KST A20-3813 V8.0 Brushless HV Servo – 43kg.cm High-Torque Servo

The KST A20-3813 V8.0 Brushless HV Servo is a high-performance, high-torque digital servo designed for demanding large-scale RC aircraft, aerobatic models and 3D airplanes. With an impressive 43kg.cm of torque at 8.4V and a fast 0.12 sec/60° response, this servo delivers the power, precision and speed required for large control surfaces and high-performance flight.

At the heart of the A20-3813 is a high-efficiency brushless DC motor, combined with a heavy-duty phosphor bronze and hardened steel gear train. The rigid CNC-machined aluminum housing provides excellent strength and helps dissipate heat during demanding operation.

With its standard-size 20mm servo case, high-voltage capability and massive torque output, the A20-3813 V8.0 is an excellent choice for large aerobatic RC planes, 3D aircraft, giant-scale models and other applications where reliable high torque is essential.

Built for Large and High-Performance RC Aircraft

The KST A20-3813 V8.0 is designed for pilots who need substantially more power than a conventional standard-size servo can provide.

With up to 43kg.cm of torque, it is ideally suited for large control surfaces such as:

• Ailerons

• Elevators

• Rudders

• Flaps

• Throttle and other high-load applications

The powerful brushless motor provides fast and precise movement, while the heavy-duty gear train is engineered to handle the high loads generated by large RC aircraft.

Brushless Power and High-Voltage Performance

The brushless motor offers excellent efficiency, fast response and long-term durability compared with traditional brushed servo motors.

The servo supports 6.0V to 8.4V, making it suitable for modern HV receiver and power systems. At the maximum operating voltage of 8.4V, the A20-3813 delivers an impressive 43kg.cm of torque at just 0.12 sec/60°.

Torque and Speed

• 6.0V: 30kg.cm / 0.15 sec/60°

• 7.4V: 38kg.cm / 0.13 sec/60°

• 8.4V: 43kg.cm / 0.12 sec/60°

This combination of high torque and fast response makes the A20-3813 particularly well suited to demanding 3D aerobatics and large-scale precision aerobatic models.

Heavy-Duty Phosphor Bronze & Hardened Steel Gears

The A20-3813 uses a robust phosphor bronze and hardened steel gear train designed for high-load applications.

This heavy-duty gearing provides excellent resistance to wear and helps maintain precise control under the demanding loads generated by large control surfaces.

Combined with the powerful brushless motor and dual ball bearings, the result is a servo designed for serious RC aircraft applications where strength and reliability are critical.

CNC Aluminum Housing

The precision-machined aluminum case provides a rigid mounting platform while helping to dissipate heat generated during high-load operation.

The compact 40.5 × 20 × 38mm standard-size housing makes the A20-3813 easy to integrate into many large RC aircraft without requiring an oversized servo installation.

Ideal for Large-Scale Aerobatic & 3D Models

The KST A20-3813 V8.0 is an excellent choice for:

• Large-scale aerobatic RC airplanes

• 3D RC aircraft

• Giant-scale models

• Large Extra, Edge and Slick aircraft

• High-performance aerobatic models

• Large control surfaces

• Applications requiring high servo torque and fast response

If your model requires a powerful, fast and precise standard-size HV servo, the KST A20-3813 V8.0 offers an outstanding combination of torque, speed and durability.

Key Features

• 43kg.cm maximum torque at 8.4V

• 0.12 sec/60° speed at 8.4V

• High-performance brushless DC motor

• High-voltage operation from 6.0V to 8.4V

• Heavy-duty phosphor bronze & hardened steel gears

• Precision CNC aluminum alloy housing

• Dual ball bearings

• Standard-size 20mm servo case

• 25T / 6mm output spline

• 22AWG shielded connection cable

• Designed for large-scale and high-performance RC aircraft

Technical Specifications

Package Contents

• 1 × KST A20-3813 V8.0 Brushless HV Servo

• 1 × Servo Accessory Set

Recommended Application

For best performance, use the A20-3813 with a suitable HV receiver and power supply capable of safely delivering the required current. Always ensure that your receiver, power system and servo voltage are compatible before installation.

KST A20-3813 V8.0 – Maximum Power for Large RC Aircraft

When your large RC aircraft demands high torque, fast response and precise control, the KST A20-3813 V8.0 is built to deliver. Its 43kg.cm torque, brushless motor, heavy-duty metal gears and CNC aluminum housing make it a powerful choice for serious large-scale and 3D RC aircraft.