著者
溝口 誠 山口 裕
出版者
一般社団法人 日本航空宇宙学会
雑誌
日本航空宇宙学会論文集 (ISSN:13446460)
巻号頁・発行日
vol.60, no.3, pp.121-127, 2012 (Released:2012-10-23)
参考文献数
15
被引用文献数
2 3

The effect of aspect ratio (AR) on the aerodynamic characteristics of rectangular wings is investigated. Reynolds numbers considered are 7.6×104 and 5.2×104. Experimental results are compared with analytical ones obtained from Lamar's method. It is shown that the aspect ratio of wings affects the stall characteristics when AR≤2.0. The aspect ratio also has an effect on the lift slope if AR≤1.5. Furthermore, maximum lift coefficients increase when AR≤1.0. Comparisons show that the variations of aerodynamic characteristics are caused by tip vortices. It is also considered that the position of the center of pressure is varied with the angle of attack because of the effects of the laminar separation bubble and tip vortices on wing surfaces.
著者
小沢 宏臣
出版者
一般社団法人 日本航空宇宙学会
雑誌
日本航空宇宙学会誌 (ISSN:00214663)
巻号頁・発行日
vol.39, no.448, pp.210-217, 1991-05-05 (Released:2010-12-16)
参考文献数
6
著者
MURUGANANDAN Vishnu Anand PARK Ji Hyun LEE Sangyoon JEUNG In-Seuck KIM Sangkyun JU Gwanghyeok
出版者
一般社団法人 日本航空宇宙学会
雑誌
TRANSACTIONS OF THE JAPAN SOCIETY FOR AERONAUTICAL AND SPACE SCIENCES (ISSN:05493811)
巻号頁・発行日
vol.60, no.6, pp.355-365, 2017
被引用文献数
5

The second-generation star tracker estimates pointing knowledge of a satellite without a-priori knowledge. But star trackers are larger in size, heavier, power hungry and expensive for nanosatellite missions. The Arcsecond Pico Star Tracker (APST) is designed based on the limitations of nanosatellites and estimated to provide pointing knowledge in an arcsecond. The APST will be used on the SNUSAT-2, Earth-observing nanosatellite. This paper describes the requirements of APST, trade-off for the selection of image sensor, optics, and baffle design. In addition, a survey of algorithms for star trackers and a comparison of the specifications of APST with other Pico star trackers are detailed. The field of view (FOV) estimation shows that 17° and 22° are suitable for APST and this reduces stray light problems. To achieve the 100% sky coverage, the FOV of 17° and 22° should able to detect the 5.85 and 5.35 visual magnitude of stars, respectively. It is validated by estimating the signal to noise ratio of APST and night sky test results. The maximum earth stray light angle is estimated to be 68° and a miniaturized baffle is designed with the exclusion angle of 27°.
著者
齋藤 英文
出版者
一般社団法人 日本航空宇宙学会
雑誌
日本航空宇宙学会誌 (ISSN:00214663)
巻号頁・発行日
vol.63, no.2, pp.35-37, 2015

Boeing787で本格的な実用化時代を迎えたMEAの将来について,MEAAPの研究会活動を通じて検討を重ねてきた.短時間使用のエンジンスタータを除けば,航空機装備システムの中で最大の電力消費者であるECSは,エネルギ消費に課題があると認識し,ECSが発揮すべき機能に基づいて,エネルギ消費改善の方法を検討している.ECSは,与圧・換気・温度調節という3つの機能が求められるが,構成するサブシステムがこれらの機能を最適に担う形態を追求すると,冷却時のエネルギ利用効率の大幅改善のために,ACSをVCSに置き換える技術獲得が重要であるとの結論に至った.ACSを代替するVCSとして,具体的に実現するための課題を明確にし,課題解決に向けた研究を進めている.併せて,電力量の増大に伴う電力制御機器の冷却は,ユーザでの保守作業改善のために液冷を廃することが望ましい.そこで,新たな冷却方法であるAACS方式を提案し,その検討を進めている.これらについて,解説する.
著者
横山 大知 原田 明徳
出版者
一般社団法人 日本航空宇宙学会
雑誌
航空宇宙技術 (ISSN:18840477)
巻号頁・発行日
vol.20, pp.154-165, 2021 (Released:2021-12-08)
参考文献数
25

