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Thread: RC Helicopter

  1. #1

    Default RC Helicopter

    Hi Guys,

    I was trying to make a RC helicopter but found that that what ever I do the rotor doesn't produce enough lift.

    Has anyone tried this project.

    Regards,

  2. #2
    Administrator T-1000 rao's Avatar
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    aerodynamic modelling requires a lot of expertise.. cant waste time on modelling.. so I bought an RC chopper off bazee and played with it ..

    Rao

  3. #3
    Administrator T-1000 vikas's Avatar
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    me 2 ... bought one cant waste time on what im interested in .

  4. #4
    Super Moderator T-1000 docel's Avatar
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    1. :lol: :lol: :lol: guys :!: :!:

    2. What motor? What rotor?
    3. Total weight of it all?

    If none of above known, then replies 2,3;
    else write, post pic;
    docel
    ^Anything is possible..
    after YOU prove it!!

    http://bangalorerobotics.tripod.com

  5. #5

    Default RC helicopter. More time

    Hi,

    As Rao said it is really difficult to make helicopter as it requires lot of expertise in airodynamic field.

    Motor I am using is from the CD rom drive but think it is heavy for the lift the rotor is producing.
    Somehow I feel that the rotors I made are not in the airfoil shape and is producing the forces in opposite direction. But I don't have anyting to test my assumption. I tried using smoke to see how air is flowing but got a mixed observation.

    I am gonna spend some more time on this. Will let u people know if I get some positive output.


    Regards,
    Kiran

  6. #6
    Super Moderator T-1000 docel's Avatar
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    Hi kiran,
    You need at least 5A in the CD motor and must be geared for abt 800- 1500 Rpm. Try 2 to 5 degree pitch of the rotor.
    quite easy to make rotor blade, if you have patience.

    It is the Rotor that develops Lift contrary to what people generally think.
    Produce an aerofoil with Flat bottom, 25% chord and tilt about 5 degrees.
    Chord is the thickest part. the leading edge (front) should be blunt and the Trailing edge should be sharp. The width should be 30% less at the edge.
    docel
    ^Anything is possible..
    after YOU prove it!!

    http://bangalorerobotics.tripod.com

  7. #7

    Default RC Heli : Measurements..

    Hi Docel,

    I have made the rotor blades using a light weight material used for making name plates. I tried to give the shape of airfoil as u mentioned but I am not sure about the accuracy.

    Rotor dia : 12 cm. (2 baldes)
    I have made the blades using a same strip, rather than making 2 different blades, and have drilled it in the middle to mount it over the motor. I am not using any gears.

    The rotor motion is prducing a spin but isn't producing a lift. For this I extended the body using a scale. After using a scale the spin is reduced but there should have been some lift at least.

    Is there any problem in the way rotor blade are made ? I have gone through Bernoulli theorem and thought that just by making the upper portion of wing thicker will generate the lift. I don't know where I am going wrong.

    Anyhow I will try to make the blades using the measurements you have provided.

    Can I get some more information on blades and motor to use for making a heli with body of size 3 match boxex (one over the other) and body length equal to 15 cms (a small plastic scale).



    Regards

  8. #8
    Super Moderator T-1000 docel's Avatar
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    Hey, thats too heavy :!:
    The CD rom motor cant handle it. To be funny, the rotor should CUT your finger while it is turning :lol: That is when it will generate any useful lift.

    A rubber band motor is the strongest you can make for flying, with the minimum weight.

    Im in a hurry: will post a blade diag. in the afternoon.
    docel
    ^Anything is possible..
    after YOU prove it!!

    http://bangalorerobotics.tripod.com

  9. #9

    Default

    [quote="docel"]Hey, thats too heavy :!:
    To be funny, the rotor should CUT your finger while it is turning :lol: That is when it will generate any useful lift.
    quote]

    It did not cut my finger. he he.

    By the way what are the specification for motor and RPM required to generate such a lift. Say just to lift the motor and rotors. Is there some equation which equates weight with the rpm ?

    Thanks

  10. #10
    Senior Member Android
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    Default Helicopter

    Hello Kiran,
    Maybe you can checkout this link for help:
    http://www.seattlerobotics.org/encod...r/bxflyer.html
    As far as I have seen, electric-helis use motors with rpm in excess of 20K to 25K and geared down appropriately.
    If possible, try using ready-made prop blades available for electric rc planes. If you dream of bulding a 1 rotor (plus the tail rotor) heli, then best luck in your efforts, you are on your own. 4 rotor heli should not be a big problem though.
    Cya,
    Mohit Bhoite
    http://mobots.solarbotics.net

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