How thick is the Lexan on the faster Kitfox?

[rogerh12]

Howdy All;

I am about to install a custom windshield on my Model-4, but to cut down on noise I figured I would use the Lexan thickness as used on the Faster upper models.

Does anyone know what the Front Winshield Lexan thickness is on these faster speedwing models?

Is there anything special about the Lexan (coated, UV protect, colored) used on these planes? I can special order a large sheets locally with options



Roger

[HighWing]

Roger,
Typically the local folks here sell the Pollycarbinate (Lexan) in fractional inch measurements - 1/16" (.060) 3/32" (.093) and 1/8 (.118) and up. The Speedster first came out with 1/8" then went to the 3/32 because of installation and crazing issues. The 1/16 was used in the non Speedster models. I have the .093 in mine as that is what came with my second hand kit, but I will switch out to the .060 when the time comes to replace it. I put 900 hours on my first .060 windshields - Changed out once due to the inevitable surface scratching. both eventually developed the crazing at the corners, but not an issue - at least for me. My first airplane's ASI pegged at 120 mph and I had it pegged on occasion with minimal oil canning of the windshield.

A couple of things to keep in mind. the manufacturers recommend a minimum bend radius of 100 times the thickness. The .093 for example needs 9.3 inches, or on other words you can make a cylinder of about 18 inches diameter and it will last forever. In our application, at the wing root, we bend to a radius of about two inches or less. This is why we get the fine craze lines eventually. The abrasion resistance adds tons more inches to the minimum bend radius as it is coated with a very hard thin laminate which will crack if overbent. The color is not an issue, I don't believe. Cold forming in a brake is not an issue in the thicknesses we use. The Lexan turtle deck is formed this way.
Lowell

[HighWing]

I forgot to mention that the abrasion resistant version is designed for glazing purposes and the minimum available thickness is 1/8" (.118").
Lowell

[DesertFox4]

My first windshield on my model 4 was (.093) Poly with no coatings or tint and lasted 8 years. Would have gone further but got tired of looking through the crazing at the roots. Replaced with (.093) again. I can cruise at 120 to 125 mph with little or no deflection. I start to get some minor deflection in the (.093) at 130 to 140 mph.

[rogerh12]

Thanks for the info guys, I did't realized winshield selection was such a science !!!!

Ok, got lots to think about now. But first my Model 4 needs some fabic, so I guess I don't actually have to install the windshield right away (that's fine with me) Plus my BD-4 needs a new to skin (dang hail) and that will keep my busy for a while.