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virtual
02-12-2007, 08:27 AM
Hi. I'm fairly new to the RC world. i'm wondering...i've recently put together a super sportster mini...i got a new motor, a brushless outrunner of 1250 KV. and a 8x9 prop to go with it..when running the 8x9 prop, the motor didnt get get hot at all, only a little bit warm. but i tryed the prop that came with it. it was quite alot bigger and after running the motor with it, just testing not flying, the motor got very hot almost burning my fingers, running at about half throttle witha few bursts to full. My question is, is it bad for the motor to get very hot, or is it ok ? wats the normal running temp for a motor.

k-vette
02-13-2007, 06:40 AM
The motor should not get hot, especially if it's an outrunner and you're touching the outside. If you have a way to measure the temp it should be done on the wire inside of the motor. The best way to know if you're overloading the motor is to measure the current. If you state the exact model of the motor and the battery you're using some guys on here might be able to tell you the ideal prop setup.;)

virtual
02-13-2007, 07:49 AM
Well, its an ST model 1250kv outrunner...so it shudnt get hot at all ? is warm ok ?

thanks for your reply

rea59
02-13-2007, 02:22 PM
Well, its an ST model 1250kv outrunner...so it shudnt get hot at all ? is warm ok ?

thanks for your reply

I would need more info on the motor to determine the exact problem. (IE: windings, etc)

Does the ST stand for Storm motors? If so these would be the details.

Storm 35-42-1250KV Brushless Outrunner Motor. High Performance motor for 21 to 67 ounce aircraft. Weight 4.47 ounces. For 3s 11.1v LiPo or 4s 14.8 Lipo shaft size 4mm, dimensions 35x42mm, RPM per volt 1250, recommended props 11 x 8 for 10 cells or 3s Lipo, 10 x 4.7 4s Lipo 45 amp or higher brushless ESC. Over 540 Watts.

ScubaSteve
02-13-2007, 08:30 PM
Is that your motor? How big is the prop that came with it?

virtual
02-14-2007, 04:07 AM
no, ST Models is some chinese brand :S i didnt know much about RC when we bought it, we just took the one the hobby guy said would work :P he gave us a 8x6 prop to go with it, lots of pitch.

It runs fine with that, but i ran a bigger prop on it, much bigger, and it got rly hot rly fast.....i'm wondering how hot is too hot for it to be running

ScubaSteve
02-14-2007, 02:45 PM
HOT period is too hot. Do you have a temp gun? I wonder exactly how hot your motor is.

jdetray
02-15-2007, 06:45 AM
In addition to possibly melting the insulation on the windings, excessive heat can also reduce the strength of the magnets, effectively ruining the motor. It depends on the temperature rating of the magnets, of course, but "too hot to touch" is often too hot for the magnets.

- Jeff

virtual
02-15-2007, 07:43 AM
ok, well it wasnt near that hot i dont think, but an outrunner, shud it always be running cold ? shud it get warm at all ? and if it does get warm does that mean the prop is too big ?

jdetray
02-15-2007, 07:50 AM
It's fine for an outrunner motor to be warm. As long as you can comfortably hold it in your hand, it is probably fine.

- Jeff

virtual
02-15-2007, 07:56 AM
ok kool :) a sad day for me yesterday....i crashed due to the stupidest thing in the book. The radio aerial wasnt pulled out :( my god i nearly cryed. the front took all the damage, motor mount broke, and the front is all kinda smashed up inside. :(

ScubaSteve
02-16-2007, 03:06 PM
Repairable? Tis not all lost - at least you learned something, right?:)

virtual
02-18-2007, 08:22 AM
eh, probly repairable...with a lil firbreglass matting, but decided to just buy a new plane.. i finished building today, and its better than the first, due to my prior experiecne. Also got the nxt prop size up, a 9x6, hopefully will get a lil more vertical power. i'll let you all know how the maiden goes :)

virtual
02-21-2007, 03:42 AM
well the maiden went just fine, i had 2 batterys but it was gettin a lil windy so i decided to call it a day. altho it flys very nose heavy...but the COG test shows its balanced, anyideas?