Kurt Tank – The legendary test pilot and aircraft designer

 And the Marut HF 24 project at Bangalore

Prof. Dr. Dipl.-Ing. Kurt Waldemar Tank was not only a brilliant German engineer and designer of many successful aircraft that flew in the Second World War but was also a competent test pilot. Responsible for the designs of the Fw 190 fighter, the Ta 152 fighter interceptor, and the Fw 200 long-distance Condor, Kurt led the design department at Focke-Wulf which manufactured these aircraft. While the Fw 190 fighter (over 20,000 were produced) was considered one of the finest flying fighters of its time, Tank also pioneered nonstop transatlantic air travel with his Condor aircraft. After the war, he moved to Argentina, building their first fighter jet, the Pulqui II.

Following the fall of Peron, Tank took up an offer to lead a design team at the fledgling Hindustan Aeronautics Ltd (HAL) Bangalore, working on an ambitious project developing a Mach 2 fighter – the Marut HF-24. Kurt Tank, who focused on trying to get things going under incredibly difficult circumstances, and supported by a primitive industrial infrastructure, maintained a low profile and talked little. Perhaps he had his demons to face. This is his story.

Though there is plenty of material out there on the German planes he helped design, and quite a bit on the Marut HF 24, much of the HF-24 information out there comes from one or two templates which are somewhat incomplete and at times erroneous, with most of them disregarding the geopolitical pressures faced by not only the developers at HAL but also the politicians at Delhi, walking a tight rope in a cold war era, pressured by the Russians on one side and a combination of America, France and Britain on the other.

The initial part of Tank’s life, until the conclusion of WW-II is well documented, so I will quickly gloss over them. Born in Bromberg, Germany in Feb 1898 to Willi and Anna, Tank was keen to join the air services, but his father, an army grenadier forced him to join the cavalry, and Tank dropped out of school and volunteered for the army aged 17, did well, earning several medals, eventually de-mobbing as a Captain. Picking up his education Tank graduated in Electrical Engineering from the Technische Hochschule Berlin, in 1923 (he was a regular listener to Einstein’s lectures at Berlin on Relativity!), meanwhile qualifying as a pilot as well (flying solo after just three tutored flights) and formed a gliding club. It was his professor Moritz Weber who suggested he look at aircraft design as a future career when he saw Tank was considering Siemens. With his professor’s recommendation, he soon joined the design team designing flying boats at Rohrbach Metall-Flugzeugbau, and later a stint at supplying planes to Turkey and meeting Ataturk. This was followed by a troubling year with Willi Messerschmitt as director of the Projects Department at Bayerische Flugzeugwerke, eventually moving on to work for a small aircraft manufacturer, Focke-Wulf at Bremen, as the manager of tests and design in 1931. Tank’s involvement in engineering and aircraft designs led them to fame, and he rose to become its technical director. In Sept 1924, he got married to Charlotte Teufel, his first wife.

It was at FW that he designed the long-distance Fw-200 Condor and the feared Fw-190 fighter. Most importantly, he was not just a designer, but also an able test pilot and eventually rose to become its managing director. As a test pilot, he did have his share of mishaps, but it was his flying skill that added to his drawing board knowledge of designing planes. Tank’s Focke-Wulf Fw 190, according to Robert Grinsell was “considered by many aviation experts and enthusiasts to be the most beautifully proportioned and aerodynamically designed aircraft of World War II”. Interestingly, he was always known as Professor Kurt Tank (per some accounts - awarded by the Braunschweig Technical School), though he became a teacher only much later, while in India.

Fw 190A-3
Though he was a Nazi pilot and worked for Nazi-controlled factories employing Jewish slaves, it is apparent from various biographies that he was not too involved with or interested in the politics of his country (Nevertheless, Goering had appointed him as one of his military economy leaders, sworn to be faithful to the Nazi regime) but was driven by aviation and engineering. There are interesting accounts of Tank’s arguments about the production and design of new fighter bombers with Goering and how Tank stood his ground. We also see that he had four meetings with Hitler. Tank became quite famous by now and was allowed to use the Ta monogram for his planes. The last of his designs, the Ta 183 was the forerunner to the Russian Mig-15, for the Russians obtained all the aircraft design and research files following the war. The Russians also obtained two prototypes, which they used to jump-start their MIG project. Still, Tank had also secreted the blueprints of the Ta 183 swept-wing fighter plane, which was in his possession.

