WHAT IS THE BEST PINION FOR MY ELECTRIC HELICOPTER

To prevent your ESC from generating excessive heat, it is recommended to run throttle over 80% continues and target speed at approximately 90% to give you 10% of variation.

To select a suitable pinion gear you need to have the following information handy:



HS - Target Headspeed
KV - Motor KV value - rpm per volt
MG - Main gear teeth count
C - number of cells to run

Let's start......

headspeed = C x 3.7 x KV x pinion gear / MG

Thus, to run the ESC at 90% throttle, formula becomes

target headspeed = 3.7 C x KV x pinion gear / MG x 90%

To calculate the pinion gear converse the formula to the following

pinion gear = (HS x MG) / (KV x 3.7C x 0.9)



For example, a stock Trex 450 has follow figure on a 3 S Lipo:

MG = 150
KV = 3,700
C = 3

and target headspeed is 3,000 rpm

pinion gear = (3,000 x 150) / ( 3,700 x 3.7 x 3 x 0.9) = 12.17 T

So closest pinion giving 3,000 headspeed is 12T at 91.3% throttle