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MODERN FUELS The most common fuel worldwide is a Kerosene -based fuel classified as ''JET A-1''. JET A-1 is produced to an internationally standardized set of specifications, and has a Flash Point of 38°C and a freezing point maximum of -47°C. A version of JET A-1 known as ''JET A'' is available only in the United States . It is similar, except for its higher freezing point of -40°C. The only other jet fuel that is commonly used in civilian aviation is called ''JET B''. JET B is a fuel in the Naptha - Kerosene region that is used for its enhanced cold-weather performance. However, JET B's lighter composition makes it more dangerous to handle, and it is thus restricted only to areas where its cold-weather characteristics are absolutely necessary. Both JET A and JET B can contain a number of additives:
Militaries around the world use a different classification system of JP numbers. Some are almost identical to their civilian counterparts and differ only by the amounts of a few additives; JET A-1 is similar to JP-8 , JET B is similar to JP-4 . Other military fuels are highly specialized products and are developed for very specific applications. JP-5 fuel is fairly common, and was introduced to reduce the risk of fire on aircraft carriers. Other fuels were specific to one type of aircraft. JP-6 was developed specifically for the XB-70 Valkyrie and JP-7 for the SR-71 Blackbird . Both these fuels were engineered to have a high Flash Point to better cope with the heat and stresses of high speed supersonic flight. One aircraft-specific jet fuel still in use by the USAF is JPTS , which was developed in 1956 for the Lockheed U-2 spy plane. Jet fuels are sometimes classified as kerosene or naphtha-type. Kerosene-type fuels include Jet A, Jet A1, JP-5 and JP-8. Naphtha-type jets fuels include Jet B and JP-4. JET A Jet A is the standard jet fuel type in the U.S. since 1950's. Jet A has a fairly high flash point of min. 38°C, with an autoignition temperature of over 425°C. Jet A can be identified in trucks and storage facilities by the fuel code 1863. Jet A trucks, storage tanks and pipes that carry Jet A will be marked with a black sticker with a white "JET A" written over it, next to another black stripe. Jet A will have a clear to straw color if it is clean and free of contamination. Water is heavier than Jet A, and will collect on the bottom of a tank. Jet A storage tanks must be sumped on a regular basis to check for water contamination. It is possible for water particles to become suspended in Jet A, which can be found by performing a "Clear and Bright" test. A hazy appearance can indicate water contamination beyond the acceptable limit of 30ppm (parts per million). Jet A1 is a version of Jet A with freezing point of -47 °C instead of -40 °C. The U.S. commercial fuels are not required by law to contain antistatic additives, and generally do not contain them. HISTORY OF JET FUEL Fuel for a Piston-engine powered aircraft (usually a high- Octane Gasoline known as AvGas ) has a low Flash Point to improve its ignition characteristics. Turbine engines can operate with a wide range of fuels, and jet-aircraft engines typically use fuels with higher flash points, which are less flammable and therefore safer to transport and handle. The first jet fuels were based on Kerosene or a gasoline-kerosene mix, and most jet fuels are still kerosene-based. Military fuels '''. In addition, the low freezing point requirement limited the availability of the fuel. JP-1 was superseded by various "wide-cut" fuels, mixtures of Naphtha and kerosene. JP-2 (1945) was an experimental fuel. It turned out to have nonsatisfactory viscosity and flammability. JP-3 (1947-1951) was the second jet fuel in practical use. Its high vapor pressure resembled aviation gasoline, which at high altitudes caused vapor lock problems and fuel losses by boil off. JP-4 (1951-1995) is a kerosene-gasoline mix, used in the U.S. Air Force until 1990-1996, when it was replaced by JP-8. Its NATO code is '''F-40'''. It is also called '''avtag'''. It has lower vapor pressure, freeze point at -60 °C and flash point at about -18 °C. It is similar to commercial ''Jet B''. JP-2, JP-3, and JP-4 had a lower Flash Point than JP-1, but were accepted due to their greater availability. As noted above, the JP designations were not universal; other countries developing jet aircraft issued their own specifications, but the resulting fuels were similar. JP-5 (1952-present) was developed with a high flash point (min. 60 °C) for use aboard Aircraft Carriers where the risk from fire is particularly great. JP-5 remains the primary jet fuel for most navies. Its NATO code is '''F-44'''. It is also called '''avcat'''. Its freezing point is -46 °C. It does not contain antistatic additives. JP-6 (1956) was developed with special characteristics to meet fuel requirements for the XB-70 aircraft. When the XB-70 was cancelled, the JP-6 specification was also cancelled. JP-6 was based on kerosene. It was similar to JP-5, but with freezing point at -54 °C and better thermal stability. JPTS (1956) is a special fuel for the Lockheed U-2 aircraft. It has extreme thermal stability, low freezing point -53 °C, and flash point temperature min. 43 °C. It is specified by MIL-DTL-25524. It is still in use in the U-2 and newer TR-1 aircrafts. It is a highly refined kerosene with a CJFA-5 additive. JP-7 (published in 1970, but developed earlier) was a special fuel designed to meet the stringent requirements of the aircraft that became the SR-71 Blackbird . JP-7 is notable in that it is not a Distillate fuel but is created from special Blending Stocks in order to have very low (<3%) concentration of Aromatic Hydrocarbon s, and almost no sulfur, oxygen, and nitrogen impurities. It is specified by MIL-DTL-38219. It has low vapor pressure and high thermal oxidation stability. -based), which, among other characteristics, has a higher flashpoint and is less Carcinogenic , although it has a strong odor and an oily touch and is relatively unpleasant to handle. Its NATO code is F-34'''. It is specified by MIL-DTL-83133 and British Defence Standard 91-87. It is similar to the commercial ''Jet A1''. JP-8+100 is a version of JP-8 with an additive that increases its thermal stability by 100 °F (56 °C). The additive is a combination of a Surfactant , Metal Deactivator , and an Antioxidant . Its NATO code is '''F-37'''. Commercial fuels Commercial jet fuels had their origins in military fuels, but commercial use worldwide now greatly exceeds military use. As noted above Jet-A, similar to JP-8, is a pure kerosene, while '''Jet-B''' is a kerosene-gasoline mix similar to JP-4. SEE ALSO EXTERNAL LINKS
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