Single vs Twin motor for an electric RC airplane I'm designing a fixed wing UAV for a project. I need an airplane that can fly for at least 200 minutes. Obviously, it means a big battery and thus a lot of added weight. I've been debating whether or not I need a twin motor configuration. The idea came after I saw a video of a modified &quot;My twin dream&quot; airplane that has a range of 269 km and can fly for more than 5 hours. The extra thrust might be the reason it can fly for that long but I can not find any research for electric twin motors whatsoever.
Let's say the cruise speed would be 15 m/s. If it only has one motor, maybe it would need to run at 90% of its power vs if it has two motors they would need to be at 45% of their power to match the required thrust for that cruise speed. This could mean, two motors are more efficient than one, even though the extra weight of the added motor.
I'm not sure how to solve this problem.
You should keep in mind that adding an engine adds wiring, extra propeller (a larger single prop might to be lighter in RC than an equal setup of two), overall complexity etc.
As I understand it, electric motors have a &quot;sweet spot&quot;, or rather an area of (iirc) certain load and rpm. You should desing your configuration so, that the motor(s) would operate in this rpm/load range in cruise. This sweet spot is (again, iirc) much higher than half load. So it is likely you are better of with a single engine than two that are only utilizing about half their rated pwr.
This sweet spot is very motor specific, so you need to dig deep into spec sheets.