Efforts to develop unleaded aviation-gasoline (avgas) have been boosted by Cessna's decision that, when it restarts production of piston singles in 1996, it will use engines which can be run on low-octane unleaded fuel.
New Cessna 172s and 182s will be powered by Textron Lycoming low-compression-ratio engines, able to be run on 82-octane unleaded (82UL) fuel, as well as traditional 100-octane low-lead (100LL) avgas.
Cessna, the engine manufacturer and fuel suppliers are working on development of 82UL avgas. Fuel supplier Phillips 66 Aviation says the proposed standard is for a modified motor-gasoline (mogas) that can be used in low-compression aero-engines certificated on 80/87 avgas.
The fuel will originate as mogas, but will be subject to the quality control and handling requirements used for 100LL avgas. Phillips says that the availability of 82UL will depend on market demand, noting that 125,000 aircraft in the US general-aviation fleet use low-compression engines.
Use of mogas in aero engines has increased from 380 million litres (85 million gal) in 1983, to more than 570 million litres in 1993. Lycoming, which does not approve the use of mogas in its engines, believes the US Federal Aviation Administration will approve 82UL for use in engines already modified to run on mogas.
Source: Flight International
