"Kurt R. Todoroff" wrote in message
...
While dumping fuel in the F-111, at least minimum afterburner thrust was
required to ignite the fuel stream. Non-afterburner core thrust possessed
insufficient temperature to ignite it since the fan mass flow mixed with
the
core combustion products, thus lower its temperature. I would be
interested to
know if any turbojet fighters had a fuel fump mast near the engine
exhaust, and
if so, could their core thrust alone ignite the fuel stream.

John, I had a copy of the F-14A flight manual until my last move. I seem
to
remember that the Tomcat dumped its fuel using only the fuel boost pumps
(no
fuel tank pressurization), which yielded a somewhat low fuel transfer rate
through the dump mast. Did the low fuel transfer rate effect a low fuel
exhaust velocity through the dump mast, thus causing the potential for the
flame to contact the fuselage?

Been so long, I can't remember, but that sounds right. But it was
prohibited and the 100 foot flame trick would work in A/B (don't ask, don't
tell).

The F-111 normal fuel dump mode was accomplished with fuel tanks
pressurized.
If memory serves me (I no longer have my Vark flight manual either) normal
fuel
dump transfer rate was approximately an order of magnitude greater with
tanks
pressurized than with tanks unpressurized. The F-111 had no restriction
on AB
use during normal fuel dumping operations, but (again) I can't remember if
it
had AB use restrictions during non-pressurized fuel dumping operations.
Perhaps there was language contained in a caution.





Kurt Todoroff


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Consent, not compulsion.