BLADE CP PRO HEAD WOBBLE

[DCHEEZELOG]

I just recently decided to go ahead & buy a cp pro. When i was checking it out (just out of the box) I noticed the head had & good 1/8 inch wobble in it (seen looking straight down on the main shaft). I went back to my lhs to look at another. In total i looked at 3 cp pros & 1 cp they all had that wobble. Is this common ? or did i just happen upon a bad batch?. In my opinion I would think that would cause a decent instability in flight.It is the most dificult heli I have ever flown !

any input on the subject will be apreciated & thanx in advance.

[slikrx]

Did you spin them up to full throttle?

If so, did the wobble clear up?

The wobble in a box could have several causes...

A realy simple reason is that the blades weren't at speed and had not "straightened out", but this self corrects once headspeed goes up.

The next most likely (IMHO, and I'm still a n00b) is tracking and unbalanced blades.

If the wobble persisted, or just got a little better, then the tracking & balance are more likely. tracking is the easiest to detect, since all you need to do is look.

There is a Finless video about blade tracking and many others. Go and CLICK HERE (http://www.helifreak.com/viewtopic.php?t=12455) for a bunch of vidoe "how to's". Look for "Blade tracking 101".

But, simply put, blade tracking is making sure both blades follow the exact same path. If you look at a hovering heli from the exact side, it should look like there's only 1 blade flying in a thin disk. If the blades are slightly above/below each other, they are "out of track" and will be visible. This can cause a wobble.

Blade balance is usually a lesser problem on smaller helis like the CPP, but it can have an effect. On the same page I linked above, there is a video "Blade Balancing 101" that describes how to do it. The only problem is that checking balance takes some unique tools/equipment.

Hope this helps!

Oh,and the CPP is well known for being a difficult heli to fly. I'm learining with it, and it is a handful. Having a wobble can only make thigns worse.

[DCHEEZELOG]

Thank you for the info .I have corrected the blade tracking.I didnt ballance the blades . They are way to small for the ballacer i currently have. It doesent really make any difference at full throttle .The thing i thought was odd is thet it only has a slight vibration. I am planning on getting an aluminum head anyway.Its just a little disapointing I expected tighter tolerances. If i saw that much off center movement in my 60 sized chopper i would assume somthing was bent. Thank you so much for your input . Everyone on this site has been extremly helpful in my transition to electric flight. THX

[slikrx]

I hadn't realized you were fully heli conversant (in fact, probably more so than I am :oops: )

I can get my stock CPP rotor head to be essentially "motionless".

OH! Check the flybar paddles! The can rotate pretty easily and I think can cause issues as well...

[DCHEEZELOG]

I am by no means any sort of expert . My grandfather tought me how to fly when i was a young kid .On a 90 sized chopper w/ no gyro.I purchased my 60 about 15 years ago.I have only crashed it once & that only required new blades.I did upgrade to A 70 .But then put it away. For the last 5 or 6 years i havent flown anything. I got it back out of the garage, went to the lhs for fuel & was amazed by the electric micro helis i saw. So i jumped back in head first .I realized how behind i am.The closest I have ever come to 3d is inverted flight &loops. When i was flying before mini servos cost $50 -100 . now there even smaller & cost like $17 & up. I am slowly picking it all up ,but thanx to people like you.I am learning pretty fast .I really apreciate all the help

[Murdock]

I've also noticed what I would consider to be 'quite a bit' of play in the head / main-shaft assembly. If you take a brand new retaining pin and put it into the retaining pin hole of a brand new main-shaft, you'll be surprised how loose the tolerance is. The tolerance is tighter between the pin and the head hole but that doesn't matter with the amount there is in the shaft. I was really surprised to have as much as there is in brand new parts. I check this out every time I use a new shaft and it's always the same. I've toyed with the idea of getting larger pin stock but then I'd need to make a small adjustment in the head hole.

I think this loose tolerance has alot to do with how easy it is to elongate the pin hole. If it's not tight to begin with it simply has more room to do damage in the event of a rotor strike. I've replaced main-shafts that weren't even bent but had the pin hole enlarged too much and allowed too much slop.

This is all pertaining to the Blade CPP btw.

[DCHEEZELOG]

Thanx Murdock Im glad to know its not just me .You seem to be very familiar w/ the bcpp .Do you think an aluminum head will help at all ,Or should i be looking into alternative shafts.I am asking because I have yet to take it apart and am not completly familiar with the head/ mainshaft construction/assembly

[Raysun]

Every CPPro I have had has some head wobble at spin up....the head is plastic, and sits well above the end of the mainshaft, so can't expect perfect rotation.

If your shaft is straight, spindle is straight, blades balanced ( screw them together and test on a knife edge..works fine) and blades tracked, it will fly well. It does smooth a out a lot at flight rpms.

I considered the CNC head, but decided it was not worth $150 CDN. It is a lot stronger though and will save some plastic head part repairs...blade holder arm balls snap off mostly.


Ray

[DCHEEZELOG]

Thanx for the info .It is greatly apreciated.

[Murdock]

I've thought about those cool aluminum heads too, but $135.00 U.S. will buy quite a few other parts. I am seriously considering going to an aluminum swashplate though. I've read that this can reduce 'drift' just because the aluminum swash doesn't flex the way the plastic one can. I can pick up an aluminum swash for $35.00.

I'm surprised actually at how well a heli this size does. I don't own any other heli's and this is my first experience with anything that flys RC. I'm using the stock motor and pinion with sym CF blades. The only thing I've added is another pair of flybar weights. With little to no breeze I have short stretches of hovers that I think are pretty damn stable. 5-6 feet off the ground and tail in, sometimes I can keep it in a 2 X 2 box for quite awhile. You gotta remember without training gear and with battery the thing weighs less than 11 ounces yet performs very well.

[txflyer]

the aluminum swash does help reduce drift. it was the very first "upgrade" i made to my heli. after installing it and adjusting the pitch again. it was almost night and day difference for me.

murdock- sounds like im in the same learning stages as you, and this is also my first rc heli. the flybar weights did help out when i added one to each side. try adding some self adhesive lead weights , i used 7oz weights and have about 8 of them on the nose to counter the stupid dual tail motor crap ( direct drive is in the mail ). but i noticed that the heli was alot easyer to fly. so you can remove them as you learn.

[Ben Hedrick]

The full head conversion is down to $97 now... I am thinking about trying it out.

http://www.cnchelicopter.com/servlet/the-396/%28hot%29-3dx300-HDX300-Blade/Detail

[Gino CP]

I've also encountered a wobbly plastic center hub. I've been toying with the idea of drilling small holes in 3 radial points on the hub above the retaining pin. Then using 3 allen grub screws to center the hub the way some car shift knobs do. I think the grub screws on the flybar collars or smaller will do the job.

[txflyer]

i just saw a upgraded main shaft kit on a website. it said it was for a blade cp but looked the same as a cpp. i just dont know wich blade cp upgraded parts will work for a bcpp..

neways it came with a new main shaft and pin. think it was 7 bucks i might order it. thing is it doesnt have the spur gear on the end of it, like the eflite main shaft.

[Gino CP]

Post the link, we may be able to see.

[txflyer]

http://www.freestyle-hobby.com/catalog/product_info.php?cPath=35&products_id=89

this is one i just found while trying to back track and find the first one i saw

i cannot seem to find the first upgradedmainshaft and gear i saw but have come across this. im way to tired to read it all but if you look at pilotsmith's post the 5th one down. says that it does work with the blade cp not sure about the cp pro. there seems to be some good info in there about mainshafts and all of that..

http://www.rcgroups.com/forums/showthread.php?t=527017&page=3