# Tandem-wing ground-effect craft (Jorg type)

> How do tandem-wing ground-effect craft work?

- 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/tandem-wig-configuration/ · JSON: https://xemstudio.com/api/geometry?object=tandem-wig-configuration · Plain text: https://xemstudio.com/objects/tandem-wig-configuration/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

- The Jorg tandem airfoil boat places two wings in ground effect one behind the other; its stability is 'very sensitive' to the combination of pitch angle and ground clearance (Rozhdestvensky).
- The 3-ton SM-1 tandem had a high take-off speed and a narrow range of stable heights (Rozhdestvensky). Ground-effect stability needs the aerodynamic centre in height upstream of the centre in pitch (Irodov criterion, Rozhdestvensky).
- Used on: Jorg TAB, SM-1.
- 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 |
|---|---|---|
| SM-1 weight | 3 t | Rozhdestvensky 2006 |
| Stability | very sensitive to pitch/clearance; narrow stable height range | Rozhdestvensky 2006 |
| Reference build | two 600 x 150 mm wings, endplates 30 | illustrative |

## 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/tandem-wig-configuration/index.json · license: https://xemstudio.com/files/hardware/tandem-wig-configuration/LICENSE.md

- tandem-wig-configuration-wing: [STEP](https://xemstudio.com/files/hardware/tandem-wig-configuration/tandem-wig-configuration-wing.step) · [STL](https://xemstudio.com/files/hardware/tandem-wig-configuration/tandem-wig-configuration-wing.stl) — ekranoplan tandem: span 600, chord 150 mm, anhedral 0°, endplates 30 mm (scale to your craft)

## Questions

**Is a tandem WIG easy to stabilise?**

No; Rozhdestvensky calls its stability very sensitive to pitch and clearance.

## 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/)
- [Power-augmented ram (PAR)](https://xemstudio.com/objects/power-augmented-ram-par/)
- [Endplates on ground-effect wings](https://xemstudio.com/objects/wig-endplates/)