The Learjet 35A is a classic executive jet, the original in fact, and has for many years been the aspiration of pilots and passengers alike. Either way, if you’re in a Lear, you’ve made it!
We are working on several versions of this aircraft. One is a smaller EDF version, while the other will be a 2.5M twin turbine.
Keep checking in with us to see what is happening, or email if you have any questions….
Learjet 35A – Design, Development, Production and Performance
The Learjet 35A is one of the most successful and enduring business jets ever produced. Developed by Gates Learjet as an evolution of the Learjet 25, it combined the sleek, high-speed characteristics of the original Learjet family with quieter, more fuel-efficient turbofan engines and significantly improved range. Introduced in 1976, the 35A became the definitive version of the Learjet 35 series and remained in production until 1993, with more than 600 Model 35As built. It also served extensively in military roles, most notably as the C-21A with the United States Air Force.
Origins
The Learjet lineage began with Bill Lear’s Learjet 23, which first flew in 1963 and established the light business jet market. While the early 20-series Learjets delivered exceptional speed, they were powered by turbojet engines that were relatively noisy and fuel-hungry.
To improve efficiency and range, Gates Learjet began developing a stretched derivative powered by modern turbofan engines. The objectives were to:
- reduce fuel consumption
- increase range
- lower cabin noise
- improve take-off performance
- retain the Learjet’s high-speed capability
- provide seating for up to eight passengers
The result was the Model 35, which first flew on 22 August 1973 and was certified by the FAA in July 1974.
Development
The Model 35 represented a significant redesign rather than a simple engine upgrade.
Major changes included:
- fuselage lengthened by 13 in (33 cm)
- installation of Garrett TFE731 turbofan engines
- revised engine nacelles
- increased fuel capacity
- redesigned systems
- improved environmental control system
In 1976, Gates Learjet introduced the 35A, incorporating upgraded TFE731-2-2B engines, a higher maximum take-off weight, and additional fuel, which substantially extended the aircraft’s range. The 35A quickly replaced the original Model 35 in production.
Design Philosophy
The Learjet 35A was designed around several principles:
- maximum cruise speed
- long-range capability
- economical operation
- rapid climb to the flight levels
- excellent dispatch reliability
- comfortable executive transport
Unlike many later business jets, the Learjet retained relatively small external dimensions, prioritising aerodynamic efficiency and performance over cabin volume.
Airframe Design
Wing
The Learjet 35A uses the classic Learjet low-mounted swept cantilever wing.
Key features include:
- 13° leading-edge sweep
- integral wingtip fuel tanks
- single-slotted trailing-edge flaps
- hydraulically operated spoilers
- high-strength aluminium construction
The distinctive wingtip tanks are not merely auxiliary tanks—they form an integral part of the wing structure, reducing wing bending loads while increasing fuel capacity and range. This became a defining feature of the early Learjet family.
Fuselage
The fuselage is an all-metal semi-monocoque structure with:
- circular pressure cabin
- rear baggage compartment
- integral nose baggage bay
- pressure bulkheads fore and aft
- large passenger entry door
Typical executive layouts accommodate:
- two pilots
- six to eight passengers
The cabin was optimised for business travel rather than standing room, offering club seating, folding work tables and an enclosed lavatory in many configurations.
Cockpit
The 35A was equipped with a conventional dual-pilot cockpit.
Original avionics typically included:
- Collins navigation and communication radios
- weather radar
- flight director
- autopilot
- DME
- ADF
- transponders
Many aircraft have since been upgraded with:
- EFIS displays
- Garmin or Collins FMS
- GPS/RNAV capability
- ADS-B
- TCAS
- enhanced weather radar
- digital engine monitoring
These upgrades have allowed many aircraft to remain compliant with modern airspace requirements.
Landing Gear
The aircraft employs a hydraulically retractable tricycle landing gear.
Features include:
- dual-wheel main landing gear
- hydraulically actuated gear
- anti-skid braking
- steerable nosewheel
The relatively narrow-track undercarriage contributed to the aircraft’s sleek aerodynamic profile while maintaining good runway performance.
Powerplant
The Learjet 35A is powered by two:
Garrett (later Honeywell) TFE731-2-2B turbofan engines.
