US2014876A

US2014876A - Aircraft provided with a gun

Info

Publication number: US2014876A
Application number: US744821A
Authority: US
Inventors: Birkigt Marc
Original assignee: Individual
Current assignee: Individual
Priority date: 1934-03-01
Filing date: 1934-09-20
Publication date: 1935-09-17
Anticipated expiration: 1952-09-17

Description

Sept. 17, 1935. M. BIRKIGT AIRCRAFT PROVIDED WITH A'GUN Filed Sept. 20. 1934 Patented Sept. 1,7, 1935 2,014,876 AIRCRAFT PRovmEn yWIII'II A GUN Marc Birkin, Bois-Colembes, France Application 6 Claims.

The present invention relates to aircraft provided with a gun adapted to shoot in the direction of the axis of revolution of a propeller.

The object of the present invention is to attenuate the effect of recoil of guns so fitted on an aircraft.

The essential characteristic of the present invention consists in providing guns mounted in this manner on an aircraft with a muzzle recoil apparatus which is disposed in front of the propeller (with reference yto the direction in which the gun is to shoot).

Other characteristics of the present invention will result from the following detailed description of an embodiment thereof. v

A preferred embodiment of the present invention will be hereinafter described, with reference to the accompanying drawing, given merely by Way of example, and in which:

The only figure is a vertical sectional view, on a line passing through the axis of revolution of the propeller, of the front 'part of the fuselage of an airplane fitted with a gun in the manner above referred to, according to the present invention.

In the specific embodiment which will be hereinafter described, it has been supposed that the airplane is provided with a single engine driving the propeller through which the gun is to shoot.

As far as this airplane is concerned, the general arrangement. with the exception, of course, of the gun itself, may be of any conventional or other kind. For instance, it includes, at the front part of the fuselage I an engine 2 adapted to drive, through a suitable reducing gear 3, a tubular shaft Il, which is not in line with the axis of the crankshaft of the engine and to ywhich is secured a propeller 5.

Concerning now the gun, it can be fixed in any suitable manner, known in itself, to the casing of the engine, for instance by providing at the front end of tube 6 of said gun a groove 1 capable of being fitted, after mounting of the parts, in a corresponding hole provided in the casing of the engine. In any case, the parts are assemb'led in such manner that the gun canshoot through tubular shaft 4. Finally, tube 6 is prolonged, toward the front, beyond the hub of propeller 5 for instance by fixing thereto a tube 8 -acting as a `protection against the flames escaping from the `muzzle of the gun.

It should be well understood that the whole arrangement above described is already known per se.

According to the present invention, this arrangement is completed by providing the gun 6 september 2o, 1934, serial No. 744,821 In France March 1, 193.4

with a muzzle recoil sysetm which is located in front of the propeller 5.

Advantageously, this recoil device is xed either to the extremity of tube 6 if the latter extends suliiciently far in a forward direction, or to the 5 tube 8 above referred to.

The recoil device illustrated in the drawing consists essentially of a wall 9 which is located opposite the orifice of tube 6 or of the tube 8 attached to said tube 6 (for instance ata distance l0 from said orifice equal to four times the caliber of said projectile). This structure 9 is provided with a hole I0 locatedin such'manner that the projectiles issuing from said tube can pass through said hole. 'Ihis hole Ill is made of such 'l5 a diameter that when a projectile Il is passing therethrough this hole I0 is fully stopped by said projectile.

Thus, when a projectile is passing through this hole Ill, the burnt powder gases issuing from the 20 muzzle of the gun cannot escape through said hole and therefore strike wall 9, thus producing a thrust directed toward the front and which balances, to a certain degree, the rearwardly directed thrust that is produced by the recoil of the 25 gun.

Of course, according -to the present invention,

the muzzle recoil device may be given any suitable shape whatever.

However I have found that the specific arrange- 30 ment illustrated by the drawing is -particularly advantageous for practical purposes.

According to this arrangement, the central portion of wall 9 is given the shape of a body of revolution such that the edge of hole Ill is sub- 35 stantially tangential to the trajectory of the projectiles, this wall 9 then curving progressively, in the shape of a portion of a tore (as shown in the drawing), its periphery being directed toward the rear of the. airplane. Consequently, with such an arrangement. wall 9 constitutes a kind of 'deflector, in the shape of a body of revolution, which causes the gases issuing from thev muzzle of the gun=to finally escape towardsthe rear, without producing any shock. The reaction of these gases upon'wall 9, while they are being deflected produces the forward thrust exerted on said wall 9, as above explained.

In order to better guide the burnt gases, a sec- 50 ond wall I2 is provided. This second wall can be fixed directly to the end of tube 6 'or tube 8 as the case may be. It is located on the inside of the kind of cap formed by the wall 9 above referrel to, and vat a suitable distance from said 55 tangent atthe front and two .branches extending- Athe rear edge of walls 9 and wall 9 for permitting a satisfactory flow ofthe gases.

