Pioneering Aircraft Prototypes of the Transition to the Modern Era in the Turkish Aviation Industry (1)

In this article, a period in the evolutionary development of the Turkish Aircraft Industry, which started in 1925 and has reached the present day, which can be called the intermediate transition period and in which the building blocks of the breakthrough period that has been becoming more evident since the recent past in the field of defense and aviation, will be explained with a little more generalization.

This period was previously called "pioneering projects of the modern era" within the framework of a certain logic, and the names of the scientists and engineers who contributed to this cause were mentioned [1].

In fact, in the first period, which we can call the "Classical Period" of the Turkish aircraft industry, which dates back to the foundation years of our Republic, organizations such as TOMTAŞ, THK and MKE took place. This classical period, which we now regard as a legend, came to an end in the 1950s. In addition to the THK aircraft factory, which was the leading public institution of this period, the names of private sector entrepreneurs such as Nuri Demirağ, Vecihi Hürkuş and Selahattin Alan can be counted [2].

After the classical period, which was ended in the 1950s, the "transition from the classical age to the modern age" stage to TUSAŞ, which was founded in the 1970s with the "Make Your Own Aircraft" campaign, and finally the foundation companies and companies of TAI, which was established in the 1980s, The period of private sector companies such as BAYKAR Makina and VESTEL Defense can be called the "Modern Era". The subject of this article is the pioneering projects of the "Modern Era" mentioned earlier, and in fact, it is the time period when the modern design infrastructure of today's successful manned and unmanned aircraft was established and the first experimental prototypes were developed.

Our national aircraft industry, which operates today as TUSAŞ (Turkish Aerospace Industries Inc.), was originally an Air Force Air Force that was established by Law in 1973 and collected donations with the "Build Your Own Aircraft" campaign, as mentioned above, after the 1974 Cyprus Peace Operation. Empowerment Foundation. TUSAŞ, a fully Turkish-owned company, established TAI (TUSAŞ Aerospace Industries), a Turkish-American joint venture, in 1984 with General Dynamics to produce F-16 aircraft after it started operating. After a short while, private reinforcement foundations belonging to all forces of the TAF, including land, sea and air, were united under the umbrella of the Turkish Armed Forces Foundation (TSKGV) in 1988. In the last stage, TAI acquired the American shares in TAI, which is a joint venture, in 2005, the English name of TAI was changed to Turkish Aerospace Industries, and finally, TAI and TAI were combined under one roof to form the only company known as TAI today.

The first TAI of the 1970s with the same name was a company with idealistic staff and goals, especially the late Yavuz Kansu, who made great efforts in this regard. However, in the first period following the establishment, he could not make the expected exit due to various political, economic and technological factors. The reasons for this are also an issue that needs to be addressed. To briefly mention without going too deep; It can be argued that in those years, Turkey did not have the financial, technological and intellectual power required to make a jet plane with a unique design. It can be added that our national market does not have the strength to resist international monopolies and the ability to resist certain conspiracy theories. However, the main decisive objective criteria should not be forgotten here: These objective criteria are the width of the domestic and foreign market for the aircraft industry, the logistics support capability, and most importantly, the country's GDP and its percentage in the world. It is a fact that our country's GDP was below the 1% threshold required (according to one view) to sustain the aircraft industry in those years. (Today, this value is 1.2% (2021) on a world scale. In the 1980s, it was only around 0.8%, which was below the 1% threshold required for the aircraft industry under these conditions).

At the beginning of the period starting from the mid-1980s, which we can call the modern period of the Turkish aircraft industry and the transition from the Public Factories model to the Foundation companies model, some of them remained only on paper, some of them came to the model or pre-feasibility stage, and some of them came to the prototype stage. However, there were some projects that could not reach the point of development and then marketing. To count among these, TAI's first original unmanned aerial vehicle UAV project, the UAV-X1 (1989-1992), which remained at the prototype stage, the UAV-XP (1995), which was proposed as a continuation of this but remained on paper without any support, the only remaining prototype stage. engine (Attack and Surveillance) aircraft TG-X1 (1996-1997), regional passenger aircraft (Aircraft) HD-19 (1994-1997), which remained in the cockpit mock-up stage, and ZİU (1997-2000), which was still in the prototype stage (Agricultural Spraying Aircraft) ) are available [3].

