No fixed tips?

[Michael Lance]

Eric,
 
I would think that the high pressure dumping from under the aileron (and
the resulting vortices) might help start the snap.  I don't understand
how having the aileron all the way to a flat plate wingtip helps with
stopping the snap.
 
What's the theory?
 
Thanks,
 
Mike Lance
 
-----Original Message-----
From: discussion-request at nsrca.org [mailto:discussion-request at nsrca.org]
On Behalf Of Grow Pattern
Sent: Sunday, January 30, 2005 9:30 AM
To: discussion at nsrca.org
Subject: Re: No fixed tips?
 
The current theory is that the ailerons all the way out to the tips,
stop the snap more accurately.
 
Eric.
----- Original Message ----- 
From: Bill Glaze <mailto:billglaze at triad.rr.com>  
To: discussion at nsrca.org 
Sent: Sunday, January 30, 2005 11:33 AM
Subject: Re: No fixed tips?
 
Again, with the full-size:  Notice that such luminaries as Boeing,
Douglas, et.al don't run their ailerons to the tips, but instead stop
short?    As Troy and Doug have stated, the wingtip vortices generated
are the reason.  I had a long discussion with Dick Hanson about this,
and he stated that "it didn't make any difference on our models."  Well,
from what Troy has discovered about aileron pots, it seems it DOES make
a difference.
Bill Glaze

Troy A. Newman wrote:


They don't fly the same....and the aileron thru the tip thing wears out
servo pots faster. I flew a model this past summer and it went thru
aileron servo pots in 50 flights. I normally get well over 100-125
flights. And this was a wood model so the vibration was better damped
than a composite fuse.
 
Wing tips have lots of turbulence coming off of them...then stick a
aileron in this turbulence. NOPE not the best from an engineering
standpoint. 
 
The answer guys and manufacturers give is it snaps better. My answer is
design a good wing and it will snap better. Copy a good wing and it will
snap better.  The ailerons become more effective with the area at the
tip....but I don't feel it helps flight performance. Aileron thru the
tip is much easier and faster to build than a boxed in version. on the
ARFy stuff its cheaper...this is the biggest reason I think its done.
 
As for elevators without tips there are no references. And the same
things apply
 
All my models have them boxed and will have them boxed in.
 
Troy
----- Original Message ----- 
From: Tim Taylor <mailto:twtaylor at ftc-i.net>  
To: discussion at nsrca.org 
Sent: Saturday, January 29, 2005 7:46 AM
Subject: No fixed tips?
 
No fixed tips at the end of the wing/stab seems to be the rage. Any real
reason for this? I really don't care for this very much as it makes it
harder to make sure your trim is right and the elev half's meet.
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