FUT05102673-1

Overview

The Futaba S-U301 Standard Digital Servo is a high-performance digital servo designed for RC aircraft and precision applications where reliability and control are paramount. This compact yet powerful servo delivers exceptional performance in a lightweight package, making it an ideal choice for anyone building or upgrading their RC model aircraft. Whether you're an experienced RC enthusiast in the UK looking to enhance your aircraft's control surfaces or a dedicated hobbyist seeking dependable servo technology, the S-U301 offers the precision control and durability that Futaba is renowned for worldwide.

Featuring full digital architecture with support for multiple command protocols including PWM, S.BUS, and S.BUS2, this servo integrates seamlessly into modern RC systems while maintaining backward compatibility with traditional PWM-only receivers. The S-U301 represents the perfect balance between performance, size, weight and affordability, making it suitable for a wide range of aircraft types from trainer planes to sport aircraft and everything in between. At just 36 grams, this servo delivers surprising power without adding unnecessary weight to your airframe.

Built by Futaba, a company that has been leading the way in radio control technology since 1962, the S-U301 carries the heritage and expertise of one of the most trusted names in the RC hobby. With over 50 years of experience in servo design and manufacturing, Futaba continues to set the standard for quality and performance in the RC industry across the UK and beyond.

Key Features

• Digital Architecture — The S-U301 is a fully digital servo, which means it offers superior precision, repeatability and linearity compared to analogue servos, allowing your RC aircraft to maintain exact control positions even in challenging flight conditions and ensuring your model responds exactly as you programme it.
• Multiple Protocol Support — This servo supports PWM, S.BUS, and S.BUS2 command protocols, giving you complete flexibility in receiver choice and allowing you to upgrade your radio system without needing to replace your servos or retrofit different hardware.
• Exceptional Speed — With a response time of just 0.16 seconds per 60 degrees at 7.4V, the S-U301 delivers lightning-fast servo response that translates into crisp, immediate control input feedback, essential for dynamic flight manoeuvres and maintaining precise aircraft attitude control.
• Strong Torque Output — Producing 3.9 kgf·cm of torque at 7.4V (or 3.5 kgf·cm at 6.6V), this servo has more than enough power to move control surfaces on standard aircraft, handle aerodynamic loads during flight, and maintain position against wind pressure and aerodynamic forces.
• Durable Plastic Gearing — The S-U301 features resin gearing with a 25-tooth spline at 6mm diameter, engineered to provide smooth, consistent operation whilst remaining lightweight and offering excellent durability for extended flying seasons.
• 3-Pole Cored Motor — The advanced motor design delivers smooth power delivery, reduced noise during operation and efficient energy consumption, meaning longer flight times and quieter operation compared to cheaper servo alternatives.
• Wide Voltage Compatibility — Operating across 4.8V to 7.4V, the S-U301 works with standard 4-cell NiMH receiver packs, 2-cell LiPo batteries, or any voltage receiver battery configuration within this range, offering excellent flexibility for your power system.
• Compact Dimensions — Measuring just 40.5×20×36.1mm, the S-U301 is a standard-size servo that fits into most conventional servo bays, allowing easy installation into both new builds and existing aircraft without requiring airframe modifications.
• Lightweight Design — At only 36 grams, this servo adds minimal weight to your aircraft, leaving more available weight budget for fuel, batteries, larger control surfaces or additional equipment, a critical consideration for any RC aircraft builder.
• Complete Accessory Pack — The servo comes with servo horns and mounting hardware included in the box, meaning you can start installation immediately without purchasing additional accessories or hunting for compatible parts.

