Pinewood Derby® Engineering Data

wheel

1) BSA® Style Wheel Modifications: bsa_wheel1.pdf

axle

2) BSA® Style Axle Modifications: bsa_axle1.pdf

block

3) BSA® Style Standard Block Dimensions and Mass Properties: bsa_block.pdf

unmod

4) BSA® Style Unmodified Car Dimensions and Mass Properties: bsa_assembly1.pdf, template3.pdf

5) Tungsten Car Weight drawing (tungsten.pdf)

6) Pinewood Derby Physics (Where to put the weight)

  • Density of Lead (Pb) = .4097 lbs/in3 (lead is toxic – limit your exposure). Click here for more about lead and where to get it.
  • Density of Tungsten (W) = .697 lbs/in3   Notice that for a given volume, tungsten is much heavier than lead.   This allows you to concentrate the weight exactly where you want it (Note: tungsten welding electrodes marked “thoriated” contain slightly radioactive thorium, don’t grind them) Click here for more about Tungsten and where to get it.
  • Density of Pine = 0.01381 lbs/in3  Note: This number should be taken only as a guide.  The density can vary widely depending on factors including growing season conditions, relative humidity, and other conditions.

Note: Engineering data is believed to be accurate, but is not warranted in any way. Always use your best judgment, and verify weights.

Always check your build with a good quality kitchen scale to be sure you are close.  A scale is probably the most important tool when building your car.

1 comment for “Pinewood Derby® Engineering Data

  1. October 6, 2014 at 10:48 am

    Love these ideas for the wheels and axles. But I do have a question. Does anyone reading this know. What the I.D. Of the wheel axle hole is. Supposed to be. I would like to purchase a reamer that size.

    Thanks,

    Paul
    Cincinnati

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