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Old Oct 01, 2012, 03:34 PM
More coffee, please!
sir_clive's Avatar
Austria, Wien, Vienna
Joined Jul 2011
659 Posts
yeah, that's why I repaired and sold the damn thing. too unpredictable. besides, I actually always wanted to have a plane anyway, so here I am... and it's GOOD!
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Old Oct 01, 2012, 03:38 PM
Emress
Joined Nov 2011
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could i see it :P?
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Old Oct 01, 2012, 04:28 PM
More coffee, please!
sir_clive's Avatar
Austria, Wien, Vienna
Joined Jul 2011
659 Posts
You wanna see... what?
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Old Oct 01, 2012, 06:14 PM
Emress
Joined Nov 2011
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the pic ofc
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Old Oct 03, 2012, 09:12 AM
Cheese eating monkey.
France, Bretagne, Rennes
Joined Jul 2011
257 Posts
Quote:
Originally Posted by Wilfor View Post
Depends what you call vibrate . you could have a timing issue and need to try setting it to high . It can make a screeching sound and stop if timing isnt set .
Here is a video of my motor misbehaving:

RC brushless motor misbehaving (0 min 29 sec)


You can hear the noise that the motor makes, it is not as bad as it was Sunday while I was flying. The motor speeds up and then suddenly "stall" with a weird noise, Sunday it would sometimes not restart or even restart backward. For the synchronisation of the ESC, I've chosen the lowest setting. Also if I remove the propeller, I can't reproduce the fault.

Sunday, it was much worst, the air temperature was higher if that matters. I am not sure if that's the symptom of a mechanical or electrical fault.
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Old Oct 03, 2012, 10:22 AM
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LaGrange, GA
Joined Jun 2009
1,818 Posts
If everything was working fine before, I wouldn't think it was the timing on your ESC. I had one behaving similarly to that before, but the plane had been rammed into a brick wall once, the motor had shot out of the front of the plane once and I landed with it hanging by the wires and the motor had survived many of my "infamous landings". In *my* case, I think I had just beaten the bearings until the motor made all kind of funny noises..... It was one of those $6 CF2822's from HobbyKing so instead of worrying about the bearings, I just installed a new motor and all was well.

Originally, your motor was working fine, right? If so, I'd say it was something physical such as bearings or perhaps a magnet or two has come loose or dropped out. Sometimes the magnets come unglued which I suspect could possibly cause the motor to restart backwards. Have you taken the motor apart and inspected for loose or missing magnets? Do you possibly have a second motor you could connect and test to see if it runs right?
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Old Oct 03, 2012, 10:23 AM
AKA Don
bz1mcr's Avatar
United States, MI, Houghton Lake
Joined Dec 2002
7,650 Posts
Motor glitching

That is almost certianly an electrical problem caused by a bad connection or arching between motor leads. Arching is most likely. Darken the room and look at the wires from the esc to the motor. Watch closely near the ends of heat shrink and bullet connectors. A tiny bare spot close to another wire will allow an arch which will cause the motor to stutter. Check each motor lead and each connection. Look for any cuts in the insulation. Reheat all solder joints and apply heat shrink 4mm onto the insulation on each side of the joints. If you have bullet connectors look for any bare metal showing. Seperate all bullets from each other.
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Old Oct 03, 2012, 10:37 AM
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LaGrange, GA
Joined Jun 2009
1,818 Posts
You're probably right Don. That's a much better explanation for the running backwards as well. Panoramix, inspect everything very closely. If it's arcing, you'll probably see some dark spots in your wiring. You'll probably be able to smell it if you get down in there close. Get a magnifying glass and look real close. Probably, the easiest thing to do first would be to run your motor up in a dark room like Don suggests and you'll probably see the arcing and that'll point you to where to inspect first.

BTW, great video and I think that's a great place to fly. If it was crowded with people, maybe not, but floating a BluBaby around the way you are, wouldn't seem to pose a problem to me.

Come to think about it Don, that's probably what was wrong with my CF2822 as well. Remembering back, I think the edge of the bell housing had kind of rubbed a spot on the motor wires up close to where they went into the motor and it was probably causing a short..... being a $6 motor and the fact that I had a spare, I just replaced it instead of spending the time on it..... the old one is still in my motor box though! I'll give it a look-see sometime time.... I bet I can just slide some heat shrink up on there to repair it.
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Old Oct 03, 2012, 10:43 AM
Cheese eating monkey.
France, Bretagne, Rennes
Joined Jul 2011
257 Posts
Quote:
Originally Posted by bz1mcr View Post
If you have bullet connectors look for any bare metal showing. Seperate all bullets from each other.
I think that I've just learned something the hard way. I will check carefully later but there is a bit of metal showing off my bullet connectors, and what you say make sense. I suppose that the connectors were a bit further apart before.

