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The Analysis of the Sounds Emitted by Aircraft.
https://jaxa.repo.nii.ac.jp/records/35324
https://jaxa.repo.nii.ac.jp/records/35324bbde598c-c6cf-4500-927a-3031a147b956
| 名前 / ファイル | ライセンス | アクション |
|---|---|---|
SA4146499.pdf (6.6 MB)
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| Item type | 紀要論文 / Departmental Bulletin Paper(1) | |||||||||
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| 公開日 | 2015-03-26 | |||||||||
| タイトル | ||||||||||
| タイトル | The Analysis of the Sounds Emitted by Aircraft. | |||||||||
| 言語 | en | |||||||||
| 言語 | ||||||||||
| 言語 | eng | |||||||||
| 資源タイプ | ||||||||||
| 資源タイプ識別子 | http://purl.org/coar/resource_type/c_6501 | |||||||||
| 資源タイプ | departmental bulletin paper | |||||||||
| 著者 |
OBATA, Juichi
× OBATA, Juichi
× YOSIDA, Yahei
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| 出版者 | ||||||||||
| 出版者 | 東京帝國大學航空研究所 | |||||||||
| 出版者（英） | ||||||||||
| 出版者 | Aeronautical Research Institute, Tokyo Imperial University | |||||||||
| 書誌情報 |
東京帝國大學航空研究所報告 en : Report of Aeronautical Research Institute, Tokyo Imperial University 巻 5, 号 59, p. 144-185, 発行日 1930-03 |
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| 抄録（英） | ||||||||||
| 内容記述タイプ | Other | |||||||||
| 内容記述 | The investigations described herein were undertaken to study the sounds emitted by aircraft in the hope of obtaining fresh light on their nature. The procedure was entirely of objective, namely the sounds were recorded as accurately as possible by means of an electrical arrangement and the analysis were carried out upon the records. The recording arrangement consisted of a band-microphone, seven-stage resistance-capacity-coupled amplifier and an oscillograph. The aircraft, of which the sounds were recorded, were a bomber, chaser, reconnaissance machine and a small dirigible. Straight line flights as well as vertical turns were made. Besides the sounds emitted by an aeroplane in flight, experiments were also made upon an aeroplane on the ground, with special reference to the directivity of the sound and to the influence of the number of revolution on the nature of the sound. The chief sources of the sound of an aircraft are known to be the revolving airscrew and engine-exhaust. The pitches of the fundamentals of these sounds are given by: N_p: (number of blades)×1/60×(r. p. m.)×(reduction gear ratio) and N_e: (number of cylinders)×1/60×1/2(r. p. m.), respectively. The correspondence of the pitches of the recorded sounds to these values were studied in all cases. In general, the sounds of aircraft are of very complex nature, overtones than the fundamentals being predominant in most cases. At long distance the greater part of the sound originates from the propeller, and it mainly consists of the fundamental and second harmonics, i.e. N_p and 2×N_p, while at short distance the exhaust-sound predominates. Different aeroplanes equipped with same kind of engine gave quite different records of sound. On the other hand, a bomber with a Napier-Lion 12-cylinder engine often showed a component having a pitch 1/3 of the fundamentals above mentioned, which is undoubtedly due to the fact that the cylinders are arranged in three different banks. In the case of a chaser equipped with a Hispano 8-cylinder engine a component having a pitch 1/2 of the fundamental was sometimes observed. Therefore, in calculating the pitch of the fundamental of the exhaust-sound it is much more appropriate to use the number of cylinders per bank, instead of the total number of cylinders. Several examples were obtained, which show the existence of the particular tone pointed out by Prof. L. Prandtl, consisting of only two impulses, i.e. the direct impulse and that reflected from the ground. | |||||||||
| 書誌レコードID | ||||||||||
| 収録物識別子タイプ | NCID | |||||||||
| 収録物識別子 | AA00387631 | |||||||||
| 資料番号 | ||||||||||
| 内容記述タイプ | Other | |||||||||
| 内容記述 | 資料番号: SA4146499000 | |||||||||
