ISNE Bélos
| ISNE Bélos | |
|---|---|
| |
| Belos in prototype camouflage | |
| Role | air superiority fighter |
| National origin | Willink |
| Manufacturer | Institoúto Stratigikón Naftikón Erevnó |
| First flight | 7 June 2021 |
| Introduction | Q2 2025 |
| Status | In development |
| Primary user | Willink |
| Produced | 2025- |
| Number built | 12 |
The ISNE Bélos is a sixth-generation air dominance fighter in development by Willinkian defense contractor Institoúto Stratigikón Naftikón Erevnó. The Bélos is designed to replace aging fourth-generation aircraft (the Questarian Dauntless and Shrike) and augment the multirole Bantam in Willinkian air service, as well as replace the F/A-77 Kovas/Havenfighter as the primary air dominance fighter in Willinkian use; the latter is to be adapted to a multirole/strike role. Initially conceptualized in 2014 as ISNE worked on missile block and cockpit support system updates for the Havenfighter, the Bélos undertook its first flight in 2021, and is scheduled to reach initial operation in early 2025. In air defense, the Bélos is intended to out-class its regional competitors and legacy platforms such as the Project 352 Nukefighter, Supermarine Sea Kestrel (Libertyfighter), and F-23 Helios (Setofighter).
Development
ISNE, under its anglicized trade name Strategic Naval Research Institute was a development partner with ARES Group on the F/A-77 Kovas, also known as the Havenfighter, being tasked with cockpit support systems and weapon system integration generally , one of two Willinkian manufacturers involved with the project alongside Gloucester Aviation. Further, in Willinkian examples of the aircraft, ISNE took on a greater role in systems integration, translation of software into native Willinkian, as well as designing a large percentage of the dedicated missile platforms carried by the plane in Willinkian service. Thereafter, it maintained an important localized role in maintenance and service upgrades, having close access to the production process, as well as test-bed aircraft to prototype and integrate new systems. In 2014, amid system upgrades intended to integrate the new Cheiron Block II SRAAM, ISNE started conceptualizing a successor craft to the Kovas, based on feedback from Willinkian pilots operating the platform, as well as their own experience with the plane's electrical and cockpit management systems.
Generally, the Kovas is a highly regarded platform by pilots, capable of (arguably) best in class maneuverability, stability at both low and high speeds, a complex, effective, powerful sensor suit, and possessing high survivability. However, several persistent issues were identified: the modular dual-layer RAM system required frequent inspections and replacements, especially in harsh environments like naval operations; at speeds above Mach 1.5–1.8, the Kovas RAM and composite materials over its lifespan tended to degrade due to aerodynamic heating, reducing stealth performance; the Kovas struggled with heat dissipation due to its powerful radar and engine, leading to IR detection risks and operational inefficiency; and the Kovas skin panels were designed for specific operational wavelengths, limiting adaptability to emerging threats with different radar bands or advanced detection methods. Combat experience with the aircraft demonstrated that the diamond wing and large canards of the Kovas would exacerbate drag and airflow disruption at slow speeds, reducing stability in dogfights or low-speed engagements or at extreme angles of attack. Finally, over time, as systems were upgraded (e.g., avionics, sensors, weapons), the airframe's weight and radar cross-section (RCS) would increase, negatively impacting its stealth profile and agility; the "future proofing" of the Kovas was under increasing strain with improvements made in machine learning and computing power, stressing the power supply systems in an already complex, electrically demanding aircraft.
Design
Aerodynamics
The Bélos sought to improve lift-to-drag ratios while maintain low observability, opting for a cranked-kite wing layout. The aircraft retains a similar rear layout to the Kovas, opting for a v-tail. The Bélos mounts diamond-shaped canards as frontal control surfaces. This cranked-kite-v-tail-canard configuration was selected for its high AoA performance, excellent post-stall maneuvering, excellent yaw and pitch controls, and adaptability to both supersonic and subsonic regimes. At high speeds, the cranked-kite wing reduces wave drag, while at low speeds, canard-assisted vortex lift improves control and stability for landing or dogfighting. The combination of cranked-kite wings and canards ensures excellent longitudinal stability, even in scenarios where the aircraft's center of gravity shifts (e.g., as fuel is expended or weapons are deployed). The V-tail reduces cross-sectional drag while maintaining effective control authority for pitch and yaw, particularly important during high-speed flight. This configuration strikes a balance between stealth, maneuverability, and efficiency. Compared to other configurations, it offers superior multi-role performance by blending stealth optimization with aerodynamic versatility, enabling operations in high-threat environments against advanced radar and missile systems. The inclusion of canards and V-tail enhances agility and control, making it a more robust platform for high AoA and post-stall maneuvers. While it may not achieve the extreme stealth of a tailless design or the simplicity of a conventional wing-tail configuration, it is a well-rounded choice for scenarios demanding both survivability and dominance in contested airspaces.
The Bélos is set up in a configuration reminiscient of the Saab Viggen; its wings mounted nearly flush to the lower fuselage, minimizing the frontal radar cross-section (RCS) by reducing exposed edges and surfaces; above-wing engine intakes, mounted on the lower half of the fuselage and blended into the body line via a leading-edge extension; and canards mounted on the intakes above the wing. The loss of airflow beneath the aircraft, particularly during low-speed, high-angle-of-attack (AoA) conditions by the wing placement is mitigated by intake and canard placement generating vortex lift at high AoA. This layout blends stealth, high-AoA stability, better lift-to-drag ratios, and superior airflow control to the airframe.
Aerodynamically, the positioning of the engines and V-tail imposes specific challenges and opportunities. The "humped" engine integration creates a broader fuselage cross-section, which can slightly increase drag, but it can also improve lift by contributing to the lifting body effect of the fuselage itself. Furthermore, the outward placement of the V-tail stabilizers enhances yaw and pitch stability by increasing the moment arm relative to the center of gravity. This configuration synergizes well with the diamond-shaped canards and cranked-kite wing, as the canards improve maneuverability and stability at high angles of attack, while the cranked-kite wing offers strong lift-to-drag ratios and low-speed stability. The V-tail's upward and outward angling also contributes to minimizing interference with the airflow over the wings and canards, ensuring smoother aerodynamics overall.
In terms of systems integration, the positioning of the V-tail and engines impacts the internal structure and layout of subsystems. The outward V-tail placement allows for more streamlined heat and airflow management around the engines, improving thermal dissipation and reducing the risk of thermal hotspots that could compromise stealth or operational efficiency. However, this arrangement requires precise engineering of control linkages and structural reinforcements to handle the aerodynamic loads transferred through the extended stabilizers during high-speed or high-G maneuvers.