21st Congress of International Council of the Aeronautical Sciences, Melbourne, Australia, 13-18 September, 1998
Paper ICAS-98-6.4.3

DEVELOPMENT OF AN INTEGRATED CONCEPTUAL AIRCRAFT DESIGN AND AIRCRAFT NOISE MODEL FOR CIVIL TRANSPORT AIRCRAFT

Caves R. E., Jenkinson L. R., Rhodes D. P.
UK Civil Aviation Authority, United Kingdom

Keywords: conceptual aircraft design, aircraft noise model, civil transport aircraft

Recently environmental factors, such as noise and emissions have begun to a play significant role in the design of new aircraft. Although advances in propulsion technology have reduced source noise levels significantly over the past few decades, it is becoming increasingly difficult to project similar advances for the next few decades. It is likely however that some noise benefits may come from improvements in aircraft performance and from changes in operational procedures. In order for such developments to be analysed at the conceptual design stage, an integrated conceptual aircraft design and aircraft noise model is required that enables the designer to rapidly asses the effect of key design parameters on reference noise levels and noise contour area. The paper describes the integration of a conceptual design model and integration with the NASA Aircraft Noise Prediction Program (ANOPP). The completed model is applicable to civil transport aircraft with high bypass ratio turbofan engines and was validated using the Boeing 757 and Boeing 747 aircraft at the key certification reference points. Model agreement is shown to be good, particularly in terms of aircraft design and performance characteristics. Accuracy of noise prediction was also encouraging once the data was corrected to account for acoustic treatment of the engine nacelle, a feature present on both of the validation aircraft. The integrated model is then applied in two aircraft design scenarios. The first study shows the effect of changing the thrust/weight ratio on take-off flyover noise levels is analysed. The second study investigates the sensitivity of approach angle to approach noise levels. Results illustrated in the paper show that increasing height during the approach phase can significantly reduce approach noise, provided some increases in descent rate during approach are acceptable.

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