Big Crash at Reno
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#207
With asymmetric elevators (by aspect), and at 450mph, I am going to say the tail section rotated (twisted) counter/clockwise as seen from aft. This would cause the additive roll left of the airframe. This explains the additive left roll that made vertical the wings as explained elsewhere caused by W/T. The buckles show this torsional aspect in concert with a Yaw and "drop" of the tail, meaning that the more emphatic elevator was the right one, and if it imparted a down force, it meant the tabs were "up", at the time the left tab was lost. this is consistent with carrying a Nose Down bias in the circuit.
That area of the airframe is hardly what one could call "stressed skin" so the damage is not particularly surprising, as it results from a structural failure in a design consideration that needn't have been addressed.
A secondary analysis might include the buckling resulted from a massive Nose Up input. With the elevators trending up, the tail would would endure a great download, a longitudinal collapse downward could have produced the 'extra' skin necessary to produce the wrinkling.
A combination of both mechanical issues is also possible.
With asymmetric elevators (by aspect), and at 450mph, I am going to say the tail section rotated (twisted) counter/clockwise as seen from aft. This would cause the additive roll left of the airframe. This explains the additive left roll that made vertical the wings as explained elsewhere caused by W/T. The buckles show this torsional aspect in concert with a Yaw and "drop" of the tail, meaning that the more emphatic elevator was the right one, and if it imparted a down force, it meant the tabs were "up", at the time the left tab was lost. this is consistent with carrying a Nose Down bias in the circuit.
That area of the airframe is hardly what one could call "stressed skin" so the damage is not particularly surprising, as it results from a structural failure in a design consideration that needn't have been addressed.
A secondary analysis might include the buckling resulted from a massive Nose Up input. With the elevators trending up, the tail would would endure a great download, a longitudinal collapse downward could have produced the 'extra' skin necessary to produce the wrinkling.
A combination of both mechanical issues is also possible.
Last edited by Lyman; 28th Sep 2011 at 00:37.
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Reno Air Race Relief Fund
I came across this on aafo.com. Seems like a kind gesture to help the victims through a very difficult time.
Family Assistance Fund
http://www.thinkkindness.org/files/AirRace_FAF.pdf
Family Assistance Fund
http://www.thinkkindness.org/files/AirRace_FAF.pdf
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Just found this, amazing photos, what a work of art
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Zulu Alpha
I believe that "wrinkling" image was not captured at the time of the accident but previous to the accident..
And thanks to Tredigraph below, I found the article that quoted Matt Jackson, President of the Unlimited class at Reno:
Jackson said the accident was the result of pilot error, not shoddy aircraft designs or the failure of the race organizers to ensure safe aircraft participate in the races.
“It was the mistake of one individual in making a critical decision — a decision that didn’t work out,” Jackson said. “It wasn’t deliberate. It was an accident — just like the accidents that happen every day out on the highway.”
According to Jackson, Jimmy Leeward, pilot of the ill-fated Galloping Ghost, made the mistake of using his “elevator trim tab” to control his plane during the Unlimited race on Friday, and the trim tab broke off, causing the plane to shoot into the air.
Jackson said the crash was an accident — not the result of sloppy designs or the lack of safety oversight on the aircraft.
Essentially, with the crash being an accident, it means the spectators might have an expectation of injury, as the tickets warn.
Jackson said the plane was safe if it was flown properly. He said Leeward made the mistake of using his trim tab on his tail to control his pitch, and the force of the speed was too much for that small piece of equipment, and it snapped off with catastrophic results.
“I know exactly what happened,” Jackson said, “and when the National Transportation Safety Board comes back with its report on the cause, they will say the same thing I’m saying.”
According to Jackson, Leeward’s elevator trim tab broke off when Leeward rounded turns No. 7 and 8.
“I always tell the pilots that we don’t touch the trim tabs on any of the fast airplanes,” Jackson said. “Apparently he was using the trim tab. It snapped off. That’s the pop we heard.”
When the trim tab broke, the Galloping Ghost shot into the air.
The G-force of about 9 caused Leeward to black out, and his body slumped forward, hitting the control stick and causing the plane to turn to the right and then down.
