Lycoming T55

Updated on Dec 26, 2023

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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. Since the T55 was first developed, progressive increases in airflow, overall pressure ratio and turbine inlet temperature have more than tripled the power output of the engine.

Variants

LTC4A-1

1,651 eshp (1,232kW)

LTC4B-8D

2,970 shp (2,216 kW)

LTC4B-12

4,600 shp (3,432 kW)

T5508D

2,930 shp (2,186 kW):Commercial version of the LTC4-8D

AL5512

4,200 shp (3,133 kW)

T55-L-5

2,200 shp (1,641 kW)

T55-L-7

2,650 shp (1,977 kW)

T55-L-9

2,595 eshp (1,936 kW)

T55-L-11

3,750 shp ( 2,798 kW)

T55-L-712

3,750 shp ( 2,798 kW)

T55-L-714

4,110 shp (3,066 kW)

T55-L-714A

4,867 shp (3,631 kW)

T55-GA-715

6,500 shp (4,849 kW):variable vane control : under development.

Applications

Bell 309

Boeing CH-47 Chinook

Boeing Chinook (UK variants)

Boeing Model 360

Boeing RC-135- One T55 was fitted to the RC-135E derivative to provide power to the aircraft's phased array radar.

Curtiss-Wright X-19

North American YAT-28E Trojan

Piper PA-48 Enforcer

H1 Unlimited hydroplane

General characteristics

Type: Turboshaft

Length: 1,196.3 mm (47.1 inches)

Diameter: 615.9 mm (24.3 inches)

Dry weight: 377kg (831 lbs)

Components

Compressor: 7-stage axial compressor and 1-stage centrifugal compressor

Combustors: reverse flow

Turbine: 2-stage gas producer and 2-stage free power

Performance

Maximum power output: 4,867 shp (3,631 kW)

Overall pressure ratio: 9.32

Turbine inlet temperature: 815 °C (power turbine inlet temperature)

Power-to-weight ratio: (4,867 shp / 831 lbs) ~ 5.8568:1 shp/lb

References

Lycoming T55 Wikipedia

(Text) CC BY-SA