The Supersonic Rotor Helicopter | Hush-Kit
Lost to history: The Bell HSL-1 - Vertical Mag
Check out the double-rotor helicopter that could be the US Army's next Black Hawk
aircraft design - How can a helicopter be designed without a tail rotor? - Aviation Stack Exchange
aerodynamics - Number of blades in a helicopter rotor - Physics Stack Exchange
K-MAX Helicopter With Two Crossing Rotors Is Lighter And More Efficient - YouTube
Are two rotor heads better than one? - Model Airplane News
Helicopter Rotor Systems Configuration | SKYbrary Aviation Safety
9 Helicopter Two Blade Main Rotor Stock Video Footage - 4K and HD Video Clips | Shutterstock
Aerospaceweb.org | Ask Us - Tailless Helicopters and Torque Effect
CH-47F Chinook Block 2 moves toward production, without advanced rotor blades - Breaking Defense
V-22 Osprey Tilt-Rotor - Helicopter & Airplane Combined - YouTube
Tandem rotors - Wikipedia
Boeing CH-47 Chinook - Wikipedia
Coaxial rotors - Wikipedia
auto rotation - Is it possible to fly a tandem-rotor helicopter after a single rotor failure? - Aviation Stack Exchange
Twin rotor helicopters hi-res stock photography and images - Alamy
33 Things You Probably Don't Know About the CH-47 Chinook
Transverse rotors - Wikipedia
Aerospaceweb.org | Ask Us - Largest Helicopter in the World
MH-47G Block II: New Heavy Lift Helicopter for US Commandos
SimplePlanes | Types of helicopters (and how they work)
Heavy Lift Helicopter Fleet | Columbia CH-47D, Columbia 234 UT, Columbia 234 LR, Vertol 107 - II | Overview, Learn More | Columbia Helicopters
