No fixed tips?

[Grow Pattern]

Mike,
          I don't pretend to understand why either, but that is what I was told.... :-)
  ----- Original Message ----- 
  From: Michael Lance 
  To: discussion at nsrca.org 
  Sent: Sunday, January 30, 2005 1:59 PM
  Subject: RE: No fixed tips?


  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 

    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 

      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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