1. Not finding help here? Sign up for a free 30min tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Motorcycle Intertia Dyno - Moment of Intertia for various objects?

  1. Dec 30, 2004 #1
    Hi all,

    Firstly - I'm not a collage student but this seemed a good place to ask the question! Any help welcome :smile:

    As a fun home project, I've been building a motorcycle dyno, connected to a PC via a custom made PIC based device. Have most of it worked out with regards to data collection, ignition reading from the bike, etc.

    Was planning to make a dyno drum from one solid piece of steel, thus making the physics easy with regards to moment of Intertia (simple solid cylinder) - but steel is (now) very expensive, so I wanted to make a steel hollow drum, but filled with 'something' to give it weight for the motorcycle to work against. I was thinking possibly concrete because it's cheap & heavy - with the drum sealed as a solid unit once the concrete was solid.

    I would know the exact dimensions & weight of the steel used to create this hollow drum - but how would I use the dimensions of the concrete in the physics?

    Would I have to weigh the drum before filling? Then fill it & allow the concrete to set & weigh again? Then seal the end of the drum and weld it shut & wiegh again for a final total?

    That would give me weights before and after - but what does concrete weigh per cm3? Arggh! (they told me I would actually use physics once I left school & I didn't believe them! :wink: )

    Umm...advice welcome!

  2. jcsd
  3. Dec 30, 2004 #2


    User Avatar
    Science Advisor
    Homework Helper

    can be quite handy.

    Regarding the density of concrete, you're more or less on your own. How much concrete weighs after setting can vary a whole lot since concrete is, after all, a mixture of various things.

    Really, I would suggest that you worry about balancing the drum first. Once you have that, you can use a known force to measure the moment of inertia.
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?

Similar Discussions: Motorcycle Intertia Dyno - Moment of Intertia for various objects?
  1. Braking motorcycle (Replies: 3)