Windscreen

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Windscreen

Postby Paul Johnson » Sun Sep 16, 2018 10:20 am

I have recently replaced my windscreen due to it being damaged by a fuel leak, the new one looks great but the polycarbonate (Lexan, Makron) is susceptible to damaged by fuel and scratches very easily. Polycarbonate is much stronger than acrylic (Plexiglas) but acrylic is not affected by fuel and is harder to scratch and is used in other aircraft windshields, has anybody tried making a windshield out of acrylic?
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Re: Windscreen

Postby wlarson861 » Sun Sep 16, 2018 12:44 pm

The downside with the acrylic is it's impact strength. Lexan is used in the event of a bird strike. I have cracked 2 windshields with auto gas and am considering Plexiglas also. I need to test the Plexiglas with auto gas. Acrylic will craze and spiderweb with auto gas when not under tension. Under tension it cracks through and will break based on our trials. If anyone has tried Plexiglas with auto fuel I would be interested with the results.
Bill Larson
N861SX
Sonex, polished, tail wheel, Generation 4 Jabiru 3300
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Re: Windscreen

Postby lpaaruule » Mon Nov 26, 2018 9:38 am

I went flying on thanksgiving day here in Michigan. It was 23F at OZW, and I cut my flight short due to the engine, and myself running a little too cold (even with some air dams in the cowl inlets).

Upon landing, I taxied to the fuel pump to top of the fuel as I normally do. Without gloves, this was a horrible experience and I was definitely rushing.

I finished fueling, and jumped back in the Sonex. About 50 feet later, the fuel door opened and fuel streamed out of the tank, covering my windscreen, and the top of my canopy.

I shut down, jumped out, and sprinted back to the pump to retrieve my fuel cap. I was sure that my windscreen and canopy was ruined. Fortunately I was right in front of the FBO, so I ran in, and wet some paper towels, and wiped off my windscreen and canopy the best I could.

In the meantime, I noticed that in a rush to get my fuel cap, I hadn't pulled the mixture all the way. There was now a puddle of fuel under the Sonex. I had done this one time before during a preflight, and had to remove the intake ducting to let the fuel out. Upon talking to an AP mechanic, he recommended that I drill a 1/8" hole in the duct at the bottom. He said most planes do this to prevent hydrolock due to carb issues.

So after pulling the mixture, waiting inside the FBO for about 15min, and was then able to taxi back to my hanger.

Upon getting to the hanger I sprayed my canopy and windscreen with Plexus, and wiped it with a microfiber towel.

When got back to my hanger few days later, I was pleased to see the windscreen and canopy looking as good as new. I'm still wondering if the windscreen will eventually craze. Maybe it was so cold that the fuel didn't react with the windscreen?

Anyone else willing to admit having a similar experience? If so, any long term damage?
Paul LaRue
Sonex N454EE Plans# 1509
Jabiru 3300
First Flight 12/21/2017
http://www.mykitlog.com/lpaaruule
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Re: Windscreen

Postby wlarson861 » Tue Nov 27, 2018 12:39 am

100 low lead does not seem to attack the Lexan nor the plexiglass. Had that been auto fuel you probably would have cracks by the time you got on the ground. We tested unleaded alcohol free on the wind shield trimmings and it crazed in a few seconds.
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Sonex, polished, tail wheel, Generation 4 Jabiru 3300
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Re: Windscreen

Postby DCASonex » Tue Nov 27, 2018 7:43 pm

Once taxied off in my tail dragger without replacing the fuel cap. It is now tied on end of a cord, like one ties mittens on a kid.

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Re: Windscreen

Postby fastj22 » Tue Nov 27, 2018 9:34 pm

I have spilled 100ll on my windscreen without any effect. However, I did see Jeff Schultz's windscreen craze from the same treatment. Can't say why some do and some don't. Best to keep the juice off the glass. Someone was promoting some sort of "dicky" that you put over the glass and protect any spill.

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Waiex N116YX, Jabiru 3300, Tail dragger,
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