| The Protar 1/24 Lancia LC2 that I'm building is a primitive kit, with many details that cry for improvement. I decided to take the louver panels as a good subject to try to design and print new parts for. |
| The kit's louvers over the front wheels are very, very simple, and part of a horribly thick piece of the body. After various attempts of making louvers from thin sheet metal, and getting nowhere, I decided to try to model it in 3D CAD, for subsequent 3D printing.
Shown here is the first attempt as an STL export, using this online STL viewer. One area of possible improvement is that the louver facets should be slightly shorter, and the opening angled. The way I drew them now implies that the material has been stretched, whereas it was only bent. I noted that two types of front wheel fender louvers were used on the 1983 cars: one with parallel sides, like I drew, and one that grows wider towards the front. 'My' car had the first type. |
| Reusing the above 3D file, I also designed a replacement louver panel for the exhausts. The 'sheet metal' thickness may look excessive, but I don't want to risk too thin parts at this moment. The Protar manual shows many more louvered panels inside the rear wheel bay, but I'll save these for later. Now the printing! | 
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| Here's the result of the first outsourced prints of my two designs - ignore the bigger part in the middle. And these are the best from four tries.. To be continued. |
| On the fifth print attempt, the parts came out much better. But they are very thin, 0.2 mm, whereas my design was 0.3 mm, which is very thin too. They parts were slightly warped, and worse, they will be very difficult to separate from the supports without snapping small chunks from the actual parts. That's why they are shown with the supports here. Back to the drawing board for another attempt. | 
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| Here's the redesigned part, with doubled thickness (0.6 mm) but leaving the 'ends' of the louvers at 0.3 mm. Also, I chamfered the exhaust opening to 0.3 mm, to 'hide' the parts extra thickness. Hopefully this design will work better? |
| The front fender louvers were redesigned the same way. Over to the next 3D printing attempt.
And I (re-) discovered that the LC2 had louvers in the top of its venturi tunnels too. One more thing to design and have printed! And since the louver panels in the tunnels were unpainted, I noted that they look a lot like the louver panels one can buy at a do-it-yourself store. And why not, it's an easy solution. | 
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| The printed part is near-perfect. But maybe my design was not: it has 5 louvers, and I now count 6 louvers.
While studying reference photos, I noted that one car (0007 in 1985 configuration, as sold by Girardo & Co in 2020) had the six-louver panel mounted upside down - interesting! |
| The exhaust panel is also near-perfect, and a great improvement over the kit part. I cannot wait to install it!
There are plenty of LC2 photos that show louver panels installed in the roofs of the venturi tunnels, at their extreme end. I think they are the same size and shape as the ones over the front wheels. However, I have yet to find a photo of the 1983 version with them, it looks like this was a 1984 update. Therefore I will not install them on my model. | 
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