New Products Flash Sale
Thread Tools
Old Jun 12, 2015, 11:36 AM
Chap1012 is online now
Find More Posts by Chap1012
Epilepsy Awareness
Chap1012's Avatar
United States, MA, Malden
Joined Mar 2008
13,240 Posts
Quote:
Originally Posted by Capt. Thomas View Post
Ok thanks Chap. Now the next thing that has popped up. In several posts and as North has explained, when you spin up the rotors and give full left or right rudder one blade is supposed to stop spinning (well almost since air movement may "push" it a little) right? Like as in no power? My MCX2 "pulses" the reduced power rotor set but does not shut completely down. Is this normal?

Capt. Thomas
Yup, that's normal. This is how the rudder works on a coax. Either rotor won't completely shut down. I don't know about doing "pirouettes". Hold her down on the table and give about 75% throttle. Move the rudder stick hard right and left. This will simulate a pirouette. See what happens.

The only way I can see your rotor pulsing is maybe the stick is not fully at 90. If I could see a vid, I could tell you more. If you have to apply a lot of trim on the rudder that could be a sign one of the motors are going bad (tip: always replace both motors and not just one).

Mike.
Chap1012 is online now Find More Posts by Chap1012
Last edited by Chap1012; Jun 12, 2015 at 11:55 AM.
Reply With Quote
Sign up now
to remove ads between posts
Old Jun 12, 2015, 12:43 PM
North_of_49 is offline
Find More Posts by North_of_49
Scout CX | mCX2 | mSR | 120SR
North_of_49's Avatar
Canada, AB, Edmonton
Joined Dec 2011
9,152 Posts
Quote:
Originally Posted by Capt. Thomas View Post
Ok thanks Chap. Now the next thing that has popped up. In several posts and as North has explained, when you spin up the rotors and give full left or right rudder one blade is supposed to stop spinning (well almost since air movement may "push" it a little) right? Like as in no power? My MCX2 "pulses" the reduced power rotor set but does not shut completely down. Is this normal?

Capt. Thomas
Actually, my post says one will shut completely down IF you only run up the throttle enough to just get them going. That's for demonstration to make it easy and totally obvious to see what's going on...

... and that at actual flying rotor speeds, one will only slow down (not shut completely off).

I'll post a video later.
North_of_49 is offline Find More Posts by North_of_49
RCG Plus Member
Old Jun 12, 2015, 01:56 PM
North_of_49 is offline
Find More Posts by North_of_49
Scout CX | mCX2 | mSR | 120SR
North_of_49's Avatar
Canada, AB, Edmonton
Joined Dec 2011
9,152 Posts
Quote:
Originally Posted by North_of_49 View Post
Actually, my post says one will shut completely down IF you only run up the throttle enough to just get them going. That's for demonstration to make it easy and totally obvious to see what's going on...

... and that at actual flying rotor speeds, one will only slow down (not shut completely off).

I'll post a video later.
Here you go

(yes, there is a pulsing at minimum throttle with full rudder, don't know why but it doesn't matter, you'd never be flying in that stick configuration, it only happens in this demo situation)...


Balde mCX2 rudder demo for RCGroups (0 min 33 sec)
North_of_49 is offline Find More Posts by North_of_49
RCG Plus Member
Last edited by North_of_49; Jun 12, 2015 at 02:11 PM.
Reply With Quote
Old Jun 14, 2015, 10:23 AM
Capt. Thomas is offline
Find More Posts by Capt. Thomas
Wing Driver - You buy, we fly
Guam
Joined Nov 2012
205 Posts
Ok North thanks! Yours pulses like mine. Funny though, even at full throttle it does it? You would think that it would make the flight super "jerky" like that?

Capt. Thomas
Capt. Thomas is offline Find More Posts by Capt. Thomas
Reply With Quote
Old Jun 14, 2015, 10:27 AM
Capt. Thomas is offline
Find More Posts by Capt. Thomas
Wing Driver - You buy, we fly
Guam
Joined Nov 2012
205 Posts
I have a nice one for sale in the classifieds if anyone is interested? I had two for junior and I and this was mine so it's like new. I'm going to keep the one junior was flying just because I like it and it has a few scrapes so I can start mods on it!

Capt. Thomas
Capt. Thomas is offline Find More Posts by Capt. Thomas
Reply With Quote
Old Jun 14, 2015, 10:33 AM
Chap1012 is online now
Find More Posts by Chap1012
Epilepsy Awareness
Chap1012's Avatar
United States, MA, Malden
Joined Mar 2008
13,240 Posts
Quote:
Originally Posted by Capt. Thomas View Post
I have a nice one for sale in the classifieds if anyone is interested? I had two for junior and I and this was mine so it's like new. I'm going to keep the one junior was flying just because I like it and it has a few scrapes so I can start mods on it!