Quote:
Originally Posted by JohnsPop View Post
BTW, great video and I think that's a great place to fly. If it was crowded with people, maybe not, but floating a BluBaby around the way you are, wouldn't seem to pose a problem to me.
Thank you, your support is very much appreciated as these people on the French forum really made me doubt!
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Old Oct 03, 2012, 10:44 AM
Jack
USA, ME, Ellsworth
Joined May 2008
17,222 Posts
Quote:
Originally Posted by Panoramix View Post
Here is a video of my motor misbehaving:
<snip video link>
You can hear the noise that the motor makes, it is not as bad as it was Sunday while I was flying. The motor speeds up and then suddenly "stall" with a weird noise, Sunday it would sometimes not restart or even restart backward. For the synchronisation of the ESC, I've chosen the lowest setting. Also if I remove the propeller, I can't reproduce the fault.

Sunday, it was much worst, the air temperature was higher if that matters. I am not sure if that's the symptom of a mechanical or electrical fault.
Like bzimcr says, it is almost certainly an electrical problem. I looked back through your posts but don't seem to see what you are using for a motor, prop, battery, and ESC. A list of those would be helpful.

Another good trouble shooting method is to get the motor running (prop off) at low RPM and then start wiggling each connection point between the battery and motor. Also wiggle the wires where they enter the motor a little. If you hear a change in the RPM you can usually find your problem.

If it is a problem inside the windings, where the current is jumping a gap and creating an intermittent short, that will be harder to find. But if you can rule out the other faults first, it will narrow things down.

Do you have a DMM? I'd start with seeing what the Rx1 reading are on the three motor connectors (1-2, 1-3, 2-3). If you do not get steady, low resistance, reading there it is a short to the stator or between the windings.

And it may be time to learn another rewarding aspect of this hobby, how to rewind motors!

Jack
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Old Oct 03, 2012, 10:47 AM
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LaGrange, GA
Joined Jun 2009
1,818 Posts
The good news is if the motor is still running, once you locate the problem and get the wires separated/insulated, everything should be ok with no permanent damage. You've possibly shortened the life of the motor and/or ESC, but hey.... We live and learn.
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Old Oct 03, 2012, 10:54 AM
Jack
USA, ME, Ellsworth
Joined May 2008
17,222 Posts
JohnsPop wrote:

"..being a $6 motor and the fact that I had a spare, I just replaced it instead of spending the time on it..... the old one is still in my motor box though! I'll give it a look-see sometime time.... I bet I can just slide some heat shrink up on there to repair it..."

Wait! Don't you want to get into the contest to see who can devote the most time and attention to making a silk purse out of a sow's ear? That seems to be view that some have of us guys that will buy $8 worth or wire so that they can rewind at $6 motor.

Besides, that is an $8 motor now in at least some of the venues

http://www.headsuprc.com/servlet/the...ushless/Detail

Here is a good thread on that motor over on the motor building and rewinding forum:

Rewinding Emax CF2805 & CF2822 - http://www.rcgroups.com/forums/showthread.php?t=757001

Welcome to my addiction...

Jack
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Old Oct 03, 2012, 10:59 AM
Cheese eating monkey.
France, Bretagne, Rennes
Joined Jul 2011
257 Posts
For reference, I have a
  • 10 amps ESC,
  • a bluewonder 1300kv motor,
  • a 8x3.8 propeller
  • a 1100mAh 20C battery.

This is probably way over the top in term of power, battery lasts at very least 15 minutes (so that's 4.4 amps average)
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Old Oct 03, 2012, 11:11 AM
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LaGrange, GA
Joined Jun 2009
1,818 Posts
Quote:
Originally Posted by jackerbes View Post
Wait! Don't you want to get into the contest to see who can devote the most time and attention to making a silk purse out of a sow's ear? That seems to be view that some have of us guys that will buy $8 worth or wire so that they can rewind at $6 motor.
While I do think that would be interesting and I *do* like repairing things instead of buying new things even when it's not always cost effective, as little time as I have for the hobby right now, I'll have to say "no". Yeah, I think everything, everywhere pretty much has gone up. I bought the ones I have a couple years ago. Thanks for the link though Jack, when I get a chance to take a look at the one in my box, I know where to come looking for the info.
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Old Oct 03, 2012, 11:14 AM
Registered User
JohnsPop's Avatar
LaGrange, GA
Joined Jun 2009
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Quote:
Originally Posted by Panoramix View Post
This is probably way over the top in term of power, battery lasts at very least 15 minutes (so that's 4.4 amps average)
I think that's the exact setup I had in my original BB33. It wasn't too much power on the last day it flew as my son got too far downwind and couldn't get back out from over top of the the trees before we lost it in the tree-tops. Ok, maybe it *was* too much power, and we just shouldn't have been flying in that much wind. Anyway, I think that's a good combo for the 33.
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