Bubble canopy / solar heating -- addendum

I was reminded, in an off line conversation, that UV intensity increases
with altitude. Therefore, the skin cancer risk that I always regard as
exagerated at sea level is much more worthy of concern--and therefore of
prevention--at altitude. The higher you go the more important it gets, and
sailplanes spend a lot of time above 15,000 feet; but even my own plans to
fly a lot between 8,000 and 10,000 feet mean that this issue deserves a lot
more attention than I have been giving it.

Canopies by Ray Poguette of ThermoTecUSA.com were mentioned in the
conversation, giving excellent UV protection. A tinted version for reduced
heating is also offered. (Required disclaimer: I have no connection to
this company)

A quick web search also yeilded a little information on a GE product called
"Solar Control Lexan" which is stated to be both cold bendable and heat
formable and which they are recommending as a clear cover for excalator
tunnels--which might be exposed to sun, rain, and hail. The Lexan is
advertised as an IR (heat) blocker, and may also be an inherent UV
blocker--I do not know whether all, or only some, polycarbonates are UV
blockers--only that the polycarbonate used for eyeglass lenses is rated at
99% UV suppression. In addition, I found some references to scratch
resistant UV blocking coatings to be placed on the outside of windows and
scratch resistant IR coatings to be placed on the inside.

The bottom line is that canopies which are transparent to visible light, but
nearly opaque to both UV and IR are coming soon--and some may be here
already.

Peter