Aviation Fuel
The main purpose of the aviation fuel is to deliver a uniform flow of energy under constant pressure to the engine under all operating conditions. Aviation fuel is a special type of fuel used to power the airplane and is basically petroleum based. It is of better quality than fuels used in less critical applications, such as in automobiles and factories, and these often contain special additives to diminish the risk of icing or explosion due to high temperature, among other properties.
Types of Aviation Fuel
AVGAS
Reciprocating engines burn gasoline, also known as AVGAS. It is specially formulated for use in airplane engines. Combustion releases energy in the fuel, which is converted into the mechanical motion of the engine. AVGAS of any variety is primarily a hydrocarbon compound refined from crude oil by fractional distillation. Aviation gasoline is different from the fuel, refined for use in turbine-powered plane. AVGAS is one of the most volatile fuels and is extremely flammable with a very low flash point. Turbine fuel is a kerosene-type fuel which has a much higher flash point, so it is less flammable. AVGAS is used in airplanes that use reciprocating/Wankel engines.
Plane engines must perform throughout a wide range of demanding conditions. They must be lightweight and produce significant power in a wide range of atmospheric and engine operating temperatures as well as perform all kinds of maneuvers. The aviation fuel used, must support uninterrupted combustion throughout this range and must truly burn itself out rather than explode or detonate. This ensures maximum power derivation and minimal engine wear. Over the years, AVGAS has been available in different formulas. These mostly correlate to how much energy can be produced without the fuel detonating. Larger engines with high compression rate require fuel with a greater amount of potential power production without detonation than smaller low-compression engines.
Aromatic Fuels
The aviation gasoline market is a relatively small part of the overall gasoline market. AVGAS producers are few in the whole world because of the high cost of production. In years past, when this was less the case, considerable quantities of aromatic hydrocarbons were sometimes added to increase the rich mixture performance of AVGAS. It was used mainly in high horsepower engines, such as military and transport category plane. Special hoses and seals were required for use of aromatic fuels because of low viscosity value. These additives are no longer available because of low demand and high production charges.
AVGAS Types
The existence of more than few types of fuels makes it imperative that fuel be positively identified and never introduced into a fuel system that is not designed for it. The use of dyes in fuel helps aviators monitor fuel type in many ways. The color of the fuel guarantees that it shouldn’t go into wrong fuel systems as well as it makes sure that it isn’t contaminated. 100LL AVGAS is the AVGAS most readily available and used in the United States. It is dyed blue. Some 100 octane or 100/130 fuel may still be available, but it is dyed green.
80/87 AVGAS is no longer available. It was dyed red.. A new AVGAS fuel, 82UL, has been introduced for use by this group of relatively low compression engines with a very high octane value. It is dyed purple.
115/145 AVGAS is a fuel designed for very large, high performance reciprocating engine from the World War II era. It is available only by special order from refineries, and is also dyed purple in color. The color of fuel may be referred to in older maintenance manuals. All grades of jet fuel are colorless or straw colored. This distinguishes them from AVGAS of any kind that contains dye of some color.
