Mailing List flyrotary@lancaironline.net Message #59093
From: Jarrett Johnson <hjjohnson@sasktel.net>
Subject: Re: [FlyRotary] Re: skydivers-supersonic-24-mile-jump
Date: Mon, 15 Oct 2012 13:45:44 -0600
To: Rotary motors in aircraft <flyrotary@lancaironline.net>







Jarrett Johnson <hjjohnson@sasktel.net> wrote:

"""Some of that temp rise will be aerodynamic heating. I know at 280knts and
24,000ft I'm seeing 10-15decC rise in temp... At 800+mph the temp rise would
be a lot higher, even at 70K+ ft.
"""

Airspeed definitely wasn't the case here.. this was during the ascent, when he was rising about 1000fpm, maybe less (don't remember exactly) but his speed over the ground had by then diminished to 15-20 knots, just floating along with the flow up there.  I, too, am curious about why ambient temps started to rise as altitude increased... I'd have figured it to just keep going down right in step with the ambient pressure.  It'll be way interesting to hear the actual reason.

  <marv>

 

OOps.. sorry I missed that point!  I wonder if it's due to
solar heating of the toropopause?  If you look here  http://www.engineeringtoolbox.com/standard-atmosphere-d_604.html
you'll see 
that there is actually an increase in temp at those
altitudes?  I'm not sure as to the 'why' but it appears that it does. I recall
being told this during my ATPL groundschool but couldn't tell you 'why' it gets
hotter..
 
Fwiw
Jarrett


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