An in-flight breakup, but I can't see a probable cause. Did I miss it?
An in-flight breakup, but I can't see a probable cause. Did I miss it?
An in-flight breakup, but I can't see a probable cause. Did I miss it?
I thought that 15% margin for "any condition" was supposed to be provided (regs) for Vne to any analysis or testing for margin. Does this reduction to 10% due to unknown cause concern anyone?
No, because:
A) Vne is/was determined by multiplying Vd (design dive) by 0.9. See FAR 23.1505.
B) Full/abrupt control inputs anywhere near the speeds discussed are so far outside the aircraft's design envelope that it's essentially irrelevant. Such control inputs aren't appropriate above Va, let alone well past Vne.
If you are aware of another piece of reg that discusses 15% in relation to Vne, I'd be interested to learn more.
We can see how Tony rebuilt the rudder and had several layers of paint, but there is no information available that I can find that relates the rudder mass and CG to any change in flutter speed. Further, that aspect was not even mentioned in this report.
Flutter may not have been an issue. A large control input, especially when exceeding Vne, could result in a static overload. See AA587.
Is this what you are looking for?
All fractures exhibited characteristics consistent with static overload. No evidence of multiple dynamic loading fractures was found, nor evidence of fatigue characteristics or other preexisting damage.
I understand this to mean that the stabilisers were overloaded and basically each one snapped off, in one direction, with no cyclical loads leading to the break.
The whole situation is terrible.
Is this what you are looking for?
All fractures exhibited characteristics consistent with static overload. No evidence of multiple dynamic loading fractures was found, nor evidence of fatigue characteristics or other preexisting damage.
I understand this to mean that the stabilisers were overloaded and basically each one snapped off, in one direction, with no cyclical loads leading to the break.
The whole situation is terrible.
Exactly. That sentence is saying that there was no evidence of flutter. The airplane was simply overloaded.
... 220 knots for failure seems too close considering 190 knots, IAS, at 8500 is 220 TAS....
Tony and I swapped emails about painting last year. I believe he built a completely new rudder and painted it himself. I don't imagine there was any filler.
Where's the other prop blade? It was stated that it had an MT 3-blade prop, but the report only accounts for two blades?
Did he first repair the damaged rudder and then later build a new rudder?
. . .He had an RV6 that he had bought, constant speed prop. He admitted very candidly . . . he completely lost control and split s's , reaching near 300 m/h and a lot of G. . . .
No repair, just rebuilt. Link on post #11. There was a self etch layer, hi build layer (sanded down) a yellow/gold layer, a red layer, then the clear coat. No mention of rudder weight in the report IIRC.
Page 1 of I
Todd Gunther
Air Safety Investigator
Eastern Region
Date: September 21, 2013
Person Contacted: Amy Kelly (Spouse)
NTSB Accident Number: ERA13FA424
RECORD OF CONVERSATION
According to Mrs. Kelly, Her husband had the last annual inspection on the airplane done in
Texas. The plane was there for 7 days and while sitting on the ramp, the rudder was damaged by
the wind, prop blast, or jet blast. The rudder had a hole in it but her husband was able to fl y it
back to Cross Keys in March, and then built a whole new rudder. He then got a new gustlock, to
keep the rudder from being damaged again.
Page 1 of l
Todd Gunther
Air Safety Inves tigator
Eastern Region
Date: September 21,2013
Person Contacted: Butch H arold Delaney (Friend)
NTSB Accident Number: ERA13FA424
RECORD OF CONVERSATION
According to Mr. Delaney , the airplane had previously had its rudder damaged not too long ago,
and the pilot had duct taped the rudder, and flown it home. He then built a new rudder to replace
the damaged one.
This was his second accident. Both occurred in Hamilton Township .
During the first accident he had run t he airplane out of fuel.
Mr. Delaney also believed that the pilot was building another RV airplane when this accident
occurred.
My Rocket has a standard issue RV-8 tail group and thanks to an unfortunate flying experience I don't want to expound on further, I believe there is significant flutter margin in a properly constructed tail. I have personally been well in excess of 270 knots (followed by a 6 G pull at gross weight) with no damage of any kind. Based on that experience as well as the number of Rockets flying with -8 tails, I think there is more to this than a "simple" overspeed.
My Rocket has a standard issue RV-8 tail group and thanks to an unfortunate flying experience I don't want to expound on further, I believe there is significant flutter margin in a properly constructed tail. I have personally been well in excess of 270 knots (followed by a 6 G pull at gross weight) with no damage of any kind. Based on that experience as well as the number of Rockets flying with -8 tails, I think there is more to this than a "simple" overspeed.
One difference is your rudder has a single piece skin and isn't double-flush riveted like this one (and the Canadian -7 IIRC) was. Could that be significant?
The lower third of the rudder was the first piece that apparently separated
He admitted very candidly and in some detail that he had been trying to teach himself rolls in the RV. he completely lost control and split s's , reaching near 300 m/h and a lot of G. ... I have seen this scenario far too many times.
I read a lot about people losing control and "falling out" during a roll... how does it typically happen?
I read a lot about people losing control and "falling out" during a roll... how does it typically happen?
Yes, and the 8 has a .020 skin, with smaller area and formed trailing edge with a counterweight. The failed rudder(s) is(are) .016 skins with the riveted TE. This "8" rudder is also known as the 7 "short" rudder shipped with very early 7 kits. Significant? good question indeed.
+1 on what Widget said. To answer your question specifically, folks with no training make two mistakes when teaching themselves how to roll. The first is starting without getting the nose up. The second is maintaining back-pressure thruout the roll. As a result, the nose could be as much as 45 deg low when reaching the inverted position. Then panic sets in and bad things happen.
Tony
I really believe a lot of this discussion is rooted in denial. The report specifically states that there was no evidence of metal fatigue. It is a fairly cut and dry case of pilot error. . . . . but trying to compare this to other accidents, speculating on things like flutter, and looking for design flaws or poor construction (which there is no evidence of) is just making excuses for the pilot.
+1 on what Widget said. To answer your question specifically, folks with no training make two mistakes when teaching themselves how to roll. The first is starting without getting the nose up. The second is maintaining back-pressure thruout the roll. As a result, the nose could be as much as 45 deg low when reaching the inverted position. Then panic sets in and bad things happen.
Tony
Ya know, there is more than one of these stories, RV6 Vne is 210 mph. His VS/rudder did not come off. How do we assure that on a 7, get a 6 tail? I have one, actually the early 7, .020 skin, will it give me more margin? Was he braggin' or is it just more tolerant? Anyone know? PM?