Scorpion

[inner3]

I see a lot of people using the scorpion motor. Would this work with the stock esc? Not interested in throwing a ton of money into it, especially with my current build.

[xpantz]

HKII-2208-24 max 21amps - This one is ok I think

HKII-2213-14 max 35 amps - This one wants more power

Both are better than stock. But if you want a noticable increase in power then better to go with the 2213-14. You don't need to run it on a high end ESC... Just one with a few more amps than stock. Nice to get GOV HS though if you have more power.

or join the queue for the wicked...

[inner3]

Yeah I'm in the queue for the wicked too. How long will it be, 2013?

[ahahn]

Originally Posted by xpantz

HKII-2208-24 max 21amps - This one is ok I think

HKII-2213-14 max 35 amps - This one wants more power

Both are better than stock. But if you want a noticable increase in power then better to go with the 2213-14. You don't need to run it on a high end ESC... Just one with a few more amps than stock. Nice to get GOV HS though if you have more power.

or join the queue for the wicked...

Power ratings have nothing to do with the current you draw. That is more a function of the particular motor Kv (for the same sized motor, higher Kv will draw more current, everything else staying the same). It is also a big function of the load. To first order, the Kv of the stock motor is the balance point. Higher Kv and you will pull more, equal will be about the same, and lower will be less. I note this depends on pinion staying the same. A higher tooth pinion will draw more current than a lower toothed one. If you go up in Kv by 10% and drop a pinion tooth (roughly 10% drop in # of teeth), the current won't be too different.

All the rating tells you is how much current the motor can take without burning up.

[xpantz]

I more or less understand the kv/load/power use relationship... a bit fuzzier on how much power is required to get a motor to develop maximum watts.

I understand it will run ok on less power... for the most part current draw is well under 25 amps... (smaller pinion it uses less... larger increases load and uses more) but I've seen this motor draw more than 35 amps (briefly)... and I'm not finished with it yet. :-)

I have no idea really if the stock ESC is happy providing all the power this motor can use if it's load is increased.

Would it be correct if I said that to make this motor work at maximum capacity it would want more power than the stock ESC can happily supply. (even if that is not necessary to get decent performance... as you probably would with 25 amps on this helicopter)

[dr_boom]

So how do you know how many amps the motor will pull then in certain situations?

Say you run a 12T pinion on the HKII-2208-24 (max 21amps). Running a 3S pack, will the motor ever pull more than the 21 amps from a 25 amp ESC?

[GSPI]

It's a possibility....depends on your altitude, head speeds and so on. I think Castle actually has a calculator which can give you a ballpark value.

[GSPI]

Sorry, here it is:

http://www.ecalc.ch/helicalc_e.htm?castle

it's a bit complex but gives you some insight as to how it might react.

[dr_boom]

Thanks for the link...this is frustrating. I'm showing you would need a 14T pinion with the Scorpion HKII-2208-24 to avoid the "unable to hover" warning. I think a fair weight with battery would be 610g for this heli. Plus, the motor chart makes it look like the motor case will have a temp overlimit below the case temp line.

I must be doing something wrong here, a Scorpion rep suggested this motor for the 300X.

[GSPI]

Actual weight of the 300X is 491g with battery so that will make some difference in your calculation. I had a bit of frustration myself with the program to try and get it to work. I'm note sure how they figure the unable to hover limits.