[How to] fix vibration on mCX 2 with Carbon fiber Tail Boom

[Pfloyd]

Change out tje blades...see it they are tracking right.

[Marine6680]

Watch the video I posted in the OP.

I am not a heli noob... I have checked blades and tracking and all the normal areas. This mCX is my fiance's, she is new to helis.

Like I said... I am not complaining nor asking for help. I am trying to help others fix the issue. I have already found and fixed the problem on mine. I think this may help others.

[Pfloyd]

Is the 5n1 on snug?

[Marine6680]

Yup checked that first I believe.

[Marine6680]

Update:

Got a new canopy.

Final Evolution Carbon Fiber Canopy

Tried it out and got the vibration just like before.

So I drilled out the back mounting holes to about 1/8 inch diameter. That allowed it to not be tight on the rear canopy mounting posts.

That fixed the vibration just like I show in my video in the OP. I would think this would work on the stock canopy as well

Also, the silver CF canopy is pretty nice looking.

[GG07]

I think I mentioned this earlier or in another thread but it bears repeating.

One often overlooked cause of tail shake/wobble is improperly seated rotor main gears. Just a little tilt in how they are attached to shaft can transmit a significant amount of shimmy to the tail boom.

Both my MCXs had wobbly main gears out of the box, as did my first MCX2. Just pop then off and carefully reseat them making sure that they are perfectly level on the shaft with no wobble.

After doing this, both of my MCXs were perfectly still with any level of RPM. Prior to doing this, they both had a lot of tail shimmy, especially at lower RPMs.

Just a thought, in case you haven't checked those gears.

Cheers.

[RoboHeli]

That's good advice and is certainly easy to do. I'd also recommend adding a bit of triflow or dry teflon lube (for bike chains) to the main gears as well to help reduce any friction.

[GG07]

Originally Posted by MrRoboHeli

That's good advice and is certainly easy to do. I'd also recommend adding a bit of triflow or dry teflon lube (for bike chains) to the main gears as well to help reduce any friction.

Good tip! I will have to pick some of that up! Have been wondering about a good dry lube for the moving parts like the gears and pinions

All I have on hand that would work with such tiny components is White Lithium grease which works well on the inner shaft and the linkages from the swashplate to the lower rotor. I also dabbed some on the servo rails using a darning needle. Makes a huge difference in the sound of the servos. They get "really" quiet after greasing those rails inside the servo box itself. Wouldn't work so hot on the gears since it will likely fly off and collect on the inner side of the body next to the gears on the MCX2.

[RoboHeli]

I've heard good things about "Finish Line" dry teflonlLube

http://www.amazon.com/Finish-Line-Bi.../dp/B002IDZXRM

[Pfloyd]

I use this stuff.




Everyone want to know what to lube the links and balls, so simple it is funny. Use a pencil. Rub the pencil lead on the balls...instant graphite dry lube, works great!

[Marine6680]

Never thought of that... I use Boelube it works well.

[GG07]

Originally Posted by Pfloyd

I use this stuff.




Everyone want to know what to lube the links and balls, so simple it is funny. Use a pencil. Rub the pencil lead on the balls...instant graphite dry lube, works great!

Thats the stuff I ordered from Amazon earlier. Was hoping it was comparable to what was suggested. Glad to hear that it is!

[Pfloyd]

Tht is it...got mine at my local bike shop.

[f357]

I had a vibration on my mcx with the carbon tail boom. Tried flying it today with the rear canopy mounts not pushed onto the frame. No more vibration. So my fix was to remove the gromets from the canopy. Now it flys wiyh no vibrations.

[Marine6680]

Originally Posted by f357

I had a vibration on my mcx with the carbon tail boom. Tried flying it today with the rear canopy mounts not pushed onto the frame. No more vibration. So my fix was to remove the gromets from the canopy. Now it flys wiyh no vibrations.

Cool... I thought of that after I got the new canopy but I can't edit the OP

I just enlarged the top holes in the new canopy.


Basically I think it is wave resonance causing the issue... just like feedback in a speaker.

The small vibrations in the frame enter the canopy which is light weight so it vibrates more than the frame will. Then the vibrations transfer back into the frame through the mounting posts. Now you have vibrations entering the frame from the upper and lower posts. The two waves of vibration meet each other and amplify. It is probably a freak result of component placement. The board and its gyros are in just the right spot to pick up the amplified vibrations which makes it even worse.

Isolating the board from the frame vibration somehow might help as well, but just using larger holes for the upper mounts is easier.

[daveotlinux]

Just added the CF boom to my mCX2. It of course had the vibration problem. Found this thread when I started searching for a reason.

I tried the canopy adjustment first, but it only helped a little. I then added the grommets to the landing skids, and noticed the following:

The upper blade shaft and gear had a lot of play. I did not notice this when I put the helicopter away yesterday.

The other change was to push the boom into the holder until it touched the vertical shaft holding the bearings.

I am including 2 pictures showing how I have the canopy placed.

http://db.tt/FbiTtnYl
http://db.tt/N5Pcd8no


Here is the link to youtube.

[ame]http://youtu.be/TPX6VFIOwJs[/ame]

[Marine6680]

I used a hole punch to open up the upper mounting holes, then installed the canopy like normal and that fixed the vibration... Not allowing the canopy to touch the frame at the upper mounting holes stops the vibration.

[blade64]

Awesome worked for me thanks so much. I have tried everything to rid my mcx2 of that horrible tail vibration including everything mentioned previously in this post.

Great work man, greatly appreciated

[Marine6680]

Glad it helped.

[Pfloyd]

If you want to fix the tail vibrations with out muxxing up the canopy..do what I did..stopped my vibrations...take the weight off of the tail boom...take the two rubber o-rings and through them away....use two canopy grommets from a regular mcx and use them to hold the weight tight......seems on mine the weight was flopping around and causing the vibes.