The use of composite for the MС-21 wing gives a significant gain in several parameters at once, including the total cost of the airliner, said Yury Tarasov, Technical Director – Director of Production System Development and Quality Management Department of UAC to the press service of the United Aircraft Corporation.
The use of carbon fiber-reinforced plastic made it possible to produce a wing with a thin profile and greater elongation (not to be confused with length!) for the MС-21. According to him, the thinner the wing, the lower the aerodynamic drag, while the elongation of the wing – the ratio of its span to width – affects another component of the drag – the inductive drag created by the vortex tearing off the end of the wing. This type of drag makes a significant negative contribution to the aerodynamic performance of the wing. Inductive drag may be absent in an infinite-length wing, but this is an ideal case. In real life, inductive drag is reduced by installing vertical wingtips (winglets, sharklets, cyberlets) or by increasing the wing length.
Elongation of an aluminum wing on previous generations of airliners was about 8-9. “It was not possible to make the wing longer, because aluminium is a soft metal. To prevent the wing from bending under the flight loads, it would be necessary to increase its thickness,” explains Yuri Tarasov. – Such an aluminum wing would be so thick that its aerodynamic drag would eat up all the gains from the high elongation. CFRP, on the other hand, is a stiffer material. So a CFRP wing can have an elongation of 10 or 11, or even more.
For the CFRP wing of the MС-21 it was possible to achieve an elongation of 11.5. Due to this alone, the aerodynamic quality increased by 5 to 6 percent. As a whole, the composite wing of high elongation with a thin profile will enable the MС-21 to reduce fuel consumption by up to 8 percent compared to ABCs (Airbus, Boeing, COMAC). During its life cycle (about 20 thousand hours) a medium-range aircraft with the “classic” aluminum wing burns 140 thousand tons of fuel. Only due to the “black wing” each MС-21 can save more than 11 thousand tons of fuel for the same flight time. This figure will become a serious argument in choosing between the MС-21 and its “metal classmates”.
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The prototype MC-21, reg. 73051, which received PD-14 engines last year, has been painted in the United Aircraft Corporation’s new livery. On June 2, the aircraft returned from Ulyanovsk to the M.M. Gromov LII airfield in Zhukovsky. This aircraft, as well as flight 73056, was scheduled to take part in the MAKS-2023 air show. Despite the cancellation of the air show, the plans for repainting in the updated livery have not changed.
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On June 7, the MC-21-310 prototype aircraft, reg. No. 73055, flew from Zhukovsky to Irkutsk, where the IAP will partially replace foreign aircraft systems and components with domestic equivalents. The aircraft will be prepared for certification of the MC-21-310RUS version.
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The Irkutsk Aviation Plant is continuing to assemble the first six production MC-21-310 aircraft which will be handed over to the Rossiya Air Company by the end of 2024. In November, the certification of the import-substituted aircraft will resume; now Russian aircraft systems and components are being assembled on the aircraft. Yuri Slyusar, head of UAC, said this in an interview with the Rossiya 24 TV channel on June 17 within the framework of SPIEF-2023.
“In Irkutsk, the first six production planes are being assembled, which are being supplied to the Rossiya airline. At the same time, our colleagues in cooperation are completing tests of import-substituted systems, including avionics, communication equipment, air conditioning system, and landing gear struts. All of this will be installed on the aircraft, and we will begin testing the fully Russian MС-21 in November. Our task is to complete these tests during 2024, get approval for the main certificate, which we received back in 2021, and in 2024 begin supplying aircraft to airlines,” said Yuri Slyusar.
Provided the stated terms of import substitution completion and certification of the upgraded components are maintained, commercial operations on the MS-21 may start in late winter – early spring 2025. In the remaining year and a half it is required to increase the pace of manufacturing and delivery of domestic equipment both to the Irkutsk aircraft plant and to the Yakovlev Design Bureau’s Research and Design Bureau in Zhukovsky to replace the equipment and continue certification flights.
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Tomsk State University has developed technology that is used to manufacture ozone converters and oxygen generators for domestic aircraft, in particular they are installed on the MС-21 and Superjet New. Converters and generators are already being supplied in series. Previously such equipment was purchased abroad.
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Belarusian enterprises will supply components for the MС-21 and the Tu-214, their participation in the SSJ-New project is also expected. Agreements have already been reached for supply of 1,300 items of components for MС-21, 700-800 items for Tu-214.
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CEO of Aeroflot Sergey Alexandrovsky said on June 16 in the framework of SPIEF-2023 that the airline is ready to sign firm contracts for the delivery of MS-21 and Tu-214 in the near future. Agreements have not yet been reached, but are at a very high level of elaboration and coordination. “On MS-21 and Tu-214 there is the fourth quarter, December 2024. That is, all the deadlines which were originally announced by the manufacturer, and which I have already voiced, they are maintained, no one is adjusting them,” he said.
The agreement provides for the transfer of 210 MС-21, 89 Superjet New and 40 Tu-214 aircraft to Aeroflot on a lease basis from 2023 to 2030. The first two SSJ-New aircraft will join the carrier’s fleet next year, and the first six MС-21s and the first seven Tu-214s will be delivered starting in 2024.
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On June 22, the MС-21 aircraft b/n 73054 delivered the UAC delegation to Kazan by a service flight to participate in the meeting on the issues of aircraft construction. On June 21, at 14:00 the aircraft flew from Zhukovsky to Vnukovo-3. The next morning the liner flew to Kazan and in 1 hour 15 minutes landed at the airport of Tatarstan’s capital. In the afternoon, at the end of all activities at the Kazan aircraft plant MС-21 brought the delegation to VKO, in the evening of the same day the board returned to Zhukovsky. The aircraft was piloted by the crew of test pilots of Yakovlev design bureau.
In June, the MС-21 aircraft did not fly under the certification programme. The aircraft remained on the ground to replace the imported equipment with domestic equipment, its adjustment and testing for the resumption of certification flights.
