US Air Force turns to 1920s German process that converts hydrocarbons in bid to reduce reliance on overseas oil
The US Air Force Flight Test Center at Edwards AFB in Caifornia will in September carry out three test flights of a Boeing B-52 Stratofortress with two of the aircraft's eight Pratt & Whitney TF33 engines using a synthetic jet fuel.
The fuel is a 50:50 blend of petroleum JP-8 and the synthetic JP-8, produced using the Fischer Tropsch (FT) process. The tests form part of the US Department of of Defense Assured Fuels Initiative (AFI), which began in 2001.
The aim of the AFI is to reduce US reliance on foreign oil. FT JP-8 is produced using a process developed by 1920s German researchers Franz Fischer and Hans Tropsch. It can turn coal and other hydrocarbon sources into a petroleum-like liquid fuel.
The two TF33s using the blended fuel require no changes to their combustion systems, only additional instrumentation to collect engine condition data.
"Other flights will be made in the future and they are currently in the planning stage," says the US Air Force Research Laboratory propulsion directorate turbine engine division fuels branch chief and AFI senior adviser, William Harrison.
If approved, the synthetic fuel would not require fleet-wide engine changes because, according to Harrison, pure FT fuel is much cleaner than JP-8. There is a research programme to determine if pure FT JP-8 can be used interchangeably with blended and neat petroleum fuel.
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| Two of the B-52's engines will use synthetic JP-8 in a September flight |
Extensive laboratory testing has been carried out for the past several years by the air force, army, navy and the US government's energy department as part of AFI.
Other research has included an Allison T63 helicopter engine running on neat FT as well as blends.
Additional testing of aircraft and ground hardware will take place later this year and during 2007. During the oil crisis of the 1970s, the USAF examined a number of alternative fuels, such as shale oil-based JP-4 at Wright-Patterson AFB using a North American T-39 Sabreliner.
Source: Flight International
