ROC HOBBY CRITICAL MASS FUSELAGE (HIGH SPEED) ROC-KT101-1

Overview

The ROC HOBBY CRITICAL MASS FUSELAGE (HIGH SPEED) ROC-KT101-1 represents a premium choice for RC aircraft enthusiasts seeking a high-performance racing fuselage component. This expertly engineered part is designed specifically for pilots who demand speed, precision and quality construction in their RC plane builds. Whether you're an experienced RC flyer looking to upgrade an existing model or someone building a high-speed racing aircraft from scratch, this fuselage provides the structural foundation you need for competitive performance. The Critical Mass designation speaks to the careful weight distribution and aerodynamic design that goes into every FMS component, ensuring that your RC aircraft UK setup achieves optimal balance and handling characteristics.

This fuselage is part of the comprehensive FMS parts ecosystem, which means it integrates seamlessly with a wide range of compatible components and accessories. The high-speed designation indicates this fuselage has been optimised for velocity and agile flight characteristics, making it ideal for racing applications and performance-oriented flying. RC model enthusiasts across the UK and beyond choose FMS components for their reliability, ease of assembly and proven performance in the field. Whether you're building your first high-speed aircraft or adding to an existing collection, this fuselage offers the quality and engineering that serious RC pilots expect.

As part of the extensive FMS 980mm P-39 platform, this fuselage benefits from decades of aircraft design knowledge translated into modern RC form. The Critical Mass series represents FMS's commitment to providing racers and performance enthusiasts with components that don't compromise on quality. This is a genuine, authorised FMS part that comes with full compatibility assurance across the P-39 platform, making it an excellent investment for anyone serious about high-speed RC aircraft flying.

Key Features

• High-Speed Optimised Design — The fuselage has been specifically engineered for racing and high-speed applications, with aerodynamic shaping that minimises drag whilst maintaining structural integrity at high velocities.
• Critical Mass Engineering — FMS's Critical Mass designation means careful attention has been paid to weight distribution, balance point and structural strength, ensuring your aircraft performs predictably across the entire flight envelope.
• 980mm Platform Compatibility — This fuselage is part of the established 980mm P-39 family, meaning you'll find extensive parts availability including wings, landing gear systems, stabilisers, cockpits and countless upgrade options readily available.
• Precision Construction — Built to FMS's exacting standards, the fuselage provides a solid foundation for mounting flight electronics, servo systems and other essential components with proper alignment and minimal vibration.
• Comprehensive Parts Ecosystem — Compatible with numerous FMS accessories including the 980mm P-39 Main Wing Set, Horizontal Stabilizer, Front and Main Landing Gear Systems, allowing you to build a complete aircraft or upgrade an existing model.
• Proven Platform — The P-39 platform has been thoroughly tested by RC enthusiasts worldwide, with established build techniques, setup guides and community support available to help you get the most from your aircraft.
• Professional Grade Quality — As an authorised FMS product, this fuselage meets the manufacturer's rigorous quality standards and comes with the assurance of genuine parts and proper customer support.

Technical Performance

The ROC HOBBY CRITICAL MASS FUSELAGE is engineered for the 980mm scale class, placing it in the intermediate-to-advanced category of RC aircraft. The fuselage forms the backbone of your aircraft assembly, requiring integration with a suitable power system. For aircraft of this class, FMS typically recommends the 3648 KV770 Motor (Long Shaft) paired with an 80A ESC featuring 220mm input cable and 4.0mm motor connector, though alternative powerplants may be compatible. The fuselage is designed to accommodate standard 9g digital metal gear servos, such as the versions offered with either positive or reverse rotation depending on your control surface requirements. Landing gear integration is straightforward, with both front and main landing gear systems available in standard or electronic retract configurations. The fuselage's structural design has been optimised to work with the 980mm P-39 Main Wing Set and Horizontal Stabilizer, creating a complete airframe platform. Build materials utilise proven composite techniques that balance weight with structural rigidity, critical for maintaining stability at racing speeds whilst keeping the overall aircraft light enough for responsive control. The high-speed designation means this fuselage has been refined through testing to produce minimal drag whilst maintaining the strength required for sustained high-velocity flight. Whether you're operating a standard fixed landing gear configuration or utilising electronic retracts for cleaner aerodynamics during cruise, this fuselage provides the foundation for a competitive racing platform. Decal sheets and custom cockpit options are available separately, allowing complete customisation of your finished aircraft's appearance.

