Noise prediction for aircraft during approach is necessary for environmental assessment around airports. This study aims to develop a component-wise sound source model of aircraft during the approach using flight parameters and publicly available aircraft specifications. By using the aircraft specifications as input parameters, different types of aircraft can be described in a single model. The component-wise sound source spectra measured using a phased microphone array are related to the flight data and publicly available aircraft specifications using a neural network to obtain the sound source model. The developed model can predict component-wise sound power spectra, and the variation of the spectra in terms of different flight conditions can be evaluated. The presented model predicts the sound source spectrum with an accuracy of 2–3 dB. Based on the developed sound source model, noise on the ground is calculated with an accuracy of approximately 2 dB.

The development program of the first Korea Electric Unmanned Helicopter (K-EUH) with maximum take-off weight (MTOW) 125 kg, payload 20 kg, flight distance 60 km and flight time 30 min was initiated in 2019 to prepare future eco-environmental VTOL vehicle for urban parcel delivery service and urban air mobility service as a part of national UAM and drone service market promotion in Korea. For this K-EUH program, KARI selected the baseline of unmanned helicopter named as SD-110 helicopter with MTOW 110 kg and gasoline engine. KARI had studied the existing electric helicopter development examples, electric motor for drone and battery system for electric vehicle. In this paper, the general overview for development of Korea electric unmanned helicopter with MTOW 125 kg was described. The main development activities such as design, analysis, fabrication and test were explained in detail. Finally, the flight demonstration was introduced. In this project, KARI have developed key technologies of electric unmanned helicopter such as battery management system, power management system and electric unmanned helicopter vehicle.