[NSRCA-discussion] Design Question

[J N Hiller]

Thanks Lance. I don't want to stray too far from proven relationships but
understand there are many variables rendering each design different.
I presently have the wing located 1/2" below a centerline through the H-stab
and engine centerline. The stab is about 1/2" above the tail tube centerline
and positioned about 1/4 the height of the V-stab.
Both the wing and stab will be adjustable and previsions are included for
changing thrust angles. Tweaking these angles should effectively change the
flying height of the tail but the wing offset remains about the same.
Other than changing the vertical center of drag what are the pros and cons
associated with positioning the wing higher or lower. I'm thinking the
vertical center of drag relative to the thrust line can contribute
significantly to pitch trim. Is it a major influence?
Before beginning to cut parts it occurred to me that the design /
construction detail offers considerable leeway in vertical wing placement,
maybe as much as an inch higher or lower from the -1/2 presently planned and
changing the wing location later will require major surgery.
I guess what I'm really looking for is more understanding of the effect
vertical wing placement has on pitch trim. I guess I asked the wrong
question. Any thoughts on this will be helpful.
Thanks
Jim

-----Original Message-----
From: nsrca-discussion-bounces at lists.nsrca.org
[mailto:nsrca-discussion-bounces at lists.nsrca.org]On Behalf Of
patterndude at tx.rr.com
Sent: Monday, November 09, 2009 2:38 PM
To: General pattern discussion
Subject: Re: [NSRCA-discussion] Design Question

That's all?  There a number of design issues we face in pattern where
there's little documentation readily available. This is one, KE flight is
another, wing incidence and engine thrustline effects in 4 axis flight is
another. The more I think about it the more I think of.
  There's no one answer and anything between the chordline and thrustline
can be made to work by changing rudder shape and incidence. I settled on a
quarter inch above the chordline and then adjusted the rudder to allow a
trim incidence near zero so inverted flight is more effortless.

Lance
AeroSlave
Sent via BlackBerry by AT&T

-----Original Message-----
From: "J N Hiller" <jnhiller at earthlink.net>
Date: Mon, 9 Nov 2009 09:36:13
To: NSRCA Mailing List<nsrca-discussion at lists.nsrca.org>
Subject: [NSRCA-discussion] Design Question

Hello all.
Here's a topic for discussion that I'm personally very interested in and may
be of interest to others.
I'm working up a new pattern design and would appreciate comments regarding
the vertical placement of the wing and thrust line relative to the stab
centerline.
I not only would like to know what the vertical offset is on modern pattern
designs but how the vertical location affects flight trim, and why?
Thanks all.
Jim Hiller



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