Pioneering Aircraft Prototypes of the Transition to the Modern Era in the Turkish Aviation Industry (2)

In our previous article, we talked about the establishment process of TAI, its structuring as TAI, and the pioneering design and development projects in TAI. In this context, we have briefly presented the studies on TAI UAV-X1 Project (1989-1992) and TG-X1 Project (1996-1997) for your information. Now, we would like to talk about three other projects made at that time.

HD-19 Regional Passenger Aircraft Project (1994-1997)

After the UAV-X1 project, a new project could not be started for a long time. Meanwhile, TAI was considering what could be done in the civil and commercial areas, apart from just defense projects. In fact, the truth of this matter was that there was a demand from the market, especially THY, operating in the transportation sector, and that there was a responsible person who would undertake the cost of the design and development process. Moreover, in such projects, it was necessary to have a customer who guaranteed a certain number of first purchases from the project.

In those years, Turkey did not have the opportunity to initiate such a project, due to the lack of an aircraft development infrastructure to achieve this task, and financial resources to spare for this work. On the other hand, the rapid development of aviation in the world and the great promise of the regional aircraft market, and the planes such as Bandeirante and EMB-120 developed by companies such as Embraer, which have just started to make their names known, showed a way that such aircraft could be made in Turkey. As a matter of fact, TAI Deputy Director General of the time, Dr. Birol Altan's foresight and the concept of a Regional Passenger Aircraft called HD-19 were introduced in order to promote such a project, and first a full-scale, one-to-one scale model of the pilot's cabin was made.

HD-19 TECHNICAL SPECIFICATIONS
Mission: Passenger-cargo transportation
Engine Type : 2 P&W PT6F-3
Engine Power: 1800 SHP
Maximum Speed: 600 km/h
Range : 1377 km
Takeoff Weight: 8544 kg
Curb Weight: 5560 kg
Wing Area: 35.15 square meters
Height : 5.70 meters
Wingspan : 20 meters
Length : 17 meters
Crew: 2 pilots
Flight Ceiling: 9 thousand meters

The HD-19 conceptual design was made by Ali Behiç Güventürk, again, as in the UAV-X1 project. The most striking aspect of the design was that although the aircraft was a turboprop, it was not very necessary, but the nose of the aircraft was sharper, like higher speed turbofan aircraft, and this gave the aircraft a different air. Unfortunately, when it was revealed that approximately $300 million was required for the preliminary design and prototype of the aircraft in that day's money, and there was no customer on the horizon, this project was limited to conceptual design drawings and only a one-to-one scale model of the pilot cabin. In fact, it was heard that Embraer company came to TAI and offered a partnership in those years, but it seems that Turkey did not have the courage and financial resources to undertake this risk.

One of the most influential names among the foreign consultants invited to TAI within the framework of the projects described in this article's time period is William Sadler [9], the designer of the TG-X1 and A-22 Piranha described above, while he was the chief engineer of Embraer and invited for HD-19. It would be very useful timing to have a Brazilian team of 3 including himself under the chairmanship of Guido Pessotti, who was released due to his bad relationship with Embraer and came to TAI. Under the guidance of Guido Pessotti, TAI's young engineers trying to gain experience in aircraft design, the first HD-19 aircraft designed by TAI was transformed, and the concept of turboprop engine was switched from concept to turbofan engine. Parallel to this, the concept of 2 engines placed under the wing, similar to large airplanes, was adopted instead of 2 engines placed at the rear of the fuselage, which was the most important concept change of its time. Later, the concept of the 19-seater aircraft evolved further due to the lack of market and customer potential, and the "family concept" with 30-, 50- and 70-passenger capacities, respectively.

More interestingly, Pessotti and his team, who went to Dornier company after leaving TAI, continued the same “family concept” model there and first participated in the development of the turbofan-engined Do-328J aircraft instead of the turboprop-engined Do-328, and then 50+, 70+ and 90+ respectively. It is the foundation of the Do-528, Do-728, Do-928 family with passenger capacity. Unfortunately, these planes could not be realized because at that time the Dornier family had withdrawn from this business and sold the company to Fairchild. In 2015, this project came to Turkey's agenda again in a very different way: The Sierra Nevada Corporation (SNC) company of Eren and Fatih Özmen, whose owners are Turkish and who bought the Fairchild company, signed a protocol with the Undersecretariat of Defense Industries of the time, It was announced that the 328J aircraft would be produced and marketed in Turkey under the name TR-328. However, this attempt was also unsuccessful and it is understood that it was shelved in 2017.

Agricultural Spraying Aircraft, ZİU (1997-2000)

Although it is an ambitious naming, thanks to the TG-X1 project. A propeller piston engine airplane prototype was produced and flight trials were carried out with the "Skunk Works" approach, or an approach that could actually be called a workshop type, but it was not in a position to get registration from the national civil aviation administration DGCA. The shortcoming here was double-sided. TAI did not prepare a data file to be submitted to the aviation administration, as the design and development project plan was not prepared considering the certification rules. On the SHGM side, there was no personnel, organization and knowledge to manage the certification process of a domestic aircraft at that time. In contrast, the conceptual design of the HD-19 project was made under the computerized design/production/engineering system that was started to be established at TAI and under the modern design rules with the support of the aforementioned former Embraer chief designer Guido Pessotti and his accompanying Brazilian consultants. The Agricultural Spraying Aircraft ZIU project, which was started based on this experience, was now approaching the maturity to be done by considering the certification database file for TAI. As a matter of fact, although no application was made to the DGCA in this project, the design, production and flight tests were carried out under the old JAR-23 or EASA CS-23 rules, to which DGCA was affiliated.

