Scorpion HK-4540-400kv (8mm) ULTIMATE

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Scorpion HK-4540-400kv (8mm) ULTIMATE

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Scorpion Competition Series Brushless Motors are built from the best materials available, and are designed to provide both quality and performance at an affordable price. Scorpion starts with high quality aluminum alloy parts that are produced on the latest CNC milling machines. These parts are then gold electro-coated to provide a beautiful, long-lasting finish. The stators are made with 0.2mm laminations to give maximum efficiency, and minimum Eddy current losses. The stators are epoxy coated to prevent shorts, and are wound with wire that is rated at 180 degrees C (356 F). The magnets used in Scorpion Motors are custom manufactured to be able to withstand high temperatures, making a motor that is virtually impossible to burn up in normal use.

Scorpion Motors are built to last, and are backed with a 2-Year warranty against defects in materials or workmanship. However, due to the high RPM of these motors, and the fact that we cannot control the installation and setup, the bearings are not covered by the 2-Year warranty, nor is any subsequent damage caused to the motor by a bearing failure. Bearings are a normal wear item, and as such, need to be maintained and changed periodically. For maximum life, make sure that a sufficient gap is left between the pinion and main gear during motor installation to avoid binding, and put a small drop of oil on each bearing every 5-6 flights. It is the responsibility of the pilot to ensure that the bearings are maintained properly.

For the best overall combination of quality, performance, and value, use Scorpion Motors in your helicopter!


Scorpion HK-4540-400kv (8mm) ULTIMATE Specifications
Stator Diameter45.0 mm (1.77 in)
Stator Thickness40 mm (1.57 in)
Number of Stator Arms12
Number of Magnet Poles10
Motor Wind5T+5T double Wye (YY)
Motor Wire1-Strand 1.5mm
Motor Kv Value400 RPM per Volt
No Load Current (Io)1.65 Amps @ 10 Volts
Motor Resistance (Rm) per Phase0.013 Ohms
Maximum Continuous Current150 Amps
Maximum Continuous Power (18S)10,000 Watts
Peak Current (3 Seconds)200 Amps
Peak Power (3 Seconds)15,000 Watts
Motor Weight719 grams (25.35 oz.)
Outside Diameter56.7 mm (2.23 in.)
Shaft Diameter7.98 mm (0.37 in.)
Motor Body Length71.9 mm (2.83 in.)
Overall Shaft Length127.3 mm (5.01 in.)
Max LiPo Cell12s-18s
Motor Timing18deg to 24deg
Drive Frequency8kHz

Weight including packaging


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