Slotted flap — dimension sheet
Source: Xem Studio, https://xemstudio.com/objects/slotted-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 slotted flap opens a gap between wing and flap so high-pressure air from below energises the flap's upper surface; it raises the lift coefficient significantly more than plain or split flaps and is the most popular type today (FAA PHAK ch.6).
- Its section CLmax increment is about 1.3 vs 0.9 for a plain flap (Arnedo, Franchini data); large aircraft use double or triple slots (FAA).
- 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  Arnedo (Franchini)
Wing delta-CLmax  0.92 x dCl x (Sflapped/S) x cos(sweep)  Arnedo
Typical CLmax/cos(sweep), slotted flap  1.5-1.7 takeoff (20 deg) / 1.8-2.2 landing (40 deg)  Arnedo
Typical CLmax/cos(sweep), double slotted  1.7-1.95 takeoff (20 deg) / 2.3-2.7 landing (50 deg)  Arnedo
Reference build  chord 100, 25% flap, 40 deg  Arnedo landing setting

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/slotted-flap/index.json
API: https://xemstudio.com/api/geometry?object=slotted-flap