USAF Raptor in Biofuel Supercruise Flight

A biofuel blend has helped power the US military’s most advanced combat aircraft to Mach 1.5, paving the way for the USAF to fully embrace alternative fuels over the next few years.

This most recent USAF biofuel test involved a Boeing F-22 Raptor and it occurred on 18 March 2011. During the flight, the Raptor was put through its paces to assess the performance of the fuel at different airspeeds and altitudes.

The fuel itself was made up of 50 per cent biofuel – which was made from a plant known as camelina – and 50 per cent regular aircraft jet fuel.

The 18 March flight was the conclusion to a whole series of Raptor biofuel trials carried out both on the ground and in the air and, during it, the stealth air superiority fighter carried out a supercruise at a height of 40,000 feet. It was during this supercruise that the Mach 1.5 figure was achieved.

Raptor Biofuel Supercruise Flight

‘Supercruise’ refers to the Raptor’s ability to surpass Mach 1 without engaging the afterburners. While the Raptor biofuel supercruise flight peaked at Mach 1.5, on conventional fuel, the aircraft can do the same at up to Mach 1.7 for sustained periods, although it’s a feature that quickly eats up the fuel.

“The F-22 flew on Friday, March 18 and performed flawlessly on the biofuel blend citing no noticeable differences from traditional JP-8 [jet fuel]”, USAF Alternative Fuels Certification Division Director, Jeff Braun, explained.

Previous research into camelina biofuels has demonstrated their ability to lower CO2 emissions associated with traditional fuels by approximately 90 per cent. The process through which it’s made has additional benefits, too: the by-products can be drawn on to feed poultry and cattle.

USAF Biofuel Flight Tests

This was the latest in a ongoing programme of USAF biofuel flight tests that have involved transport aircraft like the C-17 Globemaster III and ground attack aircraft such as the A-10 Thunderbolt II.

It was an A-10 that made history just under 12 months ago by carrying out the first ever 100 per cent biofuel-powered flight. The entire USAF C-17 fleet, meanwhile, is now certified to fly on biofuel blends.

The USAF’s short-term biofuels goal is to have them in use by half its overall fleet by 2016.

Raptor image courtesy USAF

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