US researchers claim to have come up with a renewable replacement for leaded avgas 18 months ahead of the final US ban on the general aviation fuel.
Researchers from Swift Enterprises, based at Purdue University in West Lafayette, Indiana, have presented "SwiftFuel" to the Coordinating Research Council of ASTM International, the aviation fuel standards setting body.
Fuel characteristics feature zero sulphur emissions and a much lower freezing point, while offering a 15% range boost together with a 50% drop in manufacturing costs, according to Swift.
The company has also tested a drop-in variant for Jet A, although its commercial deployment is beyond the 18-month industrialisation planned for the 100-octane low-lead (100LL) avgas replacement.
The USA has banned 100LL, but it is still sold under an exemption that runs out in 2011.
Swift's exact chemical process is protected information, says research director John Rusek, but one key is that fuel is not oxygenated like ethanol and other fuels. "You can't use oxygenates as fuels. It just doesn't work. The energy is not there," he says.
As with other processes, the raw material can be anything that can be converted into sugars. "It's the components of biomass that are the most important, and that's where a lot of people miss the point," he says.
Swift's innovations are in the second stage of the conversion process, and could easily be adapted from existing ethanol facilities, he says. "America has already invested in the infrastructure - why not use it?" asks Rusek.
Swift is looking for funding to build a demonstration plant at Lafayette airport capable of producing 760 litres (200USgal) a day next year, and in 18 months it hopes to open a 7,600 litres a day pilot plant at Delphi airport, also in Indiana.