I'm thinking about cobbling together something that will involve the use of a flexible drive shaft. I've found several manufacturer's web sites with specs about max torque. But not much about RPM.
I figure that max RPM (for most applications around 3600, maybe up to 10K) is dependent on friction losses. Which are dependent on bending radius.
Anyone have a link to some simple design rules (I'm not an ME) for flexible shaft applications and RPM/friction losses?