The Hughes XF-11 was built to meet the same exacting specification as the Republic XR-12 Rainbow. When the USA entered the war, the USAAF lacked a purpose built reconnaissance aircraft and relied on modified fighter aircraft, such as the F-5B a reconnaissance version of the P-38 Lightning and even operated the F-8 Mosquito, licensed built by de Havilland of Canada.
In 1943, following recommendations by Colonel Elliot Roosevelt, the photographic section of the Air Technical Service drew up an exacting specification for a purpose-built reconnaissance aircraft. The requirement called for an aircraft tailored specifically for photographic reconnaissance, capable of very long range and high speed.
Howard Hughes had been fascinated with developing long-range aircraft for some time and decided that his company would respond to this requirement. Hughes had previously funded in great secrecy the Hughes D-2 high-speed long range bomber, constructed from Duramond - a plastic impregnated wood. The Hughes D-2 was first flown on 20 June 43, but performance was disappointing and the project was going no where fast - then Hughes learnt of the new requirement and decided that a modified version of the D-2 could meet the requirement.
The XF-11 had a wing span of 101ft 5in and a length of 65ft 5in and the central pod was pressurized to ensure crew comfort at high altitudes. Power was provided by two P&W R-4360-31 engines with contra-rotating propellers. The XF-11 was planned to have a ceiling over 40,000ft with a speed of over 400mph, well in excess of recce aircraft then in service. The nose area carried an impressive array of cameras which looked out through a variety of ports - a further four cameras were carried in the rear of the left boom. A crew of two was carried, a pilot and a second pilot who also acted as the navigator and camera operator. Hughes demanded absolute perfection in every detail of the prototype XF-11. Rivets were all flush, joints were smoothed and sanded to ensure that the airframe was an aerodynamic as possible. As a finish, the airframe was painted Light Grey and then given a very shiny nylon-based top coat, which was heavily waxed and polished once it had dried.
However, on 7 Jul 46, whilst on an early test flight, the right engine failed sending the propeller into reverse, and causing the XF-11 to descend in a rapid spiral. The aircraft crashed into an area of Beverly Hills and exploded. Amazingly, Hughes managed to drag himself from the wreckage, when by all logic he should have died instantly. Hughes managed to stage a remarkable quick recovery and even flew the second prototype from his private airport at Culver City of 5 Apr 47. However, by now WW2 was over and savings had to be made and despite the Cold War looming large on the horizon, both the XF-11 and the XR-12 were cancelled.
The lack of a purpose built reconnaissance aircraft capable of operating safely over the Eastern Block was to cost the USAF dear in the late 1940's and early 1950's. There is little doubt that the XF-11 could easily have been developed into a highly capable reconnaissance aircraft if the will had existed. Whether it would have been a better or more capable aircraft than the XR-12 is debateable. However, it would certainly have been a vast improvement on the various versions of the B-29 Superfortress that were pressed into service as reconnaissance aircraft because, thanks to the cancellations, nothing else was readily available.