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richard.goode(at)russiana
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 Posted: Mon Oct 18, 2010 7:50 am Post subject: Engine failure in Yak-50 |
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For those interested in more details:
<![if !supportLists]>· <![endif]>As had been suggested, I am sure the oil pressure would have fallen as the pressure release valve became unscrewed.
<![if !supportLists]>· <![endif]>Andy says that he noticed the zero oil pressure pretty much at the same time as the prop (as one would expect) went into coarse pitch.
<![if !supportLists]>· <![endif]>The engine then actually kept going for 9/10 minutes without oil, which is quite impressive.
<![if !supportLists]>· <![endif]>Oil temperatures didn’t go up simply because there was no oil and so nothing to measure! This of course was the reason for the engine failure – because the pressure release valve had not been wire-locked, it unscrewed and fell out.
<![if !supportLists]>· <![endif]>However it then totally seized and this is what broke the gearbox – hence the propeller continuing to windmill with a seized engine.
<![if !supportLists]>· <![endif]>The extent of the seizure was such that it is impossible to remove most of the cylinders!
<![if !supportLists]>· <![endif]>I would expect the CHT to have risen a bit, but only because a small part of it is oil-cooled, but the vast majority of cooling is through air, and of course he was at very low power settings in order to preserve the engine.
<![if !supportLists]>· <![endif]>In terms of gear-up of gear-down, I am sure gear-up is the safest way, but also, will cause far less damage to the aircraft.
Richard Goode Aerobatics
Rhodds Farm
Lyonshall
Herefordshire
HR5 3LW
United Kingdom
Tel: +44 (0) 1544 340120
Fax: +44 (0) 1544 340129
www.russianaeros.com
[quote][b]
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radiopicture
Joined: 23 Jun 2008
Posts: 263
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| Posted: Mon Oct 18, 2010 10:49 am Post subject: Engine failure in Yak-50 |
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Engine seized with broken gearbox, too. Well, OK... so that's how, which surprises me. Having access to the failed engine certainly trumps speculation.
On Oct 18, 2010, at 11:47 AM, Richard Goode wrote:
| Quote: | For those interested in more details:
· As had been suggested, I am sure the oil pressure would have fallen as the pressure release valve became unscrewed.
· Andy says that he noticed the zero oil pressure pretty much at the same time as the prop (as one would expect) went into coarse pitch.
· The engine then actually kept going for 9/10 minutes without oil, which is quite impressive.
· Oil temperatures didn’t go up simply because there was no oil and so nothing to measure! This of course was the reason for the engine failure – because the pressure release valve had not been wire-locked, it unscrewed and fell out.
· However it then totally seized and this is what broke the gearbox – hence the propeller continuing to windmill with a seized engine.
· The extent of the seizure was such that it is impossible to remove most of the cylinders!
· I would expect the CHT to have risen a bit, but only because a small part of it is oil-cooled, but the vast majority of cooling is through air, and of course he was at very low power settings in order to preserve the engine.
· In terms of gear-up of gear-down, I am sure gear-up is the safest way, but also, will cause far less damage to the aircraft.
Richard Goode Aerobatics
Rhodds Farm
Lyonshall
Herefordshire
HR5 3LW
United Kingdom
Tel: +44 (0) 1544 340120
Fax: +44 (0) 1544 340129
www.russianaeros.com
| Quote: |
style="color: blue; text-decoration: underline; ">http://www.matronics.com/Navigator?Yak-List
blue; text-decoration: underline; ">http://forums.matronics.com
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[quote][b]
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viperdoc(at)mindspring.co
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| Posted: Mon Oct 18, 2010 12:35 pm Post subject: Engine failure in Yak-50 |
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Sorry Eric, I wrote my response before seeing that you had already seen Robs post.
Doc
From: owner-yak-list-server(at)matronics.com [mailto:owner-yak-list-server(at)matronics.com] On Behalf Of Eric Wobschall
Sent: Monday, October 18, 2010 1:47 PM
To: yak-list(at)matronics.com
Subject: Re: Engine failure in Yak-50
Engine seized with broken gearbox, too. Well, OK... so that's how, which surprises me. Having access to the failed engine certainly trumps speculation.
On Oct 18, 2010, at 11:47 AM, Richard Goode wrote:
For those interested in more details:
· As had been suggested, I am sure the oil pressure would have fallen as the pressure release valve became unscrewed.
· Andy says that he noticed the zero oil pressure pretty much at the same time as the prop (as one would expect) went into coarse pitch.
· The engine then actually kept going for 9/10 minutes without oil, which is quite impressive.
· Oil temperatures didn’t go up simply because there was no oil and so nothing to measure! This of course was the reason for the engine failure – because the pressure release valve had not been wire-locked, it unscrewed and fell out.
· However it then totally seized and this is what broke the gearbox – hence the propeller continuing to windmill with a seized engine.
· The extent of the seizure was such that it is impossible to remove most of the cylinders!
· I would expect the CHT to have risen a bit, but only because a small part of it is oil-cooled, but the vast majority of cooling is through air, and of course he was at very low power settings in order to preserve the engine.
· In terms of gear-up of gear-down, I am sure gear-up is the safest way, but also, will cause far less damage to the aircraft.
Richard Goode Aerobatics
Rhodds Farm
Lyonshall
Herefordshire
HR5 3LW
United Kingdom
Tel: +44 (0) 1544 340120
Fax: +44 (0) 1544 340129
www.russianaeros.com
| Quote: | | style="color: blue; text-decoration: underline; ">http://www.matronics.com/Navigator?Yak-Listblue; text-decoration: underline; ">http://forums.matronics.comstyle="color: blue; text-decoration: underline; ">http://www.matronics.com/contribution |
0123456789 | Quote: | | style="color: blue; text-decoration: underline; ">http://www.matronics.com/Navigator?Yak-List |
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1 | Quote: | | style="color: blue; text-decoration: underline; ">http://www.matronics.com/Navigator?Yak-List |
2 | Quote: | | style="color: blue; text-decoration: underline; ">http://www.matronics.com/Navigator?Yak-List |
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[quote][b]
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radiopicture
Joined: 23 Jun 2008
Posts: 263
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| Posted: Mon Oct 18, 2010 2:35 pm Post subject: Engine failure in Yak-50 |
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No problem, Doc.
So what is it that caused it to shear? Is that a deliberate design to prevent the engine from twisting off it's mounts from prop momentum? Otherwise, you'd think there wouldn't be enough inertia to just break free like that.
On Oct 18, 2010, at 4:17 PM, Roger Kemp M.D. wrote:
| Quote: | Sorry Eric, I wrote my response before seeing that you had already seen Robs post.
Doc
From: owner-yak-list-server(at)matronics.com (owner-yak-list-server(at)matronics.com) [mailto:owner-yak-list-server(at)matronics.com (owner-yak-list-server(at)matronics.com)] On Behalf Of Eric Wobschall
Sent: Monday, October 18, 2010 1:47 PM
To: yak-list(at)matronics.com (yak-list(at)matronics.com)
Subject: Re: Engine failure in Yak-50
Engine seized with broken gearbox, too. Well, OK... so that's how, which surprises me. Having access to the failed engine certainly trumps speculation.
On Oct 18, 2010, at 11:47 AM, Richard Goode wrote:
For those interested in more details:
· As had been suggested, I am sure the oil pressure would have fallen as the pressure release valve became unscrewed.
· Andy says that he noticed the zero oil pressure pretty much at the same time as the prop (as one would expect) went into coarse pitch.
· The engine then actually kept going for 9/10 minutes without oil, which is quite impressive.
· Oil temperatures didn’t go up simply because there was no oil and so nothing to measure! This of course was the reason for the engine failure – because the pressure release valve had not been wire-locked, it unscrewed and fell out.
· However it then totally seized and this is what broke the gearbox – hence the propeller continuing to windmill with a seized engine.
· The extent of the seizure was such that it is impossible to remove most of the cylinders!
· I would expect the CHT to have risen a bit, but only because a small part of it is oil-cooled, but the vast majority of cooling is through air, and of course he was at very low power settings in order to preserve the engine.
· In terms of gear-up of gear-down, I am sure gear-up is the safest way, but also, will cause far less damage to the aircraft.
Richard Goode Aerobatics
Rhodds Farm
Lyonshall
Herefordshire
HR5 3LW
United Kingdom
Tel: +44 (0) 1544 340120
Fax: +44 (0) 1544 340129
www.russianaeros.com
0123456789012345
6
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[quote][b]
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viperdoc(at)mindspring.co
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| Posted: Mon Oct 18, 2010 6:23 pm Post subject: Engine failure in Yak-50 |
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Not sure but I think I heard that there is a design shear point in shaft. But, if that were so why would a prop strike not do the same.
So the answer is I do not know.
Doc
From: owner-yak-list-server(at)matronics.com [mailto:owner-yak-list-server(at)matronics.com] On Behalf Of Eric Wobschall
Sent: Monday, October 18, 2010 5:27 PM
To: yak-list(at)matronics.com
Subject: Re: Engine failure in Yak-50
No problem, Doc.
So what is it that caused it to shear? Is that a deliberate design to prevent the engine from twisting off it's mounts from prop momentum? Otherwise, you'd think there wouldn't be enough inertia to just break free like that.
On Oct 18, 2010, at 4:17 PM, Roger Kemp M.D. wrote:
Sorry Eric, I wrote my response before seeing that you had already seen Robs post.
Doc
From: owner-yak-list-server(at)matronics.com (owner-yak-list-server(at)matronics.com) [mailto:owner-yak-list-server(at)matronics.com (owner-yak-list-server(at)matronics.com)] On Behalf Of Eric Wobschall
Sent: Monday, October 18, 2010 1:47 PM
To: yak-list(at)matronics.com (yak-list(at)matronics.com)
Subject: Re: Yak-List: Engine failure in Yak-50
Engine seized with broken gearbox, too. Well, OK... so that's how, which surprises me. Having access to the failed engine certainly trumps speculation.
On Oct 18, 2010, at 11:47 AM, Richard Goode wrote:
For those interested in more details:
· As had been suggested, I am sure the oil pressure would have fallen as the pressure release valve became unscrewed.
· Andy says that he noticed the zero oil pressure pretty much at the same time as the prop (as one would expect) went into coarse pitch.
· The engine then actually kept going for 9/10 minutes without oil, which is quite impressive.
· Oil temperatures didn’t go up simply because there was no oil and so nothing to measure! This of course was the reason for the engine failure – because the pressure release valve had not been wire-locked, it unscrewed and fell out.
· However it then totally seized and this is what broke the gearbox – hence the propeller continuing to windmill with a seized engine.
· The extent of the seizure was such that it is impossible to remove most of the cylinders!
· I would expect the CHT to have risen a bit, but only because a small part of it is oil-cooled, but the vast majority of cooling is through air, and of course he was at very low power settings in order to preserve the engine.
· In terms of gear-up of gear-down, I am sure gear-up is the safest way, but also, will cause far less damage to the aircraft.
