Hughes XH-17

Infobox Aircraft
name = XH-17 "Flying Crane"



caption =
type= helicopter
manufacturer= Hughes Helicopters
designer=
first flight= 23 October 1952
introduced=
retired= December 1955
status= Scrapped
primary user=
more users=
produced=
number built= 1
unit cost=
variants with their own articles=

The XH-17 "Flying Crane" was the first helicopter project for the helicopter division of Hughes Aircraft. The XH-17, which had a two-bladed main rotor system with a diameter of 134 feet, was capable of flying at a gross weight of more than 50,000 pounds.

Design and development

The XH-17 was a heavy-lift rotorcraft that 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 a B-25 Mitchell and the rear wheels from a C-54 Skymaster. The fuel tank was a bomb bay-mounted unit from a B-29 Superfortress. The cockpit was from a Waco CG-15 and the tail rotor from a Sikorsky H-19 was mounted on a tubular fuselage extension.

In the late 1940s, Hughes developed an interest in helicopters. In August 1947, helicopter manufacturer Kellett sold his design for the giant XH-17 Sky Crane to Hughes. Howard Hughes Jr. commissioned the development of the XH-17 Flying Crane research vehicle. In 1948 aviation pioneer Howard Hughes, Jr. began to turn the giant XH-17 Flying Crane into a flying reality. The giant helicopter was flight tested in Culver City, Calif. over a three-year period beginning in 1952. The XH-17 flew in 1953 flew at a gross weight in excess of 50,000 pounds. It still holds the record for flying with the world's largest rotor system. Only one unit was built, since the behemoth was too cumbersome and inefficient to warrant further development.The propulsion system was highly unusual. Two turbojet engines were used, sending bleed air up through the rotor hub. The blades were hollow, and the hot, compressed air traveled through the blades to tip jets where fuel was injected. In flight the rotors were designed to spin at a sedate 88 rpm. Since the rotor was driven at the tips rather than by the hub, little torque compensation was required. Thus, the XH-17 had a very small tail rotor compared to its main rotor. This drive system was inefficient, limiting the test aircraft to a range of only 40 miles (64 km).

The XH-28 was a derivative, with a maximum weight of 47,000 kg. The program was cancelled and none were built.

pecifications

aircraft specifications

plane or copter?=copter
jet or prop?=jet

ref=

crew= 3 (pilot, mechanic and in-flight test engineer)
length main= 53 ft 3 in
length alt= 16.25 m
span main= 129 ft 11 in
span alt=39.62 m
height main= 30 ft 2 in
height alt= 9.17 m
empty weight main= 28,563 lb
empty weight alt= 12956 kg
loaded weight main= 31,270 lb
loaded weight alt= 14184 kg
useful load main= 10,284 lb
useful load alt= 4665 kg
max takeoff weight main= 43,500 lb
max takeoff weight alt= 19731 kg

engine (jet)= General Electric
type of jet= GE J35 turbojets
number of jets= 2
engine (prop)=
type of prop=
number of props=
power main= hp
power alt= kW
max speed main= 90 mph
max speed alt= 145 km/h
cruise speed main= 85 mph
cruise speed alt= 137 km/h
range main= 40 mi
range alt= 64 km
ceiling main= 13,100 ft
ceiling alt= 3995 m
climb rate main= 1650 ft/min
climb rate alt= 8.4 m/s
loading main= 2.34 lb/ft²
loading alt= 11.5 kg/m²
more performance=

ee also

aircontent
related=

similar aircraft=
* CH-54 Tarhe
* S-64 Skycrane

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External links

[http://www.youtube.com/watch?v=ZMJOS2VWaPU 1952 experimental aircraft newsreel] The XH-17 is shown at the end of the newsreel. It is also shown in flight, clearly illustrating the slow rotation speed of the rotor.

References

* http://www.1000aircraftphotos.com/Contributions/VanTilborg/3138.htm
* http://findarticles.com/p/articles/mi_qa3897/is_200104/ai_n8943768
* http://avia.russian.ee/helicopters_eng/mcdonnel_crane.phpJim Winchester "The World's Worst Aircraft", 2005
Rene J. Francillon "McDonnell Douglas Aircraft since 1920: Volume II", 1997