Lucky escape but advice needed...

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Basically 5 minutes into a planned 6 minute flight as i was starting to come back towards the flightline to land the tail started to let go in biggish twitches (maybe 60* each time) .... i was trying to correct and it did respond but then it would go again ... did this repeatedly until i hit throttle hold.... Cyclic and pitch seemed totally responsive during this (thankfully)

I somehow managed to auto the heli from about 10ft up (first time ever done that in anger) side on and travelling to bring it to a miraculous perfect landing saving the heli ..... i'd hit throttle hold expecting a crash as i was unable to hold the tail for more than 1/2 second at a time...

VBAR log shows nothing untoward ... couple of mid-flight elevated/high vibe warnings but i guess those are from my lousy collective management during loops / flips etc ... few antenna switches but again i assume thats all normal..

Nothing in log directly before the final message of 'Gov off' which indicates me hitting TH

Rear Tail gears seem ok. Servo on bench responds ok and has torque but i need to presumably check front umbrella gears

I'm gonna rebind the Rx's but again this is purely precautionary and i don't believe will have a bearing on the issue...

What else could it be?

Model is a Fusion 50 with MKS servos all round and fullsize vbar blueline pro. Servos run off a LiFE pack ... flight packs still had almost 30% in them when i finally landed and checked

[JoeBailey]

Lucky escape but advice needed...

Over heating tail servo, I had a 9254 on my fury 55 that used to do it on hot days after 5-6 mins of flying.

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Yeah ... obv this was sunday so the heli was warm ambient 28 air temp... it was the final 20s of a 5 minute flight in which i was doing loops/flips etc... nothing major 3d by any means
.... i run an MKS 980 on the rudder which i know is rated to 6.0 ... i power it via 0.8v step-down western robotics in-line from a lifepo4 pack ... so in theory its running around 5.8v or so ...

Its on a fusion 50 so not a particularly small heli

Would the servo be ok following this? No permanent damage?

I'm going to step the voltage down further to a continuous 5.7v and maybe slow the pulse to its lower limit.

[JoeBailey]

Lucky escape but advice needed...

Being a bls servo it shouldn't overheat but that can depend on any binding on the tail. My 9254 used to do the same, start with a slow wag and get progressively worse over the course of the flight.

Only one way to find out if its any good. I used my 9254 loads of times after letting it cool down for 30 mins.

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I've taken the MKS servo off and put on my spare servo ... Savox 1290 and the heli's rock solid .... flew yesterday a couple of flights and it held beautifully ... felt even more responsive too on tail .... think a couple of tweaks still required in gain to settle it down ... although i might just drop the ball link in a hole closer so i can run higher gyro gains ... feels pretty solid but can't hurt