Richard Goode Aerobatics
Rhodds Farm
Lyonshall
Herefordshire
HR5 3LW
United Kingdom
Tel: +44 (0) 1544 340120
Fax: +44 (0) 1544 340129
www.russianaeros.com
| Quote: | | style="color: blue; text-decoration: underline; ">http://www.matronics.com/Navigator?Yak-Listblue; text-decoration: underline; ">http://forums.matronics.comstyle="color: blue; text-decoration: underline; ">http://www.matronics.com/contribution |
01234567
89 | Quote: | | style="color: blue; text-decoration: underline; ">http://www.matronics.com/Navigator?Yak-List |
0 | Quote: | | style="color: blue; text-decoration: underline; ">http://www.matronics.com/Navigator?Yak-List |
1 | Quote: | | style="color: blue; text-decoration: underline; ">http://www.matronics.com/Navigator?Yak-List |
2 | Quote: | | style="color: blue; text-decoration: underline; ">http://www.matronics.com/Navigator?Yak-List |
3 | Quote: | | style="color: blue; text-decoration: underline; ">http://www.matronics.com/Navigator?Yak-List |
4 | Quote: | | style="color: blue; text-decoration: underline; ">http://www.matronics.com/Navigator?Yak-List |
5 | Quote: | | style="color: blue; text-decoration: underline; ">http://www.matronics.com/Navigator?Yak-List |
6 | Quote: | | style="color: blue; text-decoration: underline; ">http://www.matronics.com/Navigator?Yak-List |
7 | Quote: | | style="color: blue; text-decoration: underline; ">http://www.matronics.com/Navigator?Yak-List |
8 | Quote: | | style="color: blue; text-decoration: underline; ">http://www.matronics.com/Navigator?Yak-List |
9 | Quote: | | blue; text-decoration: underline; ">http://forums.matronics.com |
0 | Quote: | | blue; text-decoration: underline; ">http://forums.matronics.com |
1 | Quote: | | blue; text-decoration: underline; ">http://forums.matronics.com |
2 | Quote: | | blue; text-decoration: underline; ">http://forums.matronics.com |
3 | Quote: | | blue; text-decoration: underline; ">http://forums.matronics.com |
4 | Quote: | | blue; text-decoration: underline; ">http://forums.matronics.com |
5 | Quote: | | blue; text-decoration: underline; ">http://forums.matronics.com |
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[quote][b]
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radiopicture
Joined: 23 Jun 2008
Posts: 263
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| Posted: Tue Oct 19, 2010 4:27 am Post subject: Engine failure in Yak-50 |
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There's a Carl Hayes article (on the M-14P.com website) that explains that for any damage at all to occur, a (torsional resistance) of 400 lb-ft (I think) must be encountered to cause damage. During a regular (gear-up) landing on pavement with the wood prop, only one-tenth of an inch of blade is shaved off per rotation, which gets nowhere near that force. On the other hand, if you hit something else more abruptly, the inertia of things on the accessory shafts will shear those shafts off or twist them out of sync. This is all paraphrased, so if you haven't read it, you should read Carl's article, which addresses all kinds of prop strikes.
On Oct 18, 2010, at 10:20 PM, Roger Kemp M.D. wrote:
| Quote: | Not sure but I think I heard that there is a design shear point in shaft. But, if that were so why would a prop strike not do the same.
So the answer is I do not know.
Doc
From: owner-yak-list-server(at)matronics.com (owner-yak-list-server(at)matronics.com) [mailto:owner-yak-list-server(at)matronics.com (owner-yak-list-server(at)matronics.com)] On Behalf Of Eric Wobschall
Sent: Monday, October 18, 2010 5:27 PM
To: yak-list(at)matronics.com (yak-list(at)matronics.com)
Subject: Re: Engine failure in Yak-50
No problem, Doc.
So what is it that caused it to shear? Is that a deliberate design to prevent the engine from twisting off it's mounts from prop momentum? Otherwise, you'd think there wouldn't be enough inertia to just break free like that.
On Oct 18, 2010, at 4:17 PM, Roger Kemp M.D. wrote:
Sorry Eric, I wrote my response before seeing that you had already seen Robs post.
Doc
From: owner-yak-list-server(at)matronics.com (owner-yak-list-server(at)matronics.com) [mailto:owner-yak-list-server(at)matronics.com (owner-yak-list-server(at)matronics.com)] On Behalf Of Eric Wobschall
Sent: Monday, October 18, 2010 1:47 PM
To: yak-list(at)matronics.com (yak-list(at)matronics.com)
Subject: Re: Engine failure in Yak-50
Engine seized with broken gearbox, too. Well, OK... so that's how, which surprises me. Having access to the failed engine certainly trumps speculation.
On Oct 18, 2010, at 11:47 AM, Richard Goode wrote:
For those interested in more details:
· As had been suggested, I am sure the oil pressure would have fallen as the pressure release valve became unscrewed.
· Andy says that he noticed the zero oil pressure pretty much at the same time as the prop (as one would expect) went into coarse pitch.
· The engine then actually kept going for 9/10 minutes without oil, which is quite impressive.
· Oil temperatures didn’t go up simply because there was no oil and so nothing to measure! This of course was the reason for the engine failure – because the pressure release valve had not been wire-locked, it unscrewed and fell out.
· However it then totally seized and this is what broke the gearbox – hence the propeller continuing to windmill with a seized engine.
· The extent of the seizure was such that it is impossible to remove most of the cylinders!
· I would expect the CHT to have risen a bit, but only because a small part of it is oil-cooled, but the vast majority of cooling is through air, and of course he was at very low power settings in order to preserve the engine.
· In terms of gear-up of gear-down, I am sure gear-up is the safest way, but also, will cause far less damage to the aircraft.
Richard Goode Aerobatics
Rhodds Farm
Lyonshall
Herefordshire
HR5 3LW
United Kingdom
Tel: +44 (0) 1544 340120
Fax: +44 (0) 1544 340129
www.russianaeros.com
01234567
89012345678901234567
8
|
[quote][b]
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mark.bitterlich(at)navy.m
Guest
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| Posted: Tue Oct 19, 2010 8:16 am Post subject: Engine failure in Yak-50 |
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Excuse me, but that is not accurate information when it comes to a YAK-50
Much more than a 1/10 of an inch gets shaved off on a YAK-50 that lands gear up. I think you might have misread the article (I did not read it myself), or he might have been talking about some other type of aircraft than a YAK-50.
A YAK-50 making a gear up landing will take about 10 or 12 INCHES off the prop (or more). I own one of these aircraft and there is no question about that.
Mark Bitterlich
________________________________
From: owner-yak-list-server(at)matronics.com on behalf of Eric Wobschall
Sent: Tue 10/19/2010 8:23 AM
To: yak-list(at)matronics.com
Subject: Re: Engine failure in Yak-50
There's a Carl Hayes article (on the M-14P.com website) that explains that for any damage at all to occur, a (torsional resistance) of 400 lb-ft (I think) must be encountered to cause damage. During a regular (gear-up) landing on pavement with the wood prop, only one-tenth of an inch of blade is shaved off per rotation, which gets nowhere near that force. On the other hand, if you hit something else more abruptly, the inertia of things on the accessory shafts will shear those shafts off or twist them out of sync. This is all paraphrased, so if you haven't read it, you should read Carl's article, which addresses all kinds of prop strikes.
On Oct 18, 2010, at 10:20 PM, Roger Kemp M.D. wrote:
Not sure but I think I heard that there is a design shear point in shaft. But, if that were so why would a prop strike not do the same.
So the answer is I do not know.
Doc
From: owner-yak-list-server(at)matronics.com [mailto:owner-yak-list-server(at)matronics.com] On Behalf Of Eric Wobschall
Sent: Monday, October 18, 2010 5:27 PM
To: yak-list(at)matronics.com
Subject: Re: Engine failure in Yak-50
No problem, Doc.
So what is it that caused it to shear? Is that a deliberate design to prevent the engine from twisting off it's mounts from prop momentum? Otherwise, you'd think there wouldn't be enough inertia to just break free like that.
On Oct 18, 2010, at 4:17 PM, Roger Kemp M.D. wrote:
Sorry Eric, I wrote my response before seeing that you had already seen Robs post.
Doc
From: owner-yak-list-server(at)matronics.com [mailto:owner-yak-list-server(at)matronics.com] On Behalf Of Eric Wobschall
Sent: Monday, October 18, 2010 1:47 PM
To: yak-list(at)matronics.com
Subject: Re: Engine failure in Yak-50
Engine seized with broken gearbox, too. Well, OK... so that's how, which surprises me. Having access to the failed engine certainly trumps speculation.
On Oct 18, 2010, at 11:47 AM, Richard Goode wrote:
For those interested in more details:
· As had been suggested, I am sure the oil pressure would have fallen as the pressure release valve became unscrewed.
· Andy says that he noticed the zero oil pressure pretty much at the same time as the prop (as one would expect) went into coarse pitch.
· The engine then actually kept going for 9/10 minutes without oil, which is quite impressive.
· Oil temperatures didn't go up simply because there was no oil and so nothing to measure! This of course was the reason for the engine failure - because the pressure release valve had not been wire-locked, it unscrewed and fell out.
· However it then totally seized and this is what broke the gearbox - hence the propeller continuing to windmill with a seized engine.
· The extent of the seizure was such that it is impossible to remove most of the cylinders!
· I would expect the CHT to have risen a bit, but only because a small part of it is oil-cooled, but the vast majority of cooling is through air, and of course he was at very low power settings in order to preserve the engine.
· In terms of gear-up of gear-down, I am sure gear-up is the safest way, but also, will cause far less damage to the aircraft.
Richard Goode Aerobatics
Rhodds Farm
Lyonshall
Herefordshire
HR5 3LW
United Kingdom
Tel: +44 (0) 1544 340120
Fax: +44 (0) 1544 340129
www.russianaeros.com <http://www.russianaeros.com/>
style="color: blue; text-decoration: underline; ">http://www.matronics.com/Navigator?Yak-List
blue; text-decoration: underline; ">http://forums.matronics.com <http://forums.matronics.com/>
style="color: blue; text-decoration: underline; ">http://www.matronics.com/contribution
http://www.matronics.com/Navigator?Yak-List
http://forums.matronics.com <http://forums.matronics.com/>
http://www.matronics.com/contribution
style="color: blue; text-decoration: underline; ">http://www.matronics.com/Navigator?Yak-List
blue; text-decoration: underline; ">http://forums.matronics.com <http://forums.matronics.com/>
style="color: blue; text-decoration: underline; ">http://www.matronics.com/contribution
http://www.matronics.com/Navigator?Yak-List
http://forums.matronics.com <http://forums.matronics.com/>
http://www.matronics.com/contribution
style="color: blue; text-decoration: underline; ">http://www.matronics.com/Navigator?Yak-List
blue; text-decoration: underline; ">http://forums.matronics.com
style="color: blue; text-decoration: underline; ">http://www.matronics.com/contribution
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richard.goode(at)russiana
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| Posted: Tue Oct 19, 2010 8:30 am Post subject: Engine failure in Yak-50 |
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Engine failure in Yak-50
It was the gearbox that broke up, allowing the propeller shaft to turn freely.
The M14P propeller shaft is incredibly strong, unlike Lycomings, which do have a certain tendency to shed propellers.
I have only heard of this happening once on a M14P, and that on a very hard flown Russian Team Sukhoi.
