In the Air

Piotr Butowski reports on the first flight of the Irkut MC-21, Russia’s latest airliner

On the morning of May 28, at the Irkut Corporation airfield in Irkutsk near Lake Baikal, the first new MC-21- 300 airliner, registered 73051 (c/n 0001), took off. The aircraft, with Oleg Kononenko and Roman Taskayev at the controls, spent 30 minutes in the air. The flight was made without problems at a speed of 162kts (300km/h) and at an altitude of 3,281ft (1,000m). The MC-21 was accompanied in flight by a Yak-130 jet trainer, which is also made in Irkutsk.

The President of Irkut Corporation, Oleg Demchenko, declared: “Today is a historic day for our collective and the whole command working on [the] MC-21. We have applied in our aircraft the most advanced technical solutions, which will provide increased comfort to passengers and attractive efficiency features to airlines.”

The beginning of MC-21 testing, previously declared for the beginning of this year, was moved back several times. At the end of February 2017 during strength testing at the TsAGI institute in Zhukovsky, at a loading of 96% of design value, cracks on the MC-21’s composite wing torsion box appeared. According to Irkut, the necessary reinforcement of the wing, also applied to the first flight prototype, has increased weight by 25kg (55lb) and delayed testing for a month.

On April 28, the MC-21 was rolled out on the airfield and direct preparation for flights began. In the middle of May, the aircraft undertook the first speed taxiing. The first meeting at the European Aviation Safety Agency’s Cologne, Germany, headquarters on April 19–21, 2017, where the Russians presented the MC-21 and plans for its certification in Russia and then in Europe, was an important event for the programme.

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The flight test crew for the first MC-21 flight: Oleg Kononenko (left) and Roman Taskayev.
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This angle shows the high aspect ratio wing, which is made of composites processed in a new technology called vacuum infusion.

Technologies

The MC-21, or Mainline Aircraft for the 21st century, is to be a breakthrough product. The Russians understand the MC-21 must be significantly better than its rivals to succeed. To fulfil this aim, they developed an entirely new wing with a high aspect ratio of 11.5, creating a high lift-to-drag ratio. At Mach 0.8, the MC-21’s lift-to-drag ratio is claimed to be 6% better than that of the Airbus A320 and 7% better than the Boeing 737NG.

The wing is made of composites processed in a new technology called vacuum infusion, previously never used in the aircraft industry for producing such large components. The main advantage of vacuum infusion is the possibility of making large integral structures, like the 18m-long (59ft) and 3m-wide (4ft) MC-21 wing panel, in a single cycle.

The fuselage is of conventional metal construction. However, the MC-21 has a fuselage wider than its rivals; its outer diameter is 4.06m (13ft 4in), 150mm (5.9in) more than that of the A320 and 300mm (11.8in) more than that of the 737. The additional width can be used for wider seats or for a wider aisle. The first option will be liked by passengers and the latter by low-cost operators seeking savings by shortening the turnaround (disembark and embark) time. Passenger comfort is also increased by the new air conditioning system that maintains pressure equivalent to the altitude of 6,000ft (1,800m) instead of the standard 8,000ft (2,500m). The cabin windows are larger than usual.

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The first MC-21-300 flight test aircraft departs Irkutsk on its initial flight.
All photos Irkut Corporation
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The MC-21-300’s maiden flight saw the aircraft attain a speed of 162kts (300km/h) and an altitude of 3,281ft (1,000m).

Irkut selected the Pratt & Whitney PW1400G geared turbofan for the MC-21, which is virtually the same engine as the PW1100G used on the A320neo. The airliner’s first version, the MC-21-300, is powered by two PW1431G engines rated at 31,000lb (137.9kN) on take-off; the later MC-21-200 version will be powered by PW1428G engines rated at 28,000lb (124.5kN).

Simultaneously, the Russians started development of the indigenous PD-14 (Perspektivnyi Dvigatel, future engine, 14 tonnes) intended for the MC-21-300. The PD-14 is a conventional (not geared) twin-spool bypass ratio turbofan with moderate bypass ratio of 8.5:1 (the PW1400G has 12:1). On October 30, 2015, the prototype of the PD-14 was for the first time run in the air on an Il-76LL flying testbed. The PD-14 engines are to be fitted to the first MC-21-300, 73051, by June 30, 2018.

The initial 163-seat (in typical twoclass configuration) MC-21-300 version has collected the most orders and is being developed first; afterwards, a 5.5m (18ft) shorter MC-21-200 for 132 passengers will be developed. These are the only two versions in Irkut’s plans. The final decision about the stretched MC- 21-400 version is not expected soon; market research is still in progress.

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Two Pratt & Whitney PW1431G geared turbofans power the first MC-21-300. Indigenous PD-14 engines are scheduled to be fitted to this aircraft by June 30, 2018.

Development Plans

By the end of this year, the Irkutsk factory is expected to produce a further two flying prototypes of the MC-21- 300, numbers 0003 and 0004. Aircraft 0005 for fatigue testing is to be ready by March 31, 2018. (Airframe 0002 has been used for strength tests in TsAGI since last autumn.)

According to the latest edition of the national Program of Development of the Aircraft Industry for 2013–2025, accepted by the Russian Government on March 31, 2017, the Russian certificate for the aircraft with Pratt & Whitney engines is to be issued by December 30, 2018, and the aircraft with PD-14 engines will be certified by December 30, 2019. The first prototype of the shortened MC-21-200 version is to be made by June 30, 2019.

So far, Irkut has collected 175 firm orders and 110 options and intents of purchase. The launch and largest customer is the Russian state-owned Rostec Corporation, which in August 2011 ordered 35 MC-21-300s and 15 MC-21-200s for Aeroflot, all with PW1400G engines. In April 2017, Aeroflot’s Chief Executive Officer, Vitaly Savelyev, said he expected to receive the first three aircraft in 2019. Among the firm orders for the MC-21 there are no foreign customers. The production rate is scheduled to reach the intended figure of six aircraft per month in 2022.

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In two-class configuration the MC-21-300 will be able to carry 163 passengers and have a range of 3,240 nautical miles (6,000km).

IRKUT MC-21 CHARACTERISTICS

Length: 42.2m (138ft 5in)

Wingspan: 35.9m (117ft 9in)

Height: 11.5m (37ft 9in)

Max take-off weight: 79,250kg (174,716lb)

Max landing weight: 69,100kg (152,339lb)

Max payload: 22,600kg (49,824lb)

Max fuel capacity: 20,400kg (44,974lb)

Passengers: 163 in typical two-class configuration or maximum 211

Range: 3,240 nautical miles (6,000km) in typical two-class configuration

Cruise speed: Mach 0.8