Lycoming ALF 502

  (Redirected from Honeywell LF 507)

The Lycoming ALF 502/LF 507 (now Honeywell) is a geared turbofan engine produced by Lycoming Engines, AlliedSignal, and then Honeywell Aerospace.

ALF 502/LF 507
ALF 502 removed from a Bombardier Challenger 600-1A11
Type Geared turbofan
National origin United States
Manufacturer Lycoming Engines
Honeywell Aerospace
First run 1980
Major applications Bombardier Challenger 600
British Aerospace 146
Northrop YA-9
Developed from Lycoming T55
The YF102-LD-100 was tested on an AJ Savage in the early 1970s.

The original YF102 was developed at the Stratford Army Engine Plant in Connecticut, by adding a fan to the Lycoming T55 engine, which was used as the gas generator.[1] Six engines were built for the Northrop YA-9 prototype ground-attack aircraft. These engines were later reused in the C-8A Quiet Short-Haul Research Aircraft (QSRA).

The ALF 502 was certified in 1980 and used on the British Aerospace 146 and Bombardier Challenger 600. The derated FADEC-equipped LF 507 was used on the Avro RJ update of the BAe 146.


Honeywell ALF 502 on an early Challenger 600

The ALF502 is a high bypass turbofan with geared fan, axial-centrifugal flow high pressure compressor, reverse flow annular combustor, two-stage high pressure turbine, two-stage low pressure turbine:[2]

ALF502R-3 (single-stage LP compressor)
  • ALF502R-4: R-3 with higher thrust
  • ALF502R-5: R-4 with improved first-stage and second-stage turbine nozzle assemblies
  • ALF502R-3A: R-3 with gas producer turbine improvements, but operated at higher thrust
ALF502L (two-stage LP compressor)
  • ALF502L-2: L with fan blade modification for increased altitude performance
  • ALF502L-3: L-2 with turbine improvements and automatic power reserve features
  • ALF502L-2A: L-2 with gas producer turbine improvements and automatic power reserve features
  • ALF502L-2C: L-2A without automatic power reserve
  • ALF502R-6: L-2C with R-5 accessory gearbox
  • LF507-1H: R-6 with lower, flat-rated thrust
  • LF507-1F: 507-1H with a single-channel FADEC with hydromechanical backup

Proposed variantsEdit

In 1972, Lycoming and NASA published a study describing the ALF504, a 12.5 bypass ratio engine producing 8,370 lbf (3,800 kgf; 37.2 kN) of sea-level thrust at a specific fuel consumption of 0.302 lb/(lbf⋅h) (8.6 g/(kN⋅s)) and a fan tip diameter of 48.0 in (1,220 mm).[3]

Lycoming announced its LF500 family of turbofans in September 1988, starting with the LF507-1H and LF507-1F, which were certificated in October 1991 and March 1992, respectively.[1]:198 In June 1992, the company outlined improvements to the LF500 family's core, which included a wide-chord fan to move more air, uprated fan gearbox, three-stage power turbine (an increase from two stages), more lighter-weight composite materials, increased diameter in the first three stages of the axial compressor to increase airflow by 17 percent, an improved impeller (centrifugal compressor) with lean-back vanes, a 16-lobe forced exhaust mixer to reduce noise and specific fuel consumption (SFC), an advanced combustor, and a temperature margin increase of 248 °F (120 °C) in the turbine.[4] Lycoming introduced the 500 Series of common core engines of turboprops and turbofans in February 1994 as a derivative of the LF507 to power regional aircraft in the late 1990s.[1]:198, 199, 200 A turboprop version also was planned for the European Future Large Aircraft military transport (which would eventually become the Airbus A400M). AlliedSignal, which took over Lycoming in October 1994,[5] demonstration tested the common core in December; the core was capable of producing 20,000 lbf (89 kN) of thrust.[6] After losing the competition to power the de Havilland Dash 8-400 regional turboprop, AlliedSignal abandoned the common core effort in July 1995.[7]

Common Core engines (LF500 family/Lycoming 500 Series/AlliedSignal AS800)
  • LF508B2: A 7,900 lbf thrust (35 kN) engine offered for the quad-turbofan powered, 120-seat British Aerospace Regional JetLiner (formerly BAe 146) in 1992[4]
  • LF509: A 9,000 lbf thrust (40 kN) turbofan engine for the Avro RJ100[8]
  • LF511D: An 11,000 lbf thrust (49 kN) turbofan with a 43 in diameter (1.09 m) wide-chord fan, a three-stage power turbine, and a three-stage low-pressure booster compressor[4]
  • LF512 / LF514: Additional turbofan engines of 12,000–14,000 lbf (53–62 kN) thrust, possibly for Avro's proposed 120-seat RJX twin airliner or for a stretched version of the 50-seat Canadair Regional Jet[8]
  • LF518: An 18,000 lbf (80 kN) turbofan variant.[9]
  • LP512: Turboprop engines targeted for the de Havilland Dash 8-400 and the proposed ATR 82, having an initial power output of 7,500 shp (5,600 kW) but with uprate capability to 11,000 shp (8,200 kW)[1]:200


