Tail volume coefficient (horizontal and vertical tail sizing) — dimension sheet Source: Xem Studio, https://xemstudio.com/objects/tail-volume-coefficient/ (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 - The tail volume coefficient multiplies tail area by tail arm and divides by wing area times a reference length (MAC for the stabiliser, span for the fin), so one number captures how much pitch or yaw 'leverage' the tail has (EAA Chapter 62, Kitplanes). - Designers pick a coefficient from aircraft of the same class and solve for tail area or arm; published class values run from 0.50/0.02 for sailplanes to 1.00/0.09 for jet transports (HAW Hamburg Table 2.1, matching Raymer's Table 6.4 values quoted by OpenConcept). - A longer arm needs less area for the same coefficient, and the ratio of tail arm to MAC sets how much tail lift is needed to trim the wing (Kitplanes, Wainfan). Light aircraft with little c.g. travel, like the J-3 Cub, sit at the low end (Vh 0.34) while four-seaters with more c.g. travel, like the Navion, sit high (Vh 0.69) (EAA62/Pazmany). - Used on: Piper J-3 Cub, Luscombe Silvaire, Ryan Navion. - 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 Horizontal tail volume Vh = (Sh x Lh)/(Sw x MAC) definition EAA62 / Kitplanes Vertical tail volume Vv = (Sv x Lv)/(Sw x b) definition EAA62 Sailplane Vh / Vv 0.50 / 0.02 HAW Hamburg Table 2.1 (Raymer-type table) Homebuilt Vh / Vv 0.50 / 0.04 HAW Hamburg Table 2.1 General aviation single engine Vh / Vv 0.70 / 0.04 HAW Hamburg Table 2.1 General aviation twin engine Vh / Vv 0.80 / 0.07 HAW Hamburg Table 2.1 Agricultural Vh / Vv 0.50 / 0.04 HAW Hamburg Table 2.1 Twin turboprop Vh / Vv 0.90 / 0.08 HAW Hamburg Table 2.1; OpenConcept (Raymer 1992 Table 6.4) Flying boat Vh / Vv 0.70 / 0.06 HAW Hamburg Table 2.1 Jet trainer Vh / Vv 0.70 / 0.06 HAW Hamburg Table 2.1 Jet fighter Vh / Vv 0.40 / 0.07 HAW Hamburg Table 2.1 Military cargo/bomber Vh / Vv 1.00 / 0.08 HAW Hamburg Table 2.1 Jet transport Vh / Vv 1.00 / 0.09 HAW Hamburg Table 2.1; OpenConcept (Raymer 1992 Table 6.4) Typical ranges (statistics) Vh 0.5-1.0; Vv 0.03-0.08 Scholz 2021 Piper J-3 Cub Vh / Vv 0.340 / 0.022 EAA62 (Pazmany) Luscombe Silvaire Vh / Vv 0.442 / 0.026 EAA62 (Pazmany) Ryan Navion Vh / Vv 0.692 / 0.040 EAA62 (Pazmany) T-tail allowance tail volume coefficients may be reduced by 4% Scholz 2021 Reference build (computed) wing 1000 x 200 mm, Lh 500 mm, Vh 0.50 -> Sh 40,000 mm^2; Vv 0.04 -> Sv 16,000 mm^2 computed from table above Files elsewhere (not hosted by Xem Studio; license as stated by the publisher): - EAA Chapter 62 (Stan Hall, from Pazmany 'Light Airplane Design'): How Big The Tail — web — Publisher's page; dimensions are facts — https://eaa62.org/technotes/tail.htm - HAW Hamburg (Aircraft Design and Systems Group): Empennage sizing: tail lever arm as % of fuselage length (thesis; Table 2.1 typical tail volume coefficients) — web — Publisher's page; dimensions are facts — https://www.fzt.haw-hamburg.de/pers/Scholz/arbeiten/TextMcDavid.pdf - MDO Lab, University of Michigan (OpenConcept docs): Tail volume coefficient sizing (Raymer 1992 Table 6.4 defaults) — web — Publisher's page; dimensions are facts — https://mdolab-openconcept.readthedocs-hosted.com/en/latest/_srcdocs/packages/stability/tail_volume_coefficient_sizing.html - INCAS Bulletin / HAW Hamburg (D. Scholz): Empennage sizing with the tail volume complemented with a method for dorsal fin layout (2021) — web — Publisher's page; dimensions are facts — https://www.fzt.haw-hamburg.de/pers/Scholz/Aero/AERO_PUB_INCAS_TailVolume_Vol13No3_2021.pdf - Kitplanes (B. Wainfan): Design Process: Horizontal Tail (2022) — web — Publisher's page; dimensions are facts — https://www.kitplanes.com/?p=177046 Free files (Xem Studio Design License, Xem Studio; STEP + STL, 1 parts): https://xemstudio.com/files/hardware/tail-volume-coefficient/index.json API: https://xemstudio.com/api/geometry?object=tail-volume-coefficient