flying yesterday with my carden extra 50cc. walled it into a hover and one elevator servo locked to full up. i fought it to the ground with minimal damage. went to pick it up and seen the servo went past its stopping point and flipped to the other side just enough to lock. savox 2270. it should have had enough torque to hold its spot. nothing is stripped or out of place. i tore down the servo and its fine. could i have browned out long enough to have the servo lose its power? im confused on this. the pushrod at full deflection was kinda straight. maybe i need a longer arm and less travel?

had this happen using Looong arms, extreme travel and alot of surface back pressure.
whats happening is, and I'm going to assume you have a setup with long servo arms and travel set to its maximum on that servo...

when you walled with full up, your arm was pushed back the wrong direction by extreme air pressure on that elevator half, and the servo mechanically could not fight that sort of leverage.

reduce the amount of travel on your elevator servo's and use longer arms if you need to.
you might end up having to reduce the amount of throw if you can't find a mechanical solution.

also you can try using a lower hole on your elevator horns.

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The servo didn't slip. I have the recommended 1.5" arms. The horn on the surface is the screw type and can't go lower. I might have to try the longer arm and less travel just to make more of an angle on the rods. Right now the rod gets almost straight at full deflection. I don't fly hard enough to hopefully have servo issues. It might be the setup even though it is by the manual. Thanks for the thoughts so far

any other ideas? i got my longer arms today but dont know if itll help or not. this issue has me worried about losing a expensive plane

almost sounds like you had just enuff blow back to force the arm the other way thus causing your malfunction. I would change out the servo as well,,, why? because it probably got real hot trying to go back the other way in the jammed up position. Fresh servos are cheap insurance

Originally Posted by nappyroots2182

The servo didn't slip. I have the recommended 1.5" arms. The horn on the surface is the screw type and can't go lower. I might have to try the longer arm and less travel just to make more of an angle on the rods. Right now the rod gets almost straight at full deflection. I don't fly hard enough to hopefully have servo issues. It might be the setup even though it is by the manual. Thanks for the thoughts so far

I think you need to move the horn out away from the surface, the lower or closer to the surface the farther and faster it will move

I have longer servo arms I can install and yes I was thinking of moving the control horn out to keep the same travel if possible. Also thought about making some sort of arm stop to keep from doing this again....hmmmm. servo want buzzing when I picked up the plane. Maybe it thermal shut down? It acts and works fine.

>>> Maybe it thermal shut down? It acts and works fine. <<<

While it may look "Mechanically OK" there's no telling what damage it did Electrically at max amperage trying to right itself.

The price of a new or a known good servo is far less than the cost of a totally new plane

Using longer servo arms will only exacerbate the problem...347oz of torque at one inch with 6 volts should be more than enough torque for any 50 cc plane...sounds like you have a dud servo or your arm is way too long.

https://www.flyinggiants.com/forums/...82&postcount=9

Futaba had a issue a few years ago with a couple models of servos. Once beyond a certain limit they would get confused and try to keep going that direction to get back to neutral. Then they hit the mechanical stop and or travel limits and you were hosed..

I don't think this was a servo issue. When at full deflection my linkage was almost straight. I think some blow back could of moved the servo to the other side of its travel and locked. The real question is how to get a better geo on my linkage? That's why I thought a longer arm and less needed throw would help.

Nappy, the linkage geometry on your plane's elevator is what it is. Not saying that its wrong but its not really right either largely in part of todays servo rotating servo arm and gear train design. So, if your going to use that bigger servo arm, your gonna need a bigger torque producing servo or just install a bigger torque producing servo to over come the blow back issues or what I call,,, aerodynamic deficiencies.
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Here's another way of looking at it,,, if your gonna operate something at 100% all the time, how long do you expect it to last? So again your requirement is for a bigger and better quality servo.

Way back in the day, Kraft Radio design engineers had the right idea for servo linkage geometry with one of these,,,

well whats a good servo that might help? i guess ill reduce throws and leave the arms im using on there now. i figured 444oz would of been more then enough. the only 3d i do is walls and torque rolls. i get what ur saying. im just frustrated now as i cant afford anymore stuff for this plane. thanks for the help guys

would love to see a picture of the linkage setup