# Twin-boom tail

> What is a twin-boom tail and when is it used?

- 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/twin-boom-tail/ · JSON: https://xemstudio.com/api/geometry?object=twin-boom-tail · Plain text: https://xemstudio.com/objects/twin-boom-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 twin-boom layout carries the tail on two booms instead of a fuselage, usually with an H-tail joining them; Bhattacharya et al. note the added weight of twin booms and propwash drag on the tail.
- The FAA notes pusher propellers suffer more damage than tractors because of lower ground clearance (FAA Powerplant Handbook), and booms leave the space behind a central nacelle open for one.
- The P-38 is the classic example; NASM describes it as a 'twin-tail boom and twin-engine fighter'.
- Used on: Lockheed P-38 Lightning.
- 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 |
|---|---|---|
| Tail sizing | tail volume as conventional (Vh 0.50 / Vv 0.04 homebuilt) | HAW Hamburg Table 2.1 |
| Reference build | boom length 500 mm, H-tail Sh 40,000 mm^2 | computed |

## Where the files are

- Smithsonian National Air and Space Museum: [Lockheed P-38J-10-LO Lightning](https://www.si.edu/object/nasm_A19600295000) — 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
- FAA: [Aviation Maintenance Technician Handbook - Powerplant, Ch. 7 Propellers](https://www.faa.gov/sites/faa.gov/files/09_amtp_ch7.pdf) — 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

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

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

- twin-boom-tail-tail: [STEP](https://xemstudio.com/files/hardware/twin-boom-tail/twin-boom-tail-tail.step) · [STL](https://xemstudio.com/files/hardware/twin-boom-tail/twin-boom-tail-tail.stl) — twin boom layout: horizontal span 400 × chord 100, vertical 100 × 80 mm on a 500 mm boom, NACA 0009 surfaces

## Questions

**Why use twin booms on a pusher RC plane?**

The booms carry the tail around the space behind the pod where a pusher prop turns; pushers are prone to ground strikes (FAA Powerplant Handbook).

## 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/)
- [Conventional tail (low-mounted stabiliser and single fin)](https://xemstudio.com/objects/conventional-tail/)
- [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/)