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R-22 structural failure?

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R-22 structural failure?

Old 28th Sep 2020, 04:40
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R-22 structural failure?

This is from Kathryn's Report of 27 Sept, 2020:

Kathryn's Report

A very strange incident.

Cheers,
Grog
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Old 28th Sep 2020, 04:50
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Tail rotor drive shaft damper failure? There is a yellow arc on the RRPM
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Old 28th Sep 2020, 05:44
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As there are no supports or bearings along the length of the shaft, it is possible to thrash the shaft around at certain RPM or above the normal range as well. One of the many compromises of the design, reduces cost and complexity.
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Old 28th Sep 2020, 09:13
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Could be "whirl mode".

Has happened before - UK Whirl Mode Accident

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Old 28th Sep 2020, 15:35
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Hmm, a Mariner,...in Florida?

I'm gonna guess someone mistook a pontoon for a gator, shot at it, missed, and hit the tail instead.
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Old 29th Sep 2020, 02:24
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I had trouble accessing the accident report via the above link to Kathryn's Report, which linked me to a Cirrus accident. I don't know what happened with the initial link, but I was able to find the NTSB Preliminary Report, via another approach.

The link to the NTSB Report:

https://app.ntsb.gov/pdfgenerator/Re...relim&IType=LA

I hope this link doesn't change.

Cheers,
Grog
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Old 29th Sep 2020, 02:31
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Originally Posted by Robbiee View Post
Hmm, a Mariner,...in Florida?

I'm gonna guess someone mistook a pontoon for a gator, shot at it, missed, and hit the tail instead.
That explanation makes a lot of sense. It is quite possible that the gator, being in heat, mistook a pontoon for a scaly, saurian lust object, misjudged his approach, entered "whirl mode" and wound up getting shot at for his efforts. The errant shot went wide and struck some sort of vital tail rotor drive bit, and things went down hill from that point on.

Other than the gator's wounded pride at his misdirected lust, there were no reported injuries.

Cheers,
Grogt
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Old 29th Sep 2020, 03:16
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Originally Posted by capngrog View Post
That explanation makes a lot of sense. It is quite possible that the gator, being in heat, mistook a pontoon for a scaly, saurian lust object, misjudged his approach, entered "whirl mode" and wound up getting shot at for his efforts. The errant shot went wide and struck some sort of vital tail rotor drive bit, and things went down hill from that point on.

Other than the gator's wounded pride at his misdirected lust, there were no reported injuries.

Cheers,
Grogt
,...or maybe upon seeing the gator making love to his pontoon freaked the pilot out, causing him to jerk the throttle wide open, which led to an overspeed,...then "bang", tail falls off!
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Old 29th Sep 2020, 07:50
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Maybe the R22 decided it was a gecko, and on getting a fright, shook its own tail off and ran in the other direction?
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Old 29th Sep 2020, 18:25
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Originally Posted by capngrog View Post
This is from Kathryn's Report of 27 Sept, 2020:

Kathryn's Report

A very strange incident.

Cheers,
Grog
Kathryn's Report: Robinson R44 II, N744TW: Fatal accident occurred May 17, 2019 in Alpine, Utah
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Old 29th Sep 2020, 18:29
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Hmm! R-44 pilot flies aircraft in dodgy conditions, which has precisely what to do with the whirl mode of the TR drive shaft?
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Old 29th Sep 2020, 19:33
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Hilico - this looks like someone caught out above cloud trying to find a way down and getting into a 'sucker's gap' before CFIT (or UCFIT) ends the day.
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Old 30th Sep 2020, 05:08
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That's not the accident that is the subject of this thread; however, it is interesting, and thanks for posting it. For some reason, the link in my Post #1 has become corrupted and no longer leads to information on the subject crash which involved a Robinson R-22 Mariner and which occurred at Fort Myers, Florida on 06 September, 2020. The best I can do at this point, is just refer you to the link in my Post #6 which leads you to the NTSB Preliminary Report of the 06 September accident. I just clicked on the Kathryn's link in my Post #1 and it led to a discussion of a crash of a Piper P-18A.

