R and L rotation 6 x 4 - 3 blade Master airscrew tested. Test rig Su-34

Discussion in 'Scratchbuilding!' started by Airflow, Jun 6, 2015.

  1. Airflow

    Airflow Top Gun

    Bench test data: 40 oz of thrust at 31A.
    Maximum is 32A for the TGY 2200kv
    Battery Zippy F-Max 2000mAh 4s
    2 oz more than the APC 6x4 2 blade prop. :) !
    that makes +4 oz of thrust for my SU-34 twin than with the old 6x4 APC E props.
    bye, bye APC 6x4E :)

    [​IMG]
    [​IMG]
    [​IMG]



    720 HD 30fps Flight test, with a great sound :D
     
  2. whatmovesyou

    whatmovesyou Top Gun

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    Did you modified your plane to protect your motor mount? The two blades(out of the three) sometimes caught the grass clumps on landing and would damaged the motor mount. So I went back to 2 blades for now. Will be interesting to what happens with yours over a number of flights.
    You mentioned 40oz of thrust using 31 amps.
    The APC you said gave 38oz, you did not mentioned the amperage, what was that?
     
    Last edited: Jun 6, 2015
  3. Airflow

    Airflow Top Gun

    Hello WMY
    Yes, I did. Glued on a Depron piece (additional grass protection) the same way as I did to protect my SU-30. And it has worked well so far ( 2-blade 6x4) on both of them. but yeah... We'll see how well it works with 3-blades, may soon get stuck in the grass... ;)

    The Max Amp. when on the 2 blade APC 6x4 = 28A
    VS 31A with the Master Airscrew 6x4/3 blade prop.

    [​IMG]
     
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  4. quorneng

    quorneng Ace Pilot

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    Actually what you have demonstrated is that 3 blade props are less efficient!
    If 28A gave you 38oz thrust then from 30A you should have got 43.4 oz thrust rather than just 40.
    Of course if you have a diameter limitation than more blades will give more thrust but it requires a disproportionate amount of power to achieve it. ;)
     
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  5. Airflow

    Airflow Top Gun

    quorneng, You are partly right, but nobody can figure out specifically (43,4 oz !?) how much power it would give you.
    There are many factors to consider, an old battery, well used motor etc ...
    Even the type/brand of 6x4/3 propeller.
    but efficiency is not all, you get a better stability with three blades, and more thrust at low speed/rpm.:)
    28 VS 31A does not make much difference at full throttle, and I rarely use full throttle. In any case, it does not matter to me, I'm not a full speed aviator...

    (if not absolutely necessary, just for a short while to get out of difficult situations...) ;)
     
  6. whatmovesyou

    whatmovesyou Top Gun

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    Do you have any plans to try it out on a alpha jet?
     
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  7. Airflow

    Airflow Top Gun

    No! but now I got it ... Typical! why would you mention it now? Summer is not the right season for starting up new projects...:confused:
     
  8. Baufritz96

    Baufritz96 Ace Pilot

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    Are those zip ties the only thing that hold the motor mount to the plane? Or do you glue it as well?
     
  9. Airflow

    Airflow Top Gun

    Baufritz,
    No glue! zip ties are more than enough, they pop off before something else breaks.
    Here is an example... First attempt with zip ties, motor mount intact, just the motor popped off... when the prop got stuck in the catapult wire. lol :D

    F-22 V2 Screws and glues are banned several years ago. ;-)
     
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  10. TomMonton

    TomMonton Top Gun

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    lol. .. fun stuff. The motor let go right out of gate too. .. never had a chance.

    Slo-mo capture sure takes the mystery out of "what happened".
     
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  11. Airflow

    Airflow Top Gun


    Yes, I got the idea to use zip ties by David Windestal (RCexplorer) and his Tricopter motor mount.



    [​IMG]
     
  12. TomMonton

    TomMonton Top Gun

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    Slick idea actually. ..especially if you can control your "point of failure" to let go without trashing the rest of your plane.

    I've been using the black ones, they offer a better UV rating and why we stock them specifically.

    I think I'll move over to the small white and/or colored ones because they break down quicker.

    Thanks Lars :)
     
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  13. Airflow

    Airflow Top Gun

    Yes Tom, the scrawny colored zip ties are of rather poor quality, and they are perfect for this purpose! Good luck!
     
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  14. whatmovesyou

    whatmovesyou Top Gun

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    I don't know about you, but to keep things interesting, I always have 5-6 projects going on at all times. Now that the rudderless x-47b is finished and flies, I have my oblique wing to explore(have about20 degrees for and aft and flies), Vtol, A-10 EDF jet, gas 50cc and my new prop thrust vectoring to fly.

    That's why I wanted to see with the 3 bladed prop, what kind of flow you had across the surfaces and if you tried it on more than one plane. Could care less about efficiency, more about thrust and flow patterns. Reason for asking initial question was to see if I need to change the ESC in amps.
     
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  15. Airflow

    Airflow Top Gun

    Well, I have around 6-8 ... projects running simultaneously, mostly repairs or modifications of old planes, FRC MiG 288, the Su-37 mk2, RCP V4's, the MiG-29, SU-30. Even a J35F project that has been standing still for a while.. two years... And finally two balsa plane.
    And I will try the 3 blade Master airscrew prop on most of my planes, as soon as they are ready to be flown.
     
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  16. DavePowers

    DavePowers Administrator

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    Airflow, what a great set up!
    Design the plane AROUND the prop is what I always say.
    It looks/feels so soft and easy to fly. Great testing.
     
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  17. TomMonton

    TomMonton Top Gun

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    Just put a little hot glue on those. ...

     
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  18. Airflow

    Airflow Top Gun

    That's a good point, will copy that!
     
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  19. Airflow

    Airflow Top Gun

    Thanks Dave! and can only say, your previous assertions on this topic now turns out to be correct!
    Motor/s close to the control surfaces are good for stability and immediate response.
    And one or two 3 blade prop/s makes it even better/easier.
     
    DavePowers likes this.
  20. Airflow

    Airflow Top Gun

    First attempt, the 3 blade propellers are now spinning in the opposite direction... outwards instead of inwards.
    And it feels even better, at least on a Su.

    [​IMG]

    720HD 30fps
     
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