Controls

1. Basics

Ailerons:

  • control roll by raising one aileron or the other

  • raise and lower wings

  • raising right + lower left → roll to right

  • raising left + lower right → roll to left

Rudder:

  • control yaw (turning)

  • rudder moves left and right

  • left → yaw to left, right → yaw to right

Elevators:

  • tail section, control pitch (lift, angle of attack)

  • raise and lower

  • lowering → nose goes down, raising → nose goes up

2. Controlling the controls (motor options)

  • two ailerons, one rudder, two elevators is common

  • rudder controls yaw (essential for steering) → plane will start to roll on its own

    • ailerons control roll → without ailerons the pilot will lose control when turning

  • elevators are essential for controlling lift and angle of attack

  • propellers → essential for moving

  • landing?

Common types of motors:

  1. stepper

  • designed for precise positional control & tracking

  • relative positioning → discrete “steps”, tiny margin of error

  • typical: 200 steps per rev, 1.8 deg per step

  • high torque, low speed

  • applications: 3DP, CNC, large robot arms

longruner geared stepper

2. servo

  • designed for precise positioning → angular position of motor shaft (horn)

  • absolute positioning

  • a little more expensive

  • high torque

  • used as joints (robotic arms & legs) and steering for RC cars

  • ailerons, rudder, elevators

KeeYees PCA9685 Raspberry Helicopter Airplane

3. brushless

  • controllable speed

  • greater reliability, faster max speed, better efficiency than brushed DC (but more expensive)

  • not THAT expensive

  • high power output for small motor

  • propellers, camera gimbals

Brushless Motor DX2205-2300KV Racing

KV1000 Brushless Aircraft Multicopter Quadcopter

Motors Plan:

  • control both elevators with one servo

  • control both ailerons with one servo → blue mechanism:

  • minimum: 3 servos for controls

3. Control Mechanisms

  • planes have controls in fuselage, move ailerons with control rods

  • Linkages!!

Single servo aileron control:

https://www.youtube.com/watch?v=G2z-r5WeHHI&ab_channel=ValterVidaLealValterVidaLeal

More sophisticated version (for commercial planes):

 

Single servo elevator control:

https://www.youtube.com/watch?v=f8l_fzUYXMY&ab_channel=JeffersonMartinsAraujo

Flap control linkage:

https://www.youtube.com/watch?v=U3AHgk0SUoI&ab_channel=JeffersonMartinsAraujoJeffersonMartinsAraujo

  • good to keep servo → flap angular movement 1:1

  • keep control horn right above flap hinge → symmetrical response

  • keep control horn and servo vertical at neutral position → symmetrical response

Flap attachment:

  • commercial: mostly hinges + brackets

  • some hobbyists stick the wires straight into the ailerons from the wings (probably very flimsy)

  • sometimes just connected with a few hinges (also hobbyists)

  • lots of options

 

Ref:

https://www.grc.nasa.gov/www/k-12/UEET/StudentSite/dynamicsofflight.html

https://maker.pro/custom/tutorial/what-type-of-motor-is-best-for-my-project

https://www.instructables.com/Beginners-Guide-to-Connecting-Your-RC-Plane-Electr/

https://www.aopa.org/news-and-media/all-news/2019/september/flight-training-magazine/how-it-works-ailerons