Flight, October 1922

THE 1922 PULITZER TROPHY RACE

   The Curtiss Machines. - The Curtiss fleet consisted of a Navy racer, biplane, and a racing triplane, entered by the U.S. Navy, and two Army racers, entered by the U.S. Army. An outstanding feature with three of these machines may be said to consist of the employment of wing-radiators - radiators built into and following the contour of the wing itself - instead of the usual type of water-cooling radiators. We refer to this again later. The Navy racer is similar to the type which won last year's Pulitzer race, but with certain modifications, and improvements. These two machines differ only in that one year's model is fitted with Lamblin radiators, mounted on the landing chassis, whilst the other is equipped with the wing type radiator. The fuselage, of Curtiss-ply construction, is carefully streamlined and of the minimum cross-sectional area. The wings are of multi-spar construction, with Curtiss-ply covering. The petrol tank is mounted between the top plane and the fuselage, and is streamlined. A Curtiss CD.12, 12-cylinder engine is fitted, which develops 400 h.p. at 2,000 r.p.m. A simplified oiling system, reducing the number of tanks and parts to a minimum, is employed, in addition to an improved type of oil cooler, which maintains a constant oil temperature, low enough to permit the engine to deliver its maximum horse-power at full throttle. Aluminium and duralumin have been made use of to the fullest possible extent, including in many instances piping, tanks, fittings, etc. The principal characteristics of the Navy Racer are as follows :- Span (overall), 22 ft. 8 ins.; length, 21 ft.; height, 8 ft. 11 ins.; chord, 4 ft.; gap, 4 ft.; stagger, 1 ft. 3 ins.; wing section, Sloan; angle of incidence, 0°; dihedral (lower), 2°; total wing area, 168 sq. ft.; area of ailerons, 18 sq. ft.; 2 sq. ft.; tail plane, 12-6 sq. ft.; fin, 4.8 sq. ft.; sq. ft.; weight empty, 1,735 lbs.; weight laden, loading/sq. ft., 12-5 lbs.; loading/h.p., 5-24; speed range, 70-190 m.p.h. It is estimated that with the wing-radiators an increase in speed of 10 m.p.h. is obtained.
   The Army Racers are the latest development of Curtiss practice. The fuselage is of Curtiss-ply, a strong light 2-ply veneer of laminated spruce, 3/32-in. thick, and like the Navy Racer, well streamlined. The weight of the fuselage complete is only 127 lbs. The projected area of the fuselage is 25 per cent, less than that of the Navy Racer, which won last year's race. The wings are multi-spar, Curtiss-ply covered, with wing-radiators. These latter consist of corrugated sheet brass radiator surfaces which replace the wing covering, top and bottom, maintaining the true shape of the wing section. The flow of air around the wings thus cools the engine water without any extra head resistance. It may be of interest to note this type of radiator was developed by the Curtiss Co. during the last two years, and has been given a thorough "try-out," on one occasion a cross-country flight of about 1,500 miles at an average speed of 100 m.p.h. being made by a Curtiss "Oriole" fitted with this radiator.
   The Army Racer has single I-inter-plane struts, and the fixed tail surfaces are of the Curtiss-ply cantilever construction, without any external bracing. The control surfaces - ailerons, elevators and rudder - are of steel and duralumin, with fabric covering, and are all operated by means of internal cables and tubes. The wing section employed is the Curtiss No. 27. A Curtiss D. 12, 375 h.p. 12-cylinder V engine is fitted. By the employment of the single-strut type of landing chassis the resistance of this unit has been reduced two-thirds, whilst, retaining the strength and rigidity of the conventional V-chassis. The wheels are provided with cupped discs of aluminium which cover the spokes and hub, and a fabric covering is applied over the wheel and tyre in such a manner that a smooth oval section is presented to the air stream. The axle is enclosed in a lifting section fairing, 7 sq. ft. area.
   Characteristics : Span, 19 ft.; length, 18 ft. 11 ins.; height, 7 ft. 10 ins.; chord, 3 ft. 10 ins.; gap, 3 ft. 10 1/2 ins.; stagger, 7 1/2 ins.; angle of incidence, 0°; no dihedral; total wing area, 131 sq. ft.; area of ailerons, 9-25 sq. ft.; tail plane,, 11-2 sq. ft.; elevators, 9-2 sq. ft.; fin, 4-9 sq. ft.; rudder, 4-9 sq. ft.; weight empty, 1,454 lbs.; weight laden, 1,950 lbs.; loading/sq. ft., 14-1; loading/h.p., 5-2 lbs.; speed range, 70-200 m.p.h.