November 10, 2017
JAXA demonstrated effect of airframe noise reduction technologies in a flight test campaign
– the 2nd flight demonstration successfully carried out in September 2017
The FQUROH project team conducted the second flight demonstration on airframe noise reduction technologies with JAXA’s jet research aircraft “Hisho” at Noto Satoyama Airport (Ishikawa, Japan) between 13 September and 1 October 2017. Following the first flight demonstration in 2016 to establish process for flight tests and to evaluate preliminary noise reduction designs, the team carried out this second flight demonstration to verify the final noise reduction designs for “Hisho”. The FQUROH project team successfully performed flyover noise source measurements for 222 times in total with 17 flights of “Hisho”, and obtained all the data necessary for technology verifications.
The aircraft was modified on its flap and main landing gear with further optimized noise reduction designs from the first flight demonstration. The project focuses on noise reduction of flap (or high-lift device) noise and landing gear noise which are the major sources of aircraft noise during approach to airports. It is very important to measure these noise sources in real flight environment with actual aircraft to verify effect and practicability of the noise reduction technologies.
Preliminary results clearly show the effects of the noise reduction designs. The obtained noise reduction in overall level※ is 3dB for the flaps and 4dB for the main landing gear at the moment when the aircraft just fly over the measurement point, which is consistent with the applied noise reduction designs. These airframe noise reduction technologies to be established through the project could lead to overall noise reduction of 4dB for whole aircraft when applied to newly developed aircraft in the future.
Comparison of noise source maps (preliminary results)
The FQUROH project team continues carrying out further analysis of the obtained data more in details. In parallel, the team starts preparation for the flight demonstration with Mitsubishi Regional Jet (MRJ), which is the final phase of the project to establish the noise reduction technologies for civil transport aircraft.
JAXA intends to transfer accomplished technologies to aircraft industries including three industrial partners of the project (Aerospace Company of Kawasaki Heavy Industries, Ltd., Sumitomo Precision Products Co., Ltd., Mitsubishi Aircraft Corporation) with hope to realize quieter aircraft in the future.
- ※ Overall (sound pressure) level:
- Total sound pressure level (SPL) that adds up levels of all frequency bands. Note that the SPLs in the figures are levels in 630 Hz and 1 kHz frequency bands.