Futaba S-U300 Standard Digital Servo PWM S.BUS2 4.1kg 0.19s FUT05102671-1

Overview

The Futaba S-U300 Standard Digital Servo is a professional-grade standard-size servo designed specifically for RC aircraft and fixed-wing models. Whether you're building a trainer aircraft, sport plane, or high-performance glider, this servo delivers the precision control and reliability that RC pilots across the UK demand. As an authorised Futaba retailer, RC Model Shop stocks this genuine servo, which represents excellent value for serious RC enthusiasts looking for a dependable control surface actuator without breaking the bank.

This is a digital servo with support for both traditional PWM and modern S.BUS2 protocols, making it compatible with virtually all contemporary RC radio systems available in the UK market. The S-U300 combines proven Futaba engineering with practical features like plastic gearing, a robust 3-pole cored motor, and a compact footprint that won't add excessive weight to your aircraft. At just 36 grams, it's light enough for scale models and sport aircraft whilst maintaining sufficient torque for reliable control authority in challenging flying conditions.

If you're searching for an affordable yet capable standard servo for your next RC plane UK project, or you need a direct replacement for an existing servo that's reached the end of its service life, the S-U300 is a sensible choice that won't disappoint. Futaba has been leading the way in radio control since 1962, and this servo embodies decades of expertise in RC servo design and manufacture.

Key Features

• S.BUS2 Protocol Support — This servo is fully compatible with S.BUS2, Futaba's advanced digital command protocol, which enables telemetry feedback and allows multiple servos to be controlled through a single data line, simplifying wiring in complex aircraft builds and reducing overall system weight and complexity.
• PWM Compatibility — In addition to S.BUS2, the S-U300 supports traditional PWM control, ensuring you can use it with any standard RC receiver from any manufacturer, making it an incredibly versatile choice whether you're upgrading older aircraft or building new ones.
• Plastic Gearing with 6mm/25T Spline — The servo features durable plastic gearing with a standard 6mm diameter, 25-tooth output spline, which is the universal standard for RC aircraft servos, ensuring compatibility with virtually all aircraft control horns and linkage hardware available for purchase in the UK and internationally.
• 3-Pole Cored Motor — The high-quality 3-pole cored motor design provides smooth, consistent operation with excellent linearity, meaning control inputs translate predictably to control surface movement without dead zones or binding, critical for precision flying and aerobatic manoeuvres.
• Dual Voltage Operation — Operating across the 4.8V to 6.0V range, this servo is compatible with both 4-cell NiMH receiver batteries and 2-cell LiPo receiver packs, offering flexibility in your power system design and allowing you to choose the battery chemistry that best suits your needs.
• Ultra-Compact Dimensions — Measuring just 40.4 × 19.8 × 36.0mm, the S-U300 fits in tight spaces and minimises the footprint needed for servo installation, leaving more room for other components and helping you achieve better weight distribution in your RC aircraft.
• Lightweight Construction — At only 36 grams, this servo adds minimal weight to your aircraft, preserving battery runtime, improving climb performance, and helping you stay within weight limits for competition flying or scale accuracy in RC aircraft UK projects.

Technical Performance

The Futaba S-U300 delivers impressive performance across a range of operating voltages. At 6.0V, the servo achieves a transit speed of 0.19 seconds per 60 degrees of rotation, paired with a maximum torque output of 4.1 kilogram-force centimetres (56.9 ounces-force per inch), providing rapid control surface actuation for responsive aircraft handling. When operating at 4.8V from a standard NiMH receiver battery, the servo produces a slightly more leisurely 0.23 seconds per 60 degrees with 3.2 kilogram-force centimetres of torque (44.4 ounces-force per inch), still more than adequate for most training aircraft and sport flyers. The digital circuit board ensures precise, repeatable movements with minimal hunting or oscillation, whilst the 3-pole cored motor provides the smooth power delivery necessary for natural-feeling control inputs. The plastic gearing offers a good balance between weight savings and durability, suitable for the relatively modest control forces encountered in most RC aircraft applications. The servo's engineering reflects Futaba's half-century-plus of experience in the RC industry, with components designed to withstand the vibration, temperature variations, and operational stresses inherent in aircraft flying. Whether mounted in the fuselage, wing, or tail section of your RC plane, the S-U300 will provide reliable service across countless flights.

