Learjet 20

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Learjet 20
250px
Description
RoleBusiness Jet
Crew2
First Flight@
Entered Service@
Number built562
ManufacturerLearjet
Dimensions
Lengthmft in
Wingspanmft in
Heightmft in
Wing areaft²
Weights
Emptykglb
Loadedkglb
Maximum takeoff weightkglb
Capacity@
Powerplant
Enginestwo Garrett TFE731-2-2B turbofan engines
Thrust@ kN (each)lbf (each)
Performance
Maximum speedkm/hmph
Operational rangekmmiles
Service ceilingmft
Rate of climbm/minft/min

Contents

History

The Model 23 has its roots in a proposed fighter aircraft for Switzerland known as the FFA P-16, designed by Hans-Luzius Studer. Although the fighter prototype crashed during Swiss Air force testing and the P-16 program was abandoned, William (Bill) Powell Lear, Sr. recognized the design's potential and established Swiss American Aviation Corporation (SAAC) to produce a passenger version as the SAAC Lear Jet 23. The company was moved to Wichita, Kansas where production was started on the first Model 23 on February 7, 1962. The first flight of the Learjet 23 took place on 7 October 1963. On October 13, 1964, the first production aircraft was delivered. With this jet a completely new market for fast and efficient business aircraft was opened. The Model 23 is considered as a model for a whole set of similar aeroplanes which remain in production. Production of the Learjet 23 stopped in 1966 after a total of 104 had been built. In 1998 there were still 39 Model 23s in use. A total of 27 have been lost or damaged beyond repair through accidents during the aircraft's lengthy career, the most recent in 2008

Versions

Learjet 23

Initial production model, 32 a/c built. Using essentially the same power plants as the Northrop F-5 Freedom Fighter supersonic fighter, the Lear 23 had astonishing performance. With two pilots and a full load of five passengers, it could climb to 40,000 feet in just over seven minutes. In one early publicity flight, a Learjet made a round trip between New York and Los Angeles in 11 hrs 35 min, including refueling stops. But there was a downside to the Lear 23's fighterlike performance: a fighterlike accident record. Lear's creation was a demanding aircraft to fly, unforgiving of pilot errors.

Learjet 24

The Model 23 was replaced by the Model 24 in 1966. This was a considerably modified development to meet FAR. Part 25 certification requirements. Upgrades included higher cabin pressurization (allowing it to higher climb altitudes), more powerful engines a new windshield, auxiliary fuel in wing tip tanks and a fire-extinguishing system for the engines. The first flight of a Learjet 24 took place on January 24, 1966. Submodels are the Learjet 24A (converted from existing Learjet 23, MTOGW 13,499 pounds (6,123 kg), certified on November 9, 1966, 81 aircraft built), the Learjet 24B (improved variant, powered by two 2,950 lbf (13.1 kN) thrust CJ610-6 turbojet engines, and 13,499 pounds (6,123 kg) MTOGW, certified December 17, 1968, 49 aircraft built), Learjet 24C (A light-weight version of the 24B, fuselage tank not fitted which would have caused a reduction in range, abandoned), Learjet 24D (similar to Learjet 24C, however by changing surface tanks range and takeoff weight were increased to 6,129 kilograms (13,510 lb), round cabin windows replaced by angular, certified July 17, 1970, a Learjet 24D/A reduced gross weight (restricted to 12,500 pounds (5,700 kg) version was also available (the 24D/A). 99 built). The Learjet 24E/F featured a new cambered wing and aerodynamic improvements to reduce stall and approach speed. The Learjet 24E is a Learjet 24C with minor changes for air taxi work while the Learjet 24F is a Learjet 24D with additional fuselage fuel tank.

Learjet 25

Powered by two General Electric CJ610-8A turbojet engines. The initial Learjet 25A was certified October 10th, 1967. followed by the Learjet 25B on September 4th, 1970. The Learjet 25C, also certified September 4th, 1970, offered increased range, while the ultimate Learjet 25, the Learjet 25D stretched the range to 2,650 km range. The Learjet 25E designation was not used, due to "Economy" implication. The Learjet 25F is a Model 25D with eight-place seating and increased fuel/range. The Learjet 25G, introduced September 23rd, 1980, modification kit features drag reduction mods and additional fuel, resulting in a 3,300 km with 4 pax. 311 a/c built.

Learjet 26

26 Proposed Model 23 with Garrett TFE731 engines. Not built but eventually evolved in the Learjet 35.

Learjet 28

Major redesign of the Learjet 25D with NASA-designed supercritical wing was fitted with Longhorn winglets and the tips - and as a consequence all fuel had to internally housed due to the deletion of the wingtip tanks. The Learjet 28 was the shorter range model, the Learjet 29 the longer range model. 5 a/c built.

Learjet 29

Longer range model of the Learjet 28. 4 a/c built.

Military operators

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Related developments

Aircraft of comparable role, configuration and era

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