Loss of tail control ?

[kylelnsn]

Would suspect either a servo fault or a main board fault if you replaced the D gear.

[Jez N]

Send it back to HH and they wil fix it up for you.

[sp4rky-m4rky]

Then I guess if it's nothing mechanical (and you have re-attached the servo ball link under the tail! ) then you're back to troubleshooting the electronics.. Seems a bit of a coincidence that the tail gear was slipping. So there was obviously a mechanical aspect to it ?

If you spin the heli up whilst holding on to it (maybe remove main blades!) - do the tail respond to yaw inputs?

I would definatly try that too, I would say it is probably almost certainly not the main board. Take the blades off and spool it up and maybe disconect the push rod from the servo and operate it manually to feel and look for any binding when everything is loaded up.

[whittm]

Ok, bit the bullet, finally bought the 130x. Last week flew it for the first time outside, very impressed. Took it out again a few days later. carried out a few tentative rainbows trying to turn them in to tic toc's. Brough it in to a hover about 20 feet up and all of a sudden a flick and whistle through the air of a small plastic part, sudden tail loss, flick in to throttle hold, and even though I'm over grass, quite a solid thump when it hit. Time to inspect the damage!

All links on tail popped and a tail blade completely missing. screw is still firmly in place. Pop links back. Call shop and sort warranty, hh sending new blades, but guy at shop gets a bad back so I order online instead. Guy at midland informs me that the tail blades should not be free to rotate as I had them, or they tend to snap. Says to nip them up instead. Tonight installed tail blades, nip them up, re-bind for good measure. First flight, take off to hover and all seems fine. All of a sudden, 15-20 seconds in to flight, gracefull pirouete with 0 tail control, easy landing as it's only the tail that's affected. Try again, same thing, check all parts for loseness or stripping, no damage. So I find this thread and check the torque tube, no looseness, quite a bit of resistance between tail and head through the torque tube. Also, there is absolute and full controll of the heli for exactly 15 seconds or so, its as if the gyro for the tail control suddenly just switches off.

I am going to take it back failing any quick repairs you guys can think of. I have tested torque tube and for stripped gears. I even used switch cleaner on the rear servo and nipped up the nut on the servo. If I hold the heli down and spool it up watching the tail servo, it becomes like an on-off switch and then completely stops moving, there is no smooth control of the pitch. when i stop the rotors, it still won't move for a few seconds, and suddenly begins responding. I think the board is knackered, definately not mechanical from what you guys describe, it's not gradual loss, its instant like a switch is thrown in the heli.

[whittm]

By the way I'm a proficient mcpx'er so quite happy with little problems and repairs with those, so kind of know what to look for.

[tomatwalden]

......

I am going to take it back failing any quick repairs you guys can think of. I have tested torque tube and for stripped gears. I even used switch cleaner on the rear servo and nipped up the nut on the servo. If I hold the heli down and spool it up watching the tail servo, it becomes like an on-off switch and then completely stops moving, there is no smooth control of the pitch. when i stop the rotors, it still won't move for a few seconds, and suddenly begins responding. I think the board is knackered, definately not mechanical from what you guys describe, it's not gradual loss, its instant like a switch is thrown in the heli.

The on-off behaviour you mention is normal. All the servos are "directly controlled" and respond normally when the motor is off. Once the motor starts to spin, the flybarless AS3X unit takes over and servo movement is a function of where the FBLess unit believes the heli is oriented in space. After the motor stops, there's a 4-second pause before the gyros "release control" of the servos and you see "normal" behaviour again. Fundamentally, you can't hold the heli down then spool it up and expect to see "normal" movement of either the tail or the swash. The flybarless gyros just get confused if the heli isn't flying freely and then apply incorrect inputs to the servos.

When you say you have tested the TT for stripped gears, do you mean visual inspection? If so, that's not enough. You need to hold the main-gear still and unmoving, then try to turn the tail rotor. If should move half a turn at most - no more. If it moves beyond that, it's a pretty good chance that your "C" gear has stripped internally on the TT. Basically it has a D shape hole to lock it onto the TT - it's this internal shape that strips.

Try fitting a new C gear (one comes with the heli as a spare - almost certainly because HH know they're liable to strip!).

[sparts]

Have you checked the larger plastic gear that is on the main shaft that sits on top of the metal gear to tutrn the TT.They wear down very quickly and under load start to slip,which I think makes the heli piro.I've upgraded mine to the metal one and it's sorted it.
Also the inside stripping of the c gear can cause the same trouble,they need to bring out a Delrin cnc version.

[whittm]

Ok, not blowing my trumpet, just some info on where i am coming from. Have an engineering background, I know what you guys mean about resistance, the tail has more than enough resistance to the massive torque my fingers can produce. I have looked at the hh vid's and can see the press fit's. They are the the same as the mcpx this heli is brand new, no tail scrapes, one gentle throttle hold crash. There is no slipping under load, it happens instantly, there is full control one instant, and then 0 control, you can not move the tail one little bit!

[whittm]

Ok, this humble pie is quite chewy, and as for my hat.......

[tomatwalden]

Ok, this humble pie is quite chewy, and as for my hat.......

Have you found the problem then?

[ModelGuard.Com]

Might be worth resetting gyro gains back to default . Just in case

http://www.rcheliaddict.co.uk/e-flit...gain-menu.html

[glenflyer]

Ok, not blowing my trumpet, just some info on where i am coming from. Have an engineering background, I know what you guys mean about resistance, the tail has more than enough resistance to the massive torque my fingers can produce. I have looked at the hh vid's and can see the press fit's. They are the the same as the mcpx this heli is brand new, no tail scrapes, one gentle throttle hold crash. There is no slipping under load, it happens instantly, there is full control one instant, and then 0 control, you can not move the tail one little bit!

my 1 did the same on third flight when i moved the black wire on the servo it worked again turns out the wire is of the servo board

[whittm]

Yes found the problem - it was mechanical! Really strange, seemed almost on off sort of fault. It was the largest of the bevel gears on the tail, as you guys said the internal d shape rounded out. For future reference, I noticed people naming the gears i.e. c-gear, d-gear etc... where does this come? Which ones are which?

[tomatwalden]

Glad it fixed it. Hope your hat tasted nice ...;-)

The convential naming is the ordering of the drive.

A = bevel gear on main shaft
B = smaller gear meshing from A-gear onto TT
C = larger tail gear on TT, meshing onto ..
D = smaller tail gear on tail shaft.

Cheers. T