# Alexeyev SM-8 ekranoplan (second 1/4-scale KM test craft)

> What are the dimensions of the Alexeyev SM-8 ekranoplan?

- Category: Ground-effect craft › Soviet experimental and scale prototypes
- Kind: Modern device
- Basis: Secondary source: Old Machine Press (copy of the maker's figures; the maker publishes none directly)
- Page: https://xemstudio.com/objects/alexeyev-sm-8-ekranoplan/ · JSON: https://xemstudio.com/api/geometry?object=alexeyev-sm-8-ekranoplan · Plain text: https://xemstudio.com/objects/alexeyev-sm-8-ekranoplan/sheet.txt
- License: dimension sheet CC BY 4.0 (Xem Studio); files CC BY 4.0 or their publisher's license
- Use in every chat: add https://xemstudio.com/mcp as a connector (https://xemstudio.com/use-with-ai/)

## Overall (mm)

| length | width | height |
|---|---|---|
| 18500 | 9500 | 5500 |

**Exact dimensions.** True size, with no printing tolerance added.

## Notes

- The SM-8 replaced the SM-5 as the quarter-scale KM trainer and test craft.
- The file is an 18.5 × 9.5 × 5.5 m box. The source's weight figures conflict (16,094 lb is about 7,300 kg, not 8,100 kg), so weight is not used.
- Marked secondary.
- True size, no printing tolerance added. Only published numbers are used; anything not published is said so.
- Secondary source: the numbers come from a retailer or magazine copy of the maker's specification.

## Sizes

| dimension | value |
|---|---|
| Length | 18.5 m (60 ft 8 in) |
| Wingspan | 9.5 m (31 ft 2 in) |
| Height | 5.5 m (18 ft 1 in) |
| Maximum weight | published as 16,094 lb / 8,100 kg (the two figures do not agree) |
| Engines | 2 × Mikulin KR7-300 jet engines |
| Ground-effect flying height | 1–3 m (3–10 ft) |

## Where the files are

- Old Machine Press: [Alexeyev KM Ekranoplan – Caspian Sea Monster (SM-8 section)](https://oldmachinepress.com/2019/11/05/alexeyev-km-ekranoplan-caspian-sea-monster/) — web — Publisher's page; dimensions are facts

## Free STEP/STL (1 parts, CC BY 4.0, Xem Studio)

Index: https://xemstudio.com/files/hardware/alexeyev-sm-8-ekranoplan/index.json

- alexeyev-sm-8-ekranoplan-envelope: [STEP](https://xemstudio.com/files/hardware/alexeyev-sm-8-ekranoplan/alexeyev-sm-8-ekranoplan-envelope.step) · [STL](https://xemstudio.com/files/hardware/alexeyev-sm-8-ekranoplan/alexeyev-sm-8-ekranoplan-envelope.stl) — Envelope 18500 × 9500 × 5500 mm (Real craft: overall length × wingspan × overall height as published)

## Questions

**How does the SM-8 differ from the SM-5?**

It is 18.5 m long versus 18.0 m; wingspan (9.5 m), height (5.5 m) and engines (2 × KR7-300) are the same.

## Fits with

- [Alexeyev SM-5 ekranoplan (1/4-scale KM test craft)](https://xemstudio.com/objects/alexeyev-sm-5-ekranoplan/)
- [Bartini Beriev VVA-14 (14M1P ground-effect amphibian)](https://xemstudio.com/objects/bartini-beriev-vva-14/)
- [Grunin ESKA-1 experimental ekranoplan (2-seat)](https://xemstudio.com/objects/grunin-eska-1-ekranoplan/)