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11/20/2004. Remarks by Ian Dunster, from Helicopters 1900-1960, by Bill Gunston and John Batchelor: "Experimental heavy-lift helicopter first flown in October 1952.Turbojets provided compressed air for blade-tip pressure jets. The XH-17 had enormous potential but its range was too short to be practicable. Engines: two GE J35 turbojets Weight fully loaded: 52,000 lb Cruising speed: 60 mph Range: 40 miles Number of seats: 2 By far the most impressive of all rotor-craft in the early 1950s was a strange monster designated XH-17. This was planned and taken through the design process by Kellett, but hardware trials were transferred to Hughes Aircraft at Culver City. Already the aircraft firm of billionaire Howard Hughes had a reputation for being quite undeterred by the most formidable development problems, and certainly the XH-17 made sense on paper. In any case, it was part-funded by the USAF. It was a flying crane, the specialized category pioneered by the German Fa 284 and intended to lift cargo weighing up to 27,000 lb (12,247 kg) more than ten times as much as any other rotorcraft of its day. To do so it had a radically new form of lift power. There was not very much to the XH-17 apart from the gigantic two-blade rotor, with a diameter of 136 ft. This was carried on a stubby but lofty structure, on a tall multi-wheel landing gear. On each side was a General Electric TG-180 turbojet, later redesignated J35, modified so that instead of giving just jet thrust it supplied an enormous flow of compressed air, tapped off through a large duct between the compressor and combustion chambers. The air trunks led up to the mighty rotor hub and then delivered the air along the hollow blades to General Electric GE33F pressure-jet burners arranged along the outer part of each blade. Here fuel was injected and burned for VTOL, though it was hoped fuel burning at the tips could be reduced or even eliminated in cruising flight. The giant machine spent 1949-51 in ground tests and then made a successful free flight on 23 October 1952. Eventually plans for the projected production version, the H-28, were cancelled. The limiting range of around 40 miles was a great handicap, because the XH-17 was too big to be airlifted at that time and thus had to fly to wherever it was needed or travel by ship. But it was bigger and had more rotor power than any helicopter since built outside the Soviet Union. View also photo 8115."