# Differential ailerons

> What are differential ailerons?

- Category: Aircraft design › Control surfaces
- Kind: Standard part
- Basis: Design rules and figures from the cited sources; example geometry by Xem Studio
- Page: https://xemstudio.com/objects/differential-ailerons/ · JSON: https://xemstudio.com/api/geometry?object=differential-ailerons · Plain text: https://xemstudio.com/objects/differential-ailerons/sheet.txt
- License: dimension sheet CC BY 4.0 (Xem Studio); files Xem Studio Design License (free to use and sell from, not to redistribute as files: https://xemstudio.com/license/)
- Use in every chat: add https://xemstudio.com/mcp as a connector (https://xemstudio.com/use-with-ai/)

**Exact dimensions.** True size, with no printing tolerance added.

## Notes

- Differential ailerons deflect the up-going aileron farther than the down-going one, adding drag on the descending wing; adverse yaw is reduced but not eliminated (FAA PHAK ch.6).
- Sadraey notes Piper aircraft generally use differential ailerons; a Cessna 182's 20 up / 14 down and a 777's 30 up / 10 down show the asymmetry (Sadraey Table 12.1).
- Used on: Cessna 182, Boeing 777-200, Piper aircraft (generally).
- The file is a reference example built by Xem Studio from the numbers above. Sizes the sources do not fix are illustrative; scale the example to your own vehicle.

## Sizes

| parameter | value or range | source |
|---|---|---|
| Cessna 182 up/down | 20 / 14 deg | Sadraey Table 12.1 |
| Boeing 777-200 up/down | 30 / 10 deg | Sadraey Table 12.1 |
| Air Tractor AT-802 up/down | 17 / 13 deg | Sadraey Table 12.1 |
| Reference build | chord 200, 20% aileron, 20 deg up | Cessna 182 ratio |

## Where the files are

- FAA: [Pilot's Handbook of Aeronautical Knowledge (FAA-H-8083-25), Ch. 6 Flight Controls](https://www.faa.gov/sites/faa.gov/files/08_phak_ch6.pdf) — web — Publisher's page; dimensions are facts
- Universidad de Sevilla course files (Sadraey, Aircraft Design, Ch. 12): [Design of Control Surfaces (Aileron)](https://aero.us.es/adesign/Slides/Extra/Stability/Design_Control_Surface/Chapter%2012.%20Desig%20of%20Control%20Surfaces%20%28Aileron%29.pdf) — web — Publisher's page; dimensions are facts

## Free STEP/STL (1 parts, Xem Studio Design License, Xem Studio)

Index: https://xemstudio.com/files/hardware/differential-ailerons/index.json · license: https://xemstudio.com/files/hardware/differential-ailerons/LICENSE.md

- differential-ailerons-wing-segment: [STEP](https://xemstudio.com/files/hardware/differential-ailerons/differential-ailerons-wing-segment.step) · [STL](https://xemstudio.com/files/hardware/differential-ailerons/differential-ailerons-wing-segment.stl) — aileron: wing segment 200 mm chord × 300 mm, 20 % chord surface deflected 20°

## Questions

**How much differential?**

Full-size examples range from 20/14 deg (Cessna 182) to 30/10 deg (777) (Sadraey Table 12.1).

## Fits with

- [Aileron](https://xemstudio.com/objects/aileron/)
- [Frise aileron](https://xemstudio.com/objects/frise-aileron/)
- [Elevon](https://xemstudio.com/objects/elevon/)
- [Flaperon](https://xemstudio.com/objects/flaperon/)
- [Spoiler](https://xemstudio.com/objects/spoiler/)
- [Trim tab and antiservo tab](https://xemstudio.com/objects/trim-tab/)