Mailing List lml@lancaironline.net Message #21997
From: Gary Casey <glcasey@adelphia.net>
Sender: Marvin Kaye <marv@lancaironline.net>
Subject: Re: ES wing incidence
Date: Sun, 28 Dec 2003 10:25:46 -0500
To: <lml@lancaironline.net>
<<Or you could just make new spar plates with an offset hole. I did that.
Very easy.>>

Lots of good comments about relative incidence problems, but most were
directed toward the IV.  Besides the obvious front/rear spar interchange, I
wonder if there are other differences.  I measured the incidence and mounted
my front spar plates in the fuselage with all available play in the main
spar bolts taken up in the appropriate direction.  This reduced the error to
half what it was, but I still remain with an error of 0.3 degrees at the
root and 0.6 degrees at the tip in the same direction.  To move the wings
more than that will require some rework of the holes in the main spars.
There is very little that can be done just by changing the front spar
mounting point.  I have read where some have just elongated the holes to
allow the spar to rotate, but this would seem to add stress to the bolts as
they would no longer be loaded in pure shear.  Or is the difference in
loading so small as to be unimportant?  We're only talking about maybe 0.2
degrees per wing.  The question I had to begin with was whether or not the
original difference in incidence was unimportant.  Someone said that 0.3
degrees was not noticeable in a IV, but at the tip my error is 0.6 degrees.
Assuming the angle of attack in cruise is about 2 degrees either of these
angles should be significant.  Are they?

Gary Casey


Subscribe (FEED) Subscribe (DIGEST) Subscribe (INDEX) Unsubscribe Mail to Listmaster