The Bell X-5 was an experimental swept wing aircraft inspired by the wartime Messerschmitt P.1011.
The prototype of the P.1011 was discovered by US troops after they captured a research centre at Oberammergau in Bavaria. It was a jet powered aircraft with adjustable swept wings that could be set to 35, 40 or 45 degrees. The aircraft was complete, but its Junkers Jumo engine wasn't. The engine was taken back to Wright Field, but the Air Force didn’t have a use for it, and in 1948 it was lent to Bell.
Bell's original plan was to install a Allison J35 turbojet in the P.1011, but the aircraft was badly damaged when it arrived, and this plan was abandoned. The next plan was to build a significantly improved version of the aircraft, using the basic layout of the wartime aircraft, but late in 1948 this was rejected by the USAF Engineering Division.
Bell's next plan was to build two experimental aircraft using their own design for in-flight variable geometry. This aircraft, the Model 60, was of more interest, and on 26 July 1949 Bell was given a contract to produce two prototypes, with the first to be delivered within a year.
The project turned out to be much more complex than expected. A mockup was ready by December 1949, but the first prototype took two years to complete.
The X-5 was powered by a single 4,900lb Allison J53-A-17 turbojet engine that was carried below the main fuselage, with the intake in the nose and the exhaust pipe about two thirds of the way along the fuselage. The cockpit was close to the nose. The wings could move from 20 to 60 degrees, with the wing root moving forward or backwards on rails to ensure the aircraft remained balanced.
The aircraft made its maiden flight on 20 June 1951, with the wings at their maximum span. On the fifth flight the wings were swept back slightly, and this increased every flight until the maximum sweep was tried on the ninth flight. The aircraft was then accepted by the USAAF on 7 November 1951. The second aircraft was delivered on 9 December 1951. Both then took part in the USAAF and NACA test programme. The second aircraft was lost on 14 October 1953 after struggling to recover from a spin. The second aircraft was withdrawn on 25 October 1955 after 133rd flights. The pilot for its last flight was Neil Armstrong.
The X-5 proved to be a difficult aircraft to fly. It could easily become unstable, and had nasty stall characteristics. It wouldn't have made a good service aircraft, but it did provide plenty of valuable experimental data in the use of variable geometry wings.
Engine: Allison J53-A-17 turbojet
Span: 30ft 9 4/5in
Length: 33ft 4in
Empty Weight: 6,350lb
Loaded Weight: 9,892lb
Maximum Speed: 705mph
Range: 750 miles