USAF alternative fuel tests to begin on C-17

The United States Air Force burns 12 billion litres of aviation fuel a year, accounting for a whopping 52.5% of all fossil fuels burned by the American government.  It’s now taking significant steps to find a dependable source of synthetic fuel in order to reduce its own costs, and America’s reliance on petroleum imports.

On August 8, it certified a 50-50 synthetic fuel/JP8 mix for use on the B-52 Stratofortress, and now attention is being turned to the hard-working air mobility fleet, in particular the C-17.

The C-17 tests will be important because it’s a newer aircraft with newer materials and systems,” Dr. Don Erbschloe said.

“Our goal is to have a standard protocol — a methodology to establish a military standard for the fuel. (The C-17 tests) will validate the methodology we’ll use to certify other aircraft.”

By 2010, the Air Force goal is to certify all its aircraft to use the fuel blend which mixes JP-8 with fuel produced using the Fischer-Tropsch process — a process used to convert carbon-based materials into synthetic fuel.

Roger Drinnon, C-17 alternative fuel research tests to begin“.  Air Mobility Command Public Affairs, September 5th, 2007.

The downside is that an awful lot of carbon dioxide gets released during the conversion of these carbon-based materials (coal, natural gas) into the synthetic fuel.  Although AMC’s chief scientist seems optimistic that newer technologies and methods will be developed to allow the capture of the carbon emissions generated during the Fischer-Tropsch process.  Corn and vegetable matter are a write-off, because they don’t contain enough potential energy to power jet engines.

For a start, today’s most popular alternative fuel, made from corn, is not suitable for aviation. “Corn doesn’t have the BTUs for jet fuel,” [AF Special Assistant Paul] Bollinger said, referring to the British thermal unit, a measure of energy.

Also, he and other experts said, it would be impossible to grow enough corn to make more than a dent in fuel supply.

— Don Phillips, “Military looks at synthetic fuel for bombers and fighters“. International Herald Tribune, June 17th, 2007.

Still, it’s encouraging that the government’s biggest user of hydrocarbon fuels is looking for a way out.  The good news is that emissions appear to be cleaner than regular JP8.

“During the process of creating the organic soup, you don’t introduce a lot of particulates and unwanted materials like sulfur compounds,” Mr. Erbschloe said. “Indications are that (Fischer-Tropsch fuel) doesn’t leave sooty trails.”

“In (the B-52 engine) tests, the use of the alternative fuel blend was found to reduce soot emissions by 30 percent at max power and by 60 percent at idle,” said Dr. Tim Edwards, a senior chemical engineer for the Air Force Research Laboratory’s Fuels Branch. “Sulfur emissions were reduced by 50 percent. These emissions reductions are due to the very high quality of the Fischer-Tropsch fuel blend component.”

Roger Drinnon, C-17 alternative fuel research tests to begin“.  Air Mobility Command Public Affairs, September 5th, 2007.

And, of course, the less money we pump into certain oil suppliers, the less money they’ll have to spend on their radical hobbyhorses.  If the commercial aviation sector continues to be interested and involved in the development process, it has the potential to snowball into something much greater, impacting the economic and environmental dynamics of air travel.

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