Technology is great when it does our bidding.

Cheers,
Grog
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Old 30th Sep 2020, 12:54
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Originally Posted by capngrog View Post
That's not the accident that is the subject of this thread; however, it is interesting, and thanks for posting it. For some reason, the link in my Post #1 has become corrupted and no longer leads to information on the subject crash which involved a Robinson R-22 Mariner and which occurred at Fort Myers, Florida on 06 September, 2020. The best I can do at this point, is just refer you to the link in my Post #6 which leads you to the NTSB Preliminary Report of the 06 September accident. I just clicked on the Kathryn's link in my Post #1 and it led to a discussion of a crash of a Piper P-18A.

Technology is great when it does our bidding.

Cheers,
Grog
The link is not corrupt, you simply posted the wrong link. You can't post the landing page of Kathryn's site, which is what you did, because it always changes content. You have to post the specific report url from the list on the right hand side of her page:

Kathryn's Report: Robinson R22 Mariner, N194HC: Accident occurred September 06, 2020 at Page Field (KFMY), Fort Myers, Lee County, Florida


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Old 30th Sep 2020, 13:13
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Originally Posted by aa777888 View Post
The link is not corrupt, you simply posted the wrong link. You can't post the landing page of Kathryn's site, which is what you did, because it always changes content. You have to post the specific report url from the list on the right hand side of her page:

Kathryn's Report: Robinson R22 Mariner, N194HC: Accident occurred September 06, 2020 at Page Field (KFMY), Fort Myers, Lee County, Florida
Okay, I think I understand. Thanks for the explanation. I thought that the link was to the story itself and not a link to the "landing page", but that's obviously not the case in this situation. I'll be more careful in the future.

Cheers,
Grog
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Old 7th Oct 2020, 20:14
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Originally Posted by capngrog View Post
That explanation makes a lot of sense. It is quite possible that the gator, being in heat, mistook a pontoon for a scaly, saurian lust object, misjudged his approach, entered "whirl mode" and wound up getting shot at for his efforts. The errant shot went wide and struck some sort of vital tail rotor drive bit, and things went down hill from that point on.

Other than the gator's wounded pride at his misdirected lust, there were no reported injuries.

Cheers,
Grogt
I spoke with the gator after the incident, he claimed strongly it was worth it and he'd do it again.
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Old 8th Oct 2020, 02:02
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Originally Posted by Ascend Charlie View Post
As there are no supports or bearings along the length of the shaft, it is possible to thrash the shaft around at certain RPM or above the normal range as well. One of the many compromises of the design, reduces cost and complexity.
Since when is there no bearing and damper in a R22 tail rotor driveshaft?
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Old 8th Oct 2020, 04:28
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Since when is there no bearing and damper in a R22 tail rotor driveshaft?
As distinct from, say, a B47 or a B206, which has multiple hanger bearings and driveshaft segments, I see from the parts cattle-dog that the R22 has only one damper close to the front, and the rest of the shaft to the tail rotor gearbox is able to wobble to a fair extent.

I say this with the uncertainty that comes with time, first flew those things in 1988 and the memory may have faded a little, and I don't recall seeing such an item as the damper back then...
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Old 8th Oct 2020, 04:38
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Originally Posted by Ascend Charlie View Post
As distinct from, say, a B47 or a B206, which has multiple hanger bearings and driveshaft segments, I see from the parts cattle-dog that the R22 has only one damper close to the front, and the rest of the shaft to the tail rotor gearbox is able to wobble to a fair extent.

I say this with the uncertainty that comes with time, first flew those things in 1988 and the memory may have faded a little, and I don't recall seeing such an item as the damper back then...
No support bearings, just a "lightly loaded" damper bearing.
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Old 8th Oct 2020, 05:21
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Certainly not rigid by Bell's standards but obviously more than sufficient, and as you allude to, a lot lighter. Your original statement gives the impression that there's no support between the intermediate and aft flex-plate, your second statement somewhat corrects that.
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