Extreme Yaw Rate CX2

[addicted]

`Yes' I am a newbie! Have flown the CX2 about 10 times and was doing pretty well with it until I flew out of the range of the supplied TX. Used my DX7 previously but it was elsewhere. The heli just turned itself off and fell to the ground from about 20'. As I walked closer I could hear one of the motors running, dropped the throttle which I had bumped to the 'on' position as I walked to the heli after the crash, and noticed one of the gears must have chewed some of the body apart. Testing revealed the right motor suffered some damage. Plugged it into the other motor port on the receiver and it acted the same.
I sent for parts. Had to replace the right motor. Replaced some shafts and installed a tail boom as the rear fuselage was toast. Re-assembled, I had done it before because of a mutltiple blade strike as I was stick banging outside in the wind, and when I spooled up and as the thing got light on the skids it spun counter clockwise about 360 degrees in 2 seconds. Of course I shut it down and played with the proportional and it didn't touch the problem even if I turned it to one extreme or the other. Looked down on the rotors and they are turning the correct direction according to the manual.
WIthout some help from you 'experienced' pilots, I am SOL.:(

[jrohland]

The motors on the CX2 are plugged in in opposite directions. Since you replaced the right motor, I would try flipping it's plug. See page 20 of the manual: CX2 manual (http://www.horizonhobby.com/ProdInfo/Files/Blade_CX2_Manual.pdf).

jrohland

[addicted]

Double checked the instructions on the product supply update sheet for the 3&1 and motors are connected as instructed. Just tried it again. For awhile it seemed be normal except the yaw rate was extrememly fast on just slight input but it wasn't spinning like a kids top. Tried to adjust proportional and after a major change in Proportional adj. it went back to the yaw rate like I was holding on to one rotor and then powering up. Still stumped what to try

[addicted]

Took the battery tray and shafts out of the CX2 frame and unplugged both motors from the 3/1. Keeping the polarity as shown on the plastic 3/1 case, I plugged the right side motor, just replaced it today, into M1 and then into M2. The motor went to what sounded like full speed and was the same in both slots. I then took the left side motor and did the same thing. When it was plugged into M1 the speed of the motor sounded like what the speed was with the other motor in both the slots but when I plugged the motor into the M2 slot the motor spun noticeably faster. The one motor running faster would certainly create the spinning top yaw.
Anyone know what is going on? I repeated this routine several times with the same results. I hadn't been drinking either. Any thoughts about what is happening would be appreciated.

[Blue Thunder]

Just a thought,
I would change out both motors so both are new.

[addicted]

I also came to the conclusion that it would be a good idea to change both motors. However, I did attempt to check the voltage coming out of the 3/1. If the voltage read the same then it would be a motor problem. If the voltages were different it would be a 3/1 problem. I'll never know! I was in a hurry and when I tried to take the voltage reading with the leads on the probe, I shorted one post to the other. Fried the 3/1. Strangely, the port where I shorted the terminals still worked. However the other port is totally dead. So...I tried 3 different places before I could find a new 3/1. It'll be here Saturday and then I'll start over. For what I have spent on parts, I could've gotten a new heli.

[Kindling Maker]

I know the feeling, I spent so much on a CPPro that I could have bought a Trex

[BigAl07]

I'm having the exact same problem except I've not replaced a MOTOR!! Maybe I need to order a "Motor Kit" or something.

Allen

Took the battery tray and shafts out of the CX2 frame and unplugged both motors from the 3/1. Keeping the polarity as shown on the plastic 3/1 case, I plugged the right side motor, just replaced it today, into M1 and then into M2. The motor went to what sounded like full speed and was the same in both slots. I then took the left side motor and did the same thing. When it was plugged into M1 the speed of the motor sounded like what the speed was with the other motor in both the slots but when I plugged the motor into the M2 slot the motor spun noticeably faster. The one motor running faster would certainly create the spinning top yaw.
Anyone know what is going on? I repeated this routine several times with the same results. I hadn't been drinking either. Any thoughts about what is happening would be appreciated.

[addicted]

Please don't repeat the mistakes I made. I would have liked to have known if the voltages coming out of the 3/1 were identical. I have a good Fluke meter, and it has nice insulated tips for grabbing small things but I didn't use them, and if I had been careful and not shorted it out I might have known. From this forum and people I have talked with at the LHS and some of the online suppliers I think it's logical to say the extreme yaw has to come from one rotor moving much faster than the other. WHY that is happening could come from a variety of things. Basically it's either mechanical or electrical. One motor might be more/less effecient/worn than the other and the proportional electrical mix can't match the differences. The 3/1 may be defective. On the mechanical side, anything from bent shafts, tired bearings, to gears slipping on the drive motors could be the mechanical reasons. Probably some more that others could explain. I guess you just start out and eliminate them one at a time. Then you're still not sure exactly what it was because it may be two things you fixed that made it right, not just the last thing you did. I'll let you know what happens to mine. Hope to hear from you too.

[Hawk18052]

If ya pay shipping I'll send it to you for free, burnt one and 1 still lives. Actually I let my friend fly it and he got it stuck in a tree, tryed to free it by giving it power which burnt the chip. Still have one that flys though.

That is all,
Hawk

[addicted]

I'm up for that. Very kind of you to offer. PM sent.

[addicted]

Maybe this is the end of the story. Got the new 3/1 late today. Installed it and all is well. I think maybe the one motor I replaced is really good. I'll save it until I might want to exchange it with another one to see. Wonder if the resistance through the motor windings would tell me anything?
Like someone suggested the gyro went and their really wasn't anything wrong with the motors.

[Bradnplanes]

I have found many of the Extreme motors with loose brush holders , you can veryify this by running the motor at full speed from the controler and just touching the brush holder so it gets a bit tighter on the armture wile its running , you will have a big increase in speed if the problem is in the brush holder ...

