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nano CP X Blade nano CP X Helicopters Information and Help


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Old 11-19-2012, 06:51 PM   #1
timox72
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Default Unexpected cause for severe wobble

Hey guys,

My Nano had a severe wobble which I couldnīt trace for some time. Changed fs, main gear, blade grips and did some more checking of the usual stuff but no luck....untill today. Made a new main shaft from some 2mm cf I had laying around and itīs rock solid.
No wobbles and no vibrations anymore, love this little Nano!!

So guys with "wobbletrouble".......check your main shafts

Thanks!

http://www.youtube.com/watch?v=yJ2Yg...ature=youtu.be
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Old 11-19-2012, 06:58 PM   #2
jbilliter
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How do you handle the little collar? How can you get it off the old shaft and on to the new?
Or do you do something else?
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Old 11-19-2012, 07:11 PM   #3
timox72
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Quote:
Originally Posted by jbilliter View Post
How do you handle the little collar? How can you get it off the old shaft and on to the new?
Or do you do something else?
Use acetone (nail polish remover) from your gf,sister, wife or mum Just put some drops on top of the collar and let it sit there for a while, later on two pliers, one you hold the ms other the collar, you twist slowly untill you hear a crack from the old ca breaking.

Put it on the new main shaft with CA, 19.05mm measured from top of the main shaft.
Honestly I wasnīt aware that such a small piece of cf could bend, thought it would just snap in a crash
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Old 11-19-2012, 07:38 PM   #4
KLR Rico
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Did this cure the transient shakes around zero pitch, or the overall vibration?

I've noticed my main shaft is slightly tweaked. It's only about 1mm off center, and causes a noticeable vibration, but doesn't seem to affect flight much.

I already have the 2mm carbon shafts that I bought for the tail boom, just wondering if it'd be worth the trouble to swap.
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Old 11-19-2012, 10:03 PM   #5
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I think the cause of my wobbles was a cracked shaft. The old one flexed quite a bit. My first attempt at making the new shaft was woefully off (0 pitch was way off). Here's what I learned.
I used acetone but still couldn't get collar off, so I found a nut that just slid over the bottom of the shaft and supported the collar I very loosely put the bottom of shaft in a vise with the nut on the top of the jaws and then lightly hammered on the top of shaft. The shaft slid down through the nut and collar.
For the new shaft I lightly sanded (400) the top of the shaft so the swash slid OK and it goes into the head OK. Dont sand the lower half of the shaft. Also I didn't CA the collar yet, but I could move it on the shaft, using pressure. Assembled the whole heli and adjusted the collar and shaft so that I had nearly 0 pitch (like it was before I took it apart). I then applied a little CA to the top of the collar.
The first flight had no wobble.
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Old 11-20-2012, 03:25 AM   #6
timox72
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Quote:
Originally Posted by KLR Rico View Post
Did this cure the transient shakes around zero pitch, or the overall vibration?

I've noticed my main shaft is slightly tweaked. It's only about 1mm off center, and causes a noticeable vibration, but doesn't seem to affect flight much.

I already have the 2mm carbon shafts that I bought for the tail boom, just wondering if it'd be worth the trouble to swap.
Fot me it was worth the trouble, for you I donīt know. one mm is quite a lot Btw it is really easy to do.
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Old 11-20-2012, 03:31 AM   #7
timox72
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Quote:
Originally Posted by jbilliter View Post
I think the cause of my wobbles was a cracked shaft. The old one flexed quite a bit. My first attempt at making the new shaft was woefully off (0 pitch was way off). Here's what I learned.
I used acetone but still couldn't get collar off, so I found a nut that just slid over the bottom of the shaft and supported the collar I very loosely put the bottom of shaft in a vise with the nut on the top of the jaws and then lightly hammered on the top of shaft. The shaft slid down through the nut and collar.
For the new shaft I lightly sanded (400) the top of the shaft so the swash slid OK and it goes into the head OK. Dont sand the lower half of the shaft. Also I didn't CA the collar yet, but I could move it on the shaft, using pressure. Assembled the whole heli and adjusted the collar and shaft so that I had nearly 0 pitch (like it was before I took it apart). I then applied a little CA to the top of the collar.
The first flight had no wobble.
Perfect I have to admit I combined the swap of the main shaft together with putting other grommets, and doubled some, on the whole set up. Whatever I do to the Nano, it will not wobble or vibrate at all.
For me worked extremely well the grommets from the FS, I have a few bend ones so I used those grommets. Hardly any play in the swash anymore
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Old 12-11-2012, 10:14 PM   #8
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Quote:
Originally Posted by timox72 View Post
Fot me it was worth the trouble, for you I donīt know. one mm is quite a lot Btw it is really easy to do.

I ended up making a new shaft. I had to lightly sand down shaft to make the swash move up/down freely, but it works like a champ now. Much smoother in flight.
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Old 12-12-2012, 02:17 AM   #9
Rustynailz
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I've twice had the wobbles on this heli because of a warped main shaft.

One question: did you have any special technique for filing down the flat parts on the shaft just right?
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Old 12-12-2012, 02:56 AM   #10
togy
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My main shaft vobbles. I've ordered a new one, but you guys seem to prefer making your owns? Are the blade stock shafts always bad or why?
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Old 12-12-2012, 06:07 AM   #11
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The nano cpx shaft does not need to be center hole punched or machined to get perfect balance.

Since all the shaft consists of is CF rod, 3 flat surfaces, and the collar pressed on/glued in place, they are easily manufactured at home with an exacto knife and some glue for pennies. Paying for an eflite shaft is a good idea as they're made on machines to exact tolerances, but if you're breaking a lot of them its better to learn on home made ones.

Some guys build custom shafts to lower the height of their rotor head as well since you want the tail motor and main rotor as close to parallel as possible given the material/weight restraints of the design.


The nano cpx shaft is a very good shaft. They rarely break if you use throttle hold and the stock weight/size blades. My MCPX had hollow shafts that snapped in one crash every time for $10 a pop and were nearly impossible to make correctly even on a drill press. Unbalanced shafts destroy rotating assembly parts such as bearings and rotor head parts. I completely sawed off one rotor head and destroyed a $15 metal hub on my MCPX with an unbalanced shaft.
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Old 12-13-2012, 07:45 AM   #12
togy
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Thank you for your answer! My question was actually meant like "are the stock shafts often not straight?". My new nano came with a slightly bent shaft which make it unflyable..
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Old 12-19-2012, 09:56 PM   #13
Ric66
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Two out of three I've purchased were bad. One came on a nano out of the box, and had the collar glued on crooked. Apparently there is enough clearance on the ID that it can be easily skewed relative to the axis of the shaft. My other nano has a near perfect shaft and collar assembly. The one that I purchased as a replacement part is worse than the OEM one with the skewed collar. The rod itself is actually not straight and it also has a skewed collar! QC is not very good in my limited sample size of three parts. I think the aftermarket could make some money on a one-piece machined part, perhaps made from hardened tool steel for durability. It wouldn't add too much weight and would probably be worth the trade off.
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Old 12-21-2012, 04:54 PM   #14
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Got the new shaft and vobbles went away:-)
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