danlj wrote:
The canopy on my '93 Ventus looks clear, but I don't use sunblock and
have never had a hint of sunburn in it, so it must block UV. Three
years ago, I gave a friend a 3-hour ride in a rented Grob and that
canopy *obviously* didn't block UV - I could feel the difference in my
skin immediately. Sunblock was obviously needed.

Are you sure you can feel UV? Did you feel the UV before you got into
the glider, or only after you got into the glider? Any plastic used in a
glider canopy will block substantial amounts of UV; some will block all
of it. And that's with untinted plastic.

As others have noted, to block UV is not the same as blocking heat. If
it also blocks IR, it will look blue-ish.

Other tints will also block IR. The amount blocked will depend on the
particular tint material and the amount. Take a look at the different
tints used on car windows. You are not stuck with blue, unless that's
all the glider manufacturer offers. Thermotec offers gray, for example,
for replacement canopies.

--
Eric Greenwell - Washington State, USA
* Change "netto" to "net" to email me directly

* "Transponders in Sailplanes" http://tinyurl.com/y739x4
* Sections on Mode S, TPAS, ADS-B, Flarm, more

* "A Guide to Self-launching Sailplane Operation" at www.motorglider.org