Hello All,
Unfortunately, I may need to replace the Lexan Windscreen on my B model Sonex project (in addition to already replacing the plexi Canopy months ago). I had posted last year about getting thread cutting oil (just ignorance) on the canopy (and Windscreen) when drilling the holes in bows and it resulted in extreme cracking of the Canopy (and I had to replace it). Sadly, the Lexan Windscreen is doing the same thing now (albeit not as bad), it just too longer. I’m trying to stopdrill and salvage things, but replacement may be necessary in order to ever fly.
I’ve searched the forum (beg forgiveness if it’s there) and didn’t see any posts that describe steps, i.e. HOW others may have gone about getting the bad windscreen out and getting the new one (again, after all the installation riveting and fasteners have been completely put in). Any suggestions (or where it is on the forum) on this would sure be appreciated.
Thanks!
Neil Payne
Not sure how different the B model is, but for the A model it’s just unbolt and remove. I’d probably lay the old one out flat, transfer the shape and maybe holes to the new windscreen.
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Agree with Bryan with the following advice;
Be sure the old windscreen is fitting (holes & dimensions) as you would want. No point in using a bad pattern (old screen) to make a new screen. 
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Just be sure any and all tools used to cut or drill the Lexan are free of all oils and other contaminants, and that all edges are sanded smooth and holes deburred.
David A.
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Yea I believe just undoing the 100 nuts holding it and sliding it out should do it. Getting the new one in won’t be easy but doable!
I used alot of cutting oil on the titanium gear legs. Everything that stuff touched has some of weird fuzzy corrosion on it now. My drill press has this icky rustyish fuzz all of it and the surrounding area. It ate the paint off a workbench I am using as well. Apparently tapmagic cutting oil has chlorine in it which attracts rust…yay.
Perhaps opening the holes up another 1/32” will aid in getting things lined up again?
Thank you all for weighing in! I realized after posting initially that the Legacy Windscreen was not under a skirt like the B Model so to many, it would seem a somewhat silly question. As you said “SNB0047”, it won’t be easy but where there’s a will… (BTW my kit is #SNB0048)
As stated initially, I may be able to delay replacing the windscreen for a while (by stopdrilling and maybe cementing with Acrifix), But eventually the cracks will probably win. That threading/drilling oil is mean stuff in the wrong place; WARNING! Do not get it near the Lexan or Plexi Canopy. Will report back if/when I know more.
Neil P
Followup to the story: A few weeks ago, I finally ordered another windshield from Sonex Aviation and S. Osborne was on the return address name - it came to my home within about a week of making the order.
The removal (of cracked original W/S) and replacement (new W/S) went better than I thought, the new one (installation) was finished up yesterday, now I can get back to the Aerovee Turbo assembly (just wanted to get the windscreen rework done while wx is hot).
A key tool for the removal and installation was firmly taping a small open end 5/16" wrench to the end of a small dia alum rod (about 30" long). This allows reaching the forward most nuts that hold the windshield to the skirt (of course the Skirt machine screw heads are simply turned with a screwdriver from the outside). I also used a small square of good masking tape (green frog tape) to hold the nuts in place on the wrench end, when reaching inside and centering them on the screws, then just start turning the screw from the outside, and it worked well. I could easily remove the “custom wrench” from the nut after it was tight. For photos and more detail you can check the project on EAA Builder’s Website (zip 79424 - Neil Payne’s project).
FWIW. I had asked the Factory, weeks ago if they had any advice on removing and replacing the windshield on a B Model Sonex - they did not and were not aware of anyone who had done it. So, if your B model needs a new windscreen, it can be swapped out and it’s not terribly hard, just takes patience and diligence, like the whole project in general. Also, Sonex Aviation sent the new windshield (just as the original) all precut and almost perfect for install (after smoothing edges and drilling holes), the brand is now Plaskolite/Tuffak - the original was Saibic/Lexan. My research said they were identical polycarbonate sheet material.
Hope this info benefits someone.
Neil Payne
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I don’t know how all my secrets keep getting out!
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Oh, boy, wish I could say great minds think alike but that would drag you way down to my level and wouldn’t be fair, Ha !
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Most of my best ideas are stolen from somebody else!
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"I finally ordered another windshield from Sonex Aviation "
I hope you got it for a good price.
I would have costed out a few polycarbonate suppliers and purchased from the least cost, including delivery.
I know what you mean. In the big picture wanted to buy from Sonex if possible and the price seemed reasonable (much better than the second canopy I had to buy last year that was almost $800 with shipping to my location- of course that’s sort of comparing apples to oranges). Total cost for the new windshield was approx $440 including shipping and it was cut to fit by factory-just as original in kit was (only needed very minor edge trim at one place and then of course had to drill out holes for screws and Popit Air vents, that I chose to add, on both sides). Of course I sanded and gently shaped all perimeter edges to hopefully keep the stress cracks in submission. So far all is good.
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Yes, it’s not always about saving every last penny. If we don’t support the factory (within reason) it makes it harder for it to exist… And, the upside here was you didn’t have to do much trimming which otherwise would have increased the risk of damage/cracking etc.
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Great advice Murray.
Can’t see you ordering a windscreen or canopy from Sonex. The delivery alone will require the sale of your first born.
You can get a Polycarbonate 3 x 1220 x 2440 mm, clear sheet, for about $193 Au+ delivery.
An Acrylic for about $ 125 Au + delivery.
If you want an Acrylic shaped to fit (canopy), contact Ian Link, Aviation Acrylic Mouldings, sailplanecanopies@gmail.com
Slightly related - My first polycarbonate windscreen, a tinted one supplied from the USA , had a number of quite dark blemishes within the material . I didn’t find this out until I had cut, drilled, fitted the screen & removed the protective films. Naturally the blemishes ended up being right in front of the pilots seat/my eyes - no refund from supplier.
I cut my original windshield a tad too short. A friend told me to go to plastics company and i bought an entire sheet of bronze lexan which will give me 2 windshields from a 4x8 sheet.. Also, this was a local trip saving on shipping. I know you were asking about installation but i thought to add this information to the thread.
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