βοΈ Full Specifications
| Designation | X-5 |
| Manufacturer | Bell Aircraft Corporation |
| Country | πΊπΈ United States |
| First Flight | 1951 |
| Retired | 1955 |
| Crew | 1 |
| Length | 10.16 m (33.3 ft) |
| Wingspan | 9.75 m (32 ft) |
| Height | 3.66 m (12 ft) |
| Empty Weight | 2,880 kg (6,350 lb) |
| Max Takeoff Weight | 4,536 kg (10,002 lb) |
| Max Speed (Mach) | 0.93 |
| Max Speed | 1,141 km/h (709 mph) |
| Service Ceiling | 12,700 m (41,669 ft) |
| Range | 1,190 km (739 mi) |
| Engine | 1 Γ Allison J35-A-17A turbojet |
| Thrust (each) | Dry 21.6 kN |
| Production | 2 |
π Operators
π Variants
- X-5 (50-1838) β First prototype, surviving airframe at USAF Museum
- X-5 (50-1839) β Second prototype, lost October 1953
βοΈ Armament
Overview
The Bell X-5 was the first aircraft capable of changing its wing sweep angle while in flight. Two prototypes flew between 1951 and 1955 in a research program operated jointly by Bell, the U.S. Air Force, and the National Advisory Committee for Aeronautics (NACA β predecessor of NASA). The X-5’s success directly enabled the variable-sweep designs that came later, including the F-111 Aardvark, F-14 Tomcat, B-1 Lancer, and Tu-160 Blackjack.
Design & Development
The X-5 was based on the German Messerschmitt P.1101 β an unfinished prototype captured at the end of World War II and shipped to Wright Field in 1948. The P.1101 had been designed to allow ground crews to change wing sweep manually between flights; Bell’s major contribution was to redesign the system so that the pilot could change sweep continuously from 20Β° to 60Β° while airborne.
Two airframes were built, designated 50-1838 and 50-1839. Power came from a single Allison J35-A-17A turbojet of 22 kN thrust. The aircraft was small (length 10.16 m, wingspan 9.75 m at full extension) and was strictly a research vehicle β no weapons were ever fitted.
Operational History
The first X-5 (50-1838) flew on June 20, 1951, with Bell test pilot Jean “Skip” Ziegler at the controls. The first in-flight sweep change came on July 27, 1951. Tests revealed that the aircraft suffered from poor stall characteristics at the highest sweep angles and a dangerous tendency to enter unrecoverable spins. The second X-5 (50-1839) was lost on October 14, 1953, when Air Force Captain Raymond Popson was killed after the aircraft entered an unrecoverable spin during high-sweep handling tests.
The surviving X-5 (50-1838) continued flight testing with NACA until 1955, accumulating valuable data on variable-sweep flight characteristics. It is now displayed at the National Museum of the U.S. Air Force.
Legacy
Despite its problematic handling, the X-5 conclusively proved that in-flight sweep change was a workable concept. The data it produced informed every subsequent variable-sweep program β the F-111 (first flight 1964), Mikoyan MiG-23 (1967), Tu-22M (1969), F-14 Tomcat (1970), Su-24 (1970), Panavia Tornado (1974), Rockwell B-1 Lancer (1974), and Tupolev Tu-160 (1981). The era of swing-wings lasted roughly four decades; the X-5 made all of it possible.
References
- NACA flight test reports, 1951β1955
- Bell Aircraft Corporation X-5 program documentation
- National Museum of the U.S. Air Force exhibit notes
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