These planes were never developed, serialized. It could not come to the production or sales point, and only one of the designed prototypes was made and only pioneer test flights were carried out.

On the other hand, the computerized design of ANKA Unmanned Aerial Vehicle and EASA-23 certified HÜRKUŞ turboprop trainer aircraft, whose design-development-testing and certification processes have been successfully completed by TAI and exported and sold to our armed forces in the last period we refer to as the "Modern Era" in this article. It can be argued that in the establishment of the infrastructure and shaping the processes, the pioneering projects, which are the subject of this article, assumed the role of basic building blocks. Likewise, in the "Modern Era", unmanned aerial vehicles developed by BAYKAR Makina [4], one of the private companies that entered the market in addition to the publicly owned Foundation companies, were introduced to the national market, such as the Mini UAV, TB-2 and AKINCI, and the KARAYEL unmanned aerial vehicle and system developed by VESTEL Defense [5]. was also exported. Although the subject of this article is the pioneering projects whose prototypes were made but could not enter the market, the Mini UAV Project of BAYKAR Makina, which was used by the Turkish Armed Forces, will also be briefly discussed at the end of the article in terms of creating a bridge between the past and the present. The fact that this project is a groundbreaking one is that after the historical decision taken by the Defense Industry Executive Committee (SSİK) in 2004 that no foreign UAVs will be purchased from abroad, except for urgent purchases, in 2004, the automatic guidance and control algorithms produced with domestic facilities and automatic guidance and control algorithms are domestic software. It is the first UAV project.

TAI Design and Development Department

To go back to the TAI of 1984, the main purpose of the establishment of this new company was to manufacture the General Dynamics F-16 warplanes, the design process of which was initiated in the 1970s, with maximum domestic contribution (in addition to other countries such as the Netherlands, etc.) in Turkey. It was widely accepted that the company had to have a design capability over time, but the mechanisms needed for this were not planned and the project partner General Dynamics GD was not enthusiastic about it. The financial resources required for TAI to build Turkish-designed aircraft were not disclosed, and sufficient support was not yet received from the Defense Industry Support Fund, which is the most appropriate resource that can be used to achieve this. Despite this, a Design and Development (T&G) Division was established at TAI in 1987 with company resources.

TAI UAV-X1 Project (1989-1992)

The UAV-X1 unmanned aerial vehicle, which is the first original aircraft design project of TAI T&G Division, was launched in 1989 in order to keep up with the new technologies emerging from Israel and Western countries in this field, both in terms of proving itself for the division that did not have a specific strategy at the beginning. This project, which started with a very small budget of 278,000 dollars from the Undersecretariat for Defense Industries (SSM) at the time, later reached the level of 828,000 dollars with the additional contract of SSM. Since a design infrastructure has not yet been established in the UAV-X1 project, the design was started with an academic-level approach. After the conceptual design, the detailed design pictures were made on desktop PCs. Under the current circumstances, a complex CAD/CAM/CAE system and Digital Twin (Digital Mock-up or Digital Twin) were not available in the company. Computational Fluid Dynamics methods were used for aerodynamics and experimental databases were used for propellers. Wind tunnel and flow visibility tests of the UAV-X1 were performed at METU Aviation Department. In those years, there was not enough knowledge at the national level about automatic flight control or briefly autopilot and electronic systems. For this reason, the US-origin S-TEC autopilot system was purchased for the UAV-X1, and a foreign consultant was brought in for the assembly and testing of the system. In addition, two TAI personnel had received UAV piloting and system training abroad for remote control systems training. From the middle of the project, the foreign designer of the TG-X1 aircraft, which will be explained below, especially during the design revisions and flight tests phase, also joined the team.

