ATAK-II Heavy Class Attack Helicopter Project & the 3,000shp Turboshaft Engine Requirement

Issue 102

During the visit of a group of 250 people consisting of students and Foundation donors to the Turkish Aerospace Industries (TUSAŞ) facilities on September 28, 2017, for the 30th anniversary of the Turkish Armed Forces Foundation (TSKGV), President & CEO of TUSAŞ, Prof. Dr. Temel KOTİL made the first public announcement of the ATAK-II Project and said, "The current ATAK helicopter is 5 tons. We also started a larger 8-ton ATAK Helicopter Project as a concept." Also, on October 3, 2017, about a week after KOTIL's announcement, President of Defense Industries (SSB) Prof. Dr. İsmail DEMİR made a speech at the Alp Aviation Helicopter Business Center Opening Ceremony and pointed out that the helicopter would be in the 6-ton class. DEMİR said, "I would like to announce that the design process of a heavier and more agile helicopter, which will be the big brother of the ATAK helicopter, has started." The first CGI renders of ATAK-II were released to the public by TUSAŞ at the end of October 2017.

At first, the empty weight of the ATAK-II was planned to be 6 tons with a maximum takeoff weight of 8 tons; thus, two 2,000 shaft-horsepower (shp) turboshaft engines would be able to provide sufficient power. This demand could be met through the T700-TEI-701D Turboshaft Engine manufactured under license at the TEI facilities with a 61% national contribution rate under the T70 Turkish Utility Helicopter Program (TUHP), as well as through a new version of the TS1400 that could generate 2,000shp with a design change (TS1400 can produce 1,660shp for 30 seconds in case of an emergency or a single engine shut down). In a statement he gave for ATAK-II in June 2018, TEI General Manager Mahmut AKŞİT stated that the T700-TEI-701D Engine could be used on a national platform after a series of design changes. The T700-TEI-701D Engine was able to meet the power requirements of ATAK-II, which was projected as 6-8 tons. Besides, Turkey also has the right to make changes to the engine. Therefore, it would be possible to use the engine in ATAK-II by making the necessary changes to the engine for ATAK-II and adding these changes to the license agreement after reaching a deal with General Electric.

The T129B Mk-II/ATAK-II Heavy Class Attack Helicopter Project Contract was signed between the Presidency of Defense Industries (SSB) and TUSAŞ on February 22, 2019, to meet the needs of the Turkish Land Forces Command. However, the weight of the ATAK-II Helicopter, which had been planned to have an empty weight of 6 tons and a maximum takeoff weight (MTOW) of 8 tons, was later updated to 10 tons. The T129B Mk-II Heavy Class Attack Helicopter, which is stated to have approximately twice the takeoff weight of the T129B Mk-I, is expected to perform its first test flight 5 years after the contract enters into force (To+60 months). With the latest changes, the T129B will take its place among the top-class attack helicopters, of which there are only two examples in the world (the USA, Boeing AH-64D/E Apache MTOW 10,432kg and Russia Kamov Ka-50/52 MTOW 10,800kg). The duration of the project is envisioned as 8.5 years (To+102 months), and it is planned to develop two different types of Heavy Class Attack Helicopter configurations in the 10-ton Class (Naval and Land) and to deliver three prototype helicopters to the SSB together with the Technical Data Package (TDP). The 3,000shp TS3000 turboshaft engines to be used in the serial production T129B Mk-II/ATAK-II Helicopter are currently being developed by TEI.

The main technical specifications of the T129B Mk-II/ATAK-II Heavy Class Attack Helicopter are given as follows:

10-ton class (with a MTOW of 12 tons),

2 Turboshaft engines,

Weapon stations: 6 x underwing hardpoints,

Maximum payload: 1,200kg, excluding launchers,

Tandem cockpit,

4-axis autopilot,

Service ceiling: 20,000ft (6.096m)

Maximum speed: 318km/h

Operational envelope: -40/+50 C

Armor: 12.7mm-resistant armored cockpit,

Laser-based Helicopter Obstacle Detection System (HETS) and Fire Control Radar (MİLDAR),

Hot & High Performance,

Resistant to environmental factors,

High forward speed limit,

Advanced electronic warfare and countermeasure systems,

High-caliber cannon (30mm), new generation 2.75-inch rockets, long-range and anti-tank missiles with different guidance systems and air-to-air missile systems.

