CPP bad vibration
 

Hye guys,

I am getting my CPP back in the air after it had been sitting for a bit. When I throttle up, it is good untill about 20%. Then the heli begins to vibrate very badly, and I am forced to throttle down.

I have checked the blades- perfectly balanced.
The spindle is perfect.
When I run the motor without the blades, there is a small vibration in the head- but not much. Once I throw the blades on, it is real bad.

I think I might go to the store today and get a new main shaft and main shaft bearings. Any ideas though?

Thanks

RE: CPP bad vibration
 

Check your rotor head (i think that is what they call the part that you stick on top of the shaft and pin in place). this should have a nice tight fit with the rotor shaft, but mine has become very sloppy and causes the whole top end to wobble.

RE: CPP bad vibration
 

I want to add to what Sikorzky said if the plastic head is bent it will also wobble. I had that happen once with the mainshaft and spindle straight.

RE: CPP bad vibration
 

Thanks for your input guys. I replaced the main shaft and bearings- no change.

Is part number 008 on this page(http://www.horizonhobby.com/ProdInfo...loded_view.pdf) the one you are talking about replacing?

Thanks!

RE: CPP bad vibration
 

Yes. Are the blades tracking perfectly? Are the flybar paddles tracking perfectly and parallel to the ground?

RE: CPP bad vibration
 

I cant get the heli up to speed to tell if they are tracking properly because it is vibrating so rigorously.

When I ran the motor without the blades, the paddles tracked perfectly though.

I am going to go try to get that part tomorrow and see what happens.

Thanks

RE: CPP bad vibration
 

Do you have a pitch gauge to at least see if they are close to each other. I have had blades pretty far apart from each other without a pitch gauge and that caused really bad vibrations.

RE: CPP bad vibration
 

Yes, I do. I will check that tomorrow. Too tired now, lol.

Thanks!

RE: CPP bad vibration
 

I replaced the center hub- no good. I replaced the flybar as well as it was slightly bent. Tracking is perfect, and both blades have the same pitch.

I am at a loss. I seriously have no idea what to do.

PLEASE Help.

Thanks guys.

RE: CPP bad vibration
 

I just had that the other day and I changed out my blades after trying everthing as you did and with the new blades it solved the problem. I noticed depending on humidity and other atmospheric conditions that the blades can change shape and weight also are the blades both from the same package because I have tried to use blades from different packages like after a crash and one survives then when you put the two together they are way out of wack and you cant even check tracking the vibration is so bad. If all else is good change the blades hope this helps......[:-]

RE: CPP bad vibration
 

After school today, I will give that a shot. I am really running out of options here...

RE: CPP bad vibration
 

Flyinsolo11,

Check your blades for some torn covering,(top and bottom) that can cause some problems. But it sounds like the blades are totally out of balance or maybe warped. If you've crashed lately, check the spindle/feathering shaft to see if it's bent.

Dave / Choppersrule
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RE: CPP bad vibration
 

I agree with choppers. Bad blades can cause many problems. Also, be sure to check that the feathering shaft isn't bent. That's the 2 inch long horizontal shaft in the rotor head that the main blades pivot on. It can bend during a crash. I had a bad vibe in my machine and couldn't spin the blades fast enough to fly because it was so severe. Turned out to be the feathering shaft.

RE: CPP bad vibration
 

can you get a video?

RE: CPP bad vibration
 

Well, I feel like an idiot, lol. It ended up being the blades. I had balanced them twice to make sure they were ok- but when I swapped on new ones, the vibration completely subsided.

Thanks for your time, as well as patience. I ended up blowing 30 bucks, but you know what- it is all about the learning, right?

RE: CPP bad vibration
 

Flyinsol11,

LOL, bad blades. Don't feel bad, there's a ton of guys out there that have gone through the same headache. Glad you're back up and running. Yep, learning all the time. When trouble shooting always start with basics, it's usually the simple things we over look.

Dave
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RE: CPP bad vibration
 

Did you get the gyro to work ? Haven't had a PM from ya since I sent ya pix.

I have noticed that although blades balance, some have a bit differnent angle of attack, and the trailing edge. BTW I do not know if you gotta do this on electrics, but on my nitro I often have to re-shrink the covering on the blades.




-Mike