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Rotax on engine stand question

hthaman

Active Member
Can someone advice if thats "ok" or not to keep the new engine for few days on a stand like in the picture please.

 
I don't think in 15 years I have ever seen or heard of this being done.

Personally I don't think that is the best solution. The engine has more than enough mass to tweak that prop flange and I'm not sure what it may do to the shaft oil seal. I see you still have the metal crate plates on the bottom. Why not just set it on those or two blocks of parallel wood?

The prop shaft and new bearings and seals will cost about $750 just for the parts not including labor. There is some oil still left in the engine, not much, but no sure where it's going to go.
 
I would like to post this picture on the Rotax website and get some comments if you don't have any objections?
 
found another thread below, 07 built and guy said stand like in this pic is in the rotax manual.

http://www.pipistrelbuilders.com/rotax_engine_modifications.html


I spoke with rotax tech at leading edge air foils, he said should be fine but rotax tech at lockwood aviation said the crank shaft should be checked for bent.





is there any testing can be done during the engine run at final that can make sure all is well inside it ??
 
I sent it to US Rotax main distributor. I'm awaiting a comment.
I just wouldn't treat my $18K engine this way. Just tweak the shaft or prop flange ever so slightly and it's vibration city and a new shaft, oil seal and bearing is in your future.

I think if Rotax thought this was okay some where in a class, the crate or the factory they would do it, but they don't.
 
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I'm not sure why anyone would attempt hanging or standing the engine from the prop flange. Seems way to risky to bend something. We left the shipping rails on the bottom and did everything required on a flat workbench.
 
Standing on the flange like that is how traditional engines like Lycomings are worked on. It was certainly my experience at A&P school.

They're obviously subjected to large loads in excess of their own weight fore and aft in standard and pusher configurations while flying, so it seems logical that sitting on a stand in the same orientation would be okay.

I'm not sure how or if the Rotax gearbox changes that equation, though.

http://www.alaskanaircraftengines.com/engine-removal.html
http://jeffsplanes.com/Cub/engine.jpg
http://jeffsplanes.com/Engines/IMG_7093.JPG
http://rilinterface.com/Traveler/Images/Engine/PIC-0049.jpg
http://www.berkut13.com/engine04.jpg
 
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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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.
 
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.
 
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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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.
 
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.
 
That cantilever apparatus gives me the willies! :eek: 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.
 
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!
 
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!
 
The engine hanging sideways from the prop flange stands a good chance of cracking the prop shaft bearing and or ruining the oil seal. The first engine upside down should only need a dial caliper put up against the prop flange before first start and just make sure it is still true. I talked to the owner today and I think he should be fine.
 
I can't speak for the builder assistance center this aircraft is currently located at, but I can tell you I have rebuilt an RV7A and and RV10 with their assistance, and am close to completing an old RV6A QB kit. I have rented space on an off for more than a decade.

My experience has been positive, the advice constructive and the results outstanding. They have saved me time and money by knowing shortcuts, having specialized tools, and the benefit of having built numerous award winning RVs.

I actually helped the owner set his Rotax on the stand. The shop was being helpful in providing a stand to him so he didn't have to set his engine on a plywood shipping crate in the middle of the hangar floor until a better solution was found. When the owner became nervous and asked for assistance in taking the engine back off the stand, I crawled out from under the dash of my own project and helped him lift it back off. I even suggested contacting the manufacturer if he had questions since this is the first 912 to be in the shop that I can recall.

A few of the exchanges in this thread may have appeared to suggest that the builder assistance center recommended using the engine stand. The exchange was more helpful in nature. In fact I said "It's too bad we don't have an engine stand so his engine doesn't sit on the lid of the shipping box in the middle of the floor." At which point the assistance center said they had one and I helped as a fellow builder lift it from the shipping crate. Nobody claimed to be a Rotax expert.

I am certain the engine is just fine. It was not mishandled in any way. The aerodynamic loading in flight will far exceed two hours on the stand. But as others have stated, it is his engine and project and the decision on what to do or not to do is his.

I personally look forward to the owner of this well-built project getting the FWF done and enjoying the RV grin like the rest of us do.
 
FWIW, if I was in your situation I would mount the engine, mount the prop and check the blade tracking. If it tracks properly nothing was bent.
 
So long as you check the flange for trueness and it doesn't leak oil around the seal it should be good to go.
Blade tracking may not be accurate enough. I would put a dial caliper up against the inside edge of the flange and turn the engine with one plug from each cylinder out. The out of true spec for the prop flange is the same for a prop strike and can be found in the heavy maint. manual.
 
Roger,

The dial check is a good idea. I suggested blade tracking because most guys don't have a dial indicator rig or experience in using it. The length of the blade makes even a small deviation from true obvious and doesn't require any special equipment.

Rich
 
Pipistrel is a large international aircraft company that manufactures several aircraft models that use the Rotax 912 series engine. They advertise 15 years experience consulting, maintaining, repair and overhauling of Rotax engines with trained mechanics.

On some models they make modifications to the engine and they do it at their factory using engine stands that bolt to the Rotax 912 prop flange and hold the engine in a horizontal position, see picture and text below.

