Big Crash at Reno

[Lost in Saigon]

I don't know what the great mystery here is. He's got roll instability that the other non-modified Mustang does not. He chopped up this airplane and it didn't fly like it should have. Are we surprised? No.

-drl

You make it sound like this is the first time anyone has raced a modified Mustang with clipped wings......

http://www.mustangsmustangs.com/p-51/p51variants/AirRacers/PreciousMetal.2.jpg

http://images.rcuniverse.com/forum/upfiles/32782/35856_11603.jpg


http://www.mustangsmustangs.com/p-51/p51variants/AirRacers/RedBaron.1.jpg

http://www.mustangsmustangs.com/p-51/p51variants/AirRacers/Stiletto.1.jpg


http://www.mustangsmustangs.com/p-51/p51variants/AirRacers/Strega.1.jpg

[wiggy]

Academic I know in the (tragic) circumstances but I'm another one not "buying" some elements of the GLOC graph presented into evidence earlier.

Am I misreading it or it is seriously suggesting that a progressive "squeeze" to 5 g in 5 seconds - the green line, will lead to GLOC?

A further thought - I believe the early ballistic ejection seats could hit 20G plus - not great for the back/neck, but not necessarily an instant bone breaker either...

[Lyman]

Machinbird

So incapacitation could have caused an inadvertent input of NOSE UP, which he was pulling anyway? With a marked addition of increase AoA of the Tab, it could easily have been overloaded. Mind you, with VooDoo, we have a prior event, and I take your point. Down to metal fatigue, I'd say that it is likelier that the pilot was fine until the Tab let go. If the Tail was that asym, then a large instability enters in Roll. Also Yaw.

Again, the tab may have led to control input that was not ideal, and who would know just how much of what to input into a broken Tail? The Tailwheel lost its retention somewhere just here, prior to the climb, so it is logical to predict the highest g happened in this roll/reversal sequence.

If the remaining tab was not sufficient to keep the elevators down, they went up (asymmetrically), and could have been an additive input that was responsible for the proposed blackout.

Leeward would have instinctively wanted to climb, besides its the rule, so the 80 degree Pitch Up might have been caused by the pilot afterall?

I am not trying to draw conclusions, perhaps I'll attempt to present things a bit more tentatively.

I draw attention to the pre event G to set the stage for a loss of consciousness with a quick transient, not to establish earlier gloc.

The circulatory system makes accomodations for aging, and it is not conducive to high g manuevering, no matter the musculature. Not sure hypertension applies here. With a fit pump, muscle tone and BMI are important. Your graph tells the story.

[thcrozier]

Let's say you are happily cruising over Stead about 200 feet off the deck in your modified P-51. Your speed is about 490mph and you are trimmed for level flight.

How many pounds of force would you need to pull on the stick to induce a 12 G climb? How about a 21 G climb?

[Lyman]

It will be "x" minus"y". Where x = manual pull, and y = loss of NOSE DOWN TRIM, with the croaked Tab. Without the tab, the HS will migrate UP.

Assuming the trim is in fact ND. Any trim at that velocity is a mixed blessing, if in an emergency one wants and needs a vanilla response?

Someone a great deal more familiar may post in?

[skwinty]

I read somewhere that GG had only one operational elevator trim tab.

The other tab was fixed.

Is this correct?

[Lyman]

Correct? I could not say.

Counterintuitive? Oh yeah.

[skwinty]

Here is where I read the trim tab story.

http://www.pprune.org/6721683-post41.html

I see it comes from this forum as well.

the Galloping Ghost......... detailed pix (http://www.supercub.org/forum/showthread.php?41228-the-Galloping-Ghost.........-detailed-pix&p=512475&viewfull=1#post512475)

[Desert185]

skwinty:
I read somewhere that GG had only one operational elevator trim tab.

The other tab was fixed.

Is this correct?

One trim tab on the left elevator only.

[Lyman]

Desert

Que? Is that a make shift Yaw damper as well, then? Cheat to the left, and save on Rudder Drag? Wouldn't that be conducive to torsional vibration on the elevator hinge?

Sounds almost like, cheating.

Besides, if he has ND cranked in when level, he sure does not want it in a steep turn, nothing but drag. NU helps in the turn, so what, is he some trim monkey, constantly adjusting trim to suit attitude? That is a lot of load on/off/transit on the rig. And a LOT of wear. If he's using muscles to overcome the ND and is leaving the tab up in the airstream whilst yanked in a turn, that is just dangerous, and would (could) explain the extreme NU when the Tab croaked.

[xmh53wrench]

Quote: Lyman "Wouldn't that be conducive to torsional vibration on the elevator hinge?"

I think that is what I was sort of asking towards the end of my long post. But hadn't considered the vibration aspect, just a simple twisting of the elevators in relationship to each other. I've seen the question regarding the use of only one TT and a reason for it, asked on numerous forums but not ever have I read an inkling of reason for doing it.

[Machinbird]

One trim tab on the left elevator only. Information I've seen on other forums indicates that this might be better stated as one functional trim tab only. I have seen pictures that I will post a link to that indicate the port and starboard elevators are interchangeable on the P-51. When built back up after its substantial overhaul, GG had trim tabs in both positions. The bellcrank on the starboard elevator tab is on the top surface, and on the port elevator tab, the bottom surface. The starboard trim tab may have still been ground adjustable even if that tab was fixed. For pictures of the GG rebuild, see WarbirdAeroPress.com (http://www.warbirdaeropress.com/NewGallery/GG2009-1/index.html)
and
WarbirdAeroPress.com (http://www.warbirdaeropress.com/NewGallery/GG2009-2/index.html)
Wow, what an extensive rebuild!!

[Lyman]

The F-16 has Stabilators. They articulate on separate pins that allow deflection in opposite direction, to enhance (to put it mildly!) Roll. They of course deflect in concert, when selected for Pitch only.

If GG had one Tab fixed in ground-only aspect, and the other operable in flight, one gets the 'same' effect, though obviously the poor mans' version. Roll is enhanced along with Pitch trim. I'm going to assume the elevators remain affixed to the single Tube/hinge barrel that carries both, aligned identically.

Interesting trick. Under severe load, one can imagine an asymmetrical span wise loading on this Tube, and the potential for vibration, even flutter, or buzz. The drag of Trim, on the left, is spent on Yaw capture when turning, and makes elegant use of Drag that would otherwise go to waste. If the pilot is flying trim, mechanically, this sytem has some issues relative to load (torsional) on the tube, and on the HS bellcrank, and cables. When back driven, the system would be subject to variable loading, unless damped in some fashion, and this set up would want some serious monitoring.

Unlikely, but possible, is the loss of Elevator continuity, if the actuating frame had a break in the attach to the tube. Since control is asssumed to have been pilot/unavailable anyway, it isn't impossible that the Elevators were flapping in the airstream, following, instead of leading the flight path.

The flight path after the snap looks eerily ballistic, it is too smooth to have controls inputting directional leads.

wrench, I missed your bit about the asym tab purpose, but does this proposition sound in any way applicable?

[Lost in Saigon]

Information I've seen on other forums indicates that this might be better stated as one functional trim tab only. I have seen pictures that I will post a link to that indicate the port and starboard elevators are interchangeable on the P-51. When built back up after its substantial overhaul, GG had trim tabs in both positions. The bellcrank on the starboard elevator tab is on the top surface, and on the port elevator tab, the bottom surface. The starboard trim tab may have still been ground adjustable even if that tab was fixed. For pictures of the GG rebuild, see WarbirdAeroPress.com (http://www.warbirdaeropress.com/NewGallery/GG2009-1/index.html)
and
WarbirdAeroPress.com (http://www.warbirdaeropress.com/NewGallery/GG2009-2/index.html)

Wow, what an extensive rebuild!!

Thanks for the link. Lots of good photos there:

http://i2.photobucket.com/albums/y17/msowsun/Airline/Clipboard06.jpg

http://i2.photobucket.com/albums/y17/msowsun/Airline/Clipboard06a.jpg

http://i2.photobucket.com/albums/y17/msowsun/Airline/Clipboard01.jpg

http://i2.photobucket.com/albums/y17/msowsun/Airline/Clipboard04.jpg

http://i2.photobucket.com/albums/y17/msowsun/Airline/Clipboard02-1.jpg

[xmh53wrench]

Lyman: thanks for the explination, you would think since I spent my racing career turning right to go left, than all of that would make sense to me, but having the right TT fixed still seems backwards to me, but I will take your explanation.

Lost in Saigon: How did you manage to extract those photos? I just ordered a 1/32 kit and they would be a great source of detail, and I would like to save them to my laptop before they disappear. Thanks

Also, new long distance vid, but really shows the pitch up.
http://www.youtube.com/watch?v=VbkxKJCM4x8

[Lost in Saigon]

Lost in Saigon: How did you manage to extract those photos? I just ordered a 1/32 kit and they would be a great source of detail, and I would like to save them to my laptop before they disappear. Thanks

It is quite easy to do. Just hit "Print Screen" on your keyboard, and you take a snapshot of what is displayed on your monitor. Then open "PAINT" or a photo-viewing program like "Irfanview"(free download) and hit "Control V" to paste it. You then crop it to size and save the file.

More info: Print screen - Wikipedia, the free encyclopedia (http://en.wikipedia.org/wiki/Print_screen)

[deSitter]

Alt-PrintScreen is better - it just copies the focused application (active window), not the entire screen. There is probably a Mac and Linux equivalent.

-drl

[rh200]

There is probably a Mac and Linux equivalent.




In Ubuntu Linux if you alt print screen it will actually open a image viewer with the captured window in it, you can save straight to disk from that

[skwinty]

The thing that niggles me wrt to the single functional trim tab is this statement from the link I posted earlier.

"He was warned about the forces being put on that one tab."

Did the previous incident of trim tab failure not give cause for concern?

I know it's a human trait to believe that it can't happen to you and I hope that the rest of the racers are making suitable modifications to their awe inspiring aircraft.

Incidententally, does anyone know what happened to Learfang, the P51 with Lear jet wings?

[Lost in Saigon]

Incidententally, does anyone know what happened to Learfang, the P51 with Lear jet wings?



Crashed in 1999: P-51 Mustang Survivors: " Miss Ashley " , N57LR - serial #: 87-1002 Sights, Sounds, History. (http://www.mustangsmustangs.us/p-51/survivors/pages/87-1002.shtml)

N57LR plane crash in NV details :: PlaneCrashMap (http://www.planecrashmap.com/plane/nv/N57LR)

http://www.mustangsmustangs.us/p-51/survivors/pages/picfiles/87-1002/87-1002_05_mk1.jpg

[skwinty]

Thanks for that Lost in Saigon.:ok:

[xmh53wrench]

Lyman....did you get the chance to look at that 18 photo sequence? Am I mistaken or a does it look like the TT is in major flutter in #7a, if the GG is rolling to its right why are the ailerons showing roll to the left in #15a? or am I just all twisted around? Just curious on your take.

[Lyman]

If you have anything with the sort of resolution you allude to, I'd love to see them? PM is good.

thanks wrench

[Lost in Saigon]

More photos of the tail area:

http://i2.photobucket.com/albums/y17/msowsun/Airline/Clipboard01-1.jpg

http://i2.photobucket.com/albums/y17/msowsun/Airline/Clipboard02-2.jpg

http://i2.photobucket.com/albums/y17/msowsun/Airline/Clipboard03.jpg

http://i2.photobucket.com/albums/y17/msowsun/Airline/Clipboard04-1.jpg

http://i2.photobucket.com/albums/y17/msowsun/Airline/Clipboard05.jpg

http://i2.photobucket.com/albums/y17/msowsun/Airline/Clipboard06-1.jpg

http://i2.photobucket.com/albums/y17/msowsun/Airline/Clipboard07.jpg

[ClippedCub]

Trying to catch up. Before this tragedy happened, I had been talking to some teams about reducing compressibility drag on the Mustang Unlimteds, so I might have some unique contributions.

Haven't had time to study the video frame-by-frame but can comment in areas. Like everyone here, still putting the pieces together.

- "Could it occur, but not for long enough for the aircraft to actually stall at that G load and relieve itself?"

Dynamic stall can result in higher CLmax than the FAA demonstrated one knot/sec deceleration to the stall by hysteresis. Though on some other boards, there are claims of the telemetry being limited to 8g's. Don't know if we'll get the right number until the report, unless someone takes the time to convert the geometric flight path to g's. Since the tailwheel pops out before wings level, this might not capture the max.

- Remember a report in the past about older people being able to handle g better than the younger ones if they have any hardening of the arteries since the airteries don't expand as much to accept blood. This probably wouldn't matter much at 10+ g's, but the discussion should preclude age.

- Leaning towards the structural failure causing the left wing drop since wake turbulance would be unlikely since the wind was coming from the direction it was and was strong from the flags flying in various videos.

- "Roll Rate on this a/c is rapid, far higher than the factory model with ten feet less span. Similarly, the ailerons are half length, and it would be interesting to know if they were clipped Out/In, or In/Out. This is critical, since ailerons are airfoils, and subject to STALL just as any other."

Roll rate capability is a function of wing span-to-aileron span, and would be reduced due to the clipped wings at the tip, but at these q's, the airplane had plenty of control authority. Ailerons don't stall like wings since the leading edge is protected by the slot, but the upper surface can separate at high enough deflections.

- The racing Mustangs have an aft cg, so the elevator is deflected for nose down moment at race speeds. Some of the guys have changed the incidence to alleviate this requirement. Leeward had the one port trim tab. Voodoo had the elevator shear the torque tube fasteners on the lost trim tab side. Probably from the violent act of the trim tab fluttering and departing.

- The trim requirements in the turns and straights tend to balance out due to the aft movement of the center-of-pressure due to a shock wave forming on the inboard wing at 4 g's in the turn. Haven't analyzed it yet, and Leeeward was banked pretty good in the turn, but 6 or 7 g's probably wouldn't cause Mach buffet, looking at the pressure distribution at 4 g's. Yes, the Unlimteds are seeing compressibility drag due to the original subsonic airfoil selection.

This seems like a forum with informed, and talented individuals, and will try to contribute as I read through the thread.

[Lyman]

Roll rate is dependent on wing area/aileron/area, among other things. I see your point, as the area of the wing was not "halved" as was the aileron area. Good point.

Having a shorter wingspan reduces the inertia of the rolling moment? Less energy is needed to start, maintain roll? The aircraft is also less stable in roll.

The rapidity of the wing drop is what captivates me, not the impulse strength of the ailerons. I doubt the snap left was controls induced, more like a wing drop from loss of net lift v/v the right wing? Wake turbulence remains a possibility? Torque from the loss of structural integrity at the Tail?

Clipped wings, quick turns, eh? I am waiting for the next gen Mustang to show up with anhedral?

As to airfoil, the aileron is just a wing with a humongous cuff. And the laminar flow Mustang is sensitive to interruptions in local airflow?

[ClippedCub]

Google for the basic aerodynamic and control theory answers of wings.

Could have been turbulence from ground based items/structures, but to conclude the initial dip was from wake turbulence of the lead airplanes is unwarranted due to the wind conditions. Am sure there are some weather history websites that would have the atmospheric conditions to the hour. For this reason, am leaning toward the left wing drop as being an artifact of the mechanical failure.

Whatever the cause, Leeward did an excellent job of arresting the left roll with the right amount of finesse. Reflexes like a cat from muscle and experience memory developed over the years. If nothing else, he can be remembered for his skill.

[ClippedCub]

In response to the just prior post, that's missing now, on discrete roll rates in the turn;

There's a small right roll rate well before the left wing drop with a slight left roll rate immediately before the left wing drop. Consider these excursions to be positioning corrections. Ailerons are rate controls, as opposed to attitude controls, i.e., once a bank angle is established, aileron deflection is zero to maintain bank angle. The aircraft stopped rolling at wings level indicating the ailerons returned to neutral. The roll resumed during/after the wings level pull up.

[Lyman]

Should you include the "slight correction" needed each time to arrest the roll? Could these have been merely imprecise, instead of "positioning" inputs? Not a criticism, certainly, this is a hot a/c.

There is no shame in "hunting" a roll at 475 mph.

[ClippedCub]

Lyman, you're not a pilot, are you. No offense, but what's your background? You seem to have a Wiki knowledge of aircraft, their workings, and their operation.

[westhawk]

CC makes a good point regarding the unlikelihood of wake turbulence being a potential factor in the left wing drop just prior to the pullup. With the wind blowing, there is plenty of ground features in that area of the course which could produce turbulence. In fact it's not unusual to see race planes bobble a bit while rounding the pylons whether from wake or other reasons.

I'm not sure about the trim tab failure being the cause of the rolling moment because the turn did not appear to tighten. Instead, the airplane appears to roll towards a wings level attitude before the increase in gee loading becomes apparent. I've thought from the start that the pitch up was due to the trim tab failure, but have no idea how much forward stick force would have been required to overcome the trim change resulting from the loss of the tab force. I suspect it's quite allot.

I've never flown a Mustang or any such high performance piston single and the highest IAS I've ever flown at is 360 KIAS, Vmo for a Westwind I. (nearly full nose down trim) Trying to imagine the trim suddenly going to neutral or less at that speed doesn't paint a pretty picture. Even the simulated trim runaway can be a handful at high speed if you don't push the trim disconnect pretty fast. Such a sudden change of required control force at near 500 mph in a Mustang must be much worse. I tend to doubt that Jimmy or anyone else would have had much chance of stopping the pitchup. Perhaps the final report will contain an analysis of the stick force change resulting from the trim tab failure. It's my feeling that any substantial instantaneous force change would likely be unrecoverable until the speed fell way off. Hannah was luckier in that his airplane climbed long enough for him to wake up.

As for all the talk about control surface stalls and high speed stalls, I just don't think that's a player here. The way I see it with the info we have right now, the tab broke, the airplane pitched up and put Jimmy to sleep with his head forward and down. With the Gee loaded on, the airplane slows down in the climb and P-factor or lack of corrective control input (pilot unconscious) rolls the plane into what amounts to a half barrel roll ending at the VIP boxes. It never looks stalled and the flightpath could easily be explained by the scenario above. As time goes on, newly revealed facts could certainly justify altering the theory to align with the new facts.

Like everyone else, I'll be interested to see a detailed accounting of all the factual data available to the NTSB team when they release it. As much as I respect their analysis of accidents, I like to do my own as well rather than just waiting to read the probable cause finding. As of today, no public docket info is yet available.

[Lyman]

@Clipped Cub

Instead of pointing out what's wrong with my statements, you suggest google and then ask if I am a pilot.

Are you one? Really?

