REFLECTOR:Re: Aileron Rigging Frustration

[mike deeter]

Kurt:

When I did my ailerons I did the kinematics as your
Dad did and came up w/ the same conclusion.  I have
the standard wing but the same dimensions apply
except, since I assume my ailerons are less wide than
yours, I can get even less travel than you.  I was
able to get about 2 3/8" average just like you. 

After flying I find I use a small fraction of the
travel.  Admittedly, I keep things mostly straight and
level and don't do aerobatics and dramatic maneuvers
but my plane is very responsive and doesn't need huge
travel.

You can try to get exactly the same travel up and
down.....or leave it alone.....but from your data I
think you're very close to what's possible.

Mike


--- NMFlyer1@aol.com wrote:
> Well, no, I have not got the ailerons rigged
> correctly yet, and have talked 
> with Brendan a couple times. Here's the scoop:
> 
> I have the 173 Elite Model, so others may be
> different. 
> 
> I followed the plans in my manual and could not get
> 2.5" of travel (in fact 
> the maximum I could get was 2-7/16 up and 2-5/16
> down).  
> 
> I was told that there should be no differential
> aileron (more up than down). 
> 
> I ended up getting the "new" instructions off of the
> Velocity Site, and the 
> instructions are Very different. Following them
> dictated that I buy more 
> aluminum and make a new set of Cable Clamp Brackets.
> After following the 
> instructions to the letter, I could still not get
> proper travel, so I called the factory 
> again. The response was that my approach angle
> (cable to wing root bellcranks) 
> has to be off.  Well, 90 degrees is pretty easy to
> measure and believe me... 
> I have measured it at least a hundred times over the
> last few weeks. 
> 
> Finally, out of frustration (and thinking I just may
> be loosing it) I had my 
> Dad check things out. He's an Engineer at Sandia
> National Labs, and can figure 
> these things out Much faster than I would be able to
> do. He found some 
> interesting things:
> 
>  In order to get 2.5" of up and down travel (5"
> total movement), you have to 
> have 3.14" of travel in the aileron cables. Since
> the cables have only 3" of 
> travel, the maximum up/down travel possible is 4.75"
> (or 2-3/8 up & 2-3/8 
> down).   The instructions say that you can get 2.5"
> up/down travel out of a 
> properly rigged system, and that is impossible! 
> 
> This is based on some other things: 
>     1, the bell crank at the back of the Keel has a
> 4" lever arm.
>     2, the bell cranks at the wing root also have a
> 4" lever arm.
>     3, the ratio between the bell crank turning, and
> the aileron movement is 
> 1:1 (one to one)
>         I measured mine, and it is essentially 1:1.
>     4. The travel possible is based on zero slop in
> the system! It is the 
> best you will ever get. 
>     5.  Hope that my keel plate is correctly drilled
> from the factory. The 
> approach angle of the aileron cables at the keel is
> 82-degrees per side. This 
> will induce a small amount of differential in the
> system and slightly limit 
> total possible travel. 
> 
> Conclusion:   Well, after weeks of work trying to
> obtain the travel stated in 
> the instructions, I am now frustrated and
> enlightened. It is not possible!  
>    Today I will go out and try and adjust the system
> to get the maximum 
> possible with what the factory provided me:  That is
> 2-3/8 up/down travel. 
> 
> Question:  those flying the 173 Elite, is that
> sufficient? 
> 
> Possible changes:  In order to achieve more aileron
> travel, I have thought of 
> 3 possibilities:
> 
> 1,   Increase the length (lever arm) of the keel
> bellcrank by about 3/8" 
> (would get more travel and more leverage)
> 2,   Decrease the lever arm of the wing root bell
> cranks by about 3/8" would 
> get more travel at the aileron torque tube, but less
> leverage and therefore 
> stiffer ailerons). This could be done by welding the
> hole shut and drilling a 
> new one as hole edge distances could not be
> maintained by simply drilling a new 
> hole.  
> 3,   Get cables that have more travel than the 3"
> the factory provides. 
> 
> So, there is the next chapter in frustration. I will
> let you know the next 
> chapter soon. Basically I am no more nuts than I was
> before, and the limitation 
> is in the system.. not the builder.  Whew!! 
> 
> Kurt Winker
> 173 FGE ... flippin flipper fiddelin'
> 


=====
*******************************************
Mike Deeter
N2011 Test Pilot
iguanamagic@yahoo.com
http://iguanamagic.siegesmund.org
*******************************************

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