Dark Horse RC Heli Power & Setup Calculator (online)

Windows head speed calculator (download)

Head speed calculator (online)

A webpage with a huge amount of interesting r/c links

My special thanks to the following useful websites:

http://digitizeit.de/heli                
Heli-Headspeed, RC-Model Helicopter Tachometer Software
http://www.rchelicopterfun.com        
From toy to turbine, this site provides information and guidance to help you succeed with RC Helicopters
http://www.compassmodel.com
Leading The Way
http://www.heliflightcenter.com        
Heli Flight Center is dedicated to provide value, service and enjoyment to its customers
http://www.helifreak.com                
Fun, learning, friendship and mutual respect
http://www.rcheliaddict.co.uk        
Your Friendly Rc Helicopter Community
http://www.helidancers.com        
Helicopter interest group of Norway