Photos of the plane support this, Jackson said. The back landing gear is down in photos of the plane just before it crashed. The landing gear is designed to deploy at 9 Gs, Jackson said.
In addition, Jackson said, Leeward was not visible in the cockpit of any of the photographs of the airplane’s final moments.
When racers fly, they set their shoulder harnesses to allow them to move around in the cockpit so that they can look over their shoulders for the other planes in the race. That would explain how Leeward disappeared from the cockpit, he said.
“The pilot blacked out or was dead in the airplane,” Jackson said. “His body came forward and he was pushed against the stick.”
“It’s going to come out that the trim tab failed,” Jackson said. “The plane that crashed was a very precise aircraft. Nothing had been short-cutted.”
It was an accident — not a design flaw, Jackson said."
The G-force from the sharp pitch caused Leeward to black out, and then fall on his control stick, which made the plane turn and then nosedive into the ground, said Jackson, who has been racing these planes for 20 years.
SO, my synopsis is:
Leeward , having gone faster than he ever had before, with an opportunity to pass into second place, disregards the instructions and trims against the nose up forces resulting from his increased speed.
He over-stresses the tab and then it breaks off the aircraft, resulting in a massive nose up force that he cannot hold against.
This force is sufficient to render Leeward unconscious and is testified by the deployment the tail wheel.
We all know what happened after that...
reason for edit, update reference
I believe that "wrinkling" image was not captured at the time of the accident but previous to the accident..
And thanks to Tredigraph below, I found the article that quoted Matt Jackson, President of the Unlimited class at Reno:
Jackson said the accident was the result of pilot error, not shoddy aircraft designs or the failure of the race organizers to ensure safe aircraft participate in the races.
“It was the mistake of one individual in making a critical decision — a decision that didn’t work out,” Jackson said. “It wasn’t deliberate. It was an accident — just like the accidents that happen every day out on the highway.”
According to Jackson, Jimmy Leeward, pilot of the ill-fated Galloping Ghost, made the mistake of using his “elevator trim tab” to control his plane during the Unlimited race on Friday, and the trim tab broke off, causing the plane to shoot into the air.
Jackson said the crash was an accident — not the result of sloppy designs or the lack of safety oversight on the aircraft.
Essentially, with the crash being an accident, it means the spectators might have an expectation of injury, as the tickets warn.
Jackson said the plane was safe if it was flown properly. He said Leeward made the mistake of using his trim tab on his tail to control his pitch, and the force of the speed was too much for that small piece of equipment, and it snapped off with catastrophic results.
“I know exactly what happened,” Jackson said, “and when the National Transportation Safety Board comes back with its report on the cause, they will say the same thing I’m saying.”
According to Jackson, Leeward’s elevator trim tab broke off when Leeward rounded turns No. 7 and 8.
“I always tell the pilots that we don’t touch the trim tabs on any of the fast airplanes,” Jackson said. “Apparently he was using the trim tab. It snapped off. That’s the pop we heard.”
When the trim tab broke, the Galloping Ghost shot into the air.
The G-force of about 9 caused Leeward to black out, and his body slumped forward, hitting the control stick and causing the plane to turn to the right and then down.
Photos of the plane support this, Jackson said. The back landing gear is down in photos of the plane just before it crashed. The landing gear is designed to deploy at 9 Gs, Jackson said.
In addition, Jackson said, Leeward was not visible in the cockpit of any of the photographs of the airplane’s final moments.
When racers fly, they set their shoulder harnesses to allow them to move around in the cockpit so that they can look over their shoulders for the other planes in the race. That would explain how Leeward disappeared from the cockpit, he said.
“The pilot blacked out or was dead in the airplane,” Jackson said. “His body came forward and he was pushed against the stick.”
“It’s going to come out that the trim tab failed,” Jackson said. “The plane that crashed was a very precise aircraft. Nothing had been short-cutted.”
It was an accident — not a design flaw, Jackson said."
The G-force from the sharp pitch caused Leeward to black out, and then fall on his control stick, which made the plane turn and then nosedive into the ground, said Jackson, who has been racing these planes for 20 years.
