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  #11  
Old 09-10-2014, 06:03 AM
Mike H Mike H is offline
 
Join Date: May 2014
Location: Savannah
Posts: 806
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Check out the way some OEMs install the 912.

http://www.flypipistrel.com/manuals/...e-Airframe.pdf

http://www.pipistrelbuilders.com/rot...fications.html

When you perform the slipper clutch torque check procedure you will subject the prop flange, gearbox, crankcase etc. to WAY MORE force than simply storing or performing maintenance on the engine while it is bolted to a crankshaft type engine stand.
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  #12  
Old 09-10-2014, 07:01 AM
roger lee roger lee is offline
 
Join Date: Sep 2013
Location: Tucson, AZ
Posts: 322
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Quote from above:
"I'm not sure how or if the Rotax gearbox changes that equation, though."

The ones done in A&P school or other places were most likely direct drive engines like Cont. & Lycoming and they didn't have a gearbox.

Here is the comment from Rotax.

"Both are bad news for the engine. Let is remember that this is not a
direct drive, the weight and all the forces are not in direct line with
the crankshaft, it is offset to because of the gearbox.


This type of mounting is common on direct drive engines and should be
avoided on geared engines for this reason.
The worst is the one were the
engine is flat and all the mechanical leverage on the prop flange could
perhaps cause a real problem with the bending or fractures of the inner
bearing retaining bolts."


Bottom line don't do it and don't treat a Rotax like a Cont. or Lycoming. Number one mistake by A&P's working on a Rotax. Fixing A&P work on a Rotax is approximately 30% of my business because they either treat them like a Cont. or Lycoming or have no idea about LSA regs.
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Last edited by roger lee : 09-10-2014 at 07:04 AM.
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  #13  
Old 09-10-2014, 07:34 AM
Mike H Mike H is offline
 
Join Date: May 2014
Location: Savannah
Posts: 806
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Quote:
Originally Posted by roger lee View Post
Here is the comment from Rotax.

"Both are bad news for the engine. Let is remember that this is not a
direct drive, the weight and all the forces are not in direct line with
the crankshaft, it is offset to because of the gearbox.


This type of mounting is common on direct drive engines and should be
avoided on geared engines for this reason.
The worst is the one were the
engine is flat and all the mechanical leverage on the prop flange could
perhaps cause a real problem with the bending or fractures of the inner
bearing retaining bolts."


Bottom line don't do it and don't treat a Rotax like a Cont. or Lycoming. Number one mistake by A&P's working on a Rotax. Fixing A&P work on a Rotax is approximately 30% of my business because they either treat them like a Cont. or Lycoming or have no idea about LSA regs.
Who "from Rotax" gave you this information? was it engineering, tech support....? I would like to see some data on this.
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  #14  
Old 09-10-2014, 07:40 AM
hthaman hthaman is offline
 
Join Date: Jan 2014
Location: IA
Posts: 56
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Quote:
Originally Posted by roger lee View Post
Quote from above:
"

[/u] The worst is the one were the
engine is flat and all the mechanical leverage on the prop flange could
perhaps cause a real problem with the bending or fractures of the inner
bearing retaining bolts."
thanks for all the efforts you have made on this post, so from Rotax point of view some components on the gear box I could ask my local Rotax tech to check on the "gearbox" ??
I am glad the engine was on its nose for "few hrs" only instead of many days.
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  #15  
Old 09-10-2014, 07:54 AM
roger lee roger lee is offline
 
Join Date: Sep 2013
Location: Tucson, AZ
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I can't post my source, but will say it comes from someone high up and has been with the company for close to 30 years. I doubt there is any real written researched and tested data because no one should have done it in the first place and until the last day or two I have never seen or heard of this on a Rotax and neither has two the master Rotax distributors for all of Canada or the America's.

If people have never done something on a Rotax engine before I believe they should pick up a phone and ask. That would save tens of thousands of dollars in un-necessary owner and mechanic caused repairs. There is no shame in doing it right the first time or learning something new. I get 6-10 calls a day for issues and when I get a head scratchier I pick up the phone and call someone in the know up the food chain.
When I'm not sure I always grab the phone. It's far better safe than sorry and not just because of the money, but the liability as a mechanic and even the owner if you hurt a passenger or someone on the ground. Remember the FAA says the owner is ultimately responsible for the aircraft.
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Last edited by roger lee : 09-10-2014 at 08:00 AM.
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  #16  
Old 09-10-2014, 08:05 AM
Mike H Mike H is offline
 
Join Date: May 2014
Location: Savannah
Posts: 806
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Still does not pass the smell check for me. The engine weighs less than 140 lbs dry. At take off power the prop flange, PSRU and engine case are subjected to more than this amount of force.
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  #17  
Old 09-10-2014, 11:55 AM
sandpiper sandpiper is offline
 
Join Date: Nov 2009
Location: Independence, OR
Posts: 316
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Why risk it. Sure, the engineer in me says more load is placed on it when mounted on a plane and in operation. But, I designed highways and airports, not engines.

Roger doesn't want to disclose his source, I am guessing, because doing so would probably mean loss of that source in the future. So, if you want an "official" answer, write Rotax.
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  #18  
Old 09-10-2014, 12:01 PM
DHeal DHeal is offline
 
Join Date: Sep 2006
Location: Windsor, California
Posts: 924
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That cantilever apparatus gives me the willies! There is no need to do other than follow Van's plans when installing the ROTAX 912 in the RV-12 -- the recommended engine installation procedures work fine.
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  #19  
Old 09-10-2014, 01:17 PM
E. D. Eliot E. D. Eliot is offline
 
Join Date: Dec 2005
Location: San Pedro
Posts: 1,013
Default Why not?

One of the things that I have learned as a product of 'being older' is that if I look at something or think about something that gives me question as to right or wrong, i don't do it.

So, whomever wants to be the first to test this manner of mounting a Rotax engine, even if temporarily, go ahead - heck, you're only risking maybe 15-25K to do the experiment. Too many unknowns as enumerated in previous posts. I won't do it because it looks wrong and I can't afford the price of the experiment. Good luck!
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  #20  
Old 09-10-2014, 01:58 PM
Dave12 Dave12 is offline
 
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Location: Elkton, Md.
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Bottom Line, it's your engine. Do whatever you want. Roger offers a very sensible opinion, but you don't have to share it. If you simply unbolt the engine from the crate, it will sit on your bench and is very easy to work on in that position. It's your money!
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