With this arrangement, wall 9 can be fixed in the desired position, at the desired distance from the muzzle of the gun, by means of ribs I3, for instance radially disposed, which connect said wall 9 to wall l2. As above stated, this wall l2 is directly fixed to the muzzle of the gun.

Although wall 9 may be given any desired external shape, I have found that it is particularly advantageous to give it approximately the shape of a cone, thusforming, at the front end of the fuselage a streamline structure.

Ithen fix to propeller 5 a ring Il in the shape of a frustum of a cone, arranged to revolve together with the propeller and such that its rear edge is located opposite the front edge of the fuselage while its front edge is located .close to The whole of the external wall of the defleotor 9-I2 above described, of the revolving ring I4 fixed to the propeller, and of the front part of the fuselage can thus be given a substantially ovoid shape as best suited to a good penetration into air.

However, preferably, I give the rear edge of wall 9 a diameter slightly larger than that of the front edge of ring-shaped element I4, in order to leave between these two elements an annular passage of a width equal to some centimeters, through which the burnt powder gases can escape toward the rear.

'Ihe arrangement above described is particularly simple and it permits of combining the advantages of a muzzle recoil device for checking the recoil of the gun with4 those of a streamline structure as perfect as possible of the front portion of the fuselage of the aircraft.

While I have described, what I deem to be practical and efficient embodiments of the present invention, it should be well understood that I do not Wish to be limited thereto as there might be changes made in the arrangement, disposition and form of the parts without departing from the principle of the present invention as comprehended within the scope of the appended claims.

What I claim is:

1. In an aircraft including a fuselage, a propeller provided with a hollow hub and a hollow shaft for driving said propeller, the combination of a gun adapted to shoot through said hub along the axis of said shaft in a frontward direction, a deilector located in front of said propeller, the

^ internal wall of said deector having the shape of la surface of revolution about said axis the generatrix of which is a curve having a vertical both in a rearward direction, one of said branches being tangent at its end to the path 'of travel of the projectiles issuing from said gun other branch extending outwardly to a greater distance toward the rear, and a ring-shaped wall mounted about the axis of said propeller so that its rear edge is in line with said fuselage and its front end is of a diameter slightly smaller than that of the rear edge of the outer wall of said deector. I

2.4111 an aircraft including a propeller having a hollow hub and a hollow shaft for driving said propeller, the combinationof a gun adapted to shoot along the axis of the 'shaft of said propeller in a forward direction, with a combined recoil ,and the Apowder gases to direct compensating device and air resistance reducer comprising a substantially conical member located in front of the propeller with its apex forwardly, said member having a hole therein for the passage of a projectile, the size of said member being vsuch that its outer surface directs the air in a streamline with the outer surfaces of that portion of the aircraft directly to the rear of the propeller.

3. In an aircraft including a propeller having a hollow hub and' a hollow shaft for driving said propeller, the combination of a gun adapted to shoot along the axis of the shaft of said propeller in forward direction, with a combined recoil compensating device and air resistance re ducer, said combined device and reducer comprising a substantially conical sheet metal member rigid with said aircraft and located in front of the propeller with its apex forwardly, said member having a hole therein for the passage of a projectile, portions of said member around the hole extending first forwardly inthe direction of the axis, then outwardly and away from the axis and then rearwardly to catch the force of the them rearwardly, the size of said member being such that its outer surface directs the air in a streamline with the outer surfaces of that portion of the aircraft directly to the rear of the propeller.

4. In an aircraft including a propeller having a hollow hub and a hollow shaft for driving said propeller, the combination of a gun adapted to shoot along the axis of said shaft in a forward directiony with a combined recoil compensating device and air resistance reducer located in front of the propeller and rigid with said aircraft and composed of two substantially conical members spaced from each other, both of said members having openings therein for the passage of a projectile, said members forming a rearwardly extending passage of annular cross section, the size of the outer member being such that its outer surface directs the air in a .streamline with the outer surfaces of that portion of the aircraft directly to the rear of the propeller.

5. In an aircraft including a propeller having a.hollow hub and a hollow shaft for driving said propeller, the combination of a gun adapted to shoot along the axis of said shaft in forward direction, said gun having an extension projecting forwardly of said propeller, with a combined recoil compensating device and air resistance reducer, said combined device and reducer comprising at least two substantially conical members located in front of theA propeller and spaced from each other, both ofv said members having openings therein for the passage of a projectile and -formingfa-rearwardly extending passage of annular cross section, the inner member being secured to. the extension on said gun' through which the projectile passes, and the outer member being secured tosaid inner member, the outer member being of such size that its outer surface directs the air in a streamline with the outer surfaces of that portion of the aircraft directly to the rear of the propeller.'

6. In a combination as defined in claim 4, a frusto-conical shield positioned between said device and the propeller and mounted to rotate with l