Wednesday, 19 May 2021

From Nu.D.40 to Bayraktar Akıncı: Demirağ’s Legacy

By Stijn Mitzer and Joost Oliemans
Benden bu millet için bir șey istiyorsanız, en mükemmelini istemelisiniz. Madem ki bir millet tayyaresiz yaşayamaz, öyleyse bu yaşama vasıtasını başkalarının lütfundan beklememeliyiz. Ben bu uçakların fabrikasını yapmaya talibim. - If you want something from me for this nation, you should ask for the most splendid. Seeing that a nation cannot live without a plane, we shouldn't expect this means of living from the grace of others. I aspire to build the factory for these planes. (By Nuri Demirağ)
Turkey's ascension as a global aviation giant has in modern history been unrivalled in the scale, scope and speed of its achievements. This accomplishment is in no small part due to the country's determined endeavours towards attaining near self-sufficiency in the defence sector, in turn becoming less dependent on foreign suppliers and countries that have sanctioned Turkey on more than one occasion. Although the fruits of this policy are already in active service in most sections of the Turkish Armed Forces, arguably the most ambitious attempts at achieving self-sufficiency are the development of the Hürjet advanced jet trainer and the TF-X stealth air superiority fighter, both of which are slated to make their first test flights this decade.
Yet Turkey's efforts at designing and producing combat aircraft are not limited to manned systems alone. There are currently at least two active programmes for the development of unmanned combat aircraft in Turkey. The first of these is set to enter service later this year: The Bayraktar Akıncı developed by Baykar Savunma. The Akıncı brings novel capabilities to the field, including the ability to launch cruise missiles and beyond-visual-range air-to-air missiles (BVRAAMs), making the Akıncı the first unmanned platform in the world that can do so. The Akıncı drastically expands the scope of Turkey's drone warfare capabilities to now also target enemy aircraft, UAVs and helicopters at ranges as far as 100 kilometres away.
As the production of the new Akıncı is eagerly pushed ahead, one more unmanned combat aircraft type is currently under development: the MİUS (Muharip İnsansız Uçak Sistemi) project, again by Baykar Savunma. Slated to make its first test flight by 2023, this supersonic combat drone is designed to carry out precision bombings, close air support (CAS) missions and suppression of enemy air defences (SEAD) in contested airspace. Although currently still confined to the drawing boards, the MİUS project shows that the Turkish defence industry is thriving, with new designs being introduced rapidly thanks to an impressive ability to overcome challenges with indigenous solutions, putting Turkey at the front of innovation in multiple defence categories.

Unbeknownst to many however is the fact that neither the TF-X nor the unmanned systems currently in development are Turkey's first attempts at designing a homegrown combat aircraft. Its first try at realising such an aircraft can actually be traced back to the 1930s, when Turkish aircraft manufacturer Nuri Demirağ (1886-1957) set out to design a twin-engined single-seat fighter aircraft that was as revolutionary as it was unconventional. Unfortunately, the efforts of Nuri Demirağ have received little attention outside of Turkey, and even in the country itself his novel design was until recently completely unknown.

But before going into detail on the efforts of Nuri Demirağ and the Nu.D.40 itself, it is insightful to give a brief history of Turkey's aviation industry prior to the outbreak of the Second World War. While most nations in Europe had some form of aircraft industry during the 1930s, Turkey's initial attempt at establishing an aviation industry already occurred in February 1925, when it founded the Turkish Aeronautical Association (Türk Hava Kurumu - THK) in anticipation of the rapidly expanding role of air power in conflicts and (civilian) transport. [1] Seeking to team up with a foreign partner to provide initial support and expertise, an agreement was signed with the German Junkers company, and in August 1925 Tayyare and Motor Türk Anonim Şirketi (TOMTAŞ) was established. [1]

The agreement with Junkers called for the establishment of a factory in Eskişehir for the production and overhaul of smaller aircraft and a more expansive facility in Kayseri to produce and maintain larger aircraft. Although at first mainly a German-run affair, German involvement was to slowly wind down and be replaced by indigenously manufactured parts and workers, ultimately becoming a truly indigenous effort. [1] The first planes produced at TOMTAŞ were the Junkers A 20 reconnaissance aircraft and Junkers F-13 transport aircraft, of which some 30 and three examples were produced respectively. [1] TOMTAŞ was intended to ultimately produce some 250 aircraft per year, showing that its establishment was more than just a token effort at setting up an indigenous aircraft industry.
But already soon after its establishment, problems started to emerge that would eventually lead to the downfall of the entire project, mainly brought on by financial difficulties on the side of Junkers. [1] After the German government withdrew its support for Junkers, which already was on the verge of bankruptcy, the company officially terminated the partnership with Turkey in June 1928, followed by the closure of TOMTAŞ several months later. The factory continued its maintenance and repair activities after its transfer to the Turkish Ministry of Defence before being renamed the Kayseri Aircraft Factory in 1931, continuing to assemble aircraft until 1942. [2] Today, the former grounds of TOMTAŞ in Kayseri are home to the main tactical transport air base of the Turkish Air Force (Erkilet Air Base), housing A400M, C-130 and CN-235 transport aircraft.

