Russian Composites for MC-21 Withstood a Load 1.5 Times Higher Than Normal — Imported Ones Collapsed Earlier

The United Aircraft Corporation (UAC, part of Rostec) published preliminary characteristics of the MC-21-310 medium-range airliner in an import-substituted version about a month ago. The flight range unexpectedly decreased from the initially declared 5100 km to 3830 km.

After that, the opinion went viral on the Web that the reason for the overweight could be too heavy composite materials of Russian production. «The First Technical» tried to figure out whether our composites are so bad in comparison with foreign ones?

Tests Confirmed the Advantage of Russian Materials

The Central Aerohydrodynamic Institute (TsAGI, part of the National Research Center «Institute named after N. E. Zhukovsky») announced the completion of a series of static and local tests of the stabilizer for the MC-21-310. All elements were made of Russian polymer composites developed as part of an accelerated import substitution program.

The main goal of the experiment was to check whether the domestic composite caisson could withstand real operational loads, including emergency modes. The test was carried out on a stand completely identical to the one used for the imported sample.

So: the result was much better than expected. The Russian design withstood loads 50% higher than calculated. The imported sample collapsed much earlier.

Our Caisson Withstood Loads 2.5 Times Higher Than Normal

During the tests, specialists consistently increased the loads, controlling the behavior of critical components — attachments, elevator, and stabilizer adjustment mechanism.

The caisson made of Russian composite materials showed high reliability, working at loads that exceeded the maximum permissible by 150%. This is a unique achievement, confirmed for the first time for a part of this class.

Import Substitution Accelerated

After the cessation of supplies of critical foreign composites, Russian enterprises under the management of UAC launched their own developments.

Now most of the structural elements of the MC-21 are produced inside the country, and the certification of the airliner is in full swing.

The Load on the MC-21-310 Will Systematically Decrease During Operation

Executive Director of the AviaPort agency, aviation expert Oleg Panteleev, also explained to «The First Technical» that the weight of the MC-21-310 is related not only to composites. He recalled that it was necessary to change all onboard systems and introduce domestic solutions.

However, enterprises have not produced such components for a long time, so the weight may be related to this factor, Panteleev noted.

Let us add that the composite allows the wing to work for 100 years or more, without being exposed to water. Thanks to new materials, significant costs for the operational maintenance of composite aircraft are reduced.

Chief Designer of the MC-21 Vitaly Naryshkin noted that the composite wing during testing showed itself without complaints. Aviation expert Roman Gusarov in an interview with «The First Technical» clarified that if winglets are installed on the wing, fuel efficiency may increase.

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• Test pilot appreciated the certification of the MC-21-300 in the import-substituted version