3d printed oil cooler duct

[U2fletch]

While we wait four our BH5 kit I am trying out some techniques that may become very useful later. Our Glasair Sportsman that we recently acquired has the oil cooling issues typical for that design. One weakness is the stock oil cooler duct. Here is the current duct which has poor flow across the face of the 17 row Pacific Oil cooler. Glasair later included ducts that were longer and had a better shape to them.

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I designed a concept duct and printed it using glass filled ABS. ABS as a material is nice because you can coat it with acetone after printing and this will melt the layers together and greatly improve strength and surface finish. The idea is to then cover the thin ABS part with epoxy and glass cloth for strength.

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That part looked okay, but I was guessing on the cooler dimensions so it was just a trial.

Once I got out to the aircraft I measured the actual cooler and its mounting holes. So made another piece. This was printed in PLA just so I could do a test fit. Once the fit is confirmed I will make a real part with ABS. I have a couple engine mount struts to work around so this may take a few iterations. The mounting holes are 8” across and the duct is 5.5” wide.

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More to follow once I do some test fitting.

[Steve W]

That is absolutely a magnificent piece of art. I’ve spent many hours forming and fibreglassing cooler ducts and never considered what a 3D printer could do. Beautiful piece and great example of what technology and the people who learn it’s capabilities, can do.