Hobbywing XeRun AXE 4987 R3S: the FOC brushless motor for 1/5 and 1/6 crawlers

Photo: Hobbywing (source)

The Hobbywing XeRun AXE 4987 R3S pushes the AXE family towards the top of the catalogue: this sensored brushless motor with FOC control targets large-scale crawlers, in 1/5 as well as 1/6, where torque and throttle finesse matter infinitely more than top speed.

Hobbywing XeRun AXE 4987 R3S: the spec sheet

• Type: sensored brushless, FOC control, 4 poles
• Rating: 1600 KV
• Dimensions: 49.5 mm diameter, 87 mm can length
• Output shaft: 5 mm
• Weight: 660 g
• Power: 3S to 8S LiPo
• No-load current: 12.1 A
• Wiring: three 10 AWG leads, 300 mm, 6.5 mm male connectors
• Part number: 30401402

A magnetic encoder instead of Hall sensors

The real news lies in how rotor position is measured. Where a conventional motor makes do with Hall-effect sensors, the 4987 R3S carries a magnetic encoder that Hobbywing claims is sixty times more accurate. In practice, that is what allows FOC control to deliver clean torque from the very first degrees of trigger travel, with no jolt and no dead spot, exactly what a crawling motor is asked for when a wheel has to be placed on a ledge to the millimetre.

Shorter than the competition, and stronger

With its 87 mm can, the motor claims 3 mm less than a 4990 while producing roughly 8 % more power. On a 1/6 chassis, those few millimetres are often squeezed in with a shoehorn between the transmission and the cell: the gain is not trivial. The rest of the build follows the same robustness logic, with a CNC-machined aluminium can, quality bearings and enamelled wire rated to 200 °C.

IP66 rating and compatibility

The XeRun AXE 4987 R3S is IP66 certified, which clears it without argument for rain, snow, mud, sand or water crossings. It is designed to run with the XeRun AXE Plus R3 speed controller, provided you have at least firmware 1.1.3. On the vehicle side, Hobbywing lists the 1/6 CrossRC EMO XX and EMO XX2 as well as the Axial SCX6.