What is Leeward doing about his trim entering turns? Is he working it less Nose Down? Needing Pitch Up in the turn, he doesn't want trim Down, does he?

If he's leaving the tab up through the turn, using leverage at the stick to overcome it, for lack of time to neutral the Tab, his Nose up will greatly increase the Tab's exposure and angle to the slipstream. This greatly exaggerates the stress on the Tab. If it is at this point the Tab breaks, The Pitch Up will be disastrous, as per VooDoo.

Since the snap left was the first noticeable part of the Upset, It is reasonable to assume that this is where the Tab released its mounting.

I'm a humble Commercial Pilot, retired, without your degrees, but I venture to say I have a bit more courtesy than you.

What are your thoughts re: trim? Need a picture?

westhawk. The turn did tighten, and that may have been what caused the unwanted roll. In a steep turn, a Pitch up increases Roll into the turn. Left, in this case.

[LurkerBelow]

Found this in another forum (and this was also not the origin):

From a friend who flies corporate jets for The Limited
Good News for the future of air racing.

Our new crew member, Matt Jackson, is not only a race pilot, aircraft
business owner and aircraft owner (he also takes care of Tom Cruises
P-51)but he is also the VP of the Unlimited Racing Class and head of
the Safety Committee.

We had a long talk about the Reno crash on the way to Mojave today.

Matt believes the cause of the crash was due to The Galloping Ghost
having a CG too close to the aft limit which resulted in pitch
instability. There are instructions on the P-51 regarding no combat
missions with the aft fuel tank full resulting in an aft CG problem.
Instructions specify to empty the aft fuel tank first in flight.

During qualifying Matt watched Galloping Ghost from inside the cockpit
of Furias and could not believe how much trouble Leeward was having in
keeping the Ghost in a stable pattern around the course.

Since Leeward lives in Florida and the Galloping Ghost was modified for
racing in Calif., when Leeward picked up the Ghost for the Reno races
at the last minute, a complete flight test program had not been done
based on available information.

There is a video of the entire last lap of the Ghost before the crash
which Matt showed me. As Leeward was coming around pylon #8 at about
480 mph after passing Rare Bear, he hit turbulence which pitched his
left wing down, Leeward corrected with hard right rudder and aileron.

Just as the aircraft was straightening out, he hit a second mountain of
turbulence which caused the tail to 'dig in' resulting in a 10+ G climb
rendering Leeward unconscious instantly and resulted in the tail wheel
falling out. (broken tail wheel support structure was found on the
course). As the Ghost shot upward the LH elevator trim tab broke loose.
This can be heard on the tape, so the trim tab did not cause the
accident.

Since the Ghost was racing at 480 mph with full right rudder and the
stick full right, this is where everything stayed when Leeward blacked
out.

Cockpit camera film that was salvaged from the wreck shows Leeward
slumped over to the right in the cockpit. As a result, the Ghost
climbed up and to the right, rolled over on her back and then headed
for the box seats. Most in the box seats never saw it coming because it
came in from behind them.

Matt has had long conversations with the NTSB who call the accident a
'fluke'. They are not going to recommend canceling future races. He has
also talked to the insurance companies covering the races for Reno and
they also say they are not going to cancel their coverage of future
races. Now we wait for the FAA to make a decision.

[westhawk]

Interesting what Jackson has to say. I would ask whether this aft CG induced pitch instability was noted during practice and qualifying. If so, wouldn't it have been addressed? I would tend to think so, but I wasn't there and am not privy to what went on inside Jimmy's team. Maybe Matt is...

I'd also be interested in knowing more about the sound of the trim tab breakage on tape. Which tape? Was the microphone in the airplane or somewhere on the ground? I ask only because I want to confirm that the sound noted is time synced with the visual and telemetry data.

As for the rumors about NTSB recommendations and insurance company willingness to issue policies for future races, that's reassuring even if only a rumor. I hope it's true and that the FAA won't come up with ridiculous rules. I also hope the race haters in Lemon Valley don't gain any extra traction because of the crash.

[Mark1234]

Couple of thoughts wrt trim specifically.

I doubt there would be a working of the trim in the turns. In my humble aero experience, we generally trim for a fairly high speed, and accept the pull elsewhere. Main reason for this is that the human arm works pretty well at holding and measuring a pull, much less accurately a push. I would imagine this holds for the racers too.

WRT the tab's AOA, it's angle to the free airstream may be increased, but I would question whether it would see much real AOA change - it is hung on the back of a big plate (elevator), which is conditioning a very large part of it's airflow. Further, at those sort of speeds, I doubt there's very much angular movement of the elevator (if you see what I mean). I'm also rather unsure about an increase in 'pull' increasing the roll. You need to increase the roll to maintain level flight/avoid a climb yes, but I don't believe it is causitive. There may be some aerodynamic effect that causes this in theory, however in my experience if I'm hanging out at big bank angles and whale on the stick, it doesn't effect roll one bit.

WRT a trim failure - I suspect the issue is less the overall stick force required for level flight, but the transient. Imagine you're flying along with a slight pull on the stick, and suddenly the trim force is removed. The stick smacks back at you; even assuming perfect conditions, it will take you some time to react and recover equilibrium. This presumably is behind the (much) earlier reported comments from someone saying that they told the race pilots not to use trim. Now assume you've been pulling 4g for a few seconds, and the event suddenly smacks you into the 10+G regime.. Not hard to imagine the world going black before you get it sorted.

[Lyman]

I follow that. As seen, Leeward was pulling substantial g in the turn; acclimated to that, and pulling against trim to begin with, if it let go (the tab) the a/c would Pitch Up immediately, we saw VooDoo do that.

If the cg was too far aft, the a/c has a second instant problem, augmented climb. Additional Pitch UP. Since the a/c was wings vertical, the drop of the tail would cause wicked Yaw left. One g would express itself 'laterally' instead of 'vertically', relative to the airframe.

Turbulence? Causative? Hmmm. It may have been additive, but I doubt it was responsible. I'll go with it, if it helps politically. I think scrutiny of the Class will happen anyway, and we'll see 'improvements' in structures and policies? Regs?

Jackson himself let's the cat out anyway, describing the Ghost as 'unstable'. An entire lap of instability can't be down to wind. Is he some kind of "Spokesperson"? I'm just guessin' and readin'; sharper minds than mine will out.

[ClippedCub]

I'm not sure about the trim tab failure being the cause of the rolling moment because the turn did not appear to tighten.


Just as the aircraft was straightening out, he hit a second mountain of
turbulence which caused the tail to 'dig in' resulting in a 10+ G climb
rendering Leeward unconscious instantly and resulted in the tail wheel
falling out. (broken tail wheel support structure was found on the
course). As the Ghost shot upward the LH elevator trim tab broke loose.
This can be heard on the tape, so the trim tab did not cause the
accident.

Since the Ghost was racing at 480 mph with full right rudder and the
stick full right, this is where everything stayed when Leeward blacked
out.



If you look closely, you can see a sudden nose-up pitch while in the turn. But I've still not sure about the trim tab failure sequence causing the the rolling moment either, just leaning. The aircraft quit rolling at wings level, so the stick didn't stay over-to-the-right after the correction.

If I had to guess, Leeward felt the sudden pitch in the turn, knew what was coming from prior airplane tab scenarios, and went to wings level to give himself a chance. He was already clinced to counter the turn g, so when the g shot up, his current body configuration probably bought him another fraction of a second to react.


I would ask whether this aft CG induced pitch instability was noted during practice and qualifying.


They set the cg to what they are confortable with. Matt's reference to an overly aft cg is conjecture.


I doubt there would be a working of the trim in the turns.


They trim and go. Rarebear's the worse for stick force changes around the course. The Mustangs sticks are relatively light.


Instead of pointing out what's wrong with my statements, you suggest google and then ask if I am a pilot.


The answers to some of the statements are intuitive, generally basic and can be looked up. Didn't come here to school, since like most here, am still putting the pieces together. I haven't written you off, you have some good to contribute - like realizing that the seat bottom is under load and not the seat back.


Are you one? Really?



PPL. Still have the Cub I learned in at 16. Flew loops, rolls, ... in a stock Mustang as a treat. Ailerons and rudder gets stiff at speed. Soloed a T-6G. Currently own Yak-52, Chipmunk, Cubs, trainer types.


but I venture to say I have a bit more courtesy than you.


That's probably true. I try to write factually.


What are your thoughts re: trim? Need a picture?



Trim's untouched during the race. Pilot workload's enough, and it changes the airplane when you don't want it to change.

Somewhere in here, Penny talked about Rarebear trim. Ignore the stagnation point/ versus shock strength portion. That part's wrong.

Reno2009 National Championship Air Races John Penny and USAFA Cadets Part Two - YouTube

[Lyman]

"Trim is untouched during the race."

That too is conjecture.

In the slomo run, I pay close attention to AoA as the roll left stops. From the constant perspective of the camera, we start to see more and more of the belly, out of sync with turn rate. This indicates a Nose UP trend, at least to me. There is a flash of up left aileron in the right reversal, suggesting the pilot was not in control, but that the ailerons were driven by airstream, not stick. I don't conclude that the pilot had time enough to recover from the left roll, nor that he had time to Rudder. If there is this flash of Nose UP, I think the pilot was out instantly. This Pitch caught him and his upper body left of the stick, and he was forcibly slumped into the left space, inputting an inadvertent right roll.

Some maths genius should calculate the g in the video supplied by the 'wrench'. He got 500 feet in less than ? seconds. I doubt 21g, but math is not me.

Thanks greatly for the RareBear vid. Takes stones to call Penny "wrong".

You are a hardass..... :ok:

It isn't only up to skull oxygenation, as you know. G can be a full on haymaker from a very big fist. Acceleration of the skull can lights out the brain in milliseconds. Plenty of O2.

[Machinbird]

It isn't only up to skull oxygenation, as you know. G can be a full on haymaker from a very big fist. Acceleration of the skull can lights out the brain in milliseconds. Plenty of O2. That from the person without experience pulling g.:rolleyes:
We are not discussing direct impact to the skull. The Martin Baker back breaker used to give people an 18 g launch until the back injury statistics got out of line. Then they reduced the charge and added rocket motors to spread the impulse. But that 18 g kick did not put your lights out.

Lyman is well known from the AF447 threads, and his strengths appear to be in the legal direction rather than the aerodynamic ones, however he is not hesitant in trying to tell you his version of events, sometimes with fanciful additions.:hmm: I wouldn't absolutely discount his ideas, but instead examine them with a great deal of caution.

[skwinty]

Lyman (http://www.pprune.org/members/365757-lyman)

"Trim is untouched during the race."


That too is conjecture.Skilled pilots do not use trim to fly the aircraft.

The elevator trim is set for a specific pitch attitude and left like that until another specific pitch attitude is required.

It's one of the first lessons of flying.

[xmh53wrench]

I have been all over the net regarding this iincident, and have seen a bunch of locked threads please don't let this happen here. This thread is amazing, thanks for all the insight. That said, Lyman any new thoughts on the aileron swap? Clipped, r u leaning towards the tt failing in the turn? Thanks again you guys.

[Lyman]

It was Matt Jackson who accused Leeward of flying with trim, not an opinion of mine.

At 74 yoa, this pilot had just had `~50 square feet of wing chopped off, along with half his ailerons. As far as we know, he had maybe an hour on the airframe.

In this heat, he was cooking, he's passed RareBear, and his trim tab was costing him maybe 2-3 knots. He won't fly trim?

He needs a note from his Mom?

Machinbird. With a selected ejection, you have your spine, erm, organized.

In a hot little P-51, drooling for the gold heat, Mr. Leeward's noggin was ready for 10 g's? It didn't bounce off the plex like the nine ball on a break?

You assume too much, and you question too little.

[xmh53wrench]

Btw, listening to Penny, you pilots are the last gladiators....auto racing is childs play.....I feel so unworthy....lol

[ClippedCub]

There's another reason not to touch the trim. The pilot can monitor aircraft status during the race. If the airplane exhibits any pitch changes, or stick force changes, that would be an indication to the pilot that the airplane configuration has changed.


Lyman is well known from the AF447 threads, and his strengths appear to be in the legal direction rather than the aerodynamic ones, however he is not hesitant in trying to tell you his version of events, sometimes with fanciful additions.http://images.ibsrv.net/ibsrv/res/src:www.pprune.org/get/images/smilies/yeees.gif I wouldn't absolutely discount his ideas, but instead examine them with a great deal of caution.


Thanks for the heads up.
Lyman, you're requiring an emotional response and your posts, to me anyway, appear random, scattered with a lack of restraint, reduced self filtering, and now a lack of respect. Requires too much energy to find any worthy thought, and I don't have time to read your posts anymore so I'll be skipping over them. That also means I won't be responding to them. Nothing personal, there's room for all kinds of people in the world, I just choose who I communicate with whenever I can.

[deSitter]

"pilots are the last gladiators"

Oh please. Yuck.

-drl

[Machinbird]

Just as the aircraft was straightening out, he hit a second mountain of
turbulence which caused the tail to 'dig in' resulting in a 10+ G climb
rendering Leeward unconscious instantly and resulted in the tail wheel
falling out. (broken tail wheel support structure was found on the
course). As the Ghost shot upward the LH elevator trim tab broke loose.
This can be heard on the tape, so the trim tab did not cause the
accident. Not sure I'm entirely in agreement with this analysis. As I stated earlier, I think I'm seeing some differential movement of the elevators in one of the left bank event initiation videos. If correct, this implies a similar failure to the Voodoo Chile pitch up.
http://warbird.com/voodoo3.jpg
Looking at the Voodoo Chile picture of the tail after the event, the elevators are clearly pointing in different directions.

If you look at the elevator actuating bellcrank and a sample elevator, the most logical point of failure on Voodoo would be something like the 3 hole bracket on the end of the torque tube where it is riveted to the torque tube with what appears to be AN470 rivets
If the torque tube sheared outboard of that location, you would likely lose the entire elevator. since the center and outboard pivot points should fail sequentially if the inboard attachment is lost. The bracket collar would act to restrain the inboard end of the elevator torque tube if the rivets sheared.
http://i2.photobucket.com/albums/y17/msowsun/Airline/Clipboard02-1.jpg
http://home.comcast.net/%7Eshademaker/GhostElBellcrank.JPG

Does anyone here actually know where the elevators separated/sheared on Voodoo? :confused: Could shearing of torque tube rivets be an initiating event for what we saw happening on GG?

[The Old Fat One]

Given all the obvious talent commentating on here, I am somewhat shocked that this little gem alledgely attributable to the NTSB has not drawn comment...


Matt has had long conversations with the NTSB who call the accident a
'fluke'.


From my dictionary

Accident...

An unfortunate incident that happens unexpectedly and unintentionally

Fluke...

Unlikely chance occurrence

Not just semantics...I've never known an accident board to be the business of quantifying the part that lady luck has played in each and every accident (aviation or otherwise) since the dawn of time. I thought accident boards existed for the purpose of human enlightenment and such applications as the management of risk?

That statement could easily be construed as " sh1t happens...move on". Nothing wrong with that as a (somewhat unsophisticated) philosophy..but I hope the guy making that statement is not drawing a very large salary.

[ClippedCub]

Does anyone here actually know where the elevators separated/sheared on Voodoo? http://images.ibsrv.net/ibsrv/res/src:www.pprune.org/get/images/smilies/confused.gif

From what I understand, the torque tube sheared the retaining fasteners, whether at the pictured housing or internal to the elevator. They assumed the tab actuator rod failed from fatigue.


Could shearing of torque tube rivets be an initiating event for what we saw happening on GG?


Could be a likely event considering the single tab configuration, though the opposite elevator attachment would have been the side that failed. In the Voodoo case, after departure of the tab, the elevator would become more overbalanced.

Found some g vs aging data, turns out we're pretty wimpy when we're young.

(http://lib.bioinfo.pl/pmid:711580)Relaxed +GZ tolerance in healthy men: effect of age. (http://lib.bioinfo.pl/pmid:711580)
[My paper] (http://lib.bioinfo.pl/pmid:711580)D H Hull (http://lib.bioinfo.pl/auth:Hull,DH), (http://lib.bioinfo.pl/pmid:711580)R A Wolthuis (http://lib.bioinfo.pl/auth:Wolthuis,RA), (http://lib.bioinfo.pl/pmid:711580)K K Gillingham (http://lib.bioinfo.pl/auth:Gillingham,KK), (http://lib.bioinfo.pl/pmid:711580)J H Triebwasser (http://lib.bioinfo.pl/auth:Triebwasser,JH)

Fifty-three healthy US Air Force aircrewmen, 26-55 yr old, volunteered for a centrifuge study designed to determine the effect of age on relaxed +GZ tolerance. Each was subjected to G forces of gradual and rapid onset, with G tolerance determined by standardized contraction of peripheral visual fields. Of the subject characteristics studied, only age was positively correlated with rapid-onset G tolerance; both age and weight were positively correlated with gradual-onset G tolerance. A combination of age and weight gave a stronger positive correlation with G tolerance (rapid- and gradual-onset) than did either characteristic alone. No significant negative correlations were observed. We conclude that aging may offer some protection from G stress; there is no evidence that aging leads to a decrement in G tolerance.
(http://lib.bioinfo.pl/pmid:711580)

G-induced loss of consciousness: case-control study of 78 G-Locs in the F-15, F-16, and A-10. (http://lib.bioinfo.pl/pmid:15828637)
[My paper] Nereyda L Sevilla (http://sevilla.nl.lib.bioinfo.pl/auth:Sevilla,NL), John W Gardner (http://gardner.jw.lib.bioinfo.pl/auth:Gardner,JW)
Department of Preventive Medicine, Uniformed Services University of the Health Sciences, Bethesda, MD, USA. [email protected]
INTRODUCTION: This study determined the trends of reported G-induced loss of consciousness (G-LOC) mishaps from 1980--1999, and determined potential risk factors in pilot characteristics; specifically, 30/60/ 90-h and sortie history, total flight hours, total hours in the aircraft, age, height, weight, and BMI. METHODS: Using aircraft malfunction mishaps to reflect a cross-section of USAF pilots, potential risk factors were determined using a case-control method; cases were all G-LOC mishaps and controls were aircraft malfunction mishaps. The data consisted of 2002 mishap pilots in the history of the F-16, F-15, F-15E, and A-10 from 1980-1999. RESULTS: During this time, G-LOCs represented only 2.5% of all mishaps. The mean engagement number for G-LOC mishaps was three at an average of 8 Gs. A poor anti-G straining maneuver was cited in 72% of the mishaps, fatigue and G-suit malfunction in 19%, low G-tolerance at 14%, and 37% were student pilots. Within pilot characteristics, only two factors were found to be statistically significant: the time in the aircraft and pilot age. In the F-16, there was a 3.5 times greater chance of experiencing a G-LOC mishap if the pilot had less than 600 h in the aircraft [3.5 (1.7-7.2, 95%CI)], and a 9.5 times greater chance in the F-15 [9.5 (2.2-41.9, 95%CI)]. There was a 4.5 times greater chance of experiencing a G-LOC mishap if under the age of 30 in the F-16 [4.5 (2.3-8.5, 95% CI)] and a 3 times greater chance in the F-15 [2.8 (1.2-6.8, 95% CI)]. DISCUSSION: Though it is difficult to predict who will experience G-LOC, emphasis on prevention must be concentrated in training and in pilots new to the aircraft.

