US2733026A

US2733026A - Aircraft ski

Info

Publication number: US2733026A
Authority: US
Publication date: 1956-01-31
Anticipated expiration: 1973-01-31

Description

F. J. DITTER AIRCRAFT SKI Jan. 31, 1956 5 Sheets-Sheet 1 Filed May 17, 1952 INVENTOI? FRANCIS J. DITTER 7 9 BY ummy" F. J. DITTER I AIRCRAFT SKI Jan. 31, 1956 5 Sheets-Sheet 2 Filed May 17, 1952 INVENTOR III L I I I I FRANCIS J. DITTER BY M4, am Jan. 31, 1956 F. J. DITTER 2,733,026

AIRCRAFT SKI Filed May 1'7, 1952 5 Sheets-Sheet 3 FIG. 3

nvvewron FRANCIS J. DITTER a! g Arron" Jan. 31, 1956 F. J. DITTER 2,733,026

AIRCRAFT SKI Filed May 17, 1952 5 Sheets-Sheet 4 FIG.4

FIG.5

INVENTOR FRANCIS J. DITTER I BY w Jan. 31, 1956 F. J. DITTER 2,733,026

AIRCRAFT sx:

Filed May 17, 1952 5 Shae as-Sheet 5 O Q LL. g l mug-127 i llll'll|iiiiil r'' .1: I I l 1 g In INVENTOR FRANCIS J. DITTER B) W m anrmnun United States Patent" fiiice The present invention relates. to. a novel aircraft ski adapted to be employed in combination with the conventional wheel.- landing gear of an aircraft. The ski is adapted to be actuated from the condition in which the wheel is in landing position to the condition in which the ski is, in landing position. In addition, the. inven-. tion contemplates the. use of the landing wheel on top of the. ski such that thecompression of the tire on landing assists in the shock absorbing function.

It is therefore an object of the present invention to provide novel aircraft skis adapted to be employed. in conjunction with conventional aircraft. wheel landing gear.

The following description of the invention will be with particular reference to the drawings in which Figure 1 is a perspective .view of the. forward portion of the'aircraft equipped, with the skis of the. presentinvention;

Fig. 2 is a sideelevation ofthe ski of'Figurel showing the ski mounted'on the aircraft, the. latter being indicated in dotted lines;

Fig. 3 is a cross sectionalview of the ski taken through the mounting pedestallocated intermediate the ends of the ski;

Fig. 4 is a fragmentary side. elevation partly in section showing the ski in landing position, the solid linesindicating the position of the parts at the moment of actual landing, the dotted lines indicating the position of the parts during flight;

Fig. 5 is a. plan view of 'a the mounting pedestal;

Fig. 6 is a perspective showing detailsof the mounting and actuating mechanism;

Fig. 7 is a side elevation showing the wheel in landing position;

' Fig. 8 is a fragmentary cross section. of the ski. illustrating the position of the wheel. when the ski is retracted;

Fig. 9 is, a fragmentary cross. section. indicating. the

pos tion of the wheel withthe. ski in landing position portion of Fig. 4. showing and the compression of the tire onthe ski at the pointof landing; and

Fig. 10 is a fragmentary cross section showing position of the wheel. with-the ski in landing position, under flight conditions; and

Fig. 11 is a'fragmentary cross section showing a modification of the actuating arrangement.

With particular reference to. Figure l; the ski is composed of a base shoe generally indicated at 11', which is curved both longitudinally and transversely. The forward or toe portion of the base shoe 12 is curved, upwardlyas is the rear or heel portion 13. The base. shoe has a lateral portion 14 extending along the approximate forward half of the ski. There is provided, a flange 15 which is curved upwardly along the outside edge of the lateral portion 14, andalong the inside edge of the ski as shown inFig. 3..

Superimposedon the baseshoe is a' channel member 16 Eatented Jan. 31, 1956 which has a generally inverted \I -Sha e-in cross section. Thischannel may be formed by rolling a piece of sheet stock. Accordingly the base. 17 of the: V isav straight line longitudinally andis curved in cross-section. A flangeis provided. at the. outward edges of the V for. suitable-fess tening such as riveting to thebase shoe. The ski may. be provided with transverse reinforcing diaphragmslocated inside of thechannel and being secured theretoand to the. base shoe. In the forward portion of the ski these reinforcingdiaphragms 18 extend from the outside of. the channel out over the; lateral: portion 14 of the. ski to. serve asadditional; support therefor. This; portion of the skiis provided with. a suitable cover 19.

