Brushless Motors for the HK450

I recommend the Turnigy 2836 450 Size Heli Motor

Why?
Well firstly we need a motor that can deliver anywhere from 3200kv to 4000kv
KV means revolutions per minute per volt
so if the supply is 1volt then the motor spins at the KV rating, then at 2 volts twice the rating all the way up to 11.1v the motor will be “theoretically spinning at 44,400 rpm, but this never happens in practice because of load / losses.
The head speed required by a 450 class motor is 2800 rpm to 3000 rpm at 0 pitch and maximum throttle, 2800 usually for plastic heads and or wooden blades, and 3000 rpm for metal head with fiberglass or carbon fiber blades, some people push it up to 3200 rpm with metal head and carbon fiber blades.
Simply the motor I use is because it has the ability to supply all the power you could ever require from a HK450 heli even at 11 deg pitch plus and minus although standard pitch is 9 degrees.
To do the math’s
A 450 Heli hovering is at 15Amps and does punch outs at up to 40Amps
So working out the wattage this is what we get
P=EI which means P is Watts, E is Voltage, and I is Amps.
So P = 11.1v x 40Amps = around 450 Watts
Now remembering the following that as the current / Amps increase so to do the losses a motor experiences, so if you use a 500w motor that’s is 80% efficient then this is already at 400watts at its maximum efficiency, after this point it has greater losses, and in some cases cannot reach this level of 450watts, but as a bare minimum the motor will draw more amps and get very hot.
So why the 700 watts motor, well let’s take the efficiency of 80% as no motor is 100% efficient and now look at the amount it can comfortable deliver and that is 560watts continuous. What this achieves for us is a motor that runs cool; actually it will never get past touch warm.
So this is not the only reason behind choosing such a motor, the simple fact is that it is only 10 - 12 grams heavier than lower wattage motors and therefore worth it. It’s simply bought once and never worry about it again.
 
Regards
Elias Gourvelos (EatAtJoes)