[Lyman]

If the elevators had lost continuity along their hinge line, that should leave one operating, and one in trail. Since the assembly (gross) seems to have survived a potential fracture, there could have simply been a misalignment between the two, as shown in your pic of VooDoo. Had there been an actual separation at the bell crank center, the elevators would have shown some level of partition in the video, I think.

The design of this system shows an obvious plan for symmetrical Stress.

From a design standpoint, had there been a desire to allow differential forces on each elevator, the Torque Tube would have been one piece, not halves. The bell horn would have been halved, and surrounded the tube, in clam shell, or other, perhaps splines, allowing for erm, Torque.

Defeating this design (disabling trim on one side) appears to have some drawbacks in operation.

Machinbird's catch on VooDoo shows a greater up load on the left elevator, consistent with carrying chronic ND trim with only one elevator.

Nitpick. The picture of the elevator with tab on the bench is of the Ghost, not VooDoo. The image signature is "Scott Germain" proprietary to GG. So, we do not know the method of attachment of the tube to the retainer/cup on VooDoo. Likewise, the "Rivets" might be bolts; The join carries such stress, aluminum fasteners seem wrong.

Old Fat One. Absolutely, that word was not NTSB-ish. It was probably Jackson's. In American, "Fluke" means "Next to impossible" and "unrelated to responsibility". The only way to convey more innocence would be to call it an "Act of God".

[Sir George Cayley]

I've heard about something called 'stick free neutral point'. If the CofG was aft and fuel was being used from the wings, could the rearward moment arm have contributed to this condition?

SGC

[Lyman]

Sir George.

The engine is cooled with 'evaporative cooling'; as the coolant evaporates, it is vented out, and lost. So there would be a loss of mass associated with cg also? I believe the evaporative cooler is behind the cockpit, so would this serve to improve the aft cg? Assuming there is always liquid to cool the engine, the mass of the coolant (Water/Methanol) would diminish from behind cg?

[ClippedCub]

I've heard about something called 'stick free neutral point'. If the CofG was aft and fuel was being used from the wings, could the rearward moment arm have contributed to this condition?

The racers have played around with ballast, they know their cg vs consumables loading chart, and they set the cg to what they can handle throughout the race. Leeward had GG flying for a few years so wouldn't think he'd be pushing that on a Friday, though anything's possible. He did demonstrate he could handle the airplane for 3 laps, so he felt comfortable enough to continue.

The problem though is that he required a lot of trim to get the stick force managable. The one trim tab did double duty and is a significant departure from the original design. They would have tested this configuration to Vdive at altitude, but the dynamic pressure is a lot lower up high as opposed to the 5,100 ft race altitude, and the test would have been done at 1 g.

In terms of stick-free stability, I've included a simple pdf explanation without the eye glossing equations.

www.flightlab.net/Flightlab.../5_LongitudinalStatic%232BA158.pdf

Intend to go back to the video to visualize a new failure sequence with the starboard elevator shearing and going stick free on that side. This would assume turbulence causing the left roll disturbance and top rudder and stick forward and to the right as recovery inputs. They're briefed, as if Leeward wouldn't already know, to fly those inputs when they find themselves even slightly inverted.

In the turn, the shock wave on the wing moves the N.P. aft and increases stability. That shock induced increase in stability goes away under 1 g.

[Lyman]

With the Pitch Up at wings vertical after the snap left, I'd assume the elevators did not shear, for if one did, Pitch authority would diminish, and the Pitch Up would stop. Then again, having one elevator inop at the start of the right reversal, would explain the wicked Torsion visible in the tail (video).

[stressmerchant]

From ClippedCub
They would have tested this configuration to Vdive at altitude, but the dynamic pressure is a lot lower up high as opposed to the 5,100 ft race altitude, and the test would have been done at 1 g.
Speeds such as VD are specified as Equivalent AirSpeeds in the standards - hence altitude should not be an issue. The exception is when mach number is a limit - MD rather than VD.

Was this aircraft actually tested to a declared VD?

As a matter of interest, does anyone know to what extent these aircraft are tested against standards? As an experimental aircraft they are obviously not expected to meet all standards (eg FAR23), but is there a set of minimums that are applied?

[Lyman]

That is a terrific question.

If there are Standards, there have to be predecessors, How does Burt Rutan make a living? Some one has to be first?

Experimental?

Who would allow asymmetrical Tab stress? Who will disallow it? Frankly, how much power does RAR have?

[ClippedCub]

Speeds such as VD are specified as Equivalent AirSpeeds in the standards - hence altitude should not be an issue. The exception is when mach number is a limit - MD rather than VD.

Trying to keep it simple. MD is 0.80. VD is 505 IAS at race altitude and up to a certain altitude that I forget.

Was this aircraft actually tested to a declared VD?

The teams have competent structural engineers from industry and the owners listen to them. If they required a test, they would have gotten it. They would have corrected to VEAS where they could, but doubt they would have done it at 3-5 g's. There's a perception that the airplanes are being pushed beyond the original design limits, but the Mustang guys honor the 505 IAS limit, and frankly they're having a hard time getting there. Though there might be some truth in that since the 505 IAS limit wasn't established at 3-5 g to begin with.

As a matter of interest, does anyone know to what extent these aircraft are tested against standards? As an experimental aircraft they are obviously not expected to meet all standards (eg FAR23), but is there a set of minimums that are applied?

They're licensed in the eperimental catagory, maybe experimental/exhibition. Don't think they're restricted. Basically means you can do what you want as long as the hardware is airworthy and is signed off by the mechanics. The teams I contacted about mods were very concerned about safety, and we convinced ourselves we had the same level of concern when it came to modifying the airplane, i.e., I was originally concerned they might slap something on and go fly at Reno, and they assured me they wouldn't. In this sense, think the FAA is/was comfortable with owner's getting with the profesionals for any mod program.

[Machinbird]

Lyman, fair question, I'll attempt to answer.
Who would allow asymmetrical Tab stress? Who will disallow it?There are many examples of light aircraft with asymmetrical trim tabs. The concept in itself is not the problem. The application of the concept to an experimental aircraft such as GG would be an issue if complete engineering and testing was not done before adopting that design.
My understanding of the regulations affecting experimental aircraft is as follows:
(Feel free to shoot me down if I'm wrong." )

As a US based experimental aircraft, construction merely needs to be performed in a workmanlike manner and to survive a certain amount of flight time before being permitted to be flown out of the designated test area. The regulations recognize that experimental aircraft may experience unexpected events and kill the 'test' pilot. The idea is to minimize the potential for for injury to others if the worst happens.

The problem with experimental aircraft is that the test program may not evaluate the full potential aircraft envelope. In the case of air racing, it is entirely possible to be exploring new ground during a race.

[Lyman]

Thanks Machinbird. It makes sense to me. I saw Red Baron with Steve Hinton and its six blades chopping up the air I think it was '80.

I did not see LearFang, but saw Rare Bear with Lyle Shelton in it when it was wide winged and all Navy Blue. I think Strega was all Red at one time, and forget the name of the lime colored P-51.

Hinton's Engine seized, and the props stopped just as he was about to land after a Mayday. He impacted over the hill on (near) 08 and the plume of black smoke was visible for five minutes before the announcer said he'd died. There was absolute quiet, it was near the end of the day, and everyone walked to their cars in disbelief.

He survived. These guys are a breed apart, and they take monster risks.
I've been to the show at Reno dozens of times. It doesn't get old.

There is something about a half dozen unlimiteds with 18000 horsepower that touches ones soul. Charging down the start, everything vibrates.

I fon't know who said it first, but it's rumored to be Lyle Shelton.
"What do you do at Reno, Sir?"

"We turn money into noise".

[stressmerchant]

Trying to keep it simple. MD is 0.80. VD is 505 IAS at race altitude and up to a certain altitude that I forget.
ClippedCub, is the VD / MD limit specified by the contest rules?

[Brian Abraham]

Extract of LurkerBelow post
Matt believes the cause of the crash was due to The Galloping Ghost having a CG too close to the aft limit which resulted in pitch instability.

During qualifying Matt watched Galloping Ghost from inside the cockpit of Furias and could not believe how much trouble Leeward was having in keeping the Ghost in a stable pattern around the course.Thus far people have been concentrating on the trim tab as the initiator of events, where as perhaps its failure was a consequence of events, as with the extension of the tail wheel and the loss of its gear doors.

It's understandable why a racer would want the CofG as far aft as possible - less drag and hence more speed. How far aft is aft enough though?

As airspeed varies from a trimmed condition, the column force required to maintain a new speed (without re-trimming) is a measure of static longitudinal stability. For any conventional airplane, the location of the CG has the strongest influence on static longitudinal stability. For a statically stable airplane the required column force, as speed varies from the trimmed condition, is less at an aft CG than it is at a forward CG. As the CG moves aft, it reaches a point where the stick force per knot drops to zero, then reverses. This location is called the neutral point. The difference between the actual CG location and the neutral point is called the static margin. With a CG forward of the neutral point, an airplane has a positive static margin and positive static longitudinal stability. At a CG aft of the neutral point, an airplane has a negative static margin, is statically unstable, and may require some form of augmentation (computers) to be flown with an acceptable workload eg relaxed stability fighters F-16.

The result of moderate instability might be a flyable aircraft, but the workload goes up. If you pulled back on the stick the aircraft will pitch up and slow. But if you let go of the stick the nose will continue to pitch up, since a positive pitching moment will remain. It will require a push force to maintain a climb angle, not the mandated pull. If you pitched down and let go, the nose will tend to tuck under. You’d have to apply a pull force to hold your dive angle, not the mandated push. That’s how the Spirit of St. Louis behaved.

Manoeuvring stability, like static stability, is influenced by CofG location. However, when the CofG is aft and near the neutral point, then altitude also has a significant effect. Since air density has a notable impact on the damping moment of the horizontal tail, higher pitch rates will result for the same elevator deflections as altitude increases. From the pilots perspective, as altitude increases, a pull force will result in a larger change in pitch angle, which translates into an increasing angle of attack and g. While a well-designed flight control system, either mechanical or electronic, will reduce the variation of stick force with CofG and altitude, it is very difficult to completely eliminate the variation due to design limitations.

For example, for the same control surface movement at constant airspeed, an aircraft at 5,000 ft experiences a higher pitch rate than an aircraft at sea level because there is less aerodynamic damping. The pitch rate is higher, but the resulting change in flight path is not. Therefore, the change in angle of attack is greater, creating more lift and more g. If the control system is designed to provide a fixed ratio of control column force to elevator deflection, it will take less column force to generate the same g as altitude increases. What was the DA at Reno at the time?

Note the increased work load. Matt is quoted as observing Leeward having difficulty flying the course. High work load due aft CofG? Perhaps the workload just got too much and the aircraft caught him out. Time will tell.

Even the experts can get the CofG wrong. An SR-71 was lost on a test flight when the aircraft pitched up uncontrollably and disintegrated. The initiating event was an unstart, but the loss of control was the result of having the CofG too far aft.

[ClippedCub]

ClippedCub, is the VD / MD limit specified by the contest rules?

Doubt it. Never looked at the rules. What I was trying to do was increase drag divergence Mach number, specify the flight testing required to make me feel comfortable, which would have included VD, and left it up to the teams to determine conformity if any rules were pressed.

Hinton's Engine seized, and the props stopped just as he was about to land after a Mayday. He impacted over the hill on (near) 08 and the plume of black smoke was visible for five minutes before the announcer said he'd died. There was absolute quiet, it was near the end of the day, and everyone walked to their cars in disbelief.

Lyman. Goofed and read your post by accident. Didn't realize you were one of us. We've been having some trouble with kids-in-mom's-basement on a financial board I frequent and I was sensitive to elaboration. I'll write you back in if that's ok.:ok:

[ClippedCub]

Even the experts can get the CofG wrong.

There's always room for error, but if Leeward felt uncomfortable, he would have aborted. His stability would have increased in the turn after he poured on the coals to make the pass. It would have been more pitch sensitive when he was unloaded.

[ClippedCub]

Corrected link from before on stability.

http://flightlab.net/Flightlab.net/Download_Course_Notes_files/5_LongitudinalStatic%232BA158.pdf

[stressmerchant]

ClippedCub, any idea if they are forming shocks on the tail at this speed?

And what balance limits do they use of the elevator? Original P51 figures?

[ClippedCub]

ClippedCub, any idea if they are forming shocks on the tail at this speed?

And what balance limits do they use of the elevator? Original P51 figures?

Was going to keep this to myself so as not to clutter up the discussion, but the elevator has been reshaped for high speed effectiveness. It's more bulbous. This is to get it out of the boundary layer of the horizontal stabilizer and would have been selected by his aero guys. There is a basis for this from the old NACA reports that I was going to dig through again, but if a shock did form, it will form on the deflected elevator itself and not on the hinge line or ahead.

The tail is at a much lower thickness-to-chord than the wing, so the tail wouldn't have a shock. But shock waves are sensitive to curvature too, and the bulbous elevator will cause a re-accleration of the flow. Doubt there was a shock here, but in the interest of thoroughness, it's on my list to check, if for nothing else, to determine the margin.

Don't know anything about the balance specs, but it's not unusual for the guys do flutter flight tests when needed.

[stressmerchant]

the elevator has been reshaped for high speed effectiveness. It's more bulbous. This is to get it out of the boundary layer of the horizontal stabilizer and would have been selected by his aero guys. There is a basis for this from the old NACA reports that I was going to dig through again, but if a shock did form, it will form on the deflected elevator itself and not on the hinge line or ahead.
Very interesting, thanks for that. Any idea why they felt the change necessary? Were they running into a (stick force) stability issue?

[Lyman]

You're writing me 'back in'? Was I out? :ok:

cheers

[ClippedCub]

Very interesting, thanks for that. Any idea why they felt the change necessary? Were they running into a (stick force) stability issue?

There was a lot dive testing going on around the war and they played with shapes to affect the hinge moments and effectiveness. The technology development ended when the Brits figured out the flying tail. GG looks more bulbous, but it could be an illusion from the squared tip, or a later model elevator. I'll be around a stock D model next month and I'll look then.

Wasn't going to bring it up. Think we can figure out the failure sequence collectively without referencing that detail. If we couldn't, was going to spend time looking into the elevator shape, and maybe shock bursting on the wing if the speed and g warranted.

[sycamore]

CC, in #251 here there is a link to `hangartalk`,air racing; if on that link you go back to page9 #88 there are 3 photos which show the `oil-canning and the tab deflection from the rear quarter.(if you haven`t seen them already).
The Mustang 4 was limited to 505 MPH or .75 M,but had probably been flown faster in testing.Also the aircraft in those times had fabric covered elevators and wooden or plastic trim tabs and one on each elevator would reduce the loading,fabric covered surfaces tend to distort aerofoil shapes at high speed; later they were made all metal,except the rudder.Since GG is a `racer` the rudder tab is also faired in.
It would be interesting to know if the stbd.tab on GG was `locked` to the elevator,or to the tailplane as a balance tab,to reduce stick forces.
With regard to the `over-bank` at pylon 8, I would consider that to be gust induced,either by the preceding two aircraft and/or natural wind,which may have caused and been sensed by JL as a possible change to his `line` around 8,and preventing a possible `cut`,requiring a quick push,and a bit of roll-out.
It is difficult to see the pylon and aircraft to draw a reference as to how close he was now running,after having passed the `Bear`,and flying a wider pattern to do so.It is a lot harder to run closer to the pylons,with a lot more activity on the controls to get a tighter line.
With regard to the roll, I think that was induced by precession from the prop on the pull-up,causing roll,as the controls have become free,and as the aircraft starts downhill,it will try to go to a trim speed,controls free again.

On another subject,I have searched for the NTSB archive for the definitive results of the investigation into the tail failure of Miss Ashley` in `99`,but only find the standard report,which give no real structural results..Anyone got anything more definitive..?

PS.GG was reported at 495 mph; that equates to M.645 at 5500ft at an assumed *T of 20*C; M.75 would be 579 mph in the same conditions.

[ClippedCub]

Other P-51 racers are saying the oil canning is normal, and transitory, though I'd think they'd eliminate that from a drag standpoint since they're meticulous on maintaining smoothness. The deflection of the port tab with the strbd in trail caught my eye as an engineer.

Placard is 0.75M, but they've tested to 0.85M where the Mach buffet shakes the scoop loose and causes rivets to pop. The aircraft was unairworthy on return. As such, MD will be 0.75M as opposed to the 0.80M Mach misspeak from earlier. This would mean demonstrating the Reno q's during the dive test would have been more unlikely even using an adjusted VEAS for 5,000 ft instead of SL. The structural engineers would have compensated to 5,000 ft q's, but it wouldn't have been demonstrated.

The conversion to metal from fabric was to limit the PIO on dive recovery at high Mach numbers for reason you've noted.

Currently the quick push, post left roll you noted, would have further increased the loads on the right elevator and that might have been what did it. The pitch change occurs immediately after the left roll. This would assume a natural disturbance to cause the roll.

Loads weren't understood as well in the forty's so the engineers overbiult everything. That's why DC-3's are still in service, and the reason these airplanes are lasting so long. But the tails are getting beaten up from the horsepower increase to 4,000 and they are in direct influence of the vibrations caused by the blade pass frequency, and are getting bombarded by the blade tip vortices.

Yak-52 Prop Vortices - YouTube

Going to a single tab will put undue loads on the tab free side, and maybe it all just added up. Or the tab actuator rod just had enough since it was supporting double the load.

[ClippedCub]

PS.GG was reported at 495 mph; that equates to M.645 at 5500ft at an assumed *T of 20*C; M.75 would be 579 mph in the same conditions. A little slow for a strong shock wave to form unless he was pulling significantly more than normal turn g. But again, add in the Mach buffet during testing, and the tab rod or attachments could have been fatigued.

