# Roll Control (Ailerons)

> Mechanism of roll control, adverse yaw, and differential ailerons.

- **Subject:** 081 — Principles of Flight
- **Section:** 081-05 — Control
- **Topic code:** 081-05-04
- **Last reviewed:** 2026-04-01
- **Author:** Pablo Asensio Martínez
- **HTML version:** https://pilotsyllabus.com/en/principles-of-flight/control/roll-lateral-control/

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## Mechanism
Ailerons work by changing the camber of the outer wing section.
*   **Stick Left**: Left aileron UP (decreases lift) -> Left wing drops. Right aileron DOWN (increases lift) -> Right wing rises.

## Adverse Yaw
When banking (e.g., to the left):
*   The **Right Wing** (Up-going) produces **More Lift** -> Therefore produces **More Induced Drag**.
*   The **Left Wing** (Down-going) produces **Less Lift** -> Less Induced Drag.
*   Difference in drag yaws the nose to the **Right** (Opposite to the turn).

## Solutions
1.  **Differential Ailerons**: The up-going aileron travels further up than the down-going travels down. Reduces drag on the up-going wing (less projection) and increases drag on the down-going wing (more projection).
2.  **Frise Ailerons**: The leading edge of the Up-going aileron protrudes below the wing surface, creating parasite drag to counteract the induced drag of the other wing.
3.  **Roll Spoilers**: Spoilers on the down-going wing extend to kill lift AND add drag (yawing IN to the turn).

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Free study notes from pilotsyllabus.com. Not a substitute for training at an approved ATO.