Richard Goode Aerobatics
Rhodds Farm
Lyonshall
Herefordshire
HR5 3LW
United Kingdom
Tel: +44 (0) 1544 340120
Fax: +44 (0) 1544 340129
www.russianaeros.com
[quote][b]
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pilko2(at)btinternet.com
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| Posted: Tue Oct 19, 2010 9:52 am Post subject: Engine failure in Yak-50 |
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And I'm looking across my office at a selection of unintentionally shortened
prop blades from that very same Yak 50 and concur at least 10 inches of "Oh
bugger" is involved !
kp
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ph451(at)yahoo.com
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| Posted: Tue Oct 19, 2010 10:31 am Post subject: Engine failure in Yak-50 |
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He said, per strike
--- On Tue, 10/19/10, Bitterlich, Mark G CIV Det Cherry Point, MALS-14 64E <mark.bitterlich(at)navy.mil> wrote:
| Quote: |
From: Bitterlich, Mark G CIV Det Cherry Point, MALS-14 64E <mark.bitterlich(at)navy.mil>
Subject: RE: Engine failure in Yak-50
To: yak-list(at)matronics.com
Date: Tuesday, October 19, 2010, 5:12 PM
--> Yak-List message posted by: "Bitterlich, Mark G CIV Det Cherry Point, MALS-14 64E" <mark.bitterlich(at)navy.mil (mark.bitterlich(at)navy.mil)>
Excuse me, but that is not accurate information when it comes to a YAK-50
Much more than a 1/10 of an inch gets shaved off on a YAK-50 that lands gear up. I think you might have misread the article (I did not read it myself), or he might have been talking about some other type of aircraft than a YAK-50.
A YAK-50 making a gear up landing will take about 10 or 12 INCHES off the prop (or more). I own one of these aircraft and there is no question about that.
Mark Bitterlich
________________________________
From: owner-yak-list-server(at)matronics.com (owner-yak-list-server(at)matronics.com) on behalf of Eric Wobschall
Sent: Tue 10/19/2010 8:23 AM
To: yak-list(at)matronics.com (yak-list(at)matronics.com)
Subject: Re: Engine failure in Yak-50
There's a Carl Hayes article (on the M-14P.com website) that explains that for any damage at all to occur, a (torsional resistance) of 400 lb-ft (I think) must be encountered to cause damage. During a regular (gear-up) landing on pavement with the wood prop, only one-tenth of an inch of blade is shaved off per rotation, which gets nowhere near that force. On the other hand, if you hit something else more abruptly, the inertia of things on the accessory shafts will shear those shafts off or twist them out of sync. This is all paraphrased, so if you haven't read it, you should read Carl's article, which addresses all kinds of prop strikes.
On Oct 18, 2010, at 10:20 PM, Roger Kemp M.D. wrote:
Not sure but I think I heard that there is a design shear point in shaft. But, if that were so why would a prop strike not do the same.
So the answer is I do not know.
Doc
From: owner-yak-list-server(at)matronics.com (owner-yak-list-server(at)matronics.com) [mailto:owner-yak-list-server(at)matronics.com (owner-yak-list-server(at)matronics.com)] On Behalf Of Eric Wobschall
Sent: Monday, October 18, 2010 5:27 PM
To: yak-list(at)matronics.com (yak-list(at)matronics.com)
Subject: Re: Engine failure in Yak-50
No problem, Doc.
So what is it that caused it to shear? Is that a deliberate design to prevent the engine from twisting off it's mounts from prop momentum? Otherwise, you'd think there wouldn't be enough inertia to just break free like that.
On Oct 18, 2010, at 4:17 PM, Roger Kemp M.D. wrote:
Sorry Eric, I wrote my response before seeing that you had already seen Robs post.
Doc
From: owner-yak-list-server(at)matronics.com (owner-yak-list-server(at)matronics.com) [mailto:owner-yak-list-server(at)matronics.com (owner-yak-list-server(at)matronics.com)] On Behalf Of Eric Wobschall
Sent: Monday, October 18, 2010 1:47 PM
To: yak-list(at)matronics.com (yak-list(at)matronics.com)
Subject: Re: Engine failure in Yak-50
Engine seized with broken gearbox, too. Well, OK... so that's how, which surprises me. Having access to the failed engine certainly trumps speculation.
On Oct 18, 2010, at 11:47 AM, Richard Goode wrote:
For those interested in more details:
· As had been suggested, I am sure the oil pressure would have fallen as the pressure release valve became unscrewed.
· Andy says that he noticed the zero oil pressure pretty much at the same time as the prop (as one would expect) went into coarse pitch.
· The engine then actually kept going for 9/10 minutes without oil, which is quite impressive.
· Oil temperatures didn't go up simply because there was no oil and so nothing to measure! This of course was the reason for the engine failure - because the pressure release valve had not been wire-locked, it unscrewed and fell out.
· However it then totally seized and this is what broke the gearbox - hence the propeller continuing to windmill with a seized engine.
· The extent of the seizure was such that it is impossible to remove most of the cylinders!
· I would expect the CHT to have risen a bit, but only because a small part of it is oil-cooled, but the vast majority of cooling is through air, and of course he was at very low power settings in order to preserve the engine.
· In terms of gear-up of gear-down, I am sure gear-up is the safest way, but also, will cause far less damage to the aircraft.
Richard Goode Aerobatics
Rhodds Farm
Lyonshall
Herefordshire
HR5 3LW
United Kingdom
Tel: +44 (0) 1544 340120
Fax: +44 (0) 1544 340129
www.russianaeros.com <http://www.russianaeros.com/>
style="color: blue; text-decoration: underline; ">http://www.matronics.com/Navigator?Yak-List
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viperdoc(at)mindspring.co
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| Posted: Tue Oct 19, 2010 10:48 am Post subject: Engine failure in Yak-50 |
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That is true. And if you have ever had the pleasure of watching someone doing a go round from a near gear up landing, it looks like a saw mill with all the saw dust flying. It may take a tenth of an inch per pass but at power up to go around it looks like a dust bowl for a heart beat.
No, I was not guilty! Also no names will be given to protect the guilty parties.
doc
From: owner-yak-list-server(at)matronics.com [mailto:owner-yak-list-server(at)matronics.com] On Behalf Of Paul Hamlin
Sent: Tuesday, October 19, 2010 1:28 PM
To: yak-list(at)matronics.com
Subject: RE: Engine failure in Yak-50
He said, per strike
--- On Tue, 10/19/10, Bitterlich, Mark G CIV Det Cherry Point, MALS-14 64E <mark.bitterlich(at)navy.mil> wrote:
From: Bitterlich, Mark G CIV Det Cherry Point, MALS-14 64E <mark.bitterlich(at)navy.mil>
Subject: RE: Engine failure in Yak-50
To: yak-list(at)matronics.com
Date: Tuesday, October 19, 2010, 5:12 PM
--> Yak-List message posted by: "Bitterlich, Mark G CIV Det Cherry Point, MALS-14 64E" <mark.bitterlich(at)navy.mil>
Excuse me, but that is not accurate information when it comes to a YAK-50
Much more than a 1/10 of an inch gets shaved off on a YAK-50 that lands gear up. I think you might have misread the article (I did not read it myself), or he might have been talking about some other type of aircraft than a YAK-50.
A YAK-50 making a gear up landing will take about 10 or 12 INCHES off the prop (or more). I own one of these aircraft and there is no question about that.
Mark Bitterlich
________________________________
From: owner-yak-list-server(at)matronics.com on behalf of Eric Wobschall
Sent: Tue 10/19/2010 8:23 AM
To: yak-list(at)matronics.com
Subject: Re: Engine failure in Yak-50
There's a Carl Hayes article (on the M-14P.com website) that explains that for any damage at all to occur, a (torsional resistance) of 400 lb-ft (I think) must be encountered to cause damage. During a regular (gear-up) landing on pavement with the wood prop, only one-tenth of an inch of blade is shaved off per rotation, which gets nowhere near that force. On the other hand, if you hit something else more abruptly, the inertia of things on the accessory shafts will shear those shafts off or twist them out of sync. This is all paraphrased, so if you haven't read it, you should read Carl's article, which addresses all kinds of prop strikes.
On Oct 18, 2010, at 10:20 PM, Roger Kemp M.D. wrote:
Not sure but I think I heard that there is a design shear point in shaft. But, if that were so why would a prop strike not do the same.
So the answer is I do not know.
Doc
From: owner-yak-list-server(at)matronics.com [mailto:owner-yak-list-server(at)matronics.com] On Behalf Of Eric Wobschall
Sent: Monday, October 18, 2010 5:27 PM
To: yak-list(at)matronics.com
Subject: Re: Engine failure in Yak-50
No problem, Doc.
So what is it that caused it to shear? Is that a deliberate design to prevent the engine from twisting off it's mounts from prop momentum? Otherwise, you'd think there wouldn't be enough inertia to just break free like that.
On Oct 18, 2010, at 4:17 PM, Roger Kemp M.D. wrote:
Sorry Eric, I wrote my response before seeing that you had already seen Robs post.
Doc
From: owner-yak-list-server(at)matronics.com [mailto:owner-yak-list-server(at)matronics.com] On Behalf Of Eric Wobschall
Sent: Monday, October 18, 2010 1:47 PM
To: yak-list(at)matronics.com
Subject: Re: Engine failure in Yak-50
Engine seized with broken gearbox, too. Well, OK... so that's how, which surprises me. Having access to the failed engine certainly trumps speculation.
On Oct 18, 2010, at 11:47 AM, Richard Goode wrote:
For those interested in more details:
· As had been suggested, I am sure the oil pressure would have fallen as the pressure release valve became unscrewed.
· Andy says that he noticed the zero oil pressure pretty much at the same time as the prop (as one would expect) went into coarse pitch.
· The engine then actually kept going for 9/10 minutes without oil, which is quite impressive.
· Oil temperatures didn't go up simply because there was no oil and so nothing to measure! This of course was the reason for the engine failure - because the pressure release valve had not been wire-locked, it unscrewed and fell out.
· However it then totally seized and this is what broke the gearbox - hence the propeller continuing to windmill with a seized engine.
· The extent of the seizure was such that it is impossible to remove most of the cylinders!
· I would expect the CHT to have risen a bit, but only because a small part of it is oil-cooled, but the vast majority of cooling is through air, and of course he was at very low power settings in order to preserve the engine.
· In terms of gear-up of gear-down, I am sure gear-up is the safest way, but also, will cause far less damage to the aircraft.
Richard Goode Aerobatics
Rhodds Farm
Lyonshall
Herefordshire
HR5 3LW
United Kingdom
Tel: +44 (0) 1544 340120
Fax: +44 (0) 1544 340129
www.russianaeros.com <http://www.russianaeros.com/>
style="color: blue; text-decoration: underline; ">http://www.matronics.com/Navigator?Yak-List
blue; text-decoration: underline; ">http://forums.matronics.com <http://forums.matronics.com/>
style="color: blue; text-decoration: underline; ">http://www.matronics.com/contribution
http://www.matronics.com/Navigator?Yak-List
http://forums.matronics.com <http://forums.matronics.com/>
http://www.matronics.com/contribution
style="color: blue; text-decoration: underline; ">http://www.matronics.com/Navigator?Yak-List
blue; text-decoration: underline; ">http://forums.matronics.com <http://forums.matronics.com/>
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viperdoc(at)mindspring.co
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| Posted: Tue Oct 19, 2010 11:07 am Post subject: Engine failure in Yak-50 |
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KP,
What's your next plane going to be? Another 50?
