum weight. I accomplish this by a means which is extremely simple, in which there is no waste metal in any of the parts and in which there are no unnecessary structural elements.

My invention is further intended to produce a wing frame which tapers in width and thickness, that is, a double tapered wing and also a structure in which the structural elements taper in cross section, that is, are gradually reduced in cross section, and in which the structural elements are made lighter progressively toward the wing tips.

My invention is further intended to produce a structure which is easy to produce due to the simplicity of the parts, their availability in the open market, and which are also adaptable to commercial production on a quantity basis. In accomplishing these ends according to my invention the points at which the elements must be fastened are easily accessible thus allowing not riveting and eliminating the disadvantages of cold riveting. My invention further provides a structure in which the parts may be fastened to gether without weakening any of the elements.

These objects are attained by placing the inerbracing in such a manner that they represent he resultants of the stresses in a wing strucure. By this means 1' have eliminated all unnecessary elements. Carrying out this analogy, my interbracing represents the diagonals of cubes, the other edges of the cubes representing the various stress vectors.

" 'ing more particularly to the drawings:

Figure 1 represents a perspective view of a broken portion of my structure:

- re 2 is a view taken at 2-2 of Figure 1; -re 3 is a View taken at 3-3 of Figure 1;

Figure 4 is a View taken at 4 4 of Figure 1;

Figure 5 is a broken detail of unasseinbled brace elements;

Figure 6 is a detail of a lock washer;

Figure '7 is a modified form of rib structure and fastening;

Figure 8 is a side view partly in cross section of a spar member; and

' re 9 is a perspective view showing the wing cover .ig.

in Figure l the 11., per spar members 1 and the lower spars 2 are held in spaced relationship by means of the interbraces 3. These spars are of a generally angle bearn cross section and are of tapered construction tapering both in width of the langes and in thickness of the metal. They also taper in their spaced relationship gradually approaching each other as they approach an exty of structure. The interbraces 3 are prefly z-beams but may be of other suitable type. ey are formed with ends 4 as shown in Figure 5. may easily be done by trimming oil a portion of a flange and then bending the end to the form shown, or the braces may be cast or worked in any other manner to this form. The ends of these interbraces are designed to fit in one another as shown at 5, Figures 1 and 4. The inner flange 6 is placed under the edge of the spars 1 and 2 as shown in Figure 3. These interbraces are fastened together by rivets at '7, and the two overlapped ends .are fastened to the spars 1 and 2 by means of the bolt 8. The angles of the upper and lower spars open into the structure. The angle of the sides of the spars is such that both ends of the interbraces lie flat against the sides of the spa-rs. The nut 8 on the bolt 8 is held fixed by means or the washer 9, a plan view of which is shown in Figure 6. This washer is bent so that it fits in the angle of the spars 1 and 2 and is perforated on each end at 10 which allows the boi to pass through it. After the nut 8 has been screwed tight on the bolt 8 the tabs 11 are bent up holding the nut in fixed position.

The cross ribs 12 run transverse to the spar members. ihese ribs may be tapered in all dimensions as they approach an extremity of the structure, for instance, the leading or trailing edge of a wing. The cross ribs arev cut away as shown at 13, Figure 2, so that the spar members may be recessed in it and a snug fit thus made. The ribs are fastened to the bolt 8 by means of the bolt 14 which passes through the rib and the hole 15 in the bolt 8 situated inside of the channel. Bolt 8 may be cut away as shown at 16, Figure 4, eliminating a certain amount of metal which is unnecessary.

Figure 7 discloses a modification of a rib and method of fastening in which 17 designates a T- beam type of rib. This rib is cut away at 18 allowing it to fit snugly over the spar member and is fastened to the spar by means of bolt 8. However, in this type of construction the web of the rib may be placed within the recess 16 of the bolt 8 and held fast by passing the bolt 14 therethrough.

Figure 8 shows the tapered construction of the spars 1 and 2, l9 representing one flange showing its taper towards the tip and 20 designating a cross section of the other flange showing that this cross section also decreases toward the tip.

It can be seen from the structure disclosed that the elements have all been simplified to an extreme degree and that they are of such a type and design as to facilitate easy manufacturing on a commercial scale. Further it can be seen that the methods of fastening these elements together are such that they are not weakened. The ribs and interbraces are fastened to the spars in such a manner that only a minimum number of holes are necessary in the spars. For this reason the spars may be made lighter inasmuch as it is not necessary to use extra metal to counteract the weakness due to the holes necessitated in fastening the elements to the spars. The interbraces are fastened together separate from the spar. The ribs are fastened to the same bolt which fastens the interbraces to the spar.

