Reno 2011

[AlisoBob]

I keep thinking of these two "Wheres Jimmy?" photos...

In one hes hard up against the panel

In the other hes slumped, down in his seat.

If you ever sat in a Mustang, you would know its impossible to pull aft stick in either of these positions...... so whats commanding the elevator to do so?

Everyone I know heard a loud bang as the pull up began. Everything thinks it was the tailwheel being forced out by the G force. Perhaps it was the elevator push rod failing, although I dont know how it could be so loud?

Maybe it broke silently, and it was the tailwheel lock failing that made the bang?

I got some photos of the Ghost cockpit somewhere... I'll show you guys how cramped it is..... and how pulling back on the stick unless your sitting upright with your ass in the seat looks impossible.

[Tharrell]

What triggers the tail gear?
Is it triggered independantly of the wingwheels?
Do you suppose his seat collapsing , if it did, had anything to do with the tailwheel deploying?
I mean, is there something he may have reached for or hit when/if the seat collapsed?

I still can't get past that video.
In crude terms from a person with very little aviation knowledge, it looked like the plane was doing a loop and almost just missed the crowd.
In other words, with just a little more altitude when it started, it looks like it could have just missed everyone before it crashed.
From level flight it shot up verticle, then on the way down it was still trying to pull upright, although inverted.
Like the stick was being pulled back.
That's one of those things you see that you wished you never had.
I'm with you Bob, ready to get this year over with.

[FZ1426]

At that speed the elevator doesn't necessarily need to be pulled back for the aircraft to pitch up.

The faster the aircraft goes the more downforce is being generated by the horizontal stabilizer. The trim tabs job is to counter this downforce by "trimming" the elevator down to make the airplane flyable. Once that trim tab departs the aircraft it is no longer producing a nose down force on the elevator and the elevator basically reverts to it's natural faired position, which at that speed allows the horizontal stabilizer to produce the huge nose up force that causes the pitch up and G-LOC.

The picture you posted shows that LH trim tab deflected "up" causing the elevator to produce a (nose) downforce. Once it broke off it was all over.

"Trim" is really a misnomer. It is what allows the aircraft to be flown over a wide range of speeds. Without it an aircraft can only fly within a very narrow speed range before the stick forces become impossible to maintain.

[AlisoBob]

What triggers the tail gear?

The tail wheel assembly weighs a few hundred pounds,, at 10+g , thats a 1,500 pounds +. It just blew through the locking mechanism.

[AlisoBob]

At that speed the elevator doesn't necessarily need to be pulled back for the aircraft to pitch up.

If you look closely at the elevator hinge shadow line, and the position of the counterweights... its clearly pitching the nose up and over.

[FZ1426]

What's very odd (as you pointed out yesterday) is the asymetry of the tabs in the picture from behind. Even the elevators themselves look like they're asymetric with the LH looking like it's up a little while the RH side is very faired.

I don't know about this airplane but I know some other P-51 guys do some weird experimental things with the control rigging and CG to reduce trim drag and optimize it for high speed. That's the beauty (or not) of an "experimental" type airworthiness certificate. They can do whatever they want, even change the stick and/or seat position or deliberately alter control surface position from standard.

Regardless, at high speed the amount of deflection of the elevator needed to produce a pitch change is imperceptable to the eye. I'm not familiar with the P-51's elevator control design but no doubt one tab breaking off at that speed while the other is still trimming has got to tweek that mechanism badly.

Doesn't matter. Once that initial 10G pitch up blacked him out, his head weighed about 350 lbs for the rest of the flight. It wasn't going to move, nor were the elevators going to move from whatever position they assumed once the LH elevator nose down trim force was no longer present.

From the pictures, given the aircraft was rolling left, it seems to me the stick may have been stuck between the left side of his head and left shoulder.

Sad to have to see a guy passed out like that.

[Mik329]

I never read much into Hannah's close call until the last couple of days but it sure sounds very similar. Did the tail wheel break through in his case? I just read that telemetry has shown an 11 g pull up, maybe Bobs was not as much? Eithey way, like FZ said- it sure is a bummer he was out cold and didn't get that chance to even try to recover. Bummer a couple more people passed Ive watched this over and over and I'm still amazed that there was no fire, it would have been so much more tragic.

[AlisoBob]

I cant even comprehend if the split "S" went the other way... or if he lawnmowered the length of the Grandstand.....

As bad as this is, it was a slap on the wrist.....

[AlisoBob]

I believe Hannah's tabs were the OEM phenolic type, and he GG's were aluminum replacements.

[freeride588]

I cant even comprehend if the split "S" went the other way... or if he lawnmowered the length of the Grandstand.....

As bad as this is, it was a slap on the wrist.....

