MakerPlane Open Source LSA Looking for Guidance on Windscreen Design

[JNicol]

Hi Kiwi,

Thanks very much for a comprehensive and awesome answer....! Nicely explained. I will certainly give this technique a shot and report back here. It has probably saved me a lot of time, effort and band-aids. A couple of questions on the sheet metal folding technique used on the rear windscreen, just confirming that you did that cold? Also, did you see any fracturing or was it a clean bend? It looks like it will work on our front screen for sure.

(BTW, found a link to a home-made brake that looks like it would do the job... http://www.ablett.jp/workshop_archiv...me_a_brake.htm)

[Eric Witherspoon]

A couple of questions on the sheet metal folding technique used on the rear windscreen, just confirming that you did that cold?

He's doing that cold. One other point I didn't include in the earlier post about the two common materials - polycarbonate, though tough, attracts scratches like nobody's business. Just cleaning off bugs - scratches. Look at it funny - scratches. Acrylic is more scratch resistant.

One other thing you might want to notice about Kiwi's windshield - the big front section is curved along the bottom edge. Meaning most of what you look through is in fact a curve, and not flat. Just the slight curve is much stiffer than flat. Mock it up with poster board and poke it with your finger.

You might want to consider a curve shape to the top of your firewall in order to get some stiffness into your windshield configuration. Or before you build it on the airplane, at least mock up this windshield on a frame, mount it on the roof of a car, and get it up near 100mph. With some video on it, you can see whether you really want a big flat panel or not.

[JNicol]

It might be that Kiwi's method of construction as described is actually going to be easier and more robust than three flat separate panels, particularly if the brake method works for us. If we allow for a small bow in it when we attach the whole thing it might be enough to stiffen it. The intention is to prototype this on a non-flying full scale model. Blasting it with some wind would certainly help to see if it is wobbling at all.

[Eric Witherspoon]

Good luck - sounds like you're on a path to success. Might be a nice wrap-up to this thread if you could post some photos of what you end up with - and any other comments with windshield development you find relevant.

[Kiwi ZK-CKE]

yes the rear window was bent cold. Its a technique used quite a lot for making clear shelving and display stands and creates a very good result - no crazing or cracking as the the fold is supported during the process. Leave the protective wrap on when doing this - it may also be beneficial to put some masking tape on as well to prevent scratches, because yes, polcarb is really scratch prone!

post pics of how you get on!

[JNicol]

Thanks Eric and Kiwi!

I will certainly post pix of progress, testing and the final installation to wrap things up!

Cheers!