The ski is. attached tosthelanding gear by the. follow ing means. At the: intermediate portion of the ski the channel. ldis cutout and a saddle 20*is provided.- This saddle is shaped. to the general contour of the channel 16-but likewise has its central portion. cut out At the. sides of the saddle there are provided a. pair of pedestal members 22 which may be seen in Figs. 2, 4 and 5; These pedestal members are. composed. of sheet members. suit-.- ably. attached to the saddle 20' by means of .flanges or legs 23 which extend downwardly along the saddle 2i) and are, Welded thereto. These. pedestal. members are provided with openings near. the top thereof for insertion of a boltor. pin24.

The actuating mechanism can best be seen withreference toFigs, 3 and 6. A tube:30;providedwitha bronze bushing 31 has attached to it a hydrauliccrank arm 32 and a skicrank .arm:33.- These are. suitably attached to the tube 30, for example by welding. The. hydraulic crank arm. is. illustrated as a pair of arms; .while-the skicrank arm is. illustrated in Fig. 6v as, a built-up enclosed structure. At the. upper portion of the ski crank arm there is provided atransversestube-34: likewise provided with. a. bronze bushing 35. They tube 34 and the bushing 35. are adapted to. he slipped ontov a stub shaft 36 which is suitably attached at the end not shown to the inside. oithe, regular landing wheel shaft. A pair: of

bearing washers, 37 and. 38 are employedand the bushing;

'sitepedestal member, and is held by. meansof nut, 41..

Suitable bearing washers. 42 and 43 are provided to. per.- mit the, entire ski assembly to rotate aboutthe pin.24.

' In Fig. 6 there is illustrated a bridging support member generally indicated at 45. This bridging'rnember is composed of .a central. web. id-and.

lateral flanges

47 and 48; The bridging support lower central portion so that it may be placed in position over tube 3.0 after tube 3.0 hasbeen. attached to the; pedestal supports. This bridging. member may then be. bolted'down to the topv of pedestal member 20. The purpose of. this bridging member at the point at which the central portion of the ski has been cut out. By thus cutting out the'central portion of the ski and providing. this bridging support member,.

member is cut out in the;

is essentially to add strength;

illustrated the actuating mechanism 3 for this hydraulic cylinder. tached at its outer end to the hydraulic crank arms 32 by means of bolt 52. The piston arm is provided with an elongated slot 53 at its outer end through which the bolt 52 passes. The elongated slot permits the tire to be used as part of the shock absorbing mechanism. At the same time this use of the tire to absorb shock has been accomplished without placing any load on the hydraulic cylinder or the hydraulic system. In Fig. 4 in the dotted lines will be seen the position of the wheel during flight but when the ski has been lowered for landing. Under these conditions the wheel bears lightly on the top of the lateral surface 14. It will be seen in the dotted lines of Fig. 4 that the pin 52 is near the inner end of the slot 53. In the solid lines in Fig. 4 will be seen the position of the tire at the point of impact with the landing surface. The tire is compressed to assume part of the load. As a result of this compression the ski crank arm 33 has rotated counterclockwise from the dotted line position to the solid line position. The pin 52 has likewise moved from the dotted line position to the solid line position, as has the piston rod 51. The slot 53 has permitted this movement without any longitudinal movement of the piston rod 51. Thus no change has been made in the load on the hydraulic system by the impact of landing.

In Figs. 7 and 8 is seen the relative position of the parts when the landing wheel is in operative position. In Fig. 9 will be seen the position of the parts at the point of landing on the ski. Fig. 10 shows the relative position of the parts during flight when the ski is in landing position.

In Fig. 2 is illustrated the means for regulating the ski by means of cables so that it will assume a suitable attitude during flight. For this purpose there is provided near the forward end of the ski heavy elastic cables 60. These tend to keep the nose of the ski elevated against the pull of the rear limit cable 61, which is a heavy steel cable, the purpose of which is to keep the nose of the ski from being pulled up into contact with the airplane or into the path of the propeller. The steel cable 62 provided ahead of the wheel is a limit cable which is normally slack, but which will keep the nose of the ski from falling in the event that the elastic shock cable 60 is not able to maintain it in normal flight level. At the rear of the ski is provided an auxiliary steel limiting cable 63 which likewise serves to keep the nose of the ski from rising too high.

