Customizable NACA 4415 Aerofoil Section with Reference Lines - Parametric

A customizable NACA 4415 aerofoil wing section with the four classic construction lines printed onto the end face in color: chord line (red), camber line (blue), max-thickness line at 30% chord (brown) and leading-edge radius circle (green). A classroom and desk reference model for aerodynamics - free for students, teachers and makers.

Built entirely with native TrueGeometry Playground commands (the new /aerofoil naca generator plus simple line parts). The section follows the exact NACA 4415 ordinates: 4% camber at 40% chord, 15% max thickness at 30% chord, LE radius 1.1019 t^2 c.

Customize it: chord and span are simple variables (presets for 100, 120 and 150 mm chord included, with full swap-in line blocks in the recipe). Change the NACA code in /aerofoil naca to any 4-digit profile.

Blog article with the full build story, variable tables and technique:

https://blog.truegeometry.com/0_0_0_0/blogs/post-1340913b.html 

Build or customize it live in the Playground:

https://www.truegeometry.com/CoreWebGLTG/KBEAgentHTTP.html 

Full TrueGeometry Playground commands: in the blog article above and in the attached recipe file (naca4415_playground_recipe.txt). A how-to-run guide PDF is attached with a customize-in-Playground section.

Files: full assembly STL first (wing + all four lines, one piece), then the bare wing section STL, the recipe txt and the guide PDF.

Print: PLA or PETG, 0.2 mm layers, 3 walls so the 0.6 mm lines survive. Lines sit 0.5 mm proud of the end face with a deliberate 0.15 mm embed (the only intentional intersection). Untested on a real printer - please print it and post a Make to help the community.

License: CC BY-NC 4.0 - commercial use requires TrueGeometry's consent, please ask first. AI-assisted design: Yes.