# Aspect ratio

> What aspect ratio should a glider vs a trainer have?

- Category: Aircraft design › Wing planforms
- Kind: Standard part
- Basis: Design rules and figures from the cited sources; example geometry by Xem Studio
- Page: https://xemstudio.com/objects/aspect-ratio/ · JSON: https://xemstudio.com/api/geometry?object=aspect-ratio · Plain text: https://xemstudio.com/objects/aspect-ratio/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

- Aspect ratio is span squared over area (span/chord for a rectangular wing); high AR lowers induced drag and improves glide, since CDi = CL^2/(pi AR e) (NASA Glenn; TU Delft).
- Leishman gives typical AR of 5-10 for small GA aircraft, 9-15 for transports and 30+ for sailplanes; the DG-800 at just over 27 exceeds L/D 50, and Rutan's Voyager used AR 34 (ERAU).
- RC sailplanes are lower: Drela's 3 m Bubble Dancer has 120 in span on 1000 in^2 (AR 14.4, derived) (CRRC).
- Used on: DG-800, Rutan Voyager, Supermarine Spitfire, Bubble Dancer (RC sailplane).
- 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 |
|---|---|---|
| Small GA aircraft AR | 5-10 | ERAU (Leishman) |
| Commercial transport AR | 9-15 | ERAU |
| Sailplane AR | 30 and above | ERAU |
| DG-800 AR / L/D | just over 27 / > 50 | ERAU |
| Rutan Voyager AR | 34 | ERAU |
| Spitfire AR | 5.67 | ERAU |
| Bubble Dancer (RC RES) | 120 in span, 1000 in^2 (AR 14.4 derived) | CRRC |
| Reference build | AR 12 (1200 x 100 mm) | illustrative |

## Where the files are

- NASA Glenn Research Center: [Beginner's Guide to Aeronautics: Wing Geometry](https://www1.grc.nasa.gov/beginners-guide-to-aeronautics/wing-geometry) — web — Publisher's page; dimensions are facts
- TU Delft OpenCourseWare: [AE1101 Introduction to Aerospace Engineering, Aerodynamics 6](https://ocw.tudelft.nl/wp-content/uploads/AE1101-Aero-6.pdf) — web — Publisher's page; dimensions are facts
- Embry-Riddle (Leishman), Introduction to Aerospace Flight Vehicles: [Wing Shapes and Nomenclature](https://eaglepubs.erau.edu/introductiontoaerospaceflightvehicles/chapter/wing-shapes-and-nomenclature/) — web — Publisher's page; dimensions are facts
- Charles River Radio Controllers (M. Drela designs): [Bubble Dancer 3m RES sailplane](https://charlesriverrc.org/articles/on-line-plans/mark-drela-designs/bubble-dancer/) — web — Publisher's page; dimensions are facts

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

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

- aspect-ratio-wing: [STEP](https://xemstudio.com/files/hardware/aspect-ratio/aspect-ratio-wing.step) · [STL](https://xemstudio.com/files/hardware/aspect-ratio/aspect-ratio-wing.stl) — rectangular planform: span 1200, root 100, tip 100 mm, LE sweep 0°, dihedral 3°, NACA 2412

## Questions

**Why do gliders have long thin wings?**

High aspect ratio cuts induced drag: CDi = CL^2/(pi AR e) (TU Delft).

## Fits with

- [Rectangular (constant-chord) wing](https://xemstudio.com/objects/rectangular-wing/)
- [Tapered wing (taper ratio for minimum induced drag)](https://xemstudio.com/objects/tapered-wing/)
- [Elliptical wing](https://xemstudio.com/objects/elliptical-wing/)
- [Swept-back wing](https://xemstudio.com/objects/swept-wing/)
- [Forward-swept wing](https://xemstudio.com/objects/forward-swept-wing/)
- [Delta wing](https://xemstudio.com/objects/delta-wing/)