Doc
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mark.bitterlich(at)navy.m
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| Posted: Tue Oct 19, 2010 11:24 am Post subject: Engine failure in Yak-50 |
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You land gear up in a YAK-50 and I don't care how many 1/10's of an inch come off at a time, which of course has a lot to do with engine rpm, since rate, etc., I really don't understand the issue. There is a loud noise and then about 10 inches off of either end are gone. In some cases, the prop is in balance and can even be flown around the pattern. Amazing huh?
Mark Bitterlich
________________________________
From: owner-yak-list-server(at)matronics.com on behalf of Roger Kemp M.D.
Sent: Tue 10/19/2010 2:46 PM
To: yak-list(at)matronics.com
Subject: RE: Engine failure in Yak-50
That is true. And if you have ever had the pleasure of watching someone doing a go round from a near gear up landing, it looks like a saw mill with all the saw dust flying. It may take a tenth of an inch per pass but at power up to go around it looks like a dust bowl for a heart beat.
No, I was not guilty! Also no names will be given to protect the guilty parties.
doc
From: owner-yak-list-server(at)matronics.com [mailto:owner-yak-list-server(at)matronics.com] On Behalf Of Paul Hamlin
Sent: Tuesday, October 19, 2010 1:28 PM
To: yak-list(at)matronics.com
Subject: RE: Engine failure in Yak-50
He said, per strike
--- On Tue, 10/19/10, Bitterlich, Mark G CIV Det Cherry Point, MALS-14 64E <mark.bitterlich(at)navy.mil> wrote:
From: Bitterlich, Mark G CIV Det Cherry Point, MALS-14 64E <mark.bitterlich(at)navy.mil>
Subject: RE: Engine failure in Yak-50
To: yak-list(at)matronics.com
Date: Tuesday, October 19, 2010, 5:12 PM
Excuse me, but that is not accurate information when it comes to a YAK-50
Much more than a 1/10 of an inch gets shaved off on a YAK-50 that lands gear up. I think you might have misread the article (I did not read it myself), or he might have been talking about some other type of aircraft than a YAK-50.
A YAK-50 making a gear up landing will take about 10 or 12 INCHES off the prop (or more). I own one of these aircraft and there is no question about that.
Mark Bitterlich
________________________________
From: owner-yak-list-server(at)matronics.com <http://us.mc511.mail.yahoo.com/mc/compose?to=owner-yak-list-server(at)matronics.com> on behalf of Eric Wobschall
Sent: Tue 10/19/2010 8:23 AM
To: yak-list(at)matronics.com <http://us.mc511.mail.yahoo.com/mc/compose?to=yak-list(at)matronics.com>
Subject: Re: Engine failure in Yak-50
There's a Carl Hayes article (on the M-14P.com website) that explains that for any damage at all to occur, a (torsional resistance) of 400 lb-ft (I think) must be encountered to cause damage. During a regular (gear-up) landing on pavement with the wood prop, only one-tenth of an inch of blade is shaved off per rotation, which gets nowhere near that force. On the other hand, if you hit something else more abruptly, the inertia of things on the accessory shafts will shear those shafts off or twist them out of sync. This is all paraphrased, so if you haven't read it, you should read Carl's article, which addresses all kinds of prop strikes.
On Oct 18, 2010, at 10:20 PM, Roger Kemp M.D. wrote:
Not sure but I think I heard that there is a design shear point in shaft. But, if that were so why would a prop strike not do the same.
So the answer is I do not know.
Doc
From: owner-yak-list-server(at)matronics.com <http://us.mc511.mail.yahoo.com/mc/compose?to=owner-yak-list-server(at)matronics.com> [mailto:owner-yak-list-server(at)matronics.com <http://us.mc511.mail.yahoo.com/mc/compose?to=owner-yak-list-server(at)matronics.com> ] On Behalf Of Eric Wobschall
Sent: Monday, October 18, 2010 5:27 PM
To: yak-list(at)matronics.com <http://us.mc511.mail.yahoo.com/mc/compose?to=yak-list(at)matronics.com>
Subject: Re: Engine failure in Yak-50
No problem, Doc.
So what is it that caused it to shear? Is that a deliberate design to prevent the engine from twisting off it's mounts from prop momentum? Otherwise, you'd think there wouldn't be enough inertia to just break free like that.
On Oct 18, 2010, at 4:17 PM, Roger Kemp M.D. wrote:
Sorry Eric, I wrote my response before seeing that you had already seen Robs post.
Doc
From: owner-yak-list-server(at)matronics.com <http://us.mc511.mail.yahoo.com/mc/compose?to=owner-yak-list-server(at)matronics.com> [mailto:owner-yak-list-server(at)matronics.com <http://us.mc511.mail.yahoo.com/mc/compose?to=owner-yak-list-server(at)matronics.com> ] On Behalf Of Eric Wobschall
Sent: Monday, October 18, 2010 1:47 PM
To: yak-list(at)matronics.com <http://us.mc511.mail.yahoo.com/mc/compose?to=yak-list(at)matronics.com>
Subject: Re: Engine failure in Yak-50
Engine seized with broken gearbox, too. Well, OK... so that's how, which surprises me. Having access to the failed engine certainly trumps speculation.
On Oct 18, 2010, at 11:47 AM, Richard Goode wrote:
For those interested in more details:
· As had been suggested, I am sure the oil pressure would have fallen as the pressure release valve became unscrewed.
· Andy says that he noticed the zero oil pressure pretty much at the same time as the prop (as one would expect) went into coarse pitch.
· The engine then actually kept going for 9/10 minutes without oil, which is quite impressive.
· Oil temperatures didn't go up simply because there was no oil and so nothing to measure! This of course was the reason for the engine failure - because the pressure release valve had not been wire-locked, it unscrewed and fell out.
· However it then totally seized and this is what broke the gearbox - hence the propeller continuing to windmill with a seized engine.
· The extent of the seizure was such that it is impossible to remove most of the cylinders!
· I would expect the CHT to have risen a bit, but only because a small part of it is oil-cooled, but the vast majority of cooling is through air, and of course he was at very low power settings in order to preserve the engine.
· In terms of gear-up of gear-down, I am sure gear-up is the safest way, but also, will cause far less damage to the aircraft.
Richard Goode Aerobatics
Rhodds Farm
Lyonshall
Herefordshire
HR5 3LW
United Kingdom
Tel: +44 (0) 1544 340120
Fax: +44 (0) 1544 340129
www.russianaeros.com <http://www.russianaeros.com/>
style="color: blue; text-decoration: underline; ">http://www.matronics.com/Navigator?Yak-List
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mark.bitterlich(at)navy.m
Guest
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| Posted: Tue Oct 19, 2010 11:25 am Post subject: Engine failure in Yak-50 |
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Really? And exactly how was that determined? A 1000 frame per second camera focused on a YAK-50 performing a gear up landing?
Excuse me... ?
This is silly. You make an approach with the gear up in a 50, there is a loud buzz and before you can say WHAT THE F__K WAS THAT? You have 10 inches or more gone off each end of your prop.
Who cares if it came off 1/10th of an inch at a time? And I find that number to be variable on sink rate and engine RPM at the time, don't you think?
Mark Bitterlich
________________________________
From: owner-yak-list-server(at)matronics.com on behalf of Paul Hamlin
Sent: Tue 10/19/2010 2:28 PM
To: yak-list(at)matronics.com
Subject: RE: Engine failure in Yak-50
He said, per strike
--- On Tue, 10/19/10, Bitterlich, Mark G CIV Det Cherry Point, MALS-14 64E <mark.bitterlich(at)navy.mil> wrote:
From: Bitterlich, Mark G CIV Det Cherry Point, MALS-14 64E <mark.bitterlich(at)navy.mil>
Subject: RE: Engine failure in Yak-50
To: yak-list(at)matronics.com
Date: Tuesday, October 19, 2010, 5:12 PM
Excuse me, but that is not accurate information when it comes to a YAK-50
Much more than a 1/10 of an inch gets shaved off on a YAK-50 that lands gear up. I think you might have misread the article (I did not read it myself), or he might have been talking about some other type of aircraft than a YAK-50.
A YAK-50 making a gear up landing will take about 10 or 12 INCHES off the prop (or more). I own one of these aircraft and there is no question about that.
Mark Bitterlich
________________________________
From: owner-yak-list-server(at)matronics.com <http://us.mc511.mail.yahoo.com/mc/compose?to=owner-yak-list-server(at)matronics.com> on behalf of Eric Wobschall
Sent: Tue 10/19/2010 8:23 AM
To: yak-list(at)matronics.com <http://us.mc511.mail.yahoo.com/mc/compose?to=yak-list(at)matronics.com>
Subject: Re: Engine failure in Yak-50
There's a Carl Hayes article (on the M-14P.com website) that explains that for any damage at all to occur, a (torsional resistance) of 400 lb-ft (I think) must be encountered to cause damage. During a regular (gear-up) landing on pavement with the wood prop, only one-tenth of an inch of blade is shaved off per rotation, which gets nowhere near that force. On the other hand, if you hit something else more abruptly, the inertia of things on the accessory shafts will shear those shafts off or twist them out of sync. This is all paraphrased, so if you haven't read it, you should read Carl's article, which addresses all kinds of prop strikes.
On Oct 18, 2010, at 10:20 PM, Roger Kemp M.D. wrote:
Not sure but I think I heard that there is a design shear point in shaft. But, if that were so why would a prop strike not do the same.
So the answer is I do not know.
Doc
From: owner-yak-list-server(at)matronics.com <http://us.mc511.mail.yahoo.com/mc/compose?to=owner-yak-list-server(at)matronics.com> [mailto:owner-yak-list-server(at)matronics.com <http://us.mc511.mail.yahoo.com/mc/compose?to=owner-yak-list-server(at)matronics.com> ] On Behalf Of Eric Wobschall
Sent: Monday, October 18, 2010 5:27 PM
To: yak-list(at)matronics.com <http://us.mc511.mail.yahoo.com/mc/compose?to=yak-list(at)matronics.com>
Subject: Re: Engine failure in Yak-50
No problem, Doc.
So what is it that caused it to shear? Is that a deliberate design to prevent the engine from twisting off it's mounts from prop momentum? Otherwise, you'd think there wouldn't be enough inertia to just break free like that.
On Oct 18, 2010, at 4:17 PM, Roger Kemp M.D. wrote:
Sorry Eric, I wrote my response before seeing that you had already seen Robs post.
Doc
From: owner-yak-list-server(at)matronics.com <http://us.mc511.mail.yahoo.com/mc/compose?to=owner-yak-list-server(at)matronics.com> [mailto:owner-yak-list-server(at)matronics.com <http://us.mc511.mail.yahoo.com/mc/compose?to=owner-yak-list-server(at)matronics.com> ] On Behalf Of Eric Wobschall
Sent: Monday, October 18, 2010 1:47 PM
To: yak-list(at)matronics.com <http://us.mc511.mail.yahoo.com/mc/compose?to=yak-list(at)matronics.com>
Subject: Re: Engine failure in Yak-50
Engine seized with broken gearbox, too. Well, OK... so that's how, which surprises me. Having access to the failed engine certainly trumps speculation.
On Oct 18, 2010, at 11:47 AM, Richard Goode wrote:
For those interested in more details:
· As had been suggested, I am sure the oil pressure would have fallen as the pressure release valve became unscrewed.
· Andy says that he noticed the zero oil pressure pretty much at the same time as the prop (as one would expect) went into coarse pitch.