Within the framework of the UAV-X1 project [6], only 2 prototypes were produced and both were put to flight tests. Flight tests, which started in Sivrihisar in the spring of 1992, continued in Denizli-Çardak in the summer. Issues related to the remote control of an unmanned aerial vehicle Various incidents, including occasional crashes, caused the UAV-X1 team to gain experience and mature. Finally, in the autumn of 1992, the project was terminated after a single flight in Afyon as an aerodrome tour.

Although some projects were written after the TAI UAV-X1 project, such as the UAV-XP (1995), as a continuation of this project, support from the Undersecretariat for Defense Industries at the time could not be obtained. Although American General Atomics GNAT 750 planes were procured with the exception of urgent purchase for more than 10 years after 1992, they did not get much efficiency. Finally, in 2004, the time A historic decision has been taken by the Defense Industry Executive Committee (SSİK) that from now on, no foreign UAVs will be purchased from abroad, except for urgent purchases. According to this decision, after the order of 10 IAI HERON, national design and development projects were started. Currently, one hundred percent domestically designed unmanned aerial vehicles, BAYKAR Makina TB-2 and AKINCI, VESTEL Karayel and TUSAŞ ANKA and AKSUNGUR aircraft also perform combat missions beyond reconnaissance-observation missions.

TG-X1 Project (1996-1997)

After the UAV-X1 project, a new project could not be started immediately in the original design class expected from the T&G Department. In fact, a project that could have a commercial potential on the one hand and an original design product on the other, could have been a light aircraft project. In order to be a temporary answer to the search for a new project and at the same time enable the design team to develop its own technical capabilities a little more, the "light attack" aircraft project, which is a new concept in the world, although not exactly original, was started. This project was designed as a project that would not open up financially, using TAI's own resources without assistance from SSM. From the point of view of TAI, on the one hand, it was decided to keep the UAV project team together without disbanding, and on the other hand, a local copy of the A-22 “Optionally piloted vehicle” developed by William Sadler, who came to TAI as a consultant in the UAV-X1 project. . Looking back on the history of the A-22, this aircraft initially won the "Grand Champion Design" award in Oshkosh, Wisconsin, with its Sadler "Vampire" model, which is still very popular with ambitious aircraft designers today. Subsequently, American Microflight transformed this model into a military one at the end of the 1980s (A-22) and developed a concept called Piranha [7].

The concept of “option-piloted vehicle” was actually the design of an unmanned aerial vehicle to be flown both as manned and unmanned, and thus to prevent accident-destruction events that may arise during the automatic flight control trials and automatic landing phases. The new aircraft, named as Assault-Surveillance-Experimental-1 (TG-X1) by TAI, was to increase the engine performance of the A-22 and make it armed.

It is necessary to briefly mention here the designer of the A-22 prototype, which has a distinguished place among the foreign experts who started to be employed in our country during the pioneering projects of TAI. He was originally from Canada and had his engineering degree in electronics engineering from MIT. Sadler, who told that he made his first television in high school years, was the head of a group of about 50 people at General Dynamics (GD), because the factory discipline bored him and he was "mad". He left and started his own business. Prior to his tenure at GD, he designed and raced the Sadler brand racing cars (which can still be seen on the internet) known by his own name. After his duty at Sadler GD, he became one of the founders of General Atomics, the producer of the famous UAVs, known today as GNAT, in San Diego, but since corporate affairs were not for him, he left there and founded the Sadler Aircraft company and developed the A-22 aircraft. The A-22 was originally a drug and anti-trafficking aircraft to serve on a US-Mexico border. It offered a very cheap solution compared to helicopter and turboprop aircraft with folding wings, capable of landing and taking off from short runways, and also had a manned / unmanned conversion.

The conceptual feature of the TG-X1 aircraft was that it offered a very economical option to be used in security operations instead of the attack helicopters that TAI started in those years and had great difficulty in supplying [8].

