Mailing List lml@lancaironline.net Message #25739
From: <Sky2high@aol.com>
Sender: Marvin Kaye <marv@lancaironline.net>
Subject: Re: [LML] Re: So Has Anybody Fully Stalled These Things?
Date: Thu, 23 Sep 2004 11:43:08 -0400
To: <lml@lancaironline.net>
In a message dated 9/23/2004 8:59:35 AM Central Standard Time, MikeEasley@aol.com writes:
Why am I bringing this up in a discussion about stalls?  I think this kind of stuff will affect how a specific plane behaves in a stall.  One guy has very symmetrical wings and he breaks straight ahead, another guy has some uneven twist and he gets a significant wing drop.
Mike,
 
This is why I believe each hand built Lancair is different.
 
On my slow-built 320:
 
1.  While the wing jigs were very carefully and exactly positioned, one point was not verified.  The trailing edge of the fuselage wing fillet was later found to be different by 1/2" (from lateral level) from one side to the other.  Thus the flap construction and the chord line differ slightly from side to side with some builders seeing a "heavy" wing.  This can be altered by rigging the cruise flaps to account for this.  If there was any variance in the angle of setting the stub wing flap bell cranks (differing from 63 degrees, off in tilt, etc?), the extension flap travel may differ from side to side.  Thus the airplane may stall differently with flaps retracted or at any extension position (-7 thru 45 degrees) because of roll tendencies.  If I remember correctly, Mark Ravinski adjusted the flap rigging on his 360 to make it behave better in stalls.  I think some builders spotted this problem during construction and adjusted the fillets before completing the flaps and ailerons.  I know that when I slooow down in the pattern with flaps at about 15 degrees and rudder trim adjusted, I should re-trim the ailerons.
 
2. The next time a gaggle of 320/360s are sitting around, go stand at the prop spinner of each and, using both eyes, look at the top of the vertical stabilizer.  When I last did that some years ago, about 50% are like mine, slightly twisted.  After all, in some cases I believed the molded part was "accurate" (well, I was a tyro).  I must do a survey and relate this to slow or fast built.  I don't know how much this twist affects stall/spin recovery.  There is evidence of differences by the way people have described rudder trim management at cruise and slow speeds.   Please remember that, like most builders, I am an "untrained" test pilot.  I do read a lot though.
 
Then, are you sure the "ball" instrument is orthogonal to the aircraft axes?
 
 
 
Scott Krueger AKA Grayhawk
N92EX IO320 Aurora, IL (KARR)

Some Assembly Required
Using Common Hand Tools.
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