Big Crash at Reno
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?
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?
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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
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
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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.
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.
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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.
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.
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stressmerchant
After 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_Gu...C23-629-1b.pdf
Sounds like the bobweight may have been acting as an additional balance weight as well
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_Gu...C23-629-1b.pdf
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Ghost's onboard cameras did not yield images.
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.
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.
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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
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.
Link for their archives (April, 10 2012)
National Transportation Safety Board
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.
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Reno Update.
More info here.
Press Release April 10, 2012 - NTSB Provides Investigative Update and Issues Recommendations to Increase Safety at Air Races
Charlie
More info here.
Press Release April 10, 2012 - NTSB Provides Investigative Update and Issues Recommendations to Increase Safety at Air Races
Charlie
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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 (G-LOC) could have been the cause of this tragedy.
Moderator
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...
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Final Report likely soon.
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.
Last edited by Machinbird; 1st Aug 2012 at 02:22. Reason: insert missing word
I understood that g-lock was caused by prolonged exposure to high g, normally happening in a military jet.
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I understood that g-lock was caused by prolonged exposure to high g, normally happening in a military jet.
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?
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.
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.
Last edited by Pittsextra; 1st Aug 2012 at 11:38.
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17.3 g!
NTSB released new documents yesterday.....
August 21, 2012
NTSB Releases Reno Documents
By Mary Grady, Contributing editor
The NTSB on Tuesday posted online 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 records, 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 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 have been made to the race course in an effort to better protect spectators. The insurance premium for this year's event increased by $1.7 million, according to the association's website.
All so sad.
MB
August 21, 2012
NTSB Releases Reno Documents
Email this article
By Mary Grady, Contributing editor
The NTSB on Tuesday posted online 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 records, 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 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 have been made to the race course in an effort to better protect spectators. The insurance premium for this year's event increased by $1.7 million, according to the association's website.
All so sad.
MB
Last edited by Madbob; 22nd Aug 2012 at 08:36.
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. "
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. "
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"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, 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
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.
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.
Last edited by Pittsextra; 23rd Aug 2012 at 09:05.
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..