GS> But it's not Jet-A.  The SR-71 burns a highly refined fuel known as
 GS> JP-8.
Actually, the SR-71 uses JP-7.
[From an unknown website, via M.D.]
Jet fuels in the U.S. have evolved as follows:
     JP-1 was the first jet fuel specified in the US (1944).  It was a
kerosene with  a freeze point of -77 oF and  a flash point temperature
of 109 oF minimum.  However, its availability was limited to only about
3% of the average crude oil.
     JP-2 (1945)  was an experimental fuel that was found to have unsuitable
viscosity and flammability characteristics.
     JP-3 (1947 to 1951) was the second operational fuel.  It had a high
vapor pressure similar to aviation gasoline.  Due to its high vapor pressure
and the fact jets flew at higher altitudes than reciprocating engine-powered
aircraft, fuel boil-off losses and vapor lock were problems at high 
titudes.
     JP-4 (1951 to 1995)  fuel, also designated as NATO F-40 and Jet B, is a
blend of gasoline and kerosene, it has a reid vapor pressure restriction of
2 to 3 psi to reduce vapor lock problems.  Its freeze point is -77 oF and has
a flash point temperature around zero oF (not a specification requirement).
JP-4 was the US Air Force's primary jet fuel from 1951 to 1995.  In the mid
1980's an anti-static additive was added to JP-4 for fire safety reasons
     JP-5 (1952 to the present)  fuel, also called NATO F-44, is used by the
Navy.  It has a 14 oF (Min.) flash point temperature.  This kerosene fuel is
currently the US Navy's primary fuel and was developed mainly due to fire
safety concerns on naval ships.  This fuel has a freeze point temperature
of -51 oF.  JP-5 does not have the anti-static additive.
     Jet A and Jet A-1 (1950's -present)  are the two fuels used by the
commercial airlines and both fuels have a 100 oF (Min.)  flash point
temperature for safety reasons.  Jet A has a freeze point of -40 oF whereas
Jet A-1 has a freeze point of -53 oF.  For this reason, Jet A being more
available and therefore more widely used. The commercial fuels in the US are
not required to have the anti-static additive and generally do not have the
additive.
     JP-8 was first introduced at NATO bases in 1978, also called NATO F-34,
and is currently the US Air Force's primary fuel.  JP-8 is very similar to
Jet A-1.  JP-8, however contains an icing inhibitor, corrosion/lubricity
enhancer and anti-static additive.  Conversion to JP-8 was virtually
complete in 1995 and was accomplished for fire safety and combat
survivability reasons.
     JP-6 (1956)  was developed for the XB-70, is similar to JP-5 but with a
lower freeze point (-66 oF) and has improved thermal stability.  Its flash
point temperature is not a specification requirement.
     JP-7 (1960's)  was developed for the SR-71, has a low vapor pressure and
excellent thermal stability for high altitude and Mach 3+ operations.  Its
freeze point is -47 oF and has a flash point temperature of 140 oF (Min.).
     JPTS (1956) was developed for the U-2 and is a highly refined kerosene
with a low freeze point of -64 oF and a thermal stability additive package
(CJFA-5).  Its flash point temperature is 109 oF (Min.).
Regards,
  Jim
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