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Date: Sat, 17 May 2008 21:52:24 -0400
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From: "Michael Newman" <mnewman@dragonnorth.com>
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Subject: Optimum Bank for return to Airport turn
Organization: Dragonnorth Group
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When turning back to the airport after an engine failure (rope break for
glider pilots like me) there is an optimum bank angle. Perhaps someone can
enhance the race turns.xls spreadsheet with the correct formula for height
lost in the turn.

Sink rate increases with G load (bank angle) increasing height lost per
second. 

Rate of turn increases with bank angle and thus a decrease in time in the
turn and total height lost for a 180 degree turn.

The optimum does occur about 45 degrees. The penalty for steeper bank (up to
60 degrees) is small.

At coordinated steeper banks there is actually little risk of stall spin,
you don't have enough elevator.

When we train glider pilots for rope breaks we teach them to lower the nose,
keep the 'ball centered', and to use a very steep bank. My pre-solo glider
students are all taught a rope break at 200 feet (an impossible height for
our Lancairs). One surprising observation is that once you accomplish the
emergency course reversal during which you are desperate about being too low
you are high for a normal landing on the runway. The more wind the worse
this situation gets.