Help! Greetings!

FieldRC

Member
Hi everyone!
Looking forward to interacting on this forum. I only recently got back into the hobby. Several years ago, I flew those terrible 2 ch toy RC planes that couldn't even turn. Eventually, I got a sport cub S which I had no idea how to use and wrecked the nose. I recently repaired it, and got some nice flights.

Unfortunately, one radial aileron servo is acting up. It's SUPER loud, jams 20% of the time, and requires trimming after a few uses. Noob question, but is that servo going bad? Is it fixable? Or should I get a new servo? I cut through the decals that held the two halves of the fuselage and verified that the servo had a problem, not the connection.

They aren't cheap, 20$ for a tiny servo. (I'm gathering stuff for a scratch build and generic/turnigy/HK servos are like 3 bucks). I have half a mind to dig out the brick and downgrade to a 3 ch build. Any suggestions are appreciated.
 

JasonK

Participation Award Recipient
repairable? sure, if you can source the parts and can manage working on something that small. but with something that small, I have my doubts on being able to repair it by hand.
 

FieldRC

Member
The gearbox feels a bit rough. On the good aileron, the gears turn smoothly, but on the bad on there's a bit of resistance. Is there anything that's a symptom of?
 

JasonK

Participation Award Recipient
The gearbox feels a bit rough. On the good aileron, the gears turn smoothly, but on the bad on there's a bit of resistance. Is there anything that's a symptom of?
yah, broken servo. could be a broken tooth, which means replacement is needed, or just dirty, which cleaning it out could work. however, given the trim gets messed up, it sounds more like a broken tooth or something that would cause a gear to slip
 

FieldRC

Member
The teeth look fine luckily. There did seem to be some crap there, which I picked off with a needle. It isn't perfect (Still messes up trim sometimes) but it's better. I'll have to see if I can clean it further.
 

FieldRC

Member
Is there a way I can remove the gears and deep wash them or something? Given how small everything is, even a tiny but of stuff can mess it all up.
 

Merv

Site Moderator
Staff member
....Any suggestions are appreciated.
Sound like you have a bad servo.

Is it repairable, maybe but probably not.

The choice to use name brand stuff or knock-offs is a personal choice. Myself I use the cheap ones, many of my friends use name brand stuff. The failure rate is about the same. They get far better service than I do, but the quality and reliability is similar. I buy servos in bulk, 10-20 at a time, for about the same price as one or two of theirs. When one of mine goes bad, I just grab another. They called the supplier and get a free one.

If you can’t fly until your part arrives, a 3 week wait is a problem.
If you are just replacing inventory, a 3 week wait is no big deal.
 

Merv

Site Moderator
Staff member
Is there a way I can remove the gears and deep wash them or something? ....
Gear can be removed and cleaned. Make sure you pay close attention to the way they come apart. After you clean them, you will need fresh grease. Don’t try to reuse the old grease, it likely has more crap in it. A light lithium grease should work.
 

FieldRC

Member
I cleaned the servo of the crap and applied a bit of grease. It's still a bit noisy, but quieter. It no longer jams and "un-trims" itself. I think it's still useable. If it burns out, I might downgrade to a 3ch design, since the sport cub S foam is getting a bit old and dinged up anyways.