US1818971A - Airplane wing construction - Google Patents

Description

Aug. 18, 1931. J. v. cRlcHToN AIRPLANE WING CONSTRUCTION 4 Sheets-Sheet. l

Filed Nov. 19, 1929 gn muoz dames'rfabon, zy l j' dtor mm1 Aug. 18, 1931.

J. V. CRICHTON AIRPLANE WING CONSTRUCTION Filed Nov. 19, 1929 4 Sheets-Sheet4 2 Aug. 18, 1931. J. v. cRlcHToN AIRPLANE WING CONSTRUCTION Filed Nov. 19, 1929 4 Sheets-Shee4 5 dftoz um,

Aug. 18, 1931. J. v. cRlcHToN AIRPLANE WING CONSTRUCTION Filed NOV. 19, 1929 4 Sheets-Sheet. 4

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d No: 1 m q properly Patented Aug. 18, 1931 UNITED STATES PATENT OFFICE JAMES V. CRICHTON, OF PHILADELPHIA, PENNSYLVANIA, ASSIGNOR OF ONE-HALF T0 KARL SALBERG, 0F PHILADELPHIA, PENNSYLVANIA AIRPLAN E WING CONSTRUCTION Application iled November 1.9, 1929. Seriall No. 408,213. i

The object of the invention is to provide improvements in airplane construction and more especially in the construction of their Wings.

With the rapid increase in demand and the standardization of airplanes, there has developed as in the case of the automobile a demand for decrease in cost of production, Without sacrificing in the slightest the necessary degree ofJ rigidity. That is, while the all-important Wings must to all-intents and purposes be sufliciently elastic to prevent the equivalent of brittleness, they must in the general acceptance of the term be rigid both longitudinally and transversely, with a high coefficient of safety, to permit the temporary accommodation of excess loads as when abnormally strained by suddenly varying air or Wind pressures.

An object of the invention therefore is to provide a construction which will insure the maintenance of the proper degree of rigidity, particularly in a longitudinal direction between Wing tips, and at the same time produce the proportionately necessary transverse anti-iiexing strength. j

Another object then is to reduce such Wing construction to a system of lfabrication comparable with high speed and low cost construction in other lines vof standardized articles, such construction consisting primarily in longitudinal girders, connected by positioned transverse bracing and such surface members as will provide a relatively unbroken foundation for fabric or other covering, or Which can be employed Without covering in the first instance, or in` sure continued functioning of the Wings if and when such covering may be removed or destroyed.

','With these and other objects in mind the present invention comprises further details of construction and operation which will be fully brought out in the following description when read in conjunction with the accompanying drawings in which Fig. 1 is a schematic view representing the front elevation of a monoplane in which the oppositely lextending wings are integrally connected to and are in alignment with each other upon the opposite sides of any desired form of fuselage; Fig. 2 is a top plan view of the same, indicating the arrangement of the longitudinal girders; Fig. 3 is an enlarged transverse sectio on the line 3-3 of Fig. 2; Fig. 4 is'an enlarged fragmentary plan view of a portion of the Wing surface elements; Fig. 5

is a transverse section of the same on the line 55 of Fig. 4; Fig. 6 is an elevational view" of one of the longitudinal girders shown in Fig. 3 and substantially as though al section were taken on the line 6-6 of Fig. 3'; Fig. 7 is a similar view of one of the diagonally bracing members shownin Fig. 3 and substantially as thoughV taken on the line 7-7 of Fig. 3; Fig. 8 is an enlarged transverse section on the lines 8-8 of Figs. 6 and 7; Fig. 9 is an enlarged vertical fragmentary section similar to the forward or left-hand portion of Fig. 3, but showing a modified form of assembly; Fig.`10 is a top plan view of a fragmentary portion of one of the corrugated surface elementspshown in F-ig. 9;