The first mock-up of the 10-Ton Class ATAK-II Helicopter in its new form was exhibited at the IDEF‘19 Fair. During the press briefing held on May 2, 2019, at the fair, President & CEO of TUSAŞ, Temel KOTİL informed press members about the work and projects carried out by Turkish Aerospace and in response to one of our questions, he stated that a new engine was needed for the ATAK-II Helicopter and that there would be two engines on the helicopter, each with a capacity of approximately 3,000shp. KOTİL stated that although there is no project for the engine yet, that engine will also be built locally, but prototype helicopters will fly with COTS (commercial off-the-shelf) engines as in GÖKBEY T625. 

In his statement published in a newspaper on May 8, 2019, Vice President of TUSAŞ R&D and Prototype Operations Prof. Dr. Fahrettin ÖZTÜRK stated that the ATAK-II will be a competitor to the AH-64 Apache and said, "We will equip the ATAK-II with new designs, technologies, and systems. We expect its maneuverability to be better than the others. It will be able to carry 1.2 tons of payload and will weigh 10 tons." The Boeing product, the AH-64 Apache Helicopter in the US Army inventory, has surpassed over 4.6 million flight hours with more than 1 million hours in combat environments since it first entered service in January 1984, and the company has delivered more than 2,400 Apache Helicopters to its customers in 17 countries around the world. The AH-64D/E Heavy Attack Helicopter has an empty weight of 5,165kg (11,387lb), primary mission gross weight of 6,838kg (15,075lb), loaded weight of 8 tons (17,650lb) and a maximum takeoff weight of 10,432kg (23,000lb). Powered by 2 T700-GE-701D turboshaft engines with each producing 2,000shp, the AH-64D/E Attack Helicopter has a maximum speed of 158 knots (293km/h), cruise speed of 143 knots (265km/h) and a service ceiling of 20,000ft (6,096m, with minimum payload). The AH-64D/E Apache Helicopter's thrust-to-weight ratio (TWR) is 384.6shp/ton, while the TWR of the 5-ton class T129A/B Mk-I is 537.5shp/ton (empty weight 2.9 tons, maximum takeoff weight 5.05 tons). The thrust-to-weight ratio of the 10-Ton Class ATAK-II, which is announced to be powered by two 3,000shp turboshaft engines, is expected to be 600shp/ton (it would be around 500shp/ton with 12-ton MTOW). 

In his statement to Anadolu Agency on December 29, 2019, President & CEO of TUSAŞ Temel KOTİL announced that the ATAK-II Heavy Class Attack Helicopter would make its maiden flight in 3 years. In another statement made on April 21, 2020, KOTİL shared that a foreign 3,000shp engine will be used in the ATAK-II in the first phase but noted that the development of an indigenous engine is also on the agenda as part of the project.

Speaking at the radio show "Domestic and National" on TRT Radio 1 on December 4, 2020, the President & CEO of  TUSAŞ, Temel KOTİL, said that, unlike the T129 ATAK Helicopter, whose gearbox, 20mm Gatling type cheek gun, and landing gear are procured from Italy, and the engines are procured from the USA, all parts of the ATAK-II Helicopter, including the gearbox and engine, will be locally manufactured and it will be even heavier than the US-made AH-64 Apache Helicopters. KOTİL said, "Our helicopter is 12 tons; it is heavier. It has a weapon load capacity of around 1,200kg, and this is around 300kg in ATAK. So it will be a bigger brother." Noting that ATAK-II is considered for the Turkish Land Forces and Gendarmerie General Command, as well as the Naval Forces (for TCG Anadolu LHD or future aircraft carrier), KOTİL said, "ATAK-II Heavy Attack Helicopter is planned to make its maiden flight on March 18, 2023, and to be delivered in 2025."

