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Electric Stunt => Gettin all AMP'ed up! => Topic started by: RC Storick on October 19, 2015, 09:09:21 AM
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After this is answered I will move it to electric section.
Question is has anyone used this motor http://www.hobbyking.com/hobbyking/store/__14400__Turnigy_G32_Brushless_Outrunner_770kv.html
with a 5 cell battery? The KV is right but specs say use up to a 4 cell.
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While you're waiting for a real answer:
First, I think they're cracked. Or just blindly copying from a prior data sheet.
Second, I'm too lazy to check, but the subject of running motors at above-rated cell count has been treated in the electric section. It's generally considered kosher for two reasons: one, because if you're governing the RPM the motor will, more or less, always see a lower voltage, and two, because electric motors can generally be run at considerably higher-than-datasheet voltages with only accelerated wear on the bearings* to show for it.
* Well, accelerated wear on the bearings and if you push it too hard bursting apart dramatically, leaving bits of motor all over the room. A coworker of mine used to work at a motor company doing tests on their bleeding-edge product line. For a while his job was, basically, to explode brushless motors. You don't have to worry about this unless you go something like 2x or 3x the recommended cell count AND run the thing WOT with no prop.
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A coworker of mine used to work at a motor company doing tests on their bleeding-edge product line. For a while his job was, basically, to explode brushless motors. You don't have to worry about this unless you go something like 2x or 3x the recommended cell count AND run the thing WOT with no prop.
The real problem we have with high RPM is not explossion, but resonance. Every motor has some rpm when the rotor resonantes. Motor of this type (ourunners) has that resonation close to our rpm. So it sometimes resonates - you can hear it as a "metalic noise" and it will soon make free play in bearing which will lead to loud screaming at particular RPM when free play is so large that it can make such sound, but is already too late to solve it.
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The real problem we have with high RPM is not explossion, but resonance. Every motor has some rpm when the rotor resonantes. Motor of this type (ourunners) has that resonation close to our rpm. So it sometimes resonates - you can hear it as a "metalic noise" and it will soon make free play in bearing which will lead to loud screaming at particular RPM when free play is so large that it can make such sound, but is already too late to solve it.
Dan was working on motors designed for high speed, so presumably that was dealt with. And, to be more honest than dramatic, they were inrunners so the usual failure mode was that the magnets would come unglued from the rotor, expand into the stator, and much smoke, but little metal, would be emitted.
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Robert,
You should not use it outside of what is recommended.
The electric setups no matter how cheap or expensive have their recommended usage for a reason. Go outside of that and you invite disaster.
Proceed at your own risk. Is it worth risking your model over $30 motor? Only you can answer that one...
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This is for my scale shoestring and I ordered it as it was cheap. I don't need the power control like a stunt plane. I will give a report on how it works and how long it lasts.
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If you look down the comments section on your link someone asked the same question you are asking.
One person said it can handle 5s but to be careful as you could pull too many amps.
What size battery are you going to use, mha and c rating? What size ESC are you using?
I saw the flight video. Very cool looking plane!
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Hello Robert,
When we use a motor for Stunt, we are nominally running it at somewhere between 70% and 80% voltage so that it governs.
If the manufacturer says 4S and you govern it at 75% of the 5S voltage, you will be running a little less than 4S!
Don't worry.
As always, too much prop means too much current and a fried motor, but there is no news here.
Do you have a way the measure the current? I found a great clamp-on DC ammeter from Sears a while back.
How heavy and large of a ship do you plan to fly with this motor? Then I will go look at that website, just to make sure.
take care,
Dean P.
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I have one of those and run it on 5S. The bearings went out in about ten flights, which I'm pretty sure, had nothing to do with the batteries, just lousy bearings. The Castle data logging looked just like the E-flite 32 info, at least until the bearings made things ugly. There was one locally on an Impact. Worked fine.
I have new bearings from Boca but haven't tried it yet.
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Hello Mike,
It sure does look like an E-Flite Power 32 clone as well.
Did you have yours mounted at the nosering or was it firewall mounted?
Many motors do not tolerate Stunt use with firewall mounting.