Referrmg to Figs. 1 to 8,inclusive, the

improved Wmg structure is characterized by the fact that the girders of Fig. 6 and the diagonal braces Yof Fig. 7 extend longitudinally from tip to tip of the oppositely directed wings 1 and 2, that is, transversely of -the normal line of motion of the airplane body or fuselage 3. Referring' specifically to-Fig. 3, the cross .section of the wing illustrates the latter as being formed of any desired number of longitudinally extending substantially vertical girders 4, represented in plan in Fig. 6. Each of these girders is t0 be stamped and otherwise formed by dies from a single blank of sheet metal and essentially comprises in the present instance an upper preferably straight edge portion 5 and a lower edge portion 6, which from a maximum girder width at the center or junction of the two wings it converges towards the oppositeends into substantially pointed. terminal portions 7. This girder has removed from its body portion excess material to form substantially triangular openings 8, so arranged as to provide between the diagonally extending guy sections 9, which zig-zag from upper to lower and lower to upper edge portions from one end to the other of the girder.

In order to transversely strengthen each of the respective upper and lower edge portions 5 and 6 and the guys 9, each of these portions of the girder is preferably corrugated substantially as shown in Fig. 8 to form a central concavo-convex section 10, disposed be tween laterally deflected edge portions 11, all cooperating and tending to produce local rigidity of the various sections o'f the girder, in order to provide and maintain a predetermined uniform rigidity of the girder as a whole.

Referring again to Fig. 3, it will be noted that there extends from the lower` edge portion of certain laterally positioned girders to the upper edge portion of intervening girders diagonal braces 12, which from Fig. 7 are seen to comprise in themselves a construction similar to the `girders before described. Each o'f these braces comprises a relatively straight edge portion 13 and oppositely positioned slightly diagonally extending edge portions 14, said edge portions at their longitudinally opposite ends being connected by transversely opposite end portions 15, while between said end portions the transversely opposite edge portions are integrally formed by means of diagonally extending guy sections 16 formed between substantially triangular cutout portions 17.. Each of these edge, end, and guy sections is also corrugated and provided with laterally directed edge portions, as shown in Fig. 8 and previously described.

Also, it will be noted that the opposite edge portions 5 and 6 of the girders of Fig. 6 and the corresponding edge portions 13 `and 14 of Fig. 7 are provided with spaced apertures which are adapted to receive rivets 18, as shown in Fig. 3. It willalso be realized that while the central portion of the braces 12 are diagonally positioned as shown in Fig. 3, they are warped or flexed as Vthey proceed towards their opposite end portions 15, since said end portions connectadjacentV girders at the opposite ends 19 of the wing structure, as shown in Fig. 2, said ends lying substantially in a horizontal plane and ing of relatively shallow height, as indicated at the laterally opposite ends of Figs.`1 and 6. It

`ing diagonally extending should also be noted in passing that the act of flexing these brace members adds to them an increased rigidity and strength .which they would not otherwise have were they to extend in the same general direction from end to end.

After the girders 4 and brace 12 areassembled as shown in Fig. 3, the gaps between them are inclosed by means of sheets 20 of relatively thin metal, each .sheet as indicated in Figs. 4 and 5 being characterized by a central laterally corrugated portion 2l, bounded forwardly and rearwardly by transversely corrugated marginal portions 22, which merge into outwardly directed sub stantiallyv parallel flanges 23. These flanges are duly perforated and also receive the permanent rivets 18, as illustrated in Fig. 3.

The forward portion of the wings may be inclosed by means of a centrally cors rugated transversely curved section of met` al 24, the opposite marginal portions 25 of which are longitudinally corrugated and terminate in preferably aligned flanges 26, which are secured to the opposite upper and lower edge portions of the foremost girder. portion means of either two converging plates 27 and 28 or by means of a single plate folded centrally at 29 to form a relatively pronounced trailing edge. This plate or plates may also be corrugated at 30 to afford transverse stiness, while their divergent marginal portions are corrugated at 31 and provided with preferably aligned flanges 32 for securing to the respective upper and lower edge portions of the rearmost of said girders 4.

