Learjet 35

The Learjet 35 is one of a series of American multi-role business jets and military transport aircraft manufactured by Learjet. When used by the United States Air Force it carries the designation C-21A.

The engines are mounted in nacelles on the sides of the aft fuselage. The wings are equipped with single-slotted flaps. The wingtip fuel tanks distinguish the design from other aircraft having similar functions.

History

The availability of the Garrett AiResearch TFE731 turbofan in the late 1960s led to the development of the Learjet 25 which was initially known as the 25B-GF (Garrett Fan). A testbed Learjet 25 with a TFE731 on its left side flew in May 1971, while the definitive Learjet 35 prototype first flew on August 22, 1973.

Improvements to this model and to Learjet 36 led to the 35A and 36A from 1976, with higher standard max takeoff weights. Both models remained in production until 1994.

Development of the 35 and 36 range was taken one step further with the Learjet 31, which combines the 35/36’s fuselage and powerplants with the more modern wing of the 55 (now also on the 60) and delta fins under the tail. A 31-development aircraft first flew in May 1987 and certification was awarded in August 1988.

The improved 31A and 31A/ER are later production models, the 31A/ER being an extended-range variant with a higher maximum takeoff weight and more fuel. A new interior with increased headroom was introduced in 1995. The 200th 31A was delivered in October 2000.
Learjet became a Bombardier subsidiary in 1990.

Learjet 35 Features

The Learjet 35 is known, above all, for its range. It can fly 2,056 miles nonstop. The Learjet 35 offers more than range: it has good handling characteristics, a low fuel burn, and fast cruise speeds as well.

A maximum of eight passengers can travel in the Learjet 35’s cabin. It is 12.9 feet long, 4.9 feet wide and 4.3 feet high. There are 40 cubic feet of baggage space, enough to hold about eight standard-sized suitcases.

The real strength of the Learjet 35 is its range, takeoff, and cruise capabilities. Two Honeywell TFE731-2-2B engines provide 3,500 pounds of thrust, allowing the Lear 35 to take off in 4,972 feet. Its maximum takeoff weight is pretty high as well at 18,000 pounds.

Components of these engines have been used on much higher-performing jets. Their pressure compressors were taken from the Garret 660-series engine, which is most notably used on 747s. The engine’s turbine components come from DC-10s, and the high-pressure impellers are modified versions of the ones used in the TPE 331 and T76 engines.

The Learjet 35 has a relatively long range for a private jet and can cruise at speeds as high as 451 ktas, or 424 ktas with four passengers. Fuel consumption is excellent: the 31A burns 197 gallons of fuel per hour.

The Learjet 35 has received some attention-grabbing honors since the first serial number rolled off the line.  It was selected for use as a military jet, where it now operates with the name C-21. It was the first private jet to land at Denver International Airport when their new runway opened, and it seems to be a favorite among celebrities.

Aircraft Performance Data

• Cruise (Max speed cruise, Long range cruise, Normal cruise)
• Climb (High-speed climb, Normal climb)
• Descent (Descent Normal)
• Holding (Anti-Ice On, Anti-Ice Off)
• Mass & Balance