Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Thrust from Propellers

  1. May 12, 2005 #1


    User Avatar

    can anyone tell me how to calculate thrust for a model airplane. i know the propeller size and pitch and also the engine power and RPM.

    Any help would be much appreciated

    regards reg_ram
  2. jcsd
  3. May 12, 2005 #2


    User Avatar

    Staff: Mentor

    Well, the simplest way would be if you know the rpm, you can multiply pitch by rpm to find the velocity of the air, then use bernoulli's equation to find the pressure (and multiply by surface area traced out by the prop to find thrust).

    The reality is probably a little tougher: rpm will vary with the speed of the plane - the faster the plane goes, the easier it is for the prop to spin. What ends up happening is that the horsepower generated remains roughly constant while rpm changes.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook