Big John wrote in
:

On Sat, 17 Nov 2007 21:37:03 -0500, Dudley Henriques
wrote:

Bertie the Bunyip wrote:
Dudley Henriques wrote in
:

Bertie the Bunyip wrote:
http://www.youtube.com/watch?v=F4_iJ...eature=related

http://www.youtube.com/watch?v=ZN1lC...eature=related

http://www.youtube.com/watch?v=9txDhi5wC2A

Have my own notions, but would be interested from a pros
viewpoint.

I'm assuming that mechanical was not a factor in any of these,
BTW.Might have been, but it appears that in each case the pilot
went in with no commital gates and no escape route.

Bertie
Can't say much about the Extra (at least it looked like an Extra)
but the Hurricane and the King Cobra are accidents I've been
involved in with safety discussions within the war bird
demonstration community.


OK, the first one should have been the T6 slow roll where he dished
out in the end.(orange one in south america?)
Looks like he had nothing even beginning the roll and had completely
lost the plot by the time he reached even 45 degrees and should have
just thrown it away at that point.
To me, the KC accident looked like the result of a way too low
energy state going through the top gate. He should have had at
least 150 indicated inverted on top but it looked like he lost his
energy to drag going up the up line by pulling too much g. He was
practically dead in the water on top but apparently at fairly high
power. This looked like it torqued him in roll pretty good and he
lost it coming through the gate. He recovered as the angle of
attack narrowed back into the work range but by then he was
committed way too nose low and had no radial g available to affect
the recovery.


OK, pretty much as I saw it as well (though I ould never have put it
so well!) But it seems to me he should have been formulating some
sort of plan to get out as he neared the top of the first loop and
saw it all going wrong. Never flown anything as powerful, fast and
heavy as that doing aerobatics, of course, but it seems to me he had
only two options after he passed 90deg; a hammerhead might have been
a bit ropey at that altitude in that airplane, and I don't know if
they're even on the menu in that thing. A hammerhead being ruled out
for whatever reason, I'd just pitch over forward hard and bump my
way out if the airspeed was that far gone. The bottom of the list
would be to pull hard and then roll out, which is what he did,
intetionally or otherwise, but if he had pulled a bit harder a bit
earlier, he'd at least have exited the torque roll a bit more nose
down which might have avoided the secondary problem.
Did it have fuel injection? Was he having to think about avoiding
negative G?
The Hurricane looks like it will come down to a simple brain fart.
The guy was very qualified and had experience. So far it looks like
he simply committed to a Split S below his minimum AGL parameter
for the Hurricane. This one is very similar to the Thunderbird F16
accident at Mountain Home AFB where the team lost a Viper. Brain
fart!


Again, exactly as I saw it. He was screwed the second he rolled
over. Reason I ask is I was just wondering how good my eye was after
so long away from aerobatics.


Bertie

Didn't see the T6 roll on these links, but I think I remember the
crash. The 6 has a lousy roll rate and loses energy like a brick when
rolling and doing 2 in a row while down in the weeds can bite you in
the butt dishing out. More than one guy's lost a T6 this way.

The Cobra; his best chance would have been to anticipate the torque
roll carrying all that MP and throttle back to idle before it torqued
out on him, then rolling to the nearest horizon after a mistake like
he made on the way up. In certain conditions you just don't get a
second chance in prop fighters.


I didn't see any T-6 video and roll accident but:

I have lots of time in T-6. If you slow roll the bird the engine will
flood out inverted (with the negative G on the float type carburetor)
and this loss of power will almost always cause you to dish out unless
you immediately apply very large control inputs in all three axis. If
you are on the deck when doing the slow roll then you will probably
buy the farm before you can reestablish control of bird.

The bird can be slow rolled and engine not cut out by turning off the
fuel a few seconds before you start the roll and the engine will
continue to run on fuel in carburetor through out the roll and you
will have normal control authority to do a good roll. Then turning the
fuel back on.

I never had the engine quit when I turned off the fuel to demo a slow
roll to a student but doing it on the deck might be the one time the
fuel flow to the engine did not immediately return to normal as soon
as you were back straight and level ( Of course if you were back
straight and level and engine went dead, and you could not get
restarted, you would have the opportunity to belly bird in and survive
vs cart wheeling if you dished out of roll.



Here it is John,

http://www.youtube.com/watch?v=Y7eYhlm9FJ8

Doesn't look like he lost power. Maybe the airplane has been modded.



Bertie