Allison T56 / Model 501D / T701

Rolls-Royce T56

T56-A-16

The Allison T56 is a single shaft, modular design military turboprop with a 14 stage axial flow compressor driven by a four stage turbine. It was originally developed by the Allison Engine Company for the Lockheed C-130 transportentering production in 1954 but was produced under Rolls-Royce which acquired Allison in 1995. The commercial version is designated 501-D. With an unusually long and numerous production run, over 18,000 engines have been produced since 1954, logging over 200 million flying hours.

The engine evolved from Allison's previous T38 series. It was first flown in the nose of a B-17 test-bed aircraft in 1954. Originally fitted to the Lockheed C-130 Hercules, the T56 was also installed on the P-3 and E-2/C-2 aircraft, as well as civilian airliners such as the Lockheed Electra and Convair 580. A shipboard version, the 501K engine, is used to generate electrical power for all U.S. Navy cruisers and destroyers currently in commission.

In the Lockheed Martin C-130J Super Hercules which first flew in 1996, the T56 is replaced by the Rolls-Royce AE 2100, which uses dual FADECs (Full Authority Digital Engine Control) to control the engines and propellers. It drives new six-bladed scimitar propellers from Dowty Rotol.

More than 18,000 have been built.

Variants:

501-D13
(Series I) Lockheed L-188 Electra and Convair CV-580 (Replacing P & W R-2800) starting December 1957

501-D13A
(Series I) Similar to -D13

501-D13D
(Series I) Similar to -D13

501-D13H
(Series I) Similar to -D13

501-D22
(Series II) Lockheed L-100 Hercules

501-D36A
(Series II) (non-type certified)

501-D22A
(Series III)

501-D22C
(Series III) similar to -D22A

501-D22G
(Series III) similar to -D22A

501-M62
Company designation for the T701-AD-700 Turbo-shaft engine to power the Boeing-Vertol XCH-62 Heavy-lift helicopter.

T56-A-7
(Series I)

T56-A-8
(Series I)

T56-A-9
(Series I)

T56-A-9D
(Series I) Lockheed C-130A Hercules Starting December 1956 and on all Grumman E-2A Hawkeyes from 1960

T56-A-9E
(Series I) Similar to -A-9D

T56-A-10W
(Series I) with water injection

T56-A-7A
(Series II) Lockheed C-130B Hercules Starting May 1959

T56-A-7B
(Series II) Similar to -A-7A

T56-A-10WA
(Series II)

T56-A-14
(Series III) Lockheed/Kawasaki P-3/EP-3/WP-3/AP-3/CP-140 Aurora from August 1962

T56-A-15
(Series III) Lockheed C-130H Hercules from June 1974

T56-A-16
(Series III)

T56-A-425
(Series III) Grumman C-2A Greyhound from June 1974

T56-A-14+
(Series III.V) Fuel efficiency and reliability upgrade

T56-A-15+
(Series III.V)

T56-A-16+
(Series III.V)

T56-A-425+
(Series III.V) Northrop Grumman E-2 Hawkeye from August 2011

T56-A-427
(Series IV) Northrop Grumman E-2 Hawkeye upgrades from 1972

T56-A-427A
(Series IV) similar to the -A-427

T701-AD-700
(501-M62) Turbo-shaft engine for the Boeing-Vertol XCH-62 Heavy-lift helicopter.

Applications:
Lockheed Martin C-130 Hercules
Lockheed P-3 Orion
Northrop Grumman E-2 Hawkeye
Grumman C-2A Greyhound
Convair 580 and Convair 5800
Lockheed L100 Hercules
Lockheed L-188 Electra
Lockheed R7V-2 Constellation - Done for testing the model 501D for use on the L-188 Electra. Was nicknamed "Elation" during testing.
Aero Spacelines Super Guppy

Specifications:

T56 Series IV
Type: Turboprop
Length: 146.1 in (3,711 mm)
Diameter: 27 in (690 mm)
Dry weight: 1,940 lb (880 kg)
Compressor: 14 stage axial flow
Combustors: 6 cylindrical flow-through
Turbine: 4 stage
Fuel type: JP8 2412 pounds per hour
Maximum power output: 4,350 shp (3,915 kW) limited to 4,100
Turbine inlet temperature: 860°C
Power-to-weight ratio: 2.75:1 (shp/lb)