RPM and rollout question/decision help?

[VintageMA]

Originally Posted by nuz69

Neu 1512 1.5 : 10.23 oz
Castle/neu 1512 1Y : 13.1 oz

Hmmm... fair enough - should have looked up the specs instead of making an assumption.

Originally Posted by nuz69

It appears that the Castle/neu has a little less efficiency than the real american neu.

Previous research and threads from Patrick have shown that the Castle Neu's will run about 10* hotter than the hand-built Neu's, IIRC.

Originally Posted by nuz69

The electromagnetic efficiency depends a lot of the load, not of the RPM : between 25k and 40k efficiency is the same. But mechnical losses are higher at 40k.
==> For the same top speed and same voltage, the 1850kV will always provide better results for in matter of temps and runtimes...
==> I would keep the neu.

What is your source of this information?
In my own personal experience, many years of testing and many $$$ spent on about 15-20 different Neu motors has shown me that 35-40K is the sweetest spot for these motors. Heli guys run them up in the 50k rpm range - which I have found in surface gets them hot way fast.

The truth of the matter is that 4S is not the sweet spot for heat and efficiency - 6S and higher is. More voltage = less current for the same power and that equals less heat. But if 4S is a requirement - go with the 2650 motor. Going with the 1850 and trying to gear for 40mph is going to create a lot of heat.

Just my opinion -

Originally Posted by nuz69

Who is jeff ? ^^

jhautz