Flight, November 23, 1916.
THE BURANELLI-CARISI "PUSHER" BIPLANE.
SEEING that America has not done very much in the way of "pusher" biplanes of the headless nacelle type, and inasmuch as the gun 'bus is claiming no small amount of attention from designers at the present moment, special interest attaches to the machine, recently designed in America, illustrated in the accompanying scale drawings. This machine has been jointly designed by Mr. Vincent J. Buranelli and Mr. John Carisi, and was built some little time back in New York.
Although the Buranelli-Carisi, or "A.B.C." biplane, as it is named for the sake of brevity, might be said to belong to the Henry Farman type of biplane, it really differs from it in some of the essential features, i.e., the main planes are swept back, the top plane has a considerable overhang, and only one pair of interplane struts on either side of the nacelle separate top and bottom planes. There are, of course, other less radical differences in minor details.
The top plane has a span of 40 ft. and a chord of 5 ft. 6 ins., whilst the lower plane has a span of 22 ft. and a chord of 4 ft. 6 ins., and both are swept back 10°. The trailing edges of both top and bottom planes are in line, thus giving the effect of staggering the planes. The planes are divided into five sections, two lower and three upper. The lower plane sections are mounted direct on to the nacelle, whilst the two innermost sections of the upper plane are anchored to two inverted V pylons of spruce struts mounted on the nacelle. All the mountings of these different sections are of the hinged quick detachable type, facilitating transport. The upper plane extensions measure some 12 ft. each, being braced by Roebling cable of 4,000 lb. tensile strain from pylons mounted on the extremities of the inner plane-sections above the interplane struts. A rather unusual feature for a machine of this type is that lateral balance is maintained by warping the top-plane extensions instead of employing ailerons.
The planes are built up on solid I section spars with built-up ribs of similar section. The front spar of the upper plane is situated close to the leading edge, and the rear spar some distance from the trailing edge, whilst in the lower plane the front spar, which like the rear spar is of substantial width, forms the leading edge itself. Both top and bottom planes are wire braced between the spars, and Irish linen doped with Emaillite is used for the covering. The interplane struts, of spruce, are exceptionally strong and well streamlined. A wing-section giving high speed and maximum lift is employed.
The tail planes are similar in form to those on the Henry Farman, being carried in the same way by four outriggers of 1 1/8-in. steel tubing with wood struts, vertical and horizontal. The forward ends of the top outriggers are attached to the top of the upper plane rear spar, just above the interplane strut, and the rear ends come to a point at the vertical post to which the rudder is pivoted. The latter, it will be seen, is slightly staggered forward, somewhat on similar lines to the first Vickers gun-'bus exhibited at the 1913 Olympia Show. The lower outriggers are similarly mounted on the lower plane. The horizontal stabilising plane is mounted on the top outriggers, and has an area of 27 sq. ft. The elevators, measuring 2 ft. by 5 ft., are hinged to the trailing edge of the stabilising plane, one on either side of the rudder, which is of 10 sq. ft. area and partly balanced. The attachment of the stabilising plane is by special fittings which allow different angles of incidence to be made. The construction of the various tail surfaces follows that of the main planes.
The nacelle is deep and roomy, and well streamlined. It is built up of stout longitudinals, and struts, in such a manner that they serve as bracing members, thereby dispensing with wire bracing. It is about 10 ft. in length, 3 ft. wide and 3 ft. 6 ins. maximum depth. The engine is mounted on strong ash bearers at the rear. The nose of the nacelle is formed by the radiator, which is of the pointed or "Metallurgique" type. Behind are the pilot's and passenger's seats arranged side by side, in front of which is provision for mounting two machine guns. The nacelle is covered with Duralumin throughout Formed integral with the nacelle, the fuel tank has a capacity of 40 gallons of petrol, which is force-fed to the engine. The latter is of 100 h.p., having four vertical cylinders, and has been designed by Mr. Buranelli and Mr. Carisi on the lines of the Austro-Daimler engines.
The landing chassis is of the four-wheel type, and appears to be exceptionally strong. The two main wheels, measuring 26 ins. by 4 ins., are mounted under the lower plane, being supported in two stout struts by rubber shock absorbers. Two skids, each connected to the nacelle by a second pair of struts, extend from the main wheels, and carry at their forward extremities the two smaller wheels which prevent the machine from turning over on its nose in the event of a bad landing. Both pairs of wheels are mounted on tubular axles, and the skids are connected by a cross strut, which, together with the wire bracing considerably strengthens the undercarriage.
The control is on Nieuport lines, a wheel, operating the rudder, mounted on a rocking column which operates the elevators, whilst warping is effected by a foot bar.
The calculated speed is given as 40 to 70 m.p.h., and some promising results should be forthcoming from this machine.