Futaba S-A301 Standard Digital RC Servo 9kg 0.13s FUT05102733-3

Overview

The Futaba S-A301 Standard Digital Servo PWM/S.BUS2 represents a precision control solution for RC aircraft enthusiasts across the UK. This compact coreless digital servo is engineered specifically for aeroplane applications, delivering the reliability and responsiveness that serious RC pilots demand. Whether you're flying fixed-wing aircraft, gliders, or UAV platforms, the S-A301 provides the centring accuracy and consistent torque output needed for stable, controlled flight. Its support for both conventional PWM and modern S.BUS2 protocols makes it compatible with a wide range of RC radio systems, from traditional transmitters to the latest digital control platforms used by RC aeroplane enthusiasts throughout the UK and beyond.

What sets the Futaba S-A301 apart in the standard servo category is its combination of lightweight engineering and robust metal gear construction. At just 47 grams, this servo minimises weight penalty on your aircraft whilst delivering a respectable 9.0 kg/cm of torque at 7.4V. The coreless motor design reduces inertia and improves responsiveness, allowing for quicker command translation and more precise control inputs. This is particularly valuable in RC aeroplane applications where smooth, accurate servo movement directly translates to better flight characteristics and handling. The S-A301 fills the sweet spot between budget-conscious builds and high-performance requirements, making it an excellent choice whether you're upgrading an existing RC aeroplane or building a new model from scratch.

RC enthusiasts in the UK seeking reliable, proven servo technology will appreciate Futaba's heritage of over 60 years in radio control. The S-A301 is manufactured to the same exacting standards that have made Futaba a trusted name in RC aircraft control, and it comes backed by genuine customer support through authorised UK retailers. When you choose the S-A301 for your next aeroplane project, you're investing in a servo that will deliver consistent, predictable performance flight after flight.

Key Features

• Dual Protocol Support (PWM and S.BUS2) — This servo accepts both conventional PWM signals and modern S.BUS2 digital protocols, ensuring compatibility with virtually any RC transmitter system used in the UK hobby market today. This flexibility means you can use the S-A301 with your existing radio setup or future upgrades without needing to replace the servo.
• Coreless Digital Motor — The coreless motor design dramatically reduces rotational inertia compared to traditional brushed servo motors, resulting in faster response times and more precise command tracking. This engineering choice translates directly to improved aeroplane handling and flight control responsiveness, especially important during manoeuvres that demand quick servo movement.
• Metal Gear Train with Bearing Support — The servo features a full metal gear drive with multiple stages (2-3 stage metal gearing) and bearing support in the final aluminium gear stage. Metal gears deliver superior durability and backlash resistance compared to plastic alternatives, ensuring your servo maintains precision control even after extended use. The bearing support reduces mechanical wear and extends operational lifespan.
• Exceptional Speed Performance — Operating at 0.13 seconds per 60-degree movement at 7.4V, the S-A301 ranks among the fastest servos in the standard size category. This rapid transit time enables more responsive flight control inputs and is particularly beneficial for aerobatic flying, precision approaches, and applications demanding quick control surface deflection.
• Compact Standard Size Dimensions — Measuring just 40 × 20 × 38.1 mm and weighing only 47 grams, the S-A301 is compact enough to fit in tight RC aeroplane fuselages and wing root installations without excessive space requirements. Its lightweight profile is critical for maintaining proper aircraft weight and balance characteristics whilst still delivering full control authority.
• Wide Voltage Operating Range — The servo operates reliably across the 4.8V to 7.4V voltage spectrum, making it compatible with 1S, 2S, and 3S lithium polymer batteries as well as traditional NiMH battery packs. This flexibility allows you to optimise your aircraft power system around your specific flying needs without servo compatibility concerns.
• 25-Tooth Metal Spline — The servo features a standard 25-tooth metal spline with 6mm diameter, ensuring secure horn attachment and reliable control surface linkage. The metal spline construction resists stripping and provides dependable mechanical connection between servo and control surfaces.

Technical Performance

The Futaba S-A301 delivers impressive technical performance metrics that position it as a serious option for RC aeroplane applications throughout the UK. The coreless digital motor architecture enables the servo to achieve 0.13 seconds per 60-degree movement at maximum voltage (7.4V), with slightly slower but still respectable 0.14 seconds per 60-degree performance at 6.0V. This speed differential allows you to optimise performance based on your specific power system configuration. Torque output reaches 9.0 kg/cm at 7.4V and 8.5 kg/cm at 6.6V, providing ample force for controlling ailerons, elevators, rudders, and flaps on most RC aeroplane designs from trainer platforms through to high-performance aerobatic models. The metal gear train construction, featuring 2-3 stages of precision-cut metal gears with bearing support on the final aluminium stage, ensures durability and maintains tight tolerances even under sustained use. The servo's digital circuit processing enables tight centring accuracy and smooth response characteristics that are essential for stable flight control. The 47-gram weight is remarkably light for a servo delivering this level of performance, making it ideal for weight-conscious aircraft designs where every gram matters for flight characteristics and battery endurance. Whether you're building a delicate flying wing, a traditional high-wing trainer, or a sleek composite aerobatic platform, the S-A301 provides the control precision and reliability demanded by modern RC aeroplane enthusiasts.

