Richard,

In case you are not aware of the HP-18 sailplane mentioned in Bob's
comments, it was designed by Richard Schreder and has aluminum wing skins
bonded to foam ribs. As all epoxy glues, the glue used to bond the skins
weakens when heated. As a result time parked on the ramp on a hot day and
color are very important issues for the HP-18. My guess is that the bonding
concerns is what lead Jack to run the tests and resulting article for the
Soaring Society of America.

Here are links to a HP-18 picture and a couple articles.
http://tinyurl.com/2uv7rn
http://tinyurl.com/2vgfl3
http://tinyurl.com/2pw3l5

Wayne
HP-14 "6F"
http://www.soaridaho.com/Schreder

"Richard Riley" wrote in message
...
On Fri, 16 Mar 2007 20:52:15 -0700, Bob Whelan
wrote:

To get an approximation of peak temp possibly expected for a specific
color on a glass sailplane: select the color & determine the max ambient
expected (for that area). On the curve baseline, find the ambient and
move upward vertically to the appropriate color line, then move
horizontally to read peak (surface) temp on the vertical scale.

End of paraphrasing/excerpting...

As I recall from decades-old gleanings from "Soaring" mag, Jack Greene:
a) was an engineer in real life (don't remember what field); b) was a
homebuilder (HP-18 and others???); and c) had an engineer's grasp of
structures and V-n diagrams, etc. My opinion is the data plotted on the
Color Curve Sheet was sensibly and meticulously gathered, and is usable
engineering data. FWIW, my own observations of the man are through the
eyes of a non-practicing aerospace engineer (1972), and glider
pilot/nut. YMMV.

Thanks, Bob. Though that's not good news for this particular project,
it saves me a lot of work.