SO, my synopsis is:
Leeward , having gone faster than he ever had before, with an opportunity to pass into second place, disregards the instructions and trims against the nose up forces resulting from his increased speed.
He over-stresses the tab and then it breaks off the aircraft, resulting in a massive nose up force that he cannot hold against.
This force is sufficient to render Leeward unconscious and is testified by the deployment the tail wheel.
We all know what happened after that...
reason for edit, update reference
Last edited by gileraguy; 28th Sep 2011 at 07:39.
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Gilerguy, it was Matt Jackson, president of the Unlimited Class at Reno, who was quoted as having said that about not using the trim. Think the quote I saw was on a legal or insurance website discussing liability, linked from WIX.
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Hang on a second. How can using the trim tab at speed, which then breaks off NOT be a design flaw?
My reading of those comments from Matt Jackson come across as "these aeroplanes are safe, it was the pilot wot caused the accident."
Which is invariably the reaction after any accident when the pilot is not around to defend themselves. He sounds as if he's parceling blame over to Leeward to protect the rest of the class.
The old "it's purely pilot error" comments are invariably rubbish. There maybe an element of it, but for it to be the be all and end all is generally not usually correct.
Matt Jackson should probably learn to shut his face and wait for the actual report to come out.
My reading of those comments from Matt Jackson come across as "these aeroplanes are safe, it was the pilot wot caused the accident."
Which is invariably the reaction after any accident when the pilot is not around to defend themselves. He sounds as if he's parceling blame over to Leeward to protect the rest of the class.
The old "it's purely pilot error" comments are invariably rubbish. There maybe an element of it, but for it to be the be all and end all is generally not usually correct.
Matt Jackson should probably learn to shut his face and wait for the actual report to come out.
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made the mistake of using his “elevator trim tab” to control his plane
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Just found this, amazing photos, what a work of art
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RE: articles that quotes Matt Jackson and amazing photos, what a work of art
1. If this fellow truly believes trim tab use caused the accident, then the racers should be required to bring a set of elevators WITHOUT trim tabs and change to them before racing. With the money that is obviously spent on these aircraft, a spare set of elevators should not be excessive. My experience has been that leaving a function operational in the cockpit and telling pilots not to use it does not have a hight probability of success.
2. Trim tabs usually fail because of flutter, not static strength. Flutter usually occurs with a lightly loaded surface (one is is relatively faired with the control surface) not one that is highly loaded.
3. The pictures of the aircraft construction. The trim tab has a single rod actuator. For an aircraft that operates at this speed, a dual rod actuator would be much better. Also the elevator mass balance appears to be entirely in the horn. Again for aircraft operating in this speed range and under these conditions, spread out along the leading edge of the elevator would be better.
4. There appears to be a huge amount of space in the vertical stabilizer near where the leading edge of the horizontal attaches. Just cries out to have an electric actuator installed, the entire stabilizer made trimmable, and the trim tabs done away with altogether.
5. The work that was going on in the shop appears to have been first rate.
2. Trim tabs usually fail because of flutter, not static strength. Flutter usually occurs with a lightly loaded surface (one is is relatively faired with the control surface) not one that is highly loaded.
3. The pictures of the aircraft construction. The trim tab has a single rod actuator. For an aircraft that operates at this speed, a dual rod actuator would be much better. Also the elevator mass balance appears to be entirely in the horn. Again for aircraft operating in this speed range and under these conditions, spread out along the leading edge of the elevator would be better.
4. There appears to be a huge amount of space in the vertical stabilizer near where the leading edge of the horizontal attaches. Just cries out to have an electric actuator installed, the entire stabilizer made trimmable, and the trim tabs done away with altogether.
5. The work that was going on in the shop appears to have been first rate.
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gileraguy
gday. You have a 'belief' the photo predates the accident? That is interesting, and I can't respond, I never question a man's Faith. If the photo is from Tim O'Brien, it is Gold Standard. I know him, he is a fixture in the local aviation community, and his work is legend.
Somebody missed that blemish in the walkaround? I seriously doubt that. The a/c was cleared to the line looking like that? Have you reviewed my sketchy post on the mechanicals if it is real? Thoughts?
