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)