On the eve of the HeliRussia-2023 exhibition, UEC-Klimov JSC held a regular conference of the General Designer of the enterprise Vsevolod Eliseev. The purpose of the annual event is to communicate with operators of aircraft on which Klimov engines are installed. During the conference, the developer talks about the path he has traveled over the year, about measures to improve the reliability and resource of existing engines, about working on new modifications and new projects. The correspondent of Aviport, who attended the meeting, took the opportunity to learn about the progress of work on the engines of the TV7-117 family.
The road is decades long
Turboprop and turboshaft engines are a very conservative segment of the market, in which the appearance of fundamentally new designs is rare. Today, almost every successful family of gas turbine engines has a history in which dates are counted from the last century. However, the progress made in terms of increasing power characteristics, specific parameters and reliability, sometimes suggests that related engines, similar in appearance and having similar schematic solutions, can be attributed to different generations of aircraft engines.
The TV7-117 engine family is one of the clearest examples of how decades of work to improve the basic design lead to a noticeable improvement in parameters. The basic TV7-117S engine was designed in the 1980s and 1990s for use as part of the power plant of the Il-114 regional 60-seat aircraft. The type certificate for it was issued by the Aviation Register of the Interstate Aviation Committee in January 1997. The engine was distinguished by high specific indicators for its time (specific fuel consumption at take-off mode 200 g / hp * hour), achieved due to the parameters of the thermodynamic cycle. Subsequently, a modification of the TV7-117CM was created, the main difference of which was the use of a new digital automatic control and control system of the FADEC BARK-65 type. This innovation increased the reliability of the engine and its operational manufacturability, and also allowed to reduce the weight of the engine by about 20 kg.
The creation of a helicopter version based on the TV7-117 gas generator was also planned in the last century. Then the engine was tried on both to the Mi-38 helicopter, on which it eventually found application, and to the Ka-50/-52 family of helicopters. The type certificate for this modification was issued by AR IAC in July 2015, subsequently it was validated by FAVT in 2018. At that time, the take-off power indicators were reached at the level of 2800 hp, the 30-minute power mode was 3000 hp, and the 2.5-minute emergency mode was 3140 hp. Further work on improving the TV7-117V made it possible to implement the CR mode with a power of 3750 hp, which is the best indicator in relation to take-off power, obtained in the engine family and on the market. TV7-117V in the corresponding execution has already received the approval documents of the Federal Air Transport Agency of the Russian Federation.
The second generation of aircraft modifications of the TV7-117 family of engines was born already in the last decade, when work on the TV7-117ST for the light military transport Il-112B was launched. Soon it was decided, in order to unify, to implement a project to create a TV7-117ST-01 engine for the upgraded regional Il-114-300, and at the turn of the decades, the TV7-117ST-02 project also appeared for the promising turboprop regional aircraft TVRS-44, also known as Ladoga. TV7-117ST-01 was certified at the end of 2022, and certification of TV7-117ST-02 is scheduled for 2024.
The family of engines with indexes ST, ST-01 and ST-02 has important differences from the basic C and CM. A number of new materials and coatings are used in them. The bet on new production technologies has also yielded results. The low-pressure casting technology is used in the creation, first of all, of body parts, which have been lightened by 10-15%. In turn, the blades of the compressor inlet guide unit were created using selective laser sintering technology, which radically reduced the complexity of their manufacture, and it was also possible to facilitate this detail. It should be noted that the use of additive technologies is already in serial, not pilot production, the corresponding technical processes have been protected by the manufacturer.
Great progress has also been made in the creation of a new generation of automatic control and control units of the BARK. The aircraft versions use a unit that implements control of both the engine and the propeller, which increases the functionality and reliability of the system. Finally, the BARK provides a large amount of data necessary for the search and timely elimination of failures.
As V. Eliseev told reporters, innovations were also used in the process of designing the engine. Thus, measures were implemented to create a "digital double", with the help of which a number of virtual experiments were carried out. The most difficult of them are acceleration tests of rotors, blade breakage tests. The use of mathematical modeling made it possible to speed up and reduce the cost of development and testing, as well as optimize the design of the engine.
A large complex of works was implemented to improve the reliability of the engines. Fire safety measures have been implemented, for the replacement of titanium parts of the centrifugal compressor stator with steel ones, for engine supports. The effectiveness of the work was confirmed by tests on the stands, and design improvements developed for one of the engines of the family were implemented on other modifications.
The newest member of the TV7-117 engine family today is the version with the ST-02 index. It has a number of significant design differences from its predecessors, which were previously described in detail by the chief designer of the TVRS-44 aircraft Sergey Merenkov. According to him, the level of take-off power of TV7-117ST-02 is closer to the original TV7-117CM, that is, the main engine units will operate in a moderately stressful mode. The modification uses an electric engine start, which will allow the use of airfield units widely used at airfields of the Trans-Urals and the Arctic zone. A closed oil system is implemented when the oil pump, oil radiator and other units are a structural part of the engine, not the aircraft, and are mounted on the compressor housing. This solution radically simplifies and accelerates the replacement of the engine, increases the reliability of the power plant.
Plans near and far
On the day of the General Designer's conference, Rostec and Rosaviation issued press releases announcing the Approval of the main change to the TV7-117ST-01 Engine Type Certificate, which expands the engine's operating capabilities in altitude and flight speed. This is just one of the blocks of work aimed at improving the reliability of the engine and improving its characteristics.
