1 — One Control per Axis
Lesson 6 set up the three axes through the centre of gravity. The primary flight controls are simply the three surfaces that rotate the aeroplane about those axes — one each:
The control column moves the elevator on the tailplane. Pull back → elevator up → the tail is pushed down → the nose pitches up about the lateral axis. The elevator controls angle of attack, and so airspeed.
The control column moves the ailerons differentially — one down, one up. The wing with the down-going aileron makes more lift and rises, so the aircraft rolls about the longitudinal axis. Ailerons bank the aircraft into and out of turns.
The rudder pedals move the rudder on the fin. Right pedal → rudder deflects right → the tail is pushed left → the nose yaws right about the normal axis. The rudder coordinates the turn; it does not steer it.
- Elevator (on the tailplane) → pitch about the lateral axis.
- Ailerons (at the wingtips) → roll about the longitudinal axis.
- Rudder (on the fin) → yaw about the normal axis.
Notice each control acts at the end of a long arm from the CG — the tail and the wingtips — so a small surface gives a large moment.
2 — How a Control Surface Works
Every control surface is a small, movable aerofoil. Deflecting it changes the camber of the surface it is part of, which changes that surface’s lift, which makes a moment about the axis:
- Pull back → the elevator rises → the tailplane makes a stronger downward force → the tail goes down and the nose comes up.
- Move the stick right → the right aileron rises and the left lowers → the left wing makes more lift and rises → the aeroplane rolls right.
- Press the right pedal → the rudder deflects right → the fin is pushed left → the nose yaws right.
½ρV²). At low speed the controls feel soft and
sloppy and need larger deflections; at high speed they are firm and powerful. This is the same
½ρV² from the lift lessons, felt through the stick.3 — Adverse Yaw
Roll is the control with a sting in the tail. When you roll, the down-going aileron raises its wing by making more lift — but more lift comes with more induced drag (Lesson 3). The up-going aileron does the opposite: less lift, less drag. So the rising (outer) wing is also the higher-drag wing, and that drag yaws the nose away from the turn:
Rolling left, the down-going aileron on the right wing makes more lift to raise that wing — but also more induced drag. The up-going aileron on the left wing makes less lift and less drag. The extra drag on the outer (rising) wing yaws the nose right, away from the intended left turn — adverse yaw. Cures: lead with rudder, plus design fixes — differential ailerons (the up aileron moves more than the down) and Frise ailerons (the up aileron projects into the airflow to add balancing drag).
This is adverse yaw: roll left and, left to itself, the nose initially swings right. It is worst at low speed and high angle of attack, where induced drag is largest — slow flight, the climb, the turn onto final.
4 — Secondary Effects and Coordination
Because the controls share the same airflow, each has a secondary effect about another axis: rudder also rolls the aeroplane (the leading wing speeds up and makes more lift), and aileron drag yaws it. That coupling is exactly why a good turn uses all three controls together — aileron to set and hold the bank, rudder to balance the yaw, and elevator to hold the nose where the extra lift is needed. We measure the result with the slip/skid ball: kept centred, the turn is coordinated.
5 — Why This Matters to the Pilot
Coordinated use of the controls is the core motor skill of flying, examined throughout your training. Adverse yaw is why your instructor says “a little rudder with that aileron,” and why an uncoordinated, slow, climbing turn — aileron without rudder — is a recognised path toward a stall/spin (Lesson 4). The aerodynamics here is the why behind “stick and rudder.”
The control feel and effects described are typical of a light single; your aircraft’s specific handling and any limitations come from its POH/AFM.
