AvGas

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AvGas
other names

Aviation gasoline, aviation fuel

Trade names

AvGas 80, 82 UL, 91, 100 LL, 100

Brief description Aircraft petrol
origin

fossil

properties
Physical state liquid
density

0.73-0.78 kg / L (15 ° C)

calorific value

> 43.5 MJ / kg

Octane number
  • AvGas 100 LL: 100 MON
Melting range <-58 ° C
Boiling range

~ 30-170 ° C

safety instructions
GHS labeling of hazardous substances
02 - Highly / extremely flammable 07 - Warning 08 - Dangerous to health 09 - Dangerous for the environment

danger

H and P phrases H: 224-304-315-302-312-332-361-336-411
P: 210-260-280-301 + 310-331
As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions .

AvGas , short for Av iation Gas oline, is the technical term for aviation fuel. Other or similar spellings are: avgas , AVGAS or Avgas . In contrast to MoGas , it is designed for use at greater heights. Six types with different lead or unleaded are currently available (see standard ASTM D 910, Def Stan 91-90 / 2 (MIL), ASTM D 6227). AvGas is only by aircraft with a petrol engine or rotary engine used. Turbine-driven aircraft require as fuel kerosine ( JP-1 , or Jet A-1 ), planes with diesel engines require as fuel diesel .

designation

Aviation fuel containing lead, bottled on February 15, 2013

The individual AvGas grades are characterized by the so-called Lean Rating (see below). For some types, the addition LL ( L ow L ead = low lead) or UL ( U n L eaded = lead-free) is added. AvGas 100 LL is a variety that (casually) has an (engine) octane number (MOZ) of 100 and - compared to the AvGas 100 variety - has a lower lead content. In the past, the “octane number” of the so-called supercharge rating (see below) was also listed in the brand name, for example AvGas 100/130. In order to avoid mistakes in handling and misunderstandings, only the lean rating is used to characterize varieties.

Specifications

Lean Rating / MOZ (ASTM D 2700): The Lean Rating (LR, Lean = lean mixture) is a method developed by the US Army Air Corps (ASTM D 614) to characterize the knocking behavior of various AvGas types. The method is intended to describe the behavior of the fuel at a relatively low load on the engine. The procedure was so similar to the engine octane rating (MOZ) that in 1969 a conversion table (MOZ → Lean Rating) was included in the ASTM 2700 standard and the Lean Rating is only a value calculated (from the MOZ). In the 75–100 MOZ range, the two numbers hardly differ. From 100 MOZ the deviations are not insignificant (MOZ = 110 → LR = 128). Furthermore, the LR is referred to as a performance number (PN) from a value of 100.

Supercharge Rating (ASTM D 909): During World War II, the British developed a method to characterize the knocking properties of various AvGas grades when the engine is under high load (starting phase, rich mixture). In this case - in simplified form - the mechanical performance of the modified CFR engine made possible by the test fuel is compared with the mechanical performance of a reference fuel (isooctane / n-heptane mixture). The knock behavior is kept at the same - low - level with the help of a knock sensor for the test fuel and the reference fuel. If the test fuel enables the same performance as the reference fuel, its octane number (according to the "Supercharge Rating" method, SR) is defined with the isooctane content of the reference mixture. Of course, this is only possible with octane numbers below 100. Over 100, the reference fuel consists of a mixture of isooctane with tetraethyl lead (TEL). ASTM D 909 provides a table to convert the TEL content into a so-called Performance Number (PN). Under certain circumstances, there are then two PNs - one characterizing the lean rating and a second one for the supercharge rating. The SR cannot be compared with the research octane number (RON).

RON (ASTM D 2699): The “Research Octane Number” does not play a role in the technical characterization of AvGas. Surprisingly, however, it is used for the tax exemption of leaded, commercially used aviation fuel ( Section 27 EnergieStG: ... whose research octane number does not fall below 100.). AvGas 100 (1.12 g-Pb / L) and 100 LL (0.56 g-Pb / L) would then be tax-exempt for commercial use, AvGas 80 (0.14 g-Pb / L) definitely not for AvGas 91 (0.56 g-Pb / L) would be at least doubtful (unleaded AvGas 82 UL is not subject to the tax exemption anyway).

