BMW ENGINE AND GEARBOX IN A FLEXWING

Published by: DEMETRI NEOPHYTOU on 1st Jan 2015 | View all blogs by DEMETRI NEOPHYTOU
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Comments

10 Comments

  • DEMETRI NEOPHYTOU
    by DEMETRI NEOPHYTOU 3 years ago
    Hello friends.
    I will need some help here.
    A friend has installed a BMW engine to his flexwing with the gearbox pictured.
    Does anyone knows if this gearbox makes loud noise like metals banging in low RPM???????
    WHEN THE ENGINE IS RUNNING BELOW 2000RPM theres a loud noise coming out of it,,,,over 2000 RPM the noise stops.
    I said to my friend that my ROTAX 503 makes a similar loud noise ( like banging metals) when is running below 2000 RPM but when i rev up the noise stops.
    So here comes the question,,,,,,,does this gearbox works as the ROTAX B TYPE 2.58 : 1 ?????????
    Does any one knows any information about it.
    Any help will be highly appreciated.
    Thanks in advance and i want to wish you all a wonderful ,,,happy safe flying year .
    Best regards.
  • Beto Di Benedetto
    by Beto Di Benedetto 3 years ago
    Hi Demetri

    I'm George Di Benedetto from Argentina, we use BMW engines from year 2000, the best gearboxes are Rotax C and E type and in the second place the gearbox made by Takeoff in Germany.
    Maybe you can search who's the factory for this gearbox. Is first time see a bird stamped on the gearbox, nobody know form where is ti?
  • Gregg Ludwig
    by Gregg Ludwig 3 years ago
    The mechanical noise is a worn out spline coupler. The spline gear connects the engine output to the gearbox input. The spline gear takes a beating with the engine at idle. Pull the gearbox off and the problem will be obvious.
  • jay morgan
    by jay morgan 3 years ago
    If the spline gear fixes your problem then I wonder if a centrifugal clutch would be something to look at getting in a reduction drive. Wilfred at takeoff also offers them. Perhaps the slipping or neutral affect of a centrifugal at low rpm would reduce the pulsing or reverberation" if any" caused by the BMW boxer pistons pulsing directly against the prop inertia or lack there of at low rpm via the gearbox causing wear and tear. I have a 2003 BMW R1100S boxer with a 3.5/1 reduction drive with a centrifugal clutch built by Wilfred at take off. The centrifugal clutch would add little more weight and length hanging out the back so you mightneed to think about weight and balance again if you go that route. Let us know what you figure out.
  • DEMETRI NEOPHYTOU
    by DEMETRI NEOPHYTOU 3 years ago
    Hi guys,,,,,,
    Thanks for all your replies,,,,,,,,i will wait for more replies if possible from others to see different opinions.
    To be honest with you i didn't hear how it sounds,,,,my friend told me that theres a loud noise coming out,,,,is it from the gearbox OR engine i am not sure.
    I will go to his place to see it in live action very soon.
    Now,,,as i said i am flying a flexwing with a rotax 503 with B gearbox and truly below 2000 RPM theres also a loud noise that goes way when revving up.
    My gearbox and engine have only 120 hours since new and i don't have any problem with them,,,,both are working just fine.
    Now about this engine ,,,which it came from CANADA ,,,IT CAME WITH THE SUPPLIED GEARBOX AS NEW WITH THE bird STAMPED ON IT,,,,WE DON'T KNOW WHO THE MANUFACTURER IS FROM.
    Since we don't know i am not in a safe place to know if its USED or how MUCH it was used to justify the :@ The spline gear connects the engine output to the gearbox input. The spline gear takes a beating with the engine at idle.@
    So since we don't know we are not in a safe place to come up with conclusions !!!!!!!
    So if anyone knows who is the manufacturer of the gearbox this might help a bit to see how it works.
    Thanks in advance and i am looking forward to see some more answers.
    Best regards.
  • Gregg Ludwig
    by Gregg Ludwig 3 years ago
    Demetri, the problem described is most certainly a gearbox problem. Reduction gearboxes are easy to remove and open up for inspection but can take special tools to actually repair. I suggest that you remove the prop then run the engine at idle and the noise will likely be gone with the prop off. If you are having difficulty let me know and I will make a visit to help out if you like.
    While you are doing service could you please send me a picture of that nice muffler?
  • TL Triker
    by TL Triker 3 years ago
    Demetri, the gearbox looks like the SPG gearbox sold by Vassili at airtrikes.net, Canada. Take a look at the following links, they might have the information you are looking for. Fly Safe!

    http://airtrikes.net/spg2.htm

    http://airtrikes.net/engines.shtml

    Regards,

    Pedro
  • DEMETRI NEOPHYTOU
    by DEMETRI NEOPHYTOU 3 years ago
    Hello guys,,,,i am back AND THANKS FOR THE VALUABLE INFO YOU SEND........HERES WHATS NEW ABOUT THE NOISE:
    the noise is between 2100 and 2600 rpm where the vibrations of the BMW is at max. At idle it is OK. higher than 2600 is fine. The engine is new ( it was modified 5 years ego but did not work.

    The noise in the gearbox is metal to metal noise... like if there is a broken engine mount and the 2 metal parts are making noise... but it comes from the gearbox.. actually the coupling of the gearbox.

    My opinion is that the coupling of the gearbox does not have enough clearance and that resonant RPM the 2 metal couplings tough together. We would like to know if someone used the exact same gearbox from Airtrike (Canada) and had the same problem. We are still waiting for the response of the manufacturer... if we do not get any answers we will open the gearbox and investigate.
    LOOKING FORWARD TO HEAR FROM YOU ANY UPDATE???????
  • Abid Farooqui
    by Abid Farooqui 3 years ago
    Obviously that is some kind of resonance. Don't operate in that RPM range. Either set idle higher than 2600 or if you set it at lower RPM, don't stay in the 2100 to 2600 RPM, just transition through it really quickly.
  • Gregg Ludwig
    by Gregg Ludwig 3 years ago
    Unlike a Rotax gearbox the SPG gearbox housing can be removed without opening the actual gearbox. This will allow easy inspection of the gearbox coupler.
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