Electric Flight Specialist since

Electric Flight Specialist since 1999

H ow to pick a motor and battery for your model.....a simple guide.

· Estimate the model weight ready to fly (airframe + approx 40% for motor and battery pack, see motor battery and speed controller pages for weights.

· Select the amount of power (Watts/Pound) required for the type of model (50-60+ for Glider, 60-80+ for Sport, 80-110+ Aerobatic, 120+ Ducted fan).

· Select a motor from our motors pages which will deliver the required amount of power and confirm the

actual AUW is similar to your original estimated weight.

· Confirm the battery pack will provide the amps and voltage to produce the required power.

Amps x Volts = Watts (use 80% of battery max amp rating for calculations) and that it will physicaly fit into the model! Larger capacity (mAh) will give longer duration at a weight penalty.

· Confirm the motor will produce the required power for the anticipated flying speed / model characteristics when using a prop from the recommended size range / prop data. Revise original motor / battery selection if required, to obtain your requirements.

Example: - Sport model (80w/lb) weighing 2lb, allow 3/4lb (40% of model weight) for motor and Li-Po pack (in this example: - initially select 250w motor and 3S 2200 mAh Li-Po battery)

Power required: - 2 ¾ x 80 = 220 watts (220watts divided by 10volts (nominal 3S pack voltage under load = 22Amps therefore you will need a speed controller that will handle 22A @ 80% of its rating)

Confirm the motor can be propped to draw 22 Amps when running on 10 Volts. Confirm the battery is capable of supplying 22A (2200 mAh 20c pack can safely deliver 36A (80% of its continuous rating) and the selected speed controller (30A in this example) will be operating within its limits. (80% of continuous rating)

This example: - 250w motor /2200 mAh 20c 3S Li-po battery and 30A ESC OK! Package price £49.99