Shanghai Dualsky Models Co., Ltd. XM5060EA-20SE V3 250KV

The Dualsky XM5060EA-20SE V3 250KV is an outrunner from the EA V3 series in the longer format, designed as a 12S high-voltage motor for unmanned aircraft (UAV) in the mid-size multicopter class. Dualsky is based in Shanghai. The case measures 49.5 mm in diameter and 58.2 mm in height; the longer stator stack gives more torque at the same diameter.

The motor weighs 395 g and reaches up to 2,664 W at up to 60 A; here too the sum works, since 60 A at 44.4 V, the nominal voltage of 12S, gives exactly 2,664 W. That is about 6.7 W per gram of motor mass, though as a peak value. At 250 KV the motor turns roughly 11,100 rpm unloaded on 12S; the recommended propellers are 15x10E, 16x8E and 16x10E for 12S. Permitted cell counts are 10 to 12S.

From data sheet to design: motor, speed controller (ESC) and battery must carry the same cell count, and a peak current of 60 A calls for a controller with clear headroom. The dimensions of 49.5 x 58.2 mm decide, together with the hole pattern, whether the motor fits the arm. The power figures hold for a time span that lies between 3 and 180 s depending on the maker; for continuous hovering only a fraction of them counts. Four of these motors weigh 1,580 g on their own; with frame, battery and payload such a quadcopter sits above the 900 g of C1 and, depending on equipment, above the 4 kg of C2 as well.

When buying second-hand and in service, bearings and rotor bell are the first checks: 16-inch propellers create imbalance and bending loads, and after a hard landing the bell can distort and rub on the stator. The winding tolerates peak currents but ages under lasting heat; brownish varnish or a smell of overheating are warning signs. In high-voltage operation the battery connector should have spark protection.