Re: Why are all airliners white

Date:         17 Sep 97 02:49:20 
From:         don@news.daedalus.co.nz (Don Stokes)
Organization: Daedalus Consulting
References:   1 2 3 4
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In article <airliners.1997.2217@ohare.Chicago.COM>,
Sharat Chandrasekhar  <mcsharat@wyman.com> wrote:
>K_ish (Ken Ishigura) <konish@ix.netcom.com> wrote:
>> ...the Concorde is white instead of the BA gray due to solar
>> heat loading as well as the high skin temperatures generated by
>> aerodynamic friction
>
>Good point. But what about the surface temperature of (subsonic)
>widebodied jets at cruising altitudes (where the ambient temperature is
>well below 0 Celcius)?

It's a darn sight lower than 0C.  Here's a hint -- if you wangle an exit
row seat on a widebody, and get the window seat, make sure you have some
insulation, because your feet will be right beside the door frame, and
the frames conduct heat away like you wouldn't believe -- I put a glass
with ice left from a drink down by the foot of my seat once, and when I
picked it up six hours later, it was still frozen.

>If the surface temp. is lower than or marginally above 0 Celcius, the
>case could be made that enhanced solar irradiation due to dark colors
>could help reduce the interior heating costs, unless there's something
>else I'm not accounting for here.

Bleed air comes from the compressor, and it comes into the aircon packs
*hot*.  You have to expend energy to cool it down.

-- don