Espritmodel.com Telemetry Radio
Reply
Thread Tools
Old May 09, 2013, 06:19 AM
Registered User
kodak_jack's Avatar
Hilton (Rochester), NY
Joined Mar 2008
9,675 Posts
You usually have to wade through a ton of 3 channel heli stuff to get here.
kodak_jack is offline Find More Posts by kodak_jack
Reply With Quote
Sign up now
to remove ads between posts
Old May 09, 2013, 06:30 AM
Rockin' & Flyin'
Saxguy1000's Avatar
Virginia Beach
Joined Dec 2009
2,794 Posts
Sorry if this is answered somewhere here. I searched and couldn't find it...

Do the mCX2 lights work in the gear or x-port channel of the AR6400? Thanks in advance.
Saxguy1000 is offline Find More Posts by Saxguy1000
Reply With Quote
Old May 21, 2013, 12:51 PM
Master of Micro Modding
valiantGLX's Avatar
Australia, SA, Burra
Joined Sep 2011
2,480 Posts
Quote:
Originally Posted by Saxguy1000 View Post
Sorry if this is answered somewhere here. I searched and couldn't find it...

Do the mCX2 lights work in the gear or x-port channel of the AR6400? Thanks in advance.
No unfortunately, same connecter but they dont work properly (you can get 1 or two of the lights to stay solidly lit though)
valiantGLX is online now Find More Posts by valiantGLX
Reply With Quote
Old Aug 14, 2013, 08:08 PM
Registered User
Joined Feb 2013
59 Posts
After having to replace the upper main blades my mcx2 gets tbe, but only when flying forward/backward with left rudder input. Flies right just fine. I am boggled.
Dohman is offline Find More Posts by Dohman
Reply With Quote
Old Aug 15, 2013, 01:55 AM
Master of Micro Modding
valiantGLX's Avatar
Australia, SA, Burra
Joined Sep 2011
2,480 Posts
Quote:
Originally Posted by Dohman View Post
After having to replace the upper main blades my mcx2 gets tbe, but only when flying forward/backward with left rudder input. Flies right just fine. I am boggled.
Flip the flybar around, that should help a bit
valiantGLX is online now Find More Posts by valiantGLX
Reply With Quote
Old Aug 16, 2013, 12:51 PM
Scout CX | mCX2 | mSR | 120SR
North_of_49's Avatar
Canada, AB, Edmonton
Joined Dec 2011
6,436 Posts
Quote:
Originally Posted by Dohman View Post
After having to replace the upper main blades my mcx2 gets tbe, but only when flying forward/backward with left rudder input. Flies right just fine. I am boggled.
describe what you're observing that you think is TBE.
North_of_49 is online now Find More Posts by North_of_49
RCG Plus Member
Old Aug 19, 2013, 06:29 PM
Registered User
Joined Feb 2013
59 Posts
Wobbles in more or less a flushing water looking pattern. Only on left input. The motion is back and forth. It doesnt wonder anywhere or anything. It just does not maneuver left well at all. Circular wobbling motion, would be the best description i guess.
Dohman is offline Find More Posts by Dohman
Reply With Quote
Old Aug 19, 2013, 10:53 PM
Scout CX | mCX2 | mSR | 120SR
North_of_49's Avatar
Canada, AB, Edmonton
Joined Dec 2011
6,436 Posts
Quote:
Originally Posted by Dohman View Post
Wobbles in more or less a flushing water looking pattern. Only on left input. The motion is back and forth. It doesnt wonder anywhere or anything. It just does not maneuver left well at all. Circular wobbling motion, would be the best description i guess.
That's not TBE, that's the death wobble. Search this or any other mcx2 thread for that term and you'll find alot of talk on it. If you use the advanced search so you can narrow results to my posts only and using that term you'll find an explanation why it happens. If you can't find it pm me.

By the way, there's nothing you can do about it (because of why it happens). I'll try to find links to my explanation of it when I have some time but it won't be tonight... need to catch up quickly on my forum subs then crash.
North_of_49 is online now Find More Posts by North_of_49
RCG Plus Member
Old Aug 20, 2013, 03:58 AM
Master of Micro Modding
valiantGLX's Avatar
Australia, SA, Burra
Joined Sep 2011
2,480 Posts
Quote:
Originally Posted by Dohman View Post
Wobbles in more or less a flushing water looking pattern. Only on left input. The motion is back and forth. It doesnt wonder anywhere or anything. It just does not maneuver left well at all. Circular wobbling motion, would be the best description i guess.
As north said it is normal for a bit of death wobble, but you can minimize it. Oil the bearings with some tri-flow lube, reverse the battery orientation and mechanically trim it, a 160mah battery may help too (extra weight), swap out the innershaft and sometimes removing the flybar and flipping it around then reinstalling it helps too.
valiantGLX is online now Find More Posts by valiantGLX
Last edited by valiantGLX; Aug 24, 2013 at 05:09 AM.
Reply With Quote
Old Aug 20, 2013, 06:38 AM
Scout CX | mCX2 | mSR | 120SR
North_of_49's Avatar
Canada, AB, Edmonton
Joined Dec 2011
6,436 Posts
Gotta head to work, but the short answer is... death wobble is because the rotor that drives the flybar (the thing that stabilizes the heli) slows down or even stops spinning altogether in left turns (because of the way a coax works in the first place). You can test this yourself on the bench

... no stabilzing spinning flybar... death wobble.
North_of_49 is online now Find More Posts by North_of_49
RCG Plus Member
Old Aug 25, 2013, 04:18 PM
Registered User
Joined Feb 2013
59 Posts
Hrmmm. Whats killing me is it did not fly this poorly prior to replacing the upper main blades, so in my mind there must be some issue. Balance or a motor wearing out or something.

