Flight, January 31, 1918.
THE UNITED EASTERN TRACTOR BIPLANE.
DURING the latter part of 1917, the United Eastern Aeroplane Corporation of Brooklyn, N.Y., U.S.A., turned out several very successful training tractor biplanes, a description of which, together with illustrations and scale drawings, we give herewith. The Eastern tractor has been designed strictly to Government specifications, and is, we are informed, specially noteworthy as regards workmanship and finish.
The main planes are built up in five sections, two being attached to a smaller central section or panel, supported above the fuselage by four struts, comprising the top surface, and two attached direct to the fuselage, forming the lower surface. Eiffel No. 36 wing-section has been selected on account of the high L/D ratio, giving quick climb and high loading at comparatively slow speed. The planes are given a dihedral angle of 1° and the top plane is staggered forward about 4 ins. The normal angle of incidence is about 3°. The planes are built up in the conventional manner of spruce, spars and ribs of the lightest possible section. Two pairs of streamlined struts separate top and bottom planes on each side of the fuselage. The bracing is of Roebling steel cable doubled in the centre sections. Drift wires are taken from the forward ends of the upper fuselage longerons to the top of the front inner interplane struts, and from the forward ends of the lower longerons to the lower ends of the same interplane struts. The outer portions of the top plane extending beyond the interplane struts are braced from kingposts above these struts. Lateral control is obtained by means of a pair of interconnected ailerons, each 16 sq. ft. area, hinged to the top plane rear spar. The chord of these ailerons increases towards the tips, where the trailing edge is given a slight up-turn.
The horizontal stabilising plane, 36 sq. ft. area, is of one piece construction, with raked ends and rounded corners. It is of the flat cambered, non-lifting type, and is mounted on the top longerons of the fuselage. The elevator is divided into two flaps, with the rudder working in between, and is constructed of steel tubing with wood ribs. The rudder, which is of distinctive shape, is partly balanced by a small surface forward of the pivoting post, and has an area of 15 sq. ft. The controlling surfaces are operated by standard dual stick and rudder-bar control.
The fuselage is of standard construction; wooden members and metal fittings, braced with piano wire and Roebling cable, doubled at the forward section. It is built up in two sections, being joined immediately behind the rear cockpit. It is rectangular in section, tapering to a vertical knife-edge at the rear, having a maximum width and depth of 2 ft. 3 ins. and 3 ft., respectively. The forward portion, enclosing the engine, and the top turtle deck as far back as the rear cockpit is covered with sheet aluminium, the remainder of the fuselage being fabric covered. The cockpits are made as comfortable as possible, being well upholstered.
A two-wheel type landing gear is fitted, the wheels being 26 x 4 ins. The axle, which is of 1 3/4 in. chrome nickel steel, is mounted by means of rubber shock absorbers on a pair of laminated ash hockey-club shaped skids. A vertical strut both fore and aft of the axle on each skid connect the latter with the fuselage. The two forward chassis struts are connected by a horizontal tie rod, and the chassis is cross wire braced at this point. The wheel track is 5 ft. 3 ins. Rattan hoop-skids are mounted on the lower wing tips, just below the outer interplane struts, and a swiveling skid is located under the tail.
The power plant consists of a Curtiss 90 h.p. OX-5 8-cyl. V, coupled direct to an 8 ft. 3 ins. tractor screw. Mounted in the nose of the fuselage, immediately in front of the engine, is the radiator weighing 55 lbs. There are two petrol tanks, a small gravity tank of 5 gals, capacity located under the engine cowling, and a main tank containing 30 galls, under the front seat.
The gravity tank is fed by pressure obtained from an air pump worked by the motor. A hand pump is also provided.
The principal characteristics of the Eastern tractor are: span, upper 41 ft., lower 32 ft. 7 ins.; chord, 5 ft. 3 ins. ; gap 5 ft. 6 1/2 ins.; stagger, 4 ins.; dihedral, 1°; angle of incidence, 3°; wing section, Eiffel 36; overall length, 27 ft.; overall height, 10 ft. 6 ins.; total area of main planes, 390 sq. ft.; speed range (full load), 40-75 m.p.h.; climb, 4,000 ft. in 10 mins.; gliding angle, 1 in 7.
Sweep back 8
Area 350 sq. ft.
Ailerons Upper planes
Landing gear 2 wheels
Engine Curtiss 100 h.p. (OXX.2)
Weight with one hour's fuel 1200 lbs.
Useful load 800 lbs.