brushless conversion

Revo mix takes a percentage of the pitch output and feeds it into the rudder output.

In control system terms, this is a feed forward input which increases the anti-torque force of the tail rotor as the torque from the main rotor increases as you pull more pitch on the blades.

A motor's top speed (RPM) is determined by several things but one that is useful to be able to discover is the number of poles. Normally we don't need to worry about this as the KV value gives a pretty good idea of what the motor will do in terms of revolutions per minute per volt (RPM/V). Sometimes however it's useful to know.. like when setting up governed head speeds in BLHelisuite which I use on the BL mCPX.

Substituting a modern brushless motor for the original brushed one should be fairly straight forward. Depending on your exact model you may not even have to change your 4-in-1.

There's a great hack for the E-Sky HoneyBee which just requires opening the 4-in-1 and tapping the main throttle output from the receiver before it goes into the speed controller. Here's one link showing the procedure: E Sky 4-in-1 brushless mod