Black Dragon Vibration?

Sumpy · 06-23-2012, 11:58 AM

Hey everyone!

I installed a BD motor on my mCP X, and am noticing some fairly strong high frequency vibration. I'm running the OverSky 10A ESC w/ signal wire soldered direct to the 3-in-1. When spooling up the motor with main gear off, there is a very strong vibration - very high frequency. It's bad enough that your fingers will go a little numb holding the LG while its running.

I've tried all three of the timing settings for the ESC, and it seems like the "high" setting works best. On the "low" setting the motor did seem to vibrate less, but was cutting in and out. On the "medium" setting it didn't cut out as bad, but still did occasionally. On "high" it doesn't seem to cut out at all.

Is it normal for these little brushless motors to have this much vibration? I had been noticing how loud my heli got after installing the motor, but just now traced it down to vibration. I've attached a video to show how loud it is since the upgrade.

YouTube

Hoghunter7mm · 06-23-2012, 12:14 PM

Wow..dont think mine's quite that loud. I do notice some vibes in the heli, especially if I dont keep the blades very well balanced.

Sumpy · 06-23-2012, 12:22 PM

Yea, it's pretty loud. So loud that now I'm not sure about flying it at RV parks when we're on the road.

The motor screams with high-frequency vibration @ 100% throttle with the main gear off, so the source of the noise isn't the head or blades.

motoracer5 · 06-23-2012, 12:27 PM

http://helifreak.com/showthread.php?t=259335&page=3

post 27

Some of these little motor are quite out of balance. This procedure worked well for me. Little bit more difficult on a MCPX, but it works!

Sumpy · 06-23-2012, 12:32 PM

Quote:

Originally Posted by motoracer5

http://helifreak.com/showthread.php?t=259335&page=3

post 27

Some of these little motor are quite out of balance. This procedure worked well for me. Little bit more difficult on a MCPX, but it works!

This is great - thank you for the link! I was pondering on ways to balance the bell, but couldn't quite figure out how to do it. I'll give this a shot later today.

Hoghunter7mm · 06-23-2012, 12:33 PM

Thx for the link!

everydayflyer · 06-23-2012, 02:28 PM

I just checked my BD and it is way ou of balance. Now all I have to do is get moviated enough to take it off the frame remove the pinion and balance it. Would not be surprised if that is not the reason my is so much slower than my son's.

IMO the correct way to balance it is to add weight to the inside of the bell between the magnets. That is the way the custom motor builders do it and back in my slot car motor building days I balanced armatures by drilling and or grinding.

Next motor I will check it's balance before installing it, that is is I can remember to .

Sumpy · 06-23-2012, 09:51 PM

I tried balancing the motor tonight, but was unsuccessful. The marker trick worked perfectly, leaving me about 15% or so of the bell marked on one side. I added tape to the other side, and tried again. More tape, and again. More tape, and again. After 7 or 8 layers of tape, it was clear the vibes were getting ever so slightly less severe, but were still enough to vibrate the 3-pin motor plug loose within a minute of running. This amazes me, as the 3-pin plug is very tight to pull apart by hand.

At this point, I'm beginning to think I may have a bent shaft, or a motor so badly out of balance that no amount of tape is going to fix it. I've had no crashes since the upgrade, so the motor came out of the factory like this. I've emailed Dylan for advice, so hopefully this will all work out.

For the moment, I think I'm going to go back to the C05.

Hoghunter7mm · 06-23-2012, 11:20 PM

Good luck on that. It also crossed my mind that the shaft could be bent/warped to get that much vibes. Dylan will make it right.

Dylwad · 06-24-2012, 03:55 AM

We know about the problem, I checked every BD motor before shipping, and made a pile of the ones with the worst vibes and set it aside, and used my judgment on the rest.

The C05's are the same way, but not as bad as the black dragons % wise on the first batch. They use far too much epoxy between the magnets on the BD motors, there should be none visible just like on the Oversky or AEO motors.

Ill take care of you on a replacement. So far with the bad BD motors I have left, I have barely broken even on selling them....Bockman is stepping up and making things right though, he's just waiting on his next batch of them to come in.