Capt. Thomas
Capt, you'd be better off keeping it for spare parts OR teach someone else to fly Trust me, she'll come in handy one day

Mike.
Chap1012 is online now Find More Posts by Chap1012
Reply With Quote
Old Jun 14, 2015, 12:20 PM
North_of_49 is offline
Find More Posts by North_of_49
Scout CX | mCX2 | mSR | 120SR
North_of_49's Avatar
Canada, AB, Edmonton
Joined Dec 2011
9,152 Posts
Quote:
Originally Posted by Capt. Thomas View Post
Ok North thanks! Yours pulses like mine. Funny though, even at full throttle it does it? You would think that it would make the flight super "jerky" like that?

Capt. Thomas
Yeah, I noticed during testing for my video that it did seem to do it a bit at full throttle too and even at mid throttle but only on the left (and the video seems to show that). I don't think it's affecting flight (unless it's contributing to left turn death wobble. I'll test full throttle full right rudder later today to see if that's pulsing too... it's the one thing I didn't do in the video).

That aside, the video is just to demonstrate how one rotor or the other slows down depending which rudder direction you command, and how that causes the stabilizing flybar to slow down in hard left rudder turns which makes sense to me that that's why you get the death wobble. Especially since you get the same wobble when the flybar slows down just from lowering the throttle too much to descend quickly when at altitude like seen in my outdoor video I posted.
North_of_49 is offline Find More Posts by North_of_49
RCG Plus Member
Old Jun 14, 2015, 11:07 PM
Chap1012 is online now
Find More Posts by Chap1012
Epilepsy Awareness
Chap1012's Avatar
United States, MA, Malden
Joined Mar 2008
13,240 Posts
I don't see the blades pulsating but, I do hear the gears pulsing. I would think that that would be normal. Just my 2

Mike.
Chap1012 is online now Find More Posts by Chap1012
Reply With Quote
Old Jun 14, 2015, 11:17 PM
North_of_49 is offline
Find More Posts by North_of_49
Scout CX | mCX2 | mSR | 120SR
North_of_49's Avatar
Canada, AB, Edmonton
Joined Dec 2011
9,152 Posts
Quote:
Originally Posted by Chap1012 View Post
I don't see the blades pulsating but, I do hear the gears pulsing. I would think that that would be normal. Just my 2

Mike.
It's the throttle/motors (ESC) you hear pulsing
North_of_49 is offline Find More Posts by North_of_49
RCG Plus Member
Old Jun 15, 2015, 01:42 AM
Capt. Thomas is offline
Find More Posts by Capt. Thomas
Wing Driver - You buy, we fly
Guam
Joined Nov 2012
205 Posts
Yes I think the ESC is working PWM of the power signal. Not sure how that works into the wobble but it has to be a factor, to what extent I would need to investigate but it is there. Common engineering principle dictates that a pulse in power requires torque offset (in this case a fly bar) to prevent over run. All things in the A/E world are a trade off .

Capt. Thomas
Capt. Thomas is offline Find More Posts by Capt. Thomas
Reply With Quote
Old Jun 15, 2015, 01:53 AM
North_of_49 is offline
Find More Posts by North_of_49
Scout CX | mCX2 | mSR | 120SR
North_of_49's Avatar
Canada, AB, Edmonton
Joined Dec 2011
9,152 Posts
That's not the PWM you're hearing, PWM in most ESC's happens at about 12000Hz... it's the high pitch squeal you hear coming from some of them like an old CRT television... drives me nuts on some of my planes and I don't know why they can't up the PWM frequency to something beyond human hearing. The PWM LED dimmers I was using for video production run at 30, 000Hz for just that reason, so they are silent to microphones.

The pulsing in my video is more like 4Hz.
North_of_49 is offline Find More Posts by North_of_49
RCG Plus Member
Last edited by North_of_49; Jun 15, 2015 at 11:43 PM.
Reply With Quote
Old Jul 03, 2015, 11:32 AM
Jake8131 is offline
Find More Posts by Jake8131
Jake From Planet Mascoutah, IL
Jake8131's Avatar
United States, IL, Mascoutah
Joined Dec 2010
3,684 Posts
Fooling around very early this morning.


TRANSFORMATION A (2 min 18 sec)
Jake8131 is offline Find More Posts by Jake8131
Reply With Quote


Thread Tools

Similar Threads
Category Thread Thread Starter Forum Replies Last Post
Sold Eflite Blade MSR Plus 2.4ghz Eflite Transmitter soaringcam Aircraft - Electric - Helis (FS/W) 4 Apr 07, 2010 10:27 AM
Sold EFLITE BLADE MSR+BLADE 400+DX6i dhmojo Aircraft - Electric - Helis (FS/W) 7 Mar 29, 2010 10:38 PM
Sold Blade MCX2 LNIB mgroves Aircraft - Electric - Helis (FS/W) 1 Mar 23, 2010 11:17 AM
For Sale Trade, eflite blades for eflite blades....Sell Blade CP Pro NIB with extras. kdill2160 Aircraft - Electric - Helis (FS/W) 1 Sep 02, 2006 09:28 AM
Alert Eflite Blade CX - 2nd Eflite heli jschenck Coaxial Helicopters 26 Oct 24, 2005 01:48 AM