What's in the Box

• ROC HOBBY CRITICAL MASS Fuselage (980mm scale, High Speed variant)
• Hardware and assembly fittings specific to fuselage construction

What You Need to Complete

• Main Wing Set (980mm P-39 compatible)
• Horizontal Stabilizer (980mm P-39 compatible)
• Landing Gear System (Front and Main options available in fixed or electronic retract)
• Motor (such as 3648 KV770 Long Shaft or compatible alternative)
• ESC (80A rated with appropriate connector for your motor choice)
• LiPo Battery (specifications depend on chosen motor and ESC pairing)
• Radio Control System (transmitter and receiver)
• Servos (9g digital metal gear servos in positive or reverse rotation as required)
• Propeller (such as 980mm P-39 10.5*8 size)
• Spinner (980mm P-39 compatible)
• Cockpit (980mm P-39 variant)
• Decal Sheet (for finished appearance)
• Linkage Rods and Screw Sets for assembly and control surface linkage

Frequently Asked Questions

• What is the 980mm scale and how does it compare to other RC aircraft? — The 980mm dimension refers to the fuselage length, placing this aircraft in the intermediate scale category that offers excellent handling characteristics and reasonable portability whilst maintaining enough size for quality construction and good visibility during flight. This size is popular for both recreational flying and racing applications.
• Is this fuselage suitable for beginner RC aircraft builders? — Whilst this fuselage is a quality component, building a complete RC aircraft requires some experience in assembly, electronics integration and flight setup. Beginners are advised to start with ready-to-run (RTR) aircraft or to seek guidance from experienced builders. However, if you're progressing from simple aircraft to this platform, you'll find the P-39 family offers extensive community support and building resources online.
• What motor should I use with this fuselage? — FMS recommends the 3648 KV770 Motor (Long Shaft) as the compatible option. This motor provides strong performance for racing applications whilst maintaining reliable operation. Always verify motor specifications match your chosen ESC rating and battery configuration before assembly.
• How does the Critical Mass fuselage differ from standard FMS P-39 fuselages? — The Critical Mass designation indicates this fuselage has been specifically optimised for high-speed racing performance, with enhanced aerodynamics and refined weight distribution compared to standard variants. This makes it the preferred choice for competitive racing environments where every performance advantage matters.
• What landing gear options are compatible? — Both the 980mm P-39 Front Landing Gear System and Main Landing Gear System are fully compatible. You can choose between fixed gear for simplicity or electronic retract options (980mm P-39 Front Landing Gear E-Retract) for cleaner aerodynamics during high-speed flight. Compatible with common electronic retract systems available in the P-39 accessory range.
• Can I use this fuselage to upgrade an existing aircraft? — Yes, if you currently own a 980mm P-39 variant, this high-speed fuselage can be a direct replacement, allowing you to upgrade to improved performance characteristics. Your existing wings, landing gear, motor and avionics will transfer over, though you'll need to ensure proper re-balancing after the swap.
• What flight control system is recommended? — The FMS Reflex V3 Stable Flight Controller integrates with the P-39 family and is suitable for RC aircraft generally, offering stabilised mode for confidence-building flight, optimised mode for enhanced handling, and manual mode for experienced pilots. This gyro system is not mandatory but is recommended for safety and learning.
• Where can I source compatible parts in the UK? — RC Model Shop stocks the extensive FMS parts ecosystem for the P-39 platform, including wings, stabilisers, landing gear, servos, motors, ESCs and accessories. All components are tested for compatibility and backed by authorised dealer support.

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 ROC HOBBY CRITICAL MASS FUSELAGE (HIGH SPEED) ROC-KT101-1 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.