After the war ended, and the British control of Focke-Wulf, interrogations were completed, Tank, like many other German engineers were looking out for work and living the life of a refugee, in 1946. During this period, Tank lived in an ancient castle situated in the Weser hills and had to forage for food and subsistence! While there is a brief mention of Tank consulting for General Electric on aero engines much later in life circa 1952, there is nothing on record about any discussions with the Americans, immediately after the war. However, the Soviets, the British, China, France, Sweden, Mexico, and Brazil all investigated the possibility of Tank emigrating to help develop their aircraft industries. Tank commenced further discussions with the British for a job with Handley Page, which never reached fruition. The discussions with China were interesting, and they almost reached a contract stage, but Mao Tse-Tung’s revolution and nationalist China’s decline put paid to that.

Fw 200C 
Pushed by the Soviets, Tank slipped out to Berlin and was interviewed by the Russians who proposed that he move to the Eastern zone, and work for them, but the eventual Russian offer was too vague. A trip to Russia to meet Stalin did not work out when Tank caught the flu and was sent back home. Tank had realized that he would never be a free man in Russia, and his fears were confirmed when a few years later the go between Col Tokaev defected to Britain. Another report mentions that Tank took 10,000 Marks, after agreeing to go to Russia with 8-10 followers, but that he failed to appear. Tank continued work on the Ta 183 and a futuristic long-distance plane, the Ta 500.

A rumor that he would be tried under the war trials and a physical summons to travel to Britain late in 1947, got Tank searching for an escape route to where hundreds of thousands of Germans, mostly Nazis had fled, namely Juan Peron’s Argentina. Their exit route was through Denmark, which had not closed its borders. The go-between, an Argentine SS officer Fultner was involved in the secreting out of Kurt Tank to Argentina. SS officer Karl Nicolussi-Leck, the escape agent of the chimeral ODESSA organization, was perhaps the person who delivered Kurt Tank and later his engineering team to Fultner who then took over and spirited them across to Argentine. Tank had a hair-raising transit through Britain and managed the escape to the Southern Hemisphere with his papers and the microfilms bulging in his pocket, under a false Argentinian passport, bearing the name Pedro Matties.

Argentina was very rich at this point, the 7th largest economy, and had the funds to get the people they wanted and the money to further Juan Peron’s dreams. Several of Tank’s former colleagues, around 62 of them, joined him in Cordoba and together they created something like a Focke-Wulf Lite unit.  Soon after he arrived in Argentina, Tank’s wife Charlotte passed away and Tank later got married to a girl 30 years his junior, a girl he knew from her childhood, Sigrid Güldennage. Meanwhile, his two daughters and a son from his first wife were growing up.

These engineers and their families lived on the mountain slopes near Cordoba. The intent was to use the Ta183 designs and make a new fighter for the Argentine Air Force. They took over the Pulqui project which until then had been managed not too well by the French Nazi designer Emile Dewoitine. The Institutio Aerotechnico was formed and by 1950, the advanced IAe-33 Pulqui II had been modelled using the basic TA 183 airframe, and a glider version had been tested. Interestingly it had no hydraulic controls. In 1951, a test flight was conducted by Tank in front of Peron. But it all went south, thereafter.

One of the reasons for Tank’s fall from Peron’s grace, was the failure of the man behind the ill-fated nuclear fusion project, the infamous Ronald Richter, whom Tank had recommended to Peron. Tank had been fascinated by Richter’s ideas, especially the one concerning a lightweight fusion engine for a futuristic aircraft that Tank had envisioned. But Richter turned out to be a dud (the word is divided, some call him a crackpot, some even say his work on nuclear fusion, the Huemul project was sabotaged), following which Tank also fell from grace. It is also said that the Pulqui II touted to become the foremost fighter jet in the world, turned out to be a pipe dream, with its airframe weight and many aerodynamic problems due to manufacturing difficulties (the frames had to be hand fabricated). Three prototypes were constructed by 1953 and finally, the fourth one passed tests, but at a much-reduced speed, and with no reliable large-scale manufacturing program, export buyers backed out.


Meanwhile, the Argentine economy had nosedived and in 1955, Tank’s contract expired. Rumors swirled around of Tank’s request to double his salary which infuriated Peron, of his being arrested for possessing a forged passport (strange since he used to travel to Europe with his German passport). In a coup that followed, Peron was kicked out of Argentina and Kurt Tank was soon in limbo. Strangely the only Pulqui II ever manufactured was used against Peron, in its sole engagement, during the coup!! The new regime could only offer basic jobs and previous contracts were not honored. According to the Kurt Tank biographer – Heinz Conradis, Tank returned to Germany in 1954, faced with a difficult future with no aircraft industry in post-war Germany to work for, and still in contract with Argentina.

