KingMax BLS7731HHV Brushless HV Waterproof Servo – 28.42kg Steel Gear Digital Servo
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KingMax BLS7731HHV Brushless HV Waterproof Digital Servo
The KingMax BLS7731HHV is a high-performance programmable digital high-voltage servo designed for demanding RC aircraft and helicopter applications requiring exceptional torque, durability, and precise control.
Featuring a high-quality brushless motor, high-precision Taiwan-made steel gears, dual ball bearings, waterproof construction, and a full CNC aluminum case, the BLS7731HHV delivers up to 28.42kg-cm (394.75 oz-in) of torque at 8.4V while maintaining fast response times as low as 0.09 sec/60°.
Designed for high-load applications, the BLS7731HHV is an excellent choice for giant scale sport aircraft, large warbirds, aerobatic airplanes, sport jets, and demanding control surface installations. It is also suitable for 600–800 class helicopter swashplate applications.
Features
- High-performance programmable digital HV servo
- High-precision Taiwan-made steel gears
- High-quality brushless motor
- Full CNC aluminum hull and structure
- Dual ball bearings (2BB)
- Waterproof construction
- Standard 25T spline
- Ideal for high-load aircraft control surfaces
- Suitable for 600–800 class helicopter swashplate applications
Servo Arm Compatibility
The BLS7731HHV uses a standard 25-tooth output spline that is compatible with Futaba-style 25T servo arms and accessories. This allows the servo to work with most aftermarket aluminum, carbon fiber, and composite servo arms designed for the popular 25T standard.
Speed & Torque
| Voltage | Speed | Torque |
|---|---|---|
| 6.0V | 0.11 sec/60° | 22.05kg-cm (306.27 oz-in) |
| 7.4V | 0.10 sec/60° | 26.50kg-cm (368.08 oz-in) |
| 8.4V | 0.09 sec/60° | 28.42kg-cm (394.75 oz-in) |
Specifications
| Model | BLS7731HHV |
| Servo Type | Programmable Digital High Voltage Servo |
| Gear Train | High-Precision Taiwan-Made Steel Gears |
| Motor | Brushless Motor |
| Case Construction | Full CNC Aluminum Hull and Structure |
| Bearings | Dual Ball Bearings (2BB) |
| Spline | Standard 25T |
| Dead Band | 2μs Default |
| Waterproof | Yes |
| Operating Voltage | DC 6.0V–8.4V |
| Rated Working Voltage | DC 7.4V |
| Working Frequency | 1520μs / 330Hz |
| Working Angle | ±63° @ 800μs–2200μs |
| Dimensions | 40 × 20 × 39.5mm (1.57 × 0.79 × 1.56 in) |
| Weight | 77.5g (2.45 oz) |
| Connector | JR Connector |
| Wire Length | 320mm (12.6 in) |
| Working Temperature | -10°C to +50°C (14°F to 122°F) |
| Storage Temperature | -20°C to +60°C (-4°F to 140°F) |
Recommended Applications
- 35cc–60cc gas-powered RC aircraft
- Giant scale sport airplanes
- Aerobatic and IMAC aircraft
- Large warbirds
- Sport jets and turbine aircraft
- High-load elevator, rudder, and aileron installations
- Scale aircraft requiring high torque and precise centering
- 600–800 class helicopter swashplate applications
Why Choose the BLS7731HHV?
- Up to 394.75 oz-in of torque at 8.4V
- Brushless motor for efficiency and long service life
- Taiwan-made steel gears for durability under heavy loads
- Waterproof construction for demanding field conditions
- Full CNC aluminum construction for strength and heat dissipation
- Fast response with excellent holding power and centering
- Compatible with Futaba-style 25T servo arms and accessories
Includes
- KingMax BLS7731HHV Brushless HV Waterproof Servo
- Manufacturer-supplied servo accessories