Nose high during cruise?

From:         sdd@larc.nasa.gov (Steve Derry)
Date:         07 Mar 94 15:12:33 PST
Organization: NASA Langley Research Center, Hampton, VA  USA
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On many flights on jet airliners, I have noticed that during cruise the 
aircraft appears to maintain a nose-up pitch angle.  This is not only 
based on personal perception, but also the stewardesses say that the push 
carts tend to move downhill (i.e. toward the rear of the aircraft).

Now during straight-and-level steady-state flight, the only noticeable 
body acceleration should be gravity, which is balanced by upward lift.  
All other forces should be balanced so as to produce no acceleration.

I thought that for efficiency, airliners were designed with the 
appropriate angle of incidence between wings and fuselage so that at 
cruise angle of attack, the fuselage would be "level" with the oncoming 
airstream to minimize drag.

Why then do I notice this "uphill" effect?  Is the fuselage actually 
pitched up slightly?  I have noticed this on many flights on jet 
airliners, but have never noticed a "level / nose on the horizon" 
attitude during a lengthy cruise. 

--
Steve Derry
<s.d.derry@larc.nasa.gov>