MANUFACTURER(S): Hughes Aircraft - USA
OPERATORS: United States (cancelled)
LENGTH: 65.42 feet (19.94 meters)
WIDTH: 101.35 feet (30.89 meters)
HEIGHT: 23.16 feet (7.06 meters)
WEIGHT (EMPTY): 37,038 pounds (16,800 kilograms)
WEIGHT (MTOW): 58,202 pounds (26,400 kilograms)
ENGINE: 2 x Pratt & Whitney R-4360-31 radial piston engines developing 3,000 horsepower each.
SPEED (MAX): 447 miles-per-hour (720 kilometers-per-hour; 389 knots)
RANGE: 4,971 miles (8,000 kilometers; 4,320 nautical miles)
CEILING: 44,012 feet (13,415 meters; 8.34 miles)
Detailing the development and operational history of the Hughes XR-11 / XF-11 Long-Range Photographic Reconnaissance Aircraft Prototype.
Entry last updated on 6/28/2018.
Authored by Staff Writer. Content ©www.MilitaryFactory.com.
Though only achieving prototype form, the XF-11 was one of the darling designs of famed American aviator Howard Hughes. Looking very much like an oversized Lockheed P-38, the twin-boom XF-11 was designed to fulfill a United States military requirement for a long-range photographic reconnaissance fighter. The project progressed with great potential until a disastrous crash of Prototype 1 in the suburbs of Beverly Hills (nearly taking the life of Hughes himself) effectively caused the cancellation of the entire project. The XF-11 would face off with Republic's offering of the XF-12 "Rainbow" only to see neither design chosen at project's end.
The XF-11 was of a traditional twin-boom design, popularized in other forms such as the Northrop P-61 Black Widow and the aforementioned Lockheed P-38 Lightning. The first of two prototypes featured contra-rotating propeller systems on each engine, offering up a great deal of power and performance potential at the cost of increased maintenance and production times. The X-11 featured a powered tricycle landing gear system which proved successful in other designs during the Second world War. The fuselage was constructed of all metal with a two-man crew - the pilot and a radio operator - in a center-fuselage nacelle with complete cabin pressurization for high-altitude capability. Pratt & Whitney brand engines were selected to power the design and these powerplants would turn two four-bladed propeller systems with variable pitch settings. With the Beverly Hills crash blamed on engine failure, the second XF-11 prototype was engineered with traditional non-contra-rotating propeller blade systems.
By all respects, the XF-11 performed admirably well considering the dramatic series of setbacks to the project. Stability and control at high speeds was especially noteworthy though exception was made to the low-altitude stability and performance the system encouraged. A complicated aircraft to fly when compared to others of this type, the XF-11 was nonetheless a capable design in most respects.
Pitted against the Republic XF-12, the XF-11 was deemed as too costly to maintain and produce along with the complications inherent in the system's design. Even with the XF-12 having an edge, the United States Air Force ultimately went with the Boeing produced RB-50 reconnaissance aircraft, citing its respectable range and reconnaissance capabilities equal to that of either XF offering with a lesser price tag.
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General Assessment (BETA)
Rating: 22 (of 100)
The rating is an internal assessment derived from 60 total factors pertaining to this aircraft.
Relative Maximum Speed Rating
This entry's maximum listed speed (447mph).
Graph average of 375 miles-per-hour.
Graph showcases the Hughes XR-11 / XF-11's operational range (on internal fuel) when compared to distances between major cities.
Useful in showcasing the era cross-over of particular aircraft/aerospace designs.
Unit Production Comparison
Comm. Market HI*: 44,000 units
Military Market HI**: 36,183 units