Thanks,
Dean P.
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I sometimes treat the Chinese stuff as a kit that just needs disassembly before you can get down to the real work of putting it together. They generally seem to do well at the stuff that makes a part look like what it's supposed to, then fall down on the price critical stuff.
I wouldn't be surprised at a Chinese motor that works just fine after the bearings are replaced by something up to snuff.
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Dean, the mounts (bolt circle) are the same as an E-flite power 25, although the physical size is 32. It took the place of a Plettenberg 20-16, front mounted. I think I agree with Tim, good bearings will be an improvement. I was going for the Kv and weight comparison. The airplane is set up for 5S and the power 25 wouldn't hack it. The Plett is OK, but only 710Kv (?) and heavier. I would have gone for a Power 32 but it wouldn't fit in the allotted space.
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Applying 6S in a motor designed for 5S and see that the temperature did not increase much.
https://www.youtube.com/watch?v=3goYI8zzyTs
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I haven't used the Turnigy G32, but I did buy a G25 870kv(looks just like the Eflite Power 25). When I got it I found it only has 10 magnets instead of the 14 the Power 25 has. Someone with more knowledge might know what the lack of magnets will do to the motor operating characteristics. The parts are not interchangeable with the 2 motors can length is longer on the G25, and the bell ends are machined differently on the inside where they seat against the bearings.
Bob
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I haven't used the Turnigy G32, but I did buy a G25 870kv(looks just like the Eflite Power 25). When I got it I found it only has 10 magnets instead of the 14 the Power 25 has. Someone with more knowledge might know what the lack of magnets will do to the motor operating characteristics. The parts are not interchangeable with the 2 motors can length is longer on the G25, and the bell ends are machined differently on the inside where they seat against the bearings.
Bob
If all else were equal then the 10 magnets vs. 14 means, I think, and for the most part, that the motor will vibrate a bit more.
But "All else is equal" isn't a good assumption when you're comparing cheap Chinese vs. name brand (eFlight probably has their motors manufactured in China, but they probably ride herd on the QA fairly hard -- unless things have changed in the five years that I haven't been looking, that's how an importer gets good stuff from China).
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This is for my scale shoestring and I ordered it as it was cheap. I don't need the power control like a stunt plane. I will give a report on how it works and how long it lasts.
Thanks Robert,
That makes sense.
Dean
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I use the G series motors. Great motors for the price. Do not rear mount them (same as any larger electric motor) and use the Trust esc and you are gold.
Warren
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I've had E-Flite 32 bearings go south, too.
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Randy, was the motor front or rear mount?
Warren
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I was a front mount. The one I have on rear mount is fine. E-Flite's are odd that way. Paul Walker was telling me that he had one E-Flite 32 that has lasted more than a 100 flights and works fine. Another one, the bearing went out after 10 flights. I've had the same experience. I suppose it depends on their bearing suppliers. I changed out the one the bearings went out on and it seems to work fine again. We'll see how may flights it goes.
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Interesting.. and I thought my bad experience with the E-flite 32 was an isolated case. As my first 32 lasted only 9 flights. I notice the bearing was a bit grungy on the 3rd flights on.. sort of reminds me of my Saitos when I didn't put after run oil in for a few week after flying. mine went and it burned up something inside as well.. because I bought it 3 years ago, I had no warranty. HB~> But my new 32 has 30+ flights so far and is still smooth and both were front mounted.
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Need to correct this...
quote author=Randy Powell link=topic=41057.msg423354#msg423354 date=1446575526]
I was a front mount. The one I have on rear mount is fine. E-Flite's are odd that way. Paul Walker was telling me that he had one E-Flite 32 that has lasted more than a 500 + ( yes, 500, not 100) flights and works fine. Another one, the bearing went out after 50 ( at least 50, not 10) ( a Cobra rebearing lasted only 10 flights) flights. I've had the same experience. I suppose it depends on their bearing suppliers. I changed out the one the bearings went out on and it seems to work fine again. We'll see how may flights it goes.
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Thanks for the correction, Paul. I had thought you were commenting on the E-flite. Thanks.