Servo Types

[Mark Hunt]

You know you're a pattern flier if:
 
(see below)
  ----- Original Message ----- 
  From: Morton 
  To: discussion at nsrca.org 
  Sent: Saturday, March 20, 2004 5:29 PM
  Subject: Re: Servo Types


  Ryan,

  Sound like a good case for a Decision Matrix, send me an e-mail and I will send a program that will analyze your choices with any variables and whatever weights you want to assign to those variables.

  Ray Morton
  jrmmorton at earthlink.net

  Ryan Wiesehan wrote:

    Hello,

    I tried to research this on my own without rehashing servo talk on the list, but I couldn't find an answer that satisfied my curiosity.  I will outline my research first so that you may better help me out.  I want to put new servos in my Used Summit III, it has 148's in it now and I think it flies great, no problem with torque, and there isn't a centering problem between days and flights.  But, I am always hearing that better servos will make you fly better.  And I want to be a better flier.  So, I have spent the last three weeks researching servos.  This research must be one of those instances when you are confused because you are paying attention.  I want is spend less than $180, $25 - $40 per servo and 40oz ok ailerons, 60oz rudder and elevator.  Here is how it breaks down in my mind from the research.  



    1.         The four basic qualifying specs for servos:  speed, torque, weight and price.

    2.         Then you have motor type and non-digital vs. digital.

    3.         Lastly, you have brand, and I've tried JR, Futaba, Hitec, TowerHobbies and Expert.  



    I am most interested in hearing your opinions about #'s 1 and 2; I don't really care to debate brand in this thread





    3-pole non-digitals; can have problems centering due to the splits in the armature.



    5-pole non-digitals; don't know there isn't really much information.  Would someone help?) I assume they have better centering and maybe more power than a 3-pole, I am thinking these might work for me so please try and sell me on the coreless. 



    Coreless non-digital; has a different armature system without poles that allows for better centering and a lighter core.  Most of the low end coreless seem like they are slower than a 3-pole.  I am starting to thing that the standard specs for speed are misleading. If the coreless motor is lighter and accelerates more quickly than a 3-pole why does a $30 coreless post the same specs as $9 el cheapo?



    Now, here is where I really get confused, change all of the above to digitals.  If the circuit board is always sending centering and position location at 3 times the rate previously to a 3-pole motor, why wouldn't I want to buy it?  It should center fine because with a digital servo centering is powered. 



    Wow, sorry, that was a long email.  I guess all that I am asking is for someone to explain why money spent on servos is valid.  Because, I just took out my plane last weekend after all this research and I couldn't figure out how it could be better. 



    Thanks,



    Ryan Wiesehan



    FreightQuote.com

    New Business Sales 






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