[NSRCA-discussion] Ackerman question

[Lance Van Nostrand]

OK, this ackerman thing got me thinking again about this and a question 
comes to light:

Many times we say that the servo arm should match the control arm to 
minimize cable slack.  However, if we use a smaller servo arm than the 
control arm I am now thinking that this does not exacerbate the cable 
tension problem. In fact, it does nothing except reduce the surface 
deflection.

If the goal is to use 100% of the servo travel (for precision) than an 
equally spaced servo/control surface would only let the servo rotate +- 
about 15 degrees for the average elevator.  This is less than 50% of the 
servo's capability.  I always used smaller arms at the servo, or use a wheel 
if I end up with too much slack.  I thought I was making the best of a bad 
situation, but now I am thinking that there is no bad situation.  If the 
clevis is on the hinge line (or the servo connection and control horn are 
equally offset in the same direction) then you should get a constant tension 
regardless of the mismatch in servo/control arms.  Is this right?

--Lance

----- Original Message ----- 
From: "Richard Lindberg" <rclindberg at comcast.net>
To: "NSRCA Mailing List" <nsrca-discussion at lists.nsrca.org>
Sent: Monday, January 15, 2007 11:32 AM
Subject: Re: [NSRCA-discussion] Pull Pull Cable Tension Question


> Here's the URL for Ackerman setups:
>
> http://members.cox.net/bdfelice/Ackerman/ackerman.htm
>
> FWIW, Bob Pastorello, et al,  discussed this on the list in November
> 2004...!
>
> Richard
>
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