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Joined: 16 Mar 2008 Posts: 6
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Posted: Fri Mar 21, 2008 7:26 pm Post subject: How things are calculated |
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Hi
The way this works is (currently) fairly crude.
The points entered in the power curve are all converted to torque in lbft and rounded to 2 decimal places. Once everything is entered these points are used to fill in a working series with power ever 100rpm (so if you enter power every 100rpm that is as accurate as it is going to get).
Thrust is calculated from the torque and the gearing. Basically torque (in lbft) * primary drive ratio * gearbox ratio * final drive ratio all divided by the radius of the driving wheel in feet (including tyre).
Apologies to those who want to think in metric.
Drag is calculated from 0.5 * CdA * Density of Air * speed squared all divided by the acceleration due to gravity. The density of air is taken as a constant of 0.0801. Acceleration due to gravity is taken as 32.1 (imperial figures again).
More details are here:-
http://www.peterverdonedesigns.com/gearing.htm
All the best
Keith |
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