lightweight, inexpensive speed controllers

[efoote868]

Originally Posted by Redo91

I'm going to add that brushless motors are a must. The way a brushless motor operates makes their speed much more controllable than a brushed DC motor.
There are also ESCs with a BEC built in that provide power to your flight controller.

If I were to approach this problem, I might start by looking at what's available to the average consumer / near hobbyist level. I believe brushed DC motors are used on the popular Syma S107G model and knockoffs, and searching Ebay I can get a pair of them from China for $6 (including shipping).

One could also try to cannibalize more of that helicopter to get appropriate (and proven) gear ratios, as well as mounting hardware.

Controlling a brushless DC motor is not trivial, which is to say that as a hobbyist you wouldn't build one from scratch as you might an H-bridge or other brushed DC motor controller.