Primary Flight Controls

Primary Flight Controls

1. Ailerons

   • Two ailerons used to roll
     • One deflects up, other deflects down
   • Large aircraft only
     • Roll spoilers supplement ailerons
   • Up deflected aileron and extended roll spoilers create a down going wing
   • Some aircraft have inboard and outboard ailerons
     • Both used for for low speed flight
     • Only inboard required during high speed flight
       • Outboard ailerons inactive during high speed flight

2. Elevators

   • Pitch control around the lateral axis
   • Both elevators move up and down at the same time
   • Up deflected elevators create nose up motion
   • Down deflected elevators create a nose down motion

3. Rudder

   • Controls yaw around the vertical (normal) axis
   • Left deflect rudder creates nose left motion
   • Right deflect creates nose right motion

4. Elevons and Rudderators

   • Aircraft with a V-tail
   • Combination of rudder and elevator
   • Both surfaces simultaneously moved up or down, provide elevator function
   • One surface up and other down, rudder function
   • Advantages
     • Saves Weight
     • No vertical stabilizer needed
   • Disadvantages
     • Effective elevator area only projected to the horizontal plane
     • Effective rudder surface is only area projected to the vertical plane
       • Ruddervator surface area must be increased
     • Do not have full elevator and rudder deflections available at the same time
     • Control surface adjustment is more complicated because combined inputs
   • Delta Wing
     • Elevons are combination of elevator and aileron
     • Both surfaces up = elevator function
     • One surface up, one down = decreased lift on one wing and icreased on other
       • Aileron function