That was when Kurt Tank was approached by the Indian government through Dr. Taupisch, the German trade attaché in Delhi. Tank met Mahavir Tyagi the defense minister (1953-57) in Bonn, at the behest of Air Marshal S Mukerji, and was later flown around various facilities in India including the HAL. While most of his team went to the American firm's Republic Aviation and Glen Martin, Tank evaluated the Indian offer and negotiated at length, after which he met Krause, the new minister for Aviation in Argentina, and obtained a release.

As always, he insisted on his team to accompany him and so in Feb 1956, Tank arrived in India with a smaller team of eighteen German engineers and technicians, which number later dwindled to thirteen (most of the others went back to Germany, remained in Argentina, or moved to the USA). The HAL team which worked on the new aircraft was led by the Project manager Ludwig Mittelhuber, three Indian senior design engineers, and about 22 other Indian engineers with some design experience. Tank was paid a princely sum of Rs 6,000 per month (in today’s terms this is many lakhs of Rs in buying power) but faced a tall demand of designing a Mach 2 fighter with a 500-mile range and flying at 60,000 feet, using an organization which had thus far built simpler trainer planes from kits and serviced US and British WWII planes. It is not clear if he had program management responsibility, i.e., production, supply chain, etc. Perhaps not, but people saw him as the head and tail of the project.

Sadly, the complete details of Tank’s stay in Bangalore, especially personal details, are not available anywhere, only the HF-24 development work at HAL is known to some extent. All we know are a few details of his meetings with Nehru and VK Krishna Menon, and the fact that he lived in a nice house with a terrace, nestling among the scarlet blossoms of the cassias. It had a covered gallery with a balustrade, leading to a timber outhouse which was perhaps his office, with 49 pillars supporting a roof! Now I cannot fathom where in Bangalore such a house existed, perhaps somewhere in the Indira Nagar area, and anybody who can dispel this mystery may comment. It is also not clear if Sigrid and Tank’s four children (His fourth child Diana must have been 4-5 years old then) stayed in Bangalore or studied there, for he lived there for close to a decade.

Marut HF 24

To cut the long story short, he and his team, which had swelled to some 100 plus Indian engineers, designed, and built the HF-24 Marut, a sleek and sharp high-nosed, twin-engine jet, perhaps the aerodynamically cleanest fighter airframe of its time. One of the first glider prototype test pilots, incidentally, was a Malayali - Oyitti Manakkadan Kunhiraman, flying together with Kapil Bhargava. The Marut was intended to be capable of Mach 2(~ 1,500 miles per hour), but the British Bristol Olympus afterburning engines around which it was designed never materialized, so other engines had to be tried.

The engine fiasco resulted from the need for a Bristol BOr.12 SR Orpheus after-burning turbojet that could produce 8,150 pounds of thrust. Unfortunately, India did not have or were unwilling (and lots of geopolitics) to invest 13 million pounds for Bristol to develop the engine after NATO dropped its need, so the HAL team spent years shopping for an alternative in the Soviet Union, Europe, and the United States, only for shifting political winds to nix the deal at every turn. In the end, HAL was forced to make do with non-afterburning Orpheus 703 turbojets used by the Folland Gnat, which generated just 4,850 pounds of thrust. As a result, what was intended to be a Mach 2 fighter could barely attain Mach 1, that too at higher altitudes.

The first powered prototype of the HF-24 powered by two Orpheus 703 engines made its successful flight in June 1961 and the second prototype in October 1962. An initial batch of these aircraft was handed over to the Indian Air Force in 1964. Only 147 HF-24s were procured, (including eighteen two-seat trainers), all inducted by 1968 and these formed the IAF No. 10 Flying Dagger, No. 31 Lions, and No. 220 Desert Tigers squadrons. By then, it had cost more to produce the Marut in India with very many imported parts, than it did to fully import more advanced & capable fighters from other countries.

