Split flap — dimension sheet
Source: Xem Studio, https://xemstudio.com/objects/split-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 split flap hinges down from the lower surface only, leaving the upper surface in place; it gives slightly more lift than a plain flap but high drag, and fully extended it adds high drag with little extra lift (FAA PHAK ch.6).
- That drag is useful for steep approaches. Arnedo groups the plain and 'intrados' (lower-surface) flap together at a section CLmax increment of about 0.9.
- 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 (intrados flap)  0.9  Arnedo (Franchini)
Lift vs plain flap  slightly greater  FAA PHAK ch.6
Reference build  chord 100, 25% lower-surface flap, 45 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/split-flap/index.json
API: https://xemstudio.com/api/geometry?object=split-flap