I'm giving up the brushless mod!

[andrej2k]

I've been tweaking and tuning my dear mcpx the last couple of months, but the more money I put into it, the more problems occure.

The story of my mCPX:
At first I bought the "CO5 Brushless Main Motor, StevePCB, XP-7A" from wowhobbies to get some more power (http://www.wowhobbies.com/mcpxbrushl...rsionkitp.aspx). This is the light BL version. The heli started to do the 90 degree clockwise spin now and then. I read a lot about this problem on helifreak. The first thing I did was to extend the tail boom. Didn't help. Then I changed the tail to the 120 sr. No difference. Then I installed the wowhobbies 120 sr tail mod for mCPX with no luck.

Meanwhile I also changed main shaft (this was a common suggestion from helifreakers), links, bearings, main frame, blades (tried a lot different ones), CNC aluminium metal head combo upgrade (something cheap, http://www.ebay.com/itm/CNC-Aluminiu...item3a7ee1ff29. Nothing has made any difference. Have yet to try a microheli swashplate, but I don't see how that will change anything.

Yesterday, received a hp06v2 motor in the mail. I know my xp-7a is a bit weak, but astroid-designs says this work just fine, only with lower gov. Link to that statement: http://astroid-designs.myshopify.com...rushless-motor

After installing the little bastard I was eager to try it. I got in the air, but the 90 deg clockwise turns got much worse (probably should have expected that). I lost control due to too much involuntary spins, hit TH and got a little harder landing than planned.. That resulted in main rotors not spinning. The tail blades spins perfectly and all the servos are working correctly. Is it possible that I burned the xp-7a? I think throttle curve was 100%, 90%, 80%, 90%, 100% in idle up (dx8). Maybe a bit too much?

Now, the mcpx is back in its suitcase, and it will probably not see the sunlight again unless someone can tell me where to begin to fix my problems once for all.

1. What more can be done to fix the 90 degree clockwise spin?
2. What do you think is the problem with the main rotors not spinning?

Link to full resolution picture of my heli: www.trellaern.com/bildeheli.jpg

[NCcraig]

That upgrade kit is a cheap knock CNC kit and isn't worth the money you spent on it. If you have one of Dylan's ESC's that is flashed, you need to be running flat throttle curves if it is set to the default TX GOV settings. The spin you have is due to a vibration problem and you need to track that down. And if you have a V2 board, vib problems are going to be your friend with the HP06 if you don't figure them out.

[BladeScraper]

+1

I hear the WowHobbies conversions suck. I think the motor not spinning may be due to a burned ESC?

[NCcraig]

Originally Posted by BladeScraper

+1

I hear the WowHobbies conversions suck. I think the motor not spinning may be due to a burned ESC?

No. It's probably due to a bad solder joint or one of the multiple p-n-p connectors robbing power from the motor.

[BladeScraper]

If it is a bad solder joint, wouldn't it just stutter? A bad solder joint leads to stuttering, on the motor leads anyway.

OP, make sure the ESC actually works by listening if it makes a tone on startup. If you don't hear anything, you have a bad solder joint in the power connection.

[NCcraig]

Originally Posted by BladeScraper

If it is a bad solder joint, wouldn't is just stutter?

No but then we are trying to explore all the parameters of the problem. Everything is not a burnt ESC.

[BladeScraper]

read my edit.

[andrej2k]

Thanks for super quick answers guys!

Do you think the cheap CNC kit makes the vibration worse? I had the stock swash for a while, but I think the vibration was the same.

I'm not that good in soldering, as you can see on all the wires wrapped around the heli.. So, if I understand you right; I can probably fix the "no rotor spin" with some soldering? I will check out tomorrow if I can see any visual damage to the esc or the solder joints. I didn't notice anything today.

The vibration is still a mystery. Can't for the life of me figure it out. The last thing I can do is to buy a full mikroheli metal head combo kit, but because of the price tag I would rather not unless you think that's the only way to go from here

[Dylwad]

Its a V2 correct?