"At Pipistrel we fix the engine to a stand, similar to the one in the photo below, this makes modifying and moving the engine around the workshop much easier. In a nutshell, this manual covers the following procedures: modifying the water pump, adding the oil thermostat, mounting the cooling plenum, mounting the exhaust system and mounting the oil coolers."

Rotax_zpsed6d20a7.png


Additionally, Pipistrel home builders have constructed similar stands out of plywood that suspend the engine horizontally by the prop flange. One such picture was posted earlier in this thread.

I?m not an A&P and I possess minimal knowledge regarding aircraft engines but it occurs to me that if the engine can be supported horizontally by its prop flange, setting the engine on its nose (prop flange) should NOT cause damage.

There have been several alarming comments made on this thread causing the owner of this engine great concern. I guess we all have opinions but when you tell an inexperienced builder that he may have caused serious damage to his brand new expensive engine because he set it on its nose for a couple hours and that he now needs to have it inspected for bent components, cracked bearing, broken seals ? well I?m just disappointed.

That?s my two cents regarding this issue.
 
I dunno - I wouldn't do it.

But then again I grew up in the world that if the owner of the flight school caught you moving an airplane by pushing or pulling on the prop, he would get really really pissed.

Nice thing about the Rotax is that if you treat it right, you might be the person breaking that 6000+ hr TBO record.
 
Joe,

I think most folks on this site are pretty conservative, and that's a good thing. Don't be too hard on 'em! ;)

Rich
 
Think of it this way. Hold 5 gals. of water up off the floor , but with your arm hanging straight down. No problem. The arm was designed to support heavier weight that way. Now hold that same 5 gals out at arms length. Don't let the elbow or wrist bend or the shoulder sag. Same water weight, but different use of the appendage which really wasn't designed to hold heavier weights like that. If you tear the rotator cuff (the prop flange) then you'll know that the flange on the plane has more weight suspended outward that it wasn't designed to carry in that type of side load.



Pipistrel has been having a few of their own issues lately with the 912is. I have been called by several owners.
If Rotax saw them suspend and engine like that they would just shake their head.
Remember this has a gearbox and is offset and then you dangle 125+ lbs out there by the flange as it puts all that side load in one spot on the oil seal and bearing. By the way the bearing is not all metal. Next time someone pulls a gearbox apart take a minute and look at the bearing down inside.There is plastic there for them to break and crack. This type of engine mount is an old hold over from the Cont. & Lycoming days. This isn't the same engine and people are supposed to be up on their game a little better.
Just because you get away with something doesn't make it right and you won't get tagged.
Criminals and tax dodgers do things all the time that are wrong and get away with it to, until eventually their day comes.

MFG's don't always do the right thing either. I have called 4 different MFG's to change their practices. All most need to do is read the manuals and all MFG's should be attending Rotax classes up through Heavy Maint.
I remember when a couple of MFG's were setting the prop pitch too course at 5200 WOT in flat and level flight. The crankcases before June 2006 would crack from the stress up on top. Now you know why those engines can't go to the 2000 hr. TBO. The crankcase was changed after that.

I would re-iterate that if Rotax thought this was acceptable method some where they would say so and they would have responded to me with that's not a good idea email. I have talked to two master distributors and both of them said to avoid this too. Lots of top level people saying do not do this verses 1-2 saying go for it. Must be a concern for some reason especially since these people have 30 years with Rotax. If this is a good idea why doesn't Rotax use it at their plant in Austria? All this should make you set back and think.


Last thought. If someone thinks this is okay then they wouldn't mind letting me pull their prop off, hang 125 lbs of weight cantilevered on the flange and then work all around pushing, banging and twisting that weight while I work on their engine. If you wouldn't allow someone to do that to your plane then why not?
Another thought:
You think while Pipistrel works on that engine they aren't generating more forces than just that 125 lb cantilevered weight as they push on hoses and work on that engine. Your 125 lb. engine all of a sudden developed more torque on the flange as the engine gets worked on.

I pull lots of engines for different things and I just suspend the engine from a solid mid engine point and I can get to the entire engine without stressing any parts.
 
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I hope no one here thinks anyone is jumping on them or being hard. Sometimes for me it's just stepping off the path you are on and taking an minute to look a situation from a different view. 28 years of emergency management has taught me to always step back and take a 360 degree plus top and bottom look because if we don't we miss things and make mistakes. Then we can't use the right correct measures and we waist the resources on the scene that is usually in short supply.
 
Maybe it's just me, but saying that "Criminals and tax dodgers do things all the time" doesn't mix with "I hope no one here thinks anyone is jumping on them or being hard."
 
"Maybe it's just me, but saying that "Criminals and tax dodgers do things all the time" doesn't mix with "I hope no one here thinks anyone is jumping on them or being hard."

Criminals and tax dodgers never think anything will happen to them.

and

"Joe,

I think most folks on this site are pretty conservative, and that's a good thing. Don't be too hard on 'em! "

Two different post with different thoughts in each.
 
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.
Remind us of who the two master Rotax distributors for Canada and the Americas are, please.
I assume one is Rotech, in B.C., CA, but on their web site they claim they are THE (one) distributor for North and South America so I'm stumped on the second distributor referenced. And, of course, if my understanding on Rotech is wrong correct me on that.
http://www.rotech.ca/overhaul.htm
 
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