Mailing List lml@lancaironline.net Message #48600
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From: Bob B. <rbelshe@comcast.net>
Sender: <marv@lancaironline.net>
Subject: FW: Vortex generators tame stall
Date: Thu, 28 Aug 2008 07:51:40 -0400
To: <lml@lancaironline.net>
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Here is an alternative to stall strips which I am satisfied with.    I'm not a test or pro pilot, just came up from Cessnas to a Lancair 235 about 12 years ago.  I have reached the magic 1000 hr mark.   I lifted these pictures from my web page, so  if you can ' t see anything, try the link at the bottom.
 
June 2004 :   I installed a Pacific Northwest Aero vortex generator kit.   The kit came with a diagram of the Lancair wing with VG  locations specified and a template to ensure the correct angle for each pair.  I used the suggested locations, and used the supplied double-sided carpet tape to stick them on.  The VGs changed the stalling characteristics from a very quick and frighteningly steep break to a sort of mush, with the nose staying high.  While the ailerons become soft, you can still gently rock the wings.  Pictures below.
 
 
 Vortex generator closeup.    This is the recommended configuration with VGs configured from fuselage to tip.     
In this configuration, I estimate the cruise speed is reduced by about 5 kts.  
With stick full back, nose is very high,  plane is descending about 700 fpm.  Indicated air speed is about 50 kts.

 

 Current vortex generator configuration:   I found that having VGs only in front of the ailerons gives about the same stall performance,
and should be less draggy than the full configuration. 

After 3 years, the VGs are still held on by the carpet tape.   I have only lost one.

Bob Belshe
Moraga, CA
Lancair 235/320  
http://home.comcast.net/~rbelshe/

 

 

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