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Thread: Lift problems

  1. #1
    Less than 10 posts so far!
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    Unhappy Lift problems

    I have just built an eagle 1 with a 600cc 4 cylinder bike engine , it has a 900mm 9 blade fan with a 45 decree pitch. Had a test run last night , front end lifted at about 8500RPM (engine ) but back end lift and thrust at about 10500 (engine screaming) if I increase the pitch would it give more lift and less revs, Can anyone help.

  2. #2
    Forum God > 400 posts
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    Default Re: Lift problems

    Sounds to me that you go a ratio problem, with that amount of pitch on the blades, the engine should not be able to rev that high. Any pictures available?
    In the beginning there was the Cube; I know where is came from and it has the power to create Hover life. But with great power comes great Fun.

  3. #3
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    Default Re: Lift problems

    Quote Originally Posted by atters View Post
    Sounds to me that you go a ratio problem, with that amount of pitch on the blades, the engine should not be able to rev that high. Any pictures available?
    I have attached two pictures, I sent all the info for the gearing of my engine to Ken at K&M Products and he sent me all the parts required and told me to run it in third gear, I tried 4th 5th & 6th gear but not much better.
    Attached Thumbnails Attached Thumbnails Click image for larger version. 

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  4. #4
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    Default Re: Lift problems

    If your splitter plate is correct and you bulit the hover to the plans, then I agree with Atters, it must be a gearing problem. How many teeth does your belt pulleys have on them (drive & driven)?

  5. #5
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    Default Re: Lift problems

    Hi,
    You have to consider that the weight is your enemy.
    What is the weight of your engine?
    Which is its power curve and to which rotation speed?
    On photos it seems that you use a multiwing 5Z blades.
    For me the optimal rotation speed of your fan is 2000 rpm
    It is possible that your ratio is not correct.

    regards

    idefix

  6. #6
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    Default Re: Lift problems

    Thanks guys, I have just spoke to Ken and it looks like I've set the pitch all wrong, I will try it tonight and let you know how I get on, sorry for wasting your time, "novices" who needs them ?

  7. #7
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    Default Re: Lift problems

    Novices! The Club needs them. Never be afraid to ask.

    Jim

  8. #8
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    Default Re: Lift problems

    No worries mate, I had the same trouble with a 400cc honda engine I had, Found that it needed to be in the highest gear there was, either 4 5 or 6, I eventually dumped the bike engine for a Rotax 503.

    Hang in there, I think the 600cc you have could work well and looking at the pics you have done a great job so far.
    In the beginning there was the Cube; I know where is came from and it has the power to create Hover life. But with great power comes great Fun.

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