Aviation fuel

Aviation fuel is a specialized type of petroleum-based fuel used to power aircraft. It is generally of a higher quality than fuels used in less critical applications, such as heating or road transport, and often contains additives to reduce the risk of icing or explosion due to high temperature, among other properties. Aviation fuel is a specialized type of petroleum-based fuel used to power aircraft. It is generally of a higher quality than fuels used in less critical applications, such as heating or road transport, and often contains additives to reduce the risk of icing or explosion due to high temperature, among other properties. Most current commercial airlines and military aircraft use jet fuel for maximum fuel efficiency and lowest cost. These aircraft account for the vast majority of aviation fuel refined today, which is also used in diesel aircraft engines. Other aviation fuels available for aircraft are kinds of petroleum spirit used in engines with spark plugs (e.g., piston and Wankel rotary engines). Specific energy is the important criterion in selecting an appropriate fuel to power an aircraft. Much of the weight of an aircraft goes into fuel storage to provide the range, and more weight means more fuel consumption. Aircraft have a high peak power and thus fuel demand during take-off and landing. This has so far prevented electric aircraft using electric batteries as the main propulsion energy store becoming widely commercially viable. Jet fuel is a clear to straw-colored fuel, based on either an unleaded kerosene (Jet A-1), or a naphtha-kerosene blend (Jet B). Similar to diesel fuel, it can be used in either compression ignition engines or turbine engines. Jet-A powers modern commercial airliners and is a mix of pure kerosene and burns at temperatures at or above 49 °C (120 °F). Kerosene-based fuel has a much higher flash point than gasoline-based fuel, meaning that it requires significantly higher temperature to ignite. It is a high-quality fuel; if it fails the purity and other quality tests for use on jet aircraft, it is sold to other ground-based users with less demanding requirements, such as railroad engines. Avgas (aviation gasoline) is used in spark-ignited internal-combustion engines in aircraft. Formulated for stability, safety, and predictable performance under a wide range of environments, avgas is typically used in aircraft which use reciprocating or Wankel engines. Its formulation is distinct from the motor gasoline, a.k.a petrol used in cars - which aviators refer to as mogas. Although it comes in many different grades, in general the octane rating is generally much higher than motor gasoline. Alternatives to conventional fossil-based aviation fuels, new fuels made via the biomass to liquid method (like sustainable aviation fuel) and certain straight vegetable oils can also be used. Fuels such as sustainable aviation fuel have the advantage that few or no modifications are necessary on the aircraft itself, provided that the fuel characteristics meet specifications for lubricity and density as well as adequately swelling elastomer seals in current aircraft fuel systems. Sustainable aviation fuel and blends of fossil and sustainably-sourced alternative fuels yield lower emissions of particles and GHGs. They are, however, not being used heavily, because they still face political, technological, and economic barriers, such as currently being more expensive than conventionally produced aviation fuels by a wide margin. Compressed natural gas (CNG) and liquified natural gas (LNG) are fuel feedstocks that aircraft could switch to, other than conventional fossil-oil. Turbofans for instance can be operated on a number of different fuels, and some have been made optimized for use with natural gas. Some aircraft, such as the Tupolev Tu-155, as well as the 'SUGAR Freeze' aircraft under NASA's N+4 Advanced Concept Development program (made by Boeing's Subsonic Ultra Green Aircraft Research (SUGAR) team), were designed to run on LNG. The low specific energy of natural gas even in liquid form compared to conventional fuels gives it a distinct disadvantage for flight applications.