Elev. Pull pull Question

[Keith Black]

In addition to the height of the control horn we must also considered where the control horn "pivot point" is in relation to the hinge line, not where the control horn is physically located on the control surface. In other words, your control horn has a hole where the clevis connects to it. This clevis rotates in the control horn as it's pulled back and forth. If this rotation point on one elevator half is at a different point from the other elevator half then the throws will not bee the same.

Here is an EXCELLENT article on what is know as the Ackerman effect and how this applies to our pull-pull setups. For me, understanding this was instrumental in getting a real grasp on pull-pull systems.

http://members.cox.net/bdfelice/Ackerman/ackerman.htm

Keith Black
  ----- Original Message ----- 
  From: George Kennie 
  To: discussion at nsrca.org 
  Sent: Friday, November 26, 2004 11:21 AM
  Subject: Re: Elev. Pull pull Question


  Bob, 
  That sounds backward to me. If the bolt on the further traveling half is further forward, then it should be going over-center sooner generating less linear travel than the half on the other side. My bet is on the inboard hinge slot not centered (low) on that side. On mine I had some off center hinge slots. 
  Georgie 
  Daniel J. Hamlett wrote: 

      Yes 
      ----- Original Message -----
      From: Bob Pastorello
      To: discussion at nsrca.org
      Sent: Friday, November 26, 2004 9:38 AM
      Subject: Re: Elev. Pull pull Question
       Yep.  Same distance OUT from surface.  However, just checking things - again - the elevator that is travelling too far also has the control takeoff about 1/16" further FORWARD relative to the hinge line than the other half.    Could this do it? 
      Bob Pastorello 
      NSRCA 199  AMA 46373 
      rcaerobob at cox.net 
      www.rcaerobats.net   

        ----- Original Message -----
        From: Tom Hinton
        To: discussion at nsrca.org
        Sent: Friday, November 26, 2004 8:07 AM
        Subject: Re: Elev. Pull pull Question
         Are both the horns on the bottom the same distance from the surface, same amount of threads? 
          ----- Original Message -----
          From: Bob Pastorello
          To: NSRCA
          Sent: Friday, November 26, 2004 8:58 AM
          Subject: Elev. Pull pull Question
           May seem obvious, but I could use some help here....setting up my Excelleron, centers are okay, cable tensions are pretty close, centering is good.  Up elevator is fine, on Down elevator, ONE elevator moves farther, but they track together except at the endpoint, as close as I can tell. Anyone have suggestions on how I'd fine tune this out...??Hope everyone had a great T-day!! 
          Bob Pastorello 
          NSRCA 199  AMA 46373 
          rcaerobob at cox.net 
          www.rcaerobats.net  

    
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