HAL HF-24 Marut
|First flight||17 June 1961|
|Introduction||1 April 1967|
|Primary user||Indian Air Force|
The Hindustan Aeronautics HF-24 Marut (Sanskrit: मरुत्, for "Spirit of the Tempest") was an Indian fighter-bomber aircraft of the 1960s. It was developed by Hindustan Aircraft Limited (HAL), German aircraft designer Kurt Tank was responsible was the design of the aircraft. The Marut holds the distinction of being the first indigenously developed jet aircraft in India. On 17 June 1961, the type conducted its maiden flight; on 1 April 1967, the first production Marut was officially delivered to the IAF.
While the Marut had been envisioned as a supersonic-capable combat aircraft, it would never manage to breach the sound barrier, being limited to subsonic speeds only. This limitation was principally due to the engines used, which in turn had been limited by various political and economic factors, multiple attempts to develop improved engines or to source alternative powerplants were fruitlessly made. Criticism over the Marut's cost and lack of capability in comparison to contemporary aircraft were often made.
A total of 147 Maruts were manufactured, the majority of which were introduced to service with the Indian Air Force (IAF). While it had been initially envisioned as a capable interceptor aircraft, it was instead primarily used for ground attack missions instead. In the ground attack role, the Marut saw active combat operations during the Indo-Pakistani War of 1971, notably participating in the Battle of Longewala. By 1982, the Marut was being increasingly considered to be obsolete, and was gradually phased out during the late 1980s.
Design and development
During the 1950s, Hindustan Aircraft Limited (HAL) had developed and produced several types of trainer aircraft, such as the HAL HT-2, however elements within the firm were eager to expand into the then-new realm of supersonic fighter aircraft. Around the same point, the Indian Government were in the process of formulating a new Air Staff Requirement for a Mach 2-capable combat aircraft to equipped the Indian Air Force (IAF). However, as HAL lacked the necessary experience in both developing and manufacturing frontline combat fighters, it was clear that external guidance would be invaluable; this assistance was embodied by Kurt Tank, a German aircraft designer who had designed numerous combat aircraft of the Luftwaffe while at Focke-Wulf during the Second World War. Kurt was invited to relocate to India to establish and head the project to produce what would become India's first indigenous fighter aircraft. Upon arrival, he set about directing design work for the prospective fighter.
In 1956, HAL formally commenced design work on the supersonic fighter project. The Indian Government, led by Jawaharlal Nehru, authorised the development of the aircraft, stating that it would aid in India's development of a modern aircraft industry. The first phase of the project sought to develop a airframe that would be suitable for travelling at supersonic speeds and could effectively perform combat missions as a fighter aircraft, while the second phase sought to design and assemble a domestically produced engine capable of propelling the type. Early on, there was an explicit adherence to satisfying the IAF's requirements for a capable fighter bomber; attributes such as a twin-engine configuration and a 1.4/1.5 Mach number were quickly emphasised.
During the development phase, HAL designed and constructed a full-scale two-seat wooden glider to act as a flying demonstrator. Designated as the HAL X-241, the glider replicated the subsequent production aircraft in terms of dimensions, control configuration and aerofoil sections. The wheel-brakes, air-brakes, flaps and retractable undercarriage were all actuated using compressed gas, there was sufficient gas storage onboard to perform multiple actuations per flight. On 3 April 1959, the X-241 flew for the first time, having been launched by aero-tow behind a Douglas Dakota Mk.IV BJ 449. A total of 86 flights were conducted prior to the X-241 receiving considerable damage as the result of a landing accident in which the nose undercarriage had failed to extend.
On 24 June 1961, the first prototype Marut conducted its maiden flight. The prototype was powered by the same Bristol Siddeley Orpheus 703 turbojet engines that had powered the Folland Gnat, which was also being manufactured by HAL at point in time. On 1 April 1967, the first production aircraft was officially delivered to the IAF. While originally intended only as an interim measure during testing, HAL decided to power production models of the Marut with a pair of unreheated Orpheus 703 engines, using which the aircraft could not attain supersonic speeds. Although it had been originally conceived to operate in the vicinity of Mach 2, the Marut in fact turned out to be barely capable of reaching Mach 1 due to the lack of suitably powered engines for the airframe.
