twisting rotorblades

[downwash]

i plan to build rotorblades by machineing a main spar and have a ribbed tail section.how to twist? my original plan was to twist the billets befor machineing and let them return to there natral state. but i beleive this would be difficult to yeild reliable results. can they be made strait and then bent? would that comprimise the strength? many production blades almost all are twisted. how is this done? any thoughts sugesstions or knowlage would be awsome thanks

 

[klyde]

Vertical Aviation, the home of the Hummingbird helicopter and a blade repair facility for the S52 helicopter has a blade twist jig that looked relatively simple. Try

http://www.verticalavition.com

The twist is very beneficial in load lifting. Ray Prouty has told one helicopter manufacturer that an 8 degree linear twist would allow them to pick up 43# more than the straight blades, with all else being equal. This is on an 1500# gross wt. helicopter.