CPP Nose / Tail SeeSawing

[Murdock]

Ok this just started this morning...funny how everything 'just starts'...
Anyway the nose and tail are see sawing up and down...maybe as much as an inch or two and quickly, almost twitchy but consistently. Seems almost 'shakey'.

Any ideas?

[Buzzkill]

Check your dampers. They may be too tight or worn out. Could be too many shims.

[Murdock]

Hey Buzzkill thanks. I just rebuilt my entire grip assembly and have noticed that there is clear space between the O rings and the last step washer. I even put 2 shims on each side to no avail. Should the O rings be totally depressed down into the hub or should they stick out a bit? With the O rings all the way into the hub it would take 8-10 shims to clear up all the empty space in there. This is all assembled per the exploded view in the manual.

Thanks

[Buzzkill]

Wow thats a lot of space between the o -rings and the step washer. Usualy the see-sawing is caused by tightness.

[Gino CP]

Sounds like low head speed. Check if tiewraps are rubbing on main gear. Replace motor. Set pitch to zero in idle up. Make sure servos are are horizontal or 90deg in idle up. Of course pull both motor connectors when doing this. make sure rotor head is centered in the center hub by adjusting servo links while keeping swashplate level.

Are you using EFlite recommended pinion/blade/battery combination?

[Buzzkill]

Forgot about low head speed.I overlook the obvious sometimes :arggg:

[Murdock]

Well being a noob I think I've discovered at least the problem with the space between the O ring and the washer. I was manually forcing the O ring all the way into it's circular cut-out in the hub, after pushing the spindle through. In retrospect, I have no idea why I did this except that I knew no better. In retrospect, after re-assembly without stuffing the O ring into the hub and just stacking all parts in order on the spindle without grips, it becomes obvious to me that under normal operation ( due to centrifical (sp) force ) the O rings would never be forced into the hub all the way. Due to that force they would always be pushed outward. Now, still without grips, there is no slop or space BUT there is O ring to do it's dampening job.

Is my thinking here sound so far?

[Gino CP]

Shove the orings into there cavities. That's what it's for. This allows good traclkking. Don't mind the gap. Blades will always be pulled apart and there will be no inward force. Well, technically centripetal force goes inward. But that won't be moving the blade grips inward.

[Rebuild]

Just don't run it too loose though..you will start taking out your tail boom/booms! The tighter you run the see-saw at "O" rings the faster you will have to spin the head to avoid that rocking you are describing. :shock:

[Buzzkill]

Wow thanks rebuild. I replaced the o rings with bearings (experimenting) and got the tail/nose wobbles. I may try again with 10t or 12t pinion.

[Rebuild]

Yeah, Buzz! That will need a rip'n headspeed. I would guess approaching 3000..2700/2800 may do. :WOW

Edit: Also, with a head that tight you have to have perfect tracking too!

[joehelicopter]

Try this...I run 2 sets of o rings in my CPP-
no wobble and it really cuts down the boom strikes.

[Rebuild]

That's a good idea there, joehelicopter..I'll give that a try next time I have this thing of mine torn apart. :idea: