Flight, January 1922
THE FRIESLEY "FALCON" CABIN BIPLANE
WE give below some particulars, with accompanying illustrations, of an American-built 12-passenger twin-engined Liberty (low-compression) biplane, the Friesley "Falcon." This machine, which is of the enclosed
cabin type, made its first public lest flight last April at Friesley Field, California, piloted by B. M. Spencer (late of the U.S. Air Service), who was also responsible for the designing and building of the machine.
The "Falcon" left the ground after a run of less than 100 yards at a speed of 45 m.p.h., and during its flight developed a speed of 90 m.p.h. with the engines throttled to 1,500 r.p.m. The balance proved to be perfect, and the ease of control, glide and landing exceeded the expectations of the designer. It landed at 40 m.p.h., and came to rest after a run of less than 200 ft. Only two private test flights had been carried out previous to this one, on the day before, each of about two minutes' duration.
The cabin, formed by the fore half of the fuselage, is completely enclosed, and contains twelve wicker seats, arranged in two rows in tandem, with a space of 20 ins. between each seat. As the cabin has a clear width of 4 ft. 8 ins., there is thus a wide aisle down the centre. There is plenty of room for the passengers to stand erect, the height of the cabin being 5 ft. 8 ins. The cabin may readily be adapted for freight or mail work, and there being no cross-bracing of any description a large clear space is provided. The pilot's cockpit is in the extreme nose, and as this portion of the cabin extends out a considerable distance forward of the wings, the visibility is exceptionally good. Large windows are provided all round the sides of the cabin, and celluloid ports are also fitted in the roof, giving the pilot a good view overhead. All instruments are arranged on a desk immediately in front of the pilot, and under this desk, readily accessible, are the storage batteries for the engines.
Aft of the passengers' section is a luggage compartment measuring 4 ft. by 5 ft. by 4 ft.
Longerons of solid spruce are used for the fuselage, from nose to tail post, with bolted-on tie wire fittings. A hard wood block, glued and screwed and finally covered with tape, is placed where the fittings fasten to the longerons. Fuselage truss wiring is made up of 3/16-in. 3 per cent, nickel steel rods, threaded right and left hand, and terminating in forks on each end.
The fuselage is covered with plywood from the nose to a point immediately at the rear of the luggage compartment of the cabin, and from a point slightly forward of the tail skid to the stern post. The intermediate portion of the fuselage is covered with fabric. The tail skid is of steel tubing hung to a frame, also made of steel tubing, that fastens to all four longerons; the shock is taken by rubber cord.
One of the most unique features of construction in the "Falcon" is to be found in the rudder control. Instead of the conventional flapping wires running into the fuselage, the control is conspicuous by its absence of exposed wires. Fastened to the rudder are short horns on which are pivoted two rods, which terminate in a semi-circular sliding yoke of steel tubing, that slides back and forth through a fitting mounted on the tail post. This yoke is actuated by the rudder control wires, which are completely enclosed. This allows a very clean-cut tail structure, and offers a minimum of resistance. The elevator control wires pass out of the tail and lead directly to the horns on the elevator - the total amount of exposed control wire being only about 2 ft. on each side. Rudders and ailerons are balanced. The stabilizer is adjustable by means of two screws controlled from the pilot's seat by a hand wheel.
Fuel is carried in tanks situated under the floor of the cabin, and is pumped from the.se to a gravity tank of 40 gals, capacity, located on the top plane above each engine. The overflow is fed back through sight gauges in the pilot's cockpit. The oil tanks are situated on the engine bearers immediately behind the engine.
The engines are 12-cyl. low-compression Libertys, mounted midway between the planes, somewhat forward of the leading edge, and driving Paragon tractor screws of 9 ft. diam. by 7 ft. pitch.
A substantial landing gear is fitted, consisting of the double-yoke type housing a pair of Atlas spring wheels, there being one unit immediately under each of the power plants. Elimination of shock absorber cord and of the weakness of construction where this is employed are the features of this under-carriage.
The principal characteristics of the "Falcon" are as follows :-
Span 65 ft. 3 ins.
Overall length 40 ft.
Overall height 15 ft.
Chord 7 ft. 6 ins.
Gap 7 ft. 6 ins.
Wing section U.S.A. 5
Angle of incidence (top) 3 deg
Angle of incidence (bottom) 2 deg.
Area of main planes 897 sq. ft.
Area of ailerons (4) 120 sq. ft.
Area of stabilizer 53 sq.ft.
Area of rudders (2) 33-2 sq. ft.
Area of fins 26 sq. ft.
Weight of machine empty 5,600 lbs.
Weight of machine loaded 8,600 lbs.
Weight, sq. ft. 9-3 lbs.
Weight, h.p 12-3 lbs.
Speed range 55-120 m.p.h.
Climb to 5,000 ft. 4 mins.