90° tail kick is always ALWAYS vibes. Throwing parts at it doesn't cure vibes unless you get lucky every once in a long while.

Dynamically balancing the head is the only way, brand of upgrades, type, plastic, metal whatever doesn't matter.
Spool up at 0 pitch holding the heli in your hand, check for vibes, turn the head assembly 180°on the main shaft, vibes will get better or worse, swap the blades in the grips, vibes will get better or worse. Once you find the combo of the above with the lowest vibes, start adding little pieces if tape to the blades one at a time, swapping between blades and size of tape until you literally feel no vibration in the heli.

What pinion is on your motor?
Can you take a close up pic of the esc?

V2, non flashed XP-7a and anything bigger than an 8 tooth is a bad combo for a v2, especially with a brushed tail, especially with the combo from wow with the walkera tail blade.

[andrej2k]

Yes, it is a V2.

Vibes:
I will try to balance the rotor head and blades the way you told me to, Dylwad

ESC:
I'm using 8T on the motor. About the tone at startup. That sound isn't there anymore. The little blue light turns solid when connected, and the gyro just starts working without any tone. Weird..

I don't know too much about flashing and stuff. All I know is that this was a plug and play kit, so I thought what needed to be flashed already was flashed :p

- What throttle curve should I have if I get this little bastard working again? Somewhere between 70-80%?
- Do I have to go brushless tail with the hp06?

Here are some pictures of the ESC:
http://trellaern.com/arl/1bilde.JPG
http://trellaern.com/arl/2bilde.JPG
http://trellaern.com/arl/3bilde.JPG

[NCcraig]

Your p-n-p kit is not flashed. The top board is the convertor. You can run any throttle curve you want with that set-up. Also, you don't need a BL tail with a HP06. It's nice but not necessary as a SR120 motor will work.

[andrej2k]

Thanks. So the esc looks ok? The main rotors are still not moving, but I don't know where to begin to try fix it..

[NCcraig]

Originally Posted by andrej2k

Thanks. So the esc looks ok? The main rotors are still not moving, but I don't know where to begin to try fix it..

Check all your wiring, solder joints and connections for starters.

[andrej2k]

NCcraig, as expected, you where right about the connections. The connection with the motor and the esc is not good. It slides out if I don't hold it in, and even though I'm holding it, the connection fails from time to time. I will probably have to use the plug from the c05 motor, which fits perfectly.
http://trellaern.com/arl/4bilde.jpeg

About the vibration. The rakon heli main frame is lower to give better 3D performance. I haven't found a main shaft that perfectly fit this frame, so the stock that I'm using is too long. Because of that I have to push the main gear all the way past the ... ehm... you know what I mean. I don't know the english term (see picture). Do you know if that can be a vibration factor? I can actually see that the main gear spins a bit of its axis.
http://www.trellaern.com/arl/5bilde.JPG

[jmtyndall]

The flat on the shaft you mean? You know you can file that a little longer with no negative consequences.

[NCcraig]

Originally Posted by jmtyndall

The flat on the shaft you mean? You know you can file that a little longer with no negative consequences.

Actually, I think the instructions that come with the Rakon frame state you have to file the flat part of the main shaft 2mm longer if I'm not mistaken.

[jmtyndall]

Originally Posted by NCcraig

Actually, I think the instructions that come with the Rakon frame state you have to file the flat part of the main shaft 2mm longer if I'm not mistaken.

Haven't bought one before, so I don't know, but you would certainly have vibes if the main gear isn't tight against the frame bearing.

