# Reverse delta (Lippisch) wing

> What is a reverse delta wing?

- 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/reverse-delta-wing/ · JSON: https://xemstudio.com/api/geometry?object=reverse-delta-wing · Plain text: https://xemstudio.com/objects/reverse-delta-wing/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 reverse delta's chord decreases linearly from root to tip with the point leading, the planform Lippisch used for ground-effect craft because it limits centre-of-pressure shift with height (Rozhdestvensky).
- Compared with a regular delta it has lower CL and CD, a delayed stall and higher L/D, with CLmax 1.175 at 38 deg vs 1.26 at 34 deg for the delta (Frontiers 2022 review).
- Lippisch craft combined it with moderate AR above 3, anhedral and a large high-mounted tailplane (Rozhdestvensky).
- Used on: Lippisch X-113, Lippisch X-114.
- 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 |
|---|---|---|
| Reverse delta CLmax / stall | 1.175 at 38 deg | Frontiers 2022 review |
| Regular delta CLmax / stall | 1.26 at 34 deg | Frontiers 2022 review |
| Lippisch AR | moderate, above 3 | Rozhdestvensky 2006 |
| Reference build | span 700, root 400 (AR 3.5) | computed |

## Where the files are

- 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
- Frontiers in Aerospace Engineering (2022): [Review of ground-effect experiments on rectangular, reverse-delta and delta wings](https://www.frontiersin.org/journals/aerospace-engineering/articles/10.3389/fpace.2022.975158/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/reverse-delta-wing/index.json · license: https://xemstudio.com/files/hardware/reverse-delta-wing/LICENSE.md

- reverse-delta-wing-wing: [STEP](https://xemstudio.com/files/hardware/reverse-delta-wing/reverse-delta-wing-wing.step) · [STL](https://xemstudio.com/files/hardware/reverse-delta-wing/reverse-delta-wing-wing.stl) — reverse delta planform: span 700, root 400, tip 0 mm, LE sweep -30°, dihedral 0°, NACA 0012

## Questions

**Why do ground-effect craft use reverse deltas?**

The planform keeps the centre of pressure from moving much as height changes (Rozhdestvensky).

## Fits with

- [Rectangular (constant-chord) wing](https://xemstudio.com/objects/rectangular-wing/)
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- [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/)