Tried flipping the flybar, no difference. And I mean drastic death wobble. Before it would do it some on left turns when flying aggressively. Now it is literally not possible to maneuver forward and left simultaneously. Very frustrating. Sorry for the slow responses, been working far too much recently.

I think my next move is to try a new upper blade hub. Have tried different blades, top and bottom. Flipping the flybar. There does not seem to be any abnormal vibration issues, nothing had changed but the upper blades. Reading other posts there does not really seem to be a universal cause or solution. Most just seem to accept it as part of coax. I cant because it only recently got bad like it is now.
Dohman is offline Find More Posts by Dohman
Reply With Quote
Old Aug 25, 2013, 09:37 PM
Scout CX | mCX2 | mSR | 120SR
North_of_49's Avatar
Canada, AB, Edmonton
Joined Dec 2011
6,436 Posts
If it actually is the death wobble, then, yes, it's inherent to the design of this coax which uses the top rotor to drive the stabilizing flybar...

When you have no rudder input (I should have mentioned it's left rudder command that we're talking about, not aileron) then both top and bottom rotor rotate at equal rpm's but in opposite directions... they counter each other (torque) therefore the tail stays pointed in one direction. When you give a rudder command, you are slowing down one of the two rotors breaking the rpm equilibrium so the heli will now yaw in one direction or the other depending whether you gave it left or right rudder which determines which rotor, top or bottom, will slow its rotation.

When you give a left rudder command on the mcx2 it's the top rotor that slows in rpm... give full left rudder and that top rotor will actually completely power down which, again, you can test on the bench holding the heli down by the skids (obviously, you need to give it some throttle first). So now your flybar as well is spinning either slow or not at all and you lose its stabilizing effect.

I'll have to fire mine up sometime and try a left rudder pirouette... it should go into death wobble... but I don't remember having (left) pirouette problems when I used to fly it... hmmm. Then again, it's not a maneuver that interested me much so I probably only did them a few times... maybe it was always with right rudder? I'd have to think about it, but, during a left pirouette I guess you could say the flybar is still spinning if you think in relative terms... to what the heli's body is doing. I'll have to fire it up sometime like I said and watch what's going on there... haven't flown it in a year.


I have a vid on youtube flying outdoors a couple of winters ago... I go into death wobble a couple of times just from trying to descend too fast by chopping the throttle which drops rpm on both rotors simultaneously so, again, the flybar has spun down as well.


Maybe your problem isn't the death wobble... a vid posted to youtube and linked to here would help.
North_of_49 is online now Find More Posts by North_of_49
RCG Plus Member
Old Sep 03, 2013, 11:49 PM
Certifiable
stringrazor's Avatar
United States, CA, Burbank
Joined Dec 2012
2,134 Posts
A friend found an MCX2 frame (no canopy or boom) at a garage sale (seller gave it to him included with other purchases). Since I'm pretty good at heli repairs, he brought it to me, just to see if I can get it in the air. It powers up and binds to the Tx. The servos respond correctly but when I try to spool up, the motors start but then the board seems to no longer respond to input, throttle or cyclic. I'm fairly sure the lipos are good ( think he flies his MSR with them). the power wire connections to the board look OK but I suppose I should reflow the solder anyway. Any other correctable issue I should look for before I write off the Rx board as failed?
stringrazor is online now Find More Posts by stringrazor
Reply With Quote
Old Sep 04, 2013, 03:45 AM
Master of Micro Modding
valiantGLX's Avatar
Australia, SA, Burra
Joined Sep 2011
2,480 Posts
Quote:
Originally Posted by stringrazor View Post
A friend found an MCX2 frame (no canopy or boom) at a garage sale (seller gave it to him included with other purchases). Since I'm pretty good at heli repairs, he brought it to me, just to see if I can get it in the air. It powers up and binds to the Tx. The servos respond correctly but when I try to spool up, the motors start but then the board seems to no longer respond to input, throttle or cyclic. I'm fairly sure the lipos are good ( think he flies his MSR with them). the power wire connections to the board look OK but I suppose I should reflow the solder anyway. Any other correctable issue I should look for before I write off the Rx board as failed?
The brushes in the motors may be broken, I had a similar experience once because of that very reason
valiantGLX is online now Find More Posts by valiantGLX
Reply With Quote
Old Sep 05, 2013, 11:54 AM
Certifiable
stringrazor's Avatar
United States, CA, Burbank
Joined Dec 2012
2,134 Posts
Quote:
Originally Posted by valiantGLX View Post
The brushes in the motors may be broken, I had a similar experience once because of that very reason

Thanks. I'll try alternately unplugging a motor. It's pretty unlikely, tho' possible, that both motors have broken brushes.
stringrazor is online now Find More Posts by stringrazor
Reply With Quote
Reply


Thread Tools

Similar Threads
Category Thread Thread Starter Forum Replies Last Post
Question BLADE MCX 2 Vibration issues valiantGLX Coaxial Helicopters 8 Mar 26, 2012 12:48 PM
Sold Spektrum DX6i w/Blade 400 3D, RTF HeliMax AXE CPV3...LOWERED PRICES!! ABADGTP Non R/C Items (FS/W) 7 Sep 22, 2011 09:58 PM
Data Dx6i mcx settings Stugoose Coaxial Helicopters 6 Sep 20, 2011 05:01 PM
Discussion BLADE MCX 2 Vibration issues valiantGLX Electric Heli Talk 0 Sep 11, 2011 03:33 PM
Discussion DX6I and Blade CX2, MCX Problems streek Multirotor Talk 2 Sep 11, 2011 03:17 PM