Wind Tunnel Blades Get Reverse Engineered

GM Needs a Refresh

More than 40 years ago the General Motors wind tunnel began testing the aerodynamics of all its vehicles. For this purpose, a large full-scale wind tunnel was built. At the heart of this wind tunnel is the massive turbine wheel with 5 blades turning at high speed. Each blade is more than 220 inches long and is crafted to be relatively lightweight. However, due to the size of the blade, they still weigh about 1 ton each.

During the course of usage over the last 40 years, the tips of the blades were wearing off, and the engineers were also worried about the structural integrity of the wooden structures. This led them to the decision to have these blades fully 3D scanned and reverse engineered so that they could be replicated.

So, using our Surphaser long-range 3D laser scanner, each surface of the blade was captured all the way around. Altogether, millions of measurement points were taken over the surface of the blade thanks to the high-resolution scanning. Complete details of the wear and tear were captured during the scans.

Another complication during the scanning was the hidden hub portion of the blade. Furthermore, all blades are assembled in a very tight hidden hub with 12 large bolts, with asymmetrical mounting, for foolproofing. The mounting portion of the blade needed to be scanned from up inside the center of the turbine, and then the scan data matched up to the outer blade surface data. A few hours of scanning, processing, and matching all the scans together resulted in a high-resolution polygon mesh, which was then exported to an STL file. Furthermore, an STL file is a tessellated mesh of triangles connecting the millions of measured surface points.

Reverse Engineering the Scans

The STL was then aligned to a logical coordinate system, using the mounting surfaces and features on the blade. This was done to ensure proper modeling and fitting of the blade in the assembly after the re-manufacturing.

Detailed linear cross sections for the actual blade shape were created from the scan data. These cross sections were fitted with smooth spline curves, which were then split up, based on the curvature values and inflection points. Each individual feature on the surface was then made into a NURBS surface, and error-checked with the underlying STL surface, for accuracy. These individual surfaces were then trimmed, stitched, transitioned, and merged with the surrounding surfaces for a smooth and accurate water-tight solid model.

The final CAD model was then used to manufacture five new blades for the wind turbine. After all the gluing and assembly of the Spruce wood panels, the new solid model math data was used to cut the exact blade shapes on a CNC milling machine. Finally, the finishing touches included gap filling, surface polishing, and a final application of protective varnish.

3D scanning worn out blade — Wind Tunnel

3D scanner turbine blade — Surphaser 3D Scanner

Wear tear replace blades 3D scanning — Thwear and tear on the 40 year old blades

Converted STL 3D laser scan data — 3D Scan-data

turbine blade cross sections iges — Cross sections created from the STL

blade 2D cross sections from 3D scan — Top view of the Cross sections

Reverse Engineered CAD model — Finished model

Kyle Keiser

October 31, 2023.

Great service and responsiveness. The data they provided was cleaned up well and accurate.

C S

August 7, 2023.

WOW! What a great experience. Applications 3D provided us with the best looking scans I've ever seen. Fast, friendly and affordable. I can't say enough good things. Thanks again Raminder!!

Travis O

July 13, 2023.

Really quick and great work. Applications 3D made sure that I received everything I needed for my project.

Eric S

April 25, 2023.

Raminder did a fantastic job scanning some parts for me. VERY reasonable pricing for the quality of scan provided and the turn around time was ridiculously fast. 10/10 would recommend and will be using again!

Adam Barton

March 8, 2023.

The Applications 3D team is a pleasure to work with. They have provided our organization with 3D scanning, reverse engineering, and CAD model creation services. The pricing is great and they have quick turn around times.

Namsag

January 30, 2023.

I found Applications 3D online, wanting to get an item scanned accurately. Couldn't have been happier with their services. They were fast, great communications, and the end result was excellent. I will use them again in the future. This job was for an individual project and they did not hesitate with their services. It was also at a lower cost than I could find anywhere in my state. Highly recommend their services. Thank You Raminder-Applications 3D

Dan Dwyer

January 24, 2023.

Very professional and in depth and detailed with his work. You might find a cheaper source but not a better one.

Ivan Fucich

September 9, 2022.

I approached Applications 3D with an existing 3D scan file that I didn’t know what to do with. After speaking with Raminder over the phone, we scheduled an appointment same day to review the file. He looked at my file, and gave me a quote for his service - to produce a Step file that could be used to CNC a master mold from the shape that I had scanned. He was finished with the design in 1 week, but there was a slight issue which I brought to his attention, and he immediately worked on creating a solution, which was resolved by the end of that same day!! I honestly couldn’t be more happy with the result, and very much look forward to working together with Raminder & his company again for more 3D modeling work.