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)
Values are derrived from a variety of categories related to the design, overall function, and historical influence of this aircraft in aviation history.
MF Power Rating (BETA)
The MF Power Rating takes into account over sixty individual factors related to this aircraft entry. The rating is out of 100 total possible points.
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