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Aviation History
1953
1953 - 0114.PDF
H2 FLIGHT, 23 January 1953 The World's Helicopters WEIGHTS 2,500 to 6,000 lb (cont.) Kaman HTK-1. JACOBS 104 • Of quite unconventional form, this five- seater is the maiden effort in the helicopter field of the Jacobs Aircraft Engine Co., of Pottstown, Pennsylvania. The engine is a Jacobs R-755-E, which drives a single main rotor, anti-torque tail rotor, and pusher propeller; the latter intermeshes with the anti-torque rotor—a unique instance. As the drawing on the previous page shows, a swept-back wing is another unorthodox feature. A carefully studied combination of the engine and trans mission system is expected by the makers to result in a valuable weight-saving. Normal empty and gross weights are estimated as 1,972 lb and 3,258 lb. At the latter weight the maximum speed is estimated to be 186 m.ph.; cruising speed, 150 m.p.h.; endurance, 4 hr at 138 m.p.h.; and vertical rate of climb, 1,130 ft/min. KAMAN HTK-i • This three-seat trainer, adopted by the U.S. Navy, is a product of the Kaman Aircraft Corporation, of Bradley Field, Windsor Locks, Conn. Powered by a Lycoming O-435 engine of 235 h.p., it is a development of the civil model K-225, later described, differing from that machine in rotor blade design and in having a tailplane interconnected with the collective pitch control. As an ambulance the HTK-i carries a stretcher case and attendant or two "sitting" cases in the fuselage and two stretcher cases in external litters. KAMAN HOK-i • This is a new four-seater liaison heli copter for the U.S. Navy, the appearance of which is shown in the accompanying photograph of a model. It will be seen that, as in the HTK-i, the twin two-blade rotors are of intermeshing type. Constructional and performance details are withheld, but the gross weight will be about 3,500 lb. This type was selected from several submitted for a U.S. Navy competition. KAMAN K-225 * A three-seater utility helicopter, this model is normally powered with a 225 h.p. Lycoming O-435 engine, though an experimental development, a photograph of which is reproduced on this page, has been fitted with a 175 h.p. Boeing 502-2 gas turbine engine. This flying test bed was, in fact, the first helicopter to fly with turbine-driven blades and results are considered encouraging. The two-blade contra-rotating intermeshing rotors are of solid spruce and are fitted with servo flaps, which eliminate the blade pitch-change bearings. By means of these flaps the blade is twisted between the root and a point at three-quarters radius, where the flap is located, use being made in this connection of the natural resilience of the spruce blade. The standard K-225 has the following characteristics: weight empty, 1,800 lb; normal gross weight, 2,700 lb; max. speed, 73 m.p.h.; max. rate of climb, 1,000 ft/min; hovering ceiling in ground cushion, 6,000ft; absolute ceiling, 12,000ft; autorotative rate of descent, approx. 1,250 ft/min. Kaman HOK-1. Sikorsky S-5J (amphibian landing gear).
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