Really too bad, the samples I had before stocking them were great, now I'm concerned....Sure wish Oversky made a 13500KV HP04S for $24!

Yours sounds BAD though, I dont know how it got through my QC to be honest!

BD on left, C05M middle, HP06V2 on the right.

Dylan

Dylwad · 06-24-2012, 04:00 AM

Oh, and BTW you can put the C05 magnet bell on the BD stator, direct fit and ends up the same KV.

Dylan

Hoghunter7mm · 06-24-2012, 10:49 AM

And we'll call that one the red dragon

Sumpy · 06-25-2012, 01:08 AM

Red Dragon it is!

I swapped the bell from the C05 to the BD motor, and the difference was staggering to say the least. The entire helicopter is as smooth as can be now, and all of the motor vibration is completely gone. I must have had a very well balanced C05!

I no longer have to worry about flying in public, as it is barely audible since the swap! I'll try to shoot another video tomorrow to illustrate what a difference a nice balanced motor bell makes. Everything just sounds and seems so smooth ...

Dlyan has taken care of me as well, as he always does! It is great to have a resource like him for the mCPX community. Kudos!

Hoghunter7mm · 06-25-2012, 01:21 AM

Right on..glad you got her up and running

everydayflyer · 06-25-2012, 05:16 AM

Had a go at rebalancing mine yesterday. It is better but I grew tired of waiting on batches of JB Weld to cure.

Used the curing times to convert from P nP to hard wired to see how much weight I could save. Droped 2.4 grams or 5% which is a great deal for this little bird.

Nice to know the CO5 bell works and I may get ambitious enough to do such a swap myself if latest efforts prove to provide less satisfactory than desired. Wish I had access to a 50K dynamic balancer. Wonder if it would be worth the effort to push the shaft part way out the top and static balance on a pair of razor blades mounted to a block of wood?

Sumpy · 06-25-2012, 10:57 AM

Quick video illustrating the sound level difference after the swap. I used the wide-angle lens this time since it was going out of the frame in the last video. the distance to the camera is the same.

YouTube (Short URL)

jmisuraca · 06-25-2012, 08:18 PM

Quote:

Originally Posted by Dylwad

Oh, and BTW you can put the C05 magnet bell on the BD stator, direct fit and ends up the same KV.

Dylan

Nice idea. As mine has the same noise issue but not as bad. I do have a c05 that I could swap the bell with.

Sent from my iPhone using Tapatalk

06-24-2012, 03:55 AM	#10
Dylwad Registered Users Join Date: Mar 2007 Location: Phoenix AZ	We know about the problem, I checked every BD motor before shipping, and made a pile of the ones with the worst vibes and set it aside, and used my judgment on the rest. The C05's are the same way, but not as bad as the black dragons % wise on the first batch. They use far too much epoxy between the magnets on the BD motors, there should be none visible just like on the Oversky or AEO motors. Ill take care of you on a replacement. So far with the bad BD motors I have left, I have barely broken even on selling them....Bockman is stepping up and making things right though, he's just waiting on his next batch of them to come in. Really too bad, the samples I had before stocking them were great, now I'm concerned....Sure wish Oversky made a 13500KV HP04S for $24! Yours sounds BAD though, I dont know how it got through my QC to be honest! BD on left, C05M middle, HP06V2 on the right. Dylan Attached Thumbnails

06-25-2012, 01:08 AM	#13
Sumpy Registered Users Thread Starter Join Date: Jul 2011 Location: Tennessee, USA	Red Dragon it is! I swapped the bell from the C05 to the BD motor, and the difference was staggering to say the least. The entire helicopter is as smooth as can be now, and all of the motor vibration is completely gone. I must have had a very well balanced C05! I no longer have to worry about flying in public, as it is barely audible since the swap! I'll try to shoot another video tomorrow to illustrate what a difference a nice balanced motor bell makes. Everything just sounds and seems so smooth ... Dlyan has taken care of me as well, as he always does! It is great to have a resource like him for the mCPX community. Kudos! Attached Thumbnails

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06-23-2012, 12:14 PM	#2
Hoghunter7mm Registered Users Join Date: Jul 2010 Location: Nor Cal	Wow..dont think mine's quite that loud. I do notice some vibes in the heli, especially if I dont keep the blades very well balanced.

