SOURCE: AFI
In the 1980s, the Aeronautical Development Agency (ADA) embarked on an ambitious project to develop India’s Light Combat Aircraft (LCA), now known as the Tejas. To ensure a robust foundation, ADA contracted four renowned aircraft manufacturers—British Aerospace, Dassault Aviation, Dornier, and Messerschmitt-Bölkow-Blohm (MBB)—to conduct feasibility studies and propose the optimum configuration for the LCA. Each house suggested distinct designs, reflecting diverse engineering philosophies. Following a comprehensive normalization study, three primary configurations emerged as contenders: Aft Tail, Canard, and Tailless Delta. These designs shaped the evolution of the LCA and highlighted the complexity of balancing performance, stability, and manufacturability.
The Aft Tail configuration features a conventional layout with a single vertical stabilizer and horizontal tail surfaces located at the rear. This design, favored by some studies for its simplicity and proven stability, allows for effective control and maneuverability. It resembles traditional fighter aircraft, offering a reliable platform for integration with advanced avionics and weapons systems. The Aft Tail design was seen as a safe choice, leveraging established aerodynamic principles to ensure predictable flight characteristics.
The Canard configuration introduces a foreplane, or canard, ahead of the main wings, in addition to a rear tail. This layout, explored by manufacturers like Dassault, enhances lift and improves agility, particularly at low speeds and high angles of attack. The canard design provides better aerodynamic efficiency and control, making it suitable for a highly maneuverable combat aircraft. However, it requires sophisticated flight control systems to manage the complex airflow interactions between the canard and main wings.
The Tailless Delta configuration eliminates the traditional tail, featuring a large delta-shaped wing that integrates control surfaces. Advocated by some studies for its stealth potential and high-speed performance, this design reduces drag and improves fuel efficiency. The tailless delta offers excellent lift at high angles of attack, ideal for supersonic flight, but poses challenges in low-speed handling and stability, necessitating advanced fly-by-wire technology.
The normalization study conducted by ADA evaluated these configurations against criteria such as aerodynamic performance, structural integrity, and cost. The process culminated in the selection of a design that blended elements from these studies, leading to the Tejas’ eventual delta-wing configuration with a close-coupled canard influence. This hybrid approach reflects the collaborative insights of the four aircraft houses, laying the groundwork for India’s indigenous fighter jet program.
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