Despite the Allison T40 program failure, Allison continued to develop a single-turbine turboprop engine, as was the Allison T38 engine. The T56 engine was developed especially for the Lockheed C-130 Hercules transport aircraft. Over several decades, the Allison / Rolls Royce T56 engine has been built in over 18,000 units. The engine was used to power the P-3 Orion, E-2, Lockheed Electra, Convair 580 aircraft. The Allison T56 engine was used in many military and civil aircraft. It is produced so far (2016 year) They have a composite propeller with 6 composite blades.
The T56 engine is directly derived from the T38 engine. The main work on the T56 engine was completed in May 1953, reaching 3,000 hp. However, not everything was going well. In August 1953, the engine was to pass a 150-hour test of continuous operation. Already in the sixth hour, the engine exploded on the test bench. Another prototype was completed in September 1953. The lucky ones managed to solve all problems. Managed to increase the compression (9.25: 1) and raise the temperature in front of the turbine.
Written by Karol Placha Hetman