Swift Enterprises, which is developing a biofuel alternative to 100LL, has completed an informal round of testing of its high-octane, unleaded, sustainable aviation gasoline in an unmodified World War II-era radial engine.
More than 100 gallons of Swift Enterprises‘ 100SF powered a Pratt & Whitney R-2800 Double Wasp engine during three days of testing conducted at Anderson Aeromotive Inc. in Grangeville, Idaho. Test results showed that 100SF produced a higher detonation onset threshold than 100LL, according to company officials. The engine was operated at 115-145 octane takeoff power settings and there were no indications of engine knock, officials add.
Ron Adams, performance lead at Swift Enterprises, said the tests were conducted to evaluate 100SF’s ability to meet the needs of pilots who fly critical missions using large radial engines.
“Some remote communities in Alaska and other areas of the world are inaccessible by ground transportation, and they depend on aircraft powered by large radial engines to bring essential supplies,” he said. “To date, these engines posed a significant barrier for any alternative aviation fuel because they demand high-octane gasoline to produce their design horsepower. We wanted proof that 100SF can shatter that barrier.”
The tests were conducted by FAA Airframe and Powerplant (A&P) mechanics Dave Ormond, who also holds inspection authorization, and John Lambert. Anderson Aeromotive is operated by Ray Anderson and Bob Nielsen, who have more than 70 combined years of radial engine experience.
Anderson explained why he and his colleagues agreed to test the gasoline: “The need to replace our present leaded avgas with an environmentally friendly alternative is obvious. We are happy to cooperate in this effort to continue to evaluate 100SF, and we look forward to the next round of testing.”
Adams said Norman Koerner, president of TriCap International Inc., was the catalyst needed to make the testing possible.
“Norm is an invaluable asset — an international MD-11 captain, and FAA-certificated A&P mechanic with subject-matter expertise in the field of warbirds and the engines that power them,” Adams said. “He approached us some years ago with the commitment to test 100SF and has been unrelenting in identifying, organizing and scheduling all the participants in these tests. We owe Tri-Cap International and Anderson Aeromotive a tremendous debt of thanks.”
Koerner has had a longtime interest in flying aircraft with large radial engines and knew the leaded fuel needed to operate them was under scrutiny.
“Learning that Swift Enterprises and Anderson Aeromotive shared this concern, it was natural to arrange the initial testing that has now proven that 100SF is most definitely a candidate for further testing,” he said.
100SF will undergo another, more intense and formal round of radial engine testing in 2012 as funding becomes available, company officials said.. Tri-Cap International will be the lead, but the date and location are yet to be confirmed.
“The next phase, which will include further detonation, ADI and pressure carburetor work, will pave the way for commercial operators of legacy aircraft, who burn more than 10% of the avgas used in the United States, to continue providing their essential service,” Koerner said. “Additionally, 100SF will be able to power the heritage aircraft that are indispensable in preserving the history of World War II. I think it’s the right thing to do, so let’s ‘keep ’em flying!'”
A video of the engine running on 100SF can be seen here