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Old Mar 23, 2014, 09:55 PM
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Motor smoked...I messed up

Hey , it's been awhile.........getting back to flying....glad to be back....hello....I smoked a cheap...BM2408-21....and using a "Thunderbird-18.....2 cell was fine but tried 3 cell bat and there came smoke from motor...think was motor or ESC?..........was on PT17GWS Stearman.....man was depressed................wadayathink?....I think was motor?......Thanks.......Guess I messed up on ESC and motor............Thanks for taking time to check out post...........

Dale
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Last edited by highpines; Mar 23, 2014 at 09:58 PM. Reason: Typing
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Old Mar 23, 2014, 11:42 PM
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Mark Wood's Avatar
United States, CA, Bear Valley Springs
Joined Feb 2000
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Neither motor or ESC...prop.

mw
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Old Mar 24, 2014, 03:48 AM
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Letchworth, Great Britain (UK)
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+1

The amount of amps any particular motor draws depends almost entirely on supply voltage and prop size. If you increase the volts (battery cell-count) you must normally reduce the prop size to ensure that the amps stay within the motor's and ESC's limits.

If you check out the motor's spec http://www.raidentech.com/bmoubrmowfim.html you'll see that they suggest 9x4 prop with 2S or 8x4 prop with 3S. Since different brands and styles of prop perform differently, you should check the actual amp draw with a wattmeter when you change props, to ensure that you're not exceeding the motor's or ESC's amps spec.
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Old Mar 24, 2014, 04:44 AM
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Thanks guy's

Like said been away for a couple years....how easy to forget.....right? ....Thanks for the help on props. guess used to huge prop on S/S and 3 cell.......I was just excited to get her up....had one before I like low and slow. I have a Superfly and a Beaver GWS and my S/S....but wanted to get this Stearman in the air....fun plane....Here in snow jjust getting ready to fly...after all melts in Utah.......
I have 3 more motors, tons of props.....prolly ask more questions if you don't mind......
Thanks;;;;;D
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Old Mar 24, 2014, 09:57 AM
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USA, AZ, Gilbert
Joined Jan 2006
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Tell us the motor you plan to use, link us to the online store, post kV of motor and battery cell count you will use and we can help you with prop size or tell you to use another motor...

Rick
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Old Mar 24, 2014, 07:59 PM
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Thank you

It's an eflite 480......say's 910Kv and to use a 10-7 to 12-6 prop.......I'm afraid of course like last time to smoke her out....No need to go crazy.....I like low and slow ...Here's the specs...I can get close i'm sure....Hope ESC is OK but can rob from other planes.....just hope this 2 s will put her in the air......thanks again for all your help....ohhhh say's wants 20-30 ESC.....is that a prob?...mine are 18amp

Got more props that I know what to do with shouldn't be a prob....and 3 cells, small and big but now they scare me.......can't afford.....just want to fly right?

here's link

http://www.ebay.com/itm/E-flite-Park...item43b4a47e21

Thans again!!!
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Last edited by highpines; Mar 24, 2014 at 08:03 PM. Reason: forgot
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Old Mar 25, 2014, 03:34 AM
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Letchworth, Great Britain (UK)
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Quote:
Originally Posted by highpines View Post
It's an eflite 480......say's 910Kv and to use a 10-7 to 12-6 prop.......I'm afraid of course like last time to smoke her out....No need to go crazy.....I like low and slow ...Here's the specs...I can get close i'm sure....Hope ESC is OK but can rob from other planes.....just hope this 2 s will put her in the air......thanks again for all your help....ohhhh say's wants 20-30 ESC.....is that a prob?...mine are 18amp

Got more props that I know what to do with shouldn't be a prob....and 3 cells, small and big but now they scare me.......can't afford.....just want to fly right? ...
Note that the spec says it's good for 7.2v to 12v batteries (effectively 2S or 3S), so the larger prop they suggest is for the 2S battery, and the smaller one is for 3S. If you use the larger one with 3S you'll smoke another motor

The spec also says the motor is good for 20A. Normally I would put a prop on that makes it draw 20A (why waste power if it's available) and get an ESC that's good for 25A or more. But if, say, 15A is going to give you enough power (so as not to overload your 18A ESC) you could put a smaller prop on to keep the amps below 15A. Once you've chosen the battery voltage, the amps depend only on the prop size, so that's where you need a wattmeter so you can see what's happening when you experiment with different props.
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Old Mar 27, 2014, 02:29 PM
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Thank you all so much...yep 2 s and smaller prop..never a prob...heck the 3 s and using 10.7 is what smoked motor. I have wat meter in tool box somewhere will check....I think I'm starting to remember how it all works......right now just waiting for snow to fade away......just getting ready to fly again......Like said have Superfly Gws Beaver and a slow stick with 3s and vertical no prob....fun planes..
..thanks again
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Old Mar 28, 2014, 10:00 PM
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Thanks again........Job interviewing and trying to get these planes ready.....kind of a pain.....I'll keep you updated if o.k....
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