HAL HF-24 Marut

The HAL HF-24 Marut ("Spirit of the Tempest") was an Indian jet fighter aircraft developed and manufactured by Hindustan Aeronautics Limited (HAL) during the 1960s and early 70s. The Marut was designed by the German aeronautical engineer Kurt Tank, with the Project Engineer being George William Benjamin. The aircraft was the first Indian-developed jet fighter. 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 interceptor aircraft, it would never manage to exceed Mach 1. 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 fruitless.

The Marut's cost and lack of capability in comparison to contemporary aircraft were often criticised. Nevertheless, the Marut performed relatively well in combat, primarily as a fighter-bomber in the ground attack role. Most notably participating in the Battle of Longewala during the Indo-Pakistani war of 1971.

A total of 147 Maruts were manufactured, with the Indian Air Force (IAF) being the sole operator. By 1982, the Marut was becoming increasingly obsolescent, and was gradually phased out during the late 1980s.

The aircraft was named "Marut", after the storm gods of the Rig Veda, symbolising speed and power. This was part of a broader IAF tradition of Sanskrit-based naming for indigenously developed platforms.

Design and development

thumb|A preserved HF-24 Marut in Bengaluru

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 time, the Indian government was in the process of formulating a new Air Staff Requirement for a Mach 2-capable combat aircraft to equip 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.

In 1956, HAL formally began design work on the supersonic fighter project. The first phase of the project sought to develop an airframe suitable for travelling at supersonic speeds, and able to effectively perform combat missions as a fighter aircraft, while the second phase sought to domestically design and produce an engine capable of propelling the aircraft. On 3 April 1959, the X-241 flew for the first time, after being towed into the air by a Douglas Dakota Mk.IV (BJ 449). A total of 86 flights were conducted prior to the X-241 sustaining considerable damage in a landing incident, when the nose undercarriage failed to extend. Before suitable, afterburning engines had been obtained, the Indian Government decided to order 16 pre-production and 60 production Maruts,

On 1 April 1967, the first production Marut was officially accepted by the IAF. Only 147 aircraft, including 18 two-seat trainers, were completed out of a planned 214. Among 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 for HAL to domestically produce the Orpheus, it was only suitable as an interim measure as it lacked the power to enable the Marut to achieve supersonic speed. The Indian Government refused a proposal made by Rolls-Royce to finance further development of the Orpheus, which had been specifically aimed at producing a more suitable engine for the Marut. Despite experimentation with various engines, the Marut was never able to achieve supersonic speeds, which was viewed as a major failure.

The project was negatively affected by a lack of direction and management from the Indian Ministry of Defence. and he typically had little interest in lobbying the Indian government for funding to refine the design. In addition, however, elements of the IAF have been alleged to have held dismissive attitudes toward Tank and of his abilities, rarely coordinated with him on issues with the aircraft, which in turn exacerbated the type's performance issues. The level of technological transfer between Germany and India on the project was subject to criticism as well.

Limitations within the Indian aerospace industry, which lacked the infrastructure and scientific base to successfully produce an effective indigenous combat aircraft at that time, 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.

Operational history

thumb|A preserved Marut on static display. This aircraft had participated in the [[Battle of Longewala.]]

The Marut was used in combat in a 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. The Indian team was recalled in July 1969, while the Egypt-based Marut was abandoned.

Maruts constantly found themselves under heavy and concentrated fire from the ground during their low-level attack missions. On at least three occasions, Maruts managed to return to their base after one engine had been lost to ground fire. On one of these occasions, a Marut returned to base without escort on one engine, from about 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 to the rear fuselage of the aircraft, the engine damage warning lights immediately illuminated, and one engine cut 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 flight control system, and there were several instances of Maruts being flown back from a sortie under manual control. All in all, the Marut had a 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.

thumb|right|HAL HF-24 D-1205 preserved at the Indian Air Force Museum, New Delhi.

By 1982, the IAF was proposing that the Marut fleet be phased out on the basis that the type was "no longer operationally viable".

;Marut Mk.1 BX:A single Mk.1 converted as a flying test-bed for the Brandner E-300 turbojet engine.

Surviving aircraft

thumb|HF-24 Marut preserved at the [[Deutsches Museum Flugwerft Schleissheim near Munich]]

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 now on display at Museum für Luftfahrt und Technik Wernigerode
Indian Air Force Museum, Palam
Sainik School, Kazhakootam, Kerala

Specifications (Marut Mk.1)

thumb|Midsection of Marut. Note the two-seat cockpit and the placement of the air intakes

thumb|Closeup of a section of the underside of a Marut