Electric Twins
Six Steps to Success
With today’s ultra-reliable electric power systems, e-twins are extremely popular. As with all types of airplanes, reliability is key and electric twins have this in spades! Here are some basic rules to keep your electric-powered twin happy.
1. Use one controller for each motor.
2. When using one battery pack for all motors, be sure its capacity exceeds the requirements of the combined current of both motors. (If each motor draws 25 amps and there are two motors, the pack must be able to handle 50 amps).
3. Use only one BEC unless the manufacturer says it’s okay to wire two in parallel at the receiver.
4. Use a Y-harness for all receiver connections from the speed control to your throttle input on the receiver.
5. Keep all wires as short as possible from the battery to the speed control and from the speed control to the motors.
6. Never use “auto-calibrate” on throttle settings for multi-motor aircraft.
THROTTLE NOTES
Choosing the wrong throttle settings with a programmable speed control can cause erratic motor behavior in multi-motor setups. Most controllers have a programming section that default to “auto-calibrate” or “auto-throttle,” and those work fi ne for single motor setups. When setting up your twin, be sure to change that to “fixed endpoints” or “manual calibration” depending on your speed control’s manufacturer.
This involves powering up the power systems with the throttle at its low (or highest, depending on instructions) position and then moving it through its full range of movement. A tone at each throttle limit usually signals it is okay to move to the other limit and the speed control has set the positions of the radio’s throttle stick to match the motors. The throttles are now synced.