[NSRCA-discussion] triangulation trimming

[vicenterc at comcast.net]

Hi Jerry,

>From the edge of the wing tube.

--
Vicente "Vince" Bortone

-------------- Original message -------------- 
From: Budd Engineering <jerry at buddengineering.com> 
Vicente,


When you say your CG is 3/4" ahead of the wing tube, are you referencing from the center of the tube, or from the front edge of the wing tube?  There's quite a difference between the two reference points on the Abbra due to the size of the tube.


Thx, Jerry


Budd Engineering
jerry at buddengineering.com
http://www.buddengineering.com


On Mar 22, 2008, at 6:00 AM, vicenterc at comcast.net wrote:


Chris,

What is your new CG position?  I am close to 3/4" in front of the wing tube.  In my first Abbra I was around 0.6 positive and elevator position was at 0.  In my new newer Abbras, I procrastinated and didn't install the wing adjusters.  The planes were ordered to 0.5 but they are really a little below 0.5.  I am installing wing adjusters now to increase incidence to around 0.6 and see what happen.  I expect that elevator position is going to get closer to zero as I increase the incidence.  That should reduce the amount of mixing in knife edge.  

I am not sure if you are going to be able to fix the elevator mixing.  In my old Abbra I was around 6% up both ways.  The engine was at 0.5 degree down so probably that helped.  You need to make 100% sure that the engine is NOT any amount up.  That could be a problem.  I prefer to put it small amount down to cover my error.  

I agree with you in regard tracking improvement moving the CG forward.  I got the same experience.  Another point, the Abbra rudder is very powerful.  When you check the mixing in knife just use the amount that is required to keep level fly including power setting.   

Snaps. Increasing the down elevator throw probably is going to help.  I am around 10 degrees up and 12 degrees down to get balanced feeling.  

Keep telling what is your experience in the next few flights.  I still grounded this season but I expect to start flying next weekend.  I will report on the new conditions after increasing the incidence.    

Happy holiday season to all. 

--
Vicente "Vince" Bortone
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From: Budd Engineering <jerry at buddengineering.com>
Subject: Re: [NSRCA-discussion] triangulation trimming
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