I think the video that shows the Ghost's hesitant over roll gives up what happened to cause the Pitch UP. It shows a mechanical issue (W/T is not eliminated), that the pilot reacted to: the ('extra') Roll left was not an indicated input for his flight path, so it was uncommanded. The response of the a/c in rolling back to the right shows a 'correction'. What remained of the a/c's flight path seemed gentle, and controlled.
The Pitch Up was almost certainly Pilot induced. It didn't resemble a casual exit of the circuit, it was in response to a Nose drop. An over-control, most definitely. CG is not set for stable, cruise flight, and the response in Pitch is touchy. Adrenaline and emergency are not conducive to ice water in the veins.
Pilot's vasculature is an issue, he seemed healthy and fit. However, there is a reason the rules start to discriminate against the aged in aviation. The wrinkling of the belly skin shows an inordinate amount of undesigned for stress, do you agree?
Regardless the cause, or its timing.
Question for you. Can an a/c like the Ghost Stall with a Pitch up of 60 degrees? In a 90 degree Roll?
gday. You have a 'belief' the photo predates the accident? That is interesting, and I can't respond, I never question a man's Faith. If the photo is from Tim O'Brien, it is Gold Standard. I know him, he is a fixture in the local aviation community, and his work is legend.
Somebody missed that blemish in the walkaround? I seriously doubt that. The a/c was cleared to the line looking like that? Have you reviewed my sketchy post on the mechanicals if it is real? Thoughts?
I think the video that shows the Ghost's hesitant over roll gives up what happened to cause the Pitch UP. It shows a mechanical issue (W/T is not eliminated), that the pilot reacted to: the ('extra') Roll left was not an indicated input for his flight path, so it was uncommanded. The response of the a/c in rolling back to the right shows a 'correction'. What remained of the a/c's flight path seemed gentle, and controlled.
The Pitch Up was almost certainly Pilot induced. It didn't resemble a casual exit of the circuit, it was in response to a Nose drop. An over-control, most definitely. CG is not set for stable, cruise flight, and the response in Pitch is touchy. Adrenaline and emergency are not conducive to ice water in the veins.
Pilot's vasculature is an issue, he seemed healthy and fit. However, there is a reason the rules start to discriminate against the aged in aviation. The wrinkling of the belly skin shows an inordinate amount of undesigned for stress, do you agree?
Regardless the cause, or its timing.
Question for you. Can an a/c like the Ghost Stall with a Pitch up of 60 degrees? In a 90 degree Roll?
Last edited by Lyman; 28th Sep 2011 at 14:48.
What else would you use it for? To make the tea?
Any momentary lapse of concentration and corresponding relaxing of the stick force would cause the glider to climb and not descend into the ground.
I cannot recall the source since I was just google-ing a couple of nights ago but here it goes;
The original P-51 design had a sea level max speed of 375 mph, hence a certain angle of incidence of the tail plane.
If this was not changed on the race aircraft you would need excessive nose down trim deflection which has the trim tab stick out further in the airflow.
This is what apparently caused the flutter and trim tab failure in the accident in the 90-ies.
From the slow motion accident sequence it is clear something failed prior to trim tab seperation. Might be the actuating rod or hinge mechanism.
It is hard to believe that somebody with this much racing experience (120+ races) would make a what would appear to be a "rookie" mistake.
But then again, accident reports are filled with experienced pilots.
I have to admit that despite the obvious tragedy this is fascinating stuff.
Like the death of Ayrton Senna.
Ayrton Senna da Silva
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gearhorn
Of course. Did you notice how many G the pilot was pulling prior to the "climb"? Just because the a/c is not gaining or losing altitude does not mean it is not experiencing wicked G.
Technically, the "additive" left ROLL is a wing drop, since the a/c wings are nearly vertical. In this attitude, again technically, the a/c is actually in a wicked climb, though you may call it a turn.
Once again, if those wrinkles are real, the cause can be determined, and the most likely cause is stress beyond critical design, in a commanded climb (OR PITCH UP). Or in an uncommanded (trim commanded) climb.
