Hughes XF-11: Difference between revisions
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The first prototype, tail number 44-70155, piloted by [[Howard Hughes|Hughes]], crashed on 7 July 1946 while on its maiden flight.<ref>[http://www.check-six.com/Crash_Sites/XF-11_crash_site.htm Crash of the XF-11]</ref> An oil leak caused the right-hand propeller controls to lose their effectiveness and the rear propeller subsequently reversed its pitch, disrupting that engine's thrust, which made the aircraft yaw hard to the right.<ref name="Winchester p.223"> Winchester 2005, p. 223.</ref> Rather than feathering the propeller Hughes elected to make an emergency landing on the [[Los Angeles Country Club]]'s [[golf|golf course]], but about 300 yards short of the course, the aircraft suddenly lost altitude and clipped three houses. The third house was completely destroyed by the fire resulting from the crash and Hughes was nearly killed. <ref>[http://www.check-six.com/Crash_Sites/XF-11_crash_site.htm XF-11 Crash site]</ref> |
The first prototype, tail number 44-70155, piloted by [[Howard Hughes|Hughes]], crashed on 7 July 1946 while on its maiden flight.<ref>[http://www.check-six.com/Crash_Sites/XF-11_crash_site.htm Crash of the XF-11]</ref> An oil leak caused the right-hand propeller controls to lose their effectiveness and the rear propeller subsequently reversed its pitch, disrupting that engine's thrust, which made the aircraft yaw hard to the right.<ref name="Winchester p.223"> Winchester 2005, p. 223.</ref> Rather than feathering the propeller Hughes elected to make an emergency landing on the [[Los Angeles Country Club]]'s [[golf|golf course]], but about 300 yards short of the course, the aircraft suddenly lost altitude and clipped three houses. The third house was completely destroyed by the fire resulting from the crash and Hughes was nearly killed. <ref>[http://www.check-six.com/Crash_Sites/XF-11_crash_site.htm XF-11 Crash site]</ref> |
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The second prototype was fitted with conventional propellers and flown on 5 April 1947, after Hughes had recuperated from his injuries. This test flight was uneventful and the aircraft proved to be stable and controllable at high speed. However, it lacked low-speed stability as the ailerons were ineffective at low altitudes, and when the Air Force evaluated it against the XF-12, testing revealed the XF-11 was harder to fly and maintain, and projected to be twice as expensive to build. <ref name="Winchester p.223"/>A small production order for the XF-12 went out but the USAF chose the [[B-50 Superfortress|RB-50 Superfortress]], and Northrop [[F-15 Reporter]] instead, which had similar long-range photo-reconnaissance capability and were available at a much lower cost. |
The second prototype was fitted with conventional propellers and flown on 5 April 1947, after Hughes had recuperated from his injuries. This test flight was uneventful and the aircraft proved to be stable and controllable at high speed. However, it lacked low-speed stability as the ailerons were ineffective at low altitudes, and when the Air Force evaluated it against the XF-12, testing revealed the XF-11 was harder to fly and maintain, and projected to be twice as expensive to build. <ref name="Winchester p.223"/> A small production order for the XF-12 went out but the USAF chose the [[B-50 Superfortress|RB-50 Superfortress]], and Northrop [[F-15 Reporter]] instead, which had similar long-range photo-reconnaissance capability and were available at a much lower cost. When the United States Air Force was created as a separate service in 1948, the XF-11 was redesignated the XR-11. The surviving XR-11 prototype arrived at [[Eglin Air Force Base]] in December 1948 for operational suitability testing. <ref>Fort Walton, Florida, "''New Ship At Eglin''", Playground News, Thursday 30 December 1948, Volume 3, Number 48, page 1.</ref> |
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==Specifications (XF-11)== |
==Specifications (XF-11)== |
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Revision as of 07:35, 1 January 2010
| XF-11 | |
|---|---|
| |
| Hughes XF-11 on test flight, 1947 | |
| Role | Reconnaissance |
| Manufacturer | Hughes Aircraft |
| Designer | Howard Hughes |
| First flight | 7 July 1946 |
| Status | Cancelled due to oil leak resulting in crash |
| Primary user | U.S. Army Air Force (intended) |
| Number built | 2 |
The Hughes XF-11 was a prototype military reconnaissance aircraft, designed and flown by Howard Hughes for the United States Army Air Force. Despite promise, the XF-11 suffered a crash that nearly killed Hughes. The program never recovered from this setback.
Design and development
The aircraft was designed to meet the same requirements as the Republic XF-12. Specifications called for a fast, long ranging photo-reconnaissance aircraft. Said to be a scaled-up version of the earlier Hughes D-2, the final design was similar in general appearance to the World War II Lockheed P-38 Lightning [1]. It was a tricycle-gear, twin-engine, twin-boom all-metal monoplane with a pressurized central crew nacelle, with a much larger span and much higher aspect ratio than the P-38's wing.
The XF-11 used Pratt & Whitney R-4360-31 28-cylinder radial engines with twin four-bladed, controllable-pitch propellers at the front of each engine. Each engine had a pair of contra-rotating propellers, which can increase performance and stability, at the cost of increased mechanical complexity.
The Army originally ordered 100 of them for photo reconnaissance. The order was cancelled following the end of World War II, leaving Hughes with two prototypes.
Operational history
The first prototype, tail number 44-70155, piloted by Hughes, crashed on 7 July 1946 while on its maiden flight.[2] An oil leak caused the right-hand propeller controls to lose their effectiveness and the rear propeller subsequently reversed its pitch, disrupting that engine's thrust, which made the aircraft yaw hard to the right.[3] Rather than feathering the propeller Hughes elected to make an emergency landing on the Los Angeles Country Club's golf course, but about 300 yards short of the course, the aircraft suddenly lost altitude and clipped three houses. The third house was completely destroyed by the fire resulting from the crash and Hughes was nearly killed. [4]
The second prototype was fitted with conventional propellers and flown on 5 April 1947, after Hughes had recuperated from his injuries. This test flight was uneventful and the aircraft proved to be stable and controllable at high speed. However, it lacked low-speed stability as the ailerons were ineffective at low altitudes, and when the Air Force evaluated it against the XF-12, testing revealed the XF-11 was harder to fly and maintain, and projected to be twice as expensive to build. [3] A small production order for the XF-12 went out but the USAF chose the RB-50 Superfortress, and Northrop F-15 Reporter instead, which had similar long-range photo-reconnaissance capability and were available at a much lower cost. When the United States Air Force was created as a separate service in 1948, the XF-11 was redesignated the XR-11. The surviving XR-11 prototype arrived at Eglin Air Force Base in December 1948 for operational suitability testing. [5]
Specifications (XF-11)
General characteristics
- Crew: two, pilot and navigator/photographer
Performance
See also
Related development
Aircraft of comparable role, configuration, and era
Related lists
References
Notes
- ^ Winchester 2005, p. 222.
- ^ Crash of the XF-11
- ^ a b Winchester 2005, p. 223.
- ^ XF-11 Crash site
- ^ Fort Walton, Florida, "New Ship At Eglin", Playground News, Thursday 30 December 1948, Volume 3, Number 48, page 1.
Bibliography
- Barton, Charles. "Howard Hughes and the 10,000 ft. Split-S." Air Classics, Vol. 18, no. 8, August 1982.
- Winchester, Jim. "Hughes XF-11." Concept Aircraft: Prototypes, X-Planes and Experimental Aircraft. Kent, UK: Grange Books plc., 2005. ISBN 1-84013-309-2.