Re: airplane fuel question

From: (Archibald McKinlay)
Organization: McKinlay & Associates
Date:         14 Aug 95 03:43:35 
References:   1 2
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In article <airliners.1995.1202@ohare.Chicago.COM>,
(SteveL3081) wrote:

> There are three fuels in common use, AV80, AV100 and Jet-A.
> AV80 and AV100 are highly filtered and colored gasoline. Jet-A is almost
> kerosene and inexpensive in quantity.  A Jet engine will burn almost
> anything that  has the right number of BTUs per pound.

First, the basics are AVGAS for props and Kerosene for jets.

Pistons require certain burning cycles and addititves based upon
environemntal factors so they are colored for easy identification.  They
are also colored so that you can tell when a local pump jockey has stolen
some for his corvette, besides the fact that it smells in the cockpit when
using AVGAS.
Commercial aircraft use Jet A as you've heard is assured pure through
multiple filtrations and inspections.  Military jets use several different
grades.  Grade 80/NATO F12 is red. Grade 100 is green and has no NATO
equivalent. Grade 100/NATO F18 Low Lead is blue. 155 (non NATO) is purple.

Jet Fuels:
Jet A, kerosene, without icing, freeze point at minus 40C, has no NATO
equivalent.  Jet A+, kerosene, with de-icer, freeze point minus 40C, non
NATO.  Jet A1, kerosene, without de-icer, good to minus 47C. Jet B, wide
cut, turbine fuel without de-icer, freezes at minus 50C.  Jet B+, wide cut
turbine fuel , with de-icer, freezes at minus 50C. JP4 freezes at minus
58C. JP5 freezes at minus 46C. JP8 is jet A1 with de-icer, freezes at
minus 50C.

The JP series is military fuel. These fuels were special purpose, to have
higher flash points to stop shipboard fires in the case of JP5.  Used only
for Blackbirds in the case of JP8. US Air Force and all land abses use
JP4, all shipboard aircraft use JP5. You cannot switch back and forth
without consequences as the fuel nozzles are maximized for use with one or
the other.  JP5 is thicker and will not burn well in Air Force engines or
commercial engines. JP8 is hopeless in a JP4 engine without a nozzle
change. Some JP5 engines require a lever to be switched when fuel types
are switched. CHECK YOUR MANUAL!

Truth arises from disagreement amongst friends, D. Hume (Scotland)
       eine Flucht nach Vorn machen, make a retreat forward
Loved and Missed, so Work Together and Rejoice, Phillipians 4:1-13
Archibald McKinlay, VI    Booz€Allen & Hamilton/McKinlay & Associates
Software Safety Engineering and Management