Shock strength and location are dependent on Mach number and CL. You can see what Mach buffet looks like from the tufts and the wake rake/camera vibrating. Mach buffet is just a stall, but at substantially higher q's so the loads are higher.

XP-51 Stall Studies - YouTube

[fernytickles]

More fundraising for the victims of the crash going on at the moment....

loadedtv - live streaming video powered by Livestream (http://www.livestream.com/loadedtv)

The goal is $1,000,000 - nothing ventured, nothing gained :ok:

[deSitter]

You are taking an airplane designed to kill Germans with 1940 engines. Because it's a cool airplane, let's race it by chopping it to s--t and tearing off its radiator and on and on.. stupid and hateful.

The pilot and his crew blasted several people into atoms with their insane modifications of this airplane, and their old man steward who dyed his gray hair brown, because the idea of graceful aging was anathema to his narcissist being, is the main culprit.

This entire episode is hateful to aviation - the butchering of a great airplane, the narcissism of the pilot, the tragedy of the annihilated and their families. For what? A stupid race that means nothing. A way to convert money into noise.

-drl

[rh200]

This entire episode is hateful to aviation - the butchering of a great airplane, the narcissism of the pilot, the tragedy of the annihilated and their families. For what? A stupid race that means nothing. A way to convert money into noise.

Guess that's one way to look at it.:(

[Machinbird]

I've grabbed a bunch of video frames from the best video I've seen of the GG initial roll left. These have been processed by increasing brightness and contrast, and cropping to show only the aircraft. They seem to show the port elevator deflected up. The elevators are not visible at the initiation of the problem but soon become visible as the g turns the aircraft. Compare the thickness of the stabilizer-elevator combination above and below the fuselage to see this.
http://home.comcast.net/~shademaker/GG11.jpghttp://home.comcast.net/~shademaker/GG12.jpghttp://home.comcast.net/~shademaker/GG13.jpghttp://home.comcast.net/~shademaker/GG14.jpg

The only way that there would be significant elevator split is if the elevator torque tube system failed.
The third and fourth pictures appear to be showing the port elevator deflected upward. The second picture is not clear enough, and the attitude in the first picture puts the elevator too close to the wing to be sure of anything. Subsequent pictures appear to show the elevators back in balance.

One would assume that if the torque tube simply failed at either the port or starboard side, that the port elevator would be deflected downward by a force twice what was needed from the tab, and the starboard elevator would move upward due to the loss of down torque from the other side. Instead we appear to see the opposite effect, so perhaps the likely shearing of the torque tube is indeed due to a failure of the tab system.

The Ghost should have had an elevator bobweight in the system to increase stick force per g. If so, the mass of the elevator actuation system would act to dampen torsional shock loads being sent from the port elevator, so the torque on the inboard side of the port elevator could be higher than the torque on the inboard side of the starboard elevator.

The pictures of the trim tab separating indicate that the entire tab was not lost, but that it instead detached at the inboard end and broke off at the center support. The separation at the inboard tab attachment may be due to flutter from some other initial failure (such as the linkage), or it may be the actual initiating event.

[Brian Abraham]

Just thumbing through one of, if not the best book, on aerodynamics written and found this. (Aerodynamics for Naval Aviators)
PILOT INDUCED OSCILLATIONS

The pilot may purposely induce various motions to the aircraft by the action of the controls. In addition, certain undesirable motions may occur due to inadvertent action on the controls. The most important condition exists with the short period longitudinal motion of the airplane where pilot-control system response lag can produce an unstable oscillation. The coupling possible in the pilot—control system-aircraft combination is most certainly capable of producing damaging flight loads and loss of control of the aircraft.

When the normal human response lag and control system lag are coupled with the airplane motion, inadvertent control reactions by the pilot may furnish a negative damping to the oscillatory motion and dynamic instability exists. Since the short period motion is of relatively high frequency, the amplitude of the pitching oscillation can reach dangerous proportions in an unbelievably short time.

When the pilot induced oscillation is encountered, the most effective solution is an immediate release of the controls. Any attempt to forcibly damp the oscillation simply continues the excitation and amplifies the oscillation. Freeing the controls removes the unstable (but inadvertent) excitation and allows the airplane to recover by virtue of its inherent dynamic stability.

The pilot induced oscillation is most likely under certain conditions. Most obvious is the case of the pilot unfamiliar with the "feel" of the airplane and likely to over control or have excessive response lag. High speed flight at low altitude (high q) is most likely to provide low stick-force gradients and periods of oscillation which coincide with the pilot- control system response lag. Also, the high q flight condition provides the aerodynamic capability for failing flight loads during the oscillation.

If a pilot induced oscillation is encountered the pilot must rely on the inherent dynamic stability of the aircraft and immediately release the controls. If the unstable excitation is continued, dangerous oscillation amplitudes will develop in a very short time. If I'm not mistaken the accident ticks all the boxes, but as I commented before, time will tell. No taking over from the NTSB for me.

[Pilot DAR]

A way to convert money into noise.

... and jobs, and entertainment for many who pay, in doing so support a local economy, and technological improvements, and other benefits I'm sure....

Oh yeah, and give rise to many interesting and informative discussions (both in success, and unfortunate failure), some of which are intruded by persons offering no value or interest whatsoever, just foul drivel!

I'm sure there is great sadness with many people about this. Words like "kill" and "hateful" do nothing to help anyone get past this sadness. Perhaps deSitter should only type into computers which are not operating at the time....

On the positive side, I'm learning lots about control and stability! Thanks everyone else......

[fernytickles]

their old man steward who dyed his gray hair brown,...... is the main culprit

Finally, god's gift to aircraft accident investigation has worked out the cause of this very sad accident :rolleyes: Everyone else can relax now....

[Lyman]

Machinbird. I notice two additional artifacts: One, the port stabiliser makes a different line with the TE of the wing than does the Stbd. This shows a torsion to the right, out of rig with the Long axis? Also, one can see quite clearly the outline of the main spar in the wing. It is outlined by the skin taking form around it in reaction to the immense g.

[Machinbird]

the port stabiliser makes a different line with the TE of the wing than does the Stbd.Lyman, in which of the 4 pictures posted do you see this?
Take powerpoint and mark up the picture you think this is most obvious.
Be sure you are not looking along the trailing edge line of the elevators. You have to look at the leading edge of the stabilizer to show actual tail twist relative to the wing, probably by lining up the corners of the stabilizer LE tips.
If the port elevator deflected as much as I suspect it did, it may account for the left roll at the beginning.

[Lyman]

Hi Machinbird. It is most pronounced in the second frame. Line up the port stab with the dihedral of the (left) wing. Do the same with the stbd stab and note what I think is about 7-10 degrees off rig. Leftward. A straightedge makes it look sharper. The first frame shows it also with the Port Stab tip proud of the wing line; the stabd is blended in.

Rotate the frame 90 degrees, it is of course easier to see that way. The fourth frame would be about where I see a start of the recoil of the tail feathers back to stabd in slomo.

If one was patient, and could orient the PITCH angle with the video, and index it with the time between frames, a rough value of G could be had?

Do you notice the Spar shadow spanwise?

These are not inconsequential interruptions of airframe contour/rigging.

Imagine trying to fly or recover with the tail out of rig several degrees from the fuselage and wings.

Or don't, gives me the willies........:ok:

[Machinbird]

Lyman, I think you are being fooled by asymmetric elevator deflection into perceiving the stabilizer is twisted.

On the first picture, you cannot make out any stabilizer landmarks, only elevator. On the second picture, the light gap between the stabilizer and wing is symmetric although extremely small. On the third and fourth frames, the light gap appears symmetric.

Keep in mind we are dealing with very few pixels, and if you blow the pictures up to gain accuracy, the surfaces become 'mushy' and ill-defined.

Furthermore the display appears to begin shading in the next frame over a short interval and you have the beginning of the next image ghosting next to the current ones. This ghost effect isn't all bad since the degree of displacement of the ghost is an indication of rate of position change.

[ClippedCub]

From this video;

Reno Crash Live 2011-09-16 - YouTube (http://www.youtube.com/watch?feature=player_embedded&v=Ha95cl2gvPI)

If anybody can work out pitch rate for the first 45 degrees and the last 45 degrees of pitch, we can work out g. Might need a stop watch after correlating to the video clock. I got 90 degrees in 2 seconds but that's rounded from the video. Even then, works out to 16-20 g's average. Makes sense that Voodoo pulled 10g with one tab intact that GG would pull 20 g's with the only trimming tab displaced. If we can get tenths of a second, the number will be more accurate.

Torquing across the elevators due to the one tab is still bothersome, and a failure mode could be either elevator twisted loose from the torque tube exciting the 180 degrees out of phase plunging flutter of the horizontal that might be seen in the video. This would over strain the tab actuator rod causing the tab to flutter/fail allowing a higher g pitch up than Voodoo.

[trashie]

From a colleague in the US
Subject: Fwd: [GSWarbirds] Reno Incident



So here is the scoop I got over the weekend. Turns out one of the
mechanics at the airport was on the ground team for one of the unlimited
racers and had the spot in the pits right next to the lost plane. The
ground team had a real time data feed from the airplane.

Looks like the plane had a high speed flutter on the port elevator trim
tab. The pilot reported a vibration.

· The trim tab came off in flight which caused the entire tail group
to twist. There are trim tabs on both sides and the asymmetry caused a
huge over load. Also high power settings require a lot of nose down trim
to stay level, the loss of the trim tab could not be overcome by the
pilot. The twist in the tail group made the tendency to nose up even
greater and caused damage to the internal structure in the tail –
looking at the pictures you will see the tail wheel is down and the gear
doors are gone – stuff was coming apart in there.
· The twist and the loss of trim caused a near instantaneous 11G pull
up – this probably incapacitated the 73 year old pilot and may even
have broken the mounts on the pilot seat. Note you cannot see him in the
cockpit. The 11G pull also caused a brief loss of engine power from low
fuel pressure – the pump could not overcome 11G.
· After the 11G pull up the airplane unloaded in steep climb –
with the G off the engine regained power.
· Without the pilot to overcome it the airplane torque rolled causing
a split S into the ground.
· The data showed that the airplane was pulling 105 inches on
manifold pressure on impact. The "normal" race boost would be 60
to 70. So the airplane was going just under 500MPH when it hit so no
fire just total disintegration.

[ClippedCub]

Internet article of Matt Jackson denying previous internet article.

What Didn’t Cause the Reno Air Race Crash | Jeff Wise (http://jeffwise.net/2011/10/10/what-didnt-cause-the-reno-air-race-crash/)

[thcrozier]

"So here is the scoop I got over the weekend. Turns out one of the
mechanics at the airport was on the ground team for one of the unlimited
racers and had the spot in the pits right next to the lost plane. The
ground team had a real time data feed from the airplane."

Scoop of what? :8

Sorry but my daughter brought her iPad home and I had to try it out somewhere. No disrespect intended.

I've been following this thread since the accident and have learned a lot. The dynamics of racing, both human and Physical, are something of which I was previously unaware.

CC you've shown me what I should have been studying 35 years ago.

[ClippedCub]

Another frame showing bent port HS due to plunging flutter if the frame isn't an optical illusion. The counterweights out at the tips would exacerbate this mode from the elevator pitch flutter, and/or an elevator twisting off the torque tube. The left one looks a little bent too.

http://www.wire-edm.com/temp/1.jpg

[Lyman]

Machinbird. You are saying that asymmetric elevator has me fooled into seeing the stabilizer is twisted? What else could it be doing? Any out of consonant deflection by the two elevators would torque the Stabs radically. At that velocity? It would twist the airframe, I don't see ailerons capable of rolling that a/c that rapidly, the roll was uncommanded, surely.

I do see the twist of the tail, and I see the a/c recovering from it in the video. The recoil shakes the image of the a/c in the video, do you not see that? There is distortion of the image throughout this sequence, the object was in the midst of a violent airborne prang. imo.

Cub: Yes, The left HS has a pronounced anhedral in that image.

That appears to be Mach's #2 image in his four sequence panel, above.

If I may, I'd suggest I see the ailerons commanding a right roll in that image, and we know it was rolling left. Did the tab problem interrupt a right roll?

[thcrozier]

Frame 2 appears to me to show the ailerons commanding a right roll as well, but because the plane had moved some distance between 2 and 3, the camera angle, including a possible roll off vertical of the focal plane itself, might have occurred within that interval. Spherical aberration in the lens might also be coming into play. Therefore, I wouldn't bet a whole lot of money that the plane is really banked more steeply left in Frame 3 than it is in frame 2. I'd want to know much more about the camera and lens before opining on what frame intervals show. You might even need multiple angles to be sure; though telemetry could well render optics issues moot at the end of the investigation.

I agree that there appears to be significantly more downward force on the left side HS than on the right in Frame 2; so his initial roll rate to the right could have been slower than he expected. Was he really going for horizontal wings, which, if still conscious at the time, he would have known would send him straight over the crowd, or is it possibly over control or an unpredicted snap to the right that put him there?

[Lyman]

I think the right elevator may have failed at its mount to the bellcrank before the tab failed. If it retreated upward, this leaves the left elevator to command the current NOSE DOWN. It cannot, on its own, so it loses the trim tab, and both elevators migrate to emphatic NOSE UP, though asymmetrically. I'd like to be able to say Jimmy immediately pushed and rolled right, but I think he was already incapacitated. I think with maximum tail section deflection down, and twisted port down, the a/c violently reacted, and pitched back on its own to ND and level, carrying right aileron throughout the double fail. The tail section reverted to close to original alignment, but, carrying some NOSE UP bias, the a/c climbed, lost power, and ballistic roll, inversion, and power recovery followed.

It's hard to say. I am astonished with the violence of the Pitch Up with wings vertical, and believe this is the point of maximum airframe load.

The fact remains that NTSB have it all. All of it. They will have the real deal in time enough. Without risk, and bold experiment, life would not be full.

I'll be at RENO next year; maybe I'll get to meet up with Clipped Cub.

[sycamore]

Been looking for information on whether trim tabs should be mass balanced,but could not find anything conclusive; however if one `googles `SAWE`Paper3020`,by Space Electronics,there is good stuff about mass balance and the effects of `flutter`.
I have had aileron flutter on an aircraft,coincidentally an 80% scale Mustang;on completion of some testing for `G` limits and `rolling `g`pull-outs.It started at about 160kts,as I was doing a little `flypast` for the owner at an airfield at about 3-400ft.It sounded like a `Gatling` gun firing,and looking at the left wing I could not see it,the right was quite steady.Vibration was also quite severe,and I had to climb,reduce power almost to the stall to stop it.After landing, the aileron bellcrank and pushrod were found to be sheared .Also,although made to specification ,there was insufficient mass-balance on the ailerons.The wings were wooden,and stressed to +-12 g,but I`m sure if they had been metal,it may have been different. The flutter started instantly,and at a speed that I had already tested,but that had obviously weakened the internals.
So, what Lyman and M-B are probably seeing on the video is a series of snapshots of the tailplane vibrating,but the frequency may well be above the camera speed.I also agree that there is a slight distortion/alignment there as well.
If one looks at the photo on P9,#162,to me it appears that there is slightly more `up` elevator than the left one.I`m only gauging that from the shadows on the mass-balances.Now ,if one is putting UP elevator on one side ,and the tab on the opposite side is forcing Down,then there will be a difference in tension on both sets of elevator cables,and on the bolts holding both torque tubes together.Could lead to cable stretch,possibly sufficient to disengage from the pulleys and guides,or cause the bolts to `fret` or loosen.
`Voodoo` appears to have that happen,but there again does not appear to be a comprehensive report about it`s failure either.

[ClippedCub]

If one looks at the photo on P9,#162,to me it appears that there is slightly more `up` elevator than the left one.I`m only gauging that from the shadows on the mass-balances.Now ,if one is putting UP elevator on one side ,and the tab on the opposite side is forcing Down,then there will be a difference in tension on both sets of elevator cables,and on the bolts holding both torque tubes together.Could lead to cable stretch,possibly sufficient to disengage from the pulleys and guides,or cause the bolts to `fret` or loosen.

Think the chance is greater for the torque tube straining the attachments internal to the elevator. For Voodoo, the cables didn't jam, but everything getting beaten up if the 1st flutter mode is excited, so GG could be different.

The plunging, or first flutter mode is when the tips go up and down and the node, the part that doesn't move, is the centerline, as shown in the first part of the video. The counterweights and elevator deflection can drive this;

Fin flutter mode shapes--2nd version - YouTube

This would be different than the 2nd mode;

How to break a glider´s wing - YouTube

Hard to tell, but this excited the 3rd mode;

V tail flutter (cam: Flycamone2) - YouTube

God knows what this is, turning a solid to a fluid maybe, and back again'

fin flutter - YouTube

All of these are different than simple control surface flutter that sycamore experienced with the aileron, and up till now, everyone thought the trim tab was doing. Since the HS went into 1st mode flutter, if the video can be believed, then this could also be explained by an elevator getting loose from the torque tube, the fuselage snapping back from ti's twist, and getting things going. Bending the tab spanwise in this mode would explain why the inner part of the tab separated leaving the outer section attached. If the tab rod failed, the whole tab would flutter and rip off in one piece.

If the right elevator torque tube attachment failed, and the pilot was pulling 30 pounds of so, the left elevator would be over deflected and the right elevator up load would decrease causing the left roll without a pitch change. It would take a few 1st mode oscillations for the tab to fail, which would happen sooner if it was stiffened after Voodoo, and would happen very fast from the maybe 50 to a 100 hertz. Don't know if he camera can capture 50 hertz, so we might be looking at an illusion. But the theory ties everything in so far; the roll, the fuselage wrinkles, the tab breaking in half, the g occuring after the roll correction... .

Found the hinge moment report. The elevator bulge is standard for the D model
and there's still a slope change with Mach number on hinge moments.

http://naca.central.cranfield.ac.uk/reports/1947/naca-tn-1302.pdf

[ClippedCub]

I'll be at RENO next year; maybe I'll get to meet up with Clipped Cub

It'd be good to meet the people here. Airplane people are a special breed..

[thcrozier]

Yikes, my old V35 before 94-20-04 R2!!!

[Machinbird]

Nice job with the flutter videos Mr. Cub. :ok: You have posted almost all my favorite ones and posted them faster than myself, although Fred Haise's tail flutter video posted earlier on this thread is my all time favorite.

[sycamore]

CC/Anyone, any idea about the tailplane section; was it the earlier,or lower profile.or perhaps an H-model(p51H),which I`m assuming would be somewhat different. Do you know if there are any later reports which would deal with the later models,either Mustang,Bearcat,Jug..?

