Canopy thickness...
Hey Bruno,
The sizes are inches in decimal form. For instance 0.22 is 'pretty close' to 1/4, so that's what most folks call it. The same goes for 0.177 which is 'about' 3/16 (3/16 is .187 in the rest of the world).
As far as the difference between workability between the two, I can't tell any difference between pieces from the manufacturer I use, and I've personally ruined a lot of both lately! Maybe different manufacturers glass has different properties.
I just finished an email to another gentleman concerning thickness and it follows:
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I've given the thickness a lot of thought, and personally, I'm going with 3/16 for my RV8 project for two reasons. First the final thickness isn't the same as original once the plastic is formed. At it's thinnest, it's about 1/8 inch (for 3/16 original size), so by the time both sizes are blown, they're about 1/32 different... That's not going to change the results of a bird strike. Bird strikes are a result of bad luck, and whether or not it goes through the canopy depends on how bad your luck is!
Second, and most important to me is weight. Plexiglass is surprisingly heavy, and the difference between 3/16 and 1/4 is nearly 5 lbs for an RV8, probably 3 or 4 for the RV3. To me that's a lot of weight that's doing nothing! If you read my posts you'll see that I'm a little OCD about weight. I built an RV8A that weighed 975 lbs ready to fly, and had amazing performance.
The same plane had a Todd's tinted canopy, and I was very happy with it. The RV6 I fly now has a clear one, and it's like flying a terrarium, hot, hot, hot. Plus I need to wear a long sleeve shirt and hat. That's exactly what I wanted to do in S. Florida on 95 degree days.
Hope this helps,
Lance