For this, it was envisaged that the A-22 aircraft would use a 450 horsepower aluminum block water-cooled 5.7-liter V-8 Chevrolet engine with forged titanium arms instead of a Rotax engine of around 100 HP. 1 piece of 12.5 mm on both wings. machine gun and Hydra rockets under the wing or one 12.5 mm on one wing. the machine gun would be able to carry a 30mm McDonnell Douglas M-230 cannon on the other wing. Thus, an economical option could be offered in security operations. Of these, the prototype of the M-230 gun was brought to TAI and working on how to attach it to the aircraft with shock absorbers, knowing the vibration and shock forces that this gigantic weapon would create. For this machine gun, which is also very serial, the shell chamber was planned to be just behind the pilot, close to the center of gravity. The aircraft's Kevlar-supported fuselage also protected the pilot from light weapons. Thanks to its foldable wings, the TG-X1 could be easily carried in the back of a truck and be ready for flight in 10 minutes. It offered very flexible solutions with its ability to land and take off on soil runways, and the wide viewing angle it provided to the pilot.

The project was undertaken by then TAI Deputy General Manager SSM Deputy Undersecretary Dr. Conducted under the auspices of Birol Altan NS. The project started in April 1996 and its first flight took place in May 1997. The design modification was made very quickly, since the shape of the aircraft was already clear due to both the tightness of the budget and the lack of time. According to the new engine, an engine stand and a reinforced wing for mounting the weapons were designed. When it was time for production, there was a big problem in terms of production method. W. Sadler, an old generation engineer, did not want to waste time, while TAI engineers wanted the manufacturing drawings and production of the aircraft to be done with the computer-aided modern CAD/CAM system used in TAI at that time. In fact, it was warm to the engineers in the group to quickly reveal the plane with the "Skunk Works" type approach instead of the very slow project logic using the big airplane factory logic. In the end, the project model could not be resisted and the plane was revealed in a very short time with the method called the "sculptor approach" by some engineers from the project group. Due to budget and time constraints, adequate analysis was not done during the design, because a prototype had already been made and flown within the framework of the A-22 concept. Thus, the project was completed in a short time, which could be called a record, and following the first flight in May 1997, the test flights were made first on the TAI Mürted (Akıncı) runway and then on the Sivrihisar square.

A flight demonstration was also held for a military delegation from the MSB on May 15, 1998 for the TAF, the closest potential customer of the prototype produced by TAI's own resources, but the mass production of the "light armed support aircraft" prototype, which was not fully accepted at that time, was not successful. . Sadler's original design A-22 and the concept of the TG-X1 armed adaptation in TAI were justified after a long time. The South African Paramount designed AHRLAC (Advanced High-performance Reconnaissance Light Aircraft) and its armed attack model MWARI aircraft were very similar to the TG-X1. This shows that when the TG-X1 aircraft was introduced in the 1990s, it was too early for such a concept. However, we think that if our aircraft industry had been supported to work on this concept at that time, we as a country could have reached the point where the world is today much sooner.

(To be continued)

References
1) Source, Ü. “Pioneering Projects of the Modern Era of the Turkish Aircraft Industry”, Turkish Aviation Success Stories Workshop, 19-20 April 2018, Atılım University.

2) Yalçın, O., History of Turkish Air War Industry, Doctoral Thesis, Gazi University Institute of Social Sciences, Department of History, Department of History of the Republic of Turkey.

3) Deniz, T., http://www.tuncay-deniz.com/ENGLISH/TAI/tai.html.

4) BAYKAR Makina, https://www.baykartech.com/tr/insansiz-hava-araci-sistemleri/

5) VESTEL Defense, https://www.vestelsavunma.com/tr/cozumler/insansiz-hava-araci-sistemleri.

6) Kıcıman, M.O.. “UAV-X1 Project”, Success Stories Workshop in Turkish Aviation, 19-20 April 2018, Atılım University.

7) Sadler, W., https://en.wikipedia.org/wiki/Bill_Sadler_(engineer)

8) Kaynak, Ü., “TAI TG-X1 An Inexpensive Effective Solution for Limited Military Operations”, Developments in Terror and Security Operations and Evaluation of Tools, Equipment and Weapons Used in Country Events, Black Force. com. Ord. Arrow. and Eğt. Central Committee, 1-2 October 1997, Balikesir.