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Building The U. Maine Trainer

- Motor and Avionics -

(last update: 11 Dec 2012)


This plane is designed to fly with a power source.

The power source chosen is an electric motor. A good technology for such an electric motor is an extension from the ubiquitous stepper motor, called a brush-less DC motor. Motors of this type, used to power small aircraft, where initially adapted computer hard drive motors.

Modern dedicated aircraft brush-less DC motors are powerful. However, they do require a more sophisticated controller than traditional brushed DC motors. These controllers allow the pilot to set their power output. Indeed the motor would not run at all if it were not for the controller. Unlike a traditional brushed DC motor, they will not run if all you do is connect them to a battery. Fortunately the present state of the brush-less DC motor technology makes using them easy, and cost effective.

Our chosen power source is as follows:

As the above list suggests, there is a motor, a propeller, a motor controller, sometimes referred to as an ESC (Electronic Speed Control), a receiver, and a battery.

Note that the receiver above operates in the 72 MHz RC band. Many modern RC transmitters and receivers operate in the microwave bands, often the S band (2 to 4 GHz), at or about 2.4 GHz.

The battery is the power source proper. The motor along with the propeller convert the battery's electric power into thrust. The ESC converts the control signals collected by the receiver, into electrical pulses which the motor can respond to, in a useful manner.