You had mentioned this before bob and that is what i keep thinking about. The damage that it would have caused would have been devastating. When you look back it was a miracle more people were not killed.

[AlisoBob]

Is a miracle that in 5000+ acres that incompass the Stead Airport complex, it came down where it did.

Fate is weird sometimes.....



Got a new photo sent to me....



wow.....



Trim tab present on the way up


Coming loose....


Off........

Its looking more and more like the actuator failed.... pitch up.... tab fluttered.... fell off.

[Kuma]

I'm amazed there was no explosion, that too would have multiplied the results.
The accounts of the photagrapher are sureal.

[Mik329]

In watching alot of this on you tube, I've noticed some really screwed up comments that people leave in the comment sections. Really.... dont these idiots have anything better to do. I'd like to drop them in a pit, pour gas on them and light em' on fire

[Tharrell]

That's just people man.
Stupidity and insensitivity are abundant.
Try to overlook it.

[Mik329]

http://www.warbird.com/voodoo.html

[Tharrell]

I wonder what thoughts are going through Hannah's mind.

[Slomo]

I fail to see how a missing trim tab would have any effect on what went on here. Once it's gone, I would think it would be as if it were in a sreamlined position? Flaps and ailerons don't look as if they are in any weird position other than I would think a concious pilot would have been bending the stick heavy trying to pull out. Things look as if it was flying straight and level, ie... no stick input...

We had a Canadian Snowbird do almost exactly the same thing a couple years ago. Turned out it was seat restraint failure.

[FZ1426]

http://s55.photobucket.com/albums/g124/ ... w_pass.mp4

[AlisoBob]

http://vimeo.com/29519344

A video of the Unlimiteds up to the point where Jimmy lost control

Good video and sound.....

When Jimmy goes "past 90" degrees of bank, the chain reaction starts...

Starting to look more and more like pilot error....

[FZ1426]

Wow. Almost looks like a classic accellerated stall. This can happen at high speed/bank angle. The shorter the wing the higher the AOA required to maintain G and/or turn rate, and the closer you are to accelerated stall.

Except for Rare Bear that thing looked like it had the shortest wing out there. That means he was closer to the hairy edge than everyone else. I think he found the edge of the envelope as far as shortening wings goes...

If it was an accellerated stall, the momentary upset/unloading of the airframe could have caused stress on the elevator/tab system setting up the failure, causing the tail wheel deployment and/or causing him to overreact and exacerbate the g issue.

That picture of the asymetric elevator from behing still holds a lot of clues. Did the RH elevator fail causing all the load to be carried by the LH side and cause the abrupt roll to the left?

Either way it looks like he had time to roll it relatively wings level before passing out. If only he had reduced the power also it may have been able to climb out and not roll over into the ground.

I'd be willing to bet that's the one thing Hannah did differently. But he was not dealing with an accellerated stall. Pulling the power after a AS would be counter intuitive.

Maybe the pilot error was taking command of a dangerously modified machine in the first place...

[AlisoBob]

I think it was just an simple over-correction.

When he went past 90 degrees, the nose started to tuck under so Jimmy had to instantly push stick forward and roll right to save it.... which he did... but then he had to instantly pull aft stick again to contuine with the turn and avoid crossing the "deadline"... I think he pulled too hard, and thats all it took to start the chain reaction rolling.

I think the mechanical aspect of the crash was caused by the pilot, and not the other way around....

[Tharrell]

You can see the tab come off at 9:00.
That's an excellent view of the final seconds of flight.

[AlisoBob]

From Matt Jackson, a seasoned Reno Unlimited pilot....


"....you will notice that the elevator flutter did not occur until almost half way through the pull indicating that the flutter did in fact not cause the pitch up. Its pretty evident with the violence of the pull up that Jimmy was put to sleep almost immediately ~ Matt."

[Mik329]

Maybe the pilot error was taking command of a dangerously modified machine in the first place...


Posted: Sat Sep 24, 2011 8:38 pm    Post subject:
I think it was just an simple over-correction.

I think the mechanical aspect of the crash was caused by the pilot, and not the other way around....

I'm with you guys here. Add in the fact that the pilot was probably way past his prime in being able to withstand the aero medical factors associated with this type of flying.

[FZ1426]

I think it was just an simple over-correction.

When he went past 90 degrees, the nose started to tuck under so Jimmy had to instantly push stick forward and roll right to save it.... which he did... but then he had to instantly pull aft stick again to contuine with the turn and avoid crossing the "deadline"... I think he pulled too hard, and thats all it took to start the chain reaction rolling.I think the mechanical aspect of the crash was caused by the pilot, and not the other way around....

Yes. Exactly the reaction he would have made to address the accellerated stall...and to avoid flying into the ground immediately.