The US Air Force has extended its experiments with green technology by successfully flying an F-22 Raptor at supersonic speeds using half parts of alternative fuel blend and standard jet fuel.
The fighter jet was put through its paces 40,000 feet above the Edwards Air Force Base last week, travelling at one and a half times the speed of sound while powered by a blend of conventional petroleum-based JP-8 and alternative fuel derived from camelina, a weed-like plant not used for food. The alternative fuel is in a class of liquids known as hydrotreated renewable jet fuels (HRJs), which can be derived from a variety of plant oil and animal fat feedstocks.
The US Air Force wanted to test the performance of the alternative fuel at different speeds and altitudes, as well as ascertain its operability in manoeuvres such as air starts. “The F-22 performed flawlessly on the biofuel blend, citing no noticeable differences from traditional JP-8,” said Jeff Braun, director of the Alternative Fuels Certification Division at Wright-Patterson Air Force Base.
The results pave the way for alternative fuels to be rolled out across more of the US fleet, as the US Air Force looks to meet its target of using 50 per cent alternative fuels by 2016 – a goal adopted in response to concerns over the security of its fuel supply.
The US Air Force also trialled an alternative fuel powered A-10C Thunderbolt II last year and certified its C-17 Globemaster III carrier planes to fly with HRJ blends in February.