Honeywell LF 507s on an Avro RJ
ALF 502
LF 507


Type Certificate Data Sheet[2]
Variant ALF502R-3 ALF502R-4/5/3A ALF502L/L-2/L-3/L-2A/L-2C/R-6 LF507-1H/1F
Configuration High bypass, geared fan
Fan diameter 40.25 in (1,022 mm)[10]
Gear ratio 2.3:1[11]
Bypass ratio 5.7:1
Compressor 1 LP, 7-stage axial[10] + centrifugal HP 2 LP, 7-stage axial[10] + centrifugal HP
Combustor Reverse flow annular
Turbine Two-stage HP, two-stage LP
Takeoff thrust 6,700 lbf (30 kN) 6,970 lbf (31.0 kN) 7,500 lbf (33 kN) 7,000 lbf (31 kN)
Length 63.66 in (1,617 mm) 65.57 in (1,665 mm)
Height 55.5 in (1,410 mm) 54.5 in (1,380 mm)
Width 47.8 in (1,210 mm) 48.6 in (1,230 mm)
Weight [a] 1,336 lb (606 kg) 1,375 lb (624 kg) (1F: 1,385 lb (628 kg))
LP rpm 7,184 - 7,374
HP rpm 19,280 - 19,760
TSFC 0.406 lb/lbf/h (41.4 kg/kN/h)[10]
Thrust/weight 5.01 5.22 5.45 5.09

See alsoEdit

Related development

Comparable engines

Geared turbofans

Related lists


  1. ^ includes essential engine accessories but excludes starter, hydraulic pump, integrated drive generator and exhaust nozzle


  1. ^ a b c d Leyes, Richard A., II; Fleming, William A. (1999). The history of North American small gas turbine aircraft engines. Reston, VA: National Air and Space Museum and American Institute of Aeronautics and Astronautics (AIAA). ISBN 1-56347-332-1. OCLC 247550535.
  2. ^ a b "Type certificate data sheet E6NE" (PDF) (15th ed.). Department of Transportation, Federal Aviation Administration (FAA). June 7, 2002. Lay summary.
  3. ^ Rauch, Dale (July 1972). Design study of an air pump and integral lift engine ALF-504 using the Lycoming 502 core (Report). National Aeronautics and Space Administration (NASA). hdl:2060/19730004744. Lay summary.
  4. ^ a b c Warwick, Graham (June 17, 1992). "Lycoming outlines LF500 power increase". Flight International. Vol. 141 no. 4323. p. 8. ISSN 0015-3710 – via Gale Research.
  5. ^ Kandebo, Stanley (November 7, 1994). "AlliedSignal completes Lycoming acquisition". Aviation Week & Space Technology. Vol. 141 no. 19. p. 35. ISSN 0005-2175.
  6. ^ "AlliedSignal runs demo test on former Lycoming 'Common Core' engine". Commuter Regional Airline News. Vol. 12 no. 50. December 26, 1994. pp. 6+. ISSN 1040-5402 – via Gale Research.
  7. ^ "AlliedSignal plans turbine closure". FlightGlobal. July 11, 1995. Retrieved July 16, 2020.
  8. ^ a b "Textron Lycoming studies 9,000 lb-thrust LF509 for 'developed' RJ100". Commuter Regional Airline News. Vol. 12 no. 28. July 18, 1994. p. 2. ISSN 1040-5402 – via Gale Research.
  9. ^ Sweetman, Bill (October 1994). "New power for regionals". Finance, markets & industry. Interavia. Vol. 49 no. 583. Minneapolis, Minnesota, U.S.A. pp. 16–18. ISSN 1423-3215. OCLC 199793280 – via EBSCOhost.
  10. ^ a b c d "ALF 502 turbofan engine". Honeywell Aerospace. November 29, 2010. Archived from the original on March 5, 2012.
  11. ^ Warwick, Graham (25 August 1993). "Engine for change". Flight International. Vol. 144 no. 4384. pp. 39+. ISSN 0015-3710 – via Gale Research.

External linksEdit