[NSRCA-discussion] Partner set-up question

[Rcmaster199 at aol.com]

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 
To: 'NSRCA Mailing List' 
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.
 
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