A bit of information on my chosen design.
I still have to finish the blade straps, feathering pitch links, teeter stops, teeter bushes and shims and a few other things before any rotor testing can commence.

The engine will be run with a 12v pump supplying cold water for now, I have made a prevision for a belt drive fan off of the flywheel when a radiator is finally mounted for onboard cooling. Also I won't be making any Yaw controls until the blades have been run up and have proven lift capability.

Getting the rotors up to flight Rpm will be the first challenge, I will obviously balance the blades but I think it would be some miracle if they ran smooth straight away.

My day job is welding on classic cars, if anybody is interested my new channel is:
   / @bensclassicbodywork