Aeronautical Science Perspective on Helicopter Flight Controls

Aeronautical Science Perspective Paper

Jack Jasper

Embry-Riddle Aeronautical University

Introduction to Aeronautical Science, ASCI 202

Rotary-wing aircraft such as the SH-60B are designed with features meant to assist the aircraft in meeting a multi-mission requirement including anti-submarine warfare (ASW), anti-surface warfare (ASUW), naval special warfare (NSW) insertion, search and rescue (SAR), combat search and rescue (CSAR), vertical replenishment (VERTREP), and medical evacuation (MEDEVAC). (“MH-60R Acquisition Report,” 31DEC2011) Such features include a fully-articulated rotor head; four; two main landing gear wheels and one tail landing gear tire; two T700-GE-401C turbo-shaft engines. All of these factors affect the aerodynamic properties of the helicopter; the flight controls and how they control pitch, roll, and yaw are driven by the design of this particular layout. All helicopters have three basic sets of controls. The flight control systems on this particular aircraft are hydraulically power-boosted mechanical control systems. ("Interactive Electronic Technical Manual," 2010) Both the lateral and longitudinal control of the aircraft are achieved using this system. The cyclic controls the pitch of the rotor system by moving specific blades at predetermined locations within the rotation of the head thereby changing the pitch and roll of the fuselage. The collective changes the pitch of the all the blades at once changing the angle of attack providing lift or reducing it accordingly. Additionally, adjusting the collective changes the amount of torque from the main rotor causing the fuselage to yaw left or right. Due to the torque from that main rotor the rudder pedals change the pitch angle of the tail rotor paddles, which provides control in the yaw axis.

The pilot’s inputs to collective and cyclic controls are transmitted to the rotor blades through a complex system of pushrods, linkages, bellcranks, pilot-assist actuators and servos, a...