Don't Ignore That Twitchy Tail

[ripsaw]

just pulled in at the field on my way back from work

and there's John thrashing the ar*e out of his 600 in high wind, fair play for

getting straight back in the saddle after your run of bad luck mate

[Weebl]

Blimey that is some sh*t luck.

Sell the 500 as it is, and the moeny should get you a HK 500 im sure.

Yes, to me

I would wuv it and hug it and stroke it

Seriously though, that is some crap luck, nice one getting straight back on the horse and giving a heli a good spanking.

[BaRoN30s]

flippin hell, surely ya cant have any more bad luck with it.. thought it was suppose to be 3rd time LUCKY not UN-LUCKY..

I'd be prob throwing the align towel in bi nar if it was mine... lol

hope ya find out what it was at fault.

[JohnJ]

OK have just stripped the wreckage of the 500 down again, you know it's bad when you have the kitchen bin next to the table as you take it apart!

The worst part is I can't see anything wrong with the electrical system the Gyro is solid the tail servo is smooth in full travel to it's end stops and all the plugs are still in the receiver securely!

So apart from the myriad number of bits that went in the bin what do I replace next?

I guess a new tail servo will be cheaper than yet more replacement parts in the long run although I'm a dab hand at the old TT gears now

[gazza]

Have you checked all servo wires for chaffing against the frames mate?
I only had a minor nick in a tail servo wire against the carbon frame and it caused havoc. Easily missed.

[JohnJ]

Have you checked all servo wires for chaffing against the frames mate?
I only had a minor nick in a tail servo wire against the carbon frame and it caused havoc. Easily missed.

This is a fresh idea and one I will do straight away!!!!

Thanks

[JohnJ]

OK It's taken me a week and quite a lot of money but the heli is finally re-built, I replaced all the damaged parts and just for good measure I've put a new Motor, ESC & Tail Servo on it.

Guess what the darn thing is kicking about like a demented demon

The tail holds solid for a few seconds then twitches mometairily, but if I go in to Idle up it kicks around like crazy!!

I set up the 401 Gyro in Rate Mode and she was steady in the hover but in HH I have gone from 50% right up to 80% plus on the Gyro gain but it still twitches and goes bananas in Idle Up?

The only original part left is the Gyro which was working fine until recently, going to take the 750 off my other heli and try that, I even moved the Gyro from the tail support down to the lower frame to see if that would help!

I appreciate were learning all the time and despite having been flying a few years now this one has me stumped.

Any one else come across this?

John

[Gav]

what about trying without the gyro in the loop.
plug the servo directly in rx and spin it up and see if the tail servo moves - that will confirm gyro is giving you the grief or not.

and yes had similar problem with a 450 one time - GY401 was sending the tail servo nuts at a specific motor RPM. Ended up using a different gyro - never did find out exactly the cause but have the gy401 back on and it is working fine now.

good luck with it

[pgkevet]

A you know. common reasons are a wire run near another.. or the ferrite located incorrectly, or a dodgy pin in any plug..even corrosion that got move when you plugged/unplugged.. other common causes are vibration related.

Certainly support trying the servo solo but if you think its the gyro and cant find a vibe source then another simple trick is the one used with soem gyros of a meta plate sandwhiched between mount pads.. adds mass to the sensor. I solved a gasser gyro problem with a small square of roofing lead (OK alloy is traditional but I went for overkill)

And stupidly I was having a problem on my 500 that tracked down to being a loose horizintal fin causing vibes at certain RPM's

[stuskimac]

Bad luck dude, just a stab in the dark but have u tried/ fitted a step down regulator (align 5.1v, 6v - 4.8v) from the 401 to the tail servo ? might be overloading it ???

[JohnJ]

Well it seems to be sorted (Crossing The Fingers)

Last night I stripped all the wiring out and rerouted as much as possible whilst checking for chaffing.

I couldent see any damage and I know not to put power wire too close to the servo/gyro etc so quite what I changed I don't know.

Further to this I have a step down on the way for the Gyro, I've never bothered before because it worked fine but for the sake of a couple of quid I'll try anything to keep things as they should be!

I guess the only oddity now is that my Gyro gain is down to just 53% in HH Mode, anything above this and it still twitches ?

Thanks to all that have made suggestions and should anyone else have spurious tail twitches then a re-routing of the wiring could help.

Cheers

John

[pgkevet]

Well it seems to be sorted (Crossing The Fingers)


Further to this I have a step down on the way for the Gyro, I've never bothered before because it worked fine but for the sake of a couple of quid I'll try anything to keep things as they should be!

I guess the only oddity now is that my Gyro gain is down to just 53% in HH Mode, anything above this and it still twitches ?

John

I'n guessing your new tail servo is just working better/too sensitive. The stepdown will probably slow it anyway ,but you might just experiment with moving the ball in a little..

[JohnJ]

OK It's midnight and I've finally tracked down my tail vibration problems

Tonight I spent five hours stripping one part at a time and finally found the Tail Rotor arm to be the problem, yep the Grub screw had Loctite added and was secure but very slightly out of kilter!

I found this by repeatedly spinning the head by hand as I took various parts off the heli in order to track down the vibration I could feel as it spun, the problem was totally invisible to the naked eye!

Will take the heli out in the morning and try to set it all up again

[pgkevet]

You see? You wouldn't have any of this trouble if you stopped bending your toys!

[JohnJ]

You see? You wouldn't have any of this trouble if you stopped bending your toys!

There's been several occasions where this heli nearly went into orbit without a lipo installed!

Numerous people have kindly posted worthy suggestions and I did follow up on most of them but of course it dident cure the odd tail vibration, I replaced almost the whole darn heli chasing the cause of this vibe and if it isnt sorted now the "Look Out"