Lycoming T55
Lycoming LTC-4
Honeywell T55

T55-GA-714A turboshaft

The Lycoming T55, (Company designation Lycoming LTC-4), is a turboshaft engine used on American helicopters and fixed-wing aircraft (in turboprop form), since the 1950s. It was designed at the Lycoming Turbine Engine Division in Stratford, Connecticut as a scaled-up version of the smaller Lycoming T53. Both engines are now produced by Honeywell Aerospace. The T55 also serves as the core of the Lycoming ALF 502 turbofan.

Applications:
Bell 309
Boeing CH-47 Chinook
Boeing Chinook (UK variants)
Boeing Model 360
Curtiss-Wright X-19
North American YAT-28E Trojan
Piper PA-48 Enforcer
H1 Unlimited hydroplane

Specifications:
T55-L-714A
Type: Turboshaft
Length: 1,196.3 mm (47.1 inches)
Diameter: 615.9 mm (24.3 inches)
Dry weight: 377kg (831 lbs)
Compressor: 7-stage axial compressor and 1-stage centrifugal compressor
Turbine: 2-stage gas producer and 2-stage free power
Maximum power output: 4,867 shp (3,631 kW)
Overall pressure ratio: 9.32
Turbine inlet temperature: 815C (power turbine inlet temperature)
Power-to-weight ratio: (4,867 shp / 831 lbs) ~ 5.8568:1 shp/lb