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Gurney flap

Name: Gurney flap dimension sheet
Creator: Xem Studio
License: https://creativecommons.org/licenses/by/4.0/

What is a Gurney flap? · Standard part · basis: Design rules and figures from the cited sources; example geometry by Xem Studio

Also called: wickerbill, gurney flap height, gurney tab, trailing edge strip, gurney flap rc, gurney flap lift increase, liebeck flap, lift tab

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

sizes: 5 in table

Notes

A Gurney flap is a small strip perpendicular to the trailing edge on the pressure side. Liebeck's 1978 tests used about 1.25% chord and found significant lift and drag improvement, but expected drag penalties above that height (NASA TM-4071).
On the S1223 high-lift airfoil a 1% chord Gurney raised CLmax from 2.2 to 2.3 with similar stall (Selig & Guglielmo). On an advanced airfoil at Re 3e6 a 1.25% flap raised lift substantially but with very large drag penalties at low and moderate CL (NASA TM-4071).
A 5% chord strip gave more max lift but a significant drag increase (Roesch & Vuillet in NASA TM-4071).
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.

Gurney flap size chart

parameter	value or range	source
Liebeck height	about 1.25% chord	NASA TM-4071
S1223 + 1% Gurney	CLmax 2.2 -> 2.3 (Re 2e5)	Selig & Guglielmo 1997
0.0125c strip on helicopter stabiliser	drag unchanged, lift up	NASA TM-4071 (Roesch & Vuillet)
0.05c strip	more CLmax, significant drag increase	NASA TM-4071
Reference build	chord 100, 1.25 mm tab, 90 deg	Liebeck height

Where the files are

Other publishers' files are linked, not hosted. "verify" = check the license at the link before commercial use.

NASA Langley (Neuhart & Pendergraft)	A Water Tunnel Study of Gurney Flaps, NASA TM-4071 (1988)	web	Publisher's page; dimensions are facts
University of Illinois (Selig & Guglielmo), Journal of Aircraft 1997	High-Lift Low Reynolds Number Airfoil Design (S1223)	web	Publisher's page; dimensions are facts

Free files

★ Free files 1 parts. Xem Studio design: free to use, print and sell things from; not to be republished as files. Xem Studio Design License. index.json

gurney-flap-wing-segment

Wing segment with a Gurney flap 2 mm high (2 % chord) at the trailing edge

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Plain text: sheet.txt · JSON: /api/geometry?object=gurney-flap