Unexpected cause for severe wobble - HeliFreak
Fun, Learning, Friendship and Mutual Respect START  HERE


Unregistered
Go Back   HeliFreak > R/C Helicopter Support > Blade Helicopters (eFlite) > nano CP X


nano CP X Blade nano CP X Helicopters Information and Help


Reply
 
LinkBack Thread Tools Display Modes
Old 11-19-2012, 05:51 PM   #1 (permalink)
Registered Users
 
Posts: 431
 

Join Date: Dec 2011
Location: Spain, Las Palmas
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!

Blade Nano CPX bend cf main shaft (0 min 18 sec)
timox72 is offline        Reply With Quote Quick reply to this message
Sponsored Links
Advertisement
 
Old 11-19-2012, 05:58 PM   #2 (permalink)
Registered Users
 

Join Date: Feb 2012
Location: Columbus, OH
Default

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?
__________________
NCPx+ Mild BL, MCPx, EXI 450pro FBL ZYX-S2, HK250GT DFC ZYX-S2, T-Rex 250 DFC ZYX-S2, MSR, DX6i
jbilliter is offline        Reply With Quote Quick reply to this message
Old 11-19-2012, 06:11 PM   #3 (permalink)
Registered Users
 
Posts: 431
Thread Starter Thread Starter
 

Join Date: Dec 2011
Location: Spain, Las Palmas
Default

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
timox72 is offline        Reply With Quote Quick reply to this message
Old 11-19-2012, 06:38 PM   #4 (permalink)
Registered Users
 

Join Date: Oct 2012
Location: Spokane, WA
Default

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.
KLR Rico is offline        Reply With Quote Quick reply to this message
Old 11-19-2012, 09:03 PM   #5 (permalink)
Registered Users
 

Join Date: Feb 2012
Location: Columbus, OH
Default

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.
__________________
NCPx+ Mild BL, MCPx, EXI 450pro FBL ZYX-S2, HK250GT DFC ZYX-S2, T-Rex 250 DFC ZYX-S2, MSR, DX6i
jbilliter is offline        Reply With Quote Quick reply to this message
Old 11-20-2012, 02:25 AM   #6 (permalink)
Registered Users
 
Posts: 431
Thread Starter Thread Starter
 

Join Date: Dec 2011
Location: Spain, Las Palmas
Default

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.
timox72 is offline        Reply With Quote Quick reply to this message
Old 11-20-2012, 02:31 AM   #7 (permalink)
Registered Users
 
Posts: 431
Thread Starter Thread Starter
 

Join Date: Dec 2011
Location: Spain, Las Palmas
Default

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
Hereīs a pic:
Attached Thumbnails
Click image for larger version

Name:	DSC_0010.jpg
Views:	128
Size:	50.5 KB
ID:	367611  
timox72 is offline        Reply With Quote Quick reply to this message
Old 12-11-2012, 09:14 PM   #8 (permalink)
Registered Users
 

Join Date: Oct 2012
Location: Spokane, WA
Default

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.
KLR Rico is offline        Reply With Quote Quick reply to this message
Old 12-12-2012, 01:17 AM   #9 (permalink)
Registered Users
 
Posts: 167
 

Join Date: May 2011
Location: Alberta, Canada
Default

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?
__________________
Russ
Rustynailz is offline        Reply With Quote Quick reply to this message
Old 12-12-2012, 01:56 AM   #10 (permalink)
Registered Users
 
Posts: 596
 

Join Date: Feb 2012
Location: Sweden
Default

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?
__________________
-—-—
GAUI X5, Align 450PRO, Blade NCPX
togy is offline        Reply With Quote Quick reply to this message
Old 12-12-2012, 05:07 AM   #11 (permalink)
Registered Users
 

Join Date: May 2012
Location: Indy
Default

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.
tchilds is offline        Reply With Quote Quick reply to this message
Old 12-13-2012, 06:45 AM   #12 (permalink)
Registered Users
 
Posts: 596
 

Join Date: Feb 2012
Location: Sweden
Default

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..
__________________
-—-—
GAUI X5, Align 450PRO, Blade NCPX
togy is offline        Reply With Quote Quick reply to this message
Old 12-19-2012, 08:56 PM   #13 (permalink)
Registered Users
 

Join Date: Jun 2011
Location: Yorktown, VA
Default

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.
Ric66 is offline        Reply With Quote Quick reply to this message
Old 12-21-2012, 03:54 PM   #14 (permalink)
Registered Users
 
Posts: 596
 

Join Date: Feb 2012
Location: Sweden
Default

Got the new shaft and vobbles went away:-)
__________________
-—-—
GAUI X5, Align 450PRO, Blade NCPX
togy is offline        Reply With Quote Quick reply to this message
Reply




Quick Reply
Message:
Options

Register Now

In order to be able to post messages on the HeliFreak forums, you must first register.
Please enter your desired user name, your REAL and WORKING email address and other required details in the form below.
User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.
Password:
Confirm Password:
Email Address
Please enter a valid email address for yourself. Use a real email address or you will not be granted access to the site. Thank you.
Email Address:
Location
Where do you live? ie: Country, State, City or General Geographic Location please.
Name and Lastname
Enter name and last name here. (This information is not shown to the general public. Optional)
Helicopter #1
Enter Helicopter #1 type and equipment.
Insurance
Please select your insurance company (Optional)
Helicopter #2
Enter Helicopter #2 type and equipment.
Helicopter #3
Enter Helicopter #3 type and equipment.
Helicopter #4
Enter Helicopter #4 type and equipment.

Log-in

Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.



Thread Tools
Display Modes

Posting Rules
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On




Copyright © VerticalScope Inc. All rights reserved.
 

SEO by vBSEO 3.6.1