Brushless spinner

[Andrew_Hibberd]

I have been dreaming about a spinner for a long time and would like more information about how much lipos can actually give?

I am thinking of using a 2 cell 340Mah lipo and a pheonix 10 controller

I would like to now if it would be possible to use a
300DF brushless motor:

Current 6.8 to 8.1 Amps continuous
KV 2250 rpm per Volt
Prop (direct drive) 5? x 3? or 6? x 3?
Output 21,000 rpm with 5? x 3? or 13,560 with 6? x 3?
Thrust 400g and 320g respectively.
Body Diameter 25.6mm.
Body Length 17.7mm.
Weight 26g
Shaft 2.3mm
SMC-M-APMBL300

Even though the batteries say they can only give 6.8A would this be possible to use this combination?

The other option is to use a
AXI 2204/54

Suitable for models weighing 100-280g
No of cells 6-7, 2 x Li-Poly - RPM/Volt 1380 - Current Capacity 6.5A/30s - Dimensions 27.5 x 23mm - Shaft Di. 3.17mm - Weight 24.5g
Jeti Brushless speed controller to suit
SMC-RE-JESBA08-3P


however another web site said the ouput is wobbly to save props in case of a crash. SO this might not be great.

Does anyone know any good brushless motors that i can use this lipo with that weighs less than 30g?

Thanks in advance
Andrew





All this data was from http://www.sussex-model-centre.co.uk

[BeligerAnt]

I'm always slightly bemused by model motor "specs"...

I can only assume that the 6.8 to 8.1A is with the quoted prop, generating the quoted thrust. A spinner weapon is likely to require much less current most of the time (unless you're trying to use the disc for propulsion! ) as it has much less wind resistance, and therefore represents a much smaller load on the motor.
Expect the motor to take as much current as it can while the disc speeds up (probably limited by the speed controller).
The battery current limit is due to the internal resistance of the cells. This resistance dissipates power in the form of heat, which if not limited would eventually result in the destruction of the cells (bad!). However, a short duration overload at a limited current should be OK as the heat will not build up too much. A dead short circuit would be very bad news very quickly though!

[Cavecrusher]

try a AXI 2204/54, said by a satisfied customer.

the Kokam 360 HD can deliver by the specs i have been given when i've bought them, 7 amps at 90% capacity and 9 amps at 70 % capacity.

[Remote-Controlled Dave]

I have sooooo much to learn......

[Andrew_Hibberd]

I have a disc which has 6 teeth, would it be better to use the slower AXI or the quicker 300DF motor? Or is that just personal choice?

[BeligerAnt]

Andrew, since spinning weapons are basically energy storage devices, and the energy is stored as kinetic energy, you want the disc to go as fast as possible!
However, that's not quite the whole story as you need to take into account acceleration time, power consumption (how long your batteries will last!), weight, etc etc
You may well also find that the slower motor is "more than enough". This would imply though that the bigger motor would be overkill - hang on, overkill in combat robotics? - No such thing! Fit the biggest motor you can!

Dave: Don't we all...

[peterwaller]

I use the 300DF motor with three cell 340 lipo on all of my spinners. If anything they suffer from too much power sometimes so two cells might be a better option.

[Andrew_Hibberd]

This is quite interesting. I will definatly be using a two cell pack, but it is the anticyclone motor or the DBA one 8) , i know DBA uses a 2cell battery with some effect . I have some time beffore i can build this ant so i will see if either of them comes up on ebay

EDIT, are there anyother brushless motors that weight under 30g?

[Andrew_Hibberd]

How is the best way to mount a brushless motor? How do you wire it, how do you attach a disc and what do the little screw do on the end of the motor?

http://www.aurorra.co.uk/cgi-bin/trolle ... ETMICRO33D

[Andrew_Hibberd]

I have bouught one of those motors now with plans to build a walker. Watch this space