On Saturday, 20 April 2019 02:18:13 UTC-4, David Hirst wrote:
....SNIP...
If you think of a glider canopy as an SPF100 layer, you won't be far off.

....SNIP....
As previously stated, your biggest danger is in hanging around on a sunny airfield,
....SNIP...
DH
TX

Is that really the case David? It is the first time I have heard about this..
I recall being told that the plexiglass was doing nothing to protect against
UVA & UVB. This is still what I preach at the X-country lecture that I give at
my club. If what you claim it true, I'd have to change my storyline and workflow.

Having been more than once incommodated by an aweful mix of sweat and solar cream in my eyes while airborne, I would really like to get away from "buttering" up before a flight. I can see the point of protecting our skin while running around the airfield but right now my routine seem reversed: I wait
until the last minute to layer the sunscreen on my face, hands, neck and ears just as I climb in the cockpit for my XC flight

Can anybody challenge David's claim here?