Continental’s IO-360-AF alternative fuel engine

At last week’s AOPA Aviation Summit, Continental Motors impressed many with the announcement of its IO-360-AF engine, an 180-hp powerplant that is a lower-compression ratio version of the company’s IO-360-ES engine.

According to John Dorman, director of business development for Flight Design, whose new four-seat C4 aircraft will use the engine, the ability of the IO-360-AF to operate on autogas as well as other aviation fuels such as 94UL is critical to Flight Design’s sales efforts in regions of the world where avgas is not available or very expensive. Dorman explains: “Our industry does not yet have all the answers or a clear and definite solution to what the post-100LL fuel picture will look like.  There are several potential solutions that are moving to the forefront, but these will vary by market, price and technical specifications. Flight Design’s rationale in selecting the IO-360-AF was to offer an engine to future C4 buyers that will provide the opportunity to be compatible with as many future alternative fuel solutions as possible.”

One of the markets targeted by Flight Design is China, home to Continental’s parent company, AVIC International Holding Company. My colleague, U-Fuel’s founder and president Michael Webb, spoke with Continental management at the recent AOPA meeting held in China. He commented on the aviation fuel situation there: “I just spoke with the president of Continental Motors today, Rhett Ross, at the first AOPA China meeting. He said they have designed all engines to run on ethanol-free, lead-free 94 octane autogas. In China, 97 octane is available at all fuel stations. Avgas 100LL is distributed by one government-owned company and costs $27.13 US per gallon, when available.”

Webb further stated: “U-Fuel will be installing our first GA fuel system at one of the 10 designated GA airports in China. The 0-200D powered Cessna Skycatcher will not be changed. It will need 94 octane minimum. Mr. Ross said they could change compression to 7:1 and burn 91 octane and would only lose 4% power. One of the charter members of AOPA China is Mr. Yu, retired chairman of China Eastern Airlines. He just returned from the U.S where he bought an LSA aircraft for personal use primarily because of fuel costs. The CAAC (China’s FAA) has just approved LSA aircraft and pilot licenses.”

Continental has not yet announced plans to add its FADEC systems, now available on its more powerful engines, to the IO-360-AF. Presumably, doing this would allow the engine to run on even lower octane unleaded fuels. By contrast, many of Continental’s past engines are covered by autogas STCs from Petersen Aviation. Todd Petersen, the company’s owner, recently commented that all engines covered under his STCs for operation on 91 AKI fuel in fact were tested with 89.5 AKI at the insistence of the FAA, which desired an additional margin of safety.

The GAfuels Blog is written by two private pilots concerned about the future availability of fuels for piston-engine aircraft: Dean Billing, Sisters, Ore., an expert on autogas and ethanol, and Kent Misegades, Cary, N.C., an aerospace engineer, aviation sales rep for U-Fuel, and president of EAA1114.


  1. says

    It is dissappointing to be looking at lowering the compression of such a beautiful engine just to go backwards as it were in fuel technology. If anything, I would like to see higher compression versions of these engines being offered. What a waste of engineering!
    I also am not impressed with FADEC for the reason that the pilot looses control of the engine operation, which with todays monitoring capability of the primary parameters of the engine condition available to him/her in the cockpit allows optimization of mixture depending on all factors, outside temperature, density altitude, power needed, EGT, CYL head temp., etc. (why not lean aggressively on a descent where almost no power is needed) , keeping the spark plugs clean and the tempereatures low. Pilot can, of course always richen the mixture at the point of go around prep, but why waste fuel and load up the plugs when descending??

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