Flight controls translift


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Flight controls translift

  1. 1. INTRODUCTION TO FLIGHT CONTROL Three major controls during helicopter flight Collective pitch control Cyclic pitch control Antitorque pedals or tail rotor control Additionally the pilot must control the throttle* and monitor aircraft instruments. *Not all helicopters require constant throttle adjustment due to an engine “governor” Helicopter Flying Handbook 2012
  2. 2. COLLECTIVE PITCH CONTROL Located on the left side of the pilot Changes pitch angle of the main rotor blades As collective pitch control is raised there is a simultaneous and equal increase in pitch angle of all main rotor blades; if it is lowered there is a simultaneous and equal decrease in pitch angle The amount of movement in the collective lever determines the amount of blade pitch change Pitch angle changes the angle of incidence on each blade that a change also in drag which affect the speed or revolutions per minute (rpm) As pitch angle increases, angle of incidence increases, drag increase and rotor rpm decreases. Decreasing pitch angle decreases angle of incidence and drag, which will increase rotor rpm. “In order to maintain a constant rotor rpm, which is essential in helicopter operations, a proportionate change in power is required to compensate for the change in drag. This is accomplished with the throttle control or governor, which automatically adjusts engine power.” Helicopter Flying Handbook 2012
  3. 3. THROTTLE CONTROL Its function is to regulate engine rpm through fuel management Manually twisting the grip of the throttle will allow for maintaining rpm. In some cases a correlator or governor system helps maintain desired rpm when the collective is raised or lowered Twisting the throttle to the left (counter clockwise)- increases rpm Twisting the throttle to the right (clockwise)- decreases rpm Helicopter Flying Handbook 2012
  4. 4. GOVERNOR/CORRELATOR These devices help rotor and engine rpm and make adjustments to keep a constant rotor rpm. Once the rotor rpm is set, the governor (more fine tuning) keeps the rpm constant resulting in no need to make adjustments to the throttle (normal operations); the correlator is a mechanical connection that gives course rpm adjustments with collective movement. Helicopter Flying Handbook 2012
  5. 5. CYCLIC PITCH CONTROL Located in front of the pilot either between the pilot’s legs projecting upward from the cockpit floor or a “T bar” that swings downward Allows for control of flight of the helicopter; moving forward, rearward, left and right “Total lift force is always perpendicular to the tip-path plane of the main rotor” Its purpose is to tilt the tip-path plane in the direction horizontally desired The cyclic controls the rotor disk tilt Helicopter Flying Handbook 2012
  6. 6. ROTOR DISK TILT Rotor disk tilts in the same direction the cyclic pitch control is moved Cyclic moved forward- rotor disk tilts forward Cyclic moved aft- rotor disk tilts aft “Because the rotor disk acts like a gyro, the mechanical linkages for the cyclic control rods are rigged in such a way that they decrease the pitch angle of the rotor blade approximately 90 degrees before it reaches the direction of cyclic displacement, and increase the pitch angle of the rotor blade approximately 90 degrees after it passes the direction of displacement.” This is called gyroscopic precession. Helicopter Flying Handbook 2012
  7. 7. ANTITORQUE PEDALS Located in front of the pilot at the cockpit floor The pedals control the pitch and thrust of the tail rotor blades The helicopters fuselage and its rotation in the opposite direction of the main rotor blades require a counteraction and control. To compensate for the torque of the main rotor blade, a tail rotor or antitorque rotor is part of the design. The pedals allow the pilot to control the pitch angle of the tail rotor blades Helicopter Flying Handbook 2012