License production of Polish PZL P.24s at the Kayseri Aircraft Factory in the 1930s

With the role of the Turkish indigenous aircraft industry now limited to assembling aircraft rather than the original goal of one day designing and producing them, Turkish industrialist Nuri Demirağ began to float around the idea of reinitiating Turkey's efforts in this field. Demirağ was certainly no stranger to innovation and major construction projects, his companies having laid some 1.250 kilometres of railway throughout Turkey during the 1920s. [3] In honour of his contribution to the development of the Turkish railways, President Mustafa Kemal Atatürk awarded him the surname Demirağ (meaning iron web) in 1934. Demirağ's next project would be of an even more ambitious scale, and with his own funds he established an aircraft factory in the Beşiktaş district of Istanbul in 1936.
Already in the same year, the first aircraft designed by Demirağ and his team of engineers began to take shape. The Nu.D.36 was a two-seater basic training aircraft, of which 24 examples were eventually produced. [3] It was soon followed by a more ambitious design in the form of the Nu.D.38 twin-engined passenger aircraft, prototype construction of which lasted well into World War II, followed by its first test flight in 1944. To better facilitate growth and flying operations, Demirağ purchased a plot of land in the Yeşilköy area of Istanbul for the establishment of an airfield and flight school (which trained some 290 pilots until 1943) on what is nowadays the location of Istanbul Atatürk Airport. [3] His broad-ranging ambitions and extensive efforts across the field should be sufficient to prove Demirağ's goals were not limited to designing and producing aircraft alone, but also aimed to kickstart a process of increasing public participation and interest in aviation-related activities in Turkey in general.

A row of Nu.D.36s at Yeşilköy Airport in 1942

The prototype of the Nu.D.38 undergoing construction in the early 1940s

Despite Demirağ's selfless efforts, he would soon be confronted with a government that not only failed to provide the necessary ecosystem for an indigenous aviation industry to flourish, but also one that actively worked against its very survival. Although the THK placed an order for 24 Nu.D.36s, a crash landing (leading to the death of pilot Selahattin Reşit Alan) after a test flight from Istanbul to Eskişehir led it to cancel its entire order for the aircraft. [3] In response, Demirağ started a lawsuit that dragged on for years, yet despite several expert reports attesting that nothing was at fault with the aircraft, the court ultimately ruled in favour of THK. [3]
In similar vein, the much-anticipated Nu.D.38 failed to attract any orders from the Turkish State Airlines (forerunner of Turkish Airlines), or any other government agency for that matter. To add insult to injury, a law was enacted that prohibited Demirağ from exporting his aircraft to other countries, halting negotiations with several nations that had shown interest in the Nu.D.36, including Spain. [4] This, combined with a lack of orders from the Turkish Air Force, forced the factory to close its doors in 1943. In an effort to overturn the situation, Demirağ made numerous appeals to government officials, including the president İsmet İnönü, ultimately to no avail. [3] Through no fault of his own, Demirağ's extensive efforts proved fruitless, ending what could have been a promising start of an indigenous aircraft industry. In commemoration of his services to Turkish aviation, in 2010 Sivas airport was named after him. Though recognition had better come late than never, it is safe to say that Demirağ remains an underappreciated figure in Turkish history.

This is where the story of Nuri Demirağ and his aircraft factory was thought to have ended. That is until researcher Emir Öngüner discovered the existence of another aircraft project by Demirağ and his engineering team in official Turkish and German archive documents several years ago: The Nu.D.40. By virtue of its unconventional design and the fact that a model of the aircraft underwent wind tunnel tests in Germany, it is perhaps all the more surprising that this aircraft was relegated to obscurity for so long.
Much of the information concerning the Nu.D.40 comes from the wind tunnel tests conducted by the Aerodynamische Versuchsanstalt (AVA) in Göttingen, Germany in 1938. After the conclusion of the tests, the AVA sent Demirağ a comprehensive 110-page report detailing the findings unearthed during the tests. [5] Due to a series of miscommunications, the AVA only managed to collect only a portion of the money it had originally requested however, and in 1940 gave away the confidential report on Nu.D.40 to two German aviation firms. [6]

Little is known about the configuration, engine types and proposed armament of the Nu.D.40. Designed during the run-up to World War II, any parts that couldn't be indigenously produced (most notably the engines and armament) would need to have been acquired from abroad, a nigh on impossible feat as war was raging through Europe. Ignoring this fact for the sake of what-might-have-been, two German aircraft engines and an armament suite of two cannons or heavy machine guns and two light machine guns appears to have been a plausible configuration.

