IL-76MD-90А aircraft competitiveness recovery

Аuthors

Komov A. A.

Moscow State Technical University of Civil Aviation, 20, Kronshtadskiy Bulvar, Moscow, 125993, Russia

e-mail: komesk73@yandex.ru

Abstract

The paper compares competitiveness of Il-76MD-90А with the US C-17 military transport aircraft. The basic assessment criterion is the aircraft capability to perform landing on unprepared sites with restricted run length, which requires employing the engine thrust reverse.

The problems under discussion relate to employing thrust reverser of PS-90A-76 engine, installed on the Il-76MD-90А aircraft. These problems do not only increase the cost of an aircraft operating cycle and affect the flight safety, but reduce its competitiveness as well. The paper presents computation and experimental data, revealing that the main cause of the emerging problems consists in poor external aerodynamics of the power plant during an aircraft ground run employing the thrust reverse. By external aerodynamics the authors mean the gas jet discharge type form the engine reverse units, which may interact with the engine itself and control airframe surfaces while its ground run. Such interaction can lead to:

– gas dynamic instability in engine operation;

– damages to the rotor blades of the engine caused by foreign objects thrown from the surface of the aerodrome;

– Aircraft dynamic characteristics deterioration (wind drag, stability, controllability), and aircraft run-length increase. Unsatisfactory external aerodynamics of the Il-76MD-90A aircraft is the cause of its poor competitiveness compared to the US military transport aircraft S-17.

Ways to the aircraft external aerodynamics improvement are considered below:

– the engine reversal thrust value optimization;

– reverse jets discharge optimization in accordance with the aircraft layout.

Ways of the Il-76MD-90A aircraft external aerodynamics improvement were developed based on estimated and full-scale studies. The substantiation of the developed measures is based on the design features analysis of the S-17 engine reverser unit.

From the above said the author concludes:

1. The level of Il-76MD-90A aircraft power plant external aerodynamics is not high enough.

2. The Il-76MD-90A airplane competitiveness recovery requires carrying out studies on the power plant external aerodynamics improvement, which will allow competition with the S-17 aircraft in the foreign market.

Keywords:

the power plant external aerodynamics, thrust reverser, foreign objects, opposite thrust value optimization, reverse jets expiration optimization

References

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