At 08:57 PM 24/11/2009, you wrote:
Hi,
I'm a newbie here........ but I have a question that has intrigued
me for some time....
I have read the GFA/AN53 regarding conspicuity markings, and wonder
why the large under surfaces of a glider are not recommended for
bright marking.
If heat is the issue with anything other than white, and presumeably
direct sunlight is the main source of heat....how do the boffins
reckon that the sun manages to heat the belly and under lower wing surfaces ?
If reflected or convected heat from a tarmac or concrete ground
surface is a problem, surely the fact that the patch under the
glider will be in shade, would greatly reduce this ?
Try albedo.(reflection of incoming short wave radiation. Also
outgoing long wave infra red. (Check what the colour looks like in
long wave IR) Also convection. Shade doesn't help much. The wind is
usually blowing and there is horizontal transport of heat by air
movement (advection).
I once dumped the water out of the wings after sitting on a bitumen
runway for several hours and took off my shoes and socks and found
the water was almost at the point of being unbearably hot. I'm sure
the aircraft designer would have been appalled.
Mike
Borgelt Instruments - manufacturers of quality soaring instruments since 1978
phone Int'l + 61 746 355784
fax Int'l + 61 746 358796
cellphone Int'l + 61 428 355784
email: [email protected]
website: www.borgeltinstruments.com
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