Mailing List lml@lancaironline.net Message #29264
From: <Sky2high@aol.com>
Sender: Marvin Kaye <marv@lancaironline.net>
Subject: The Iceman cometh (down gently)
Date: Thu, 31 Mar 2005 16:49:06 -0500
To: <lml@lancaironline.net>

 

Bill “Iceman” Harrelson, et al:

 

Whilst on the road with the wife and dog (retired, but on vacation?) I got a chance to think a lot about your heavy duty ice experience and those mentioned by others.  In the case of the devil’s horn, I can see where any wing would not only see a tremendous increase in drag but also loss of lift because of the severe disruption of the flow over the wing (and the empennage also).  So…..

 

  1. Do you think that the freezing rain contained super-cooled large droplets?  I understand this to be the worst and almost impossible to create in flight tests.

 

  1. Do you think that Lancair’s being equipped with excess power (more than minimally required in STC’d aircraft) contributed to the successful outcome?

 

  1. Could you report on the tail plane icing?  I read the story of the prolonged climb with the ice locking control surfaces on the IV – Ice buildup on the under surfaces, too?  I have been concerned about the tail because of the sharp leading edges and the potential for building ice first.

 

     4.  What did the plane feel like with the initial partial extension of the flaps – pitch
          and controllability?

 

Now for the poser.  This only pertains to Lancair 235/320/360s and their special wings with reflexed flaps……….

 

We know that these wings have certain characteristics with the flap at zero degrees.  The reflex position (-7 degrees) is utilized to reduce lift and drag with a change in the center of lift causing a nose up pitch (AOA change too).  This is inherent in the design.

 

So, when slowed down by carrying ice would it be better to return the flaps to the zero degree position in order to lower the nose, reduce the angle of attack and increase the lift? 

 

Scott Krueger

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