[NSRCA-discussion] Controll Systems

[Fred Huber]

There's a case where a spring tensioning system might help....

Which would be heavier?  The change to wood pushrod or the spring tensioning system putting the servo on rails and that pulley trick to take side-load off the servo output shaft?

Just what would it take to beef up the rudder hinge at the control horn to deal with the tension? (spring tension = servo rated torque to prevent slack line under flight loads)

**********

There's a trick with a spring in-line that is used in some boat steering setups (I've seen it in person-carrying runabouts)  Keeps the cables tight but allows for differential expansion of the hull vs the cables...  Not a total cure for the differential expansion load on the servo, but it would be an improvement vs the case that pulled a servo apart.  If appropriate springs could be found, it would be light.
  ----- Original Message ----- 
  From: Nat Penton 
  To: NSRCA Mailing List 
  Sent: Thursday, January 11, 2007 9:08 PM
  Subject: [NSRCA-discussion] Controll Systems


  I'm probably the originator of the .070 carbon-dep system - about 86. Carbon/balsa fuses and kevlar/balsa fuses , are poor combinations, and I'm still using them. Both systems are vulnerable to temp and/or humidity changes and are a pain. Since I've been doing this since 86 I must be a slow learner. No slop but sometimes a trim change every hour.

  With balsa fuses, for elev, I plan to go (back) to a balsa dowell pushrod and use a crossover ( MK, or custom ? ) just in front of the stab. Not sure how to handle the rudder, two small hard balsa dowells ? I've had undue kevlar tension ruin two DS8411sa servos on an electric.                              Nat


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