The IAF were reluctant to procure a fighter aircraft that was only marginally superior to its existing fleet of British-built Hawker Hunter fighters; however, in 1961, the Indian Government decided to procure 16 pre-production aircraft and 60 series production Maruts as well. Only 147 aircraft, including 18 two-seat trainers, were completed out of an initial target of 214 aircraft. After the Indian Government conducted its first nuclear tests at Pokhran, international pressure prevented the import of better engines, or at times, even spares for the Orpheus engines used; this situation was one of the main reasons for this aircraft's early demise. The Marut had never realised its full potential due to insufficient power. According to author Amit Gupta, the Marut "was technically obsolete by the time it was first delivered in 1964". Other authors have also commented on the Marut's relative obsolesce by the time it had reached production.
Termination and criticisms
According to aviation author Chris Smith, the Marut was "essentially a very long-drawn-out failure", he attributes the aircraft's shortcomings to multiple factors. Amongst these were the difficulties experienced in securing a suitable engine, which was principally a political issue; while arrangements were successfully established with the United Kingdom and Bristol Siddeley to domestically produce the Orpheus engine by HAL, this engine was only suitable as an interim measure as it lacked the power to enable the Marut to achieve supersonic flight. The Indian Government had refused a proposal made by Rolls-Royce to finance further development of the Orpheus, which had been specifically aimed at producing a more suitable model of the engine for the Marut.
Other envisioned alternative engines that could have potentially been sourced from the Soviet Union, Egypt and various European nations did not result in anything of substance. The Gas Turbine Research Establishment also perused their own development program to improve the Orpheus without external aid, which proceeded to the testing phase with some favourable results, but proved to be incompatible with the Marut. As the particularities of a given airframe are typically heavily dependent on the engine used, the inability to develop the Marut around a specific engine damaged its performance. Despite experimentation with various engines, the Marut was never able to achieve supersonic speeds, which was viewed as a major failure of a project which at one point had ambitions to produce a Mach 2-capable combat aircraft. The IAF had anticipated the Marut being fitted with a considerably superior engine.
The project was negatively impacted by a lack of direction and management from the Indian Ministry of Defence. A lack of coordination between the military, politicians, and industry is alleged to have been typical throughout the entirety of the program, leaving many issues down to industry alone without guidance. Specifically, the government never sanctioned the development of an engine design team, nor were there assessments of HAL's capability to reverse engineer or to apply technologies from other projects, such as the work performed for the Folland Gnat. HAL is claimed to have struggled to convince both the IAF and MoD that the design of the Marut was acceptable; much attention was given to the unacceptably high level of trail drag that the airframe produced, as well as dissatisfaction of the Marut's speed and manoeuvrability, both of which were below IAF standards upon its introduction.
Kurt himself had a major influence on the project, and accordingly of its shortcomings. While working on the Marut, Kurt has been credited with having instructed his fellow engineers well during the project, but was also noted for his rigid stance on aspects of the design. He typically had little interest in lobbying the Indian government for funding refinements to the design; elements of the IAF have been alleged to have held dismissive attitudes of Kurt and of his abilities, rarely coordinated with him on issues with the aircraft, which in turn exacerbating the type's performance issues. The level of technological transfer between German and India on the project was subject to criticism as well.
According to author Satish Kumar, the limited technological capabilities of Indian aerospace industry had created a heavy reliance on foreign technologies and imported components. Kumar also attributes HAL's willingness to undertake overly-ambitious defence projects as being partially responsible for the project's outcome and the Marut's performance. Author Amit Gupta observed that the Marut was not only heavily dependent on foreign-sourced materials, but that it was more expensive to manufacture the type in India than to have imported completed aircraft. The level of indigenous components increased over time, reportedly having reached 70 per cent by December 1973. The allocation of scarce resources to reproducing components that could have been readily acquired externally represented a high level of opportunity cost to India. According to Swarna Rajagopalan, India lacked the infrastructure and scientific base to successfully produce an effective indigenous combat aircraft at that time.
The IAF reportedly showed little confidence in indigenous fighter technology, having openly expressed its preference for the French-built Dassault Ouragan as an alternative. By the time the Marut was entering its mass production phase, the IAF had already purchased foreign-built fighters such as the Hawker Hunter and Sukhoi Su-7. Following on from the Marut, HAL proceeded to produce larger quantities of both European and Soviet combat aircraft under license, such as the SEPECAT Jaguar, Mikoyan-Gurevich MiG-21, and Mikoyan MiG-27.