There was a great need for agricultural spraying aircraft throughout the country, and the market in Islamic countries, also known as the D-8 in the international atmosphere of the time, provided the necessary depth for the sales and marketing of such an aircraft. Considering this situation, T.C. The preliminary design specification of the Agricultural Fighter Aircraft was published on April 1, 1997 by the Office of the Prime Ministry Chief Advisor [10]. TAI, THK and universities were among the bidders for the Technical Specifications. At the end of the process, TAI was determined as the most suitable institution to carry out the project. A domestic design aircraft project that would meet the national need and also find a place for itself in the international market and be economical was an important milestone for the Turkish aviation industry of the time. A successful example of inter-institutional harmony was shown in the initiation of this project, and among those who contributed a lot to the project, the late Prof. Dr. Assistant to Necmettin Erbakan from the ITU Engines Chair, Prime Ministry Chief Advisor Assoc. Dr. Sedat Çelikdoğan and former SSM Vice President and then TAI Deputy General Manager Dr. There is Birol Altan [11].

After the conceptual and preliminary design studies started by TAI in 1997, detailed design in 1998 and production in 1999 started, the first flight was made on 26 June 2000. The most important feature of the aircraft was the use of the Canadian Orenda OE-600 engine, which was the most powerful water-cooled piston aircraft engine of the time, with 600 HP, instead of turboprop engines, which were very powerful but increased the price of the aircraft. Thus, it could provide the highest spraying weight at the most affordable price compared to its peers [12]. The project initiated by TAI was not continued due to the change of time and the cessation of public support while the flight tests were continuing [13]. Failure to continue the project is a real loss for our domestic aircraft industry. However, when viewed within the logic of "leading projects of the modern era", which is the subject of the article, HÜRKUŞ, which was the first aircraft developed by TAI and received EASA CS-23 Certificate, has design sub-systems such as software, hardware, design methods, process, ground and flight tests. is the project where the structure was established.

Bayraktar Mini UAV (2004-)

The "pioneer projects", which are the main subject of this article and introduced above, were preparation projects for the modern period and aircraft projects that reached the prototype stage but could not be commercialized. On the other hand, BAYKAR Makina's Mini UAV Project was a groundbreaking project in terms of creating a bridge between the past and the present, as the systems that belong to the period we call the modern period and that are both included in the Armed Forces structure and exported. 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 under any circumstances, except for urgent purchases, it was the first domestic software to be produced with automatic guidance and control algorithms. It was a UAV project. The project process is initiated with the Call for Proposals File (TÇD) published by SSM on July 25, 2005 and states that "only domestic companies can participate in the tender", "Technology transfer and/or production under license proposals to be given under the Mini UAV Program will not be evaluated", and "Mini UAV Program will not be considered". It was stipulated that domestic companies that would originally develop and manufacture the body and autopilot of the Mini UAV System could submit bids”, “Companies that could not originally develop the body and/or autopilot of the Mini UAV System cannot participate in the Demonstration Stage” and “The bids of the companies that cannot pass the Demonstration Stage will not be taken into consideration”. [14]. The prototype developed by BAYKAR Makina successfully performed the autonomous flight demonstration at TAI facilities on October 24, 2005 and won the Mini UAV Project. Prototypes used in the Proposal and Demonstration Stage presented by BAYKAR Makina were started to be developed by the Company since 2003, and the interim results were presented at domestic congresses [15].

The main point that makes the BAYKAR Mini UAV project so successful is that, in addition to combining the cutting-edge technology of the time in terms of software and hardware with domestic facilities, the development flight tests of the BAYKAR project team, especially the founder and leader of the company, Özdemir Bayraktar, are carried out in the field with the close support of our Armed Forces and the opportunities provided by the user. . Since 2004, BAYRAKTAR Mini UAV has undergone a major change in terms of design features with the experience gained from field use. While the airplane was originally designed with 2 attractive propellers on the wing, double fuselage rods and an inverted V-tail, the modern airplane still in use has a single V-tail, a single fuselage stick and a straight V-tail located at the rear of the fuselage. Perhaps the most important achievement of BAYRAKTAR Mini UAV, which should be mentioned here, which is a first in the design and production of domestic unmanned aerial vehicles, is that it broke the foreign monopolies formed in the past and proved that the most modern concept of its age, including software and hardware, can be put forward with domestic facilities.

References

1) Aviation Week and Space Technology, February 2018 issue.

2) "Preliminary Design Specification of an Exportable Agricultural Fighting Aircraft for Turkey's Needs in the Scope of Determination and Application of the Most Economical Agricultural Spraying Method", 1 April 1997, T.C. Office of the Prime Minister's Office.

3) Korkem, B. “Agricultural Spraying Drone Design, Production and Flight Tests”, Turkish Aviation Success Stories Workshop, 19-20 April 2018, Atılım University.

4) Özbek, T., www.kokpit.aero.

5) AGRICULTURAL AIRPLANES, http://www.defenceturk.com/index.php?topic=8097.0.

6) MINI UAV PROGRAM TENDER ANNOUNCEMENT, Project Name: Mini Unmanned Aerial Vehicle (UAV), Presidency of Defense Industries, TÇD Publication Date: 26 July 2005.

7) Bayraktar, S., Bayraktar, H., “An Unmanned Aircraft Project from Ideal to Reality,” HITEK 04 Symposium, Air Force Academy, 2004, Istanbul.