I've got an arm attached to a shaft. The arms dimensions are 40x5 inches the arm weights about 10 lbs.
If I have a wind acting on the side of the arm, how would I translate the wind force into torque on the shaft?
To give some more information, I'm rotating the arm using a stepper motor, and I would like to know how to size the motor depending environmental conditions.
What should my formula look like in order to arrive a required oz-in of torque given my requirements being:
- I need to be able to accelerate the arm from 0 to 12 rpm in 1.5 seconds
- The wind speed can be as high as 30 mph
Using the formula P = .00256 x 30^2 i find the wind pressure per square foot being 2.304
Using the formula F = A x P x Cd for calculating force, I get 1.389 x 2.304 x 2 = 6.4
So I know that the wind force on my arm is 6.4 lbs. But now how do I translate this to torque on my arm?