Blue AvGas
AvGas
  colour lead ON ON performance T10 FBP DVPE * FRP sulfur
    g / L lean (min) rich (min) Number / rich (min) (Max) (Max) kPa ° C (max) ppm (max)
AvGas 80 red 0.14 80 87 - 75 170 38-49 -58 500
AvGas UL 82 purple 0.00 82 - - 70 225 38-62 -58 500
AvGas 91 brown 0.56 91 96 - 75 170 38-49 -58 500
AvGas UL 91 colorless 0.00 91 96 - 75 170 38-49 -58 500
AvGas 100 LL blue 0.56 100 - 130 75 170 38-49 -58 500
AvGas 100 green 1.12 (MIL: 0.85) 100 - 130 75 170 38-49 -58 500
  • DVPE: Dry Vapor Pressure Equivalent (vapor pressure at 38 ° C)

use

AvGas is used today in US American ( e.g. Lycoming and Continental Motors ) and Russian aviation gasoline engines as well as for Wankel aviation engines . Some need hochverbleites by construction, with high compression gasoline with a high octane number . AvGas 100 fulfills these requirements (high lean rating, high lead content). Smaller engines of the 1940s and 1950s were designed for low-lead or unleaded fuels that were common at the time. AvGas 80/87, for example, was only leaded as much as is necessary to achieve the relatively low knock resistance. With a correspondingly good base gasoline, AvGas 80/87 is definitely unleaded.

A few years ago there were different types of AvGas around the world, but for environmental reasons (emission of lead and lead poisoning by tetraethyl lead ) only one leaded type (AvGas 100 LL, "low lead", reduced lead content) is now available in many countries .

In the past, there were both highly leaded variants ( AvGas 108/135 : 0.84 g-Pb / L, AvGas 115/145 : 1.28 g-Pb / L) and variants with a lower octane number ( Avgas 73 ), but these were not commercially available more are offered.

For older high-performance aircraft engines , especially in machines from the time of the Second World War and afterwards, which require very high octane numbers above 100, the corresponding fuel must be produced separately or provided with special additives to ensure trouble-free operation. The types AvGas 108 and AvGas 115 should be mentioned here.
These special AvGas types, which are very expensive today, can be found primarily at historical air shows and aircraft races such as the Reno Air Races . A very similar “racing fuel” is also used for the lower classes in drag races.

Manufacturing

AvGas 100 LL is - like petrol - a blend of different components, such as:

the synthetic light alkylate being the main component of the mixture. AvGas also contains various additives such as an antioxidant, anti-icing additive, corrosion inhibitor and a conductivity improver.

consumption

In Germany, around 13,000 tons of aviation fuel were used in 2015, compared to 18,226,000 tons of motor fuel, a negligible amount. No AvGas is produced in Germany, the entire amount is imported from abroad.

taxation

This section needs to be revised. Details should be provided on the discussion page under Revise: Taxation Section . Please help to improve it , and then remove this flag.

In general aviation , every type of aircraft fuel has been subject to mineral oil tax since 1976. Aviation fuel (AVGAS) is taxed more heavily in Germany than car fuel. There are here by applicable Mineralölsteuergesetz per liter 0.721 Euro mineral oil and additionally, to the sum of untaxed liter price and energy control another 19% sales tax levied. In September 2008 a liter of AvGas at the Bonn-Hangelar airfield cost EUR 2.32. A model calculation on this basis results in 1.23 euros as the untaxed price per liter. Including 0.721 euros in mineral oil tax, this equates to 1.95 euros per liter, and together with 19% VAT it makes 2.32 euros. In this example, the state tax share is therefore 47%. At MOGAS, the mineral oil tax share is slightly lower at EUR 0.655 per liter. The higher price for AVGAS compared to car gasoline is due to the very low production volume of this particular type of gasoline.

For commercial aviation, on the other hand, there is extensive tax exemption for the transport of passengers and freight . Internationally, the Chicago Convention ( ICAO ), which has existed since December 7, 1944, applies internationally , in which all member states have made a binding commitment to the tax exemption of aviation fuels on international flights. This tax exemption is specified in directives within the EU. According to this, there are basically several cases to be distinguished.

  1. Case (international, commercial flight): The aviation fuel is completely tax-free according to the ICAO agreement.
  2. Case (national, commercial flight, turbine aircraft with kerosene as fuel): Only national sales tax is charged; there is no mineral oil tax.
  3. Case (national, commercial flight, piston engine aircraft with AVGAS as fuel): The national sales tax is levied. National legislation determines whether an additional mineral oil tax is levied.