Each engine produces:
- 3,500 lbf (15.6 kN) of thrust
Compared with the turbojets used on earlier Learjets, these engines provided:
- lower fuel consumption
- reduced noise
- greater reliability
- longer engine life
- improved climb performance
- increased range
The engines are mounted on pylons attached to the rear fuselage, leaving the wing aerodynamically clean.
Aerodynamic Design
Several features contributed to the aircraft’s outstanding performance:
- highly swept wing
- area-ruled fuselage
- wingtip fuel tanks
- T-tail
- rear-mounted engines
- clean low-drag airframe
The Learjet’s relatively high wing loading produced a smooth ride at altitude but required higher approach and landing speeds than many competing business jets.
Structural Design
Construction consists primarily of:
- aluminium alloy semi-monocoque fuselage
- machined wing spars
- fail-safe structural design
- hydraulically powered flight controls
- pressurised cabin structure
The airframe was certified for repeated high-altitude pressurisation cycles and high-speed operation.
Production
Manufacturer
- Gates Learjet Corporation
Production location
- Wichita, Kansas, USA
Production timeline:
- Model 35: 1974–1976
- Model 35A: 1976–1993
Production totals:
- 64 Model 35 aircraft
- More than 600 Learjet 35A aircraft
The Learjet 35A became the highest-production Learjet model up to that time.
Military Service
The United States Air Force selected the Learjet 35A as the:
C-21A
The USAF acquired 80 aircraft for:
- VIP transport
- medical evacuation
- cargo transport
- liaison duties
Other military operators included several NATO air forces and government agencies worldwide.
Specifications (Learjet 35A)
| Item | Specification |
|---|---|
| Crew | 2 |
| Passengers | Up to 8 |
| Length | 48 ft 8 in (14.83 m) |
| Wingspan | 39 ft 6 in (12.04 m) |
| Height | 12 ft 3 in (3.73 m) |
| Wing Area | 253 sq ft (23.5 m²) |
| Empty Weight | 9,110 lb (4,132 kg) |
| Maximum Take-off Weight | 18,000 lb (8,165 kg) |
| Engines | 2 × Honeywell (Garrett) TFE731-2-2B |
| Thrust | 3,500 lbf each |
| Fuel Capacity | 931 US gal (3,524 L) |
Performance
| Performance | Value |
|---|---|
| Maximum Cruise Speed | 464 kt (859 km/h; 534 mph) |
| Long-range Cruise | 418 kt (774 km/h) |
| Maximum Operating Mach | Mach 0.81 |
| Initial Rate of Climb | 5,100 ft/min (1,554 m/min) |
| Service Ceiling | 45,000 ft (13,716 m) |
| Typical Operating Ceiling | 43,000–45,000 ft |
| Maximum Range | 2,775 NM (5,139 km) with four passengers |
| Take-off Distance | Approximately 4,790 ft (1,460 m) |
| Landing Distance | Approximately 2,660 ft (811 m) |
Flying Characteristics
The Learjet 35A is renowned for:
- exceptionally rapid climb performance
- high cruise speed
- precise, responsive controls
- excellent high-altitude efficiency
- stable instrument-flight characteristics
Pilots transitioning to the type note that it has:
- relatively high approach speeds
- higher wing loading than many competitors
- crisp control response
- excellent handling in the flight levels
Its ability to climb directly into the mid-40,000-foot range and maintain cruise speeds above 450 knots made it one of the fastest light business jets of its era.
Operational Roles
Beyond executive transport, the Learjet 35A has been widely employed in specialised missions, including:
- aeromedical evacuation
- military liaison transport
- flight inspection
- electronic warfare training
- target towing
- calibration flights
- research and atmospheric sampling
Its combination of speed, range and relatively low operating costs has made it particularly well suited to air ambulance operations in countries such as Australia, where several operators have used the type for long-range medical transport.
Legacy
The Learjet 35A represents the culmination of Bill Lear’s original light business jet concept. By replacing turbojets with efficient turbofans while retaining the sleek aerodynamics that made earlier Learjets famous, the aircraft achieved an outstanding balance of speed, range and operating economy. Its service with corporate operators, governments and military organisations—including the USAF’s C-21A—demonstrated its versatility and durability. More than five decades after the first Model 35 flew, many Learjet 35As remain in active service worldwide, reflecting the enduring quality of their design and engineering.