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3 bladed rotors- be gentle!

Discussion in 'General Discussion' started by PhantomFanatic, Nov 25, 2014.

  1. PhantomFanatic

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    Okay, this will seem stupid to many, so be gentle, please.

    I know that all helicopters, full scale and most small scale use a 2 bladed rotor. But, some planes use a 3 bladed propeller(s)

    I am not an aeronautical engineer, but an electrical engineer, which doesn't help with this question! Let's assume we have a 3 bladed rotor, with the same length, width and pitch as comes with the Phantoms. Let's also assume the drone has been modified to work with 3 bladed rotors.

    Con: I can see that there would be increased air resistance, (referring to rotation) higher weight and a greater load on the electric motors.

    Pro: Greater lift capacity per revolution. Hopefully meaning greater speed for the same battery depletion, if wind resistance isn't a big factor, which I don't think will be the case.

    It hasn't been done to RC multi-rotor drones, to my knowledge. Why not?

    Your thoughts, please.
     
  2. 750r

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    Like this ?
    [youtube]https://m.youtube.com/watch?v=R-vhQDsnoKA[/youtube]
     
  3. N017RW

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    The most common reason for an aircraft to use or require a 3, 4, or more bladed prop is reduced diameter. This increases ground clearance and for twin-engine designs increases cabin clearance.

    Since the diamater is reduced so is the blade tip speed. This combined with additional blades will reduce noise and produce more pulses per revolution thus raising the sound frequency which is typically less annoying.

    But to replace a 2 balde with a 3 blade. etc. requires some knowledge or testing to determine the proper pitch and diameter to gain performance while maintaining efficiency during different phases of flight. Improper substitution will have quite the opposite effect and lead to other issues with motors and ESCs.

    They do look cool!
     
  4. EMCSQUAR

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    Your question is not stupid, as a matter of fact many of us (including myself) tried them on first vers. Phantom 1s, back when we had prop nuts.

    The tri-blades were Chinese adaptations for multi rotors, were difficult to balance and created all kinds of strange flight conditions.They went by the wayside when DJI came out with spin on props.