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Unread 20-05-2011, 11:55
Andrew Schreiber Andrew Schreiber is offline
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Re: 4" vs. 6" + 8" Diameter Wheels

Quote:
Originally Posted by Ether View Post
Yes, of course. That's why I said "comparable" in my post. Compare a 6" wheel that you would make for your robot to a 4" wheel that you would make for the same robot.

Worst case scenario, solid wheel made of 6061 Aluminum 1 inch thick. (I picked a type of Aluminum)

Code:
D (inches)	Moment (in^2*lb)
4	         2.44
6	         12.34
8	         39.00
I used (m*r^2)2 for the moment of inertia.

Once you start lightening it could get different since the amount of material you have to leave on the edge of the wheel doesn't scale with size so we would start treating it as a tick walled tube + however many support spokes you have. This starts getting a little more complicated but it is still doable. I am attaching an excel spreadsheet that (unless I did something stupid) should compute a rough estimate of the rim and spoke style wheels.

Edit: I had originally forgotten the width of the spoke so I was finding the area instead of volume, this has been fixed.
Attached Files
File Type: xls Moment Calculator.xls (24.0 KB, 4 views)
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Last edited by Andrew Schreiber : 20-05-2011 at 12:30.