BrotherHobby Avenger 2306.5 V3 2000KV

The BrotherHobby Avenger 2306.5 V3 2000KV is a brushless outrunner for 5-inch FPV quadcopters, the small, fast freestyle and racing class. BrotherHobby is a Chinese maker of FPV drive components. The motor has 12 slots and 14 magnet poles (12N14P), N52H arc magnets, NMB bearings and a hollow titanium shaft.

The KV rating of 2,000 is the no-load speed per volt; on 6S at 22.2 V nominal that works out at roughly 44,400 rpm unloaded, and under a 5-inch propeller the speed settles well below that. The stator code 2306.5 stands for 23 mm diameter and 6.5 mm height; half a millimetre more stack height than the common 2306 means a little more iron and copper in the magnetic field, and so more torque. The motor weighs 33.6 g including a 16 cm lead. The permitted cell count is 5 to 6S.

Motor, speed controller (ESC) and battery must all tolerate the same cell count, here 5 to 6S, and a propeller that is clearly too large overloads motor and controller. Which rules apply to a flight depends on the whole aircraft, not on the motor: the EU classes C0 to C6 follow the take-off mass, and operator registration is due from 250 g or with a camera that can capture personal data. A 5-inch quadcopter on 6S normally exceeds the 250 g of class C0 once it is ready to fly.

On a crash-prone machine like this, shaft, bearings and cables wear first. A hollow titanium shaft tends to bend in hard impacts rather than break, and a wobble at the propeller seat reveals it. NMB bearings suffer from sand, grass and moisture; a bell that runs rough, scrapes or has play needs new bearings. The winding suffers from sustained heat – discoloured varnish and a burnt smell point to damaged insulation. Also worth checking are whether the arc magnets sit firmly in the bell and whether the cables chafe where they leave the motor.