Learjet 24

The Learjet 24 is an American six to eight seat (two crew and four to six passengers) twin-engined, high speed business jet. Manufactured by Learjet as the successor to the Lear Jet 23.

Learjet 24

Learjet 24

History

The Learjet 24 was designed as an improved version of the Learjet 23, which was limited to 12,500 pounds (5,700 kg) gross weight. Engineers designed the model 24 to accept up to the full 13,500 pounds (6,100 kg) gross weight permitted by FAR-25 standards.

Other improvements introduced in the Learjet 24 included:

  • increased cabin pressurization, to allow a higher operating altitude
  • the addition of one extra window on each side of the cabin
  • more powerful engines
  • a new windshield
  • auxiliary fuel in wing tip tanks
  • a fire-extinguishing system for the engines

With these changes, the LJ24 became the first business jet to be certified under FAR-25.

The first flight of a Learjet 24 took place on January 24, 1966. From May 23 to 26, 1966, a Learjet 24 flew around the world in 50 hours, 20 minutes flying time as a demonstration of its capabilities.

Different variants were the 24A, B, C, D, E and F, with changes of takeoff weight, range, cabin and engines.

Altogether 259 Model 24s were built, and in 2001, there were still 210 Learjet 24s in use. Altogether 39 LJ24s had been lost through

Variants

Learjet 24A

Standard version. Converted from existing Learjet 23. Takeoff weight 5,902 pounds (2,677 kg). FAA certified on November 9, 1966. 81 aircraft built.

Learjet 24B

Improved variant, powered by two 2,950 lbf (13.1 kN) thrust General Electric CJ610-6 turbojet engines, and 6,129 pounds (2,780 kg) maximum take-off weight. FAA 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. The Learjet 24C project was abandoned in December 1970. Take-off weight 5,675 pounds (2,574 kg). None built.

Learjet 24D

Similar to Learjet 24C, however by changing surface tanks range and takeoff weight were increased to 6,129 pounds (2,780 kg). Round cabin windows replaced by angular. FAA certified July 17, 1970. Replaced the 24B in production.A reduced gross weight (restricted to 12,500 pounds (5,700 kg) version was also available (the 24D/A). 99 built.

Learjet 24D/A

Light-weight version with a retricted take-off weight of 5669-kg (12,500-lb),

Learjet 24E and 24F

Two new versions were announced in 1976 the 24E and 24F, they introduced a new cambered wing and aerodynamic improvements to reduce stall and approach speed (Century III wing). The 24E did not have a fuselage fuel tank for higher payload but shorter range. Some 24E models had the fuselage tank installed later to restore range. Powered by two 2,950 lbf (13.1 kN) thrust General Electric CJ610-8A turbojet engines. On April 15, 1977, the FAA approved extended ceiling to 51,000 feet (16,000 m), the highest level then achieved in civilian aviation. 29 aircraft built.

General characteristics

  • Crew: Two (pilot & co-pilot)
  • Capacity: 6 passengers
  • Length: 43 ft 3 in (13.18 m)
  • Wingspan: 35 ft 7 in (10.84 m)
  • Height: 12 ft 3 in (3.73 m)
  • Wing area: 231.8 sq ft (21.53 m²)
  • Airfoil: NACA 64A 109
  • Empty weight: 7,130 lb (3,324 kg)
  • Max. takeoff weight: 13,500 lb (6,123 kg)
  • Powerplant: 2 × General Electric CJ610-6 turbojet engines, 2,950 lbf (13.1 kN) each

Performance

  • Never exceed speed: Mach 0.86 (at max take-off weight)
  • Maximum speed: 545 mph (473 knots, 877 km/h) at 31,000 ft (9,450 m)
  • Cruise speed: 481 mph (418 knots, 774 km/h) at 45,000 ft (13,715 m)
  • Stall speed: 100 mph (87 knots, 161 km/h)
  • Range: 1,695 mi (1,472 nmi, 2,728 km) 4 passengers, max fuel, 45 min reserves
  • Service ceiling: 45,000 ft (13,715 m)
  • Rate of climb: 6,800 ft/min (34.6 m/s)
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