06-23-2012, 12:22 PM	#3
Sumpy Registered Users Thread Starter Join Date: Jul 2011 Location: Tennessee, USA	Yea, it's pretty loud. So loud that now I'm not sure about flying it at RV parks when we're on the road. The motor screams with high-frequency vibration @ 100% throttle with the main gear off, so the source of the noise isn't the head or blades.

06-23-2012, 12:27 PM	#4
motoracer5 Registered Users Join Date: Mar 2012 Location: Nakusp	http://helifreak.com/showthread.php?t=259335&page=3 post 27 Some of these little motor are quite out of balance. This procedure worked well for me. Little bit more difficult on a MCPX, but it works!

06-23-2012, 12:33 PM	#6
Hoghunter7mm Registered Users Join Date: Jul 2010 Location: Nor Cal	Thx for the link!

06-23-2012, 02:28 PM	#7
everydayflyer Registered Users Join Date: May 2009 Location: Haralson County GA USA	I just checked my BD and it is way ou of balance. Now all I have to do is get moviated enough to take it off the frame remove the pinion and balance it. Would not be surprised if that is not the reason my is so much slower than my son's. IMO the correct way to balance it is to add weight to the inside of the bell between the magnets. That is the way the custom motor builders do it and back in my slot car motor building days I balanced armatures by drilling and or grinding. Next motor I will check it's balance before installing it, that is is I can remember to .

06-23-2012, 09:51 PM	#8
Sumpy Registered Users Thread Starter Join Date: Jul 2011 Location: Tennessee, USA	I tried balancing the motor tonight, but was unsuccessful. The marker trick worked perfectly, leaving me about 15% or so of the bell marked on one side. I added tape to the other side, and tried again. More tape, and again. More tape, and again. After 7 or 8 layers of tape, it was clear the vibes were getting ever so slightly less severe, but were still enough to vibrate the 3-pin motor plug loose within a minute of running. This amazes me, as the 3-pin plug is very tight to pull apart by hand. At this point, I'm beginning to think I may have a bent shaft, or a motor so badly out of balance that no amount of tape is going to fix it. I've had no crashes since the upgrade, so the motor came out of the factory like this. I've emailed Dylan for advice, so hopefully this will all work out. For the moment, I think I'm going to go back to the C05.

06-23-2012, 11:20 PM	#9
Hoghunter7mm Registered Users Join Date: Jul 2010 Location: Nor Cal	Good luck on that. It also crossed my mind that the shaft could be bent/warped to get that much vibes. Dylan will make it right.

06-24-2012, 04:00 AM	#11
Dylwad Registered Users Join Date: Mar 2007 Location: Phoenix AZ	Oh, and BTW you can put the C05 magnet bell on the BD stator, direct fit and ends up the same KV. Dylan

06-24-2012, 10:49 AM	#12
Hoghunter7mm Registered Users Join Date: Jul 2010 Location: Nor Cal	And we'll call that one the red dragon

06-25-2012, 01:21 AM	#14
Hoghunter7mm Registered Users Join Date: Jul 2010 Location: Nor Cal	Right on..glad you got her up and running

06-25-2012, 05:16 AM	#15
everydayflyer Registered Users Join Date: May 2009 Location: Haralson County GA USA	Had a go at rebalancing mine yesterday. It is better but I grew tired of waiting on batches of JB Weld to cure. Used the curing times to convert from P nP to hard wired to see how much weight I could save. Droped 2.4 grams or 5% which is a great deal for this little bird. Nice to know the CO5 bell works and I may get ambitious enough to do such a swap myself if latest efforts prove to provide less satisfactory than desired. Wish I had access to a 50K dynamic balancer. Wonder if it would be worth the effort to push the shaft part way out the top and static balance on a pair of razor blades mounted to a block of wood?