KST CM4315 V6.0 HV Digital Servo – 43kgf.cm High-Torque Steel Gear Servo
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:
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Ailerons
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Elevators
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Rudders
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Flaps
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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
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6.0V: 30kg.cm / 0.15 sec/60°
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7.4V: 38kg.cm / 0.13 sec/60°
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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:
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Large-scale aerobatic RC airplanes
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3D RC aircraft
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Giant-scale models
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Large Extra, Edge and Slick aircraft
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High-performance aerobatic models
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Large control surfaces
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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
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43kg.cm maximum torque at 8.4V
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0.12 sec/60° speed at 8.4V
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High-performance brushless DC motor
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High-voltage operation from 6.0V to 8.4V
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Heavy-duty phosphor bronze & hardened steel gears
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Precision CNC aluminum alloy housing
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Dual ball bearings
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Standard-size 20mm servo case
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25T / 6mm output spline
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22AWG shielded connection cable
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Designed for large-scale and high-performance RC aircraft
Technical Specifications
| Specification | KST A20-3813 V8.0 |
|---|---|
| Model | A20-3813 V8.0 |
| Servo Type | Digital HV Brushless Servo |
| Motor Type | Brushless DC Motor |
| Operating Voltage | DC 6.0V – 8.4V |
| Rated Voltage | DC 7.4V |
| Torque @ 6.0V | 30kg.cm |
| Torque @ 7.4V | 38kg.cm |
| Torque @ 8.4V | 43kg.cm |
| Speed @ 6.0V | 0.15 sec/60° |
| Speed @ 7.4V | 0.13 sec/60° |
| Speed @ 8.4V | 0.12 sec/60° |
| Gear Material | Phosphor Bronze & Hardened Steel |
| Case Material | CNC Aluminum Alloy |
| Bearings | 2 Ball Bearings |
| Output Spline | 25T / 6mm |
| Default Travel | ±50° / 100° total |
| Working Frequency | 1520μs / 333Hz |
| Operating Temperature | -10°C to +65°C |
| Dimensions | 40.5 × 20 × 38mm |
| Weight | 72g ±10% |
| Cable | 22AWG Shielded Cable |
Package Contents
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1 × KST A20-3813 V8.0 Brushless HV Servo
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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.
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KST A20-3813 V8.0 Brushless HV Servo with 43kg.cm torque and 0.12sec/60°. Heavy-duty phosphor bronze & hardened steel gears for large-scale RC aircraft and 3D aerobatic models.
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Shipping Costs & Delivery Information
We ship throughout Europe using PostNL and DHL, depending on the parcel size and destination. All shipments are fully insured for added peace of mind.
Shipping costs depend on your delivery country and, for large aircraft, the model's dimensions and size.
🇳🇱 Netherlands
Shipping categoryEstimated deliveryCostStandard parcels1–2 business days€7.95Parcels requiring special handling1–2 business days€19.50–€24.50Large parcels (15–30 kg)1–2 business days€59.00Heavy parcels (30–50 kg)1–2 business days€89.00
🇪🇺 International Standard Shipping
For standard parcels outside the Netherlands, shipping costs depend on the destination country and parcel size.
DestinationStandard shipping fromBelgium & Germany€13.50Other EU countries€16.95Switzerland & Norway€25.00Northern Ireland€19.00
✈️ Large Aircraft Shipping
Large model aircraft require special shipping due to their oversized boxes. The applicable rate depends on the model's wingspan and dimensions.
Model size / categoryShipping cost1.6–2.0 m wingspan€39.95–€49.502.0–2.3 m wingspan€89.002.3–2.6 m wingspan€115.002.6–2.9 m wingspan & small jets€145.00Over 2.9 m & large jets€240.00
Large aircraft are shipped using specialised transport services, including DHL where applicable. All large-aircraft shipments are fully insured.
Delivery Times
- Netherlands: 1–2 business days for standard shipments.
- Belgium & Germany: typically 1–5 business days, depending on the shipping category.
- Other European destinations: typically 3–8 business days.
Delivery times are estimates and may vary depending on the destination, carrier and parcel dimensions.
Important Information
- All shipments are fully insured.
- Final shipping costs are calculated at checkout where available.
- Large aircraft may be subject to special shipping rates based on their dimensions.
- If a separate shipping quote is required, we will confirm the applicable cost before shipment.
- Import duties, taxes and customs charges may apply to shipments outside the EU.