The Marut was used in combat in the ground attack role, where its safety features such as manual controls whenever the hydraulic systems failed and twin engines increased survivability. According to aviation author Pushpindar Singh, the Marut had excellent low-level flying characteristics, but its maneuverability suffered due to the lack of engine power, maintenance issues also resulted in the type being problematic in service.
In 1967, a single Marut was used as a testbed for the Egyptian indigenously-developed Brandner E-300 engine. The Indian team was recalled in July 1969, while the Egypt-based Marut was abandoned.
Given the limited number of Marut units, most Marut squadrons were considerably over-strength for the duration of their lives. According to Brian de Magray, at peak strength No.10 Squadron had on charge 32 Maruts, although the squadron probably did not hold a unit-establishment of more than 16. The Marut squadrons participated in the 1971 war and none was lost in air-to-air combat, although four were lost to ground fire and two were destroyed on the ground. Three Marut pilots were awarded the Vir Chakra commendation.
Maruts constantly found themselves under heavy and concentrated fire from the ground during their low-level attack missions. On at least three occasions, Maruts regained their base after one engine had been lost to ground fire. On one of these, a Marut returned to base without escort on one engine, from about 150 miles (240 km) inside hostile territory. On another occasion, a pilot flying his Marut through debris that erupted into the air as he strafed a convoy felt a heavy blow in the rear fuselage of the aircraft, the engine damage warning lights immediately glowing and one engine cutting out. Fortunately, the Marut attained a safe and reasonable recovery speed on one engine. Consequently, the pilot had no difficulty in flying his crippled fighter back to base. Another safety factor was the automatic reversion to manual control in the event of a failure in the hydraulic flying control system, and there were several instances of Maruts being flown back from a sortie manually. The Marut had good survivability record in enemy airspace.
In the Indo-Pakistani War of 1971, some Maruts and Hawker Hunter aircraft were used to give close support to an Indian border post in the decisive Battle of Longewala, on the morning of 5 December 1971. The aerial attack was credited with destroying a large number of tanks that had been deployed by Pakistani ground forces. More than 300 combat sorties were flown by the Maruts during a two week period in the war.
One aerial kill was recorded as having been achieved by a Marut; on 7 December 1971, Squadron Leader KK Bakshi of No. 220 Squadron shot down a PAF F-86 Sabre, (reportedly flown by Flag Officer Hamid Khwaja of No. 15 Squadron of the Pakistan Air Force). Reportedly, not a single Marut sustained damage or a loss due to enemy aircraft.
By 1982, the IAF was proposing that that Marut fleet be phased out on the basis that the type was "no longer operationally viable". Supporters such as Air Commodore Jasjit Singh pointed out that the type had performed well in the 1971 combat, and had enjoyed superior safety records to other IAF aircraft such as the Gnat. Some aircraft had less than 100 recorded flight hours at the point by which the retirement of the Marut was being mooted.
- HAL X-241
- A full scale research glider replicating the proposed production aircraft, with identical dimensions, control configuration and aerofoil sections.
- Marut Mk.1
- Single-seat ground-attack fighter.
- Marut Mk.1A
- The third pre-production aircraft fitted with an afterburning Bristol Siddeley Orpheus 703 with 18% boost at 5,720 lbf (25.44 kN) thrust.
- Marut Mk.1 BX
- A single Mk.1 converted as a flying test-bed for the Brandner E-300 turbojet engine.
- Marut Mk.1T
- Two-seat training version.
- Marut Mk.1R
- Two HF-24s fitted with two afterburning Bristol Siddeley Orpheus 703s with 18% boost at 5,720 lbf (25.44 kN) thrust.
- Marut Mk.2
- A projected Rolls-Royce Turbomeca Adour powered derivative.
- Indian Air Force
Data from: There are several surviving Maruts open to public inspection:
- Visvesvaraya Industrial and Technological Museum, Bangalore.
- HAL museum! Bangalore
- Kamla Nehru Park, Pune.
- Nehru Science Centre Mumbai.