[ClippedCub]

Do you know if there are any later reports which would deal with the later models,either Mustang,Bearcat,Jug..? Might check;

NASA Technical Reports Server (http://ntrs.nasa.gov/search.jsp)

The sampling rate of the video is 30 frames per second. Thinking the HS isn't showing flutter, but the left HS deflected down could be a simple overload which would arise if the right elevator let go and the left elevator was over deflected as a result. This would still put all kinds of stress on the tab and the results would be the same.

The elevator was the weak point in early dive testing, and with the q's at Reno, the elevator load cycles during the race, the loads increasing on the right elevator due to the tab on the left one, and the higher horsepower, the elevator just gave up in the high g turn.

[Lyman]

The wrinkling of the skin is consistent with the stress on the fuselage, whether the image is part of the failure sequence or not, imo. Downforce and displacement reduces the "area" of the substrate, and the skin, unable to "shrink", wrinkles instead.

I have consistently been impressed with the life cycle of the skin on these birds. It is flexible, and the frame is definitely flexible. This suggests fatigue, and added drag in the circuit. I think there are areas of the airframe that would perform far better wrapped in FRP. It has greater elasticity, and the weight penalty might payoff in better times.

Control would be better, the contour and drag would be more consistent, and airflow would be more predictable.

In the turns, (all left, of course), the drag of the left Trim Tab on the elevator (with the PITCH UP) would be an ad hoc spoiler, and bleeding some energy with an already "deployed" fence, is an elegant use of otherwise wasted drag. It would be interesting to know if these issues resulted in some additional strengthening in this control.

I have the picture that with trim defeated on the right, it is somewhat like driving an automobile with only one front wheel power assisted.

[ClippedCub]

The wrinkling of the skin is consistent with the stress on the fuselage, whether the image is part of the failure sequence or not, imo.At first glance, the oil canning would be attributed to the high download on the tail. In this case with the one tab and the structural flexing across the elevator, the left elevator is making less tail down force than the right. This introduces torsion in the afterbody and it will show up as oil canning too.

Heard talk of the tailwheel be forced down against hydraulic pressure in the actuator. The maintenance manual shows an uplock and uplocks wouldn't be designed to take torsional loads from the fuselage excessively twisting.

There's also what appears to be denting on the turtle deck aboce the, '1', which would indicate the turtle deck in this area was stressed beyond the elasticity of the aluminum from the fuselage overly twisting.

http://www.avweb.com/newspics/reno-crash_trim-tab_tim-obrien_large.jpg

[Machinbird]

Notice how the remainder of the trim tab appears indistinct in the photograph that CC has just posted the link to. I wouldn't be surprised if it if fluttering at a high rate and causing that visual effect. Of course anything fluttering at that point in time was not relevant to the final outcome.

[Machinbird]

We have found two versions of the telemetry data informally relayed to us. One version indicates that the engine lost power due to fuel interruption from the high g level. Depending on the geometry of the fuel system in the Ghost, it may be possible to estimate peak g required to cause a fuel interruption.

Interruption of fuel can occur due to pump inlet conditions or pump outlet/engine inlet conditions.

Was the fuel pump on the Ghost a centrifugal pump or a positive displacement pump?

Was it tank mounted or engine mounted?

Is the fuel source a wing tank or some other tank?

Is there more than one pump involved?

[xmh53wrench]

I also notice in the slo-mo vid that the TT virtually vanishes for an instant before its inboard mount breaks away and then trails the elevator before departing the A/C. Please excuse my ignorance, but are the TTs cable operated, and if so how do they operate with one actuating tab above and one below the elevator surface? Does that mean when one is being pulled on the other is being pushed by the cables (in normal operation)? Also that dent over the number one, is evident in the build photos from 2009, I think its just a characteristic of the modification done to GGs spine.
...2009 Build photos
WarbirdAeroPress.com (http://www.warbirdaeropress.com/NewGallery/GG2009-1/index.html)
....2009 Run-up/ck flt
WarbirdAeroPress.com (http://www.warbirdaeropress.com/NewGallery/GG2009-2/index.html)

I am certainly not questioning the maintainers or the maintenance on this airplane but.......3 of what appear to be 1/4 bolts that attach the inboard elevator hub to its bellcrank? I dont know but seems mighty fragile if one were to consider the torsional stresses placed by pinning one of the TTs stationary. I personally am seeing the logic in the thought that a disconnect between the two elevators may have been the initial failure. Can somebody explain the twitch of GG in the video after passing Rare Bear (approx 7 min into the vid with GG above and in front of RB) (possibly rounding home or #1 pylon)?

Just some interesting info:
Tech INFO - Aircorps Aviation (http://www.aircorpsaviation.com/tech-info)

[ClippedCub]

Is there more than one pump involved?


Has a carb with a float. Float could have been forced down under excessive g creating flooding?


but are the TTs cable operated


Pushrod actuated. Also, elevators are interchangeable left and right, so the actuactor rod is visible on the top ofn one side.


Also that dent over the number one, is evident in the build photos from 2009, I think its just a characteristic of the modification done to GGs spine.


Thanks. Checking each other is what these forums are about, and why I'm here. Collectively, I think this can be figured out, and if we are confident enough, someone can be volunteered to present to the NTSB, to have them verify or disprove if it's something that could be overlooked. Concerned me everybody was jumping on the tab as the cause, and could see the NTSB falling into that trap with the Voodoo incident and the previous rudder tab loss cases. Maybe Voodoo had the elevator let go first which excited the tab.


Can somebody explain the twitch of GG in the video after passing Rare Bear


Probably from wake turbulance after being blown across the course. The winds were 280 degrees at 17 knots gusting to 21 knots. Also heard somewhere that a mountain rotor showed up sometime during the race.

[Lyman]

"If you can fly in the mountains, you can fly anywhere".......
Reno/Tahoe is an....interesting environment, for the pilot, year round.

Stead is in a "bowl", a well stirred one.

I lean toward elevator failure, as well. The right. The left elevator has stress attenuation (at the join/bellcrank) via the tab, the right takes more impact. The difference in load between the two is a chronic source of strain on the mounting cups at the bellcrank. I think the right elevator may have sheared, scrubbed some of the throughbolts that join it to the bellcrank. When it relaxed out of the airstream, the left elevator went stress critical, v/v the Trim Tab. Depending on the severity of the rotational failure of the Right elevator in its mounting, the LHS took on the load we see in Clipped Cub's image. The degree of torsional stress displacement of the tail would have unrigged the Tail feathers out of alignment with the wings and forward fuselage.

Permitted an extrapolation, this unrig makes the aft fuselage an emphatic right rudder, with sufficient input to recover the left roll, and roll the a/c back right. The fuselage recoils, and the a/c 'settles' into its ballistic path upward. It also recovers the Pitch Up, as the aft would be drooped, and deflected right.

This instant unrig/rerig suggests to me the loud noise heard at the time. The a/c at this speed is a drum, a skinned barrel, no different.

[xmh53wrench]

Wow I had the same though regarding Voodoo.....I wonder if there was much of a roll in his pitch up and accent. Regarding the stock function of the TTs so for ND trimming the left would be pulled and the right would be pushed into the airstream.

[Lyman]

Don't put too much into the parked image of VooDoo, the right elevator is not in alignment with the left, this does not mean what you see is what presented at the moment of failure. It would be interesting to read the record of VooDoo.

I don't see the Trim Tab as failing first, it is stressed by position, not load. It is comfortable in the configuration at failure, whilst the Elevators are not.

IOW, the tab is not experiencing any untoward loading. For it to fail, it needs a critical stress point to be exceeded. The failure of the right ELEVATOR explains this critical load nicely. I think Clipped Cub is on to this?

[xmh53wrench]

Thanks CC for your response and explanations.

EDIT: I now see I had the stock operation of the elevator trim tabs reversed, my bad..... Also, upon review of some cockpit photos I believe GGs trim were possibly electric, both pitch and roll.....switches on the left side of the cockpit.

[Machinbird]

CC
Has a carb with a float. Float could have been forced down under excessive g creating flooding?I don't think so. As the float gets heavier in the high g environment, the fuel it is displacing should get heavier also. The two should balance each other exactly out.

Stock P-51 fuel pressure appears to be in the 12-16 psi range with 19 psi max.
This is not such a high pressure that it could not be over-ridden at very high g.
The Stock P-51 used what appears to be a centrifugal fuel pump on the inboard aft corners of the wing fuel tanks (identified as the booster pump I believe.)
http://home.comcast.net/~shademaker/P51Pump.jpg

Sample calculations:
For 40 inches of height change (this is a SWAG* number), the pressure differential in a column of gasoline is about 1.04 psi.
At 15 g, the pressure differential in that same 40 inch column of gasoline is 15.6 psi. These numbers are the same orders of magnitude as the fuel pressure and indicate that interruption of fuel delivery may be possible at high g.
The Ghosts fuel arrangement was not stock, and the above calculations may not be relevant to the Ghost.
*For the uninitiated, SWAG = Scientific Wild Ass Guess.

[sycamore]

Wrench, if you go to those Tech Notes,and the `flight controls`,you can see the trim layout.Rudder and elevators used the same trim gearboxes.Also in the `tailwheel` section it shows the layout of the elevator/tailwheel /rudder steering mechanism,and locks.

[Von Klinkerhoffen]

Just some thoughts.

How do you know the GG was running a float carburettor ? Merlins were fitted with normal carburettors, pressure carburettors and injection carburettors. With all the modifications made to this a/c and its engine, I would not take for granted that anything was standard on this engine.

Re the engine cut(if it had a float carb)......if it was due to a rich cut, in all likelyhood you would have seen black smoke from the exhausts due to the over rich mixture....don't see that on any video or still. If it was running a stock fuel system , 12-16psi doesn't seem a lot of pressure to lift fuel to the carb inlet, especially with the reported extremely high G level experienced. So the engine cut could more likely be due to a brief interuption of fuel supply. Again I would be very sceptical that this a/c ran a stock pump/fuel system...maybe it does. With the amount of HP this engine was making , it would require much higher fuel flows and pressures surely ?

What makes you so sure the RH elevator or its torque tube failed ? If the RH tab was indeed fixed in the streamlined position , then the LH elevator/tab combination was imparting a force through the LH elevator structure to the RH elevator via the torque tubes and bellcrank. You are forgetting Newtons 3rd law of action and reaction. The forces are equal throughout the system but will be in opposite directions. When it fails, it will be at the weakest point, thats for the NTSB to find out !

Re the tail wheel extension..........it seems it was designed to extend under large G which the pilot was required to pull in the event of tailwheel extension failure. Not supprising it extended here in this case. It has also been mentioned that the doors also came off and this was an indication of structural damage to the tail due to flutter/twist/or the tab failure. The a/c was doing close to 500mph, I don't know of any a/c with a gear limiting speed in excess of 500mph ??? If you extend any gear at that speed, the doors are surely gonna come off !!

[skwinty]

In the words of Mark Twain:

"One gets such wholesale returns of conjecture out of such a trifling investment of fact" :ugh:

[Lyman]

Re: Fuel supply? If dependent on atmospheric pressure in any way, or even with positive pressure electronic pumps, isn't the fuel mass going to be quite lethargic at 12 G? One suspects cavitation, or vapor lock.

RH elevator. With the trim tab set for ND on the LEFT side, the LHE has some of its up force relieved at the Bellcrank. The RHE has no such advantage, and the stress is greater at the RHE join. This reverses with Pitch, and there is a chronic war twixt the right and left sides of the torque tube joins. Each reversal of elevator position causes two of these torsional reversals rather than one. So fatique is doubled, and the throughbolts are not designed for this, imo. (Notwithstanding the design consideration does not include these torsional challenges, originally).

What results is an inadvertent "warping" effect, through the hinge line of the Horizontal tail. The design is counter to such a consideration, imo. Again, if the design were to be carried through, and there is no reason to abandon the idea, the Torque tube would be a unit, not halves.

I select the RHE for failure because of this stress bias against it. I take note of the quote above. Mark Twain was editor of the "Territorial Enterprise" in Virginia City, just down the road from STEAD AFB, so that makes him a local, and had he lived, he likely would be flying some "contraption" at RENO each September.

He was an accomplished PILOT. SteamBoat wise.

For the Merlin, then. Fuel Injection? For the Mustang, CFRP tail feathers and Fuselage? Tame the skin, lose the drag. And a Stout Torque Tube for the els.

Klink: Newton's Third? In failure,the stress is differential, not opposite, imho. The Third applies to the controls' NET effect on the airframe?

[Machinbird]

It has also been mentioned that the doors also came off and this was an indication of structural damage to the tail due to flutter/twist/or the tab failure.However this observation flies in the face of pictures showing the tail wheel doors on in the final dive. (The side view picture.) After reviewing the video of the aircraft, I have yet to see anything leaving the aircraft other than the trim tab.

[sycamore]

C-C et al, just to go back to my earlier reference to the article by Space-Electronics; it refers to mass balancing of control surfaces,not specifically `tabs`,more as a unit and `Moment of Inertia`,but also considers Product of Inertia` being the spanwise distribution of mass balances on control surfaces.Also that this factor seems to be largely `ignored`.
In the Mustang case, the ailerons appear to be balanced along their span( indeed in `Wrench`s link to `Aircorps` there was an early modification to the Mustangs` ailerons to replace the left aileron mass balance,made of steel` with one of a non-magnetic material as it interfered with the compass detector in the wing.)
However, the elevators and rudder,have solid balances towards their tips in each case,and do not appear to be balanced along their span,,ie, not taking `product of inertia` into account.
In the event of `flutter` starting,for whatever reason I would suspect that there will be a very rapid and
strong torsional twisting between the elevators and along the elevators due to the mass balance concentration at the tips,and as visible in the `V` tail glider elevons.
I realise that the m-b weights may also be aerodynamic balances,and there is not a lot of room in front of the elevator to the rear spar unlike the ailerons which appear to be `shrouded` on top and bottom.Perhaps your contacts may know more about that.....Did NA miss a trick here when it was designed
ed; does anyone know of othe incidents of `flutter` on other types,either racing or airtesting,as it seems that Mustangs have had a few tab failures including rudders..?
NB.I have nothing against Mustangs,just want to explore all avenues if possible...

[Machinbird]

A few posts earlier I asked the question whether or not the Ghost had an elevator bobweight installed. I think I have found the answer, but look for yourself.
First Clue: From http://en.wikipedia.org/wiki/The_Galloping_Ghost_(aircraft)

Sanders renamed the aircraft Jeannie, after his wife. The aircraft was rebuilt with an eye to weight reduction. In the end, 600 lbs of was removed from the airframe.[14] Roy “Mac” McLain flew the aircraft in 1979 at the Reno Air Races. Shortly before the 1980 air races, the aircraft was damaged in a crash at the Van Nuys Airport. In a frantic effort, the aircraft was rebuilt and again flown by McLain, won the Gold Race at Reno just days later. At the 1981 Reno Air Races, Skip Holm piloted the aircraft to victory in the Unlimited Class Gold Race.

600 lbs removed from a P-51 is a lot of weight, I think I have found where 20 lbs of that weight came from.

Second Clue is this third hand post from post 291 in this very thread: http://www.pprune.org/6736071-post291.html

During qualifying Matt watched Galloping Ghost from inside the cockpit of Furias and could not believe how much trouble Leeward was having in keeping the Ghost in a stable pattern around the course.

Third clue is from TECHNICAL ORDER NO. 01-60J-29 found here: http://www.aircorpsaviation.com/Websites/aircorpsaviation/Images/60J-29.pdf

NORTH AMERICAN-INSTALLATION OF ELEVATOR INERTIA WEIGHT P-51B, P-51C, AND P-51D
1. PURPOSE.
To prevent reversal of the elevator control stick
forces during maneuvers, an elevator inertia weight
will be installed in accordance with the instructions
contained in paragraph 2. in all of the following airplanes.

Fourth clue from the same source:
http://home.comcast.net/~shademaker/P51ElevControl.jpg

The elevator control bellcrank assembly is mounted just aft of the cockpit on the flap torque tube. The twin up and twin down elevator cables run from the elevator control bellcrank assembly and attach to the two arms on the elevator bellcrank that we have seen previously. This was done for combat survivability reasons but it had certain other advantages as well.

Fifth clue is this picture from the tech order:
http://home.comcast.net/~shademaker/P51ElevControlBellcrnkwBob.jpg

Here we see what the elevator control bellcrank looks like and what the bobweight added to the bellcrank looks like.

Sixth and final clue is this picture segment brightened a bit to show the shadowed area taken from the build up of the Ghost. Do you see the elevator control bellcrank? It is mounted on the slightly copper colored shaft. Do you see a bobweight? Do you think you should be able to see it if it is there?
http://home.comcast.net/~shademaker/ElevControlBellcrank.jpg
Removal of the elevator bobweight could cause handling problems and could leave the elevators subject to flutter for the reasons just stated by sycamore since the bobweight acts to damp out oscillations in the inboard sections of the elevator, particularly if both pairs of cables are in place. I am fairly sure that the bobweight is not in the picture, but I am not 100 % positive.
Was it a victim of the long ago weight saving campaign? Could that be what happened to the starboard trim tab actuator as well?

[stressmerchant]

Was the bobweight there for stability reasons, or was it the flutter balance weight?

Were there any other balance weights?

[FoundationMetro]

Modern aircraft have bob weights installed mainly to solve phugoid problems. The bob weight has no effect on mass balance. Given the amounts of turbulence likely to be encountered during the race and the speeds, the elevators would have been better balanced with the weight distributed along the leading edge and not with most of it located in the horn.

[Lyman]

Machinbird. With respect, the Flap TT blocks the area where one expects to see the Bobweight. Flutter can happen with highly tensioned actuators, as these are not. Even with hydraulics. The cables would not be sufficiently robust to blank flutter, imho.I notice the default arm of the weight tensions Nose UP, curious the design thought behind that.

What a treat, your drawings, and comment, thanks.

[Machinbird]

Stressmerchant
Was the bobweight there for stability reasons, or was it the flutter balance weight? It appears that the P-51 had a bit of a tendency to experience stick force lightening at higher g levels without the bobweight. The Technical Order specifically states,. PURPOSE.
To prevent reversal of the elevator control stick forces during maneuversSo the bobweight was there for stability reasons and not for phugoid reasons.
Any tendency to stabilize the elevator was an added bonus.
Ideally you want the counterbalance mass evenly distributed and firmly attached to the control surface, but in practice this can be difficult. As I recall, my F-4 had rudder mass balances in a shielded horn near the tip and out of sight in the fuselage.
If you have time, read into this link about Strega and what happened when they switched to a "tube" engine. Tiger Paws (http://www.warbirdaeropress.com/articles/Tiger/Tiger.htm)

[xmh53wrench]

Lyman, I guess I'm looking at the drawing wrong, but the weight would want to rotate the bellcrank ccw (per drawing) thus pulling on the control rod on the stick actually moving it forward.....(nose down). Countering a severe positive g climb......or am I backwards? But could understand the need to remove some of it in racing conditions.

