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Post by MarkGregor on Oct 8, 2017 4:25:03 GMT
The Gearbox on the 914, 912ULS and 912iS are all different. We have only seen gearbox problems w the 912iS.
Mark
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timb
Full Member
Posts: 117
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Post by timb on Nov 27, 2017 18:44:37 GMT
UPDATE ! , only 44 hours on my completely rebuilt gearbox and I'm experiencing a troublesome vibration mostly in the 5400+ rpm range. We just returned home to Florida from a trip to New Mexico and back, about 9 hours flight time into the trip we started feeling the vibration that comes and goes with no set interval, it will vibrate for a minute or several then smooth for awhile and repeat. The vibration is very noticeable, I not only hear it I can feel it. I've had this gearbox worked on five times within the first 500+ hours since new. This 912is engine has run nearly flawlessly for the 600 hours that are now on it, even when the gearbox chewed up the friction washer and partially blocked oil flow the engine ran fine with only 20 psi oil pressure. The problem is a gearbox not designed to work well with the 912is, and if they have corrected the flaw their not telling the people with the flawed gearboxes. California Power Systems, who rebuilt the gearbox for me this last time filed a claim with Rotax to reimburse me for the cost, but two months now and NOTHING. If others have had gearbox problems with their 912is please post, I have read on other forums that I'm not the only one. Maybe the problem is big enough for a class action??  |
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Post by stroudj on Nov 27, 2017 19:26:36 GMT
Tim,
I suggest that you check your spinner backing plate for cracks and the pitch on each blade. It only takes a 2 tenths of a degree difference to cause a vibration like you described.
Thanks,
Jim
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Post by Flocker on Jul 20, 2018 14:47:41 GMT
Looks like Rotax came out with a fix for the 912iS Gearbox vibration issue. The IPC has been updated and there is a new Gearbox cover assembly with a new oil spray nozzle assembly.
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Post by jetcat3 on Jul 20, 2018 19:40:15 GMT
That’s great to hear Jim! It’s a sweet little engine. The more and more I’ve flown behind and learned about the 912 iS Sport I’ve become very impressed. That’s a smooth running jewel! Crazy throttle response too.
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Post by Flocker on Jul 21, 2018 12:27:49 GMT
The IPC has been updated and there is a new Gearbox cover assembly with a new oil spray nozzle assembly. Part #19 and #29 are the new parts:  |
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Post by slingpilot on Aug 12, 2018 19:30:33 GMT
The iS is a great engine, however, even with many in service they continue to have gearbox issues. It is a know fact. When ordering my S-LSA, I really wanted the iS engine, but I went with the ULS. I know Rotax will fix it eventually.
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Post by geobuff on Aug 31, 2018 2:50:01 GMT
Just spoke with Joe at Lockwood a few days ago. I asked him about the new gearbox pictured above. He said yes, sounds great, but Lockwood has yet to see their first one. As of last week they have not been delivered to the service centers.
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Post by slingpilot on Sept 2, 2018 13:53:17 GMT
I ordered my Sling 2 with the ULS rather than the iS, for the issues outlined in this thread regarding the gearbox. In fact, I applaude TAF for steering me in the direction of the ULS, as I had wanted the iS. It appears that premature vibration problems and maintenance issues have plagued the iS from its inception. Glad to hear ROTAX has finally found the solution to the problem. Meantime, I’m happy with my ULS powered Sling 2 and hopefully will not have to endure a premature overhaul of my gearbox.
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Post by Flocker on Sept 12, 2018 19:53:36 GMT
Add me to the list of 912iS owners with the gearbox issue. After experiencing a high frequency vibration in flight I decided to have my gearbox pulled. Turns out it was the gearbox. Pitting on the dog hub specifically. Lockwood confirmed there is a new part in the pipeline, but it has not shipped to the service centers as of yet. Poor lubrication seems to be the culprit hence the new oil spray nozzle assembly mentioned above. PS - I now know far more about Tribology than I ever cared to know.  |
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Post by Tony on Sept 13, 2018 16:45:22 GMT
Looking at the gearbox assemblies in the IPCs there doesn't seem to be much difference between the 912/914 and the 912i. Does anyone know why this issue is so much more prevalent in the 912iS?
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Post by Flocker on Sept 13, 2018 17:00:05 GMT
From one of the experts on rotax-owner.com:
"Part of the difference is the UL and ULS have a 30 degree dog hub set and the 912iS has a zero dog gear setup. The 912iS needs more oil on top of the gear setup in the box and they are working on it."
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Post by Tony on Sept 13, 2018 17:22:01 GMT
That makes sense. The 912iS doesn't make that nice little clunk noise when you burp the engine then.  |
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timb
Full Member
Posts: 117
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Post by timb on Apr 19, 2019 2:41:30 GMT
An update on my gearbox vibration issue - as of last November I have a new 912is engine with the new gearbox with oilers. The engine runs beautiful, and feels the same as the previous engine when it ran smoothly.
A more than fair resolution was worked out with Rotax for the gearbox issue that plagued me for years. I believe it's important to document problems from the start when you are under warranty and continue if it's an ongoing problem even after your warranty expires, it helped me.
Having a Rotax service center documenting my planes maintenance was key.
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Post by buzz on Apr 19, 2019 3:11:00 GMT
Nice!
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