This means that the wrinkles preceded the TailWheel deploy.
Point of fact, the a/c may have experienced its most emphatic G load prior to the ascent. This means Leeward was likely incapacitated before the a/c started the ascent. Once 'established' in a manouver, the G relents, obviously.
If so, then manouver entry (PITCH UP) caused the buckling of the skin, the incapacitation of the pilot, the deploy of the TW, all before the dramatic gain in altitude, which was a result of the failure, not the cause.
Of course. Did you notice how many G the pilot was pulling prior to the "climb"? Just because the a/c is not gaining or losing altitude does not mean it is not experiencing wicked G.
Technically, the "additive" left ROLL is a wing drop, since the a/c wings are nearly vertical. In this attitude, again technically, the a/c is actually in a wicked climb, though you may call it a turn.
Once again, if those wrinkles are real, the cause can be determined, and the most likely cause is stress beyond critical design, in a commanded climb (OR PITCH UP). Or in an uncommanded (trim commanded) climb.
This means that the wrinkles preceded the TailWheel deploy.
Point of fact, the a/c may have experienced its most emphatic G load prior to the ascent. This means Leeward was likely incapacitated before the a/c started the ascent. Once 'established' in a manouver, the G relents, obviously.
If so, then manouver entry (PITCH UP) caused the buckling of the skin, the incapacitation of the pilot, the deploy of the TW, all before the dramatic gain in altitude, which was a result of the failure, not the cause.
Last edited by Lyman; 28th Sep 2011 at 15:24.
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No disagreement from me. My assumption quite obviously is that it is significant, however. Most design considerations transcend the 'normal' in Ulimited, eh? Do we have a spec on the skin in that area? The structure beneath?
I take your point
ps in slomo, do you see the tab depart, near the apex of the climb?
I take your point
ps in slomo, do you see the tab depart, near the apex of the climb?
Last edited by Lyman; 28th Sep 2011 at 16:52.
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Reno crash telemetry data.
Here are some telemetry data from the P-51 “Galloping Ghost” which crashed at Reno.
Airspeed around pylon 7 - 495 mph.
When the trim tab broke off the aircraft pitched up pulling 21 G's and airspeed reduced to 375 mph. (Tail wheel popped out, pilot slumped below view).
Airspeed around pylon 7 - 495 mph.
When the trim tab broke off the aircraft pitched up pulling 21 G's and airspeed reduced to 375 mph. (Tail wheel popped out, pilot slumped below view).
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21g - No way.
The Mustang limiting g was/is about 8 or 9 and fitted with a system to support an anti-g suit which was no doubt removed from the Ghost.
If 8 g, then design ultimate would normally be 12 g at which a wing is supposed to depart and at some lesser g if rolling.
Just cannot believe that the shortened wings would not fail at much over 12g.
Comments please from an aircraft designer or structural engineer.
The Mustang limiting g was/is about 8 or 9 and fitted with a system to support an anti-g suit which was no doubt removed from the Ghost.
If 8 g, then design ultimate would normally be 12 g at which a wing is supposed to depart and at some lesser g if rolling.
Just cannot believe that the shortened wings would not fail at much over 12g.
Comments please from an aircraft designer or structural engineer.
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Milt...
Yes - 21g seems unlikely. However NB at what the 8g / 12g ultimate was for - empty weight 7000lb, MTOW 12000lb.
Shorten the wings, take out a lot of weight, light fuel load (in fuselage tanks), and suddenly your ultimate 'g' increases by a large amount. Clearly it will take someone familiar with the structure / design to know what should fail at 12g / wing bending relief aspects etc. But I would not be amazed to see something approaching 20g not resulting in major failure.
NoD
Yes - 21g seems unlikely. However NB at what the 8g / 12g ultimate was for - empty weight 7000lb, MTOW 12000lb.
Shorten the wings, take out a lot of weight, light fuel load (in fuselage tanks), and suddenly your ultimate 'g' increases by a large amount. Clearly it will take someone familiar with the structure / design to know what should fail at 12g / wing bending relief aspects etc. But I would not be amazed to see something approaching 20g not resulting in major failure.
NoD