Re: 90 degree angles

From: (Jim Wolper)
Organization: Idaho State University, Pocatello
Date:         13 Apr 95 10:46:52 
References:   1
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>Is it posible for an aircraft's hull to withstand a ninety degree turn
>maintaing it's current altitude at speeds above 250 Mph? By ninety degrees
>I mean an exact right angle.

This question is a little vague, so I assume the poster means that
the aircraft is in coordinated level flight with a bank angle
of 90 degrees.  The load on the aircraft is proportional
to the secant of the bank angle and completely independent of
the airspeed, so in this case the theoretical answer is "no"
since the load factor would be infinite.  In contrast, normal
category aircraft in the USA have a limit load factor of +3.8g
(which corresponds to a bank angle of about 75 degrees) and 
utility category aircraft have a limit load factor of 4.4 degrees
(corresponding to a bank angle of about 77 degrees).

Some may have observed aerobatic aircraft in "knife-edge" flight;
this is not coordinated, however, as some of the lift is provided
by sideslip (top rudder).

[pet peeve: "it's" is a contraction for "it is".  The possessive (genitive)
form of "it" is "its".]
Jim Wolper CFII
Department of Mathematics         <email:>
Idaho State University
Pocatello, ID  83209-8085  USA