Flight, October 1935

TEMPTING the U.S. PRIVATE OWNER
The Curtiss Sparrow: Stressed Skin: Fixed Slots: 131 m.p.h. on 90 h.p.

   AS regular readers of Flight will know, the American Bureau of Air Commerce, under the direction of Mr. Eugene Vidal, has been sponsoring a scheme by which the citizens of America would be able to purchase a small, low-priced, safe aeroplane. The contribution to this scheme of the Curtiss-Wright Airplane Co., of St. Louis, Missouri, is the Sparrow, a side-by-side two-seater, all-metal, stressed-skin, low-wing, cabin monoplane which bears a striking resemblance in appearance to the latest high-speed single-engined transport machines.
   The gauges of the metal skin used throughout are the same as those used on commercial types of much greater weight, the material being 24ST Alclad.
   Five spars are embodied in the full cantilever wing, the skin of which is designed to carry the loads. In order to improve lateral control, the ailerons, which are of metal construction, are locked against downward travel past their neutral position This is accomplished by a combination of an idler link in connection with the control rod whereby the pulleys are made to rotate idly when the aileron reaches the neutral position on its downward travel, even though it is rigidly and directly connected with the opposite aileron control mechanism. The attachment of the aileron to the wing is accomplished by a full-length piano-type hinge.
   A split flap extends over 70 per cent, of the wing span, and is operated by a rotating handle located at the pilot's right hand near the bottom of hi» seat. Unlike more conventional flap-actuating mechanisms, this is so operated through torque tubes that the load on the handle remains almost constant regardless of air load. The mechanism is attached to the flap at five points, each position being adjustable.
   Another outstanding feature is the provision of permanently open slots formed by placing auxiliary aerofoils above, and ahead of, the main wing. It may be recalled that tests with a similar arrangement on a Fairchild F.22 monoplane during 1933 gave an increase in lift coefficient from 0.675 to 0.98.
   Of all metal monocoque construction, the fuselage consists of raised rings, stringers and skin assembled as in modern American transport machines. The side-by-side two-seater cabin is fitted with dual controls, the right-hand set being easily removable. There is a sloping windscreen, side windows, and a large transparent panel in the roof. Two car-type ventilators are installed in the top of the windscreen, and there are two rear view mirrors. The ventilators are of the type which suck air from the cabin, fresh air being taken in through a duct opening in front of the engine, assuring pure, uncontaminated air. Two large doors, one on each side, give access to either front seat. The seats are fitted with spring cushions, and are adjustable fore, aft and vertically.
   The flying controls are conventional in design except for the fact that the control column is used in an inverted position.
   Both tailplane and fin are fixed, but there are metal trimming tabs on the elevator operated by a Breeze irreversible mechanism. The elevator and rudder (and, in fact, the whole of the empennage) are of metal construction, the elevator hinge being of a piano type extending from the tip to the root.
   Monocoque "trousers" enclose the undercarriage mechanism. Full air wheels are used, and the oleo legs have a 10in. stroke. The gear is held in the take-off position by a small latch embodied in the oleo leg which is automatically released on the first turn of the flap. Hydraulic brakes both of the foot and parking type are incorporated. The parking brake is a simple sliding control on the instrument board.
   A 90 h.p. Lambert K-266 5-cylinder radial is mounted on a steel tubular structure, the engine itself being supported with rubber bushings to absorb vibration
   The maximum fuel capacity of the Model 19L Sparrow is 43.3 gallons carried in two tanks located on each side of the fuselage in the wing. Five gallons in the left tank are held in reserve. The oil tank, of 4.2 gallons capacity, is attached to the fireproof bulkhead directly behind, the engine.

CURTISS-WRIGHT SPARROW.
Two-seater Light Monoplane.
Lambert R-266 Engine, 90 h.p.

DIMENSIONS.
   Span 35ft.
   Length 25ft. 6 1/2 in.
   Height 7ft. 2in.
   Wing area 174 sq. ft.

WEIGHTS AND LOADINGS.
   Weight empty 1,154 lb.
   Disposable load 646 lb.
   Gross weight 1.800 lb.
   Wing loading 10.3 lb./sq.ft.
   Power loading 19.9 lb./h.p.

PERFORMANCE.
   Maximum speed 131 m.p.h.
   Cruising speed 115 m.p.h.
   Initial rate of climb 500 ft./min.
   Stalling speed 44 m.p.h.
   Ceiling 17,000ft.
   Cruising range (normal) 496 miles.
   Cruising range (maximum) 1,150 miles.
   Fuel consumption at cruising speed 4.7 gall./hr.