The first-generation engines have a total operating time of about 60 thousand hours on the stands, during testing, as well as about 30 thousand hours in operation at Vyborg Airlines (TV7-117S engines) and at the Il-114LL flying laboratory owned by Radar-mms (TV7-117SM engines). Today, the operating time of the TV7-117CM lead engines exceeds 3 thousand hours. The second-generation engines were created in accordance with modern airworthiness standards set out in the Federal Aviation Regulations AP-33. Therefore, a large amount of testing work was carried out to ensure the certification process. At first they were carried out within the framework of the TV7-117ST project, then - under the contract for the creation of TV7-117ST-01. Testing was carried out at the CIAM and UEC-Klimov bench base, at the flying laboratory, directly on the Il-114-300 aircraft.
So, at the flying laboratory, about 40 flights were performed in four stages with an operating time of about 150 hours. The control system was worked out, the operation of the power plant at different heights and speeds was checked. A large volume of tests was carried out in the CIAM thermal shock chamber, where it is possible to simulate the operation of the engine at different heights and speeds. According to V. Eliseev, it was the completion in April 2023 of the next stage of testing at CIAM that allowed expanding the operational range to an altitude of 6000 meters, speeds up to 550 km/h in the temperature range from -40 to +45 degrees Celsius. "This will seriously increase the capabilities of experimental aircraft at the beginning of flight tests," he explained.
In 2023, it is planned to continue testing in the thermal chamber, as well as conducting other types of tests, including resource tests. This should make it possible to remove restrictions on overloads when used as part of the aircraft's power plant, and most importantly - to improve resource indicators. The immediate plans are to confirm in 2023 the resource of the aircraft version in 600, and then 1200 hours, and for the helicopter version - a resource of 800 cycles. Subsequently, the resource will be increased to 6000 cycles and hours both for modifications of the TV7-117ST engine and for TV7-117V. But even with the achievement of these indicators, the work on increasing the resource will not stop. The target level of 12,000 flight cycles and a high level of service life of the main parts will be achieved after 2030. The duration of the upcoming works In . Yeliseyev explained the need to gain experience in operating engines, conducting a complex of long-term bench tests, as well as autonomous tests of the main parts.
After obtaining Type Certificates for the main modifications and the consistent removal of restrictions on their operation, the key issue will be the deployment of serial production. As the press service of the United Engine Corporation reported earlier, in 2023, six engines will be provided to aircraft builders to ensure the testing of the Il-114-300, of which two are already "on the wing", and four more are being finalized after the first stage of testing. Also in 2023, pre-production of engines for three aircraft is planned, and starting from the first quarter of 2024, engines in serial form for three more aircraft will be released.
Plans for the production of TV7-117ST-02 engines have also been implemented incrementally. In 2023, at the beginning of the second half of the year, it is planned to produce two engines for bench testing, and by the end of the year - two more engines for installation on the first flight model TVRS-44. "This year, it was planned to manufacture engines for bench testing, and two engines for delivery to the first prototype aircraft. We are now on schedule," said V. Eliseev. Further, according to him, in the spring of 2024, engines for the second experimental Ladoga aircraft will be delivered, and then three additional engines - as a reserve to ensure the certification of the aircraft. The certification of the engine itself will be completed at the end of 2024. In the middle of the decade, the readiness of UEC-Klimov and other UEC enterprises included in the cooperation will be ensured to produce from 20 to 50 TV7-117ST-02 engines annually.
Regarding TV7-117B, according to V. Eliseev, the work is going on within the approved schedule for the current year.
Thus, by 2028-2030, UEC-Klimov and its partners will produce more than 100 units of TV7-117 engines of various modifications. Subsequently, these plans are likely to be revised upwards. As previously reported, the Ural Civil Aviation Plant sees the potential of producing 50 Ladoga aircraft and its modifications annually. The IL-114-300 will be mass-produced. Both programs will require replacement engines, repair kits, etc. The use of the TV7-117V is most likely not limited to the Mi-38 alone - the use of the engine on other promising platforms is being worked out. According to V. Eliseev, today work is underway to create a medium-sized multifunctional unmanned aerial vehicle, which is designed for the use of the TV7-117 engine family. Finally, UEC-Klimov considers the entire line of TV and VK engines as part of hybrid power plants (GSU). However, the HSU based on TV7-117 is not the nearest prospect, since, according to V. Eliseev, first it is necessary to work out the basic technologies on power plants of lower power, such as VK-650.
These circumstances allow engine builders to make bold plans for serial production. "If we take the supply of all engines of the TV7-117 family, it is planned to enter 50 sets in 2026-2027, then, by 2030, it will already be more than 100 engines," V. summed up. Eliseev. He also added that a production cooperation has been formed for the production of engines as part of "UEC-Klimov", PC "Salyut" of the United Engine Corporation, PC "Compressor", OMO named after Baranov, "UEC-STAR". A comprehensive production modernization program has been planned at all enterprises, for which funds are planned. Their receipt will significantly accelerate the work on promising projects.
Similarly, measures have been planned to provide after-sales service for TV7-117 family engines and support operators. A program was formed to bring engines to market, involving the creation of a pool of replacement engines, a pool of spare parts, the formation of an aviation training center for training technical personnel, as well as the creation of field offices for engine maintenance and repair. There is a selection of regions for the placement of warehouses and a training center, already now a negotiation campaign is underway with the United Far Eastern Airline Aurora for the operation of the Il-114-300 power plant and with the airline KrasAvia - on TVRS-44. Another negotiating position is the format of agreements in the after-sales service of engines - in the format per flight hour or under other contracts.
Summing up, it can be stated that the TV7-117 program is gradually completing the stages of OCD and reaching the milestone of serial production. It is likely that this family on a new historical turn can repeat the colossal success that accompanied the TV2-117 and TV3-117 engines, which stood on many thousands of helicopters of the Mi-8, Mi-24, Ka-32, Ka-52 families, and become one of the most massive engines in the modern production line of the UEC.