[Raidersfoester]

A few comments/recommendations. I too bought the WOW "Steve" convertor for one of my v2's (ironically I've been buying up used v1's as they work better for BL conversions). Anyways, WOW had a decent price on their HP05s kit w/ the XP7A-5 (just under $50 w/ coupon code) so I gave it a shot. I've actually coupled it with the Extreme Turbo 8.5mm brushed tail motor/metal boom kit (same motor as the 120 SR, and the Walkera boom kit WOW sells, but like $20 cheaper). At first I had the exact same issue you had with the ESC spooling up fine, tail connected fine, servos good, etc., but minimal to no main motor movement (though you can hear the clinking like it was trying to go). I then thought maybe the main gear mesh was too tight, binding up the main. I took off the gear and the motor cranked fine (mind you this was after disconnecting the tail first). It then donned on me that the when the tail and main were plugged in together I got nada (or erratic behavior at best). The light finally went off...the 300 mAh Nano-techs I was using (which WOW says is enough juice) is not enough juice for this setup. Fortunately I had a couple of 550 mAh Hyperion and Microheli batts on the way. As soon as I plugged in those batteries everything cranked up right away, and with solid results. The tail is a tad "whippy", but I also think it may be a tad too much for the BL motor I'm using (going to try a 7mm to see how I works).

The bottom line is that when you go BL (especially above the C05), along with a large brush tail, you need to feed the beast...they need juice. It's pretty much common sense. I run my stock brushed motor and 6mm brushed tail w/ the 300 mAh LiPos and still only get 3.5-4 mins of 3D (at best). You can't expect those batteries to run not just one bigger more powerful BL main motor, let alone adding an 8.5mm tail to the mix. If you're not using a bigger battery with your new setup, there's your problem right there (at least it sounds just like mine).

As for the vibes/90-degree tail swing, I think it may be that combo of not enough juice, the v2 board (though you shouldn't have vibe issues with an HP05s or less), and I would argue that the 120SR (8.5mm tail) is overkill with the C05 motor kit you started off with, and may have explained the tail issue right there. You could likely get by with using just the stock extended boom, or at most the 7mm brushed motor with the C05 setup, which also would allow you to get by using the 300mAh batteries as well. Listen to the others about your newer BL motor setup...but I'd make sure you have enough juice.

BTW, I've done a grand total of 2 BL conversions ever, all in the last 2 months...I definitely have no clue what I'm talking about. But I did just convert using your WOW setup, and it was successful. Oh, and I stayed in a Holiday Inn Express last night.

[Arthure]

I had the same problem yesterday with my CO5M and it was most certainly vibes. I changed main blades while I changed out the bent spindle and now it is smooth as glass and the heli is rock I mean rock solid again.

No doubt it is a vibe problem.

Mine happened after I dumped it hovering inverted with TH from 10ft into a loose rock front yard. Normally the mCPX would fly away from that but broke the tail motor holder and bent the spindle.

I first tried a couple tail motors no change at all. The swapped spindle and tada.

It really wasn't that bad of a vibe at all really but I had just seen indoorheli show how he checks spindles and pulled my blade. Sure enough bent.

Funny thing is my spindle on the hP05s bird was worse but didn't kick. So I am guessing it has a lot to do with the freq of the vibe.

Arthur

[andrej2k]

Thanks for all help!

I've done a couple of changes that seems to be working for me:

I changed my new (almost unused) stock bullet blades with KBDD extreme, and the vibration was gone. I didn't know that the blades could be off balance when they where new, but the KBDD does the job. I have to order a couple more of these!

It seems like the motor have to be connected to get the startup tone. I haven't had the time to change the plug yet, so if the heli is silent at startup I know the connection to the motor is lost.

Xtreme 550mah just arrived in the mail, and these seems to be working a lot better than the 300's and 350's I got. A lot heavier, but the mcpx got a lot of power even at 70% throttle! I broke the WOW hobbies 120tail mod, and changed to a regular 120tail. This seems to work a lot better. The stock 120 tail is longer than the WOW mod. I will probably stick to this tail since I can get it from my local hobby shop.

Does anyone know what % throttle that seems work best with hp06v2, 120 stock tail and xp-7a?