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  1. #1

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    Impeller leading edge and trailing edge question

    Example....

    I have a 16/23 impeller... if I change the leading edge to 15 will that change MAX RPMS?

    If I leave the leading edge alone and change the trailing edge will that effect hole shot??


    What is the ideal hole shot situation? Spin up to target RPMS and then down a couple hundred and then back up to target? OR

    Spin up to under REV LIMITER RPMS, down a couple hundred then up to target RPM?
    Last edited by pdxrealtor; 08-25-2009 at 01:25 PM.


  2. #2
    TERRY bigbuck12345's Avatar
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    send it to jerry aka greenhulk and let him know what you are looking for

  3. #3
    CHANDY's Avatar
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    From what I understand is that the lower the initial number is the stronger the holeshot but I don't know what effect it has on the top end. Obviously amount of power you have to turn the prop and the number of revs you can get it to spin all play a factor and it seems that I will be digging in the pocket and continuing to experiment with different combos. The only problem with that is that I can't do same day testing cause it is at least a week or more from when I send prop away to get it back and then the weather comes into it cause it will be different to the last time I was out testing.

    I have been wondering what effect changing the leading edge on props does to holeshot and top end myself. As I live in australia it would be handy to know so I can do it myself as it can get expensive sending props away all the time to find that a certain combo doesn't work.

    I will be watching this thread with great interest

  4. #4

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    Bump

  5. #5

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    bump

  6. #6
    ROTAX RACING performance
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    Les allready told you to get a new prop , that skat trak is wast of time , even in my turbo setup i would not be able to spinn that prop, extrem bad accelleration and no topspeed as well.

  7. #7

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    Quote Originally Posted by mrracing View Post
    Les allready told you to get a new prop , that skat trak is wast of time , even in my turbo setup i would not be able to spinn that prop, extrem bad accelleration and no topspeed as well.
    I'm trying to learn about the technicalities of the prop, whether it is 3 blade or 4 blade.... that's all.

    Les didn't say get rid of the prop, he said pitch it down.

    The reason it was pitched so high was we started out with a 3 blade that had to be pitched up to 15.5/22.5 BEFORE the re-map and B-Kit. Then after the blower and remap I was on the limiter.

    In the mean time the hub cracked so Skat replaced the prop, which turned out to not give the same results at such high pitches.

    Skat was scratching their heads as to why I was pulling that steep prop, but I was.

    NOW-- can anyone help with the O question?

  8. #8
    cheatin' piston popper addicted's Avatar
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    usually, you increase pitch on the leading edge to get rid of cavitation, then bend the trailing edge to dial the top end rpm's. bending the leaning edge does affect max rpm, but not as much as the trailing edge. However, the transition between pitches, wear ring condition and nozzle size factor in as well. make yourself a prop bending jig and learn how to do it youself. once you get it where you like it, send it to a pro for cleanup and balancing.

  9. #9

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    Quote Originally Posted by addicted View Post
    usually, you increase pitch on the leading edge to get rid of cavitation, then bend the trailing edge to dial the top end rpm's. bending the leaning edge does affect max rpm, but not as much as the trailing edge. However, the transition between pitches, wear ring condition and nozzle size factor in as well. make yourself a prop bending jig and learn how to do it youself. once you get it where you like it, send it to a pro for cleanup and balancing.

    Thanks for the info-

    So a change in the leading edge could/would effect max RPMS?

    A change in the trailing edge will NOT effect the leading edge?

    By Jig do you mean a prop removal tool?

    I just went and had office depot do up the pitch gauge chart on transparent paper for me so I will have not only a MM ruler, but the pitch gauge as well.

    I bent my first prop last night - 2mm on the trailing edge. It was on an extra 4 blade I have and was down 200-250 rpms. I think I did a good job... I measured 1 inch from trail edge, at trail edge, have way between leading and trailing and all were measuring perfectly aligned when I was done.

  10. #10

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    Oh ya...

    On bending the leading edge 2 questions-

    1) where do you grab the blade?

    2) Opposite from the trail edge, bending towards nose cone INCREASES pitch correct?

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