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Thread: Airmaster install/conversion on a 914UL2...

  1. #1

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    Question Airmaster install/conversion on a 914UL2...

    Somehow I got involved in the rebuild of a Kitfox that had an accident. But it has been a fun project... The prop was destroyed, among other things, and the owner wants an Airmaster installed.

    This engine is a Rotax 914UL Series 2 and had the optional prop governor.

    Since the hydraulic governor will be removed a few changes will need to be made to the engine, particularly at the back of the gearbox housing where the governor used to be.

    Has anyone out there done this?

    I've already talked to Martin at Airmaster and asked if there was a conversion kit and he was unaware of one.

  2. #2
    Senior Member Esser's Avatar
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    Default Re: Airmaster install/conversion on a 914UL2...

    Iím not understanding your question. I have a 914 with an AirMaster. Not familiar with your CS setup now but Iím assuming you can just block it off and use the AirMaster electric bracket.
    ------------------
    Josh Esser
    Flying SS7
    Rotax 914iS
    AirMaster Prop

    Edmonton, AB, CWL3

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    Default Re: Airmaster install/conversion on a 914UL2...

    Quote Originally Posted by Esser View Post
    Iím not understanding your question. I have a 914 with an AirMaster. Not familiar with your CS setup now but Iím assuming you can just block it off and use the AirMaster electric bracket.
    Thanks for the reply. The devil is always in the details or so it seems. This particular 914UL is listed by serial number as a Version 2. (The different versions 2,3,4 have to do with how prop shafts and gearboxes are configured. (At least that is what I'm getting out of the Illustrated Parts Catalog. Don't quote me on that I could be totally off about this and/or there could be way more than I understand to it.) Anyway, this engine has the optional hydraulic prop governor for a constant speed propeller. After the crash, it was decided to change all of this to an electrically controlled Airmaster. The Hydr. governor and it's associated drive gear come off and that leaves holes in the back of the gearbox that need to be covered. Obviously, there needs to be a plate bolted in place. Another concern is the rear bearing supporting the prop shaft. There were ports in the Hydr. governor mounting plate that appeared to provide oil to lubricate that bearing. If we fashion a simple cover plate to block off the back of the gearbox will this very important bearing suffer from oil starvation? There are a few other differences too that need to be addressed in this conversion, but I've already gone on long enough.

    My question is: Has anyone converted a 914 with a hydraulic prop governor to an Airmaster with the electric control? I'm trying not to reinvent the wheel here and am concerned about the reliability of the engine.

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    Lightbulb Re: Airmaster install/conversion on a 914UL2...

    New information, from a closer look at the Rotax IPC. I keep referring to this 914UL as a Version 2 and that is what the S/N shows it to be. But in reality, it has had the Version 2 to 3 Prop Shaft Config. retro kit installed, Rotax P/N 881702 to enable the engine to drive either a constant speed prop governor or a vacuum pump. A Version 2 install looks like this... Aft view of 912 gearbox.jpg Maybe those parts would help solve my problem. (Note the oil leakage. Looks like that seal might need replacement.)

    Another part of this puzzle is the oil feed line from the pump to the governor mounting plate. If that line is removed the banjo feed line bolt at the oil pump is too long. The simple solution would seem to just use a shorter feed bolt, but the oil feed line that must remain, for the turbo bearings, is a hard part and I would hate to crack or kink the line trying to make its effective length shorter. Guess a bushing to replace the banjo fitting and use the same feed bolt might work. (FYI the missing crush washers are on the workbench.)

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    Senior Member Esser's Avatar
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    Default Re: Airmaster install/conversion on a 914UL2...

    I would r commend calling Rotech in Vernon. They probably know what to do.
    ------------------
    Josh Esser
    Flying SS7
    Rotax 914iS
    AirMaster Prop

    Edmonton, AB, CWL3

  6. #6
    Senior Member aviator79's Avatar
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    Default Re: Airmaster install/conversion on a 914UL2...

    Talk to some experts, but I think you're looking at a lot more effort than it's worth. This will not be a bolt-on project.

    Edit - I looked over my engine overhaul pictures, and I think it might not be quite as difficult as I thought. I think you may need a different drive shaft though. I'm not seeing how the brass governor drive you have is compatible with the hollow driveshaft that's compatible with the Airmaster. Maybe the IPC makes this clearer.

    Edit 2 - I looked at the IPC. You may not need much more than that propeller shaft, and it's about $900. Not cheap, but also not crazy talk compared to the cost of the Airmaster Prop. I am far from an expert, so definitely consult CPS, LEAF, or Rotech.
    Last edited by aviator79; 02-05-2019 at 03:10 PM.
    --Brian
    Flying - S7SS

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    Question Re: Airmaster install/conversion on a 914UL2...

    This has become, apparently, uncharted territory. I still can't believe the upgrade hasn't been done by someone before. Airmaster has not done this conversion nither has Kitfox. No replies from Rotax-Owners.com, yet. My next step is to talk to some of the Rotax shops like has been suggested, Lockwood, Rotech, or CPS. The IPC shows a cover plate that apparently blocks off the governor plate and a bushing for the banjo oil feed bolt at the oil pump. Everyone is correct in saying the prop shaft for these different versions is different. This engine has had a version 3 conversion added, also noted in the IPC but not illustrated so we don't know what the kit contains. The prop shaft is hollow allowing oil to feed the hydr. prop hub, which is no longer used, and the rear prop shaft support bearing is different. More research is needed. Thanks for the suggestions so far.

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