· The engine then actually kept going for 9/10 minutes without oil, which is quite impressive.
· Oil temperatures didn't go up simply because there was no oil and so nothing to measure! This of course was the reason for the engine failure - because the pressure release valve had not been wire-locked, it unscrewed and fell out.
· However it then totally seized and this is what broke the gearbox - hence the propeller continuing to windmill with a seized engine.
· The extent of the seizure was such that it is impossible to remove most of the cylinders!
· I would expect the CHT to have risen a bit, but only because a small part of it is oil-cooled, but the vast majority of cooling is through air, and of course he was at very low power settings in order to preserve the engine.
· In terms of gear-up of gear-down, I am sure gear-up is the safest way, but also, will cause far less damage to the aircraft.
Richard Goode Aerobatics
Rhodds Farm
Lyonshall
Herefordshire
HR5 3LW
United Kingdom
Tel: +44 (0) 1544 340120
Fax: +44 (0) 1544 340129
www.russianaeros.com <http://www.russianaeros.com/>
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ph451(at)yahoo.com
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| Posted: Tue Oct 19, 2010 11:56 am Post subject: Engine failure in Yak-50 |
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the point was about shearing shafts, if only a little at a time comes off at a time, not enough force to shear
ab
--- On Tue, 10/19/10, Bitterlich, Mark G CIV Det Cherry Point, MALS-14 64E <mark.bitterlich(at)navy.mil> wrote:
| Quote: |
From: Bitterlich, Mark G CIV Det Cherry Point, MALS-14 64E <mark.bitterlich(at)navy.mil>
Subject: RE: Engine failure in Yak-50
To: yak-list(at)matronics.com
Date: Tuesday, October 19, 2010, 8:17 PM
--> Yak-List message posted by: "Bitterlich, Mark G CIV Det Cherry Point, MALS-14 64E" <mark.bitterlich(at)navy.mil (mark.bitterlich(at)navy.mil)>
Really? And exactly how was that determined? A 1000 frame per second camera focused on a YAK-50 performing a gear up landing?
Excuse me... ?
This is silly. You make an approach with the gear up in a 50, there is a loud buzz and before you can say WHAT THE F__K WAS THAT? You have 10 inches or more gone off each end of your prop.
Who cares if it came off 1/10th of an inch at a time? And I find that number to be variable on sink rate and engine RPM at the time, don't you think?
Mark Bitterlich
________________________________
From: owner-yak-list-server(at)matronics.com (owner-yak-list-server(at)matronics.com) on behalf of Paul Hamlin
Sent: Tue 10/19/2010 2:28 PM
To: yak-list(at)matronics.com (yak-list(at)matronics.com)
Subject: RE: Engine failure in Yak-50
He said, per strike
--- On Tue, 10/19/10, Bitterlich, Mark G CIV Det Cherry Point, MALS-14 64E <mark.bitterlich(at)navy.mil (mark.bitterlich(at)navy.mil)> wrote:
From: Bitterlich, Mark G CIV Det Cherry Point, MALS-14 64E <mark.bitterlich(at)navy.mil (mark.bitterlich(at)navy.mil)>
Subject: RE: Engine failure in Yak-50
To: yak-list(at)matronics.com (yak-list(at)matronics.com)
Date: Tuesday, October 19, 2010, 5:12 PM
--> Yak-List message posted by: "Bitterlich, Mark G CIV Det Cherry Point, MALS-14 64E" <mark.bitterlich(at)navy.mil (mark.bitterlich(at)navy.mil) <http://us.mc511.mail.yahoo.com/mc/compose?to=mark.bitterlich(at)navy.mil> >
Excuse me, but that is not accurate information when it comes to a YAK-50
Much more than a 1/10 of an inch gets shaved off on a YAK-50 that lands gear up. I think you might have misread the article (I did not read it myself), or he might have been talking about some other type of aircraft than a YAK-50.
A YAK-50 making a gear up landing will take about 10 or 12 INCHES off the prop (or more). I own one of these aircraft and there is no question about that.
Mark Bitterlich
________________________________
From: owner-yak-list-server(at)matronics.com (owner-yak-list-server(at)matronics.com) <http://us.mc511.mail.yahoo.com/mc/compose?to=owner-yak-list-server(at)matronics.com> on behalf of Eric Wobschall
Sent: Tue 10/19/2010 8:23 AM
To: yak-list(at)matronics.com (yak-list(at)matronics.com) <http://us.mc511.mail.yahoo.com/mc/compose?to=yak-list(at)matronics.com>
Subject: Re: Engine failure in Yak-50
There's a Carl Hayes article (on the M-14P.com website) that explains that for any damage at all to occur, a (torsional resistance) of 400 lb-ft (I think) must be encountered to cause damage. During a regular (gear-up) landing on pavement with the wood prop, only one-tenth of an inch of blade is shaved off per rotation, which gets nowhere near that force. On the other hand, if you hit something else more abruptly, the inertia of things on the accessory shafts will shear those shafts off or twist them out of sync. This is all paraphrased, so if you haven't read it, you should read Carl's article, which addresses all kinds of prop strikes.
On Oct 18, 2010, at 10:20 PM, Roger Kemp M.D. wrote:
Not sure but I think I heard that there is a design shear point in shaft. But, if that were so why would a prop strike not do the same.
So the answer is I do not know.
Doc
From: owner-yak-list-server(at)matronics.com (owner-yak-list-server(at)matronics.com) <owner-yak-list-server(at)matronics.com (owner-yak-list-server(at)matronics.com) <http://us.mc511.mail.yahoo.com/mc/compose?to=owner-yak-list-server(at)matronics.com> ] On Behalf Of Eric Wobschall
Sent: Monday, October 18, 2010 5:27 PM
To: yak-list(at)matronics.com (yak-list(at)matronics.com) <http://us.mc511.mail.yahoo.com/mc/compose?to=yak-list(at)matronics.com>
Subject: Re: Engine failure in Yak-50
No problem, Doc.
So what is it that caused it to shear? Is that a deliberate design to prevent the engine from twisting off it's mounts from prop momentum? Otherwise, you'd think there wouldn't be enough inertia to just break free like that.
On Oct 18, 2010, at 4:17 PM, Roger Kemp M.D. wrote:
Sorry Eric, I wrote my response before seeing that you had already seen Robs post.
Doc
From: owner-yak-list-server(at)matronics.com (owner-yak-list-server(at)matronics.com) <owner-yak-list-server(at)matronics.com (owner-yak-list-server(at)matronics.com) <http://us.mc511.mail.yahoo.com/mc/compose?to=owner-yak-list-server(at)matronics.com> ] On Behalf Of Eric Wobschall
Sent: Monday, October 18, 2010 1:47 PM
To: yak-list(at)matronics.com (yak-list(at)matronics.com) <http://us.mc511.mail.yahoo.com/mc/compose?to=yak-list(at)matronics.com>
Subject: Re: Engine failure in Yak-50
Engine seized with broken gearbox, too. Well, OK... so that's how, which surprises me. Having access to the failed engine certainly trumps speculation.
On Oct 18, 2010, at 11:47 AM, Richard Goode wrote:
For those interested in more details:
· As had been suggested, I am sure the oil pressure would have fallen as the pressure release valve became unscrewed.
· Andy says that he noticed the zero oil pressure pretty much at the same time as the prop (as one would expect) went into coarse pitch.
· The engine then actually kept going for 9/10 minutes without oil, which is quite impressive.
· Oil temperatures didn't go up simply because there was no oil and so nothing to measure! This of course was the reason for the engine failure - because the pressure release valve had not been wire-locked, it unscrewed and fell out.
· However it then totally seized and this is what broke the gearbox - hence the propeller continuing to windmill with a seized engine.
· The extent of the seizure was such that it is impossible to remove most of the cylinders!
· I would expect the CHT to have risen a bit, but only because a small part of it is oil-cooled, but the vast majority of cooling is through air, and of course he was at very low power settings in order to preserve the engine.
· In terms of gear-up of gear-down, I am sure gear-up is the safest way, but also, will cause far less damage to the aircraft.
Richard Goode Aerobatics
Rhodds Farm
Lyonshall
Herefordshire
HR5 3LW
United Kingdom
Tel: +44 (0) 1544 340120
Fax: +44 (0) 1544 340129
www.russianaeros.com <http://www.russianaeros.com/>
style="color: blue; text-decoration: underline; ">http://www.matronics.com/Navigator?Yak-List
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mark.bitterlich(at)navy.m
Guest
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| Posted: Tue Oct 19, 2010 12:42 pm Post subject: Engine failure in Yak-50 |
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The point is that it does not come off 1/10 inch at a time folks. I was there, I watched it, I have the fragments, and they are not tiny little 1/10" pieces of dust. The prop is made out of WOOD folks. WOOD. When you whack it into a concrete runway it splinters just like you hit it with a hatchet. The reason there is not enough force to shear steel is because last time I checked, steel is a whole lot harder than compressed wood with a fiberglass sheath.
Sorry for blowing a little steam here but how many of you commenting on this subject matter have actually seen a YAK-50 prop hit the ground with the gear up?
How many of you have what is left of that prop in your hangar?
How many of you went out on the runway and actually picked up the pieces?
So, if you want to continue to tell me that I simply don't know what I am talking about since you read a good article someplace else on the Internet, you just go right ahead on with your bad self!
Lastly, even though the prop is made out of wood, and even though it comes apart like an attack with a chainsaw, the force DOES have the ability to cause damage to the M-14 engine, to areas that you can go back on this list and read about from people like Richard Goode if you would like.
In the case of THIS engine failure, when the engine seized (and it DID seize), the spinning mass of the prop assembly was enough to cause failure in the gearbox allowing the prop to continue to spin. That comes from the gent who took it apart.
Have a nice day.
Mark Bitterlich
From: Paul Hamlin
Sent: Tue 10/19/2010 3:54 PM
To: yak-list(at)matronics.com
Subject: RE: Engine failure in Yak-50
the point was about shearing shafts, if only a little at a time comes off at a time, not enough force to shear
ab
--- On Tue, 10/19/10, Bitterlich, Mark G CIV Det Cherry Point, MALS-14 64E <mark.bitterlich(at)navy.mil> wrote:
| Quote: |
From: Bitterlich, Mark G CIV Det Cherry Point, MALS-14 64E <mark.bitterlich(at)navy.mil>
Subject: RE: Engine failure in Yak-50
To: yak-list(at)matronics.com
Date: Tuesday, October 19, 2010, 8:17 PM
--> Yak-List message posted by: "Bitterlich, Mark G CIV Det Cherry Point, MALS-14 64E" <http://us.mc511.mail.yahoo.com/mc/compose?to=mark.bitterlich(at)navy.mil (mark.bitterlich(at)navy.mil)>
Really? And exactly how was that determined? A 1000 frame per second camera focused on a YAK-50 performing a gear up landing?
Excuse me... ?
This is silly. You make an approach with the gear up in a 50, there is a loud buzz and before you can say WHAT THE F__K WAS THAT? You have 10 inches or more gone off each end of your prop.
Who cares if it came off 1/10th of an inch at a time? And I find that number to be variable on sink rate and engine RPM at the time, don't you think?
