An analytical and experimental study of the effect of periodic blade twist on the thrust, torque, and flapping motion of an autogiro rotor:
http://aerade.cranfield.ac.uk/ara/19...report-591.pdf

An analysis of the factors that determine the periodic twist of an autogiro rotor blade, with a comparison of predicted and measured results:
http://aerade.cranfield.ac.uk/ara/19...report-600.pdf

The aerodynamic characteristics of full-scale propellers having 2,3,4 blades of clark Y and R.A.F. 6 airfoil sections
http://aerade.cranfield.ac.uk/ara/19...report-640.pdf

A simplified theoretical method of determinig the caracteristics of a lifting rotor in forward flight:
http://soliton.ae.gatech.edu/people/...report.716.pdf

Hovering performance of a helicopter rotor using NACA 8-H-12 airfoil sections:
http://ntrs.nasa.gov/archive/nasa/ca...1993083901.pdf