US2350777A - Aircraft back-turret cupola - Google Patents

Description

June 6, 1944. LANCIANI AIRCRAFT BACK-TURRET'CUPOLA Filed Sept. 20, 1940 7- TORE l mvc m/v/ BY \QW' ATTORNEYS.

Patented June 6, 1944 AIRCRAFT BACK-TURRET CUPOLA Ettore Lanciani, Milan, Italy; vested in the Alien Property Custodian Application September 20, 1940, Serial No. 357,514 In Italy September 25, 1939 3L Claims. (CI. 89-36) This invention is a novel aircraft back turret cupola, in the nature of a top enclosure or hood placed protectively above the rear gun turret of any type of aircraft, the combined turret and hood being adapted to enclose a machine gun or other firearm, as well as the gunner or operator thereof. The novel features of the invention may be disclosed without the need of illustrating the aircraft, or fuselage; and for that matter the gun turret itself need not be disclosed, except by reference to an illustrative gun'turret adequately shown in this applicant's copending application filed December 16, 1939, Serial No. 309,569 directed to Armed rotating turrets for aircraft, Fig. 1 of which in particular well shows such a gun turret, and machine gun, with a general indication of a covering hood or cupola protectively extending above the space accommodating the gun and gunner; the turret illustrated in the copending application being of the revoluble type so that, notwithstanding that the turret may be located near the rear of the aircraft, the gun may be swung leftward or rightward to a certain extent in aiming or following the target, while naturally the gun and mechanism also are trunnioned for upward and downward swing to adjust the firing elevation.

The general object of the present invention is to afford, especially for the rear gun turret for aircraft, a construction or physical shaping such as to afford important operational advantages. One such advantage is to afford superior visibility for the gunner. Another advantage relates to the matter of the relative wind, or rearward air flow about the aircraft, and has to do with the minimizing of the resistance of the turret and cupola to the wind, and the minimizing of eddies near the rear or tail side of the combined turret and cupola. Other advantages will appear from the hereinafter following description of an illustrative example of the invention.

In the accompanying drawing, Fig. 1 is a top plan view of a turret cupola or hood adapted to serve as a top covering for a revoluble gun turret such as shown in said application No. 309,569; this figure containing the direction arrow T to indicate the forward direction of travel of the aircraft, and the firing arrow F of the gun G, showing that it is mounted in a rear turret for firing oppositely to the direction of travel.

Throughout this description the line of direction of the arrows T and F, as shown, will be considered as the longitudinal direction, although naturally the turret may be swung through an extent of arc, to either side of the longitudinal, by the rotation of the turret and covering cupola. The circular shape of the cupola indicates its rotatable charactenabout the vertical axis V of the turret.

Fig. 2 is a longitudinal section view taken on the section line 2-2 of Fig. 1, slightly on the near side of the longitudinal diameter.

Fig. 3 is a similar longitudinal section, taken on the line 3-3 of Fig. 1, subtending a somewhat shorter chord.

Fig. 4 is a transverse sectional view taken on the section line 4-4 of Fig. 1, certain parts to the right thereof being seen in interior view.

Fig. 5 is a section taken on a. shorter chord, namely on the section line 5--5 of Fig. 1.

The cupola or hood thus illustrated may be considered as adapted to be set down'in covering position upon a rotatable or oscillating cupola such as that illustrated in said application No. 309,569, with a suificient arching or crowning of the covering cupola to accommodate the machine gun, directed rearwardly, and the gunner facing rearwardly, usually with the gun at his righthand side, and the ammunition feeding mechanism at the other side of the gun. The mode of mounting the cupola upon the turret, and its attachment there, are deemed unnecessary to indicate since the present invention is concerned not with such details but with the structure and shape of the cupola itself, as will next be described.

The cupola is seen to comprise a walled structure, the general portion 1 of which is of generally round outline and thus adapted to be placed upon the turret to cover the enclosed gun and gunner, and such general wall of the cupola being of generally arched, cambered or crowned shape, with its longitudinal sections generally of substantially airfoil or streamline contour. For illustration, two such longitudinal sections have been illustrated in Figs. 2 and 3 where it will be seen that, except for a minor interruption to be described, the cambered shape is of airfoil or streamline contour, comprising at its front portion or end an enlarged bulbous shape 8, passing around to a peak somewhat forward of the center, and thence with tapering away shape 9 toward the rear or tail end of the section. With the same exception, the transverse sections are of generally convexly arched curvature, and preferably substantially symmetrical, as best shown in the diametral section view Fig. 4. The curvature of the transverse section shapes is shown as involving a convenient polycentric of its rear portion, preferably within a quadrant 7' as shown, is shaped into a reentrant recess'or wall or shield affording effective rear vision, this wall being transparent or windowed. This special structure is well illustrated in all of the figures of the drawing, the sunk wall'portionor depression comprising, in the illustrated case, a substantially fiat or horizontal wall part I0, from the front edge of which extends a slanting wall II,' the upper edge of which isconnected or integral with the general arched wall I of the cupola. As'best shown in Fig. 3 the wall part II is steeply in-. clined, being shown at about 45; and it is. in the nature of a windshield, either wholly transparent, or having :a window l3 through which the gunner is afiorded a clear rearward view for aiming and firing purposes, I

In addition .to the fiat wall I0, and-the inclined wall H, the recessed shape of the cupola is bounded by a triangular upstandingwall M, see more especially Figs. 2 and 5, thetop of which connects or merges with the general wall portion I, and the other edges of which'are united with the wall portions Wand II respectively. By. this shaping the entire interior is enclosed and protented from exposure and weather.- The three walls 10, H and M are preferably plane. 1 The following general arrangement is preferred. The gunner sits behind the vision wall l'l looking rearwardly, at the left part of the enclosed space, while the gun'preferably is 10- V '10 depression, which breaks into but mergeswith the arched general curvature of the cupola, and I such depression comprising a steeply inclined;

cated to the right of the upright wall It, and

for this :purpose the general wall or shell portion I of the cupola is cut away to form an aperture 12, in the nature of an elongated slot permitting up-and-down swinging of the-gun in training it upon the target.

While the describeddepression parts of the cupola wall, which may be struck from the general material, constitute somewhat of an interruption, at one rear quadrantoi the streamline contour; the loss of airfoil effect -isminimized, by the fact that'the wall I! slants downwardly and V rearwardly, and to some extent preserves the desired contour to minimize air resistance and 'eddying, as is clearly seen by comparison of Figs.

2 and 3.

Naturally theexact constructional shape and details may be considerably varied without departingfrom' the principles described, and. it is notintended to limit the invention to. the illustrative disclosure of the drawing.

'What is claimed isz a 1. A cupola for arr-aircraft rear gun turret, comprising awalled structure having a generally circular outline adaptedtto be .placed over-the turretto ccverthegun and the gunner; said cupola structure being characterized in having its wall of generally cambered shape and wherein the wall at oneiside of its rear portion is shaped into a' reentran-t depression breaking but merging with the arched general curvature of the quadrant-l of the cupola: and whereinan opening is providedain the adjacent rear quadrant through I whicha gun may be-fired.

3. The structureset-forth in claim- 1 wherein the base of the depression-is substantially'flat and in the plane of the. air foil tipand .thein-' clined wall makes an angle with ,the extension of suchplane of approximately said depres.

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