This article includes alist of references,related reading,orexternal links,but its sources remain unclear because it lacksinline citations.(July 2014) |
TheHughes XH-17 "Flying Crane"was the firsthelicopterproject for thehelicopter divisionofHughes Aircraft Company.The XH-17, which had a two-bladed main rotor system with a diameter of 134 feet (41 m), still holds the world record for flying with the largest rotor system. It was capable of flying at a gross weight of more than 50,000 pounds (23,000 kg), but proved too inefficient and cumbersome to be mass-produced beyond the prototype unit.
| XH-17 "Flying Crane" | |
|---|---|
 | |
| General information | |
| Type | Helicopter |
| Manufacturer | Hughes Helicopters |
| Status | Scrapped |
| Number built | 1 |
| History | |
| First flight | 23 October 1952 |
| Retired | December 1955 |
Design and development
editThe XH-17 was a heavy-liftrotorcraftthat was designed to lift loads in excess of 15 metric tons. To speed construction, parts of the XH-17 were scavenged from other aircraft. The front wheels came from aNorth American B-25 Mitchelland the rear wheels from aDouglas C-54 Skymaster.The fuel tank was a bomb bay-mounted unit from aBoeing B-29 Superfortress.The cockpit was from aWaco CG-15military glider and the tail rotor from aSikorsky H-19 Chickasawwas used for yaw control.
In the late 1940s,Hughesdeveloped an interest in helicopters. In August 1947, helicopter manufacturerKellettsold his design for the giant XH-17 Sky Crane to Hughes, who commissioned the development of the XH-17 Flying Crane research vehicle. In 1948, the XH-17 began to take shape. The giant helicopter was tested in Culver City, California over a three-year period beginning in 1952. The XH-17 flew in 1953 at a gross weight in excess of 50,000 pounds (23,000 kg). It still holds the record for flying with the world's largest rotor system. Only one unit was built, since the aircraft was too cumbersome and inefficient to warrant further development.
The propulsion system was unusual. TwoGeneral Electric J35turbojetengines were used, sendingbleed airup through the rotor hub. The blades were hollow, and the hot compressed air traveled through the blades totip jetswhere fuel was injected. In flight, the main rotor spun at a sedate 88 revolutions per minute, less than half the speed of typical helicopter rotors. Since the rotor was driven at the tips rather than the hub, littletorquecompensation was required, mostly due to friction in the main rotor bearing. Thus, the XH-17 had a very smalltail rotorcompared to its main rotor. This drive system was inefficient, limiting the test aircraft to a range of only 40 miles (64 km).
TheXH-28was a derivative, with a maximum weight of 104,000 pounds (47,000 kg). Though a wooden mockup of the design was made, the program was canceled and none were built.
Specifications
edit
Data fromMcDonnell Douglas aircraft since 1920 Vol.2[1]
General characteristics
- Crew:3 (pilot, mechanic and in-flight test engineer)
- Capacity:demonstrated loads up to 10,284 lb (4,665 kg) were carried
- Length:53 ft 3.6 in (16.246 m)
- Height:30 ft 1.2 in (9.174 m)
- Empty weight:28,562 lb (12,956 kg)
- Gross weight:31,270 lb (14,184 kg)
- Max takeoff weight:43,500 lb (19,731 kg)
- Fuel capacity:635 US gal (529 imp gal; 2,404 L) (Boeing B-29 bomb-bay tank)
- Powerplant:2 ×General Electric 7E-TG-180-XR-17Agas generators, 3,480 hp (2,600 kW) each combined predicted gas power output, with rotor turning at 88 rpm
- Main rotor diameter:130 ft (40 m)
- Main rotor area:13,274.95 sq ft (1,233.283 m2)
Performance
- Maximum speed:90 mph (140 km/h, 78 kn) at 8,000 ft (2,438 m)
- Cruise speed:85 mph (137 km/h, 74 kn)
- Range:30 mi (48 km, 26 nmi) with 10,284 lb (4,665 kg) payload
- Service ceiling:13,100 ft (4,000 m)
- Rate of climb:1,650 ft/min (8.4 m/s)
- Disk loading:2.4 lb/sq ft (12 kg/m2)
- Power/mass:0.111 hp/lb (0.182 kW/kg)
See also
editAircraft of comparable role, configuration, and era
References
edit- ^Francillon, René J. (20 September 1990).McDonnell Douglas aircraft since 1920 Vol.2(2nd ed.). London: Putnam Aeronautical. pp. 131–135.ISBN978-0851778280.
Further reading
edit- Winchester, Jim (2009).World's worst aircraft.New York, NY: Rosen.ISBN978-1404218376.
- "Giant Jet Helicopter Ready For First Flight".Popular Mechanics:116. August 1952.
- "HOW FARES THE HELICOPTER?.".Flight.70(2493): 710–716. 2 November 1956.
- "A Spread of Giants".Flight.69(2450): 15. 6 January 1956.
External links
edit
- "Hughes XH-17".1000aircraftphotos.Retrieved14 August2020.