Xem Studiomeasured geometry

Library › Aircraft design › Wing planforms ·

Swept-back wing

Why do some wings sweep back? · Standard part · basis: Design rules and figures from the cited sources; example geometry by Xem Studio

Also called: swept wing, swept back wing, wing sweep angle, why are wings swept, swept wing rc, swept wing tip stall, sweepback dihedral effect, swept wing washout, critical mach sweep

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

sizes
4 in table

Notes

  • Sweeping the wing raises its critical Mach number, since Mcr for a swept wing scales with 1/cos(sweep) (TU Delft AE1101); sweep is mainly worth it at transonic and supersonic speed.
  • Sweepback adds a stable dihedral effect that grows with lift coefficient, so swept high-wing designs may even need anhedral (Kitplanes, Wainfan).
  • On a swept-back wing the local angle of attack rises toward the tip, so washout is needed to keep the tips from stalling first (R/C Soaring Digest). NACA tests of a 45 deg swept wing showed severe pitch instability without fences (NACA RM A53I21).
  • Used on: B-1 (variable sweep), Boeing 737.
  • 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.

Swept-back wing size chart

parametervalue or rangesource
Sweep measured atquarter-chord line (or LE/TE angles)ERAU (Leishman)
Examplesweep 40 deg with Mcr 0.7 (worked example)TU Delft AE1101
NACA test wing45 deg sweep, AR 5.515, taper 0.532, 10% thickNACA RM A53I21
Reference buildspan 1000, root 250, tip 120, LE sweep 40 degillustrative (TU Delft example angle)

Where the files are

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

TU Delft OpenCourseWareAE1101 Introduction to Aerospace Engineering, Aerodynamics 6webPublisher's page; dimensions are facts
Kitplanes (B. Wainfan)Wind Tunnel: Roll's role in lateral stability (2008)webPublisher's page; dimensions are facts
R/C Soaring DigestTwist Distributions for Swept Wings, Part 2 (June 2002)webPublisher's page; dimensions are facts
NACA Ames (Cleary & Boddy), RM A53I21Wind-Tunnel Investigation of a 45 deg Sweptback Wing ... Including the Effects of Fences (1953)webPublisher's page; dimensions are facts
Embry-Riddle (Leishman), Introduction to Aerospace Flight VehiclesWing Shapes and NomenclaturewebPublisher'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

swept-wing-wingswept planform: span 1000, root 250, tip 120 mm, LE sweep 40°, dihedral 0°, NACA 2412STEP · STL
Let your AI pull this. Add https://xemstudio.com/mcp to Claude, ChatGPT, Cursor or any MCP client (free, no account, one minute) and it can look up exact sizes, mating fits and free STEP/STL from every chat.
Set it up →

Plain text: sheet.txt · JSON: /api/geometry?object=swept-wing

Swept-back wing, isometric render of a generated part
Render of swept-wing-wing from the free STEP; not to scale.

Fits with

Rectangular (constant-chord) wing, isometric render of a generated part
Rectangular (constant-chord) wing6 sizes★ 1 file
Tapered wing (taper ratio for minimum induced drag), isometric render of a generated part
Tapered wing (taper ratio for minimum induced drag)6 sizes★ 1 file
Elliptical wing, isometric render of a generated part
Elliptical wing5 sizes★ 1 file
Forward-swept wing, isometric render of a generated part
Forward-swept wing4 sizes★ 1 file
Delta wing, isometric render of a generated part
Delta wing5 sizes★ 1 file
Cranked arrow / double delta wing, isometric render of a generated part
Cranked arrow / double delta wing4 sizes★ 1 file

Questions

Why does a swept wing tip-stall?

The angle of attack seen by each section rises toward the tip, so washout is needed (R/C Soaring Digest).