It takes roughly about 450W for a FJ to go 100 MPH.

Watt = AMPs X Volts {Volts read with motor running, means under load}

With lower quality or very cheap motors, it is better to aim for a bit more power to ensure going over 100 MPH.

So lets aim a bit high as is in 550W, extra50W waste in hobby city motor and extra 50W to go a bit over 100 MPH.

550W can be done with various number of cells.

Assume 3.5V/cell under load

3S= 10.5V
4S= 14V

550W /10.5V = 52.4A
550W / 14V = 39.3A

Assuming that even cheaper ESC's will be good for 4S, you can see that 40A ESC will be cheaper than 55/60A ESC. (If you can afford it buy Turnigy Plush series….maybe get 60A anyway pending your budget)…..Actually work with Chipped prop on that, he knows which ones are better deal.

Pending the Charger that you have, or the number of cells that you want, you can decide on ESC, motor.

Note there will not be a big difference in battery size, weight or price as far as 3S vs 4S.
Why? 4S will need less AMPs, so cells will be smaller....3S will have 1/3 larger cells, 4S will have 1/3 more number of cells....works out to be same....same size, weight, price , power, and flight time if all else is equal and different KVs are matched up to different number of cells etc.....

For Higher voltage lower KV motor will be needed.
For Lower voltage, higher KV motor will be needed.

If you want to climb very well, I mean exceptionally then you don’t want a very small prop.


Post your setup for comment by folks and see what they think


The above “Does” have a lot of generalizations but gives you an idea.

If using 28mm inrunner motors, you would be better off with 480 size (110 gram) motors as opposed to 400 size (80 gram) motors...not accounting for heat sink weight.(add a few grams for HC motors)
The 480 motors will handle the AMPs better and have better efficiency and run cooler too (than 400 sized motors).


Gryphon