Nodding 600 NSP, help?

[robgt]

Check bearings as menioned - but how old are those dampers?
They tend to not last long anyway - lucky they're so cheap

Cheers,
Rob

[Jackflap]

Check bearings as menioned - but how old are those dampers?
They tend to not last long anyway - lucky they're so cheap

Cheers,
Rob

Rob, Heli has been flying since New Year no 3d or owt, just loops, rolls, flips, etc. I'll bang some in for what they cost. Thanks for the advice, will post Wednesday hopefully to advise how I get on.

Thanks

Shaun

[Jackflap]

Called at Fast Lads today got the bits recommended by Robgt and 3dbasher, Andy at Fast Lads advised the same so hopefully I've learned something else from this crash and my heli will stop nodding. I'll be fitting the new bits tonight and test flying tomorrow hopefully. fingers crossed. Thanks for the advise all concerned let you know how I get on.

Cheers

Shaun

[liambaker996]

lets hope it stops for the good weekend flying shaun
liam

[kamikaze]

Check that the dampers are seated properly,they sometimes don't seat fully if they are slightly out of alignment. You can usually see it because the gap between the grips and head are different either side.

[Jackflap]

Well I've replaced all bits as mentioned above and followed all the advise. When I get home tonight I'll go for a fly and see how it goes.

Cheers

Shaun

[Jackflap]

Well been down to the field today and the F'ing thing still nods as before back to the drawing board

[liambaker996]

hum that is really puzzling shaun no bent shafts could cause it ?
wiered
well hope it gets sorted soon
mate liam

[Tim Procter]

Well been down to the field today and the F'ing thing still nods as before back to the drawing board

Will get it sorted next time your here Shaun.

Bizarre it was ok before and problems now though.

We are flying tomorrow night if you fancy a run through.

[robgt]

What headspeed are you running?
How tight are the main blades?
How tight are the tail blades?
Are you sure nothing is bent - main shaft, feathering spindle, tail output shaft and tail hub?
Cheers,
Rob

[Janek]

OK, check the build sequence of your head, the description below is "low level" sorry about that, but something is being missed :

1) Headblock
2) Well greased dampers, 2 on each side, all matching
3) Feathering Spindle, also well greased when inserted (put bolts in hand tight, this will stop the grease getting into threads when you insert the spindle, remove them afterwards and clean them up)
4) Brass spacer, one on each side.

Now the grip assembly x 2:
5) Grip
6) Ball bearing into inner face
7) Ball bearing into outer face
8) Shim (this transfers the force onto the outer race of the ball bearing, therefore it's important you've got the correct part !)
9) Thrust race washer, marked "IN", with ball recess facing towards the outward facing end of the grip, this washer has the larger hole of the two washers, therefore is a loose fit on the feathering spindle, and will therefore rock backwards and forwards when on the feathering shaft (double check this), clean and re-grease this before insertion of the washer into the grip. Inspect the ball recess, it should be smooth, not pitted,
10) Thrust race, doesn't matter which way round, but should be cleaned and re-greased.
11) Thrust race washer, marker "OUT", with the ball recess facing towards the mainshaft. This washer has a smaller hole, therefore will be a tight fit on the spindle, and will NOT rock (double check this), clean and re-grease before insertion. Again inspect the ball recess, it must be smooth.

12) Inset the two grip assemblies onto the feathering spindle, carefully, so you don't dislodge the bearing assembly. The ball link arms should be Trailing.
13) Bold and washer, with blue loctite.
14) Tighten the bolts up as hard as you can with two drivers, obviously one on each end.

15) Reconnect ball links
16) Inset blades and tighten bolts equally, so they will just support the weight of the blades when the heli is held on its side.

Finally, if that is all ok, double check your head speed, I run my 600's at about 2000-2050 and get no nodding, maybe your governor isn't giving the the correct head speed, maybe because your engine in too rich and cannot produce the power to reach what you've set it at. Maybe isolate the governor, and run it on a throttle curve, deliberately ramping up the speed until the nodding stops.

I assume the blades are a matched pair ?, maybe check their balance, this is unlikely to be the problem, as it would normally lead to a vibration rather than nodding.

Let us know how you get on

[rambo0293]

How bad was the crash fella?

I see the parts what you have changed and you said that tail was ok after the crash But i have seen recently the head block where the feathering spindle goes through have a slight bend in it causing the same problem. In fact sesame on here had this very problem when you looked at it there was nothing to see but then you take i very close look against another one and you could just about see the bend. Now im not saying this is the problem but it may be worth a look as you know what tese things are like you can have a horrific crash and now much damage and then you can have very light crash and have untold amount of damage.

Good luck with your problem and keep us posted

Neil

[Jackflap]

What headspeed are you running?
How tight are the main blades?
How tight are the tail blades?
Are you sure nothing is bent - main shaft, feathering spindle, tail output shaft and tail hub?
Cheers,
Rob

Rob

N=1850, IU1 = 1950, IU2=2050 nods in all three modes in varying degrees

Tested tonight with and without governor connected

I would say my main blades are as before... hard to describe but feel stiff to move. Tail blades not stiff to move

New main shaft, feathering spindle, Tail hub looks OK and slider if free. Checked tail output shaft seems OK.

Cheers

Shaun

[robgt]

It's worth trying slackening off the main rotor blades so that they're not stiff to move.
They need to be able to lead/lag in the grips in flight.
They will hold their own weight with the right tension. Hold the heli on it's side with the blades outstretched - they shouldn't fall. A light shake (vertically ) of the heli should make them move, but not fall all the way down.

Cheers,
Rob

[Jackflap]

How bad was the crash fella?

I see the parts what you have changed and you said that tail was ok after the crash But i have seen recently the head block where the feathering spindle goes through have a slight bend in it causing the same problem. In fact sesame on here had this very problem when you looked at it there was nothing to see but then you take i very close look against another one and you could just about see the bend. Now im not saying this is the problem but it may be worth a look as you know what tese things are like you can have a horrific crash and now much damage and then you can have very light crash and have untold amount of damage.

Good luck with your problem and keep us posted

Neil

The crash.. not as bad as it could have been but broke a ball link and twisted arm on metal blade grip, usual head stuff, blades everything else looks OK. I'll check your suggestion thanks for the info. TBH I've rebuilt it three times this week I think I need a second pair of eyes to check it over just in case I've done something daft which is in the back of my mind.

Cheers Matey