AFRL testing highly-efficient diesel aircraft engine

The Air Force Research Laboratory (AFRL) Advanced Power Technology Office has completed a ground test series on a new highly-efficiency diesel aircraft engine, the US Air Force announced on 11 August.

Designed by Engineered Propulsion Systems, the Graflight V-8 4.3L diesel engine is designed to use up to 40% less fuel than typical aircraft engines while increasing range and loiter time by up to 50%. It is liquid-cooled and capable of using either a composite or aluminium propeller.

According to the AFRL, the 'clean sheet' design engine is a potential replacement for current manned and unmanned aircraft internal combustion engines.

Using a new control unit, the engine can operate using readily available diesel, Jet-A, or JP-8 fuels, thereby reducing or eliminating the need to transport specialised fuels. This flexibility opens up the possibility of unmanned aircraft use in regions that were previously impractical.

During the ground testing, the engine was taken through a range of simulated operational flight conditions, from sea-level to 30,000ft and back, successfully generating data on performance factors such as fuel consumption, calibration, vibration and power output.

The AFRL will use this data to prepare for future flight testing, confirm the engine’s efficiency and validate engine performance for future air force users.

Capt. Randall Hodkin, the APTO Aviation Working Group lead, said: 'Since this engine requires less fuel to fly the same distance, an aircraft or unmanned air vehicle could either carry more payload or fly a longer mission. Overall, if implemented, this technology has the potential to provide the air force a significant improvement in mission flexibility.

'Often one of the greatest military logistics burdens is fuel transport. If we can reduce or eliminate the need to ship specialised fuels, we’ve then reduced the associated cost and risk.'