Chocky

Can someone please tell me what all the numbers refer to that are stated for a brushless motor? Just out of curiosity really, although I'm intending to buy a Wattage Crazy 8 and would prefer to install a brushless rather than brushed motor and figure I better do some research into these power units.

Chocky.

Steve Lewin

If you're talking about the names of the motors e.g. Hacker B20-15, AX2820/10 then the meaning of the numbers varies by manufacturer. They're usually something to do with the physical size and electrical characteristics but you'll need some actual examples to get more than that.

Steve

Chocky

Steve,
The numbering code in question doesn't have the feel of a standard product code. As a for instance Kontronik make the Fun400-23, Fun400-28 or Fun400-36. Waht does the second number (23, 28 or 36) refer to? Presumably the '400' code is the equivalent of a brushed 400 motor (come to think of it I'm not sure what the '400' bit means either.

Tippie

It appears that "400" is for the length of the motor= 400mm. Graupner also uses that for their motors i.e. speed 300 = 300mm in length - speed 400 = 400mm in length. I looked at specs for the Kontronik motors but couldn't get the light bulb to turn on in the brain. There is no standard for motors used in the hobby thus the numbers only mean something to the manufacturer.

Steve Lewin

Like I said part is physical size, that Kontronik motor is equivalent in size to a Speed 400 (400s are actually around 40mm long not nearly 16 inches !). The last part for Kontronik is not the number of turns of wire in the motor, which is more common, it's the Kv (revs/Volt) divided by 100. The higher the number the "hotter" the motor, i.e. the more revs it produces for a given voltage.

(Edited cus I got it the wrong way round first time)

Steve

Chocky

Gents, Many thanks. I thought 400mm was erring on the large side for most of my airframes. I should be able to shoe horn in 40mm! Off to Sandown Park next weekend - I can feel a parting of the cash already.

Chocky

Tippie

Just shows you what I know about metric measurement. I just took the info from the Kontronik spec on the 'Overlander' web site. It says 400mm and I didn't question it. Other sites I checked since say 40mm. Sorry about the confusion.

Steve Lewin

BTW I just realised I was lying about the Kontronik numbering scheme, getting it confused with Hacker so I've edited the original message.

For Kontronik the 2nd number is not the number of turns it's related to the motor constant Kv (rpms/Volt) so it works the opposite way round to what I originally said. Higher number = hotter motor. Sorry .

Don't you wish they'd all get together and do it the same way ?

Steve

Chocky

If confusion and doubt can be sread it will be spread! A fellow flyer had a 'VIP' plane up the field on Tuesday night (very windy). Agreat little plane. Wingspan of about 300mm (not 30mm!) with a std Speed 400 up front on 7.2V 800maH pack. Clocked it at 75mph. Pretty impressive and also a bit tricky to see. Still off to the Sandown Display on Saturday with a wedge of cash. Thanks again to you all for the continued advice.
Chocky.