The EU allows member states to deviate from this regulation and to introduce taxation nationally or through bilateral agreements between member states.

For so-called factory traffic (commercial traffic by non-aviation companies) in October 2007, a test case before the tax court in Düsseldorf also confirmed exemption from mineral oil tax and justified it with EU guidelines. That was later withdrawn, i.e. H. the financial administration has prevailed. Now, in Germany, the tax exemption for aviation fuels is limited to airlines whose direct business purpose is to transport paying passengers or freight. This also includes taxi flights and the commercial dropping of parachutists.

Alternatives

Due to the high price of AvGas spread in recent years in Europe increasingly called Mogas (short for Mo tor gas oline). This corresponds exactly to gas station premium gasoline with a few additives. Some of the classic aircraft engines (such as many versions of the four-cylinder Lycoming O-320 , as it is installed in many Piper and Cessna types) can be operated with MoGas without any modification, others have to be modified at great expense. With the compulsory admixture of bioethanol in motor fuel since 2007, the approvals for the use of MoGas expire if it contains more than 1% alcohol. That is why several mineral oil processing companies have been offering the lead-free AVGAS UL91 since the end of 2013.

Since the beginning of the 1990s, there have been efforts in general aviation, especially for small aircraft with piston aircraft engines, to use diesel fuel and kerosene as an alternative to AvGas. Different construction principles are followed. There are four-stroke diesel engines , two-stroke engines as well as Wankel engines . The main advantages of diesel engines are their lower consumption and - depending on the region - often cheaper fuel. Due to the compression ignition process and the high compression pressures, however, diesel engines are more robust and therefore heavier. The higher weight means a disadvantage compared to conventional aircraft engines.

The companies Société de Motorisations Aéronautiques ( SMA ) (part of the SAFRAN GroupSMA), Centurion Aircraft Engines (formerly Thielert ) and, more recently, Austro Engine offer market-ready and approved diesel and kerosene piston aircraft engines . Other manufacturers are Wilksch, Mistral and DeltaHawk , whose engines are currently only used in experimental aircraft and drones. The engines produce between 88 kW and 257 kW (120 to 350 hp). Thus, in terms of performance, they are suitable for powering most single and twin-engine small aircraft. In the performance classes beyond that, turbines are usually used ( jet turbine and turboprop ).

See also

literature

Individual evidence

  1. ↑ a b c d e f Exxon Worldspecs (PDF; 1.5 MB)
  2. ↑ a b Shell: AVGAS 100LL (<0.1% benzene) ( Memento from December 26, 2014 in the Internet Archive ), accessed on December 26, 2014
  3. ^ A b c d Chevron - Fuels Technical Review. ( Memento from March 19, 2009 in the Internet Archive )
  4. ↑ a b shell.com: Access to Aviation Fuel Specifications. ( Memento of October 1, 2012 in the Internet Archive ) (accessed on September 26, 2012).
  5. ↑ Historical US Aviation Gasoline (Avgas) Specifications ( Memento of July 20, 2011 in the Internet Archive )
  6. ^ Avgas 73
  7. ↑ AvGas-Blend ( Memento from May 25, 2005 in the Internet Archive )
  8. ↑ Specs (PDF; 320 kB)
  9. ↑ a b MWV: Annual Report 2016 , accessed on November 26, 2016.
  10. ↑ Customs online: Tax rates for energy products according to § 2 Paragraph 1 EnergieStG (accessed on September 16, 2012)
  11. ^ Convention on International Civil Aviation (Chicago Convention) of December 7, 1944 ( PDF ), Art. 15 and 24
  12. ↑ "Council Directive 92/81 / EEC of October 19, 1992 on the harmonization of the structure of excise duties on mineral oils" and Art. 14 of the "Council Directive 2003/96 EC of October 27, 2003 on the restructuring of the Community framework for taxation of Energy products and electricity ”, see also Energy Tax Act (Germany) and Eckhard Pache: Introduction of a kerosene tax on domestic German flights . Ed .: Federal Environment Agency. 2005 ( PDF ).
  13. ↑ Directive 2003/96 / EC, Art. 14 (2)
  14. ↑ AVGAS UL91