underscores in variable names cause horrible problems when you cut and paste equations. I think it'd be better to render them as underscores rather than spaces.

Secondly it is not at all obvious how to build units for torque - N.m.

Wrote

underscores in variable names cause horrible problems when you cut and paste equations. I think it'd be better to render them as underscores rather than spaces.

Yes, it was comented in previous posts.

Wrote

Secondly it is not at all obvious how to build units for torque - N.m.

Try using this:
'N*'m

Regards

Oscar