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.

Big John