INFLUENCE OF POWER UNIT CONFIGURATION LAYOUT OF A REGIONAL JET ON PERFORMANCE AND DIRECT OPERATING COST

摘要

The motivation for this research work comes from the HELENA project and the later initiative of 4 central European countries devoted to the creation of modern European Regional Aircraft. The paper presents a configuration of a significantly lower noise, emission, top-class operational economy, highly increased safety level, extra ordinary cabin comfort and reduced boarding time. Aircraft is powered by one external engine, selected for cruise conditions and supplemented by another internally located engine, used mainly for take-off and emergency. Both engines are located in the rear part of aircraft, in its plane of symmetry which is beneficial when one of the engines is non-operational. Every engine can maintain a steady level flight and safe landing if the other unit fails. The reason for big improvement of flight economy, numerically proved in this paper, did not come from aerodynamic drag reduction, but mainly from much better performance of the selected cruising engines. Larger turbofans are usually more fuel efficient because of more advanced technologies used and the characteristics of the phenomena occurring inside the engines. Specific fuel consumption for turbofans used in research variants of the airplane is respectively 19.65 % and 31.12 % lower than for CF-34-8E, which is very similar to final profits. The most likely percent of fuel consumption reduction that can be achieved is between these two values received from performed calculations.