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- Thread starter batmx3man
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rcgldr

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Power = force times speed.

In English units to calculate horsepower given force and speed:

power/hp = force (lbs) x speed (mph) / 375 (conversion factor).

You can ignore the gearing factor, since it's assumed that you gear the car so peak power occurs at top speed, so the rpm, torques, ... don't need to be known. You'll need to estimate drivetrain and rolling friction losses and reduce the peak power by this amount, usually 15% loss is a good estimate for cars with manual trannys. The next problem is calculating aerodynamic drag, which will be related to cross sectional area times coefficient of drag times speed^{2}.

In English units to calculate horsepower given force and speed:

power/hp = force (lbs) x speed (mph) / 375 (conversion factor).

You can ignore the gearing factor, since it's assumed that you gear the car so peak power occurs at top speed, so the rpm, torques, ... don't need to be known. You'll need to estimate drivetrain and rolling friction losses and reduce the peak power by this amount, usually 15% loss is a good estimate for cars with manual trannys. The next problem is calculating aerodynamic drag, which will be related to cross sectional area times coefficient of drag times speed

Driven wheel force = wheel torque divided by effective radius of tire. Wheel torque = engine torque times overall gear ratio (times effeciency factor, 85% is a reasonable esitmate).How do I convert the torque of power the engine is sending to the wheel into a force?

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