Private Pilot Flight Training and Instruction Flight Training Article Library | Back To 4VFR.COM Hundred Octane Aviation Fuel Interestingly of all machines, only airplanes have their own fuel In the late 1930s light weight and compact engines were being developed with compression ratios that required fuels not subject to detonation. 100 octane began as a scientific curiosity by blending 70 octane with chemicals such as tetraethel lead and hydrogen to get the higher octane. In 1938 an alkylation process by Humble Oil greatly increased the possible production of 100 octane. Cold acid alkylation made it possible to raise 1943 production of 100 octane to 15,000,000 gallons per DAY! However, full power engines still encountered detonation. The solution was to use fuel additives that would become effective to prevent detonation at full power operations but at lower powers were adjusted to lower octane. 100/130, 91/95, and 80/87 aviation octane fuels became the norm. By mid-1940 all British fighters were converted to operate on 100/130. This change allowed manifold pressures to be raised from 42 to 54 inches. This gave every engine an effective 30% increase in power. Now, tell me, what won the Battle of Britain. Chandelle is French from montrer en chandelle, which means climb around a candle. Written by Gene Whitt Flight Training Article Library | Back To 4VFR.COM