Referring to Figs. 9, 10, and 11, a modification of the structure hereinbefore described is illustrated as comprising substantially vertical girders 33 which may be similar to the girders 4 illustrated in Fig. 6. The upper portions of adjacent girders in this form of the device are connected together by brace members of substantial V cross section, havsides 34, which at their margins merge into nection with the adjacent edge portions of said girders,

perforated and adapted to be secured by rivets 37, welded, or the like, to a similar portion of a similar brace which resembles an inverted V. Thus when completely assembled a substantially X form of bracing is provided which for some purposes has been found to offer most desirable results.

ianges 35, for con-` and provided with a central' preferably plane portion 36 which is duly On the other hand, the trailing edge of the wing structure is formed byl The spacesl between the opposite ends of each Y of said brace members 34 are spanned and closed by sheets of relatively thin metal 38, the central portions of which lie in either curved or straight planes which includesor are tangential to the outermost free edge portions of the girders 33 and intervening braces to the lower edge girder 45, if the 34. EachA of these sheets 38 is corrugated along its opposite marginal portions at 39 and thenceoutwardly directedY in substantially parallel flanges 40, which in turn are perforated and secured by means of rivets to similar flanges upon adjacent sheets and to said adjacent edge portions of girders and braces.

Instead of corrugating the central areas of each of said sheets 38, there may be secured to said areas by rivets, spot-welding, or the like, duly corrugated or folded and flanged stieningmembers 41, substantially ,as shown in Figs. 10 to 12 inclusive. Thus, these plates are transversely stiffened so as not to belly, collapse or appreciably vibrate under varying wind ressures, and the arrangement of said stiffemng members may be according to any desired geometric or other design according to the taste or preference of the designing engineer. The forward surfaces of the opposite upper and lower edge portions of the foremost girder 33 are connected by` what might be termed half braces 42, which are connected to ether by means of parallel flanges 43, well orward of the central portion ofthe adjacent girder. The line o f connection of these half braces is then connected to the opposite edge portions of said foremost girder and to the opposite edge portions of the respective brace members b means of suitable shaped metal sheets 44, w ich may be formed and stiHened in a manner similar to the sheets 38 hereinbefore described.

In Fig. 13, vertical girders 45 are shown as being provided with rearwardly directed marginal flanges 46, it being understood that the lower portion of the wmg is a duplicate of the upper portion illustrated. The under side of each of said flanges is connected to the flange 47 of a downwardly and rearwardly extending brace member 48. Thereafter proceeding preferably from the rear or trailing edge of the plane, a surface sheet of metal 49 is laid upon the combined flanges 46 vand 47 and forwardly thereof is bent downwardly to form a diagonal brace member 50, which terminates in .an angularly directed flange 51, adapted to abut against and be secured to the central portion of the brace member 48 and to the adjacent flange 51 of a rearwardly and upwardlyextending brace member 50', the lower edge portion 52 of whichA may be bent forwardly and secured portion 53 of the adjacent lower portion of the wing structure is other than a substantial duplicate of its upper portion. It will also be noticed that the rear edge portion of each of the plates 49 lies upon and is vduly secured to the combined flanges 46 and 47 and to the for.- ward portion of the next plate 49 rearwardly thereof, where it joins its forwardly extending brace section 50, as clearly illustrated in said Fig. 13.

Referring now to Fig. 14, upper and lower surface plates 54 and 55 are used, these plates being connected to adjacent plates by welded or riveted flanfges 56. Substantially the central portion o the oppositely positioned plates 54 and 55 are connected together by vertically extending girders 57,

which may be similar in construction to thel girders 4, 33, and 45 illustrated in Fig. 6. In order to insure rigidity of this modified construction, substantially V-shaped brace members 58 are used, similar to the braces 34 in Fig. 9, but manner that their central portions 59 may be connected together upon the opposite sides of and to the intervening girder 57. The laterally opposite marginal portion 60 of these brace members may be secured in any suitable manner and at any suitable position to the opposed plates 54 and 55, according to the preference of the designer.