Mark Bitterlich
________________________________
From: http://us.mc511.mail.yahoo.com/mc/compose?to=owner-yak-list-server(at)matronics.com (owner-yak-list-server(at)matronics.com) on behalf of Paul Hamlin
Sent: Tue 10/19/2010 2:28 PM
To: http://us.mc511.mail.yahoo.com/mc/compose?to=yak-list(at)matronics.com (yak-list(at)matronics.com)
Subject: RE: Engine failure in Yak-50
He said, per strike
--- On Tue, 10/19/10, Bitterlich, Mark G CIV Det Cherry Point, MALS-14 64E <http://us.mc511.mail.yahoo.com/mc/compose?to=mark.bitterlich(at)navy.mil (mark.bitterlich(at)navy.mil)> wrote:
From: Bitterlich, Mark G CIV Det Cherry Point, MALS-14 64E <http://us.mc511.mail.yahoo.com/mc/compose?to=mark.bitterlich(at)navy.mil (mark.bitterlich(at)navy.mil)>
Subject: RE: Engine failure in Yak-50
To: http://us.mc511.mail.yahoo.com/mc/compose?to=yak-list(at)matronics.com (yak-list(at)matronics.com)
Date: Tuesday, October 19, 2010, 5:12 PM
--> Yak-List message posted by: "Bitterlich, Mark G CIV Det Cherry Point, MALS-14 64E" <http://us.mc511.mail.yahoo.com/mc/compose?to=mark.bitterlich(at)navy.mil (mark.bitterlich(at)navy.mil) <http://us.mc511.mail.yahoo.com/mc/compose?to=mark.bitterlich(at)navy.mil> >
Excuse me, but that is not accurate information when it comes to a YAK-50
Much more than a 1/10 of an inch gets shaved off on a YAK-50 that lands gear up. I think you might have misread the article (I did not read it myself), or he might have been talking about some other type of aircraft than a YAK-50.
A YAK-50 making a gear up landing will take about 10 or 12 INCHES off the prop (or more). I own one of these aircraft and there is no question about that.
Mark Bitterlich
________________________________
From: http://us.mc511.mail.yahoo.com/mc/compose?to=owner-yak-list-server(at)matronics.com (owner-yak-list-server(at)matronics.com) <http://us.mc511.mail.yahoo.com/mc/compose?to=owner-yak-list-server(at)matronics.com> on behalf of Eric Wobschall
Sent: Tue 10/19/2010 8:23 AM
To: http://us.mc511.mail.yahoo.com/mc/compose?to=yak-list(at)matronics.com (yak-list(at)matronics.com) <http://us.mc511.mail.yahoo.com/mc/compose?to=yak-list(at)matronics.com>
Subject: Re: Engine failure in Yak-50
There's a Carl Hayes article (on the M-14P.com website) that explains that for any damage at all to occur, a (torsional resistance) of 400 lb-ft (I think) must be encountered to cause damage. During a regular (gear-up) landing on pavement with the wood prop, only one-tenth of an inch of blade is shaved off per rotation, which gets nowhere near that force. On the other hand, if you hit something else more abruptly, the inertia of things on the accessory shafts will shear those shafts off or twist them out of sync. This is all paraphrased, so if you haven't read it, you should read Carl's article, which addresses all kinds of prop strikes.
On Oct 18, 2010, at 10:20 PM, Roger Kemp M.D. wrote:
Not sure but I think I heard that there is a design shear point in shaft. But, if that were so why would a prop strike not do the same.
So the answer is I do not know.
Doc
From: http://us.mc511.mail.yahoo.com/mc/compose?to=owner-yak-list-server(at)matronics.com (owner-yak-list-server(at)matronics.com) <http://us.mc511.mail.yahoo.com/mc/compose?to=owner-yak-list-server(at)matronics.com (owner-yak-list-server(at)matronics.com) <http://us.mc511.mail.yahoo.com/mc/compose?to=owner-yak-list-server(at)matronics.com> ] On Behalf Of Eric Wobschall
Sent: Monday, October 18, 2010 5:27 PM
To: http://us.mc511.mail.yahoo.com/mc/compose?to=yak-list(at)matronics.com (yak-list(at)matronics.com) <http://us.mc511.mail.yahoo.com/mc/compose?to=yak-list(at)matronics.com>
Subject: Re: Engine failure in Yak-50
No problem, Doc.
So what is it that caused it to shear? Is that a deliberate design to prevent the engine from twisting off it's mounts from prop momentum? Otherwise, you'd think there wouldn't be enough inertia to just break free like that.
On Oct 18, 2010, at 4:17 PM, Roger Kemp M.D. wrote:
Sorry Eric, I wrote my response before seeing that you had already seen Robs post.
Doc
From: http://us.mc511.mail.yahoo.com/mc/compose?to=owner-yak-list-server(at)matronics.com (owner-yak-list-server(at)matronics.com) <http://us.mc511.mail.yahoo.com/mc/compose?to=owner-yak-list-server(at)matronics.com (owner-yak-list-server(at)matronics.com) <http://us.mc511.mail.yahoo.com/mc/compose?to=owner-yak-list-server(at)matronics.com> ] On Behalf Of Eric Wobschall
Sent: Monday, October 18, 2010 1:47 PM
To: http://us.mc511.mail.yahoo.com/mc/compose?to=yak-list(at)matronics.com (yak-list(at)matronics.com) <http://us.mc511.mail.yahoo.com/mc/compose?to=yak-list(at)matronics.com>
Subject: Re: Yak-List: Engine failure in Yak-50
Engine seized with broken gearbox, too. Well, OK... so that's how, which surprises me. Having access to the failed engine certainly trumps speculation.
On Oct 18, 2010, at 11:47 AM, Richard Goode wrote:
For those interested in more details:
· As had been suggested, I am sure the oil pressure would have fallen as the pressure release valve became unscrewed.
· Andy says that he noticed the zero oil pressure pretty much at the same time as the prop (as one would expect) went into coarse pitch.
· The engine then actually kept going for 9/10 minutes without oil, which is quite impressive.
· Oil temperatures didn't go up simply because there was no oil and so nothing to measure! This of course was the reason for the engine failure - because the pressure release valve had not been wire-locked, it unscrewed and fell out.
· However it then totally seized and this is what broke the gearbox - hence the propeller continuing to windmill with a seized engine.
· The extent of the seizure was such that it is impossible to remove most of the cylinders!
· I would expect the CHT to have risen a bit, but only because a small part of it is oil-cooled, but the vast majority of cooling is through air, and of course he was at very low power settings in order to preserve the engine.
· In terms of gear-up of gear-down, I am sure gear-up is the safest way, but also, will cause far less damage to the aircraft.
Richard Goode Aerobatics
Rhodds Farm
Lyonshall
Herefordshire
HR5 3LW
United Kingdom
Tel: +44 (0) 1544 340120
Fax: +44 (0) 1544 340129
www.russianaeros.com <http://www.russianaeros.com/>
style="color: blue; text-decoration: underline; ">http://www.matronics.com/Navigator?Yak-List
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f4ffm2(at)roadrunner.com
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| Posted: Tue Oct 19, 2010 2:23 pm Post subject: Engine failure in Yak-50 |
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Mark,
For what it's worth, some of us "lurkers" out here have seen a V530 prop smite the earth and we do know what a disaster it is.
A pal of ours, for whatever reason, collapsed the nose gear (but not the mains) of a 52 on landing. The rate of sink of the nose after the gear broke was quite high (the tail would have had quite a high rate of climb for a short while, as well) and the nose hit the runway with a great thumping noise.
I suspect that it is hard to imagine for those who haven't seen it, what a violent result this creates with the prop. It was as if the prop exploded. The shank and a few inches of the blades were recognizable...the remaining wood still attached to what had been the blades was more like shreds of wood fiber from a cellulose factory than anything else. Sizable shards of prop wood were scattered over a 50+ foot area.
It may be that this situation had a higher sink rate than the usual gear up incident. However, it is certain that a V530 prop can dismantle itself very quickly, and in spectacular fashion
Not what I read about, but what I saw. For insurance reasons, we weren't able to open up the engine, but I imagine that the content of the nose case was mush.
BR,
Roger Baker
On Oct 19, 2010, at 1:40 PM, Bitterlich, Mark G CIV Det Cherry Point, MALS-14 64E wrote:
[quote] The point is that it does not come off 1/10 inch at a time folks. I was there, I watched it, I have the fragments, and they are not tiny little 1/10" pieces of dust. The prop is made out of WOOD folks. WOOD. When you whack it into a concrete runway it splinters just like you hit it with a hatchet. The reason there is not enough force to shear steel is because last time I checked, steel is a whole lot harder than compressed wood with a fiberglass sheath.
Sorry for blowing a little steam here but how many of you commenting on this subject matter have actually seen a YAK-50 prop hit the ground with the gear up?
How many of you have what is left of that prop in your hangar?
How many of you went out on the runway and actually picked up the pieces?
So, if you want to continue to tell me that I simply don't know what I am talking about since you read a good article someplace else on the Internet, you just go right ahead on with your bad self!
Lastly, even though the prop is made out of wood, and even though it comes apart like an attack with a chainsaw, the force DOES have the ability to cause damage to the M-14 engine, to areas that you can go back on this list and read about from people like Richard Goode if you would like.
In the case of THIS engine failure, when the engine seized (and it DID seize), the spinning mass of the prop assembly was enough to cause failure in the gearbox allowing the prop to continue to spin. That comes from the gent who took it apart.
Have a nice day.
Mark Bitterlich
From: Paul Hamlin
Sent: Tue 10/19/2010 3:54 PM
To: yak-list(at)matronics.com (yak-list(at)matronics.com)
Subject: RE: Engine failure in Yak-50
the point was about shearing shafts, if only a little at a time comes off at a time, not enough force to shear
ab
--- On Tue, 10/19/10, Bitterlich, Mark G CIV Det Cherry Point, MALS-14 64E <mark.bitterlich(at)navy.mil (mark.bitterlich(at)navy.mil)> wrote:
| Quote: |
From: Bitterlich, Mark G CIV Det Cherry Point, MALS-14 64E <mark.bitterlich(at)navy.mil (mark.bitterlich(at)navy.mil)>
Subject: RE: Engine failure in Yak-50
To: yak-list(at)matronics.com (yak-list(at)matronics.com)
Date: Tuesday, October 19, 2010, 8:17 PM
--> Yak-List message posted by: "Bitterlich, Mark G CIV Det Cherry Point, MALS-14 64E" <http://us.mc511.mail.yahoo.com/mc/compose?to=mark.bitterlich(at)navy.mil (mark.bitterlich(at)navy.mil)>
Really? And exactly how was that determined? A 1000 frame per second camera focused on a YAK-50 performing a gear up landing?
Excuse me... ?
This is silly. You make an approach with the gear up in a 50, there is a loud buzz and before you can say WHAT THE F__K WAS THAT? You have 10 inches or more gone off each end of your prop.
Who cares if it came off 1/10th of an inch at a time? And I find that number to be variable on sink rate and engine RPM at the time, don't you think?
