The most important phase of the PD-14 certification programme is to be the flight tests onboard the Gromov Flight Research Institute's (LII) Il-76LL flying testbed, slated for November this year. Aviadvigatel JSC shipped another PD-14 prototype engine, No. 100-07, to LII in late September 2015 following its assembly and tests on an in-house test rig.

An experimental PD-14-based powerplant was being assembled under the left wing of the Il-76LL flying testbed in a hangar at LII in October. "The flying testbed will record the operating parameters of the engine (rpm, pressure and temperature at various parts of the engine, and strength), and assess the performance of the fuel and oil systems and the automatic control system as well," a UEC spokesperson told.

The PD-14's mounting on the flying testbed had been preceded by serious preparation of the aircraft itself by personnel with UEC and United Aircraft Corporation. In particular, the cargo hold was fitted with new working stations for flight test engineers, equipped with computers, monitoring and control equipment for the engine's prototype and aircraft's experimental systems, and the relevant aircraft assemblies and the pylon were made.

A decision was made to use the Il-76LL (side number RA-76529) as flying testbed. The plane was made in 1977 as the baseline-model Il-76 transport and exported, but got back to Russia in the late 1980s and was converted to the flying testbed designed for trying out advanced engines. It was used in 1989 for testing the 10,900 hp D-236T propfan engine prototype with the SV-36 propeller and then the 14,000 hp D-27 prototype with the SV-27 propeller. Later, the aircraft had sat mothballed at LII for a long time, until a new important job for it came up. Th roll-out of the Il-76LL (RA-76529) flying testbed with PD-14 No. 100-07 under its left wing took place on 20 October 2015.

But before it flies, another prototype engine (No. 100-08) has to complete its tests on a high-altitude test bench in Central Institute of Aviation Motors (CIAM). The completion of the engine's assembly by the Perm Engine Company, tests on Aviadvigatel's test rig and the shipping to CIAM were scheduled for October 2015.

The development of the new-generation 12,500-15,600 kgf PD-14 - the first in the family of future engines with a thrust of 9,000-18,000 kgf - by a large team of UEC's subsidiaries with Aviadvigatel as prime contractor is UEC's key advanced commercial aircraft engine programme now.

The PD-14 is a twin-shaft separate-exhaust design with the direct fan drive. All engines in the family have the same gas generator with the eight-stage high-pressure compressor, low-emission annular combustor and two-stage high-pressure turbine. The baseline PD-14 will be fitted with the single-stage fan of 1,900 mm diameter retaining the size of the PS-90A fan, three-stage low-pressure compressor and six-stage low-pressure turbine.

The 14,000 kgf PD-14 baseline model is designed to power the MC-21-300 short/medium-range airliner. The shrinked version, the MC-21-200, is supposed to be powered by 12,500 kgf PD-14A engines, and the 15,600 kgf PD-14M is designed to equip the tentative 'stretch', the MC-21-400, and the future MTA multirole transport aircraft being co-developed by Russian and Indian engineers. According to the estimates, the PD-14 is on a par with its foreign rivals, the PW1400G and LEAP-X, in terms of specific fuel consumption at cruising speed.

UEC is counting on the Interstate Aviation Committee's Aviation Register to issue the PD-14 engine its type certificate in 2017. The prototype MC-21 fitted with a pair of PD-14s is to start flying at the end of the same year.

Published in Take-off magazine, November 2015.

(Photo: Andrey Fomin)