Servos

[Jerry Budd]

Guys, think about it.

There is very little load on that little nylon gear when used as 
designed.  Backdriving the servo by hand (which we're speculating on 
since Nat didn't SAY exactly how the servo was being used when it 
failed) exerts a tremendous load on that initial gear, far greater 
than it'll ever see in flight.

The bottom line is that the servo is just fine when used as intended 
(unless you're using the Aileron to control the motor!).

Jerry

>Nat,
>        The 9411 has this weakness. It does not matter if it is an SA 
>version or not. I run them in ailerons only. The conversion set to 
>make a 9411 into a 9411SA are 9011 gears,
>
>Unfortunately if you spin up the servo arm by hand and let it hit 
>the "stops" anywhere near firmly, it strips the little gear next to 
>the motor. The motor keeps on going and does the damage. Both the 
>metal and plastic gear sets use the same last gear, which is plastic.
>
>I have never had an in-flight failure with this servo but it treat 
>it with care when it comes to moving the controls by hand. The wing 
>bags take care of the aileron servos.
>
>What is most annoying is that this is the only Digital low-profile 
>that they market over here.
>
>The 9011's that I use do not seem to be this vulnerable. My guess is 
>that this is due to the motor types and how fast/freely they move 
>when spun up by hand.
>
>Sorry, I didn't solve the problem but I can confirm it to be the 
>servo and not just you :-)
>
>Regards,
>
>Eric.
>
>
>-----Original Message-----
>From: discussion-request at nsrca.org 
>[mailto:discussion-request at nsrca.org]On Behalf Of Nat Penton
>Sent: Tuesday, February 03, 2004 10:29 PM
>To: discussion at nsrca.org
>Subject: Servos
>
>I had two DS9411's coverted to SA . A gear , or gears, stripped in 
>both with relatively no torque by hand. They could have easily 
>crashed an airplane. Does  the stock SA have all plastic gears, or 
>only one or two ? These were converted to all plastic.


-- 
___________
Jerry Budd
mailto:jbudd at qnet.com
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