SOURCE: AFI
In a candid admission, Dr. Samir V. Kamat, Chairman of the Defence Research and Development Organisation (DRDO), revealed that India’s Medium Altitude Long Endurance (MALE) and High Altitude Long Endurance (HALE) Unmanned Aerial Vehicle (UAV) programs face a critical bottleneck: the development of suitable propulsion systems, which could take another four to five years to mature.
This acknowledgment underscores a pressing need for the Aeronautical Development Establishment (ADE), a key DRDO laboratory, to intensify efforts on developing indigenous turboprop propulsion systems tailored to meet the stringent requirements of MALE and HALE UAVs. With regional rivals advancing their unmanned capabilities, India must prioritize this technological leap to bolster its aerial surveillance and combat potential under the Aatmanirbhar Bharat initiative.
The DRDO’s MALE and HALE UAV programs, critical for Intelligence, Surveillance, Target Acquisition, and Reconnaissance (ISTAR) missions, aim to deliver platforms with endurance exceeding 24 hours and operational ceilings above 30,000 feet (MALE) and 35,000 feet (HALE). However, as Dr. Kamat noted in a recent interview, the availability of suitable propulsion systems remains a “major challenge,” with current technology readiness levels (TRL) at 5, targeting TRL 7 within five years. Unlike smaller drones, where India has demonstrated indigenous design capabilities, MALE and HALE UAVs require advanced propulsion to handle heavy payloads (up to 2 tonnes for HALE) and operate efficiently at high altitudes, where piston engines falter due to drag and power limitations.
Turboprop engines, known for their reliability and fuel efficiency at high altitudes, are the preferred choice for these platforms. The DRDO’s HALE UAV, a 5-tonne platform with a 2-tonne payload and over 25 hours of endurance, is designed to rely on a turboprop engine, with General Atomics providing consultancy to validate systems. Similarly, the MALE Archer-NG, a weaponized UAV with a 30,000-foot ceiling and 300 kg payload, requires robust propulsion to integrate smart anti-airfield weapons and anti-tank guided missiles. However, India’s reliance on foreign engines, such as the Austro Engine E4 for the TAPAS-BH-201 prototype, highlights a gap in indigenous capability that must be addressed urgently.
The ADE has made strides in UAV development, from the Nishant and Rustom series to the TAPAS-BH-201, but none have fully met the Indian Armed Forces’ stringent requirements for altitude and endurance. The TAPAS-BH-201, powered by twin NPO-Saturn 36MT turboprops (100 hp each) in prototypes and planned for indigenous 220 hp engines from the Vehicle Research and Development Establishment (VRDE), failed to achieve the Joint Services Qualitative Requirements (JSQRs) of 30,000 feet and 24-hour endurance, leading to its closure as a mission-mode project in January 2024. This setback underscores the critical role of propulsion in meeting operational demands.
ADE’s latest initiative involves establishing a dedicated test bench for turboprop engines, a significant step to validate performance, reliability, and integration into next-generation UAVs. Engineers are assessing thrust, fuel consumption, and thermal efficiency to ensure military-grade standards. Additionally, VRDE is developing 180 hp and 220 hp indigenous engines for MALE UAVs like Archer-NG, with taxi trials completed and first flights scheduled for March 2025. However, these engines are still underpowered for HALE platforms, which require 900–1,000 hp turboprops to support 5-tonne airframes and heavy payloads.
Turboprop engines offer distinct advantages for MALE and HALE UAVs, including fuel efficiency, high-altitude performance, and the ability to power heavy platforms. Unlike jet engines, turboprops provide the endurance needed for prolonged ISTAR missions, critical for monitoring India’s volatile borders with China and Pakistan. The DRDO’s HALE UAV, designed to operate above 35,000 feet, will enhance situational awareness along the Line of Actual Control (LAC), while MALE platforms like Archer-NG can support precision strikes and battlefield assessment.
The DRDO’s admission of a propulsion bottleneck is a wake-up call for India’s defense ecosystem. With China deploying advanced HALE UAVs like the WZ-7 and Pakistan exploring armed drones, India cannot afford delays in its MALE and HALE programs. Turboprop propulsion is the linchpin to achieving ADE’s requirements, enabling UAVs to conduct prolonged surveillance, precision strikes, and battlefield support. By prioritizing indigenous turboprop development, India can bridge the technological gap, enhance its deterrence posture, and emerge as a leader in unmanned aerial systems.
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