Mark Bitterlich
________________________________
From: http://us.mc511.mail.yahoo.com/mc/compose?to=owner-yak-list-server(at)matronics.com (owner-yak-list-server(at)matronics.com) on behalf of Paul Hamlin
Sent: Tue 10/19/2010 2:28 PM
To: http://us.mc511.mail.yahoo.com/mc/compose?to=yak-list(at)matronics.com (yak-list(at)matronics.com)
Subject: RE: Engine failure in Yak-50
He said, per strike
--- On Tue, 10/19/10, Bitterlich, Mark G CIV Det Cherry Point, MALS-14 64E <http://us.mc511.mail.yahoo.com/mc/compose?to=mark.bitterlich(at)navy.mil (mark.bitterlich(at)navy.mil)> wrote:
From: Bitterlich, Mark G CIV Det Cherry Point, MALS-14 64E <http://us.mc511.mail.yahoo.com/mc/compose?to=mark.bitterlich(at)navy.mil (mark.bitterlich(at)navy.mil)>
Subject: RE: Engine failure in Yak-50
To: http://us.mc511.mail.yahoo.com/mc/compose?to=yak-list(at)matronics.com (yak-list(at)matronics.com)
Date: Tuesday, October 19, 2010, 5:12 PM
--> Yak-List message posted by: "Bitterlich, Mark G CIV Det Cherry Point, MALS-14 64E" <http://us.mc511.mail.yahoo.com/mc/compose?to=mark.bitterlich(at)navy.mil (mark.bitterlich(at)navy.mil) <http://us.mc511.mail.yahoo.com/mc/compose?to=mark.bitterlich(at)navy.mil> >
Excuse me, but that is not accurate information when it comes to a YAK-50
Much more than a 1/10 of an inch gets shaved off on a YAK-50 that lands gear up. I think you might have misread the article (I did not read it myself), or he might have been talking about some other type of aircraft than a YAK-50.
A YAK-50 making a gear up landing will take about 10 or 12 INCHES off the prop (or more). I own one of these aircraft and there is no question about that.
Mark Bitterlich
________________________________
From: http://us.mc511.mail.yahoo.com/mc/compose?to=owner-yak-list-server(at)matronics.com (owner-yak-list-server(at)matronics.com) <http://us.mc511.mail.yahoo.com/mc/compose?to=owner-yak-list-server(at)matronics.com> on behalf of Eric Wobschall
Sent: Tue 10/19/2010 8:23 AM
To: http://us.mc511.mail.yahoo.com/mc/compose?to=yak-list(at)matronics.com (yak-list(at)matronics.com) <http://us.mc511.mail.yahoo.com/mc/compose?to=yak-list(at)matronics.com>
Subject: Re: Engine failure in Yak-50
There's a Carl Hayes article (on the M-14P.com website) that explains that for any damage at all to occur, a (torsional resistance) of 400 lb-ft (I think) must be encountered to cause damage. During a regular (gear-up) landing on pavement with the wood prop, only one-tenth of an inch of blade is shaved off per rotation, which gets nowhere near that force. On the other hand, if you hit something else more abruptly, the inertia of things on the accessory shafts will shear those shafts off or twist them out of sync. This is all paraphrased, so if you haven't read it, you should read Carl's article, which addresses all kinds of prop strikes.
On Oct 18, 2010, at 10:20 PM, Roger Kemp M.D. wrote:
Not sure but I think I heard that there is a design shear point in shaft. But, if that were so why would a prop strike not do the same.
So the answer is I do not know.
Doc
From: http://us.mc511.mail.yahoo.com/mc/compose?to=owner-yak-list-server(at)matronics.com (owner-yak-list-server(at)matronics.com) <http://us.mc511.mail.yahoo.com/mc/compose?to=owner-yak-list-server(at)matronics.com (owner-yak-list-server(at)matronics.com) <http://us.mc511.mail.yahoo.com/mc/compose?to=owner-yak-list-server(at)matronics.com> ] On Behalf Of Eric Wobschall
Sent: Monday, October 18, 2010 5:27 PM
To: http://us.mc511.mail.yahoo.com/mc/compose?to=yak-list(at)matronics.com (yak-list(at)matronics.com) <http://us.mc511.mail.yahoo.com/mc/compose?to=yak-list(at)matronics.com>
Subject: Re: Engine failure in Yak-50
No problem, Doc.
So what is it that caused it to shear? Is that a deliberate design to prevent the engine from twisting off it's mounts from prop momentum? Otherwise, you'd think there wouldn't be enough inertia to just break free like that.
On Oct 18, 2010, at 4:17 PM, Roger Kemp M.D. wrote:
Sorry Eric, I wrote my response before seeing that you had already seen Robs post.
Doc
From: http://us.mc511.mail.yahoo.com/mc/compose?to=owner-yak-list-server(at)matronics.com (owner-yak-list-server(at)matronics.com) <http://us.mc511.mail.yahoo.com/mc/compose?to=owner-yak-list-server(at)matronics.com (owner-yak-list-server(at)matronics.com) <http://us.mc511.mail.yahoo.com/mc/compose?to=owner-yak-list-server(at)matronics.com> ] On Behalf Of Eric Wobschall
Sent: Monday, October 18, 2010 1:47 PM
To: http://us.mc511.mail.yahoo.com/mc/compose?to=yak-list(at)matronics.com (yak-list(at)matronics.com) <http://us.mc511.mail.yahoo.com/mc/compose?to=yak-list(at)matronics.com>
Subject: Re: Engine failure in Yak-50
Engine seized with broken gearbox, too. Well, OK... so that's how, which surprises me. Having access to the failed engine certainly trumps speculation.
On Oct 18, 2010, at 11:47 AM, Richard Goode wrote:
For those interested in more details:
· As had been suggested, I am sure the oil pressure would have fallen as the pressure release valve became unscrewed.
· Andy says that he noticed the zero oil pressure pretty much at the same time as the prop (as one would expect) went into coarse pitch.
· The engine then actually kept going for 9/10 minutes without oil, which is quite impressive.
· Oil temperatures didn't go up simply because there was no oil and so nothing to measure! This of course was the reason for the engine failure - because the pressure release valve had not been wire-locked, it unscrewed and fell out.
· However it then totally seized and this is what broke the gearbox - hence the propeller continuing to windmill with a seized engine.
· The extent of the seizure was such that it is impossible to remove most of the cylinders!
· I would expect the CHT to have risen a bit, but only because a small part of it is oil-cooled, but the vast majority of cooling is through air, and of course he was at very low power settings in order to preserve the engine.
· In terms of gear-up of gear-down, I am sure gear-up is the safest way, but also, will cause far less damage to the aircraft.
Richard Goode Aerobatics
Rhodds Farm
Lyonshall
Herefordshire
HR5 3LW
United Kingdom
Tel: +44 (0) 1544 340120
Fax: +44 (0) 1544 340129
www.russianaeros.com <http://www.russianaeros.com/>
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mark.bitterlich(at)navy.m
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| Posted: Tue Oct 19, 2010 4:05 pm Post subject: Engine failure in Yak-50 |
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Concur.
Thanks for writing.
Mark
From: Roger Baker
Sent: Tue 10/19/2010 6:19 PM
To: yak-list(at)matronics.com
Subject: Re: Engine failure in Yak-50
Mark,
For what it's worth, some of us "lurkers" out here have seen a V530 prop smite the earth and we do know what a disaster it is.
A pal of ours, for whatever reason, collapsed the nose gear (but not the mains) of a 52 on landing. The rate of sink of the nose after the gear broke was quite high (the tail would have had quite a high rate of climb for a short while, as well) and the nose hit the runway with a great thumping noise.
I suspect that it is hard to imagine for those who haven't seen it, what a violent result this creates with the prop. It was as if the prop exploded. The shank and a few inches of the blades were recognizable...the remaining wood still attached to what had been the blades was more like shreds of wood fiber from a cellulose factory than anything else. Sizable shards of prop wood were scattered over a 50+ foot area.
It may be that this situation had a higher sink rate than the usual gear up incident. However, it is certain that a V530 prop can dismantle itself very quickly, and in spectacular fashion
Not what I read about, but what I saw. For insurance reasons, we weren't able to open up the engine, but I imagine that the content of the nose case was mush.
BR,
Roger Baker
On Oct 19, 2010, at 1:40 PM, Bitterlich, Mark G CIV Det Cherry Point, MALS-14 64E wrote:
| Quote: | The point is that it does not come off 1/10 inch at a time folks. I was there, I watched it, I have the fragments, and they are not tiny little 1/10" pieces of dust. The prop is made out of WOOD folks. WOOD. When you whack it into a concrete runway it splinters just like you hit it with a hatchet. The reason there is not enough force to shear steel is because last time I checked, steel is a whole lot harder than compressed wood with a fiberglass sheath.
Sorry for blowing a little steam here but how many of you commenting on this subject matter have actually seen a YAK-50 prop hit the ground with the gear up?
How many of you have what is left of that prop in your hangar?
How many of you went out on the runway and actually picked up the pieces?
So, if you want to continue to tell me that I simply don't know what I am talking about since you read a good article someplace else on the Internet, you just go right ahead on with your bad self!
Lastly, even though the prop is made out of wood, and even though it comes apart like an attack with a chainsaw, the force DOES have the ability to cause damage to the M-14 engine, to areas that you can go back on this list and read about from people like Richard Goode if you would like.
In the case of THIS engine failure, when the engine seized (and it DID seize), the spinning mass of the prop assembly was enough to cause failure in the gearbox allowing the prop to continue to spin. That comes from the gent who took it apart.
Have a nice day.
Mark Bitterlich
From: Paul Hamlin
Sent: Tue 10/19/2010 3:54 PM
To: yak-list(at)matronics.com (yak-list(at)matronics.com)
Subject: RE: Engine failure in Yak-50
the point was about shearing shafts, if only a little at a time comes off at a time, not enough force to shear
ab
--- On Tue, 10/19/10, Bitterlich, Mark G CIV Det Cherry Point, MALS-14 64E <mark.bitterlich(at)navy.mil (mark.bitterlich(at)navy.mil)> wrote:
| Quote: |
From: Bitterlich, Mark G CIV Det Cherry Point, MALS-14 64E <mark.bitterlich(at)navy.mil (mark.bitterlich(at)navy.mil)>
Subject: RE: Engine failure in Yak-50
To: yak-list(at)matronics.com (yak-list(at)matronics.com)
Date: Tuesday, October 19, 2010, 8:17 PM
--> Yak-List message posted by: "Bitterlich, Mark G CIV Det Cherry Point, MALS-14 64E" <http://us.mc511.mail.yahoo.com/mc/compose?to=mark.bitterlich(at)navy.mil (mark.bitterlich(at)navy.mil)>
Really? And exactly how was that determined? A 1000 frame per second camera focused on a YAK-50 performing a gear up landing?
Excuse me... ?
This is silly. You make an approach with the gear up in a 50, there is a loud buzz and before you can say WHAT THE F__K WAS THAT? You have 10 inches or more gone off each end of your prop.
Who cares if it came off 1/10th of an inch at a time? And I find that number to be variable on sink rate and engine RPM at the time, don't you think?
