[SPAM] Re: No fixed tips?

[Ron Van Putte]

On Jan 30, 2005, at 1:24 PM, Rcmaster199 at aol.com wrote:

>
> I have done it both ways and notice virtually identical performance as 
> long as the aileron areas (as a percentage and planform) are 
> unchanged. What I have found stops the snap accurately and repeatably 
> is a light wing. Have not required servo pots in either type after 
> 100's of flights. Don't know why some are losing servos after a few 
> flights, but do know what works for me.
>  
> Commercial jets flying at 600 mph and models flying at 100mph, don't 
> have much in common.

Yeah.  That could also be why Indy cars are different from road race 
cars.  <VBG>

Seriously, our airplanes are in a Reynolds Number regime which is 
totally different from high speed airplanes like jet fighters and 
airliners.  Our aerobatic airplanes are even out of the Reynolds Number 
regime of full scale aerobatic airplanes, but which are are closer than 
the high speed jets.  You need to go back to the 1920s and 1930s wind 
tunnel data to get into the correct Reynolds Number regime.  
Unfortunately, researchers back then didn't (and probably couldn't) 
investigate the effects of rapid/abrupt rolls and very high angle of 
attack aerodynamics.

Ron Van Putte

> In a message dated 1/30/2005 12:30:22 PM Eastern Standard Time, 
> pattern4u at comcast.net writes:
>
> 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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