Another step taken in search for alternate fuel

April 1, 2009

Teledyne Continental Motors and Hawker Beechcraft have joined forces to move the search ahead for an alternative to 100LL by testing a 94-octane “no lead” aviation gasoline in flight. A Beechcraft G36 (Garmin G1000-equipped) Bonanza flew several flights, the longest to date lasting one hour, with 94 unleaded fuel that was specially blended for aviation purposes.

Although heralded by Continental President Rhett Ross as another of his company’s impressive aviation firsts, there may still be a long road ahead in the alternative fuel search. For openers, it could take the industry most of this year to agree on accepting the fuel as a standard, and there is no word on whether 94 is the magic octane number for other engine manufacturers. If the industry did agree on the fuel tested by Continental, there could be problems getting the oil companies to manufacture a new fuel in addition to the current 100-octane low-lead fuel.

Would 94-octane work for all general aviation aircraft? Questions remain about getting the manufacturers to sign off on the fuel as well. These include whether modifications to engines will be required and whether operating methods would have to be revised, such as using lower power settings or other special operating techniques. Any transition of the entire general aviation fleet could take a decade or more.

Lycoming official Mike Kraft said Lycoming has also worked on the development of unleaded fuel starting in 1995. He praised Continental for contributing to the research on alternative fuels.

“It’s a good announcement and a good step,” Kraft said. However, there are larger issues left to be solved, he said. One is the question of whether a major fuel producer will actually offer the alternative fuel. The other is to realize that some of the more powerful engines may not be able to use it. While lead is used to boost octane, there are other benefits equally important, especially in high-performance engines.

“This is another big step in our sustainability initiative at Hawker Beechcraft and something that will delight general aviation pilots,” said Ed Petkus, Hawker Beechcraft vice president for product development and engineering. “This partnership with TCM exemplifies the leadership of our companies and our commitment to supporting the technologies necessary to find an alternative to 100LL. I am confident our customers and the entire aviation industry will benefit from our joint efforts.”

Continental began investigating unleaded fuel alternatives to 100LL in 2007. Efforts included participation in the Coordinated Research Council (CRC), analysis of various commercial fuel options and extensive fuel tests on engines in the company’s dynamometer test cells.

The flight profile tested all aspects of flight including takeoff, climb, maximum-power cruise, low-power cruise, descent, and landing. The airplane was equipped with data recording devices to provide data for post-flight analysis.

With the first flights complete, Continental will begin the certification process for several Continental engine models to allow them to operate on the new fuel.

Al Marsh

Alton K. Marsh | AOPA Pilot Senior Editor, AOPA

AOPA Pilot Senior Editor Alton Marsh has been a pilot since 1970 and has an airline transport pilot certificate and instrument and multiengine flight instructor certificates, aerobatic training, and a commercial seaplane certificate.