Various other engines were then looked at, the Russian RD-9F and VK-7, and afterburning Orpheus, the Egyptian Brandner E-300, the RR RB.153, the P&W J52, and the GE1/JO-1 but they did not quite work out. There is some talk of the DRDO/GTRE attempts in 1966 for a reheat system to make an HF 24 Mk II, but Tank does not seem to have supported the idea for design reasons. Later audit reports on the project mention large cost overruns, tooling issues, and lack of a production engineering department at HAL, that the new reheat version performed worse than the original, and that the base drag was considerable. Eventually, IAF did not support the reheat system idea, and HF 24 manufacture ended in 1977.

Wagner’s book on Tank, edited and verified by Tank, explains that Menon had to intervene to get the RD-9F engines from Russia and the HAL team found the bench tests were quite satisfactory. However, the Russians suddenly became disinterested in the project and did not want to proceed further.  Tank realized that the HF24 + RD-9F combination would perform better than the MIG21 and would therefore jeopardize the larger ongoing MIG21 deal between India and Russia. Russia then informed the Indian team that the RD-9F would have a service life of just 50 hours compared to international standards between 500-2000 hours. All said, India finally decided not to buy these Russian engines. America stepped in and offered the RB 153 engines, but on condition that India abandon the MIG 21 deal, which was not possible since the MIG contract had been signed. These aspects never found their way into any media reports thus far!!

The Egyptian collaboration - Nasser’s aircraft program to develop the HA 300 had started with Messerschmitt’s guidance. A new engine was designed by the Germans using a French Mirage model in 1961 and this was the Brandner E 300, and still a prototype, but then the HA 300 airframe was not ready. Tank knew of all this after his visit to Helwan in 1963. Remember that these were the Nehru-Nasser-Tito days, and well, fortuitously India had a perfect airframe but no engine. So, a plan was floated to gift an HF 24 to Egypt and test it with an E 300 engine in flight and if it worked, both the involved countries would buy the missing parts from one another. A test flight was conducted in 1966, with Tank present. While Indian media stated that the Egyptians only needed the HF 24 airframe for testing, Wagner writes that the Egyptians informed India that they could not supply any E 300 engines. Whether it was because of Egypt’s loss in the 6-day war or due to the political turbulence in Egypt, is not clear.

Grp Captain Kapil Bhargava who was Marut’s chief test pilot since 1957, opines (Marut fans blog) that Tank was quite rigid and a bit old-fashioned when it came to the Marut design - While Prof. KW Tank was a very good designer, he did not know much about production technology to minimize manufacturing time, costs and time or to ensure maintainability. Kurt Tank belonged to the old school, suspicious of new technology such as powered controls. Rather reluctantly he decided to power the controls but only with a single hydraulic system, including the services such as wheel brakes, undercarriage, flaps, and airbrakes. Tank’s well-advertised boast was that his aircraft would be so strong that if the wing hit a tree, the tree would get sliced off with the aircraft capable of flying back home. There is also a funny mention of how the cockpit was designed for a much larger man. Bhargava found the seat too big for his small bottom (Tank was a large man) and the controls too far, and thus a redesign was needed for the Indian. There are also interesting mentions of the Tank’s chat with Nehru and the test flight with Krishna Menon as a witness.

Perhaps age had caught up, but it is quite clear that after the engine issues, the HAL production team had many changes to grapple with and difficulties with large-scale production planning, all of which were not in Tank’s hands. Perhaps it was the bureaucracy, squabbles with the IAF, and the lack of advanced facilities. However, all said, many disagree that the HF 24 was a failure, for this aircraft did enter a production stage, served in the IAF for over two decades, and proved itself in a war. Moreover, its accident rate was very low—just one accident and around three aircraft lost in combat. From a lofty performance goal, which it tried to meet, and a cost overrun, the HF 24 was indeed a failure, but that was all because it could not get the engine it was designed for, and the nonexistent large-scale manufacturing and production engineering facilities, which were not factored for during budgeting.

As the MIG 21 local assembly project was finding difficulties getting off the ground, Tank completed his HF 24 project with the OR 703 engines, though not meeting the original lofty Mach 2 speed objective, and was ready with deliveries to the IAF. He finished his contract with the Indian government in April 1967 and decided to hang up his boots, for good.

