Plasma Attempt #2

[Robin Hewitt]

use the formula torque=angular acceleration * moment of inertia, where acceleration is in rad/s^2.

In post #4 I calculated the moment of inertia of your 10g (well not quite, see below) tube using the formula, courtesy of Wikipedia:

I'm sorry to do this to you, good try and all that, know you only want to help, but you can't bamboozle me with your arithmetic and Wiki-whatsit

force = mass * acceleration

If you want torque you add a distance component

Torque = mass * acceleration * radius

Of course the acceleration here is peripheral acceleration, not radians/s/s

If you insist on radians/s/s and moments of inertia... One turn is 2 pi radians and moves you by 2 pi radius so they simply cancel out after you have gone all the way round the houses.

The 1/8" wall tube weighs 2.35 kg, the peripheral acceleration is the same 2.94 m/s/s as the gantry, the worst case radius is 0.019 m

2.35 * 2.94 * 0.019 = 0.131 Nm

But geared 3:1 down the motor only needs to find an extra 0.044 Nm