A number of people have asked questions about the Pro-Drive secondary.  In order to provide information to the RotorWay community a few of these questions have been included in the following Frequently Asked Questions (FAQ).

What steel does the Pro-Drive Secondary use?

The Pro-Drive Secondary uses 9310.  9310 has excellent hardenability for operation under the sprag clutch and has moderate strength throughout the remainder of the shaft.  Other steels were considered, but the change to a higher strength material also leads to a potential increase in brittleness.

Fretting occurred under the bearing and under sleeve, what have you done about the sleeve?

The Pro-Drive Secondary system eliminates the sleeve.

Does the belt have higher tension then the chain?

There is a perception that the Pro-Drive belt causes significantly higher loading on the secondary shaft then RotorWay's chain drive.  It is important to understand that the chain or belt typically generate about 2200 pounds of tension during hover.  While the chain has little stretch, the belt will stretch more then 1/4 an inch under that load.  While the belt does contract during an increase in temperature, that stretch is typically less then a few thousands of an inch.  Therefore, the tension in the belt, even after extended operation, should never be as high as the tension during normal operation. 


If you have any more questions, please send us an email or call, we are happy to help.



John Spurling, Pres.
Route 3, Box 12 C
Cleveland, OK 74020, USA
Tel. (918) 243-7635
Fax: (918) 243-7882