help needed, losing tail servo at midstick

[trexamanic]

i have checked all the wiring and dont see anything wrong. i do my pre flight checks and when i get up to hover i lose tail inputs altogether. i have held it in my hand and tried the same tests. i have proper input on rudder but once i spool up it disappears??
anyone know whats going on?
help appreciated

[tonystevens]

stripped gear somewhere?

[Nick B]

Servo is dieing,i had the same,time to go DS35

[stevek32]

when you say no tail input what do you mean?, i.e pyros in the air, or just no rudder movement?.

the 130x avcs system works slightly diff in the it switches between hh and rate depending on if the motor is running or not,

[trexamanic]

when you say no tail input what do you mean?, i.e pyros in the air, or just no rudder movement?.

the 130x avcs system works slightly diff in the it switches between hh and rate depending on if the motor is running or not,

i am only hovering and the tail input stops. i havnt flicked it into IU 1 so wonder if this is anything to do with it??

i cant see any stripped gears. tail blades still going full tilt but the rudder input just stops

[stevek32]

iu 1 shouldnt make a diff tbh, try disconecting the motor and put throttle to halfway point and try the rudder this will trick it into thinking you are at hovering so will go into rate mode,
if rudder seems still to work ok it may be as said above tail cyclic on its way out, another way to test is to unplug tail cyclic from main board and plug it into an ail plug (they are colour marked plgs so you wont get them mixed) anyway try that spool up holding heli CAREFULLY or tape it down and see if tail cyclic now ail responds to stick if yes all good if not it will tell you its on its way out.

[stevek32]

if its is on its way out you can revive them by cleaning them
here

Blade mCPx Servo Cleaning - YouTube

same servo just smaller, they have got fine finger strips that contact the board these can bend slightly therefor lose contact with the board just bend them very slightly back towards board and job done,

[trexamanic]

ok guys thank you, i will try the suggestions.

[Three6ty]

I might be barking up the wrong tree here, but today on my second flight mine would take off then start piroing out of control. I to thought the tail servo was dead. Took a while to figure out but we eventually discovered that the tail boom had moved out a few mm in a previous flight after a little crash. The torque tube was engaging but not quite enough and once spooled up did not engage properly with the tale blades. Once we noticed, we loosened a few screws, popped it back in the few mm and all was good again.

[stevek32]

Yep they forever strip out center of tail gears and yep the boom does slip. I use thread lock on most parts now upgraded to Metal tail cogs now so at least that cuts out the stripped inner cog.

[cjcj1949]

I couldn't understand Nick B's comment. He's had a similar fault and fixed it. The only thing that makes sense is that the servo can't provide enough force to move the tail blades once they are turning. You could prove this by disconnecting the motor and see if the servo now works at half throttle. I'd change the servo. You'll probably need a spare anyway.

[Nick B]

I couldn't understand Nick B's comment. He's had a similar fault and fixed it. The only thing that makes sense is that the servo can't provide enough force to move the tail blades once they are turning. You could prove this by disconnecting the motor and see if the servo now works at half throttle. I'd change the servo. You'll probably need a spare anyway.

To elaborate,the servo just dies and then comes back,then dies and so on,the problem lies at the servos centre,an area that gets the most use.

I had it with a cyclic servo too,the heli would just roll and crash.

[Delarado]

Stripped tail gear.

I had exactly the same thing happening on mine. It was the gear at the back of the torque tube.

It often just about has enough "bite" to stop it piro'ing out of control, but youll find it "weather vanes" with the wind.

Could be the servo, but id check the tail gear first, thats what my moneys on.

[Nick B]

i have held it in my hand and tried the same tests. i have proper input on rudder but once i spool up it disappears??

From that i read it that when you spooled up in the hand the tail blade pitch slider stops all together because the servo stops?

[cjcj1949]

Standard fault finding is to replace the bit that's most likely to have failed. I don't see NickB's argument about the centre bit being worn out for this fault as it's ok until spool up. It seems load related, so boom movement or gear wear. Being logical doesn't always work with faults though, changing things at least eliminates something. At least you have a definite fault, not one that comes and goes.