Rotor oscilation

[Forrest Koponen]

I am a new pilot and am trying to get my heli set up properly. My helicopter is a Honey Bee CP2. I crashed the thing right out of the box, bought new parts and put it back together. After I got the rotors tracking properly I began to spin it up. Everthing works fine until I begin to reach full throttle. The blades begin to flutter and the rotor disc oscilates. Because the insruction book is soooooo bad, I'm on my own here. What kind of adjustment do I need to do to get the thing to work properly?

[chaos]

Welcome to the wonderful world of ghost hunting. Well I don't know anything about the Honeybee but some general things come to mind. If you replaced the blades then it may be that they need to be balanced. Another maybe, maybe the blades are bolted to the blade holder too tightly. They need to be bolted on snugly, but not so tight that they can't move into their balance position. With the blades in the front/back position, they should not move in the holder if you hold the heli on its side, but if you give it a little yank they should move.

Make sure the flybar is straight.

Check the links to make sure none have stripped out the threads, allowing the pushrod to rattle around as it pleases.

Check for cracks in the blade holder. Disconnect the motor and turn the heli on and apply a little force to the blade holders to see if you can twist it to change the pitch of the blade, or if there is any slop in it. There should be no slop. The swashplate should also resist any tilting. It could be that a servo has a stripped gear.

The feathering shaft (which the blade holders mount on) could be bent. And/or the main shaft might be bent.

You might try removing the blades and spin it up... being careful not to overspeed the thing which is easy to do with no blades, and see if the problem goes away. If the problem goes away then the blades probably need to be balanced.

If you can't find anything wrong then you might have to remove the feathering shaft and roll it on something real flat to see if the shaft is bent. If the blades were broken in the wreck then often the feathering shaft gets bent. If you didn't find a problem there then check the main drive shaft.

I'm trying to picture what you mean by the blades "flutter", but that makes me think of something being broken between the pitch arm (on the blade holder) and the servo.

And I'm unclear as to what you mean by the rotor disk oscillating. If it's tilting in various directions, that also sounds like a broken connection between the pitch arm and the servo. With the power off, you might try turning the servo by hand (kinda gently) and see if you encounter a place where it seems to disconnect... as in broken gear.

It can be difficult to notice a crack in plastic, so you have to stress things a little to see.

Some manuals are crap. Let us know if you find anything, or not... somebody might come up with an idea. Likely somebody has experience with your type heli.

[hawkman]

Chaos has more than covered this subject.....so I wont try adding anything....but I would certianly suspect the blade grips being too tight....or too loose....either way they need to be equal tightness.

I was on a test flight a couple of weeks back on a real heli....a Sikorsky S61...we had fitted a new rotor head.....and we had an oscillation too....turned out one of the blade dampers was not working too well.....interesting as heck....I got to use a strobe gun doing blade tracking.

That one damper was enough to create a lateral oscillation....rc helis dont have such devices...not commonly anyway....but if one of those blades is a bit too loose...or too tight..you could easily get a wobble.

Rob

[Forrest Koponen]

Thanx for the help I've already done a few of the items you suggested. I have not checked for broken connectors. That will be next. I also read somewere about balancing the blades with electrician's tape. How about that? Another thing. After a b lade strike, some of the shrink wrap usually cracks and breaks off. Has anyone tried to cover them with something like Monocote. Thanks again, I'll let you know what I find. F

[chaos]

If you're flying with a blade that whacked something it might be that the blade is cracked where you can't see it. Suggest new blades.

[Daz(DJLFlapper)]

I am with chaos,

If your blades strick somthing during a crash and even if they dont but they are brought to a stop fast by somthing. They may well look as if they are ok but very often they can hide cracks or splits in the wood that you cant see. If you have replaced all the broken parts and are still trying to use the blades this is crazy. The blades are the most important thing on your heli, I myself replace blades whenever I crash as a point of saftey. I have had one instance of a blade that looked good when I started this hobby. I bought my heli second hand and was assured that it was in good flying condition. I could not get the heli up to speed because of blade flutter. I took the heatwrap off the blades and straight away found that one of the blades had a long split running down the glue joint up the center.
I was angry as hell but it was a good lesson to learn early on. The realisation that the thing could have come appart if the shrink wrap was not intact was scary.

I say unless you are 100% sure the blades are still good, Change them as well. you changed the other bits that were damaged. Why not change the most important bit, Afterall they took the force of a hard stop and you still got the problem with your heli.

One other thing to point out is your dampers in the head. They look like O rings. I think the CP should have them. They need to be lubed and check that they are still in good condition. The feathering shaft runs through them and the blades attach to the feathering shaft.

good luck.