[sycamore]

If you guys go to `keypublishing.com` and look at `historic aviation` ,there is a thread about the restoration of a TF-51. There are a lot of photos,some relevant but near the end of p.2 there is a photo of the lower controls with the bobweight.

[Lyman]

Hi sycamore. I am basing my thoughts on a pushrod that is mounted above the pivot bearing of the stick, not below it. Hence forward stick pulls the pushrod forward, and the crank articulates CW. It is a guess, but it puts the minor bearing "inside" the Stick bearing, protecting it, and saving additional Stick length.

again, a guess.

[sycamore]

The `exploded view ` of the mod. is looking aft,and also the photo at #54 on that thread.The bobweight is forward of the stick pivot,so under `g` loading it pulls down increasing the `stick-force per G increment,and the same for negative G.In the TF51 case it may be further back as it`s got full dual controls.
I would think that for the weight reduction for racing there would be a lot of extra hardware,ex-mil, that could be removed without touching the controls,or maybe just reducing the bobweight somewhat..

[skwinty]

Three small hinges and 3 small screws held the trim tab in place.( on the original)

That should give an idea of the expected trim tab forces.

I am not surprised that the tab came off at the speeds and forces it experienced.

http://i997.photobucket.com/albums/af92/skwinty/elevatorandTT.jpg

[Machinbird]

Sycamore, thanks for the link to the TF-51 build.:ok:

[xmh53wrench]

web find, that claims this is P-51

http://kr2seafury.com/resources/_wsb_355x348_mustang-control-stick.jpg

Also, does anybody else hear a "POP" at the begining of the "medium speed" portion of the climb video, in addition to the "CLICK" heard later in the climb? Just wondering......

Oh, and thanks for the heads up on the tf-51 build up, thats pretty amazing stuff.

[stressmerchant]

So does the bobweight double as the balance weight? Or is there a specific balance weight?

Perhaps out the fitting near the tip?

Does anyone know what the original (fabric covered) and later elevator balance limits were?

[skwinty]

For those who may be interested, here are some excerpts from the original P51 flight manual


http://i997.photobucket.com/albums/af92/skwinty/fltman1.jpg

http://i997.photobucket.com/albums/af92/skwinty/fltman2.jpg

http://i997.photobucket.com/albums/af92/skwinty/fltman3.jpg

http://i997.photobucket.com/albums/af92/skwinty/fltman4.jpg

[ClippedCub]

Excuse the absence. It's fall around here and the GF scheduled a cabin vacation. Surprise.

Have found some change orders from back in the day, and the bob weight is included;

Tech INFO - Aircorps Aviation (http://www.aircorpsaviation.com/tech-info)

They strengthened the horizontal and vertical, but there are no tell-tale signs of any elevator problems, other than the plastic trim tabs and maybe the outer hinge. The mechanics would ensure the mods are complete on the current airplanes.

Also did a stress analysis of the torque tube and if I did it right, for a 9 g turn at Reno, it's only 5 kpsi. Yield for 2024-T3 is around 45 kpsi, so fatigue or outright failure of the tube is low probability. That leaves the attachment analysis. Contacted a restorer in Texas and will try to talk him into drilling off the D spar of a damaged elevator to get the attachment details. Or, if anybody has the blueprints, or details, that would be better.

[Machinbird]

I have found a picture of the ghost made during the engine run ups after joining the wing and fuselage. At that time, the bobweight is definitely not there.

The green circle marks where it would be visible. All that is there is the elevator control bellcrank upper arm.

A bobweight would mitigate the nose up input that occurred at the beginning of the accident.

http://home.comcast.net/~shademaker/Missing.jpg

[stressmerchant]

I'm intrigued. If I read the documents correctly, when they changed from fabric to metal elevators, they refitted the original balance weights. Also, there does not appear to be any individual balancing instruction - they merely put the balance weight in place, no actual measurement of the imbalance. Is this correct?

Sounds like the bobweight may have been acting as an additional balance weight as well. Hardly a case of distribution along the hinge line, but it may have helped.

Does anyone know what the actual balance requirements were?

[Lyman]

Clipped Cub

Per the picture of the torque tube install, it would appear to be a great deal more robust than its join to the elevator Rib. Going from torsion to shear to compression (at the elevator surface), the weak link looks to be the tube to Rib join. Focal stress on this area is chaotic, compared to the Tube's single stress purpose? (Torsion).

For wartime, the design is elegant. For racing, I keep thinking a full length torque tube, tip to tip, solves the problems of tab, elevator warp, and wear, plus asym roll? At some stage, an all new a/c will be needed. The nagging feeling is there, that to butcher these priceless relics beyond their designed purpose is arrogant, and obviously, risky.

imho

[gileraguy]

Lyman

Maybe they could modify the old warbirds more, but I am sure that anyone racing these aircraft wants to reduce the risk to anyone from structural failure.

As far as new built racers go, look at what has happened to the purpose built racers like Miss Ashley and Tsunami. I think that the sport is running up against the limits of technology and engineering.

Unless they restrict the big boys like the F1 Air-racing, they'll probably keep much as they have been.

[Lyman]

gileraguy

No rules in a knife fight. "Unlimited". Leeward exhibited some instability that was noticed by another competitor, that could not be put down to wind. However it derived, clearly he was at the ragged edge of control.

IMO I think the a/c was rushed into the race, he had little time in it, plus he had shown some impatience to get it to perform well.

At some level, the competition becomes "Jackass IV", with certain injury, and the level of risk well above the reasonable return. "My wings are shorter than yours", "I have the hot set up cooling system", "I'm pulling 140 inches", etc.

The line, the LIMIT, if you will, stretches to a certain point, then crumbles, and people will be killed.

Don't get me wrong, I don't go to RENO to see the AT-6's. Or Sean Tucker. I go to feel the ground shake.

[Machinbird]

stressmerchant
Sounds like the bobweight may have been acting as an additional balance weight as wellAfter giving this some more thought, I believe that this is correct with the following observations:
For low frequency oscillations, the bobweight would be relatively tightly coupled to the elevator and would act to damp such oscillations.
For higher frequency oscillations, the bobweight would not be as tightly coupled to the elevator due to deflection of the intervening structure and the likely smaller amplitude of oscillation.

Non-use of the bobweight could then result in enhancing lower frequency oscillations affecting the center of the elevator. Lower frequency resonances are the most important ones to control.

Additionally, removal of the radiators and associated structure may have affected the aircraft's basic resonant frequencies in the aft fuselage and caused a new problem.
Have a look at the following FAA Advisory Circular. This applies to Part 23 certificated aircraft, but is good guidance for anyone contemplating aircraft modifications. http://rgl.faa.gov/Regulatory_and_Guidance_Library/rgAdvisoryCircular.nsf/list/AC%2023.629-1B/$FILE/AC23-629-1b.pdf

[Machinbird]

Reported by EAA:
October 24, 2011 – The NTSB announced that it was unable to recover any images from cameras that were mounted on Jimmy Leeward’s modified P-51 Galloping Ghost that crashed at the Reno Championship Air Races in September.
The badly damaged cameras and memory cards were recovered from the debris field at Reno and initially the NTSB had hoped to retrieve at least some images from the memory cards. But the damage was too great.

[Desert Dawg]

Is there update on this tragic event..?

[xmh53wrench]

NTSB held a briefing today in Reno with some preliminary findings and data, and some safety recommendations.

Link for their archives (April, 10 2012)

National Transportation Safety Board (http://www.capitolconnection.net/capcon/ntsb/ntsb.htm)

Some very interesting info from some still photos regarding elevator trim tab positioning.....near as I can tell they are still trying to figure out what exactly caused the "upset" (as they are calling it) when the a/c over banks the turn.

[Charles E Taylor]

Reno Update.

More info here.


Press Release April 10, 2012 - NTSB Provides Investigative Update and Issues Recommendations to Increase Safety at Air Races (http://www.ntsb.gov/news/2012/120410.html)





Charlie

[AvMed.IN]

The findings of the National Transportation Safety Board suggests that the pilot had lost consciousness due to ‘overwhelming’ G forces. This occurrence in a modified 1940′s vintage aircraft is likely considering its high thrust to weight ratios amongst its contemporaries, with a structural strength of -2G to +9G, making it likely that G induced loss of consciousness (http://www.avmed.in/2012/06/g-loc-then-and-now/)(G-LOC) could have been the cause of this tragedy.

[Pilot DAR]

Yes, G-LOC can be a cause for a pilot to loose control of the aircraft. In a flight which (for that phase) seemed to be intended as primarily straight and level, something unusual had to cause the high G. Prevent that, and you've prevented the G-LOC. A pilot who knows that they are about to enter a high G maneuver, can plan for that event. A pilot who is surprized by it may have a much reduced tolerance...

[Machinbird]

Recently chatted with an NTSB investigator-not one of those working on this accident-who indicated that the final report is likely to be published within a month.

[Croqueteer]

:confused:I understood that g-lock was caused by prolonged exposure to high g, normally happening in a military jet.

[BackPacker]

I understood that g-lock was caused by prolonged exposure to high g, normally happening in a military jet.

Without training (straining techniques, breathing) or equipment you can get G-LOC at as little as 5G. You don't need a military jet for that. Any WWII military fighter, and any half-decent aerobatic trainer, will do 5G with no problem.

The G-LOC onset curve is complex but in certain situations it can happen in less than four seconds. You don't need "prolonged" exposure. See the figure in this article:

G-LOC, COULD IT HAPPEN TO YOU? (http://aeromedical.org/Articles/g-loc.html)

[Pittsextra]

Forgot about this but I’m not sure what any report can recommend that isn’t already fairly obvious.

So you have an aircraft, designed to be at the cutting edge of technology 70 years ago then gets cut and shut to a point where the people doing the cutting and shutting are accepted as the experts. There is a question over regulation. There is also a huge question over the amount of testing that was done. There should be a question over the physiological affects and what airmanship is demonstrated allowing 70+ year olds to compete. Then the positioning of the grandstand finishes it all off.

[Madbob]

NTSB released new documents yesterday.....


August 21, 2012

NTSB Releases Reno Documents http://www.avweb.com/images-avweb/mailtoicon.gifEmail this article (http://www.avweb.com/cgi-bin/udt/im.send.story.prompt?client_id=avflash&story_id=207232) |http://www.avweb.com/images/printicon.gifPrint this article (http://www.avweb.com/avwebflash/news/NTSBReleasesRenoDocuments_207232-1.html?type=pf)


By Mary Grady (http://www.avweb.com/cgi-bin/udt/im.author.contact.view?client_id=avflash&story_id=207232&title=NTSB%20Releases%20Reno%20Documents&author=Mary%20Grady&address=http%3A//www.avweb.com/avwebflash/news/NTSBReleasesRenoDocuments%5F207232%2D1.html&summary=The%20NTSB%20on%20Tuesday%20%3Ca%20href%3D%22http%3A//dms.ntsb.gov/pubdms/search/hitlist.cfm?docketID%3D51746%26CFID%3D256561%26CFTOKEN%3D820 86778%22%20target%3D%22%5Fblank%22%3Eposted%20online%3C/a%3E%20more%20than%20900%20pages%20of%20documents%20plus%20p hotographs%20related%20to%20its%20investigation%20of%20a%20f atal%20crash%20at%20last%20year%27s%20National%20Championshi p%20Air%20Races%20in%20Reno.%20Among%20the%20documents%20is% 20a%20careful%20examination%20of%20a%20video%20shot%20by%20a %20spectator%20at%20the%20event%2C%20which%20concludes%20tha t%20the%20Galloping%20Ghost%2C%20flown%20by%20Jimmy%20Leewar d%2C%20reached%20a%20maximum%20acceleration%20of%2017.3%20Gs %20after%20a%20roll%20upset%2C%20in%20which%20the%20airplane %20reached%20a%20roll%20angle%20of%2093%20degrees%2C%20left% 20wing%20down.%20The%20documents%20also%20examine%20several% 20photos%20that%20show%20the%20departure%20of%20a%20trim%20t ab%20from%20the%20airplane%27s%20elevator.%20Leeward%20and%2 010%20people%20on%20the%20ground%20were%20killed%20when%20th e%20racer%20crashed.%20The%20safety%20board%20said%20it%20wi ll%20release%20its%20final%20report%2C%20with%20a%20determin ation%20of%20probable%20cause%2C%20by%20the%20end%20of%20thi s%20month.), Contributing editor


http://www.avweb.com/images-avweb/clearpixel.gif

http://www.avweb.com/newspics/reno_ntsb.jpg

The NTSB on Tuesday posted online (http://dms.ntsb.gov/pubdms/search/hitlist.cfm?docketID=51746&CFID=256561&CFTOKEN=82086778) more than 900 pages of documents plus photographs related to its investigation of a fatal crash at last year's National Championship Air Races in Reno. Among the documents is a careful examination of a video shot by a spectator at the event, which concludes that the Galloping Ghost, flown by Jimmy Leeward, reached a maximum acceleration of 17.3 Gs after a roll upset, in which the airplane reached a roll angle of 93 degrees, left wing down. The documents also examine several photos that show the departure of a trim tab from the airplane's elevator. Leeward and 10 people on the ground were killed when the racer crashed. The safety board said it will release its final report, with a determination of probable cause, by the end of this month.


The docket contains summaries of interviews by NTSB investigators, maintenance (http://www.avweb.com/avwebflash/news/NTSBReleasesRenoDocuments_207232-1.html#) records (http://www.avweb.com/avwebflash/news/NTSBReleasesRenoDocuments_207232-1.html#), a meteorology report, a report on "survival factors" and more. "The information … is factual in nature and does not provide any analysis," the NTSB said. In April, the NTSB released (http://www.avweb.com/avwebflash/news/NTSBSuggestsChangesForRenoRaces_206504-1.html) a half dozen safety recommendations, so organizers could consider implementing them for this year's races, which are scheduled for Sept. 12 to 16. The Reno Air Racing Association, which organizes the races, said changes (http://www.avweb.com/avwebflash/news/RenoRacesGoodToGo_206733-1.html) have been made to the race course in an effort to better protect spectators. The insurance (http://www.avweb.com/avwebflash/news/NTSBReleasesRenoDocuments_207232-1.html#) premium for this year's event increased by $1.7 million, according to the association's website.


All so sad.

MB

[Pittsextra]

Factual medical information:-

The following information was obtained from the
FAA Forensic Toxicology Laboratory at CAMI:

"Ethanol, 58 mg/dL."


"FAR Section 91.17 (a) prohibits any person from acting or attempting to act as a crewmember of a civil aircraft while having 0.040 g/dL (40.0 mg/dL) or more alcohol in the blood. "

"Ethanol and methanol were however identified in muscle on postmortem toxicology. "

[maxred]

"FAR Section 91.17 (a) prohibits any person from acting or attempting to act as a crewmember of a civil aircraft while having 0.040 g/dL (40.0 mg/dL) or more alcohol in the blood. "

Do I infer from this quote that there is a suggestion of Mr Leeward having had a drink?????

Ethanol, and methanol, the base ingredient of the likes of Vodka, and Gin, is a derivative of oil. Ethanol for spirit production, is a refinement of the stuff you put in your car, or aeroplane.

Do you have figures for 'background' levels of either ethanol, or methanol, in every human, muscle tissue?

Evidence, as far as I know, of recent alcohol consumption, is taken from blood level, not muscle tissue.

This event was very tragic, and any suggestion that the pilot was not 'fit', is in my view ill placed.

I

[Pittsextra]

I think that when you pick through the bones of this sorry tale you find in almost every element a casual attitude.



Be that themodifications to the aircraft, the flight testing, the positioning of spectators, the record keeping and the pilot – incidentally has anyone seen Leeward’s personal flying log book?



Now itseems there is ethanol in the tissue. Draw your own conclusion as to what that means. Why nobody tested for blood alcohol levels goodness only knows. What is very interesting is that when some guy wraps his Tiger up and goes to the pub there is a cry ofirresponsibility.

[Pittsextra]

Ethanol, and methanol, the base ingredient of the likes of Vodka, and Gin, is a derivative of oil. Ethanol for spirit production, is a refinement of the stuff you put in your car, or aeroplane.
Additional information provided by the
NTSB IIC:


The fuel used by the accident aircraft did not contain ethanol or methanol. The accident aircraft had a modified "boil ‐off" cooling system that contained methanol.

So no ethanol in the plane... so to use your own words we are left with Vodka or Gin..

[BackPacker]

Evidence, as far as I know, of recent alcohol consumption, is taken from blood level, not muscle tissue.

I can well imagine in an accident like this, that when they finally find and identify the body of the pilot, there is not a lot of blood left to sample.

Heck, under 17.3G the guy may have started bleeding from ruptured vessels in his legs even before the impact. Anyone knows in more detail what happens in the human body under, say, more than 15G? All I have experience with is 6G.

[Pittsextra]

Put it another way - you crash your car into a bunch of people because the wheel falls off but you might have had a drink... Do you think they focus on how many "G" you pull in the crash or how many drinks you had??

[BackPacker]

Do you think they focus on how many "G" you pull in the crash or how many drinks you had??

An NTSB report should not focus on anything, but should list and analyze all the possible circumstances that may have anything to do with the accident.

If ever this results in a court case/insurance claim or whatever, then it's up to a judge, jury, claims adjuster or somebody like that, to decide which factor(s) was/were to blame.

[riverrock83]

There is a legally defined blood alcohol content but I haven't found anywhere a legally defined muscle alcohol content. I haven't found any studies (I'm Googling - I'm not a medical expert) which show a link between blood alcohol content and muscle alcohol content.

I understand that absorption is linked to water content of the tissue - but where are the studies? As tissues go, muscles have a large water content so relatively speaking will be able to absorb more alcohol than more fatty tissues.

Also how long after absorption is the alcohol eliminated from the muscle compared to blood / other tissues?

I haven't read through the docs but it says that its information only without analysis. Lets not jump the gun!

[Pittsextra]

Yes agree the NTSB but I was referring to the focus of the law.

However now you mention it given the aircraft needed to under go testing following modification other than a personal statement saying it had been done is there any documentation of these hours? What about the pilot who also needs to be current. where is his log book? Then to the alcohol point why was there no blood sample sent for analysis?

Seems its the wild west out there. Can you imagine the fuss if you drilled a "modified" Pitts special into a bunch of people in the UK with the documentation we find here?

