Nodding 600 NSP, help?

[Jackflap]

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

Tim's advised they maybe flying tomorrow, and suggested I take a ride up. That's an offer I can't refuse, a chance of a second opinion could find what I can't. Cause I'll be F'ed if I can see it. My missus thinks I'm pulling a fast one for a 700 I think

[Jackflap]

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

Tim, Caroline's got the flapjack in the oven already, ring you tomorrow.

[rambo0293]

Thats what happened to sesame's when he bent the block the blade holder ball link come off and twisted the arm and once rebuilt had the same problem so it could well be that.

Neil

[Jackflap]

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

JaneK

Firstly thanks for taking the time to detail the basics above (top man) I'm going to print them off for future use

Secondly I agree with you something is being missed but what . I've had some more suggestions tonight to check which I will do tomorrow. This is my first crash / rebuild on a 50 so could be missing something a more experienced flyer / rebuilder would spot straight away. Shame we didn't have teleporters like Star Trek I could have beemed you all up for some beers and something to eat and I'd probably have a nod free heli by now.

Thank you for your time, once I find out what I've done wrong I'll let you know.

Cheers

Shaun

[Jackflap]

Quick update

Called at Fast Lads today to get a second look. On closer inspection we found a bit of movement on the head where it bolts to the main shaft (even when Jesus bolt tight). I bought a head just in case for what it cost. It was recommended that I also change the main shaft bearings, Andy thought there was some play in them.

So I've done suggestions in previous posts rechecked blade grip area and set blades as advised (thank you all who contributed) the new head fitted the main shaft a lot better and now have no movement in that area. The top two main shaft bearings did need replacing. The top one is that bad it locks in numerous places. All three changed.

See what tomorrow brings

[Tim Procter]

Fingers crossed for you Shaun hoping it gets sorted soon.

As you said you are busy this weekend but if you find time you know where we are.

Only too happy to swap out parts to locate the problem for you.



PS: gazza and Paul were flying here tonight, Flew like real men again I'm happy to say.

Roll on weekend.

[Jackflap]

Looks like we have success

Well I finally got out flying this evening after too long a break. The heli seems to be back on form again given it a thrashing round the sky's and all seems well Hopefully this weekend should be good to give it a real thrashing

I'd just like to say thank you to all who passed on their advice on my thread for help. The amount I learned from this experience has been considerable without the help given who knows where I'd have been now. A thank you to Fast Lads for their help too.

Cheers Shaun

[gazza]

Well I finally got out flying this evening after too long a break. The heli seems to be back on form again given it a thrashing round the sky's and all seems well Hopefully this weekend should be good to give it a real thrashing

I'd just like to say thank you to all who passed on their advice on my thread for help. The amount I learned from this experience has been considerable without the help given who knows where I'd have been now. A thank you to Fast Lads for their help too.

Cheers Shaun

really chuffed for you shaun
What was it? The head block? My 500 is doing the same so I'm scratching my nut at the moment too.

[Jackflap]

really chuffed for you shaun
What was it? The head block? My 500 is doing the same so I'm scratching my nut at the moment too.

Gazza,

That's all I can think it was I changed the bits main shaft bearings and head block and seems OK. I was advised to put some thread lock on top of the main shaft as well when fitting the head block which I did. I also followed advice given earlier in thread as well. For what the bits cost £5.81 for the bearings, and just over £23.00 for the block I did it anyway. Being my only crash rebuild not sure if I did something wrong on the rebuild as well??? I'll see how this goes and may try the old head block again to see if there is any difference later.

Cheers Shaun