Rolls-Royce T56 Turboprop Engine

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About the Rolls-Royce T56:

The Rolls-Royce T56 is a single-shaft turboprop engine with a 14-stage axial flow compressor driven by a four-stage turbine. The gearbox has two stages of gear reduction and features a propeller brake. The gearbox is connected to the power section by a torque meter assembly. Other engine modules are the can-annular type combustor and the accessory drive housing.

The T56 military turboprop and its commercial equivalent, the 501-D, are two of the leading large turboprop engines on the market based on the number of units sold. In total the engine has accumulated in excess of 200 million flight operating hours. Since the first T56 engine entered production in 1954, more than 18,000 T56/501-D turboprop engines have been installed on a wide variety of aircraft, including the Lockheed Martin C-130A-H Hercules (4x T56), the Northrop Grumman E-2C/D Hawkeye/Advanced Hawkeye (2x T56) airborne early warning aircraft, the Lockheed P-3C Orion (4x T56) anti-submarine warfare (ASW) aircraft, and the Northrop Grumman C-2A Greyhound (2x T56) Carrier On-board Delivery (COD) aircraft.

Commercial aircraft applications for the T56 have included the Convair CV-580 and CV-5800, the Lockheed L-100 Hercules (the commercial variant of the C-130), and the Lockheed L-188 Electra.

On the newest variant of the C-130 Family of military airlift aircraft, the
C-130J Super Hercules, four Rolls-Royce AE 2100D3 turboprop engines are installed. Compared to the T56, the AE 2100 is easier to maintain and has lower operating costs + it features a FADEC (Full Authority Digital Engine Control) system.

The T56 Series 3.5 Engine Upgrade program uses proven technology and materials from other Rolls-Royce engines and will improve fuel efficiency (12% reduction), reduce maintenance costs, increase reliability and enhance performance. The upgrade allows T56 engines to operate at greatly reduced temperatures, which extends the service life of parts and improves reliability by 22%. In February 2016, Rolls-Royce delivered the first T56 Series 3.5 Engine Upgrade kits to the U.S. Air Force for installation on its C-130H transport fleet.

Sources Used: U.S. Department of Defense (DoD) and Rolls-Royce plc.

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Engine Type:

Turboprop Engine


E-2C Hawkeye; E-2D Advanced Hawkeye;
C-130 Hercules; P-3C Orion/EP-3E ARIES II;
C-2A Greyhound


In Production (E-2D)


Rolls-Royce plc

Price/Unit Cost:

T56-A-427: $2.40 million
T56-A-427A: $3.19 million

Rolls-Royce T56 Turpoprop Engine

By Joakim Kasper Oestergaard Balle /// Contact Forecast International

External Resources:

Rolls-Royce: T56 Turboprop Engine
Rolls-Royce: T56 Series 3.5 Engine Upgrade

YouTube: The Rolls-Royce T56 on YouTube

Fact Sheet: Rolls-Royce T56 Turboprop


Engine Specifications: Rolls-Royce T56-A-7/14/15/425/427/427A

Manufacturer: Rolls-Royce plc
(the T56 engine was originally produced by Allison
which was acquired by Rolls-Royce in 1995)
T56-A-7: 4,200 shp (3,133 kW)
T56-A-14: 4,600 shp (3,433 kW)
T56-A-15: 4,591 shp (3,425 kW)
T56-A-425: 4,600 shp (3,433 kW)
T56-A-427: 5,250 shp (3,920 kW)
T56-A-427A: 5,100 shp (3,806 kW)
Overall Pressure Ratio at Maximum Power:
T56-A-427/427A: 11.5
Compressor: Axial flow
Compressor Stages: 14 HP
Turbine Stages: 4 HP
Length: T-56-A-427/427A: 12 ft 2 in (3.71 m)
Diameter: T-56-A-427/427A: 27 in (68.58 cm)
Dry Weight: T-56-A-427/427A: 1,940 lbs (880 kg)
T56-A-7: C-130E Hercules
T56-A-14: P-3C Orion/EP-3E ARIES II
T56-A-15: C-130H Hercules
T56-A-425: C-2A Greyhound
T56-A-427: E-2C Hawkeye
T56-A-427A: E-2D Advanced Hawkeye
Price/Unit Cost:
T56-A-427: $2.40 million
T56-A-427A: $3.19 million
Introduced: 1954 (first T56)
First Run: 1950s
First Flight: August 23, 1954

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