Fig. 15 illustrates another way in which the surface plates, girders and braces may be joined so as to provide and insure the maintenance of a substantially unbroken outer wing surface. .This joint is illustrated in Fig. 15 for use in such structures as those shown in Figs. 3 and 8, though it may also be adapted for use with other methods of assembly. Primarily, we have lthe upper portion of a girder 61, upon the opposite sides of which are the upper portions 62 of diagonally extending brace members 63. Secured in turn to the opposite sides of said marginal portions 62 of said brace members are the outwardly directed flanges 64 of the longitudinally corrugatedmarginal portions 65 of surface plates 66 of sheet metal. and of any desired formation. However, it will be noted that in cutting and forming each of said surface plates, a longitudinally extending deression or shoulder 67 is provided at the junction between the central portion of the plate with the marginal portion 65 and that the marginal portions 62 of the brace mem.

ber 63 are extended outwardly and curved in turned upon their sides,"in such A opposite direction in order that their edge portions 68 lie within these depressions 67 and cover the spaces within the marginal plate corrugations 65, thereby providing a substantially smooth and unbroken wing surface as is clearly illustrated.

In conclusion it should be noted that several embodiments of the invention have been described in order to indicate something of the breadth of the invention as conceived and perfectedyby the applicant, and that while one for-m may be more ellicient than another under certain conditions, each form has its advantages and is ada ted for use under certain characteristiccon 'tions and with certain types of airplanes.

Referring to Figs. 16 to 19 inclusive, there is shown a construction which provides for they use of sectional longitudinal girde'rs 1n divergent arms 77,

order to meet condition-s'which arise when the overall tip to tip wing length is so great that it is difficult to handle single girders Without their tending to become bent out of shape or warped during the process of assembly. Otherwise, the resulting structure, after the assembly of the several. sections is complete, is the same. 'In this modification of the device, a series of girder sections 69 is provided as best shown in Fig. 16, each section comprising preferably slightly tapering oppositely positioned upper and lower marginal portions 70 and 71, connected at their opposite ends by end sections 72 and 73, obviously of different length, while said first sections are preferably connected together by means of a transversely extending rib 74 and by oppositely directed diagonally extending ribs 75, in order to provide an adequately braced structure both longitudinally, transversely and diagonally. Each of said longitudinal, end and rib sections of the girder is preferably provide with suitable corrgations 76, in order to further stiffen the cross section of each of said marginal rib sections independently of one another, and substantially as indicated in Fig. 8 above described.

Referring to Fig. 18, it will be noted that adjacent girder sections 69 may be connected and braced with respect to eachother in any suitable manner, but for purpose of illustration they are braced substantially as hereinbefore -described and shown in Fig. 9. By this method pairs of substantially V-shaped braces are provided, each brace comprising connected together by normally adjacent flattened riveted or bolted sections 78, while the outer free end portions of these brace arms are bent at 79 into parallelism and duly riveted or otherwise secured together upon the opposite sides of and to the upper and lower marginal portions 70 of the several sectionswhich are united to form unit girders.

Finally, the lends of these adjacent parallel brace portions of neighboring braces terf minate in oppositely extending aligned flanges 80, to which may be directly secured surface plates or preferably metallic sheets 81. Thereafter, in order totransversely Vconnect in rigid relationship the adjacent'edge lportions of each wing section thus formed,

there are provided pairs of angle irons (shown specifically in Fig. 19), comprising normally aligned fianges 82, which duly rest against the outer surface of the cover plates 81 and are secured both to said plates and to the brace fianges 80 therebeneath, as shown in Figs. 16, 17 and 18, while said braces also comprise parallel flanges 83, which are adapted to be secured together upon the opposite sides of upwardly extending parallel marginal portions of said cover plates 81, angularly deflected intoA parallelism, as

gent portions connected at shown in Figs. 16 and 17. The flanges of each of said angle irons respectively are connected together by preferably parallel webs 84, which from Fig. 9 are employed to increase the rigidity of said braces.

This construction of wing girder in particular and wing in general obviously makes for easier assembling, while in such a structure it is obviously more easy than usual to replace defective or damaged sections, whether the sections are girder sections, cover plate sections, or otherwise, while the cost of production is not materially greater than forms hereinbefore described, and in other ways the structure offers highly desirable commercial advantages towards the end of quantity production of highly standardized nature.

