wrote:
Has anyone here been certified to actually work on a jet engine, how would
you keep from exceeding 620 degrees egt, the fuel control cant operate under
the avgas parameters in correcting the egt, the retired af person does not
appear to know anything about a jet engine. In a J-57 where you have 16
stages of compression prior to injecting the fuel in the combustion chamber
how would you bleed off enough air and still maintain power using avgas, the
combustion chambers and rest of the hot section can not take the extreme
heat of regular avgas, the flashpoint is too high compared to jp-4 or
similar fuel. How could the fuel control work properly when it is lubricated
by the jp-4. please tell me

Not all jet engines used jet fuel for lubrication, not all jet
engines are axial flow and if I recall correctly the USAF stopped using
JP-4 years ago. Ever heard of JP-5 or JP-8? The fact remains the B-36
and C-123 used avgas in their jet engines. I never worked on either but
I worked with men who did. The B-36 used four J47-GE-19 jet engines on
take off, high altitude and for dash speed. The C-123 used J-44R3 and
J-69 engines. In neither aircraft were there separate tanks for jet fuel.

As for jet engines while I was not a jet mech I worked the engine
instrumentations systems on C-130A, HC-130, AC-130, KC-135, C-141, T-33,
T-39, F-4E, UH-1P, HH-3, MH-53, UH-60, MH-60, several recips and a few
aircraft I will not mention.

As for your J-57 example I assume you have been looking at cut away
pictures. OK, let's do that. Take a look at the size of the inlet. It is
much bigger than needed to compress the air for combustion. Guess what,
that's done on purpose. It's done to take in a volume of air to cool the
engine.

Now tell me all about your experience with jet engines. Tell me all
about your vast experience that leads you to question my experience.


Dan, U.S. Air Force, retired