Scorpion HKII-4525-520 Ultimate Brushless Motor, Kv=520

Write A Review

Scorpion HKII-4525-520 Ultimate Brushless Motor, Kv=520

In Stock


In September of 2010, Scorpion released the first HK-4525-520kv Limited Edition motor. Since that date, the HK-4525 has been the motor of choice for 700-class RC helicopters, and has become the performance benchmark for every other model motor manufacturer. Eighteen months later, in April of 2012, we released an improved version of this motor, the HK-4525-520kv Ultimate Edition. Since then, the Ultimate Edition motor has proven itself to be extremely successful in heli competitions, and has become the most popular motor used in competition 700-class helicopters world-wide.

Many other motor manufacturers have tried to compete with this motor, but none have been successful. We even tried for years to improve the HK-4525-520 motor but were unable to do so. Finally, after nearly 5 years of testing and development, we are pleased to announce the release of the new next generation HKII-4525-520kv Ultimate motor.

Each of the new HK-4525-520KV ULTIMATE motors are wound with a single strand of 1.4mm wire for the highest possible efficiency. This motor is capable of running continuously at an input power of 4450 watts at 100 amps, and can handle peak inputs of 10200 watts and 230 amps for two seconds

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 lamination's 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.

*This motor is using 30mm bolt spacing on the mounting with M4 screw holes


Scorpion HK-4525-520 Ultimate Motor Specifications
 Stator Diameter45 mm (1.77 in)
 Stator Thickness 25 mm (0.98 in)
 Number of Stator Slots 12
 Number of Magnet Poles 10
 Motor Wind 5+6 Turn YY
 Motor Wire 1-Strand 1.4mm
 Motor Kv Value 520 RPM per Volt
 No Load Current (Io) 1.81 Amps @ 10 Volts
 Motor Resistance (Rm) per Phase 0.012 Ohms
 Maximum Continuous Current 100 Amps
 Max Continuous Power (12-cell Li-Po) 4450 Watts
 Motor Weight 516 grams (18.20 oz.)
 Outside Diameter 56.9 mm (2.24 in.)
 Shaft Diameter 5.98 mm (0.24 in.)
 Motor Body Length 57.7 mm (2.27 in.)
 Overall Shaft Length 112 mm (4.41 in.)
 Max Li-Po Cell 12s
 Peak Current 230 Amps (2 seconds)
 Peak Continuous Power 10,200 Watts (2 seconds)
 Motor Timing 5 to 15 degrees
 Drive Frequency 8 KHz

Included in the box

1 x Scorpion HK-4525-520KV Motor
4 x M4 x 8mm Mounting Screws
3 x Scorpion 6mm XL Female Bullet Connectors
3 x Heat Shrink for Bullet Connectors

Weight including packaging


View Scorpion HKII-4525-520KV - ULTIMATE Full Dimension
Scorpion HKII-4525-520 ULTIMATE

Write A Review

Only registered users can write reviews. Please log in or register

Customer Reviews

This product has not been reviewed. You could write the first review.