Xem Studiomeasured geometry

Library › Aircraft design › Wing planforms ·

Forward-swept wing

What are the pros and cons of a forward-swept wing? · Standard part · basis: Design rules and figures from the cited sources; example geometry by Xem Studio

Also called: forward swept wing, forward sweep, x-29 wing, forward swept wing rc, forward swept wing advantages, swept forward wing divergence, su-47 wing, negative sweep wing, forward swept glider

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

sizes
4 in table

Notes

  • Leishman describes forward sweep as aeroelastically unstable and rarely used, because aerodynamic load twists the tips to higher incidence (ERAU).
  • NASA's X-29 used composite aeroelastic tailoring, letting the wing bend but limiting twist to prevent divergence; reversed spanwise flow kept the tips and ailerons from stalling at high angle of attack, with good control to 45 deg (NASA FS-008).
  • Forward sweep gives an unstable dihedral effect, so it needs more geometric dihedral than straight or swept-back wings (Kitplanes, Wainfan). The X-29 did not show the drag reduction earlier studies predicted (NASA).
  • Used on: Grumman X-29.
  • 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.

Forward-swept wing size chart

parametervalue or rangesource
X-29 span / length27.2 ft / 48.1 ftNASA FS-008
X-29 controllable AoAexcellent to 45 deg; limited at 67 degNASA FS-008
X-29 washwashin toward tip (forward-swept)ERAU (Leishman)
Reference build sweep-30 deg LE (illustrative; no published angle fetched)illustrative

Where the files are

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

Embry-Riddle (Leishman), Introduction to Aerospace Flight VehiclesWing Shapes and NomenclaturewebPublisher's page; dimensions are facts
NASA ArmstrongX-29 Fact Sheet FS-008webPublisher's page; dimensions are facts
Kitplanes (B. Wainfan)Wind Tunnel: Roll's role in lateral stability (2008)webPublisher'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

forward-swept-wing-wingswept planform: span 1000, root 250, tip 120 mm, LE sweep -30°, 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=forward-swept-wing

Forward-swept wing, isometric render of a generated part
Render of forward-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
Swept-back wing, isometric render of a generated part
Swept-back 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 aren't forward-swept wings common?

They tend toward structural divergence and need stiff, tailored structure (ERAU; NASA X-29).