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RPM of a Flywheel

  1. Dec 28, 2014 #1
    Hey guys, new to the forum. I am wondering how to find what the maximum rpm of a flywheel could be. I was looking at stirling engines, and trying to compile all the equations that apply to calculate the rpm of the engine. I know the equation for the expansion of gas in the cylinders and the force applied to the pistons, however I know that as the flywheel starts turning, the energy carried with it and the continued force applied builds upon eachother until it reaches its maximum rpm. Excluding the impact of friction and drag, I was wondering how you calculate the max rpm.
  2. jcsd
  3. Dec 28, 2014 #2


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    Staff: Mentor

    Welcome to PF!

    I'm not sure you're asking the right question: excluding friction and drag, there is no maximum rpm for a flywheel. But why would you even care about that? Are you looking for the power output of the engine? It is a completely separate issue...
  4. Dec 28, 2014 #3
    Wow, gotta say, feeling pretty dumb right now, didnt even realize that until I wrote it out. And yes. I though if you were to hook stirling engine to sone type if generator, that the speed the motor rotates plays a factor.
  5. Dec 28, 2014 #4

    Doug Huffman

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    The maximum revolutions per minute of a flywheel is the rpm when the flywheel flies apart.
  6. Dec 29, 2014 #5


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    Google found..

    Not sure if this is out of date but...


    5000 km/h is about four times the speed of sound.

    Not exactly a flywheel but...

    The sphere was only 4 micron in diameter so although it was doing 600,000,000 rpm the tip speed was only 125m/s.

    Edit: I'll let someone work out the g-forces.
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