[NSRCA-discussion] Partner set-up question

[Claude Weimer]

Funny you should mention bending the wing tube. I don't know how long you
have been involved in pattern but in 1990 a guy named Doug Ferguson designed
the FRESH AIRE. Doug was flying it on the maiden flight and it had some roll
coupling so he pulled the wing tube, leaned against a fence post, and kicked
it. He picked it up looked at it said "that looks about right" stuck it back
in the airplane took of and there was no more roll coupling. I thought that
was the coolest thing I had ever seen at the time. 

 

  _____  

From: nsrca-discussion-bounces at lists.nsrca.org
[mailto:nsrca-discussion-bounces at lists.nsrca.org] On Behalf Of
Rcmaster199 at aol.com
Sent: Thursday, October 19, 2006 8:03 PM
To: nsrca-discussion at lists.nsrca.org
Subject: Re: [NSRCA-discussion] Partner set-up question

 

Claude, adding dihedral to a plug in wing shouldn't be that tough unless you
are using a carbon tube. If ally, just bend it a bit, say maybe 2 degrees in
the middle of the tube and lock it in place in the fuse do its doen't
rotate.

 

In one of Flying Models issues, Dean talked about that kind of situation
where model pitched differently with either rudder. It's a tricky thing to
fix but not that bad. Adding about 1/2" ventral below the stab would help.

 

MattK

 

 

In a message dated 10/19/2006 8:00:57 PM Eastern Standard Time,
geobet at gis.net writes:

Claude,

I have to confess that most of my opinions are based solely on the empiricle
results of building my own designs and finding out through experience what
works. I'm sure you're aware that "what works" for one individual is not
always going to be "what works" for someone else. To demonstrate, in my
opinion, the Eclipse you had with the stab at the 3/8" lowered point was as
close to neutral as is possible with the design. If you have a plane that
pulls with one rudder and pushes with the other that should be equalibrium
and the mixes to trim this out should be in the 2% bracket. You can't see 2%
!  When you raised the stab back up, the rudder that was pushing should have
seen an amplification of that problem, so I would have to conclude that your
"little adjustment" altered something additional to affect the aerodynamic
effects involved.

I also like to see a design that requires as close to zero mix as possible,
but as you are aware there are many many variables to overcome and
aesthetics can often

complicate desirable characteristics to the point of compromise. 

The numbers I quoted are nothing more than good sounding measurements based
on the limited info available. It really gets a lot more detailed than can
be resolved without actually seeing the airplane and doing some actual
measuring, however, the dihedral thing is probably a real close
guess.....and yes it's as tough to change as you think especially with plug
in wings. Maybe a new set of cores with the proper tube angles would be the
easiest......and yeah, I too like bantering the aerodynamic techie stuff
(not that I'm all that qualified).

Regards,

Georgie

 

 

 

 

----- Original Message ----- 

From: Claude Weimer <mailto:cweimer at tconl.com>  

To: 'NSRCA Mailing List' <mailto:nsrca-discussion at lists.nsrca.org>  

Sent: Wednesday, October 18, 2006 10:22 PM

Subject: Re: [NSRCA-discussion] Partner set-up question

 

Hey George,

Are the dimensions you gave me what it takes to fix a Partner? Does a
Partner roll in knife edge? I thought the Partners were pretty good. I can
tell you I lowered the stab 3/8" on an Eclipse and it pushed to the gear
with left rudder and to the canopy with right rudder. Dave Guerin just
looked at the plane and said "the stab is too low" so I raised it the
diameter of the stab tube (about 7/16") and with a little adjustment it
fixed it. I don't have any mix in the airplane and it flies great. I am not
a fan of mixing problems out if you can fix it with out mixing. Any way this
experience really got me interested in these measurements. By the way how do
you go about adding dihedral to plug-in wings? Is it as difficult as I think
it is? Any way I find this kind of stuff more interesting than interrupting
the judging criteria of a figure M.

 

-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://lists.nsrca.org/pipermail/nsrca-discussion/attachments/20061020/5a42a122/attachment.html