Y-tail (V-tail with ventral fin) — dimension sheet
Source: Xem Studio, https://xemstudio.com/objects/y-tail/  (sheet CC BY 4.0; files Xem Studio Design License, https://xemstudio.com/license/)
Basis: Design rules and figures from the cited sources; example geometry by Xem Studio
Catalog version: 2026-10-20

Sizes: see table below
- Bhattacharya et al. describe the Y-tail as a V-tail with a rudder added at the rear, which improves yaw stability and has less interference drag than a conventional tail.
- Its performance depends on the V dihedral and the length of the vertical stub (Bhattacharya et al.). The ventral fin takes over pure yaw control, easing the coupled ruddervator problem of a plain V-tail (FAA PHAK ch.6).
- Their maritime UAV design used NACA 2412 for the horizontal elements and NACA 0024 for the vertical, with a 105 cm tail arm on a 165 cm fuselage.
- Used on: LearAvia Lear Fan 2100, MQ-9 Reaper, Waiex.
- 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.

parameter  value or range  source
Example UAV tail arm / fuselage length  105 cm / 165 cm  Bhattacharya et al.
Example vertical tail area  0.1568 m^2 on 0.549 m^2 reference area  Bhattacharya et al.
Example airfoils  NACA 2412 (horizontal), NACA 0024 (vertical)  Bhattacharya et al.
Reference build  V panels as V-tail example plus 80 mm ventral fin  computed

Files elsewhere (not hosted by Xem Studio; license as stated by the publisher):
- engrXiv (Bhattacharya et al., ICMMM 2023): Design and Computational Analysis of Y-tail Configuration for Maritime UAV — web — Publisher's page; dimensions are facts — https://engrxiv.org/preprint/download/6582/10812/9153
- FAA: Pilot's Handbook of Aeronautical Knowledge (FAA-H-8083-25), Ch. 6 Flight Controls — web — Publisher's page; dimensions are facts — https://www.faa.gov/sites/faa.gov/files/08_phak_ch6.pdf

Free files (Xem Studio Design License, Xem Studio; STEP + STL, 1 parts): https://xemstudio.com/files/hardware/y-tail/index.json
API: https://xemstudio.com/api/geometry?object=y-tail