When this
F-14 Tomcat took off, there was a large bang and a fireball backfires out of the
exhaust.
Mark Platt
:
The explanation is simple. After the Tomcat has been fueled (usually topped
off) it will sit for awhile waiting for the next hop. As the fuel begins
to warm up inside the bladder(s), it will expand. The fuel bladders can
only hold so much fuel. The Tomcat has a large fuel vent pipe near the
pivot point of the tail hook. I am very familiar with it, because
I've smacked my head on the damn thing many times. Just ask any Plane Captain
who's worked around F-14's. Anyway, This vent pipe is notorious for
leaking (venting) fuel on the deck. It is not uncommon to see a five gallon
bucket under the belly near the tail hook area to catch venting fuel. I
have seen this fire behind the Tomcat on many cat shots, especially on
a hot day in the South Pacific. The Tomcat in your photo is near the end
of the cat shot. The after burners are lit. As the aircraft blast's off
forward, residual fuel in the aforementioned vent system momentarily
dumps out. The Jet-A gets into the heat of the exhaust (very hot) and flashes
very quickly, creating a momentary fire. I too was on the Kitty Hawk
in 77-78 with VF-114. What a blast....
From Animal112:
It's a
compressor stall caused by a change of airflow into the engine.
From Supulveda:
that fireball
is result of corrosion (salt spray) in afterburner spray
rings.
pressurized fuel builds up in the ring, breaks away the corrosion and dumps
on the deck in the form of the fireball you photographed
AO2 James Floyd
I was there,
don't you remember that the water always had a flavor of JP (jet
fuel) because
they always kept either water or jet fuel in the tanks to maintain
ballast well, there was enough of a flammable mixture of JP
in the water they were boiling for the steam for the catapult that the
AB on the F-14 ignited it. This was not a first occurrence I have seen
it more than once on different ships, it happened a lot with
F-4's hope I cleared your mystery. AO2 James Floyd -- VA-94 TAD AIMD
this cruise in reference.
A
CURRENT F-14 GUY 6-24-99
The explanation of
a corrosive/salt buildup is a definite possibility, along with (more likely)
an afterburner blow-out. This only means the AB blew
out momentarily, and then relit-- the buildup of fuel in the spraybars / nozzle
during the moment the AB was not lit caused the 'puff.' While
certainly not common, this is not unheard of. The AB usually
relights itself, or is relit by the pilot cycling the throttle (s)
out of AB and back again.
ex-AMS2 "Country"
The fireball
could have been caused by ingesting a foreign object,
called FOD.
Steven
Hesley army.mil
In regards to
your mystery detonation on the F14 cat shot, I would have to rule
out compressor surge. This is normally caused by disruption of air
flow into the compressor and on take-off most often by strong cross winds.
Judging from the waves and cat steam it appears the bow was pretty much
into the wind eliminating the crosswind problem.
If you'll notice
the fireball is definitely below the horizontal axis of the port engine.
This would seem to rule out any kind of a backfire. Engines
don't throw curve balls. I would conclude that the cat steam ignition
theory is the correct explanation in this case. Notice how the flame
appears closer to the deck than the engine, and appears to follow the convection
of the escaping steam and engine exhaust.
S.F.Hesley
AMSTA-LC-CAA
DSN 786-5717
CPOMEA RN Wayne
Clancy
concerning the
'cough' from the F14 on page 'http://YellowAirplane.com /photos /CV63_F14_6.html'
I can absolutely 100% rule out any such nonsense as JP in the
steam. No matter what water was stored in what tank, boiler
feed water is purer than pure, normally better than 1ppm of
dissolved solids contamination and certainly never any JP.
That's the standard for the Royal Navy and I can assure you that
American fleet carriers will be just as high a standard, in fact if
there was enough JP in the feed water to burn, the fireball would have
come along time before from the boiler room and now there wouldn't even
be a deck to fly from.
From a gas
turbine point of view, if the aircraft successfully took off
and flew its op then I'd go for an AB related problem. If the plane
crashed in a fiery heap, I'd go for a catastrophic component failure
(FOD damage?), compressor surge or stall serious enough to affect
combustion during the rather sensitive manooeuvre of take off is
doubtful in a well designed modern engine and intake system.
ex CPOMEA RN Wayne Clancy
As you can see,
there is a little conflict of information here. To tell you the truth,
the more technical the explanation, the more I believe it. If anyone
has any more information,
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