Eventually, Emir Öngüner shared his discoveries with Turkish Aerospace (TAI) President and CEO Temel Kotil, who excitedly told him ''We should definitely build this aircraft!'' [7] A team was created and made a 3D digital model, after which production of a 1:24 scale model followed suit. The next steps include assembly of two UAV models of the Nu.D.40 in 1:8 and 1:5 scales. [7] Ultimately, a full-scale 1:1 replica model will be created, finally realising Demirağ's dream to see the Nu.D.40 flying.

In its proposed 1:1 replica configuration, the Nu.D.40 will be a remarkably similar sight to the Dutch D.23 single-seat fighter designed by Fokker during the same era (so much so that the header image is in fact a D.23 modified to resemble the Nu.D.40 in WWII Turkish Air Force livery). The D.23 project was first conceived in 1937 as an interceptor with a top speed of some 535km/h and an armament of two 13.2mm and two 7.9mm machine guns. A full-size mock-up of the aircraft was first presented at the 1938 Paris Air Saloon, followed by the completion of the prototype in March 1939. [8] The D.23 took to the sky for the first time two months later, but during its eleventh test flight in April 1940 it received damage to its nosewheel that had to be disassembled and shipped for repair. [8]
When the Germans invaded the Netherlands in May 1940, the nosewheel hadn't yet been repaired and the D.23 survived the invasion largely unscathed, stored in a hangar. Just two weeks after the conquest of the country, the Luftwaffe came to inspect the aircraft and prepare it for shipping to Germany. Not prepared to relinquish its promising project to the enemy that easily, Fokker pointed out to the German delegation that the D.23 was the possession of Fokker rather than the Royal Netherlands Air Force, and that if the Germans wanted it they would have to pay a hefty acquisition price, promptly ending German interest. [8] Ultimately, the aircraft was slowly taken apart by souvenir hunters and later destroyed in an allied air raid on Schiphol. Had the D.23 entered service, it would have been one of the most interesting aircraft of its era, but the outbreak of World War II prevented the aircraft from living up to the high hopes invested in it.

After years of painstaking research, Emir Öngüner collected all of his findings regarding the Nu.D.40 in the book 'Bir Avcı Tayyaresi Yapmaya Karar Verdim'. The book focuses on the design history of the aircraft using official documents collected from archives in Germany and Turkey. Although currently only available in Turkish, hopefully one day an English version will be available as well. Bir Avcı Tayyaresi Yapmaya Karar Verdim can be ordered for ₺40.00 at TÜBİTAK or at other any popular online bookstores in Turkey.
Turkey's first (unmanned) indigenous combat aircraft is set to enter service in 2021, some 83 years after the design of the Nu.D.40. As innovative as the Nu.D.40 was then, so innovative the Akıncı is now. Though Nuri Demirağ has nowadays been largely forgotten, others have picked up the thread of his visions for a modern indigenous aviation industry. Companies like Baykar Savunma demonstrate what a team of highly dedicated people can achieve; much like Demirağ they are risk takers, putting their country and a love of engineering first and the desire to make a lot of profit second. As Demirağ knew close to 100 years ago, generating public interest is key to these goals, and through its technology workshops and festivals such as Deneyap and Teknofest Baykar is sure to attract a host of likeminded spirits to its factory and other Turkish technology firms. With their eyes on the future, companies like these are transforming not just their country's destiny in the skies, but also in the minds of its people.

Bu Hikaye;

[2] TOMTAS - Tayyare Otomobil ve Motor Türk Anonim Sirketi
[3] Aviation Facilities of Nuri Demirağ in Beşiktaş and Yeşilköy
[4] The 24 Nu.D.36s that had been produced for the THK were donated by to the local flight school and later scrapped.
[5] Nuri Demirağ’ın Almanya’da kaybolan avcı uçağı: Nu.D.40
[6] Nuri Demirağ’ın Bilinmeyen Uçağı: Nu.D.40


  1. This is great thanks!

  2. Dostum harikasın, teşekkürler.... Yazık bize de, bizi biz anlatamıyoruz ya :(