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Thread: Good Websites for Newcomers

  1. #11
    to calculate inches per minute you times pi (3.141592) by the rpm of 1 motor and then by the diameter of the wheels in inches
    just a sec
    part 2 coming in a min

  2. #12
    OK that's inches per minute
    times by 2.54 to get cm a minute
    example. so 3.141592 x2,750rpm motors x 3inch wheels
    =
    25,918.2 inches per minute or 24mph
    but with 12inch wheels (30cm) it would do 98mph at top speed!

  3. #13
    OK so that's inches per min
    if I use
    2x 2,750rpm motors
    3 inch dia wheels
    then we do pi times everything
    2,750 (only 1 2750 having 2 motors does not mean you double it)
    x 3 (for the wheels in inches)
    x 3.141592
    that's 25,918.2
    or 24mph at top speed
    with 13 inch wheels it will do 98MILES PER HOUR! at top speed
    for a fw about 25mph is nice and fast

  4. #14
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    25mph but naff all torque, you generally need gearing for drive motors unless you have really tiny wheels.

    Also, 25mph is probably way too fast unless you have near light speed reflexes. For reference 12v drill powered machines (550ish rpm at the wheel) go between 5 and 6.25mph on the different sized blue wheels and are plenty nippy enough.

  5. #15
    I know this is kind of an old topic but I found this
    http://www.machinist-materials.com/comp ... astics.htm
    too much hdpe now and I think there are lots of alternatives

  6. #16
    Mouldy's Avatar
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    http://www.kjmagnetics.com/calculator.asp Magnetic force calculator... enter the magnet size and grade, and distance between the magnet and the object to be attracted and it will give you your attractive force in lbs.

  7. #17
    PJ-27's Avatar
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    A nice plastic comparison table:

    http://www.machinist-materials.com/c...r_plastics.htm

    Now if someone could tell me what each of the values mean that would be great.........

  8. #18
    THATS EXACTLY THE SAME AS MINE!

  9. #19
    Quote Originally Posted by archie2000
    I know this is kind of an old topic but I found this
    http://www.machinist-materials.com/comp ... astics.htm
    too much hdpe now and I think there are lots of alternatives
    there
    but i have no idea what anything means.
    I suppose I could had titled it better though

  10. #20
    PJ-27's Avatar
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    That it is! Sorry.

    Here's another to make up for it:

    http://www.simetric.co.uk/si_metals.htm

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