Quote:
Originally Posted by Ether
Would you please describe your latest shooter setup, to give some context to the numbers you posted.
How do you know it was 6000 ft/min, i.e., how did you measure that?
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We powered a 360mm circumference pulley off of a CIM at 12V, and measured about 5200rpm under no load (the tach actually pegged out, so we measured at 3V, 6V, and 9V and extrapolated). This gives a tangential velocity of 360mm*5200rpm/25.4/12=6100 ft/min.
We had about 12in of contact with the belt.
To measure exit velocity, we took several 60fps videos of the launch, and measured a 4ft travel out of the shooter in 6 or 7 frames, averaging about 2400 ft/min. The low frame count of course makes the uncertainty on this figure substantial (about 300ft/min per measurement, 100ft/min over 10 measurements).