Technical Performance

The Futaba S-U301 represents a carefully engineered balance of performance, weight and cost that makes it an outstanding choice for RC aircraft applications. The servo's 3-pole cored motor design ensures smooth, consistent torque delivery across the entire servo travel range, eliminating the stuttering or hesitation that can occur with cheaper motor designs. Operating on a fully digital circuit architecture, the S-U301 provides superior linearity and repeatability compared to analogue servo alternatives, meaning your control inputs are translated into exact physical movements every single time, critical for maintaining stable, predictable flight characteristics. The servo's resin plastic gearing with 25-tooth, 6mm diameter spline has been engineered for the perfect compromise between durability and weight, offering smooth operation whilst keeping overall servo mass to an absolute minimum. This is crucial in aircraft applications where every gram of weight directly impacts climb performance, flight duration and manoeuvrability. With dual voltage capability spanning 4.8V through 7.4V, the S-U301 accommodates virtually any receiver power configuration used in RC aircraft today, whether you're using traditional 4-cell NiMH packs or modern 2-cell LiPo batteries. The response time of 0.16 seconds per 60 degrees at 7.4V puts this servo firmly in the performance category, delivering the snappy control response that experienced pilots expect and depend upon for precision flying. When powered at 6.6V, response time increases slightly to 0.18 seconds per 60 degrees, with torque reducing to 3.5 kgf·cm, a trade-off that may be acceptable if your power system operates at this voltage. The multi-protocol command support ensures this servo will work seamlessly with modern Futaba receivers supporting PWM, S.BUS, or S.BUS2 connectivity, whilst also maintaining full compatibility with any standard PWM-only receiver for maximum system flexibility.

What's in the Box

• 1x Futaba S-U301 Standard Digital Servo
• Servo horns for standard control surface installation
• Mounting hardware for secure airframe installation

Frequently Asked Questions

• Is the Futaba S-U301 suitable for beginner RC aircraft builders? — Yes, absolutely. This servo is ideal for beginners because it offers excellent reliability, straightforward installation, and works with both modern digital receivers and traditional PWM systems. The included horns and mounting hardware mean you can start building immediately, and the servo's forgiving torque characteristics won't damage your airframe even if you make minor setup mistakes. Its reasonable price point also makes it an excellent entry-level choice for those just starting their RC aircraft journey.
• What voltage battery should I use with the S-U301? — The S-U301 operates between 4.8V and 7.4V, which covers most common receiver power options in RC aircraft applications. You can use a 4-cell 1700mAh NiMH receiver pack at approximately 4.8V nominal voltage, or a 2-cell LiPo battery at 7.4V fully charged. For absolute maximum performance and response speed, a 2-cell LiPo at 7.4V is recommended, as this delivers the servo's fastest response time of 0.16 seconds per 60 degrees and highest torque of 3.9 kgf·cm.
• Can I use the S-U301 with my existing PWM receiver? — Yes, the S-U301 fully supports traditional PWM protocol alongside S.BUS and S.BUS2, making it compatible with virtually all modern and legacy Futaba receivers. This backward compatibility means you can upgrade your servos without being forced to upgrade your entire radio system simultaneously.
• How does the S-U301 compare to other standard-size aircraft servos? — The S-U301 offers exceptional value through its combination of digital architecture, multi-protocol support, fast response time, and strong torque output, all packaged in a lightweight design. Many competing servos at similar price points offer either slower response times or reduced torque output. The inclusion of Futaba's decades of servo engineering expertise and the reputation for reliability makes the S-U301 a smart investment for any RC aircraft enthusiast in the UK.
• Is this servo waterproof or weather-resistant? — The S-U301 is not specifically rated as waterproof, so it should be protected from heavy rain, water immersion or spray. However, for typical outdoor RC flying where the aircraft is exposed to normal atmospheric moisture, the servo will perform reliably. If you anticipate flying in wet conditions or near water, consider protecting your servo bay with sealant or using dedicated waterproof servos designed for such applications.
• What is the difference between this servo and the previous generation Futaba servos? — The S-U301 represents current Futaba technology with full digital circuitry, multi-protocol support including the latest S.BUS2 standard, and optimised performance parameters developed through years of real-world aircraft flying. Previous generation servos may lack S.BUS2 compatibility or feature analogue rather than digital circuitry, both of which provide advantages in modern RC systems.

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-U301 Standard Digital Servo PWM/S.BUS2 3.9kg 0.16s 4.8v - 7.4V FUT05102673-1 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.