N5c Head Play

[drdispatch]

Don't get excited by the title

Actually I have a tiny tiny amount of vertical play in the head with the spindle installed per the manual (greased the dampers and spindle pretty good). Is this normal on the N5c? My other models do not have this play so I'm thinking something is off. Zero lateral play and this play is very minor, 1-2 mm, just bothers me to know it's there.

[FlyawayClyde]

drdispatch, do you mean you can move the spindle axle up & down in the dampers? Or there is a gap between the grips and you can slide the spindle side to side?
As I'm sure you are aware, you should have nether.
If your main shaft is moving up and down, that is a an easy fix.
Erik

[corona007]

Most the helis I have build have some kind of washer or shim to tighten up the slop..
Maybe you overlooked it somewhere.

[drdispatch]

Main shaft is not moving. I can take each grip in my hand and sort of rock it a little. Not side to side, one grip towards the floor and one towards the ceiling. I can figure out and fix the main shaft having play or lateral play with shims - but I'm not sure what to do about this.

[corona007]

Are you putting pressure on it, If you are then it suppose to have a little give.(rubber head dampers).
But if you can shimmy the blades in the same direction of the feathering shaft, Then your missing a spacer or something not seated right.

[drdispatch]

I just took the grips off and left the dampers and axle in. Same amount of play, looks like one damper is just a tad looser than the other. I think I'm going to continue to run it and look for wobble once the motor is run in.

That's the correct thing to look for, right?

[corona007]

You should be ok, The blade grips will give a little due to the dampers. One thing you could look for though is the spacing between the head block and blade grips. They should be even.

[FlyawayClyde]

Originally Posted by drdispatch

I just took the grips off and left the dampers and axle in. Same amount of play, looks like one damper is just a tad looser than the other. I think I'm going to continue to run it and look for wobble once the motor is run in.

That's the correct thing to look for, right?

drdispatch, On my N5C the dampers came very tight and ridged. I have no play in my head. And I know this is right, I know of 2 other pilots here in my area. and I built mine as they did. You may need to get a different set of dampers.
I had a bad OWB out of the box. Other then that a fine kit. I'm saving my pennies for his next nitro machine.

Erik

[00boto]

drdispatch,

The amount of play really depends on what kind of flying you intend on doing and at what head speed.

If you plan on sport flying at lower head speeds, I would leave it exactly how it is right now. If the damping is tight you may not be able to run lower head speeds without a wobble.

If you are an aggressive flyer that plans on running 2150 on the head, you may want to tighten the damping up a bit. In order to tighten the damping, simply use one of the thinnest shims to compress the dampers and the head will be rock solid for aggressive 3D.

The dampers can vary a bit from batch to batch. The hardness specifications I place on the dampers is 90D but depending on the temperature variances in the factory as well as shrinkage after molding, the dampers can vary in hardness and actual size by a very small amount. If you are ever dissatisfied with your particular set, feel free to contact me and I will find a set specifically for your type of flying.

Thanks,

Matt

[drdispatch]

Matt,

Thank you for the reply. I'm not seeing any in flight issues with the dampers. I just heard
Todd Bennett talk about a few things which has convinced me not to obsess about getting a high head speed as I'm learning.

I have a lot of new things in this heli - the model itself, CGY 750, and my first nitro.

It appears as though I messed up the bell crank installation (first heli that's not direct to swash as well) and the flanged bearings are not fully seated in the frames and there's all kinds of play. I need to re-do this before I get to tuning the 750. I think this may explain why I get varying degrees of elev/ail cyclic each time I check with a digital gauge.