During the 1971 India-Pakistan war, the Marut acquired a sterling record for rugged reliability as a low-altitude fighter bomber. This was one of the planes that saved the day in the 1971 Longewala battle – remember the famous scene pictured in the film Border, where Jackie Shroff and his planes finally take off at dawn and blow away the bogged-down Pakistani tank unit with a small Indian contingent led by Brigadier Kuldip Singh Chandpuri desperately trying to hold on? If the Pakistanis broke through, Jaisalmer would fall. The planes could not operate during that sleepless night, since they were not equipped for night fighting, but they took off at the break of dawn, with the Maruts and Hunters decimating the Pakistani tank unit. As a Marut pilot recorded - the Marut remained in the thick of the action throughout the thirteen-day war, strafing airfields, bombing ammunition dumps, hitting tanks and artillery on the frontlines, flying over two hundred sorties, and suffering three losses to ground fire. Nonetheless, the HF-24s boasted a high serviceability rate and proved quite tough, with several of the jets managing to return to base on just one engine after the other was shot up.

Back to Kurt Tank - there is this mention that he taught initially at the Madras Institute of Technology MIT at Madras.  After Tank arrived in India, funding approval by the Indian government proved to be very slow, so Tank was parked at the Madras Institute of Technology for a while, moving to HAL only later in 1956. There is little detail of his time at MIT, but we can see a mention by the late Indian President APJ Abdul Kalam in his book that he had been Prof Kurt Tank’s student. Kurt Tank worked under Austrian Prof Walter Repenthein who headed the aeronautical department at MIT. Who knows if Tank taught Kalam Bernoulli’s principle, the foundation for all aeronautical engineers and aviators! Kalam as you all know grew up to become the nation’s foremost rocket and missile engineer, and eventually the head of the armed forces and the President of India. I am sure Kurt Tank would have been proud to hear that, but it all happened after Tank’s demise!

He was indeed an interesting man with clear ideas- for example, he believed that one could if required, communicate with extra-terrestrials through geometry, simply because, to design a spaceship, one had to know the Pythagoras theorem! According to a senior airman, he had this dictum - "A plane should not be a racehorse, that can turn in a wonderful performance on the track only at certain times and in just the right conditions: a plane should be a cavalry horse, that can run and fight in all conditions, good or bad, and that does not need to be pampered or spoilt – a plane should be like a Dienstpferd, a cavalry horse." This was the Tank Dienstpferd design policy.

Tank spent the rest of his life in Munich and briefly consulted for MBB. He did not forget India, In 1967, he tried to convince the West German government to manufacture the HF 24 under license in Germany, but after Nehru died in 1964, there were no takers in India. He suggested in 1972 that HAL cooperate with MBB when a new spec for the ASA design came up, that the new HF 73 design could potentially use the RB.199 34R engine, and beat the MIG 25 performance, but the project was dropped again due to non-availability of the engine. Kurt Tank fell seriously ill and passed away in Munich, on June 5, 1983, aged 85. Air Marshal LM Kartre visited Munich to pay his condolences to Tank’s bereaved wife Sigrid and upon her request, donated an HF 24 to the Deutsches Museum, where it is displayed proudly, to this day.

The MIG 21, French Mirage, the MIG 29, The British Jaguar, etc. were inducted afterwards, so also the locally built Tejas (with US-GE engines), and India is now talking about buying even more advanced planes such as the Rafale. As usual, the world spends billions on deterrence, be it traditional armaments or nuclear technology, with the increase in threat perceptions and the resulting cost of defense and deterrence.

Strange, that the modern world continues to move ahead on a road built upon mistrust. If we went ahead however on a road built upon trust, all this money could have been used for better purposes, but that everybody is going to tell me, is impractical and utopian thinking.

Design for Flight: The Kurt Tank Story - Heinz Conradis
Designer-Pilot Kurt Tank - by Stephan Wilkinson (history-net)
Self-reliance and Self-sufficiency: Experience of the Indian aircraft industry, Thesis 1983 - Ravindra Tomar
A man with a wide horizon Nicolussi Leck - Gerald Steinacher (A Nazi Past: Recasting German Identity in Postwar Europe - edited by David A. Messenger, Katrin Paehler)
Why India is not a great power yet – Bharat Karnad
Operation Damocles – Roger Howard
Hunting Evil – Guy Walters
Kurt Tank: Konstrukteur und Testpilot bei Focke - Wulf– Wagner W, English, Trans 1998: Don Cox
Conversations With: Reimar Horten - David Myhra
A Technological History of Cold-War India, 1947–⁠1969 - William A.T. Logan


Note: I admire Kurt Tank as an engineer, also due to my interest in flight, and Tank’s work for India. This does not mean I condone his previous relations with the Nazi regime or the Fw use of slave labor, I abhor those actions, emphatically.  


HAPPY ONAM to all readers