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  #31  
Old 10-22-2017, 09:58 AM
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rv6ejguy rv6ejguy is offline
 
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Quote:
Originally Posted by DanH View Post
If there is an "automotive method", it would be that the auto industry actually understands torsional vibration, and incorporates vibratory analysis into the design process. It is good application of fundamentals, not magic parts.
Absolutely and as Terrye said, few in the aircraft auto conversion/ PSRU world either understand or test their packages for TV issues. Powersport and EPI come to mind who do test.

Tracy at RWS did design for this and Neil Hintz at AutoFlight as well although I'm not aware the latter two did any instrumented testing on specific engine, drive/ prop combinations. These two do have tens of thousands of hours collectively on many drives though without many failures which would seem to confirm their TV solutions work.
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  #32  
Old 10-23-2017, 08:21 AM
Tomcat RV4 Tomcat RV4 is offline
 
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I am curious if Ross would agree,but my personal experience w J25 is std stock flywheel and rubber coupling ,makes for smooth running combo ! Sometimes our obsession w
Weight is a detriment ! Tom
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  #33  
Old 10-23-2017, 08:42 AM
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David-aviator David-aviator is offline
 
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Quote:
Originally Posted by Tomcat RV4 View Post
I am curious if Ross would agree,but my personal experience w J25 is std stock flywheel and rubber coupling ,makes for smooth running combo ! Sometimes our obsession w
Weight is a detriment ! Tom
I was involved in an effort to get MT to come to US and do vibration analysis of MT prop and H6 engine.

The results were very good which gave confidence to continue the effort.
So far as engine, psru and prop were concerned, it was a comfort.

But that in flight testing probably is different than what is being discussed here. PSRU failure happened down the road and must have been caused by bearing load factors, not vibration.
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  #34  
Old 10-23-2017, 08:47 AM
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Quote:
Originally Posted by Tomcat RV4 View Post
I am curious if Ross would agree,but my personal experience w J25 is std stock flywheel and rubber coupling ,makes for smooth running combo ! Sometimes our obsession w
Weight is a detriment ! Tom
I think you're flying with an SPG-3 or 4 gearbox correct?
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Ross Farnham, Calgary, Alberta
Turbo Subaru EJ22, Marcotte M-300, IVO, RV6A C-GVZX flying from CYBW- 416.6 hrs. on the Hobbs,
RV10 95% built- Sold 2016
http://www.sdsefi.com/aircraft.html
http://sdsefi.com/cpi.htm


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  #35  
Old 10-23-2017, 08:52 AM
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Quote:
Originally Posted by David-aviator View Post
I was involved in an effort to get MT to come to US and do vibration analysis of MT prop and H6 engine.

The results were very good which gave confidence to continue the effort.
So far as engine, psru and prop were concerned, it was a comfort.

But that in flight testing probably is different than what is being discussed here. PSRU failure happened down the road and must have been caused by bearing load factors, not vibration.
It seems on the Egg Gen 3 boxes there were 3 somewhat common failures- drive splines, broken gear welds and bearings falling apart. There were also some TV issues on startup for some people which were addressed by adding a bunch of ign timing during cranking. Counter-intuitively, this seemed to fix the dreadful sledgehammer blows experienced. Hopefully the revised box design by Mike addresses all these issues.
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Ross Farnham, Calgary, Alberta
Turbo Subaru EJ22, Marcotte M-300, IVO, RV6A C-GVZX flying from CYBW- 416.6 hrs. on the Hobbs,
RV10 95% built- Sold 2016
http://www.sdsefi.com/aircraft.html
http://sdsefi.com/cpi.htm


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  #36  
Old 10-23-2017, 12:09 PM
simpkinsona simpkinsona is offline
 
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Default Egg gearbox

The spline shaft failures were all on aircraft with solid flywheels. The adapter bolted to the flywheel would eventually strip out due to fretting from the piston impulses. The dual mass flywheel seems to have eliminated that problem although frequent inspections are still a good idea.

