View Full Version : Newbie with new motor trouble

05-25-2008, 04:58 AM
I purchased a new BM2410-08 motor, 10x47 prop and mag 8 tower pro esc combo from hobbycity for my Edge 540BP. When I fire up the motor with no prop everything seems to be fine. When I install the prop and throttle it up, the motor starts making a bad noise and everything stops at about 40% throttle and the motor gets warm quickly. I appears that the coil part of the motor may be turning slightly when under thrust and throwing the timing off? I can grasp the coil and it rotates slightly quite easily. I also have end play on the prop shaft. Is this normal? The prop seems to be balanced fairly well, so I don't think that is the problem. Can these motors be disassembled and the coil secured so that it doesn't rotate? This motor has not yet been flown so it is not damaged.

05-25-2008, 05:11 AM
Not exactly sure what you are referring to. These motors are not difficult to take apart. Here's a diagram (http://www.bphobbies.com/pdf/bp/BPMotorDisassembly.pdf).

That said, these packages really are cheap. I started out with a similar motor and the TP ESC and now that I've learned a bit more will never use them again. Motors are wound with 4 tiny wires and they can be broken right out of the package (had this happen) and break spontaneously from just normal flying vibration. The symptoms you are having seem indicitive of a poor connection or broken wire. So look for those kind of problems. Pretty low quality bearings also.
ESC's have more questions on how to use and program them than any other type in the forum. They won't handle nearly the Amps they are claimed to most of the time.

05-25-2008, 04:01 PM
THanks . the diagram on that page answered my question on the motor securement. The screws holding the stator to the motor mounting flange were loose. I tightened them, and it helped. My motor still makes a racket and comes to a stop at nearly full throttle now. How does the motor brake work? It sounds as if the motor is braking it self. Nothing is rubbing and I can see no reason for the noise. The motor is quiet at full throttle with no prop. It will always restart when I throttle down and then throttle up again. I've most likely got a bad motor as you suggested. I actually bought this motor/esc/prop combo because of good reviews given here at wattflyer about the price and quality of hobbycity motors. And I can also see why there are questions about the timing and braking options on the tp esc. The directions are nearly given in piglatin at best, on the setup

05-26-2008, 03:52 AM
When I bought my first TP motor/ESC combo and got out of brushed I thought I had found a near miracle. Much better performance and hardly any cost penalty at all. There are hoards of cheap/new fliers discovering the "toys" at HC everyday and ecstatic about the low prices. Yes, I've been there too. In an evolution of only a few months I've gone from a very happy pilot with a new discovery to a much more jaded one after those same toys started failing at a pretty alarming rate. It's not just me. I fly with a local group of guys that have had a similar change over the fairly recent past. They aren't that cheap if you have to replace them 2-3x, especially if the failure takes a plane down with it. You begin to see the value in reliability after awhile.
While you are still dorking planes it's much more palatable to do so with a $10 motor than a $70 one. At that stage you can hardly tell the difference anyway. Later you get a more judicious.

Can you get a good really cheap product? Yep. Can you get a really good cheap product? Less likely. There are a few gems in the rubble, but there is a lot of rubble.
What's the chance of getting a poor one or complete garbage? Fairly high.
What's your recourse? Pretty much nil. Not worth the hassle or cost.

The brake stops the motor when you turn OFF the throttle. It has NO function at even low throttle. It is mostly useful for glider pilots with folding props, generally not used by regular RC most of the time.

You most likely have a bad motor. You could have a bad ESC. You could have both.
How good do you think quality control was if screws were loose out of the package?

05-26-2008, 04:19 AM
Here's some more 'data' for you:

FYI, Dr. Kiwi is the main guy that does a HUGE amount of motor testing for RCGroups. If ANYONE knows motors, he does. He's a good man to get to know and find data about motors you are interested in from that forum. I've learned a huge amount there and continue to do so.

Dr Kiwi
05-26-2008, 04:32 AM
It will always restart when I throttle down and then throttle up again.

This suggests that your pack is not up to providing the required amps, without the voltage dropping below LVC.

From data I've seen that prop on that motor on 3s might well be trying to draw 11A or more - too much for your ESC. Try a smaller prop.