- Periyar Science and Technology Centre, Chennai
- ASTE (Aircraft & Systems Testing Establishment), Bangalore
- Air Force Academy, Dundigul
- Deutsches Museum Flugwerft Schleissheim
- Indian Air Force Museum, Palam
- Museum für Luftfahrt und Technik Wernigerode, Germany
Specifications (Marut Mk.1)
Data from Jane's All The World's Aircraft 1976-77 
- Crew: 1
- Length: 15.87 m (52 ft 0¾ in)
- Wingspan: 9.00 m (29 ft 6¼ in)
- Height: 3.60 m (11 ft 9¾ in)
- Wing area: 28.0 m² (301 ft²)
- Empty weight: 6,195 kg (13,658 lb)
- Max. takeoff weight: 10,908 kg (24,048 lb)
- Powerplant: 2 × Bristol Siddeley Orpheus Mk 703 turbojet, 21.6 kN (4,850 lbf) each
- Maximum speed: 1,112 km/h (600 kn, 691 mph) at sea level
- Stall speed: 248 km/h (133 knots, 154 mph) (flaps and landing gear down)
- Combat radius: 396 km  (214 nmi, 246 mi)
- Service ceiling: 13,750 m (45,100 ft)
- Guns: 4× 30 mm (1.18 in) ADEN cannon with 120 rpg
- Rockets: Retractable Matra pack of 50× 2.68 in (68 mm) rockets
- Bombs: Up to 4,000 lb (1,800 kg) on four wing pylons
|Video overview of the Marut|
|News report on the 50th anniversary of the Marut's first flight|
|Contemporary silent footage of the Marut at an air show, including an aerial display|
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- Related lists
- Donald 1997, p. 523.
- Satish 2015, p. 480.
- Gupta 1997, p. 34.
- Smith 1994, p. 160.
- Singh, Sushant. "Tejas is not India's first indigenous fighter, that would be the HF-24 Marut." Times of India, 1 July 2016.
- Rajagopalan 2014, p. 116.
- Bhargava, Kapil, Gp.Capt. (retd.). "The HF-24 Marut's Glider Prototype". bharat-rakshak.com. Retrieved 10 June 2014.
- "HF-24 Marut". Federation of American Scientists.
- Arnett 1997, pp. 120-121.
- Smith 1994, pp. 160-162.
- Smith 1994, pp. 160-161.
- Smith 1994, p. 161.
- Arnett 1997, p. 120.
- Thomas 2014, p. 260.
- Smith 1994, p. 162.
- Smith 1994, pp. 160, 162.
- Arnett 1997, pp. 119-120.
- Rajagopalan 2014, p. 138.
- Taylor 1969, p. 671.
- "Marut", India, Global Security.
- "Marut", IAF, Bharat Rakshak.
- Nordeen 2002, p. 81.
- "Polly Marut", IAF, Bharat Rakshak
- CHATTERJEE, K. "HINDUSTAN FIGHTER HF-24 MARUT PART I: BUILDING INDIA'S JET FIGHTER". www.bharat-rakshak.com. Retrieved 10 June 2014.
- Bharat-Rakshak.com, HINDUSTAN FIGHTER HF-24 MARUT, accessed July 2009
- "Maruts on Display – Sublime to the Ridiculous". marutfans.wordpress.com. Retrieved 10 June 2014.
- Taylor 1976, pp. 79—80.
- Arnett, Eric H. Military Capacity and the Risk of War: China, India, Pakistan, and Iran. Oxford University Press, 1997. ISBN 0-19829-281-3.
- "Maruta: India's Hindustan HF-24 Joins the IAF". Flight International, 2 July 1964, Vol. 86, No. 2886. pp. 16–17.
- Donald, David (editor). The Encyclopedia of World Aircraft. London:Aerospace, 1997. ISBN 1-85605-375-X.
- Gupta, Amit. Building an Arsenal: The Evolution of Regional Power Force Structures. Greenwood Publishing Group, 1997. ISBN 0-27595-787-X.
- Taylor, John W. R. Jane's All The World's Aircraft 1969–70. London:Jane's Yearbooks, 1969.
- Kumar, Satish. India's National Security: Annual Review 2013. Routledge, 2015. ISBN 1-31732-461-7.
- Nordeen, Lon O. Air warfare in the missile age. Smithsonian Institution Press, 2002. ISBN 0-198-29168-X.
- Rajagopalan, Swarna. Security and South Asia: Ideas, Institutions and Initiatives. Routledge, 2014. ISBN 1-31780-948-3.
- Smith, Chris. India's Ad Hoc Arsenal: Direction Or Drift in Defence Policy? Oxford University Press, 1994. ISBN 0-19829-168-X.
- Taylor, John W.R. (editor). Jane's All The World's Aircraft 1976–77. London:Jane's Yearbooks, 1976, ISBN 0-354-00538-3.
- Thomas, Raju G.C. Indian Security Policy. Princeton University Press, 2014. ISBN 1-40085-819-4.
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