The weld issue is a continuing problem that seems to be related to the bearing failures. It's always the same bearing and it's attached to the welded output shaft. I have one gearbox that has more vibrations and develops leaks at the front seal. It had some roughness in that bearing when I inspected it before replacing that bearing. My other gearbox has 850 hours on it and runs smoothly with no issues. I haven't taken apart the bad gearbox yet but my suspicion is that the welded shaft is warped slightly from the welding operation and that causes the vibration and bearing failures.

I think if you have a good smooth egg gearbox it will last indefinitely. I'm planning to try find a better output shaft or make my own for my spare gearbox.

-Andy
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  #37  
Old 10-23-2017, 05:12 PM
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Yet I know of some solid flywheel Eggs with 500+ hours and no spline failures (so far) so I don't think we can be sure that is causal. Without a TV study, we really don't know the differences in amplitude at flight range frequencies to point a finger.

I thought there was a spline failure on a DM equipped engine but I could have the owner mixed up with another guy. I'll poll Subenews and see if anyone reports a spline failure on a DM setup.
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Ross Farnham, Calgary, Alberta
Turbo Subaru EJ22, Marcotte M-300, IVO, RV6A C-GVZX flying from CYBW- 416.6 hrs. on the Hobbs,
RV10 95% built- Sold 2016
http://www.sdsefi.com/aircraft.html
http://sdsefi.com/cpi.htm



Last edited by rv6ejguy : 10-23-2017 at 07:30 PM.
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  #38  
Old 10-23-2017, 05:23 PM
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This just in from Flysoob:

"The Ghost Run Air Race took place yesterday. Our Glasair/Subaru dominated all other piston aircraft. We came in second behind Mike Patey and his turbine powered Extreme Lancair Legacy.

Our Subaru EG33 ran its fastest race ever. The average speed over a 155 nautical mile course was 256.91 MPH.

Man, I love this Subaru!

Russell Sherwood"

This is Russell's 6th class win this year in SARL (has won every race entered this year). People still wanna believe Subarus can't work well in aircraft?
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Ross Farnham, Calgary, Alberta
Turbo Subaru EJ22, Marcotte M-300, IVO, RV6A C-GVZX flying from CYBW- 416.6 hrs. on the Hobbs,
RV10 95% built- Sold 2016
http://www.sdsefi.com/aircraft.html
http://sdsefi.com/cpi.htm



Last edited by rv6ejguy : 10-23-2017 at 07:32 PM.
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  #39  
Old 11-12-2017, 02:19 PM
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rv6ejguy rv6ejguy is offline
 
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Russell just set a new SARL class record on Nov. 11- 261.60 mph running the entire race at 5250 rpm.

Below are the season results of his 2017 races

Texoma Air Race - 145 mile closed circuit - Average speed 250.94 MPH

BCAF Air Race - 159 mile closed circuit - Average speed 252.95 MPH

Hardin Air Race - 135 mile closed circuit - Average speed 251.92 MPH

Big Muddy Air Race - 137 mile closed circuit - Average speed 254.77 MPH

Indy Air Race - 133 mile closed circuit - Average speed 256.66 MPH

Ghost Run Air Race - 155 mile closed circuit - Average speed 256.91 MPH

Rocket Air Race - 159 mile closed circuit - Average speed 261.60 MPH

The Lycoming guys will have some work ahead to catch him next year.
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Ross Farnham, Calgary, Alberta
Turbo Subaru EJ22, Marcotte M-300, IVO, RV6A C-GVZX flying from CYBW- 416.6 hrs. on the Hobbs,
RV10 95% built- Sold 2016
http://www.sdsefi.com/aircraft.html
http://sdsefi.com/cpi.htm



Last edited by rv6ejguy : 11-12-2017 at 05:40 PM.
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  #40  
Old 11-13-2017, 11:28 AM
Tomcat RV4 Tomcat RV4 is offline
 
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Ross, yes I had SPG- 4. I don't claim to be an engineer, but was very impressed with the use of a BMW/Mercedes drive shaft type rubber coupling to act as shock/torque absorber. Plus the 3 blade cool prop (which fits rotax hub) very light. Airtrikes indicated it was good up to 160HP. I think they may have raised HP.
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