|National origin||United States|
|First flight||19 April 1979|
|Status||Active, not in production|
The Learjet 55 "Longhorn" is a business jet manufactured by Gates Learjet.
Development and design
The Learjet 50 series was first announced at the 1977 Paris air show with larger cabins than the existing Learjets. The series was to have three variants, the Learjet 54, 55 and 56 but only the Learjet 55 was built. The Learjet 55 was a low-wing cantilever monoplane with NASA developed winglets, the winglets gave rise to the nickname Longhorn. The aircraft has a T-tail and is powered by two Garrett TFE731 turbofans mounted each side of the rear fuselage. It has a retractable tricycle landing gear and an enclosed cabin for up to ten passengers and a cockpit for the two crew. Construction of the Learjet 55 began in April 1978 after extensive testing and work on the wing design which came, initially, from the Learjet 25. The Learjet 55 first flew on 19 April 1979. The first production aircraft were produced starting 18 March 1981. 147 Learjet 55 aircraft were delivered.
- Learjet 54
- Proposed 11-seat variant, not built.
- Learjet 55
- Production variant, 126 built.
- Learjet 55B
- 1986 - Improved version with a glass cockpit, improved take-off performance and increased range, 8 built.
- Learjet 55C
- 1987 - New rear underfuselage design, delta fins to increase stability and reduced the landing speed.
- Learjet 55C/ER
- Extended-range version of the Learjet 55C.
- Learjet 55C/LR
- Long-range version of the Learjet 55C, fitted with an extra tank, carrying an extra 259 lb (117 kg) of fuel in the tail cone.
- Learjet 56
- Proposed eight-seat version, not built.
Specifications (Learjet 55)
Data from 
- Crew: 2
- Capacity: 10
- Length: 55 ft 1 in (16.80 m)
- Wingspan: 43 ft 10 in (13.35 m)
- Height: 14 ft 8 in (4.48 m)
- Wing area: 264.5 sq ft (24.57 m2)
- Empty weight: 13,000 lb (5,897 kg)
- Max takeoff weight: 21,500 lb (9,752 kg)
- Powerplant: 2 × Garrett TFE731-3A-2B turbofan aero-engine, 3,700 lbf (16 kN) thrust each
- Maximum speed: 541 mph; 470 kn (871 km/h) at 30,000ft (9145m)
- Cruising speed: 462 mph; 402 kn (744 km/h) at 49,000ft (14935m)
- Range: 2,492 mi (2,165 nmi; 4,010 km) with four passengers and fuel reserves
- Service ceiling: 51,000 ft (15,545 m)
- Orbis 1985, p. 1935
- Simpson 1991, pp. 187-188
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