The Rolls-Royce AE 2100 is a turboprop developed by Allison Engine Company, now part of Rolls-Royce North America. The engine was originally known as the GMA 2100, when Allison was a division of former corporate parent General Motors.
On July 11, 1989, Saab-Scania A.B. selected the GMA 2100 to power its new Saab 2000, a 50-seat stretch of the Saab 340 turboprop, in a US$500 million deal. In July 1990, Industri Pesawat Terbang Nusantara (IPTN) of Indonesia picked the GMA 2100 as the engine for the twin-engine N-250 regional airliner. Flight testing with a Dowty R373 propeller on a Lockheed P-3 Orion testbed aircraft began on August 23, 1990, and finished after over 50 hours of flight and ground testing.
The GMA 2100D3 became the powerplant for the Lockheed Martin C-130J Super Hercules. It made its first test flight on March 19, 1994, which was conducted by Marshall Aerospace on a Lockheed C-130K Hercules testbed leased from the Royal Air Force. Testing ended in June 1994 after 47 flight hours. The engine powered the initial flight of the C-130J aircraft on April 5, 1996. By April 1997, the D3 variant had received Federal Aviation Administration (FAA) type certification. 2,000 of the D3 variants have been delivered as of 2018.
The engine's C variant was certified on December 20, 1993. It powered the N-250 prototype's first flight on August 10, 1995, but the N-250 aircraft program was postponed indefinitely in the late 1990s due to the Asian financial crisis.
In June 1997, the AE 2100 was selected by Lockheed Martin and Alenia to power the C-27J Spartan tactical airlifter. In October 2015, Alenia announced plans to use a 5100hp uprated version of the AE 2100 as the baseline engine by 2017.
A derivative of the Allison AE 1107C-Liberty (Rolls-Royce T406) turboshaft engine, the AE 2100 shares the same high-pressure core as that engine, as does the Rolls-Royce AE 3007 turbofan. This core is capable of powering turboprops of up to . The AE 2100 is a two-shaft design, and it was the first to use dual FADECs (full authority digital engine control) to control both engine and propeller, allowing both to be adjusted with a single lever. There are four production variants of the engine: the civil AE 2100A, and the military variants which include the AE 2100D2/D2A, AE 2100D3, AE 2100J and AE 2100P.
The AE 2100 inherited the Allison T56's 14-stage axial compressor design, but the inlet and the stator for the first five stages have variable blades. The annular combustor has 16 air-blast fuel injection nozzles. The turbine that drives the compressor has two stages, with the first stage using single-crystal blades. A free power turbine with two stages drives the propeller through an inner shaft and a gearbox. The engine has replaceable steel blades and vanes, which are more reliable but heavier than titanium.
The AE 2100 engine and gearbox are rated at 6000shp, but was derated to for the Saab 2000, Lockheed Martin C-130J Super Hercules, and IPTN N-250, respectively. The engine uses six-bladed, all-composite blade Dowty propellers, including the model R381 on the Saab 2000, R414 on the ShinMaywa US-2, R384 on the IPTN N-250, and R391 on the C-130J military transport and the LM-100J civil-certified version of the C-130J. The gearbox has a reduction ratio of about 14 and a mean time before unscheduled removal (MTBUR) of over 35,000 hours.