What's in the Box

• 1x Futaba S-U300 Standard Digital Servo
• Servo horns (multiple options for different control surface applications)
• Mounting hardware (screws and brackets for installation)

Frequently Asked Questions

• What type of RC aircraft is the Futaba S-U300 suitable for? — The S-U300 is classified as a standard-size servo, making it ideal for small to medium RC aircraft including trainers, sport planes, slope soarers, and RC gliders. It's particularly well-suited to fixed-wing models where lightweight, responsive control is required without the need for extreme torque typical of aerobatic high-performance machines.
• Is the S-U300 compatible with my existing RC radio system? — Yes. The S-U300 supports both traditional PWM control and modern S.BUS2 protocols. If your RC radio supports any of these protocols, this servo will work. PWM compatibility means it will work with virtually any RC receiver from any manufacturer sold in the UK market, including Spektrum, Hitec, Graupner, and many others.
• What battery voltage does this servo need? — The S-U300 operates across a range from 4.8V to 6.0V. This means it's compatible with 4-cell NiMH batteries (nominally 4.8V) commonly used in RC receiver packs, and 2-cell LiPo batteries (nominally 7.4V, but with voltage regulation). For best performance and fastest response, use 6.0V when possible.
• What torque does the S-U300 produce? — At 6.0V maximum voltage, the servo produces 4.1 kilogram-force centimetres of torque, equivalent to 56.9 ounces-force per inch. This is sufficient for control surface actuation in most RC aircraft. At 4.8V, torque reduces to 3.2 kilogram-force centimetres (44.4 ounces-force per inch), still adequate for standard applications.
• How fast is this servo? — At 6.0V, the S-U300 completes a 60-degree movement in 0.19 seconds, making it a quick servo suitable for responsive aircraft control. At 4.8V, the speed is 0.23 seconds per 60 degrees, still respectable for most flying applications.
• Is the S-U300 suitable for beginners? — Absolutely. This is a standard servo designed for general-purpose aircraft use, and whilst it's a quality Futaba product built to professional standards, it's affordable and straightforward to install and operate. If you're new to RC aircraft in the UK, the S-U300 is an excellent choice that won't frustrate you with complexity or unreliability.
• What spline size does the S-U300 use? — The servo has a standard 6mm diameter spline with 25 teeth, which is the universal standard for RC aircraft servos. This means you can source servo horns, bellcranks, and linkage hardware from any RC retailer in the UK without compatibility concerns.
• Is this servo waterproof? — The S-U300 is a standard digital servo with plastic gearing and is not specifically waterproof or sealed for water resistance. It is suitable for normal outdoor flying conditions but should not be submerged or exposed to heavy rain or spray. If you require water resistance for amphibious or water-landing applications, you may need to consider a specialised sealed servo.

Why Buy from RC Model Shop?

RC Model Shop is a trusted UK RC retailer and authorised dealer for all the brands we stock, including Traxxas, ARRMA, Losi, FTX, Hobbywing, Spektrum and more. Based in Walsall, we have a physical store where customers are welcome to come in, view products and purchase in store. Whether you are a seasoned competitor, a weekend basher, or just discovering the world of RC for the first time, our team of experienced RC enthusiasts is here to help you find the perfect setup and provide ongoing support. Order the Futaba S-U300 Standard Digital Servo PWM/S.BUS2 4.1kg 0.19s 4.8V - 6V FUT05102671-1 today with confidence, knowing you are buying from an authorised retailer with genuine products, expert knowledge and a commitment to customer satisfaction. Shop online or visit us in Walsall — we look forward to helping you get the most out of your RC experience.