Month: December 2023

P-39 Restoration Project: CAD Services

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P-39 Restoration Project: CAD Services

12 months ago I started providing CAD design services to Planes of Fame, Chino to assist them with the restoration of a P-39 Airacobra. This aircraft is a static display restoration so we had some latitude in the manufacturing of the various parts. This included 3d printing (which is done by a professional company), sheet metal work, and vacuum forming.

The CAD models generally are for small complex geometry parts as you can see in the examples posted below. When preparing these models everything is double-checked against blueprints and where necessary the aircraft itself to ensure correct profiles.

I have over 40 years of experience in Engineering Design and drafting; in fact, I actually started my career as a draughtsman on the drawing board. I question everything and take nothing for granted with a focus on detail and accuracy. So when I prepare the 3D CAD models I also create a 2D dimension drawing as a checking mechanism to ensure accuracy and also as a reference for the engineers. If the 2D drawing is actually produced specifically for manufacture instead of being a design check it will incorporate all required standards references, tolerances, and material specifications.

3D CAD modeling of parts for aircraft can be quite complex and can take a long time to complete. The smallest part here would normally take about 3 hours. That may seem a lot of time for small parts that appear to be quite straightforward but often it is the reference geometry not visible that takes the time, whether that be the curvature of the wings or fuselage. Then everything is checked and documented.

The P-39 Restoration project still has a long way to go which I feel privileged to be part of.

If you require parts developed in 3D CAD for your project then please don’t hesitate to drop me a line at hughtechnotes@gmail.com.

I would like to take this opportunity to wish everyone a Happy New Year.

F4F/FM2 Wildcat Progress Update

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F4F/FM2 Wildcat Progress Update

The ordinate dimensional study for the f4F/FM2 Wildcat will now be ready in January. This will include dimensional information for all the rib, strut, and frame profiles fully documented in 3D CAD, 2D drawings, and Excel spreadsheets. Probably the most accurate dimensional study available.

In January I will be taking this project and the P-39 Airacobra to the next level. The plan is to fully 3D model in CAD all the primary structural components for the wings, flaps, ailerons, elevators, rudder, fuselage, empennage, cowl, and landing gear; and then produce a 3D printed scale model at either 1:15 or 1:10 scale. The F4F empennage is already partially fully 3D modeled in CAD which gets us off to a good start in the New Year.

These models will be printed on an Elegoo Saturn MSLA printer capable of producing a 0.02mm accuracy. The resin I will use will likely be PLA with a 10% mix flex resin to minimize brittleness. This is an ambitious project and will take most of the year to complete.

Many of the components are thin-walled profiles which may have to be adjusted to suit the scale of the printed model. Some testing will be done to find the minimum thickness to achieve model integrity and maintain dimensional accuracy.

This project is something I have been thinking about for a long time which is only now possible with the incredible accuracy achievable by the latest 3D printing technology. The final 3D CAD model; suitable for 3D printing; will NOT be available publicly but I am open to the idea of private sponsors.

As usual, all inquiries to hughtechnotes@gmail.com