[Simon G]

Thanks for the detailed reply. It was very helpful. We actually looked at a similar design here at Sikorsky a while back for large scale helicopter applications...!

One more question. Your current worm lead angle is very close to 10 degrees (9 deg, 24' to be exact), which would give you backdriving in extreme conditions, especially with your smooth, ground worm...

Why didn't you use a single thread worm and a 30 tooth gear instead? (thus cutting your lead angle)

Was it a geometry (packaging) issue, or am I missing something critical? Your worm shaft thrust would go up with a smaller worm gear, but the torque requirements would be the same, right? Does the efficiency drop with a smaller lead angle? Is there a limitation on RPM with a single thread worm too?

Thanks!
Simon