# Lippisch reverse-delta ground-effect craft

> Why does the Lippisch WIG use a reverse delta wing?

- Category: Aircraft design › Ground-effect design
- Kind: Standard part
- Basis: Design rules and figures from the cited sources; example geometry by Xem Studio
- Page: https://xemstudio.com/objects/lippisch-reverse-delta-wig/ · JSON: https://xemstudio.com/api/geometry?object=lippisch-reverse-delta-wig · Plain text: https://xemstudio.com/objects/lippisch-reverse-delta-wig/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

- Lippisch's planform has chord decreasing linearly from root to tip, which limits the longitudinal shift of the centre of pressure with height, combined with moderate AR above 3, inverse dihedral to hold the hull above water, and a large high tailplane (Rozhdestvensky).
- The X-113 reached L/D around 25 (Rozhdestvensky). Experiments show the reverse delta has delayed stall and higher L/D than a regular delta, and in ground effect its tip-vortex circulation rose 65% (Frontiers 2022 review).
- Effective in-ground-effect height for reverse deltas is given as below about 40-45% of chord, and 15 deg anhedral was selected in one study (Frontiers 2022).
- Used on: Lippisch X-113, Lippisch X-114, Airfish-3.
- 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 |
|---|---|---|
| X-113 L/D | about 25 | Rozhdestvensky 2006 |
| X-114 weight | 1.35 t | Rozhdestvensky 2006 |
| Lippisch AR | above 3 | Rozhdestvensky 2006 |
| Selected anhedral (study) | 15 deg | Frontiers 2022 |
| Effective height | < 40-45% chord | Frontiers 2022 |
| Reverse delta CLmax | 1.175 at 38 deg | Frontiers 2022 |
| Reference build | span 700, root 400 (AR 3.5), anhedral 15 deg, endplates 40 | 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/lippisch-reverse-delta-wig/index.json · license: https://xemstudio.com/files/hardware/lippisch-reverse-delta-wig/LICENSE.md

- lippisch-reverse-delta-wig-wing: [STEP](https://xemstudio.com/files/hardware/lippisch-reverse-delta-wig/lippisch-reverse-delta-wig-wing.step) · [STL](https://xemstudio.com/files/hardware/lippisch-reverse-delta-wig/lippisch-reverse-delta-wig-wing.stl) — Lippisch reverse delta: straight leading edge, trailing edge swept forward to the tips, span 700, root 400 mm, anhedral 15°, endplates 40 mm (scale to your craft)

## Questions

**Why reverse delta for WIG?**

It keeps the centre of pressure from moving much as height changes, easing pitch stability (Rozhdestvensky).

## Fits with

- [Ground effect: height/span ratio and induced-drag reduction](https://xemstudio.com/objects/ground-effect-height-span-ratio/)
- [Ground effect: height/chord ratio (ram / chord-dominated regime)](https://xemstudio.com/objects/ground-effect-height-chord-ratio/)
- [Ekranoplan layout (low wing + high tailplane out of ground effect)](https://xemstudio.com/objects/ekranoplan-wing-tail-layout/)
- [Tandem-wing ground-effect craft (Jorg type)](https://xemstudio.com/objects/tandem-wig-configuration/)
- [Power-augmented ram (PAR)](https://xemstudio.com/objects/power-augmented-ram-par/)
- [Endplates on ground-effect wings](https://xemstudio.com/objects/wig-endplates/)