# WIG hulls: steps, hydrofoils and hydroskis

> How do WIG craft get off the water?

- 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/wig-hull-steps-hydrofoils/ · JSON: https://xemstudio.com/api/geometry?object=wig-hull-steps-hydrofoils · Plain text: https://xemstudio.com/objects/wig-hull-steps-hydrofoils/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

- WIG craft must break free of water drag before flying. Designs used hull steps (m-Sky 2), front and stern hydrofoils to soften water landing (Lippisch X-114), bow hydroskis for pitch stability (Lockheed 1963) and aft ski structures to trim take-off and landing (Douglas DAW-S) (Rozhdestvensky).
- Weiland proposed hydroskis as an alternative to power augmentation, and the Hoverwing HW20 used a static air cushion with retractable skirts only for take-off (Rozhdestvensky). KM operated in waves up to 3 m at take-off (Rozhdestvensky).
- Used on: Lippisch X-114, m-Sky 2, Douglas DAW-S, Hoverwing HW20.
- 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 |
|---|---|---|
| Lippisch X-114 | two front hydrofoils + one stern | Rozhdestvensky 2006 |
| Lockheed wingship study | V-shaped landing hydrofoil, 4.64 m span | Rozhdestvensky 2006 |
| m-Sky 2 | step on centre-body bottom | Rozhdestvensky 2006 |
| KM take-off wave height | up to 3 m | Rozhdestvensky 2006 |
| Hoverwing HW20 | static cushion, retractable skirts for take-off | Rozhdestvensky 2006 |

## 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

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

Index: https://xemstudio.com/files/hardware/wig-hull-steps-hydrofoils/index.json · license: https://xemstudio.com/files/hardware/wig-hull-steps-hydrofoils/LICENSE.md

- wig-hull-steps-hydrofoils-hull: [STEP](https://xemstudio.com/files/hardware/wig-hull-steps-hydrofoils/wig-hull-steps-hydrofoils-hull.step) · [STL](https://xemstudio.com/files/hardware/wig-hull-steps-hydrofoils/wig-hull-steps-hydrofoils-hull.stl) — stepped hull, 600 × 150 mm, deadrise 20°, 1 steps (sections illustrative, scale to your boat)

## Questions

**What hull helps a WIG model unstick?**

A stepped hull or hydrofoils/hydroskis, all used on full-size craft (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/)
- [Lippisch reverse-delta ground-effect craft](https://xemstudio.com/objects/lippisch-reverse-delta-wig/)
- [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/)