The CG range in single-rotor helicopters is

The CG range in single-rotor helicopters is

• A. More restricted than for airplanes
• B. Less restricted than for airplanes
• C. The same as airplanes
• D. Not defined

Answer: (A)

In a single-rotor helicopter, the balance range is tight because the way the helicopter is controlled relies heavily on the position of the center of gravity relative to the main rotor and the tail rotor. The main rotor provides most of the lift and its thrust line is far above the aircraft’s CG, so small shifts in weight location create pitching moments that the pilot must counter with precise cyclic and collective inputs. At the same time, the tail rotor must generate enough anti-torque to keep the helicopter from yawing uncontrollably, and the required tail-rotor thrust changes with CG position. If the CG creeps too far forward or aft, the needed control forces become extreme or the tail-rotor demand can exceed its limits, reducing controllability and safety.

Airplanes, by contrast, have lift generated by wings and rely on fixed control surfaces for stability and maneuvering. Their balance envelope is generally broader because the wing-tail arrangement provides more forgiving longitudinal and directional stability, and control effectiveness remains adequate over a wider range of CG positions.

So the center of gravity range for single-rotor helicopters is more restricted than for airplanes.