Mark Bitterlich
________________________________
From: http://us.mc511.mail.yahoo.com/mc/compose?to=owner-yak-list-server(at)matronics.com (owner-yak-list-server(at)matronics.com) on behalf of Paul Hamlin
Sent: Tue 10/19/2010 2:28 PM
To: http://us.mc511.mail.yahoo.com/mc/compose?to=yak-list(at)matronics.com (yak-list(at)matronics.com)
Subject: RE: Engine failure in Yak-50
He said, per strike
--- On Tue, 10/19/10, Bitterlich, Mark G CIV Det Cherry Point, MALS-14 64E <http://us.mc511.mail.yahoo.com/mc/compose?to=mark.bitterlich(at)navy.mil (mark.bitterlich(at)navy.mil)> wrote:
From: Bitterlich, Mark G CIV Det Cherry Point, MALS-14 64E <http://us.mc511.mail.yahoo.com/mc/compose?to=mark.bitterlich(at)navy.mil (mark.bitterlich(at)navy.mil)>
Subject: RE: Engine failure in Yak-50
To: http://us.mc511.mail.yahoo.com/mc/compose?to=yak-list(at)matronics.com (yak-list(at)matronics.com)
Date: Tuesday, October 19, 2010, 5:12 PM
--> Yak-List message posted by: "Bitterlich, Mark G CIV Det Cherry Point, MALS-14 64E" <http://us.mc511.mail.yahoo.com/mc/compose?to=mark.bitterlich(at)navy.mil (mark.bitterlich(at)navy.mil) <http://us.mc511.mail.yahoo.com/mc/compose?to=mark.bitterlich(at)navy.mil> >
Excuse me, but that is not accurate information when it comes to a YAK-50
Much more than a 1/10 of an inch gets shaved off on a YAK-50 that lands gear up. I think you might have misread the article (I did not read it myself), or he might have been talking about some other type of aircraft than a YAK-50.
A YAK-50 making a gear up landing will take about 10 or 12 INCHES off the prop (or more). I own one of these aircraft and there is no question about that.
Mark Bitterlich
________________________________
From: http://us.mc511.mail.yahoo.com/mc/compose?to=owner-yak-list-server(at)matronics.com (owner-yak-list-server(at)matronics.com) <http://us.mc511.mail.yahoo.com/mc/compose?to=owner-yak-list-server(at)matronics.com> on behalf of Eric Wobschall
Sent: Tue 10/19/2010 8:23 AM
To: http://us.mc511.mail.yahoo.com/mc/compose?to=yak-list(at)matronics.com (yak-list(at)matronics.com) <http://us.mc511.mail.yahoo.com/mc/compose?to=yak-list(at)matronics.com>
Subject: Re: Engine failure in Yak-50
There's a Carl Hayes article (on the M-14P.com website) that explains that for any damage at all to occur, a (torsional resistance) of 400 lb-ft (I think) must be encountered to cause damage. During a regular (gear-up) landing on pavement with the wood prop, only one-tenth of an inch of blade is shaved off per rotation, which gets nowhere near that force. On the other hand, if you hit something else more abruptly, the inertia of things on the accessory shafts will shear those shafts off or twist them out of sync. This is all paraphrased, so if you haven't read it, you should read Carl's article, which addresses all kinds of prop strikes.
On Oct 18, 2010, at 10:20 PM, Roger Kemp M.D. wrote:
Not sure but I think I heard that there is a design shear point in shaft. But, if that were so why would a prop strike not do the same.
So the answer is I do not know.
Doc
From: http://us.mc511.mail.yahoo.com/mc/compose?to=owner-yak-list-server(at)matronics.com (owner-yak-list-server(at)matronics.com) <http://us.mc511.mail.yahoo.com/mc/compose?to=owner-yak-list-server(at)matronics.com (owner-yak-list-server(at)matronics.com) <http://us.mc511.mail.yahoo.com/mc/compose?to=owner-yak-list-server(at)matronics.com> ] On Behalf Of Eric Wobschall
Sent: Monday, October 18, 2010 5:27 PM
To: http://us.mc511.mail.yahoo.com/mc/compose?to=yak-list(at)matronics.com (yak-list(at)matronics.com) <http://us.mc511.mail.yahoo.com/mc/compose?to=yak-list(at)matronics.com>
Subject: Re: Yak-List: Engine failure in Yak-50
No problem, Doc.
So what is it that caused it to shear? Is that a deliberate design to prevent the engine from twisting off it's mounts from prop momentum? Otherwise, you'd think there wouldn't be enough inertia to just break free like that.
On Oct 18, 2010, at 4:17 PM, Roger Kemp M.D. wrote:
Sorry Eric, I wrote my response before seeing that you had already seen Robs post.
Doc
From: http://us.mc511.mail.yahoo.com/mc/compose?to=owner-yak-list-server(at)matronics.com (owner-yak-list-server(at)matronics.com) <http://us.mc511.mail.yahoo.com/mc/compose?to=owner-yak-list-server(at)matronics.com (owner-yak-list-server(at)matronics.com) <http://us.mc511.mail.yahoo.com/mc/compose?to=owner-yak-list-server(at)matronics.com> ] On Behalf Of Eric Wobschall
Sent: Monday, October 18, 2010 1:47 PM
To: http://us.mc511.mail.yahoo.com/mc/compose?to=yak-list(at)matronics.com (yak-list(at)matronics.com) <http://us.mc511.mail.yahoo.com/mc/compose?to=yak-list(at)matronics.com>
Subject: Re: Engine failure in Yak-50
Engine seized with broken gearbox, too. Well, OK... so that's how, which surprises me. Having access to the failed engine certainly trumps speculation.
On Oct 18, 2010, at 11:47 AM, Richard Goode wrote:
For those interested in more details:
· As had been suggested, I am sure the oil pressure would have fallen as the pressure release valve became unscrewed.
· Andy says that he noticed the zero oil pressure pretty much at the same time as the prop (as one would expect) went into coarse pitch.
· The engine then actually kept going for 9/10 minutes without oil, which is quite impressive.
· Oil temperatures didn't go up simply because there was no oil and so nothing to measure! This of course was the reason for the engine failure - because the pressure release valve had not been wire-locked, it unscrewed and fell out.
· However it then totally seized and this is what broke the gearbox - hence the propeller continuing to windmill with a seized engine.
· The extent of the seizure was such that it is impossible to remove most of the cylinders!
· I would expect the CHT to have risen a bit, but only because a small part of it is oil-cooled, but the vast majority of cooling is through air, and of course he was at very low power settings in order to preserve the engine.
· In terms of gear-up of gear-down, I am sure gear-up is the safest way, but also, will cause far less damage to the aircraft.
Richard Goode Aerobatics
Rhodds Farm
Lyonshall
Herefordshire
HR5 3LW
United Kingdom
Tel: +44 (0) 1544 340120
Fax: +44 (0) 1544 340129
http://www.russianaeros.com/ <http://www.russianaeros.com/>
style="color: blue; text-decoration: underline; ">http://www.matronics.com/Navigator?Yak-List
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radiopicture
Joined: 23 Jun 2008
Posts: 263
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| Posted: Tue Oct 19, 2010 4:40 pm Post subject: Engine failure in Yak-50 |
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He my have been referring only to the Yak-52, and apparently, you
misread what is below. I said 1/10th or an inch PER ROTATION.
May very well not apply to the Yak-50.
On Oct 19, 2010, at 12:12 PM, Bitterlich, Mark G CIV Det Cherry Point,
MALS-14 64E wrote:
| Quote: |
Point, MALS-14 64E" <mark.bitterlich(at)navy.mil>
Excuse me, but that is not accurate information when it comes to a
YAK-50
Much more than a 1/10 of an inch gets shaved off on a YAK-50 that
lands gear up. I think you might have misread the article (I did
not read it myself), or he might have been talking about some other
type of aircraft than a YAK-50.
A YAK-50 making a gear up landing will take about 10 or 12 INCHES
off the prop (or more). I own one of these aircraft and there is
no question about that.
Mark Bitterlich
________________________________
From: owner-yak-list-server(at)matronics.com on behalf of Eric Wobschall
Sent: Tue 10/19/2010 8:23 AM
To: yak-list(at)matronics.com
Subject: Re: Engine failure in Yak-50
There's a Carl Hayes article (on the M-14P.com website) that
explains that for any damage at all to occur, a (torsional
resistance) of 400 lb-ft (I think) must be encountered to cause
damage. During a regular (gear-up) landing on pavement with the wood
prop, only one-tenth of an inch of blade is shaved off per rotation,
which gets nowhere near that force. On the other hand, if you hit
something else more abruptly, the inertia of things on the accessory
shafts will shear those shafts off or twist them out of sync. This
is all paraphrased, so if you haven't read it, you should read
Carl's article, which addresses all kinds of prop strikes.
On Oct 18, 2010, at 10:20 PM, Roger Kemp M.D. wrote:
Not sure but I think I heard that there is a design shear point in
shaft. But, if that were so why would a prop strike not do the same.
So the answer is I do not know.
Doc
From: owner-yak-list-server(at)matronics.com [mailto:owner-yak-list-server(at)matronics.com
] On Behalf Of Eric Wobschall
Sent: Monday, October 18, 2010 5:27 PM
To: yak-list(at)matronics.com
Subject: Re: Engine failure in Yak-50
No problem, Doc.
So what is it that caused it to shear? Is that a deliberate design
to prevent the engine from twisting off it's mounts from prop
momentum? Otherwise, you'd think there wouldn't be enough inertia to
just break free like that.
On Oct 18, 2010, at 4:17 PM, Roger Kemp M.D. wrote:
Sorry Eric, I wrote my response before seeing that you had already
seen Robs post.
Doc
From: owner-yak-list-server(at)matronics.com [mailto:owner-yak-list-server(at)matronics.com
] On Behalf Of Eric Wobschall
Sent: Monday, October 18, 2010 1:47 PM
To: yak-list(at)matronics.com
Subject: Re: Engine failure in Yak-50
Engine seized with broken gearbox, too. Well, OK... so that's how,
which surprises me. Having access to the failed engine certainly
trumps speculation.
On Oct 18, 2010, at 11:47 AM, Richard Goode wrote:
For those interested in more details:
· As had been suggested, I am sure the oil pressure would
have fallen as the pressure release valve became unscrewed.
· Andy says that he noticed the zero oil pressure pretty
much at the same time as the prop (as one would expect) went into
coarse pitch.
· The engine then actually kept going for 9/10 minutes
without oil, which is quite impressive.
· Oil temperatures didn't go up simply because there was no
oil and so nothing to measure! This of course was the reason for
the engine failure - because the pressure release valve had not been
wire-locked, it unscrewed and fell out.
· However it then totally seized and this is what broke the
gearbox - hence the propeller continuing to windmill with a seized
engine.
· The extent of the seizure was such that it is impossible
to remove most of the cylinders!
· I would expect the CHT to have risen a bit, but only
because a small part of it is oil-cooled, but the vast majority of
cooling is through air, and of course he was at very low power
settings in order to preserve the engine.
· In terms of gear-up of gear-down, I am sure gear-up is
the safest way, but also, will cause far less damage to the aircraft.
Richard Goode Aerobatics
Rhodds Farm
Lyonshall
Herefordshire
HR5 3LW
United Kingdom
Tel: +44 (0) 1544 340120
Fax: +44 (0) 1544 340129
www.russianaeros.com <http://www.russianaeros.com/>
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radiopicture
Joined: 23 Jun 2008
Posts: 263
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| Posted: Tue Oct 19, 2010 4:41 pm Post subject: Engine failure in Yak-50 |
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PEOPLE!! READ BEFORE YOU POP OFF!! Less that 1/10th PER ROTATION!!!
On Oct 19, 2010, at 12:28 PM, pilko2 wrote:
[quote]
And I'm looking across my office at a selection of unintentionally
shortened
prop blades from that very same Yak 50 and concur at least 10 inches
of "Oh
bugger" is involved !
kp
--
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