BLS835 HV Brushless Digital Servo 45.0Kgf.cm 0.13sec/60° for 550-700 Class Helicopters
KST BLS835 HV Brushless Digital Servo
The KST BLS835 is a high-performance, high-voltage brushless digital servo engineered for demanding 550–700 class helicopters. At 8.4V, it delivers an impressive 45.0kgf·cm of stall torque with a fast 0.13 sec/60° speed, providing the power and response needed for high-load helicopter applications.
Built for durability and precise control, the BLS835 features a rugged aluminum alloy housing for improved heat dissipation, a hardened steel geartrain, and dual ball bearings for smooth and reliable operation. Its programmable brushless DC motor provides additional flexibility for fine-tuning the servo to suit different setups.
The BLS835 also features soft-start functionality to help provide smoother and more controlled servo movement during startup. With a rated operating temperature range of -20°C to +65°C, it is designed to maintain reliable performance across demanding conditions.
Combining extreme torque, fast response, high-voltage capability, and programmable brushless performance, the BLS835 is a powerful choice for serious 550–700 class helicopter setups.

Features
- Ultra High Torque & Excellent Speed
- Hardened Steel Gear
- CNC Aluminium Case
- High Quality Brushless Motor
- Dual Ball Bearings
- Ideal for 550-700 Class Helicopters
Specification
| Parameter | Value |
| Rated Voltage | DC7.4V |
| Voltage Range | DC6.0V-8.4V |
| Stalling Torque | 30.0Kgf.cm@6.0V / 38.0Kgf.cm@7.4V / 45.0Kgf.cm@8.4V |
| No-load Speed | 0.16sec/60°@6.0V / 0.14sec/60°@7.4V / 0.13sec/60°@8.4V |
| Working Frequency | 1520us/333Hz |
| Default Travel Angle | ±50° = 100° Total |
| Temperature Range | -20℃ ~ +65℃ |
| Soft Start | Programmable |
| Programmable | Yes |
| Case Material | Aluminum Alloy |
| Motor Type | Brushless DC Motor |
| Gear Set Material | Hardened Steel |
| Position Sensor | Potentiometer |
| Ball Bearing | 2BB |
| Case Dimensions | 40.5 × 20 × 38mm ±0.2mm |
| Weight | 70g ±10% |
Package Includes
- 1 * BLS835 HV Servo
- 5 * Plastic Servo Horn
- 1 * Servo Horn Screw
- 4 * Eyelet
- 4 * Grommet
- 4 * Mounting Screw