One of the most interesting and challenging parts of the conversion is power selection. Probably not for the glider, but for the trainer, well, it can be. The easist part of that is already done for you, it's a trainer, so you won't be going with a high torque high power (meaning high wattage) power system. The power system is the battery, the ESC, and the motor.

You will have to choose if you want brushed or brushless power. There are some web sites, and I believe Wattflyer is one, that has conversion info that can help you with the power to weight or watts per pound ratio. This is important, and, as I said, challenging because you have to consider the entire weight of the plane, which includes the motor with prop, esc, battery pack, receiver, servos, and fuselage.

Here are some guidelines:

1. Power can be measured in watts. For example: 1 horsepower = 746 watts

2. You determine watts by multiplying ‘volts’ times ‘amps’. Example: 10 volts x 10 amps = 100 watts

Volts x Amps = Watts

3. You can determine the power requirements of a model based on the ‘Input Watts Per Pound’ guidelines found below, using the flying weight of the model (with battery):

50-70 watts per pound; Minimum level of power for decent performance, good for lightly loaded slow flyer and park flyer models
70-90 watts per pound; Trainer and slow flying scale models
90-110 watts per pound; Sport aerobatic and fast flying scale models
110-130 watts per pound; Advanced aerobatic and high-speed models
130-150 watts per pound; Lightly loaded 3D models and ducted fans
150-200+ watts per pound; Unlimited performance 3D and aerobatic models

4. Determine the Input Watts Per Pound required to achieve the desired level of performance:

Example:

Model: E-flite Brio 10 ARF
Estimated Flying Weight w/Battery: 2.1 lbs
Desired Level of Performance: 150-200+ watts per pound; Unlimited performance 3D and aerobatics
2.1 lbs x 150 watts per pound = 315 Input Watts of total power (minimum) required to achieve the desired performance

5. Determine a suitable motor based on the model’s power requirements. In this case, you will need a motor/esc/battery combination for 30 amps continuous... 3 cell LiPo at 11.1 volts (nominal) is 315/11.1=28.xxx amps, round out to the higher 30 amps.

So, get your paper and pencil out and work out the details. Let us know if we can help.

CGr.