The heat gain of different colors go like this: White, yellow and pink, light blue and aluminum (silver), purple and blue, light green, orange and tan, red and green, brown, black. I know of one silver Long EZ and one Berkut, but there's probably others. My Long EZ is yellow. So are the other two EZ's at the Hood River OR. airport.Yes!
Pigments incorporating the oxides of magnesium (white) or aluminum (silver) have similar reflective properties.
If we are resorting to that "temperature graph", the following from EASA CS-VLA is probably a reference with better standing
Only the IR frequencies are important in heating airframes: is this true?Be sure to use a primer that reflects uv, to protect the epoxy.
Visible colors are not what is important for limiting temperature; IR absorption / reflectivity is. There are examples of glass airplanes painted yellow, red, shades of charcoal, etc. One pilot of a dark colored airplane rationalized “It cools off from the propeller blast before takeoff.” The epoxy that you use, and the cure temperature atr relevant, as you said. Bottom line: do research beyond what you read here, and make your d3cision. Remember, E-AB is about experimenting and learning.
I wouldn't try it in New Mexico in the summer...There<s a guy who build up a cozy and it<s all painted in black. Color don't matter at all. It's all about the mission. Do you want to exposed and be the only one.., fly just local. All will be fine. But of course, if you stay outside, in about 3yrs lot of real test with c-t scan will be the best to do. But for 3hr flight per 2 week as the vast majority of people, it's ok.
/snip/ paint pigments are an example of subtractive color. A blue paint appears blue to our eyes because it is selectively absorbing the non-blue colors (red, green, etc) and what remains ( and is reflected to our eyes) is blue.
White pigment works well because light that appears white to our eyes is composed of all wavelength. That paint is reflecting all visible wavelengths and not preferentially absorbing any of them, and that results in a cooler surface.
For homework: Given:
1) A blue paint is preferentially reflecting short visible wavelengths and absorbing long visible wavelengths.
2) A yellow paint is doing the opposite.
3) Per the graph in Post 66, there's more energy in the shorter wavelength spectrum (even after atmospheric effects).
So, why do we observe that blue surfaces get hotter than yellow surfaces (post 65)?
Interesting, but we'd need to adjust for some things.Locate a non contact thermometer.
Locate a Walmart parking lot on a sunny payday.
Note the temperature of each car roof in three categories: silver, white, blue.
When you have at least 16 values in each column average each column and draw your conclusion as to the difference in solar absorption between silver and white, and between either of those and blue.
#1 is a rational point - resolved with a thermocouple thermometer.Interesting, but we'd need to adjust for some things.
1) A non-contact IR thermometer won't tell us the temperature of the roofs. They work by measuring IR radiation and making an assumption about the emissivity of the surface, /snip/
2) Brightness vs hue: I suspect this is the biggest confounding factor. Saying a surface is blue or yellow (its hue) doesn't tell us much about its reflectivity.