What's in the Box

• 1x Futaba S-A301 Standard Digital Servo
• Servo horns (multiple designs for different control surface types)
• Mounting hardware and fasteners

Frequently Asked Questions

• Is the Futaba S-A301 suitable for RC aeroplane beginners? — Yes, absolutely. The S-A301 is an excellent choice for builders at all experience levels. Its reliable performance, straightforward installation, and dual protocol compatibility (both traditional PWM and modern S.BUS2) make it equally at home in a simple trainer aeroplane or a high-performance competition model. The included servo horns and mounting hardware make installation straightforward, and the coreless motor provides smooth, responsive control that actually helps beginner pilots develop better flying skills by delivering predictable, precise command response.
• What voltage battery should I use with the S-A301? — The S-A301 operates across a wide 4.8V to 7.4V range, giving you excellent flexibility. This means you can use 1S LiPo batteries (3.7-4.2V nominal), 2S LiPo packs (7.4-8.4V nominal), traditional 6V or 7.2V NiMH battery packs, or even 6V alkaline cells if running a very simple trainer aeroplane. For maximum performance (0.13 seconds per 60 degrees), use 7.4V power; for lower-speed, lower-power applications, 4.8-6.0V provides adequate performance with reduced current draw and longer runtime.
• What is the difference between PWM and S.BUS2 protocol, and why does it matter? — PWM (Pulse Width Modulation) is the traditional RC servo control signal used by virtually every RC transmitter ever made. S.BUS and S.BUS2 are digital protocols developed by Futaba that transmit multiple servo commands through a single signal wire, reducing wiring complexity and enabling advanced features like telemetry. The S-A301's dual compatibility means you can use it with any modern Futaba S.BUS2-compatible transmitter for simplified wiring, or fall back to PWM mode with any standard RC radio. This flexibility ensures your servo investment remains current-proof regardless of future radio system choices.
• How does the coreless motor compare to traditional brushed servo motors? — Coreless motors eliminate the rotating commutator assembly found in brushed designs, significantly reducing rotational inertia and improving response speed. This enables faster command response (0.13 seconds vs. typical 0.17-0.20 seconds in many brushed servos) and smoother control without the micro-vibrations sometimes present in brushed designs. For RC aeroplane control, this translates to more precise trimming, more responsive flight control, and better overall aircraft handling characteristics. The coreless design does require slightly more careful installation to avoid reverse polarity (which can damage the electronics), but the performance benefits more than justify this minor consideration.
• Is 47 grams light enough for my RC aeroplane design? — Yes, the S-A301's 47-gram weight is genuinely lightweight for a servo delivering this level of performance and torque. For context, servos delivering comparable torque typically weigh 50-70 grams, making the S-A301 an excellent choice if your aircraft design has tight weight budgets. The lightweight characteristic is particularly valuable for parkflyer-sized trainers, flying wings, and other weight-sensitive designs where minimising servo weight helps maintain proper balance and maximises endurance.
• What control surfaces can the S-A301 handle? — The 9.0 kg/cm torque output at 7.4V provides ample force for ailerons, elevators, and rudders on aeroplane models ranging from small trainers through to large-scale sport models. For heavier aerobatic models or larger control surfaces, particularly large rudders on high-speed designs, you may want to consider stacking two S-A301 servos or upgrading to a higher-torque servo. For flap control on trainers and sport flyers, the S-A301 is more than adequate and gives you responsive flap authority without excessive weight penalty.
• What is the 25-tooth spline and why does it matter? — The spline is the mechanical interface between the servo output shaft and the control horn you attach to your servo. The S-A301 features a standard 25-tooth spline with 6mm diameter, which is the most common servo spline size used in RC aeroplane applications throughout the UK and worldwide. This universal standard means you have access to countless horn options from multiple manufacturers, and you can easily swap horns or transfer the servo between different aircraft models. The metal construction of the S-A301's spline resists stripping and provides rock-solid mechanical connection to your control horn.

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-A301 Standard Digital Servo PWM/S.BUS2 9kg 0.13s 4.8V - 7.4V FUT05102733-3 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.