When the plane is taxiing on the ski the compression of the tire provides a small amount of slack in the limit cables to provide a reasonable amount of pitching of the ski caused by unevenness of the landing surface. During flight, however, the tire again expands and the ski is held in proper attitude by the combination of the shock cord and the limit cables.

In Fig. 11 there is illustrated a modification of the invention in which there is provided a single crank arm and the actuating means is attached to this crank arm. The ski crank arm 33 has a hole passing therethrough in which bolt 60 is supported in the following manner. A spacer sleeve 61 of greater length than the thickness of rod 51 is placed on bolt 60. This bolt is then passed through slot 53, washer 62 placed thereon, and the bolt then passed through the hole in crank arm 33. A washer 63 and nut 64 hold the assembly together without frictional engagement along the sides of rod 51. This modification may necessitate some lateral adjustment of the mounting for the hydraulic cylinder as well as some centering of the ski crank arm on the tube 30. This modification provides a simpler and less expensive structure for some installations. Other modifications may be made without departing from the spirit of the invention. For example, the slot 53 may be placed in the lever arm for actuating the ski rather than in the rod 51. Likewise, mechanical stops may be provided to limit the movement The piston rod 51 is at- 4 of the ski crank without the application of any additional load on the hydraulic system.

It will thus be seen that there has been provided a novel ski structure which may be mounted on the conventional aircraft landing gear, such that both the ski and the wheel may be in position at the same time. In addition, the ski is actuatable from the wheel landing gear to the ski landing gear. This may be performed during flight by means of controls located in the cabin. The ski is likewise provided with a lateral extension to the ski surface which serves to increase the landing area and to provide a bearing surface for the wheel such that the compression of the tire may be relied on for part of the shock absorbing structure. The actuating system is provided with a means which permits this compression without any load on the hydraulic system. Furthermore, the ski is mounted inside of the wheel such that the ski is almost directly beneath the landing gear structure instead of being laterally outwardly a considerable distance if the ski were placed outside the wheel.

I claim as my invention:

1. An aircraft landing ski adapted to be mounted on the wheel shaft of an airplane comprising a single elongated landing surface, and a lateral landing surface extending outward along the forward portion thereof, means for attaching said ski to the wheel shaft of an airplane at the inner end of said wheel shaft such that the elongated landing surface is inside of the wheel and the lateral portion of said landing surface is in line with said wheel, a lever arm mounted on the ski and on the inner end of said wheel shaft, a second lever arm operable with said first lever arm, means for operating said second lever arm including a rod having an elongated slot therein and being attached to said second lever arm by means of a pin passing through said slot.

2. An aircraft ski comprising a single elongated landing surface and a lateral landing surface extending outwardly along the forward end of said ski, and means for mounting said ski on an airplane such that the elongated landing surface is to one side of the wheel and the lateral surface is in line therewith, means associated with said means for mounting, for actuating said ski so that the landing wheel is lowermost in one position of said actuating means and so the ski is lowermost in another position of said actuating means with the wheel positioned on top of and in contact with said lateral surface.

3. An aircraft ski comprising an elongated landing surface, an inverted channel member overlying said elongated surface and secured thereto, a saddle overlying said inverted channel, said channel and said saddle being cut out near the middle thereof, support means carried by said saddle for pivotally mounting said ski on a landing gear, said pivotal mounting being disposed below the base'of said inverted channel and a longitudinal removable bridging support member extending over said pivotal mounting from a forward portion of the saddle to a rearward portion of said saddle.

References Cited in the file of this patent UNITED STATES PATENTS 401,429 Granger Apr. 16, 1889 1,757,687 Silva May 6, 1930 1,844,295 Perry Feb. 9, 1932 2,106,934 Saulnier Feb. 1, 1938 2,261,751 Brintnell Nov. 4, 1941 2,492,965 Carr Jan. 3, 1950 2,532,610 Ditter Dec. 5, 1950 2,532,611 Ditter Dec. 5,, 1950 2.539.817 Ditter Jan. 30, 1951 FOREIGN PATENTS 67,769 Germany Apr. 5, 1893 71,226 Sweden Feb. 24, 1931 181,436 Germany Feb. 16, 1907