05-26-2008, 04:51 AM
I have ordered a new 30 amp esc, and will get a new 450 outrunner for this plane. Thanks for the help. I will experiment with the esc and motor, and try to figure out which is bad, if not both. I'll just chalk it up to experience. It's only money. lol

05-26-2008, 05:00 AM
What brand motors do you recommend as good quality with reasonable costs? I have read posts condemning eflite, turnigy, etc. Help me out with your experience. I don't like learning the hard way.

05-26-2008, 05:14 AM
I don't like learning the hard way.

You sure you're in the right hobby? Seems everyone in this sport has to learn the hard way. :silly:

A step up from the TP, seems to be the Suppos, slightly higher cost, noticeably better motors.
eflites are generally good but cost like a better motor than they are I think. I only buy them used but there are other risks with that.
Some people seem to be jumping on the Turnigy motor. No personal experience. Go find a couple motor threads and start reading.

I don't have a lot of experience with a range of motors yet, only a few. A number of those first few were the TP's so I'm giving you that cautionary info.
The groups are like collective wisdom, there are a lot of votes, often many in both camps, but if you start coming up with a better than 70-80% approval rating it bears paying attentions to.

05-26-2008, 05:43 AM
It seems all I've been doing the last couple of days is reading posts. I have learned quite a lot about electric flight. This hobby should be quite a bit less costly than many others I'm involved in. If you ever feel the need to go fishing in Minnesota, look me up. That hobby only costs several thousand a year. lol.

05-29-2008, 09:08 PM
Just like fishing in Alaska. Hey, but where else can I sit out at 11:00pm and watch the sun set by a campfire and fry a freshly caught Salmon? But I like Minnesota, though...and how strange, you and I are from a town of the same name. I was raised in Ironton, Ohio!

I do understand about reading a lot to stay on top of things. But we all still make mistakes, I cooked two of my towerpro motors due to an oopsie. But, I rewound them and made better motors out of them, anyway. I've had some really great flights on the one currently installed but I'm only fairly pleased with their performance. I'm jumping on the Turnigy bandwagon, should have a few of those soon.

I would recommend two things, though. Get a wattsup meter first. Get a good safe charger if you're going lipo. The wattsup will save you money, and the safe lipo charger might save your life. Keep reading, reading, reading!

Personally, I don't see how that setup could work without burning something up (without a wattsup). When I rewound my Towerpro 2412 to make it a 9 turn, I used 22ga magnet wire. This "new" motor pulls about 24-26amps (on my poor little 18amp ESC) with a 9x(4.6?) prop. If that's an 8amp ESC that you have...turning a 10" prop, that thing should be way over the limits of that 8amp ESC.
Like Kiwi said, try a smaller prop.

Kiwi is King!

05-30-2008, 12:16 AM
My wife thinks ALL I do anymore is RC and read about RC. I do spend too much time in the forums. But, it's entertaining and sometimes I learn things and occasionally (very) I pass something of interest along.

Fishing! Now that's a hobby from long ago. The $$$$$/inch just doesn't add up.

05-31-2008, 03:18 AM
I tried a smaller prop from hobbyzone, but it's hard to put those props on a threaded tp shaft. The collet adapter doesn't tighten securely, and the set screw adapter leaves it slighty off center so that the engine makes even more noise and shuts down almost immediately. By the way, the mag 8 tower pro esc I was using is 18 amp. Don't know why they call it "Mag 8". I have a turnigy motor coming, as well a 30 amp esc. I will take shotgunsmitty's advice and check the actual amperage draw on this motor. I have a very good dvom that will handle 0-10 amp through series connect and 1000 of amps through an inductive clamp that I use for automotive diagnostics. The town of Ironton I live in is on the Cuyuna Iron range. There has been no mining done here since 1980 and all the open pits have been turned into trout lakes. I can now fish where I once fueled ore moving equipment 300 feet below ground level. The overburden piles have all grown over and the trees are now 30 feet tall on what was once barren ground. This area is now a state park, with paved biking and hiking trails. Come and visit some time.

06-02-2008, 06:13 PM
Sounds like your Ironton is a lot better than mine. Mine was established in the 1800s and the surrounding area was littered with steel mills. There's only one that remains, and only a few places where the history is visible in the hills. The town is full of history, being an Ohio River town and a good hub for the railroads. All the lakes that were exposed after the strip mining have too much sulfur and limestone to support life, so as kids we used to go swimming, but no fishing, unfortunately. All the strip mined areas are beautiful forests, now, in what seems like better shape than they were before they were mined. Go figure.

Let us know what the amp draw is on that, I'm curious to know.