' Having thus described my invention, what I claim and desire to protect by Letters Patent of the United States is 1. An airplane wing,oomprising spaced longitudinally extending girders, diagonally extending braces, and surface plates connecting the marginal portions of said girders, each of said girders being provided with cutout regions forming between them diagonally extending brace portions, the said cutout regions progressing in staggered relation between marginal edge portions, said braces being corrugated to increase their rigidity.

2. An airplane wing, comprising spaced longitudinally extending girders, diagonally extending braces, and surface plates connecting the marginal portions of said girders, each of said girders being provided with cutout regions forming between them diagonally, extending brace portions, the said cutout regions progressing in staggered relation between marginal edge portions, said brace and marginal portions being corrugated to provide increased rigidity.

An airplane wing, comprising transversely spaced longitudinally extending girdilo ers, and intermediate brace Vgirders of ancomprising diver-` their free edge portions to corresponding edge portions of said first girders.

4. An airplane wing, comprising transversely spaced longitudinally extending girders, and pairs of intermediate brace girdgular transverse section ers of V-shaped cross section connected together at their centers and at their free edge portions being connected to the-edge portions of said first girders.

5. An airplane wing, comprising transversely spaced` longitudinally extending girders, pairs of intermediate brace girders of V-shaped cross section connected together at their centers and at their free edge portions being connected to the edoe portions of said first girders, and ribbed plates connectlao ing said girders and inclosing the space therebetween.

6. An airplane wing, comprising transversely spaced longitudinally extending girders, pairs of intermediate brace girders of V-shaped cross section connected together at their centers and at their free edge por-` tions being connected to the edge portions of said irst girders, and corrugated plates secured to, and said plates inclosing the space between said girders.

7. An airplane wing, comprising transversely spaced longitudinally extending girders, means to transversely brace said girders with respect to one another, and plates connecting said girders and inclosing the space therebetween, said plates being provided with transverse corrugations to stillen them, and with marginal longitudinal corrugations merging into flanges normally connected to the marginal portions of said girders.

8. An airplane wing, comprising longitudinally extending sectional skeleton girders, each section comprising oppositely disposed marginal portions and connecting end portions, means to rigidly secure adjacent girders fixed with respect to each other in slightly spaced relation, and means to brace the opposite marginal portions of said sections with respect to each other.

9. An airplane wing, comprising longitudinally extending sectional skeleton girders, each section comprising oppositely disposed marginal portions and connecting end portions, means to rigidly secure adjacent girders fixed with respect to each other in slightly spaced relation, and integral transversely extending braces connecting the opposite marginal portions'of said sections with respect to each other.

10. An airplane wing,comprising longitudinally extending sectional girders, each section comprising oppositely disposed margmal portions and connecting end portions, and means to rigidly secure adjacent girders together in slightly spaced relation, said girders being provided with cutout regions separated by transversely extending longitudinally corrugated' braces integrally connected to said marginal portions.

11. A sectional airplane wing, compris.- ing longitudinally extending girders in each wing section, diagonally eX- tending braces connecting` the corresponding girders in each wing section, cover plates eX- tending between said girder sections and inclosing the normal upper and lower sides of the space within each wing section, and means connecting adjacent edge portions of said plates and rigidly securing said sections together in slightly spaced relation.

12. A sectional airplane wing, comprising longitudinal girders in each section, braces connecting the girders of each section, cover plates extending between and inclosing the normal upper and lower sides of the` space within each wing section, and means connecting adjacent edge portions of said plates and rigidly securing said sections together.

13. A sectional airplane wing, comprising longitudinal girders in each section, braces connecting the girders of each section, cover platesextending between and inclosing the normal upper and lower sides of the space within each wing section, the marginal portions of said plates at the ends of each section being bent to form flanges, and angle-irons connecting adjacent plate flanges together, and respectively secured to the body portions of said plates and to said respective girder sections.

In testimony whereof I have aliixed my signature.

.JAMES V. CRICHTON.

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