Another servo problem to ponder

[Gene Maurice]

I don’t think its gear slop seeing as how in one servo I’ve replace one the
complete gear set twice and it is now broken for the 3rd time. Ball bearings
on the output shaft are tight on the shaft and in the case. I would guess
that the ailerons are of average weight. They are large, but no more so than
a lot of designs, 3 1/2 X 2 ½ X 20.  

 

Gene Maurice

gene.maurice at comcast.net

Plano, TX

NSRCA 877

AMA 3408

 

  _____  

From: discussion-request at nsrca.org [mailto:discussion-request at nsrca.org] On
Behalf Of Del K. Rykert
Sent: Saturday, February 21, 2004 6:31 PM
To: discussion at nsrca.org
Subject: Re: Another servo problem to ponder

 

 Gene.,.. I would suspect possible slop in the gear train as possible
culprit if these aren't new servos or been in for rebuild. Do you have any
slop in your linkage or are the ailerons heavy?  You inferred you were in
the servos doing some work.. Did you check the case for wear at the shafts
points? The cases do get wore and won't hold the shaft in tight alignment
causing you to strip gears on demanding loads such as a snap. Yes flutter
and heavy surface load can also contribute but so far I don't have enough
information to jump to that conclusion.

 

                             del 
               NSRCA - 473 

    Del

 

----- Original Message ----- 

From: Gene <mailto:gene.maurice at comcast.net>  Maurice 

To: Nsrca-List <mailto:discussion at nsrca.org>  

Sent: Saturday, February 21, 2004 7:10 PM

Subject: Another servo problem to ponder

 

Please help. I have stripped aileron servo gears FOUR times. At first I
thought it was infant mortality followed by the dumb ass missed a piece of
crud in the servo case. I don’t think that’s what happened

 

Here’s the setup. The plane is an Aries, JR 8231 servos. Plane and servos
are less than four months old: about 60-70 flights. Right aileron has broken
3 times and the left has broken once (one each today). The breakage has
always been slightly right of center on the output gear. There is no static
binding. The hinge lines are sealed.  I can’t be positive but I believe the
gears are breaking during a down line snap. BTW, I snap to the right. I
don’t believe its flutter because the breakage is NOT at center. I don’t
believe its excessive travel because the breakage is not at the extremes of
travel.

 

Can the initial load of a snap place enough load on an 88 oz. servo to break
a gear? I have used this exact same servo setup in two other planes. I did
break a gear one in one of those planes. Again, I just chalked it up to
wear.

 

Confused and at a loss in Plano. 

 

Gene Maurice

gene.maurice at comcast.net

Plano, TX

NSRCA 877

AMA 3408

 

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