I know some people look fondly on this type of sport but come on there is blinkered and then there is this!

[Pittsextra]

There is a legally defined blood alcohol content but I haven't found anywhere a legally defined muscle alcohol content. I haven't found any studies (I'm Googling - I'm not a medical expert) which show a link between blood alcohol content and muscle alcohol content.

No it is not reliable because of the degradation of the body and other variables but hence why its all the more surprising blood analysis wasn't done. That aside the level in muscle is broadly 0.8 of that in blood.. I.e 80mg in muscle would be 100mg in blood.

Although it is impossible to say what the situation truely was in the air given the lack of data.

[maxred]

The level of recorded ethanol in muscle tissue, is based on the water content. Complicated process, but the ethanol is trapped in the blood water, which soaks into the muscle tissue. Generally however, this level disipates after 90 minutes. It is used as a back up to breath testing, however, multiple variables are at play in this process, and every individual is different.


Because of wide inter-and intra-individual variations in the absorption rate of alcohol, attempting to calculation a person’s BAC based on information about the amount of alcohol consumed is not recommended

Back to the incident, agreed that a variety of elements are at play here, and it is right that ALL causes be fully investigated, reported, and dealt with. I think the FAA, NTSB, are doing this.

[Pittsextra]

This event was very tragic, and any suggestion that the pilot was not 'fit', is in my view ill placed.

http://http://dms.ntsb.gov/pubdms/search/document.cfm?docID=371103&docketID=51746&mkey=81814

Suggest you look at item 6.1 (pages 19/20) and review the work of fiction that was the pilots stated age and currency. He had an abilty to stop time as he claims to be 59 years old for 3 years. He'd done 2700 hours apparently in the Ghost, a plane whose log book records just 1447.2 hours..

[xmh53wrench]

Could somebody post up a logical reason for adding weight to the elevator and rudder counter weights, please.
Thanks...

[Plasmech]

Control surfaces have their own resonant frequency... i.e. they have a tendency to want to flutter. The weight is essentially a tuned mass damper.

[xmh53wrench]

Thanks, that makes a bunch of sense, and I guess in theory, adding weight may make them less prone to flutter at higher speeds. But I wonder what effect that extra weight would have on them in high g banked turns, or transient high g loads? Just trying to wrap my head around that particular modification.

[treadigraph]

He'd done 2700 hours apparently in the Ghost, a plane whose log book records just 1447.2 hours..

Although it does say 2700 hours on "Ghost", it also says 2700 hours on type - he also owned and frequently flew and raced a fairly stock P-51D "Cloud Dancer".

RARA paperwork, not FAA documents, errors rather than a deliberate fiction I'd suggest - probably reused old forms and forgot to update some info and put the wrong data in another box. Can't really see it as of particular relevance to the accident, just a small fact that the NTSB noted.

[Pittsextra]

Although it does say 2700 hours on "Ghost", it also says 2700 hours on type - he also owned and frequently flew and raced a fairly stock P-51D "Cloud Dancer".

RARA paperwork, not FAA documents, errors rather than a deliberate fiction I'd suggest - probably reused old forms and forgot to update some info and put the wrong data in another box. Can't really see it as of particular relevance to the accident, just a small fact that the NTSB noted.

Maybe but what all of this shows is the mind set.

I'm not sure how a 74 year old becomes 59 when you have to physically fill the form out - or you do 13500hrs, 2500hrs on type, in that actual aircraft - its all just a farce.

How is it really any different from these idiots who claim to be pilots when all they have done is Microsoft flight sim! Or the PPL (H) who applies to fly the Police EC145?

Has anyone seen his logbook? And if he is happy to blag his experience on the entry form, are his log book entries accurate? When he signed to say he had tested the Ghost with its current modifications - was the true or another fantasy?

What this shows is a complete disregard for the organisation at the very least. He was vein enough to feel the need to make false entries with regard to his age and flying experience.

Sadly this idiot didn't just wipe himself out but a great many others.

[treadigraph]

Fair enough, if you've already made up your mind...

However, I'm going to wait for the conclusions of the NTSB's final report when it's published.

[BackPacker]

Well, it might also be the other way around.

If you design and/or modify an aircraft to race specifically in a race such as Reno, your entry form will not be the first contact you have with the organization. In fact, the entry form will, in all likelihood, be considered both by you and the organization as an afterthought. A bit of bureaucratic paperwork to make sure the i's are dotted, the t's are crossed and the accountant and the insurance company get that warm fuzzy feeling from thinking everything is "in ordnung". But I bet the organizers knew about his participation, and the details of his participation, months or even years before he submitted his entry form.

So I can well imagine the pilot just copies last years form and sends it in. In fact, I know situations (not in flying, but elsewhere) where the organization just copied last years form as a favour to the pilot. Heck, they probably knew way, way more about the pilot and the plane from personal knowledge, than what's on the entry form anyway.

So to me this doesn't indicate a disregard for the organization or a specific mind set. In contrast, it shows me that this guy was probably very, very familiar with the organization and vice versa.

[Pittsextra]

OK talk me through the hours bit...

[Pilot DAR]

Backpacker raises a few valid points in general (I have no knowledge on the Reno crash, and no comment to offer specifically in respect of Mr. Leeward).

Pilots who are "familiar" with a type of flying or an organization can tend to blur the boundaries of the paperwork, and be tolerated doing so. It's a possible failing on both sides. The pilot wants to fly again/more (we all do), and the organization wants to encourage their participation in general, or at least not seem unwelcoming, so as to scare/anger others off.

I used to organize a local floatplane fly-in/airshow, which met the Transport Canada requirements for organization and control. The fact that we advertized it to the public at large was the line crossed to make it an "airshow", and subject to regulation. That same event continues to this year, but only as a "fly-in" now.

Anyway, we used to have pilots turn up for "the games" on the water - planned challenges for flying skill and maneuvering mostly on the water, usually timed. Everyone had to register with me to participate. Registering required the presentation of all of the valid paperwork for the pilot and aircraft.

I found three types of people: Those who were totally compliant, and had the paperwork to prove it, those whom I knew were not compliant, but never registered, and those who thought that they would participate without the paperwork. Many pilots would present themselves to me, and not only not have the paperwork, but actually admit that they did not have a pilot's license/C of A/insurance etc. I said to several with some surprise in my voice, "do you realize that that guy over there is a Transport Canada inspector, who's watching what's going on? You should go and hide!".

Now, when I know I will be flying someone else's aircraft, I try to "push" my paperwork at them, so they don't have to pull.

I know a lot of senior pilots, whom I admire immensely, and continue to learn from. I have notice that they tend to self regulate the types of flying they do so as to be less demanding in several senses. Something about superior judgement instead of superior skill (and stamina, I suppose). One more reason I respect them....

[Pittsextra]

I know a lot of senior pilots, whom I admire immensely, and continue to learn from. I have notice that they tend to self regulate the types of flying they do so as to be less demanding in several senses. Something about superior judgement instead of superior skill (and stamina, I suppose). One more reason I respect them....

Sure; i'm just not sure how that explains a hand written 2009 entry form gives the age at 59 instead of 72 or how you have time on that aircraft at 2500+ when the thing itself has only 1400, and total hours that vary wildly from 2009 thru 2011. Don't people just look at their logbook to find total hours?

Thing is if you just want to take a "yeah it will be ok lets self regulate" attitude that might actually be fine but we don't have that in aviation do we? We are no longer in the age of the Wright brothers and one thing this folksy wisdom ignores is that a bunch of innocent people died and perhaps when you look at all the "Don't knows" in the interviews with crew and engineering people perhaps everyone believed that everyone one else had things covered when in fact nobody did.

[Pilot DAR]

everyone believed that everyone one else had things covered when in fact nobody did.

Oh I just agree with that observation. This is the duty of care that we all have. The aviation system has many documentation mechanisms in place to objectively demonstrate that requirements have been met - we gotta use them!

I have no statement to make specifically about Mr. Leeward. In general though, a person who does not provide required information which is compliant, or provides information which contains incorrect information should have a red flag pop up in front of them. I do not condone flying under misrepresented circumstances.

The aerodynamics which seem to be a factor in the failure of the aircraft interest me much more. There is a process for certified aircraft to demonstrate adequate margins of mechanical strength of control systems, and flutter margins. I realize that this was not a certified aircraft, but I hope there is some equivalent testing process, particularly considering the high speeds involved, and risks to the public. I wonder how compliance with whatever those requirements are was demonstrated, and how this was documented.....

[BackPacker]

OK talk me through the hours bit...

I'll leave that to the NTSB if you don't mind. All I'm saying is that I'm not going to draw the same conclusion as you, based on the data from the entry form.

[Pittsextra]

I'll leave that to the NTSB if you don't mind. All I'm saying is that I'm not going to draw the same conclusion as you, based on the data from the entry form.

This is idiotic. You sticking your head in the sand will not change the numbers that are clearly written on a variety of pieces of paper...

[Pilot DAR]

sticking your head in the sand

Or, perhaps, different people jump to conclusions at different speeds...

[Pittsextra]

still won't change the numbers

[BackPacker]

...and reconciling the numbers will not reverse the tragedy.

In fact, my personal opinion is that regardless of which numbers are actually true, the pilot had plenty experience in what he was doing. I honestly don't care whether that experience was 1000 hours or 2700 hours or some other number. It was not his inexperience in flying that caused the tragedy, but a mechanical defect.

Like DAR said, I'm very interested in the aerodynamics, flutter, oscillations and other factors that caused the trim tab to separate.

[Pittsextra]

and reconciling the numbers will not reverse the tragedy.

but might stop it happening again.

In fact, my personal opinion is that regardless of which numbers are actually true, the pilot had plenty experience in what he was doing. I honestly don't care whether that experience was 1000 hours or 2700 hours or some other number. It was not his inexperience in flying that caused the tragedy, but a mechanical defect.

And that is the point. Its already clear that there have been a variety of false statements in entry forms and its clear that none of the people running this machine have very much in the way of quantifying the testing which is a requirement to find such defects in an environment that shouldn't have killed a bunch of others.

Like DAR said, I'm very interested in the aerodynamics, flutter, oscillations and other factors that caused the trim tab to separate.

Having some wet dream over the technology of it all is only addressing half of the problem. Since Leeward took over this Mustang even his FAA documentation becomes a shambles.

Me neither. Reno is its own world to some degree, and will remain that way. Paraphrasing the advertisement "What happens in Reno, stays in Reno." Yes, it is the wild west. Precisely that, better for it, and intransigently so. Get used to it.

This just sums up the retarded view held by those that are aged 12.

Much the same as the Isle of Man for motorcycle racing, actually.

No its not because had he tried to enter the TT his entry would have been rejected as he would have been too old to hold a race licence.

[Chuck Ellsworth]

Total time means S.F.A. as far as flying ability goes.

Age will have an effect on ones motor skills eventually......when will vary from individual to individual.

Personally I decided to retire a few weeks before I turned 70, as far as I know I was still fairly competent in my airplane handling skills when I decided to retire.

I did do some flying for pay since I retired but have now decided not to renew my pilots license medical so I won't be tempted to fly for money again.

Soooo.....this winter I will finish my sail plane license in California and then do recreational aerobatics in sail planes.....that is a lot less physically challenging than flying powered aerobatic airplanes and I don't need a medical to fly one. :ok:

My message is we should know when to limit our flying activities as we age.

P.S..:::::

I still do a in depth medical every year and my last one a couple of months ago found only one issue....I was low on vitamin D....

[Cows getting bigger]

The Wild West - does that mean we should all tak our rifles with us in case the Injuns ride over the horizon?

Let me get this right:

A highly modified aircraft with no significant airworthiness oversight. An EXPERIMENTAL sticker appears to suffice.

A pilot who appears to have been economic with the truth.

A course layout where a failure of any sort on the final turn severely threatens the crowd line.

About another 70 observations/recommendations from the NTSB.

Hmmm, I think I'll leave the gun at home and continue to mix with people who aren't cowboys.

[CF104]

Thanks, that makes a bunch of sense, and I guess in theory, adding weight may make them less prone to flutter at higher speeds. But I wonder what effect that extra weight would have on them in high g banked turns, or transient high g loads? Just trying to wrap my head around that particular modification. I think the mod you're talking about is the counterweight on the elevator control torque shaft aft of the cockpit. This weight was added to due to the P-51's tendency to get light on the elevator control during high positive G's. With this weight installed the stick forces increased with the onset of G instead of getting less.

Cheers,

John

[treadigraph]

How is it really any different from these idiots who claim to be pilots when all they have done is Microsoft flight sim! Or the PPL (H) who applies to fly the Police EC145?

Pittsextra, perhaps you'd care to share with us the details of your expertise in this particular tragedy? Or should we add "amateur accident investigation experts" to your list?

NTSB committee includes Hoot Gibson and Bill Kerchenfaut. I know who they are and have some appreciaton of why their expertise has been called upon - do you?

I trust their integrity. And await the conclusions of the NTSB. I'll not pre-judge Jimmy Leeward on the basis of incorrectly completed race application forms. If he's found wanting elsewhere then fair enough. My head is not in the sand, and neither is it up my backside.

Chuck Ellsworth: Age? Rubbish, I'd happily go flying with you anytime, mate! I can't imagine many better exponents of good airmanship!

[Chuck Ellsworth]

Thanks treadigraph, as time passes I often wonder how I managed to survive so long in aviation and never wrecked an aircraft.

A lot of the credit has to go to the many excellent captains I flew with when I was getting started.

However in the final analysis I somehow managed to say no when I got that feeling things were about to exceed my limits and I credit that with making the difference between failing and succeeding as a pilot..

Few pilots ever figure out that it is not rules and regulations and all the other checks and procedures that make for safe flight.....it is mainly using common sense and never betting your life on something that may kill you if you push to far.

When the airplane gets ahead of where you wanted it to be you have crossed the line from safe to unsafe.

I got fired from a few jobs by saying no to unsafe operations.....but I'm still here. :)

[Pittsextra]

I don't know why having an opinion on this has any relevance to what the NTSB report will finally conclude.

The published documents are interesting and for all of the things that you say don't matter or are irrelevant, namely age and flight time, they are exactly the things Leeward exaggerated.

Now I don't know why you would at 72 years of age hand write your age as 59 as he did in 2009. You can say age is irrelevant but clearly he didn't think so.

Then flying time - why is that hard to find? Don't you just look at your log book and copy the number?? What's with the 13500+? Any pilot can give theirs to a decimal place!

The final report will be interesting.

[Chuck Ellsworth]

Then flying time - why is that hard to find? Don't you just look at your log book and copy the number?? What's with the 13500+? Any pilot can give theirs to a decimal place!

You are quite wrong with that statement Pittsextra.

I can not give the exact number of hours I have flown during my career, I quit keeping a personal log book decades ago because there was no need to.

Hell I probably can't even come close to the exact number of hours I have flown.

Same goes for the different airplanes I have flown, however if I see an airplane picture and I have flown it I can remember that. :E

[Pittsextra]

Tread - I think you are getting muddled. I don't think one needs any expertise in air accident investigation - nor a desire to be an investigator neither pro or am to be able to read the published material and have a view.

This accident seems more than anything to make people very emotive.

Good airmanship means different things to different people and some have defended the cowboy, wild west nature of Reno. If that's the way people want to go flying then that's for them.

One question - at what point does it become unprofessional?

[Pittsextra]

So you don't keep a personal flying log book but you might be able to figure that when the FAA log for the total time on the Ghost airframe is circa 1400hrs you would fond it impossible to have done 2500+ in that particular plane right??

[Chuck Ellsworth]

So you don't keep a personal flying log book but you might be able to figure that when the FAA log for the total time on the Ghost airframe is circa 1400hrs you would fond it impossible to have done 2500+ in that particular plane right??

Of course, most any idiot could figure that out.

All I am pointing out is total time on anything is a very poor measure of ones skills period.

One of the reasons I quit flying for a living was the ever expanding need for paper work and ever expanding rules and regulations in aviation.

Here is another real shocker for you, I seldom if ever wore one of those hi-viz gismos so loved by the bureaucracy and in spite of my not wearing one no airplane or other vehicle on any airport ever ran me down....go figure. :confused:

[DeeCee]

Time for bed now Chuck.

[Chuck Ellsworth]

Time for bed now Chuck.

Naw....it's only 6 P.M. here on Vancouver Island......:)

[flydive1]

I don't know why having an opinion on this has any relevance to what the NTSB report will finally conclude.

The published documents are interesting and for all of the things that you say don't matter or are irrelevant, namely age and flight time, they are exactly the things Leeward exaggerated.

Now I don't know why you would at 72 years of age hand write your age as 59 as he did in 2009. You can say age is irrelevant but clearly he didn't think so.

Actually more than opinion you said that:

- the pilot was drunk
- he lied about his age
- he lied about his flight experience
- he lied about his age
- he modified his aircraft and did not test it.

About the age issue, could that be that the 59 is just a badly written 69? Would make sense.

[Pittsextra]

I didn't say he was drunk I merely reflected the report that highlighted the ethanol findings.

He did lie about his age (59, badly written 69 is not 72,73 or 74) for 3 years running. Regardless of people opinions on age and ability to fly.

He did lie about his flight experience. Regardless of peoples opinion on hours and ability.

Its my opinion that he lied about the level of testing given the lack of documentation and absence of memory from the crew under questioning. That is opinion nothing more.

[JEM60]

This all very sad to read. I guess to some extent it comes under the 'lot of old pilots, lot of bold pilots', familiarity breeding contempt etc., I met Mr. Leeward at Oshkosh some years ago, in fact, I have his baseball cap in a cupboard at home [long story].Like Treadi, I know the name Chuck Ellsworth and would have the same comments re flying with him as Treadi.
When I was a mere PPL, and stayed that way, I found that the best way to improve ones flying was to scare oneself s......s from time to time!!. Never made the same mistake again. Out of this disaster can olnly come good. RIP everyone.

[BackPacker]

and reconciling the numbers will not reverse the tragedy.
but might stop it happening again.

Only if the numbers were somehow part of the chain of incidents leading up to this accident. In other words: if the numbers on the entry form would have been correct, the accident would not have happened.

Somehow I don't see that connection. Regardless of whether the numbers were wrong out of carelessness or outright lies.

The only conceivable way I can see that that claim would be true, is if the pilot told outright lies because if he told the truth, he would not meet the acceptance criteria set by the Reno organization. But I have not seen a suggestion anywhere that that would be the case.

I don't think one needs any expertise in air accident investigation - nor a desire to be an investigator neither pro or am to be able to read the published material and have a view.

