General brief lost of rudder control

[jmerl]

Hopefully I can get some good guidance here on this issue. 30 seconds into the flight I fly my 130x out about 100 - 150' bank it to the right to come back at me. Halfway thru the turn while the heli is sideways in reference to my vantage point, it, without any additional stick does a quick 1/4 turn as if it hit a missing tooth on the gear. I replaced both c&d gears with stock plastic gears, then one metal and one plastic.. still doing same. During this split second loss of directional control of the rudder I spend 15 seconds trying to control the heli from a crash and burn. I am getting ready to take the tail servo off and clean it. Any input?

 

[pvolcko]

Does it happen if you turn it the other direction? Have you checked the rudder servo to make sure it isn't skipping or binding at some point?

 

[jmerl]

So far seems to only do it in right turns, don't do left turns yet (still learning). How do I check servo? I can move it back in forth and seems to do fine. Is there another way?

 

[jmerl]

Ok, Just took the servo apart to clean it. Noticed one of the contact finger was bent over the other other one but still in a position to make contact. Could that be the problem?

 

[pvolcko]

Don't just move it, put some back pressure on the servo horn, linkage or blades.

Also make sure that the gears are secure on the shafts. I believe I've read of them being a bit loose, often after replacement, which can result in slipping while in flight.

 

[jmerl]

Ok so when I put pressure on the blades let say, what am I looking for (what type of movement for bad and good)?

 

[pvolcko]

You'll know it when you feel it.



If these are linear servos as opposed to the rotary, then it probably is not the issue. It is more likely contact corrosion or dirt. When you had it apart you hopefully wiped down the sliders with alcohol and put a drop or two of deoxit on there to keep them lubed and corrosion free.

What will happen if the gear/worm is stripped? When you put some mild back pressure against the movement, it will jerk or slip back a bit. If it is a gear that is stripped then it will probably cycle through to a good spot and reapply pressure until the bad spot in the gear train it hit again. Unless the stripped teeth are on a driven gear in which case it is possible for you to hold it in the right spot and it will never reassert pressure.

One other thing to check on the linear servos, make sure there aren't any cracks in the housing that the motor and gear are mounted to. MAke sure the gear and/or motor can't slip out of contact.