Preliminary studies for the 3,000shp TS3000 Turboshaft Engine to be used in the T129B Mk-II/ATAK-II Heavy Class Attack Helicopters started in the second half of 2019. TEI General Manager Faruk AKŞİT also conducted an interview with a TV channel on December 9, 2019 and announced that the work on the TS3000 had begun. The TS3000 Engine, which has been developed by TEI, is expected to also be used in the 10-Ton Class Utility Helicopter Project to be developed by TUSAŞ. The 10-Ton Class Utility Helicopter is expected to have a maximum speed of 170 knots and a cruise range of 1,000 km.

Using an indigenous turboshaft engine in the ATAK-II Helicopter will also increase the platform's export prospects globally.  License restrictions for the engine were the most crucial obstacle in the export of the T129 Mk-I ATAK Light Attack and Tactical Reconnaissance Helicopter, which is powered by two 1,361shp (given as 1.373shp on TUSAŞ' website) LHTEC CTS800-4A Turboshaft Engines. In 2015, 2 T129 Mk-I exports to Turkmenistan could not be finalized due to engine export license issues. Similar problems have also been experienced in the Philippines Air Force T129B Project and the Pakistan Army’s T129B1/B2 Mk-I ATAK Project.  The Philippines Air Force plans to procure 6 T129B helicopters, despite problems experienced in getting the export license for the engine from the U.S. Government in July 2020 the Philippine Department of National Defense (DND) has reaffirmed its plan to procure 6 T129 ATAK Helicopters from TUSAŞ but underlined that they would seek guarantees from Turkey about the platform’s export availability. Philippine Defense Minister Delfin LORENZANA disclosed that they have allocated a budget of US$258 Million for the procurement program. 30 T129B1/B2 Light Attack and Tactical Reconnaissance Helicopters were ordered for the Pakistan Armed Forces under a contract of approximately US$1.5 Billion signed on May 16, 2018 (10 T129B1 and 20 T129B2. The B1 helicopters would later be upgraded to the B2 level, and it may be possible to deliver all helicopters in B2 configuration as the project has been delayed). However, as of July 2020, the deliveries have not yet been started in the project due to the inability to obtain the export license required for the CTS-8004A engines from the U.S. Government.

On September 25, 2020, the President of Presidency of Defense Industries (SSB) Prof. İsmail DEMİR made an exclusive statement in our magazine and shared important information regarding the current status of the export license issue. He said: “So far, we have not experienced any drawbacks in the Pakistan engine export license process. Nor do we expect any problems in the process of the Philippines. However, especially in the Pakistan process, the U.S. authorities’ rejection of granting export licenses would cause a loss to all three parties, the U.S., Turkey and Pakistan. We believe in common sense and we hope there would not be any abdication of reason at this stage. The indications we have been receiving from the U.S. imply a positive approach. We have not received any adverse signals to date, but definitely we need to wait for the result.”

A Look at  3,000shp-Class Engine Solutions Available on the Market for the 

ATAK-II Heavy Weight Attack Helicopter Program

As stated above, as in the T625 GÖKBEY Turkish Light Utility Helicopter (TLUH) Program, ATAK-II Heavy Class Attack Helicopter prototypes (3 units) are also planned to be powered by foreign COTS (commercial off-the-shelf) engines, and TEI product TS3000 engines are intended to be used in serial production helicopters. 

As will be remembered, 10 CTS800-4AT Turboshaft engines were purchased from the Light Helicopter Turbine Engine Company (LHTEC), a joint venture between Rolls-Royce and Honeywell, for 4 (P0, P1, P2, and P3) prototypes to be manufactured under the T625 GÖKBEY Program. In parallel, under the Turboshaft Engine Development Project, the contract of which was signed on February 7, 2017, the TS1400 Turboshaft Engine with similar capabilities and power capacity is being developed by TEI. The TS1400 engine, which does not contain any parts subject to export restrictions (ITAR-Free), can be used in the T129B Mk-II ATAK Helicopters in addition to the T625.

