The U.S. Air Force's goal of acquiring 50 percent of its domestic aviation fuel via alternative fuel blends derived from domestic sources by 2016 got a boost on Friday March 18, when an F-22 Raptor was successfully flown at speeds of up to Mach 1.5 on a 50/50 fuel blend of conventional petroleum-based JP-8 (Jet Propellant 8) and biofuel derived from an inedible plant called camelina. The flight capped off a series of ground and flight tests carried out earlier in the week for the Raptor using the biofuel blend to evaluate its suitability in the F-22 weapons system.
Testing consisted of air starts, operability and performance at different speeds and altitudes. The test flight saw the F-22 Raptor perform several maneuvers, including a supercruise (a supersonic flight without using the engine's afterburner) at 40,000 feet reaching speeds of Mach 1.5.
"The F-22 flew on Friday, March 18 and performed flawlessly on the biofuel blend citing no noticeable differences from traditional JP-8," said Jeff Braun, director of the Air Force'sAlternative Fuels Certification Division.
The biofuel was derived from camelina sativa, a member of the mustard family and a distant relative to canola. It is a fast growing crop that can survive on little water and requires less fertilizer than many other crops. Studies have shown that camelina-based jet fuel reduces carbon emissions by around 80 percent. Additionally, its meal – what is left after oil has been extracted from the seed – has been approved by the USDA for livestock and poultry feed.
Camelina-derived synthetic fuel has been used to power a variety of military and commercial aircraft, including Europe's first biofuel-powered passenger flight in 2009. It falls into a class of hydroprocessed blended biofuels known as hydrotreated renewable jet fuels (HRJs) that can be derived from a variety of plant oil and animal fat feedstocks.
In February, Air Force officials certified its entire C-17 Globemaster III fleet for unrestricted flight operations using the HRJ biofuel blend. The success of the F-22 Raptor biofuel-powered flight suggests further similar certifications won't be far behind.