Topic summary
tandem-rotor
Extracted from the Wikipedia article Tandem-rotor aircraft.
Design
Tandem-rotor helicopters have the advantage of being able to hold more weight with shorter blades, since there are two sets. However, the rear rotor works in the aerodynamic shadow of the front rotor, which reduces its efficiency. This loss can be minimized by increasing the distance between the two rotor hubs, and by elevating one hub over the other. Tandem-rotor helicopters tend to have a lower disk loading than single-rotor helicopters.