Anonymous asked in Cars & TransportationAircraft · 2 months ago

Why does a larger propellor pitch/size = less thrust?

5 Answers

  • Anonymous
    2 months ago

    Larger prop or more pitch = more drag and needs more power to turn it.

  • Zack
    Lv 7
    2 months ago

    Not necessarily true.

    As your propeller size/pitch increases, the prop becomes harder to turn due to increased air resistance. If the engine is powerful enough, the propeller will generate more thrust than a smaller propeller. However, if the engine is under-powered, the propeller will spin too slowly and not generate as much thrust as a small propeller would.

  • Anonymous
    2 months ago

    As the propeller size increases, the RPM's are cut back because large prop tips become ineffective when they exceed the speed of sound at the prop tips. This is also why large steam turbines can only be manufactured to their current size, because the turbine rotors are only efficient up to the speed of sound and can not be made larger then they are or they will have cavitation and free spin in a self induced vacumme.

    This is why large airplane propellers are often coupled to the engine with a planetary reduction gear box.

    The same goes for a turbo prop, the turbine engine transfer turbine is connected to a planetary reduction.

    • Anon2 months agoReport

      Props coupled to planetaries ONLY when hi RPM engine used--like, a Subaru. Not a Lycoming which redlines at 2800. UR confusing constand speed drive boxes with reduction gears.

  • 2 months ago

    Because your motor has no power

    • P & W2 months agoReport

      Aircraft engines that turn propellers are rated in shaft Hp. So, what are gas turbine, turbofans, and ramjets rated at ? If you have to look it up, you don't Belong here. As said a mistake with a Mitsubishi is, My Bad. With a 787, 400 + deaths..

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  • Anonymous
    2 months ago

    not true , depends on the torque of the engine there is always an optimum specification for each engine

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