garyparnell

More help needed please!!!!!
I have rebuilt my CP Pro after a basicly mild crash, and now it has developed a serious vibration at mid throttle. I have replaced the main gear and shaft. blade holders, cross shaft, flybar, and practially everything else that could cause a vibration. My blades are weighed on a digital scale that goes to a tenth of a gram and they weigh in the same. Any ideas?????

orlbuzz

gustboy,

make sure all your step-washers and shims, if you have any, are correct on your spindle. Is flybar centered? Is it the tail rotor? Is it balanced. Are the cg's of the blades equal? Make sure the flybar is threaded into each paddle an equal number of threads. If all else fails, try balancing the complete head assy., flybar with paddles and blades as a complete assy. You can remove the motor and let it balace in the bearings.

I hope you find it.

orlbuzz

Kerberos32

Are you using carbon fiber blades? I have a pretty serious head shake much like you describe when using the CF blades. I've tried three different sets, and they all have have same behavior. Seems like some kind of vibration harmonic. All the blades are the exactly the same weight, so I have no idea what could be causing this. If I put the wooden blades back on, its vibration free.

Dynamic

Could be a bent spindle.

garyparnell

Thanks for the replys. I am using plastiblades, and wooden ones. (both flat bottoms) they both shake violently. I can pretty much rule out tail rotor vibs, as I have it disconnected for testing the main rotor. Can anyone comment on just how closely the blades should match in weight? I have a scale that goes to a tenth of a gram, is this close enough???

jblanch

Try changing the blades from one side to the other (blade 1 to blade 2 position and blade 2 to blade 1 position) once I had that problem and I solved it changing the blades... and balance with small pieces of transparent tape (the one used by USPS works great). Hope I can help you with this hints!!!

Good Luck

Tito

Heli_Harry

It sounds like you have a bent spindle to me as well.

Have you tried pulling it out and rolling it over a flat surface (sheet of plate glass works well) to check it.

I have heard f them being bent even when new (bent in shipping?).

I would look there first.

As for blade balancing pull your blades out stick something thin in the holes (jewelers screwdriver) and balance.

zdsh13

It sounds like a bent spindle to me as well, what I have done is remove the top rotor head so just the spindle is in place and run up the motor, watch the spindle from the top and see if it is centered. If not lightly bend it into position until it is, I have never removed my shaft to straighten it, I have always done it in place. You won't get it perfect but its generally good enough with almost no vibration. After about 5 - 10 bends I needed to change the shaft as it was getting harder to straighten. Good luck

jakjr

My Feedback: (18)

Have you checked the blade tracking yet?

garyparnell

Thank's to you all for your input on this problem. I have gone back through my work and I think I have found an answer. The blade tracking was indeed off, but I really didn't think that it would cause such a vibration that I had at a somewhat slow head speed. After setting the tracking a little closer the vibration seems to be a lot less, but not all gone. I am heading out to the LHS for spare parts, and I will reset the tracking when I return. Again, Thanks so much for the help.

OttoNP

I agree, it sounds like a bent mainshaft or spindle. Try spinning it up litely with no blades on it, you can see easily if the main shaft is bent. Don't speed it up too much though

///mpower

I just managed to develop the same thing with my blade cpp, but it is an all rpm vibration. No crash or anything....i'll have to check the spindle, but there is no reason for it to be bent...no crash or harsh landing...just went for a flight and it was vibrating.

FMB42

The spindles on these bend pretty easy and only cost about $5. They are also quick and easy to change.

Georges Payne

How much vibration is too much vibration anyway? I tried everything I could to eliminate all the vibration in my Blade CP Pro. But it is impossible.

I straightened the flybar shaft, the spindle, and the mainshaft, until they can roll down a very shallow incline (about 1 degree, maybe) on a sheet of glass, all by themselves without the need to get them going.
I made a blade balancer based on the same principle as a prop balancer, by bolting both blades one opposite the other and perpendicular to an axel, and the blades come out with exactly the same CG and weight, to the millimeter, and I can improve the balance of new blade sets that way.
I balanced the rotor head with the flybar and paddle in place, until it stays in the position i put it in,
I adjusted blade tracking to within half the blade thickness at 75% throttle, and the angle of attack is OK too,

and I still have a wobble.

Two things I'm not sure about :
How to make sure that the paddles track perfectly? The pitch gauge is too akward for that task, I have to rely on my eyeballs;
I don't know how to make sure that the spindle doesn't have too much play in the hub. Maybe the o-rings are worn? Maybe the spindle has become slightly longer by being bent and bent back to alignment, and I would need to add a few shims?

Any help would be appreciated.
Georges

Edited for typos

rcmiket

Funny a friend picked up a CP Pro flew it a few times busted a few parts. ( We all picked up CX2's figure we had this heli crap figured out he moved up we watched). He was having issues and getting frustrated. I was ready to by one( heck I can do this). A good friend shows up at the warehouse( our windy day flying field) with a T Rex friend fly it jumps online buys one and I end up with his CP Pro 2 batteries plastic blades and a few extras. Took it home home to look for the "vibration" figured it was the spindle turn out one of the pitch control links was bent made the repairs checked all the online info I could find and its flying great( just hovering right now but I have no doubt this is going to be a great deal. Everything I've read says this CP Pro is hard to fly etc. Ithink the problem is guys just don't want to get into the mechanics of these things to bad for the money its a pretty good deal.( but I'm looking real hard at a T REX). Figured this might help some guy pulling his hair out over this. Oh yea I paid 200bucks for his CP PRO

garyparnell

Back again, and sorry to say that I had to part with my CPP. I did find the main cause of the vibration. In my quest to set up my rotor as slop free as possible
I had the spindle set up too tight. Think about it, those orings that the spindle ride in are there for a special reason. The orings act as a simple damper for minor vibrations. If you add too mant shims to take up slack you can get it a bit tight and eliminate the damping ability of the orings. Look at the hole that the spindle goes through. You will find that it is oblong up and down, and slightly larger in diameter. This allows the spindle just enough freedom to transfer any slight vibs to the orings. I must say that I had a blast with this copter, but I just could not justify the maintenance expense verses the grins. The lord givith, the Blade CP pro handily tooketh too much away. I learned a lot, and if I get back to helis I will step up to a Trex.

budpro

I will soon purchase a CP Pro...this site gives me lots of knowledge, and problems are answered well before the purchase....I entered the words : Blade CP Pro vibration in the search box upper left after I read your post.. one guy stated that blades were too tight, so that answered his vibration problem. Check it out dude..maybe it's your problem too...
Fly High, Be Safe!!!!