My structure is an extremely simple one to assemble for the interbraces may be easily riveted together at a point distant from where the struc ture is to be assembled. These braces, spars and ribs may then be quickly assembled by means of a single bolt at each point of intersection. I have been able to obtain such a simple structure by resolving all of the stresses and using interbracing only as the resultant of these stresses. In this way I have a statically determined structure where every stress is taken up at the proper point and distributed over the entire structure. I have thus been able to obtain a light rigid structure of great strength and with locked stresses.

My structure may be covered in the manner disclosed in Figure 9. I have shown in this figure the structure and covering adapted to a wing but it is, of course, applicable to any wind-exposed surface. The covering consists of the sheet or sheets 21, 21 21 21, 21 These sheets are overlapped as shown at 22, the overlapping of course, being towards the trailing edge. The sheet which at the point of overlapping is placed underneath is placed over the sides of the spars 1 as shown at 23. The edge of this sheet has tabs of which one is shown extending at 24. These tabs are bent under the edges of the spars l and 2 holding the sheet firmly in place. The upper overlapping sheet is then fastened by means of rivets or otherwise to the undersheet as shown at 25. The covering sheets may also be fastened if desired transversely to the ribs 12 by screws preferably of the type shown in my copending application Serial No. 179,987, filed March 31, 1927. In this manner a strong, tight wind-exposed surface is obtained without the necessity as is the usual case, of weakening the structure members by drilling them for the fasteners with which to hold the covering to the frame.

To those skilled in the art it is obvious that my structure is adaptable to many other portions of an aircraft besides that of a wing structure. The structural design of certain elements may also be changed without departing from my invention. I, therefore, do not wish to be limited by my specification and drawings, but only by the prior art and the appended claims.

What I claim is:

1. In an aircraft structure upper and lower tapering spars in staggered relationship, diagonal interbraces connecting said spars, and upper and lower tapering ribs in staggered relationship connected to said spars and interbraces.

2. In an aircraft structure upper and lower tapering spars in staggered relationship, diagonal interbraces having ends meeting at said spars, and upper and lower tapering ribs in staggered relationship connected to said spars and interbraces.

3. In an aircraft structure upper and lower tapering spars in staggered relationship, diagonal interbraces having overlapping ends connected to said spars and upper and lower tapering ribs in staggered relationship connected to said spars and interbraces.

4. In an aircraft structure upper and lower tapering spars in staggered relationship, diagonal interbraces having overlapping ends riveted together, upper and lower tapering ribs in staggered relationship, a bolt adapted to fasten said ribs, interbraces and spars together at intersections.

5. In an aircraft structure upper and lower tapering spars in staggered relationship, diagonal interbraces having overlapping ends riveted together, bolts fastening said overlapped interbraces to said spars, and upper and lower tapering ribs in staggered relationship fastened to the heads of said bolts.

6. In an aircraft structure upper and lower spars in staggered relationship, said spars tapering gradually in. cross section, Z section diagonal interbraces having bent overlapping ends riveted together, a bolt adapted to fasten said overlapped ends to the spar, and tapering ribs in staggered relationship fastened to the heads of said bolts.

7. In a wing structure a spar of angular cross section, interbraces bearing against the sides of said spar and fastened thereto by means of a bolt, a transverse rib recessed to fit over said spar and said bolt head and fastened thereto.

8. In a wing structure a spar of angular cross section, interbraces bearing against the sides of said spar and fastened thereto by means of bolts, a lock washer bent to fit inner angle of said spar, a transverse rib recessed to fit over said spar and said bolt heads and fastened thereto.

9. An aircraft structure comprising spars, longitudinally diagonal interbraces with overlapped ends, transverse ribs recessed to fit over the spars and overlapped ends of said interbraces, means for fastening said overlapped ends to said spars and said means also connecting with said transverse ribs.

10. A wind-exposed surface for aircraft comprising a structure having spars tapering in design and thickness, braces holding said spars in staggered relation and a covering of sheet material having one edge secured to a spar member and another edge of a covering sheet overlapping said secured edge and fastened only to said sheet.

11. A wind-exposed surface comprising a structure having spars tapering in design and wall thickness, braces holding said spars in staggered relationship and a covering over said structure having overlapping edges, one edge being fastened to a spar and the other edge being fastened only to the covering.

12. A wind exposed surface for aircraft having an internal framing, and a covering of metal sheets, each sheet having one edge in interlocking engagement with the internal framing and the opposite edge secured to an adjacent covering sheet.

13. A wind exposed surface for aircraft comprising a structure having tapering spars in staggered relation, and a covering of metal sheets, each sheet having one edge in interlocking engagement with a spar, and the opposite edge secured to an adjacent overlapping sheet of the cover.

14. A wind exposed surface for aircraft comprising a structure having tapering spars in. staggered relation, and a sheet metal covering for the structure, each sheet having at its forward edge tabs engaging a spar and its trailing edge attached only to an adjacent overlapping sheet of the covering.

EDMUND B. CARNS.

Images