Reply To: Engines

Model electric flight is causing some wonderful outrunner brushless motors to be manufactured such as this rather nice 20kW one! see:- http://www.rcgroups.com/forums/showthread.php?t=571975

I understand it weighs only 3kg 😎

I am currently doing some sums to see what 'off the peg' e-flight motors and controllers would do in this application. One of the big advantages is that e-flight systems are designed to run typically from 10 cell LiPo packs (i.e. 38v) so would run quite conservatively from 28v. Keeping below 50v has the advantage of avoiding all the 'fun' of the EU 'high voltage' directive which I believe applies to nominal 48v systems as they exceed the magic 50v when on charge.

As a quick sum I have looked at what could be achieved with 4 off EFLM4160A motors clustered around a 5.3:1 gearbox. These motors are continuously rated at 60amps and with about 90% efficiency would give almost exactly 6kW output. The motors would turn at 6860 rpm on 28v so the 5.3:1 box would drop this to 1295rpm almost exactly matching the continuously rated output and speed of a Yanmar 1GM10 with a 2.64:1 gearbox. The best price I can find on these motors is 163 US dollars each. Brushless controllers run out about the same price so the total for 4 motors and controllers would be about 1300 US dollars. Brushless motors can be reversed by the controller so there is no need for a gear reverse and no heavy switchgear.