# Flying wing / tailless aircraft

> How does a flying wing stay stable without a tail?

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

- A tailless aircraft provides pitch stability from the wing itself: on a swept wing, washout on the outer panel lets the tips act like a tail, matching tip and root angle of attack at the design condition (R/C Soaring Digest).
- NASA's Prandtl-D wings use Prandtl's 1933 bell-shaped lift distribution, which for a wing of constrained mass gives 11% less induced drag with 22% more span than the elliptical optimum, plus tip upwash and proverse yaw that let it fly without a fin (NASA Armstrong).
- Ground-effect reviews note flying-wing WIG craft have a small stable height-pitch range (Rozhdestvensky). Elevons replace elevators and ailerons (Heritage Concorde).
- Used on: NASA Prandtl-D, Concorde (tailless delta).
- 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 |
|---|---|---|
| Bell vs elliptical (constrained mass) | 11% less induced drag, 22% more span | NASA Armstrong (Newton) |
| Prandtl-1/-2 span; Prandtl-3 span | 12.3 ft; 25 ft | NASA Armstrong |
| Washout range on wings generally | 0-10 deg nose-down | ERAU (Leishman) |
| Reference build | span 1000, root 250, tip 120, LE sweep 25 deg, washout via twist | illustrative |

## Where the files are

- R/C Soaring Digest: [Twist Distributions for Swept Wings, Part 2 (June 2002)](https://new.rcsoaringdigest.com/2002/06/twist-distributions-for-swept-wings/[pdf].pdf) — web — Publisher's page; dimensions are facts
- NASA Armstrong / UC Berkeley (L. Newton): [Stability and Control Derivative Estimation for the Bell-Shaped Lift Distribution](https://ntrs.nasa.gov/api/citations/20180002374/downloads/20180002374.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
- Progress in Aerospace Sciences (K.V. Rozhdestvensky, 2006): [Wing-in-ground effect vehicles (review)](https://www.hassanhameed.com/wp-content/uploads/2016/01/wingingroundeffectvehicles-130120003005-phpapp01.pdf) — web — Publisher's page; dimensions are facts
- Heritage Concorde: [The Wing](https://www.heritageconcorde.com/the-wing) — web — Publisher's page; dimensions are facts

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

Index: https://xemstudio.com/files/hardware/flying-wing-tailless/index.json · license: https://xemstudio.com/files/hardware/flying-wing-tailless/LICENSE.md

- flying-wing-tailless-wing: [STEP](https://xemstudio.com/files/hardware/flying-wing-tailless/flying-wing-tailless-wing.step) · [STL](https://xemstudio.com/files/hardware/flying-wing-tailless/flying-wing-tailless-wing.stl) — swept planform: span 1000, root 250, tip 120 mm, LE sweep 25°, dihedral 0°, NACA 0012

## Questions

**How much washout does a flying wing need?**

Enough that the outer panel balances the wing in pitch at the design lift coefficient (R/C Soaring Digest); Leishman gives 0-10 deg as the usual range for wings in general.

## Fits with

- [Tail volume coefficient (horizontal and vertical tail sizing)](https://xemstudio.com/objects/tail-volume-coefficient/)
- [Tail moment arm (tail lever arm ratios)](https://xemstudio.com/objects/tail-moment-arm/)
- [Conventional tail (low-mounted stabiliser and single fin)](https://xemstudio.com/objects/conventional-tail/)
- [T-tail (stabiliser on top of the fin)](https://xemstudio.com/objects/t-tail/)
- [Cruciform tail (stabiliser part-way up the fin)](https://xemstudio.com/objects/cruciform-tail/)
- [V-tail (butterfly tail with ruddervators)](https://xemstudio.com/objects/v-tail/)