[Bradnplanes]

Its a simple fix ,, dont overlook it..... I found 2 motors right out of the box this way , and I even found new brushes that have the contactor block turned 45 degrees... I really like the extreme motors when you get them working right you will love them...

[skunkworx]

I've had almost the exact opposite problem. I just installed 2 brand new Extreme 180 motors and my heli seems way less responsive now. I still get the sligt nose drift to the right, but when I give it some left nose, it either keeps drifting to the right, or snaps to the left without any rhyme or reason. I'll try playing with the brushes, but if that doesn't work, then I'm totally going full brushless and just forgetting about the brushed stuff altogether!

[singingperry]

Very common complaint, many times myself, usually I did not make sure the set screws in the large bottom gear did not go all the way ithrough the stem in the gear to contact with the rotor shaft which causes slippping. When replacing the motors make sure and replace both, xtreme 180s are well worth the investment. There is a set screw on the upper rotor head that clamps onto the shaft, make sure thats tight though i haven't had that problem yet. Reply if your problems not solved. The old 4-n-1's were usually the culprit but they're much better now

[skunkworx]

I have a 3n1 with the 2.4Ghz TX/RX. One thing I noticed yesterday while flying(probably because it was dark outside). There's a little green LED on the left side, and it shines when it's locked in or at low motor RPM, but once you get it in the air within a few seconds the light goes red and the tail doesn't hold for anything. I don't really think this is a 3n1 problem,but if it is I happen to have one in my garage that I can swap it out with, but if you say it might be a motor problem, I'll try that first.
When I try to adjust anyting, neither the gyro or the mix potentiometers do anything to the controls. I have to hold the stick full left just to keep it straight and even then it still drifts to the right. When I let go of the stick and give it a little jab, it will bump the nose left a little bit, but it starts to drift again. It never did this with the stock motors.

I just thought of something.....are both of the motor exactly the same? I bought 2 of the same motors not realizing there was an A and a B. Could this be causing the problem? I on't really see how it would, but in case it is, would I need to order a new one, or can I fix this one?

[waspo]

Do you mean you bought 2 motors of 'A' or 'B'? That would be a big problem as you won't be getting any contact on the specific cog and even if you did, it will be very limited. You need to get a 'A' or 'B' depending what you have at the moment and make sure they're in the right position. From memory 'A' motor for top blades/cog nearest the battery and 'B' for the bottom blades/cog nearest the frame base.

[skunkworx]

Yes, I belive they were 2 B's as I had to push the pinion down on the shaft to make contact with the upper gear. I complained to HD and they said that they need a few break-in flights in order to work best. I have a Duratraxx ICE charger with a motor break-in function on it. I set it to 10 minute cycles @ 7.0V. Current readings at first were up around .52A, but after 2-3 cycles it started to drop down to around .42 and leveled off leaving me to believe this is as close to norml as I can get it without burning more sensible life out of the brushes. Just as a reference, the stock motor only ran at .38-.42A, so it seemed like a good stopping point.

Another thing I think I had screwed up was the motor order (complete bone-head move here). In the manual, it says that motor A is supposed to power the top blades, and B the lowers. Seeing they both speed up or slow down to control yaw, I figured it didn't matter which order I had them plugged in, but I'm guessing that's not so. Once I switched the motor leads around and re-did the gyro/mixer/radio potentiometer, it seemed to fly great! The heat sink really helps keep the motors on ice and I'm installing the last piece of aluminum upgrade on it when my parts order shows up (hopefully tomorrow!!!). I'll see how it flys once I can get my blade tracking back to normal with the new blades (been flying around with a chipped up/repaired blade on bottom) and let you know how it goes from there.

[goldslinger]

I've had almost the exact opposite problem. I just installed 2 brand new Extreme 180 motors and my heli seems way less responsive now. I still get the sligt nose drift to the right, but when I give it some left nose, it either keeps drifting to the right, or snaps to the left without any rhyme or reason. I'll try playing with the brushes, but if that doesn't work, then I'm totally going full brushless and just forgetting about the brushed stuff altogether!


The brushes are fine! They look like they are turned wrong, but that is purposeful for wearing in; they will make full contact after several flights.

It WILL take several flights to fully enjoy full power from these, but until the brushes are fully seated, they will seem sluggish. Break them in gently; don't let them get too hot.

Gary

[Tiger]

same here for me the cp was time and money wasted that i could have use on a texx 600

[Kindling Maker]

So what are you flying now? Did you ever get the 400 or are you still flying the CX2 that hit the Antenea on H-4?

[skunkworx]

I got my motors broken in. Heli flys perfect! I still get some drift, but that's largely due to the crappy gyro. They don't really feel as smoothe as the stock motors. Maybe they need a little more break-in, but I think that these motors are just a little under powered or too low "Kv" rating. Beats me.....at least they run cooler

[Kindling Maker]

Get them broken in and they will be better. Some people throw the 11.1 under it, I dont see how you gain much considering the weight difference and the fact that I really believe that it is hard in the 4 in 1. Just get the motors broken in and get the boom tail from Boomtownhobbies.com. They also have the extension mod for the rotors and that helps alot. Stay away from the CNC head. They are fun little birds.

[skunkworx]

They might need a few more flights to feel 100%, but they still feel a little on the weak side and I cant imagine them getting a drastic enough of an improvement to convince me otherwise. I'll just have to live with it I suppose.

I have the 3n1 on both of my helis (they're the newest type out with the 2.4Ghz radios). It's the same one as in my CP Pro, so 11.1V won't hurt it at all. I already have the CNC stuff. I know they don't add much to performance, but I like the durability. Blades are cheap and easy to get to, so I'd much rather change them out over a hub replacement!