Linear output

[Brian Billings]

MessageAh, a Factor fan.
  ----- Original Message ----- 
  From: Dean Pappas 
  To: discussion at nsrca.org 
  Sent: Thursday, February 10, 2005 2:41 PM
  Subject: RE: Linear output 


  Hi Jon,
  Old Dave Brown quote when someone asked him why the World Engine Expertt radios had soft sticks, if he liked stiff ones so much ... "soft sticks sell radios and stiff sticks win".
  Let's leave aside any pithy interpretations, there is a market perception issue. That, and the plastic stick assemblies don't like tons of spring tension: the old ProLinnes were made of real metal.
  Dean


  Dean Pappas 
  Sr. Design Engineer 
  Kodeos Communications 
  111 Corporate Blvd. 
  South Plainfield, N.J. 07080 
  (908) 222-7817 phone 
  (908) 222-2392 fax 
  d.pappas at kodeos.com 

    -----Original Message-----
    From: discussion-request at nsrca.org [mailto:discussion-request at nsrca.org]On Behalf Of Jon Lowe
    Sent: Thursday, February 10, 2005 1:54 PM
    To: discussion at nsrca.org
    Subject: RE: Linear output - was Notes to Self 3


     
    Yeah, but my Dad HATES expo, doesn't even use it with 3D throws!  He is such a smooth flyer, and uses fingers rather than thumbs,  that he doesn't need it, He wants control response, RIGHT NOW!  So how well his breakout force works other peoples flying is debatable.  When he was still a regular on the pattern circuit, he did spend a lot of time playing with stick lengths and tension. He also wouldn't use anything but open gimbol sticks because nothing else, at the time, felt right to him.  

    I use some expo, which drives him nuts when he flies my planes.  And my high rates are his low rates.  I tried flying with his throws, and no expo, but I'm not smooth enough to do it. We usually end up having different setups for the same airplane if we are going to trade off a lot. I run my sticks up as stiff as I can get them.  He still likes stiff springs, so at least we share that.

    I will say that virtually every new transmitter I pick up has the springs set way to soft for my tastes.  It is too easy to get unintended control inputs.  I tell budding pattern flyers (and I am one of them) to stiffen up their springs, and everyone of them has liked the feel better.  I had a Futaba 9C for awhile, and the stock springs at max tensions were still way too soft, so I bought Futaba's "heavy duty" springs, and ran them up to full stiff.  Still too soft.  If I'd kept it, I'd put on some Radio South springs.  A lady in our club, who is trying out pattern, has a low end JR computer radio.  The stock springs in that thing were even softer than the 9c, and couldn't be adjusted much stiffer.  She sent her transmitter off to Radio South and got stiff springs, and she is much happier, since she isn't getting the cross inputs. She was very frustrated before, because we could see she was putting in some unintended inputs, but she swore she wasn't.  If the manufacturers would stiffen up the springs from the factory, I think it would help almost every flyer fly better.

    Now don't tell my Dad that I questioned his tastes!  ;)


    Jon Lowe
      -----Original Message-----
      From: discussion-request at nsrca.org [mailto:discussion-request at nsrca.org] On Behalf Of Dean Pappas
      Sent: Thursday, February 10, 2005 12:20 PM
      To: discussion at nsrca.org
      Subject: RE: Linear output - was Notes to Self 3


      We don't adjust for "linear" throw:
      Some of adjust for a linear "feel", which has to be put in quotes 'cause nobody can define it, and because there are wild differences of opinion. 
      Others simply dial enough EXPO in to get manageable sensitivities arounsd neutral with the maximum throw that was found necessary to perform some maneuver.
      That usually means like the plane feels like it has a break-point in the stick response, which has always driven me, personally, nuts.

      The breakout force needed to budge the stick out of neutral is an important part of the deal.
      Jon's Dad always asserted that three ounces of breakout force were the "correct" amount. When in doubt, listen to the Guru.
      Lots of flyers dial EXPO in to solve the problem of too soft sticks, which allow them to unconsciously put undesired inputs in.
      The soft neutral reduces a problem caused by something else ... like too darned much caffeine!
      Some peoples' feel is by stick pressure, others by movement.
      You'll never come up with a one-size-fits-all deal, though Don Lowe's breakout force spec is a pretty good one.

      Later,
      Dean Pappas 
      Sr. Design Engineer 
      Kodeos Communications 
      111 Corporate Blvd. 
      South Plainfield, N.J. 07080 
      (908) 222-7817 phone 
      (908) 222-2392 fax 
      d.pappas at kodeos.com 
        -----Original Message-----
        From: discussion-request at nsrca.org [mailto:discussion-request at nsrca.org]On Behalf Of Atwood, Mark
        Sent: Thursday, February 10, 2005 1:04 PM
        To: NSRCA Discussion List (E-mail)
        Subject: Linear output - was Notes to Self 3


        Ok...I have a question for the Aeronautical engineers in the group...   All of this discussion has been centered around an assumed desire to get a linear relationship between our stick movement, and that of the control surface.  Clearly the effect of moving a control surface on the aircraft is proportional to the amount of movement...but is it linear??  I have to beleive it's not...   Just don't know the mechanics behind it...

        Assuming it's not...(And I'm betting for some portion of the throw is close enough to be considered linear and then at higher deflections it becomes either more or less efficient) is there really a purpose to trying to exact the linear nature of the stick/control surface linkage...or it is an exercise in retentiveness :)

        I also know that our spring tension on the sticks in not linear...especially around center...so it seems unlikely that what "Feels" linear isn't anyway.

        To me it's akin to comparing two high end stereo systems both of which have specifications well beyond the range of human hearing....

        -Mark

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