Fowler flap — dimension sheet
Source: Xem Studio, https://xemstudio.com/objects/fowler-flap/  (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
- A Fowler flap slides aft on tracks before drooping, increasing both wing area and camber; early extension adds lift with little drag, late extension adds drag with little lift (FAA PHAK ch.6).
- Its section CLmax increment is 1.3 x c'/c, where c' is the extended chord; double-slotted Fowler reaches 1.6 x c'/c and triple-slotted 1.9 x c'/c (Arnedo, Franchini data).
- 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
Section delta-CLmax  1.3 c'/c  Arnedo (Franchini)
Double slotted Fowler  1.6 c'/c  Arnedo
Triple slotted Fowler  1.9 c'/c  Arnedo
Typical CLmax/cos(sweep), Fowler flap  2.0-2.2 takeoff (15 deg) / 2.5-2.9 landing (40 deg)  Arnedo
Reference build  chord 100, 30% flap, 40 deg  illustrative

Files elsewhere (not hosted by Xem Studio; license as stated by the publisher):
- 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
- LibreTexts (Arnedo, Fundamentals of Aerospace Engineering; data from Franchini et al.): 3.4.3 Increase in CLmax (high-lift devices) — web — Publisher's page; dimensions are facts — https://eng.libretexts.org/Bookshelves/Aerospace_Engineering/Fundamentals_of_Aerospace_Engineering_(Arnedo)/03%3A_Aerodynamics/3.04%3A_High-lift_devices/3.4.03%3A_Increase_in_CLmax

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