Page 208 - Aeronautical Engineer Data Book

Aircraft design and construction 167
Single main and tail rotor
(general purpose helicopter)

Twin co-axial rotors
(shipboard helicopter)

Counter-rotating
rotors

Twin intermeshing rotors
Inclined shaft

Twin tandem rotors
Counter-rotating
(transport helicopter)
meshing rotors

Fig. 10.7 Helicopter configurations

to overcome the force of gravity, and overall
specific fuel consumption (sfc) is high. Figure
10.8 shows how sfc is gradually being reduced
in commercial helicopter designs.