EG-0088-01
The Bell X-5 was built to test the feasibility of changing the sweep angle of an aircraft’s wings in flight. This had advantages from an operational and research point of view. An operational aircraft could take off with its wings fully extended, reducing its take off speed and the length of the runway needed.
Once in the air, the wings could be swept back, reducing drag and increasing the aircraft’s speed. For an experimental aircraft, the ability to vary the wing’s sweep angle would greatly expand the research possibilities. Existing swept wing experimental aircraft, such as the D-558-II, XF-92A, X-2, and X-4, could each provide aeronautical data at only a single wing angle. A variable swept wing aircraft would be equivalent to a series of such experimental aircraft, as it could change the wing angle to the desired research objectives.
Although the NACA conducted independent wind tunnel research on variable sweep wings in 1945, the X-5 originated with the Messerschmitt P.1101 experimental aircraft. This was a small jet with wings that could be adjusted on the ground to three fixed angles between 35 and 45 degrees. The P.1101 had not flown before it was captured by U.S. troops in April 1945. The aircraft was examined by Bell Aircraft engineers following its arrival in the U.S. Robert Wood, head of Bell’s design team, proposed in July 1948 that a modified and enlarged version of the P.1101 be built. Unlike the original aircraft, the proposed Bell aircraft could change its sweep angle in flight, rather than being set on the ground before takeoff. The NACA, which had continued to make studies of variable sweep aircraft, supported Bell’s proposal. This was a major reason why Air Force Headquarters approved the project on February 4, 1949…Learn more