At school, every form in the year has to have at least one group submit into ascience fair type thing. My groups is attempting a remote controlled hellicopter. We've got the specifics of weight, speed and steering in design, but we can't figure out how remote controlled cars regulate power. Basically, how they make the wheels spin faster.

Any help is appreciated.

http://www.math.niu.edu/~behr/RC/speed-ctl.html

may help. or put 'RC speed control' into google and see what comes up.

The RC cars probably use pulse width modulation communicate the speed, and then power switching transistors are used to vary the speed of the motor using varied duty cycles. In the F.I.R.S.T. Robotics competition, the Victor speed controllers worked this way; however, they are probably a bit big for a remote control 'copter. I can get more technical if you are interested.

I thought that remote controlled cars work by increasing the amount of electricity supplied by a battery. I'm really not sure what you're talking about, but I definately want to know more.

Thanks

They do; but the details are odd. Instead of using a transistor and varying the power with it directly (which would burn up power), pulse width modulation (PWM) is used.

For example, take a period like 1/1000 of a second and turn the power on for half of it. Repeat this 1000 times consecutively and you have the motor operating at roughly half of the voltage for one second. Turn it on for three-fourths of the time and it goes faster; one-quarter of the time is slower. The motor "feels" the root mean square (RMS; kinda like the average; exact calculation involves calculus, though I don't know the details) of the voltage you're putting into it. The power made available to the motor from the battery is varied, but this way is used to save power.

The percent of the cycle that the power is on is called the "duty cycle."
The amount of time you turn it on divided by the amount of time per cycle is the "duty cycle."

The Victor 883 (http://www.ifirobotics.com/victor-883-speed-controller-robots.htm) uses this method, though it may be a bit pricey for your application.

RC communcation PWM functions somewhat differently because of its purpose.