As Ed Anderson demonstrated, Bill is absolutely correct.  You may recall
that Ed simultaneously ignited his fuel tank and 5 gallon fuel can while
refueling his plane (static electricity).  Adding  to the fun, he dumped
burning fuel on the top of the wing and ground below it while stepping

away

from the conflagration.  Ed kept his cool, set the burrning fuel can

down a

few steps away and dropped the fuel cap into the filler hole

extinguishing

the flame from the tank.  Of  course in Hollywood, there would have been

a

huge explosion.  The real world is obviously far different than the

movies.

Bill,  I'm finally working on the FEA request stuff for the adapter

plate.

Sorry for the delay, its been a madhouse here lately.

Tracy Crook
tcrook@rotaryaviation.com
www.rotaryaviation.com

While I don't debate that in almost every case a tank containing liquid fuel
will not have a fuel air mixture inside the tank that is not past the rich
limit of combustion, it is possible under the right circumstances. It really
depends on the vapor pressure of the fuel and the ambient temperature. If it
is cold and the fuel has a low vapor pressure, you can get a combustible
mixture inside of a fuel tank that still has liquid fuel in the tank. It has
happened to some aircraft due to lightning strikes. I recall reading about
one incident being traced to the chain which retains a fuel cap conducting
part of the strike and sparking inside the tank, which caused an explosion
and the subsequent loss of the aircraft. There have also been some Airforce
planes which had documented fuel tank explosions on the ground. I would not
rely on the fact that 99% of the time you will be safe with some liquid fuel
in the tank. Other things which can cause a problem are a leaking fuel cap
and a vent which rams air into the tank.  You guys do what you want, I just
don't feel comfortable with the pump in the tank, and I would be remiss If I
did not share my concerns. It's up to the individual to decide what they are
comfortable with. I think you would be fine 99% of the time with the pump in
the tank, but why risk it? A pump not in the tank will result in more
possible leakage points, so pick your poison.

Monty

Kerosene, possible.  Gasoline above about -40F or something in that range,
basically impossible.  Essentially ALL cars have pumps in the tank nowdays.
If there was a 1 in a million chance, about  10 cars a month would be
blowing up.
It would be in all the papers.  I am a SERIOUS safety nut {just ask the guys
that have read my safety rants over the past few years  :-)   } but this is not
a real issue.  We need to be safe, but also recognize where the real problems
are and focus our limited time and funds on those.

OTOH, you can do whatever you want to, it is still a free country, regardless
of what Osama would like.  ;-)

Bill

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