# Conventional tail (low-mounted stabiliser and single fin)

> What is a conventional aircraft tail and why is it the default?

- Category: Aircraft design › Tail configurations
- Kind: Standard part
- Basis: Design rules and figures from the cited sources; example geometry by Xem Studio
- Page: https://xemstudio.com/objects/conventional-tail/ · JSON: https://xemstudio.com/api/geometry?object=conventional-tail · Plain text: https://xemstudio.com/objects/conventional-tail/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 conventional tail mounts the horizontal stabiliser low on the fuselage with a single fin above it; Arnedo calls it structurally compact and aerodynamically efficient, the standard for aircraft with under-wing engines.
- It is easy and cheap to build and hard to stall, but it sits in the wing's downwash and the propeller slipstream (Bhattacharya et al.; Kitplanes). On single-engine tractor aircraft the slipstream over a low tail helps raise the nosewheel, which a T-tail loses (Kitplanes T-Tails).
- Size it with the tail volume coefficient: Raymer-type tables give Vh 0.50/Vv 0.04 for homebuilts and 0.70/0.04 for GA singles (HAW Hamburg Table 2.1).
- Used on: Cessna 172, Beechcraft A36 Bonanza, Boeing 777, Airbus A320, Piper Cherokee Six (PA-32).
- 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 |
|---|---|---|
| Homebuilt Vh / Vv | 0.50 / 0.04 | HAW Hamburg Table 2.1 |
| GA single Vh / Vv | 0.70 / 0.04 | HAW Hamburg Table 2.1 |
| Horizontal vs vertical tail arm | horizontal about 5% longer | Scholz 2021 |
| Piper J-3 Sh/Sw, Sv/Sw | 13.7%, 5.7% | EAA62 (Pazmany) |
| Reference build | Sh 40,000 mm^2 (400 x 100), Sv 16,000 mm^2 (140 x 114), arm 500 mm on a 1000 x 200 mm wing | computed (Vh 0.50, Vv 0.04) |

## Where the files are

- LibreTexts (Arnedo, Fundamentals of Aerospace Engineering): [2.2.3 Empennage](https://eng.libretexts.org/Bookshelves/Aerospace_Engineering/Fundamentals_of_Aerospace_Engineering_(Arnedo)/02%3A_Generalities/2.02%3A_Parts_of_the_aircraft/2.2.03%3A_Empennage) — web — Publisher's page; dimensions are facts
- engrXiv (Bhattacharya et al., ICMMM 2023): [Design and Computational Analysis of Y-tail Configuration for Maritime UAV](https://engrxiv.org/preprint/download/6582/10812/9153) — web — Publisher's page; dimensions are facts
- Kitplanes (B. Wainfan): [Design Process: T-Tails (2022)](https://www.kitplanes.com/design-process-t-tails/) — web — Publisher's page; dimensions are facts
- HAW Hamburg (Aircraft Design and Systems Group): [Empennage sizing: tail lever arm as % of fuselage length (thesis; Table 2.1 typical tail volume coefficients)](https://www.fzt.haw-hamburg.de/pers/Scholz/arbeiten/TextMcDavid.pdf) — web — Publisher's page; dimensions are facts
- INCAS Bulletin / HAW Hamburg (D. Scholz): [Empennage sizing with the tail volume complemented with a method for dorsal fin layout (2021)](https://www.fzt.haw-hamburg.de/pers/Scholz/Aero/AERO_PUB_INCAS_TailVolume_Vol13No3_2021.pdf) — web — Publisher's page; dimensions are facts
- EAA Chapter 62 (Stan Hall, from Pazmany 'Light Airplane Design'): [How Big The Tail](https://eaa62.org/technotes/tail.htm) — web — Publisher's page; dimensions are facts

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

Index: https://xemstudio.com/files/hardware/conventional-tail/index.json · license: https://xemstudio.com/files/hardware/conventional-tail/LICENSE.md

- conventional-tail-tail: [STEP](https://xemstudio.com/files/hardware/conventional-tail/conventional-tail-tail.step) · [STL](https://xemstudio.com/files/hardware/conventional-tail/conventional-tail-tail.stl) — conventional layout: horizontal span 400 × chord 100, vertical 140 × 114 mm on a 500 mm boom, NACA 0009 surfaces

## Questions

**Is a conventional tail better than a T-tail?**

It is lighter and avoids T-tail deep stall, but it sits in wing downwash and propwash (Arnedo; Kitplanes T-Tails).

## Fits with

- [Tail volume coefficient (horizontal and vertical tail sizing)](https://xemstudio.com/objects/tail-volume-coefficient/)
- [Tail moment arm (tail lever arm ratios)](https://xemstudio.com/objects/tail-moment-arm/)
- [T-tail (stabiliser on top of the fin)](https://xemstudio.com/objects/t-tail/)
- [Cruciform tail (stabiliser part-way up the fin)](https://xemstudio.com/objects/cruciform-tail/)
- [V-tail (butterfly tail with ruddervators)](https://xemstudio.com/objects/v-tail/)
- [Inverted V-tail (anhedral V)](https://xemstudio.com/objects/inverted-v-tail/)