Lycoming ALF 502


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

Variants

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:
; ALF502R-3
; ALF502L
In, Lycoming and NASA published a study describing the ALF504, a 12.5 bypass ratio engine producing of sea-level thrust at a specific fuel consumption of and a fan tip diameter of.
Lycoming announced its LF500 family of turbofans in September, starting with the LF507-1H and LF507-1F, which were certificated in October and March, respectively. 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, 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 with lean-back vanes, a 16-lobe forced exhaust mixer to reduce noise and specific fuel consumption, an advanced combustor, and a temperature margin increase of in the turbine. Lycoming introduced the 500 Series of common core engines of turboprops and turbofans in February as a derivative of the LF507 to power regional aircraft in the late 1990s. A turboprop version also was planned for the European Future Large Aircraft military transport. AlliedSignal, which took over Lycoming in October 1994, demonstration tested the common core in December; the core was capable of producing of thrust. After losing the competition to power the de Havilland Dash 8-400 regional turboprop, AlliedSignal abandoned the common core effort in July.
; Common Core engines
;YF102
;ALF 502
;LF 507