According to open sources, the main 3,000shp (2,235kW) class turboshaft engine candidates and manufacturers that can be used in prototype helicopters under the ATAK-II Heavy Class Attack Helicopter Program are:

General Electric (GE) Aviation (T901, CT7-8 and YT706)

P&W / Honeywell ATEC Partnership (T900 / HPW3000 Engine)

Safran Helicopter Engines (Aneto Engine Family)

GE Aviation T901-GE-900 Engine & US Army ITEP

Note: You can attain the detailed information about the Heavy Attack Helicopter Engine configurations and pdf version of articles in our 102nd issue...



As summarized above, GE Aviation's T901-GE-900 engine, one of the 3,000shp turboshaft engines currently available in the market or in the delivery phase, is a new generation engine developed for the U.S. Army, so it is not expected to enter the export market in the near future. The ATEC T900-HPW-900 engine, which competed against the T901 in the ITEP tender and lost, is not currently in production. In this context, technical support may be obtained from ATEC for 3,000shp engine technology. As T901 and T900 options are out of the list, the only off-the-shelf foreign engine options available for use in ATAK-II Heavy Class Attack Helicopter prototypes are GE Aviation product 2,638shp (1,967kW) YT706-GE-700 engine, 3,000shp YT706-GE-700R engine, 2,300kW (3,070shp) CT7-8C/CT7-8A7 engine and Safran Helicopter Engines product 2,500shp Aneto-1K/1X engines.

As in the T901 example, the TS3000 engine development studies that were initiated by TEI in the second half of 2019 can be expected to focus on a T700-TEI-701D based (engine core) turboshaft engine with a single-spool design, which is being manufactured under license with 61% domestic contribution (maximum single-engine power 2,000shp for 2,5min, maximum power 1,994shp for 10min, intermediate power 1,902shp for 30min and maximum continuous power 1,716shp). Thus, it may be possible to develop a lighter and more cost-effective engine, while the development schedule can be reduced to more reasonable times.

Furthermore, after having the capability to manufacture an indigenous jet/gas turbine engine core under the TS1400 Turboshaft Engine Project, TEI will also be able to manufacture a larger engine by scaling this core. In terms of special process manufacturing capability, TEI became the first among 3,672 NADCAP accredited companies with 10 different special process groups and 52 process accreditations in October 2017. Having reached a certain level of proficiency in compressor technologies, which are very difficult to gain, TEI achieved a combustion chamber efficiency of over 98% at the TEI-TS1400. Like the LHTEC CTS800 engine, the TEI-TS1400 engine also has high-level weight and volume optimization. The engine consists of 2 Radial Compressors, a Reverse Flow Combustion Chamber, a two-stage High-Pressure Turbine (HPT), and a two-stage Power Turbine (PT). Therefore, unlike the T700, the TS1400 has a dual spool design (the compressor and high-pressure turbine are both split into two segments). Aimed to power Turkey's first Medium Range Anti-Ship Guided Missile, the TEI-TJ300 Turbojet Engine has a 4-stage axial compressor and a single-spool axial flow design, which generates 1300N thrust and approximate 400 shp. TEI currently has the technology to design and manufacture axial flow compressors and already has an indigenous, high mass flow rate centrifugal compressor design. The company had previously established the infrastructure to design, manufacture, and test 5-stage axial blisks with a complex geometry under GE's F136 and LEAP engine projects. Therefore, TEI has been working on the super-efficient centrifugal compressor design for about ten years. The most striking feature of the T700 engine, which is well known by TEI, is that it has a centrifugal High Pressure (HP) compressor after the axial compressor stages. The Low-Pressure Centrifugal Compressor in the TS1400 Engine is considered to have similar dimensions to the HP Centrifugal Compressor in the T700. 

In conclusion, TEI is capable of developing and producing the TEI-TS3000 Turboshaft Engine (3,000 shp) with its knowledge and infrastructure in engine technologies as well as the Additive Manufacturing Techniques implemented in the production processes since 2013. I believe that the development and prototype engine production process will be completed by 2025, and the ATAK-II Heavy Attack Helicopter (expected to perform its maiden flight on March 18, 2023, with foreign engines) will use the national and indigenous TEI-TS3000 engines after a certain number of helicopters are delivered with foreign engines in the serial production phase, which is aimed to start in 2025.

I would like to thank my dear friend Kubilay YILDIRIM, who shared his technical knowledge about engines with me in the preparation of my article