True. But don't be surprised if other people, who also may or may not have expertise in air accident investigation, pro or am, have a different view, and thus disagree with you. Particularly if not all the facts are known or public, and people have to infer things partly based on their own experience.

And in situations like that, the one making the boldest claim is the one that will receive the most flak.

[Pittsextra]

Backpacker - I completely agree with all of that.

I don't think the hours or age made any difference to the accident. What I draw from the deception or casual attitude to these forms is that it's likely it carried to the flight testing given it's largely self certificated.

Without documents to suggest otherwise I don't think that can be ignored.

There is always a fondness for the maverick, devil may care styled hero. At some point it just becomes reckless. It takes no skill to be reckless.

[Machinbird]

Factual medical information:-

The following information was obtained from the
FAA Forensic Toxicology Laboratory at CAMI:

"Ethanol, 58 mg/dL."


"FAR Section 91.17 (a) prohibits any person from acting or attempting to act as a crewmember of a civil aircraft while having 0.040 g/dL (40.0 mg/dL) or more alcohol in the blood. "

"Ethanol and methanol were however identified in muscle on postmortem toxicology. "
You have to remember that this is raw NTSB data that has not been officially interpreted as to its import.....
It so happens, that carbohydrates decompose to form alcohols among other things.
Judging from the violence of the impact, it is likely that several hours lapsed before any tissue from the pilot was identified and collected. What measures were then taken to preserve this tissue?

A clue that this alcohol reading is decomposition related is that methanol was detected. You had better not be drinking that stuff unless you want to go blind!
It is a poison.

Without formal interpretation of the results, I will have to assume that the ethanol is also resulted from decomposition.

Take a look at this link for more information: Fermentation in Blood Samples Produce....Alcohol - Arizona DUI Laws Attorney Lawyer Phoenix DUI Drunk Driving Defense Extreme Penalties In Scottsdale (http://www.azduiatty.com/fermentation-in-blood-samples-produce-alcohol.htm)

[NigelOnDraft]

The Medical Report points out the coolant had methanol and the crash site itself contained ethanol prior the crash:The fuel used by the accident aircraft did not contain ethanol or methanol. The accident aircraft had a modified “boil‐off” cooling system that contained methanol. There were alcohol (i.e., ethanol) containing beverages in the box seat area of the viewing stands where the accident aircraft impacted the ground.as well as:Methanol is produced postmortem, along with ethanol and other alcohols, in the putrefaction process. Methanol, commonly known as wood alcohol, is metabolized to formaldehyde. If ingested, the toxic and lethal levels of methanol are 10 mg/ml and 150 mg/ml, respectively.Given the methanol level established was way above the lethal level, I would not read too much into the Toxicology Analysis, unless you really know what you are talking about (which I do not) ;)

NoD

[Machaca]

Pitssextra:
He did lie about his age...

He did lie about his flight experience.

Its my opinion that he lied about the level of testing...

Your genuflection to concluding he's a pathological liar is pathetic.

Please share with us what the intent would be for an air racer with 35 years experience at Reno to lie about trivial matters such as age. You challenge the integrity of an extremely well-known and highly regarded pilot with an exceptional catalogue of experience that is respected by the few who have done similarly.

You haven't even given the available documents a proper analysis!

Some of the presented forms contain several handwriting styles. Some are typed and hand signed. Who filled out which part of each form, where and when? Was it all done at the same moment?

On the RARA Pilot Data forms, it could easily be concluded that a pre-prepared form was signed by the pilot at an event registration table -- and at his last event he even corrected the age from 59 to 74!

This is air racing, not line ops. Have a go asking Jenson Button how many races he's started in his career, let alone number of hours.

Racing is dangerous sport -- air, water or ground -- and risk of injury or death to participants and spectators cannot be eliminated. If it scares you, don't attend.

[Pittsextra]

Mach :

I have no idea why he lied about his age, maybe he was just plain old self conscious about his age and used hair dye too??! How do I know ! But you can clearly see that he did. Pre-filled, handwritten, typed - he signed the form.

His integrity is challenged because regardless of his age the hours of experience claimed are just utter nonsense. If you look at the FAA forms form Ghost you might even conclude that this airframe would struggle to see a hundred hours since 1983 - yet on several occasions Leeward was claiming thousands.

Regarded maybe - an exceptional catalogue of experience you'd need to refer the reader.

As for motor racing drivers - a parallel which keeps being made. In that sport you are unable to progress from junior racing without providing results at each stage. Its all documented and retained by the national governing body or in the case of F1 the FIA.

Many make the point that experience counted in hours counts for jack - well the governing bodies around the world don't agree, they require documentation to stop loud people with big cheques telling the world they have 50000 hours of experience in every type available 5 minutes before they kill themselves... For example....

[B2N2]

I dont know what your beef is Pitts but your accusations seem meritless and akward.
It's not that hard to get addional info on Leeward:
EAA Sport Aviation - May 2011 (http://www.sportaviationonline.org/sportaviation/201105#pg38)
The man has flown 150 races in the Unlimited Class since 1976.
Nothing outrageous about the claim of 2500 hrs in make and model.
Galloping Ghost has been through several name changes and configuration changes during it's life.

[Pittsextra]

Meritless accusations...? Really? Well this from the NTSB:-

Board member Robert L. Sumwalt criticized Leeward and his team for failure to adequately analyze, document, and test the modifications they made to squeeze more speed from the Galloping Ghost.


“The way I look at it quite honestly, is, if you’re flying, if you’re modifying an airplane without fully understanding how those modifications can affect aerodynamics, then you’re basically just playing Russian roulette with an aircraft,” Sumwalt said. “As the chairman said, unlike Russian roulette, in this case when you go out and you do those things, you not only endanger your own life, but you potentially endanger the lives of others, and that is what happened in this particular case.”

[fernytickles]

Pitts,

So what's your point with all your posts? We all know the accident happened, too many people were maimed & killed, the NTSB facts are there for all to see in the documentation, regarding Jimmy, RARA, FAA, the course layout etc, etc.

You seem to be picking out only the negatives about Jimmy that contributed towards the accident. We can all read those facts too. Obviously without the aircraft going out of control, this accident would not have happened, but you seem to be ignoring the fact that there were other contributing factors towards so many being killed & injured

So is there a reason for posting just the negatives about Jimmy & ignoring any other factors?

[Brian Abraham]

Board member Robert L. Sumwalt criticized Leeward and his team for failure to adequately analyze, document, and test the modifications they made to squeeze more speed from the Galloping Ghost.

“The way I look at it quite honestly, is, if you’re flying, if you’re modifying an airplane without fully understanding how those modifications can affect aerodynamics, then you’re basically just playing Russian roulette with an aircraft,” Sumwalt said. “As the chairman said, unlike Russian roulette, in this case when you go out and you do those things, you not only endanger your own life, but you potentially endanger the lives of others, and that is what happened in this particular case.” The board member is merely saying what the Experimental Category is all about. In the land of the free aviators have the ability to experiment, anybody can design and build an aircraft. The FAA don't issue an Experimental Certificate for an aircraft lightly. They recognise because they are not necessarily designed/built/tested by professionals they don't have the level of safety that comes with a certificated aircraft, and hence they are operated on a "your risk" basis.

Fatalities suffered by the public at airshows occur from time to time. The organisers may do their very best, and often it's only luck at times that fatalities do not occur. Count spectator deaths/injuries here List of air show accidents and incidents - Wikipedia, the free encyclopedia (http://en.wikipedia.org/wiki/List_of_air_show_accidents_and_incidents)
Code of Federal Regulations

Part 21 CERTIFICATION PROCEDURES FOR PRODUCTS, ARTICLES, AND PARTS
Subpart H—Airworthiness Certificates

§ 21.191 Experimental certificates.

Experimental certificates are issued for the following purposes:

(a) Research and development. Testing new aircraft design concepts, new aircraft equipment, new aircraft installations, new aircraft operating techniques, or new uses for aircraft.

(b) Showing compliance with regulations. Conducting flight tests and other operations to show compliance with the airworthiness regulations including flights to show compliance for issuance of type and supplemental type certificates, flights to substantiate major design changes, and flights to show compliance with the function and reliability requirements of the regulations.

(c) Crew training. Training of the applicant's flight crews.

(d) Exhibition. Exhibiting the aircraft's flight capabilities, performance, or unusual characteristics at air shows, motion picture, television, and similar productions, and the maintenance of exhibition flight proficiency, including (for persons exhibiting aircraft) flying to and from such air shows and productions.

(e) Air racing. Participating in air races, including (for such participants) practicing for such air races and flying to and from racing events.

§ 21.193

Experimental certificates: general.

An applicant for an experimental certificate must submit the following information:
(a) A statement, in a form and manner prescribed by the Administrator setting forth the purpose for which the aircraft is to be used.
(b) Enough data (such as photographs) to identify the aircraft.
(c) Upon inspection of the aircraft, any pertinent information found necessary by the Administrator to safeguard the general public.
(d) In the case of an aircraft to be used for experimental purposes--
(1) The purpose of the experiment;
(2) The estimated time or number of flights required for the experiment;
(3) The areas over which the experiment will be conducted; and
(4) Except for aircraft converted from a previously certificated type without appreciable change in the external configuration, three-view drawings or three-view dimensioned photographs of the aircraft.

[Pittsextra]

The board member is merely saying what the Experimental Category is all about. In the land of the free aviators have the ability to experiment, anybody can design and build an aircraft. The FAA don't issue an Experimental Certificate for an aircraft lightly. They recognise because they are not necessarily designed/built/tested by professionals they don't have the level of safety that comes with a certificated aircraft, and hence they are operated on a "your risk" basis.

Read this and then tell me you conlude the same..

http://www.rgj.com/article/20120827/EVENTS05/308270027/NTSB-Reno-Air-Races-crash-caused-by-cracked-screws-untested-modifications-

Pitts,

So what's your point with all your posts? We all know the accident happened, too many people were maimed & killed, the NTSB facts are there for all to see in the documentation, regarding Jimmy, RARA, FAA, the course layout etc, etc.

You seem to be picking out only the negatives about Jimmy that contributed towards the accident. We can all read those facts too.

So is there a reason for posting just the negatives about Jimmy & ignoring any other factors?

I don't think we can all read these facts. Seems to me that there are some very obvious human factors in this and it seems nobody stood up to stop this insanity.

Take a look at the maintenance log and compare that with the table called Flight and data log (appendix B) under the data recorders section.

The pilot declares in the maintenance log in August 2009 that all flight testing has been done and yet there is just 19 minutes of flight data. This guy that seems to have many fans was, to use the venacular, just taking the p155.

[fernytickles]

Ok, so what is your point? If you are so sure of this, why not write to the FAA, the NTSB & RARA? Posting it on here is about as effective to the future of air racing safety as a chocolate fire guard.

[Pittsextra]

I don't see PPRuNe as something to change the world! Its just idle banter and chit chat with other pilots - or maybe you see it differently?

[DeltaV]

Its just idle banter and chit chat with other pilots
Gotta say your seeming obsession with this takes it somewhat far from idle banter and chit chat.

Interesting, though, what that piece says about modifications, maintenance and race speeds but it's not even as if the Ghost was the fastest ever P51 Reno unlimited. I think that honour goes to Strega, but maybe they're more conscientious or professional or whatever you want to call it.

[B2N2]

Despite my earlier statement I'm starting to lean in the direction of Pittsextra.
In our society there is a strong tendency turn a blind eye to the "folk-hero".
We are as a society very willing to come up with all sorts of excuses if one of our hero's falls of his pedestal.
I am talking about soccer players, rugby players, boxers, kick-boxers, golfers and other celebrities in general when they are caught :

drinking and driving
involved with organized crime
domestice violence
caught cheating


In his quest to beat Strega it seems Mr Leeward took a step too far.
Being the self made man and (NASCAR like) hero that he was he got away with it till this fatal event.
The NTSB report is clear.

In addition, the “filler material” used on both trim tabs increased their weight and changed their center of gravity, they said. That made the aircraft more sensitive to pitch control.


“It is likely that, had engineering evaluations and diligent flight testing for the modifications been performed, many of the airplane’s undesirable structural and control characteristics could have been identified and corrected,” the NTSB said.


*** Warning *** OFF topic ***

And am I the only one to think the chair(wo)man of the NTSB is quite the looker:

http://www.kunr.org/system/assets/images/file-access/227/full/ntsb-marquee.jpg

http://www.acc-tv.com/images/wjla/news/vidcap_wwhersman091109.jpg

[Pilot DAR]

hero that he was he got away with it

With the oversight present at an aviation event of this type, you only get away with something if someone lets you away with it.....

Focusing on the possible considerations of speed and flutter (of the elevator trim tab) as they related to this accident.... Before I can state that a flight test and the design being tested are satisfactory for certification, and thus "public" operation, I have to satisfactorily flight test to 110% of the certified limiting speed.

Do the authorities of these air racing events require evidence of satisfactory flight test to even 100% of the speed to be flown in the race? I know that it tends to defeat the purpose of the race, but this public operation of the aircraft, and the public should have some expectation of safety. Alternatively the "testing" phase of the demonstration of the capability of the aircraft might be better done a safe distance from the public. Perhaps it is now, I have know knowledge of the Reno air races.

[skwinty]

Ok, so what is your point? If you are so sure of this, why not write to the FAA, the NTSB & RARA? Posting it on here is about as effective to the future of air racing safety as a chocolate fire guard.
Last edited by fernytickles; 28th Aug 2012 at 13:23.


This...^^^^

Incidently, someone from this forum did and was made part of the investigation.

:D

[B2N2]

Source: Galloping Ghost (http://www.avweb.com/blogs/insider/AVwebInsider_GallopingGhost_207267-1.html)

August 28, 2012

Galloping Ghost: NTSB Nails It
By Paul Bertorelli





I took an hour and a half to attend Monday's NTSB hearing on the Reno Galloping Ghost accident. To say it was an eye opener is an understatement. It's not much of an exaggeration, in my estimation, to assert that before it even took off, Galloping Ghost was a crater looking for a grid reference. The NTSB found that it was flying at the very edge of its structural and performance envelope, if not well beyond it.

How could this have happened? Perhaps the easiest way to answer that is to suggest that it occurred because of an uncertain confluence of an owner and team willing to press the limits, a racing association with weak technical oversight and a regulatory agency—the FAA—that simply wasn't in the loop. The NTSB found that the aircraft was significantly modified, to include the removal of the belly scoop, the addition of a new canopy, structural mods to the fuselage and tail and a boil-off unit that's popular among Reno races as a supplemental cooling system.

These are hardly uncommon mods for this class of airplane, but the FAA had no records on any of this except the boiler. The owners hadn't reported the rest. Given that Reno racers are experimental, I'm not sure they're required to. Yet had they done so, opined the board, the agency would likely have demanded more flight trials to prove the mods. Would a structures guy have seen serious issues with the scoop removal just by inspecting it? Maybe. The NTSB said that much of the data it reviewed was unique to Galloping Ghost, even though other unlimited Reno racers are similarly modified.

Galloping Ghost was clearly built to win. It was flying faster than it ever had by at least 35 knots and the engine was delivering more power than was ever asked of it. It rounded its last turn at more than 400 knots, rolled sharply left, then pitched up violently into a 17-G uncommanded pull that the NTSB said no human could tolerate. Yet even before the moment the accident scenario began, there was strong evidence that the airplane was coming apart. Like most aviation events, Reno is widely filmed and the NTSB had an unusual amount of good imagery to investigate this accident. It did a superb job of analyzing it.

In lap two of the accident race, the imagery showed deformation in the aircraft's skin, indicative of overloading, and a visible crack or gap opened in the canopy. Wouldn't the latter have been evident to the pilot? The conclusion seems to be that it should have been. Why it wasn't is a mystery.

On the accident lap, the final failure mechanism was loose or fatigued screws holding the left trim tab in place. (The Mustang has a pair of trim tabs, for redundancy, but the right one on Galloping Ghost was fixed in place.) The investigation revealed that self-locking nuts were re-used on the left tab and old paint on the fasteners suggested they were last installed 26 years ago. The screws were incapable of being properly torqued.

In the final turn, something excited flutter in the loose tab. Was it wake turbulence from the proceeding airplane or sympathetic vibration with a structure that might have already been buzzing? We may never know. But we know the result. Flutter is as relentless and unforgiving a phenomenon as anything in aviation and it can destroy robust structures in mere seconds. In Galloping Ghost, the fluttering tab failed the trim actuator rod, rendering the trim useless. It didn't help that the P-51's elevator bob weights and balance had been significantly modified. Jimmy Leeward was doomed the instant the tab buzzed. It didn't actually depart the elevator until well into the uncommanded pitch up.

In my view, as surely as the technical explanation for this accident was a structural failure, the reason for it was a cultural failure. In her opening remarks, NTSB Chairman Deborah Hersman showed an acute understanding of why Reno pilots are willing to assume risk, but she also observed that exposing spectators to risk is quite another thing and an out-of-control airplane is a risk to everyone.

As pilots, we tend to dismiss the concerns of non-aviators as the paranoia of people who live uninspired lives in a cocoon, unwilling or unable reach out for the thrill that animates the rest of us. But there's a degree of cynicism in that dismissiveness and it can get people killed. In my view, the Galloping Ghost accident doesn't appear to be the result of willful ignorance, rather just plain ignorance. It also seems reasonable to assume, based on the NTSB's findings, that it could have been avoided if the owners had merely examined the risks critically and conducted more flight testing. As the NTSB suggested, the Reno Racing Air Racing Association needs better technical oversight of aircraft flying there and it has agreed to do that.

A word here about the NTSB, which a friend of mine once described as "government done right." I'm not easily wowed, but watching this hearing, I couldn't help but be impressed with the thoroughness and speed of the NTSB's probe into this accident. Moreover, the board members questioning of the investigators showed deep technical grasp of the issues. They asked what I'd ask. And then some. Deborah Hersman's queries and closing remarks were respectful and set just the right tone; firm, no-nonsense, but not overbearing. Positive changes have already come in the wake of this accident. Let's hope they stick.

A video of the full hearing will be available on the NTSB Web site in a few days. It's worth the time to watch. I'll add a link when it's available.

[Pilot DAR]

Wow, Paul Bertorelli's passage is excellent. I have spoken with him, and always enjoy what he writes.

One thing Paul wrote struck me:

In my view, the Galloping Ghost accident doesn't appear to be the result of willful ignorance, rather just plain ignorance.

I don't agree with this. I think it was willful ignorance. We expect plain ignorance from a new or non aviation person, or someone with limited resources. I expect that Mr. Leeward had the experience and resources to either do it right, or know that he should not have attempted it without appropriate prior testing and validation.

A public air racing course should not also be a flight test course.