Accurate and reliable flight data is indispensable for research and development to explore new findings which will be of assistance in establishing a new system of air traffic management (ATM). Although radar data called CARATS Open Data and Automatic Dependent Surveillance Broadcast (ADS-B) data are currently available, these data have limitations in accuracy and number of parameters; therefore, they are not so sufficient for the research in which detailed parameters such as airdata, take-off weight and cost index are required. The purpose of this study is to verify whether commercially available flight simulator software: X-Plane in which function of Flight Management System (FMS) is replicated, is usable for studies on ATM. To validate whether the flight simulator software can reproduce accurate flight profiles and aircraft parameters, mimicked flight data gained by the simulator is compared with calculated data and real data. In the flight simulation by X-Plane, weather data is input by a piece of software, FS Global Real Weather (FSGRW) which provides the simulator with weather data from National Ocean and Atmospheric Administration's (NOAA) server every 5 minutes.
著者
小平 信彦
出版者
一般社団法人 日本航空宇宙学会
雑誌
日本航空宇宙学会誌 (ISSN:00214663)
巻号頁・発行日
vol.26, no.298, pp.552-557, 1978-11-05 (Released:2009-07-09)
参考文献数
6
著者
榊 和樹 舩橋 友和 中谷 辰爾 津江 光洋 金井 竜一朗 鈴木 恭兵 稲川 貴大 平岩 徹夫
出版者
一般社団法人 日本航空宇宙学会
雑誌
日本航空宇宙学会論文集 (ISSN:13446460)
巻号頁・発行日
vol.65, no.5, pp.193-199, 2017

The longitudinal combustion instability characteristics of a pintle-type injector for a bipropellant rocket engine combustor are investigated experimentally. An optically accessible combustion chamber are used to observe unsteady combustion behaviors under oscillating combustion conditions. CH* chemiluminescence and backlit spray images are observed simultaneously with two high-speed cameras. Two experiments with the propellant total momentum ratio (TMR) of 0.76 and 2.48 are conducted, whereas the combustion pressure and the propellant mixture ratio are 0.45 and 1.6, respectively. The combustion oscillations at the natural frequencies of the chamber longitudinal acoustic mode are observed when the TMR is 0.76. The combustion oscillation is caused by the coupling between the heat release and the combustion chamber acoustics. When the TMR is 2.48, the combustion oscillations at the frequencies of 400 and 800Hz, which are lower than the first longitudinal mode frequency, are observed. Since the 400Hz corresponds to the convective time scale in the combustion chamber, the oscillations could be caused by one of the convective modes such as entropy wave.
著者
角銅 洋実 榊 和樹 中谷 辰爾 津江 光洋 金井 竜一郎 稲川 貴大 平岩 徹夫
出版者
一般社団法人 日本航空宇宙学会
雑誌
日本航空宇宙学会論文集 (ISSN:13446460)
巻号頁・発行日
vol.65, no.1, pp.1-9, 2017

The pintle injector is a promising candidate for injection systems of future rocket engines because of the throttling capability, the combustion stability, and the low manufacturing cost. Few studies focusing on fundamental aspects of a pintle injector have been conducted, and most of the design parameters of a pintle injector is determined mainly based on the empirical knowledge. Among the design parameters, total momentum ratio (TMR) is one of the most important parameters since spray structure is dominated by TMR. Therefore, combustion experiments using an ethanol/liquid oxygen rocket engine combustor with a planar pintle-type injector which is designed for optical measurements for a pintle injector are conducted at combustion pressure (<I>P<sub>c</sub></I>) = 0.37-0.42MPa, mixture ratio (O/F) = 1.31-1.49, TMR = 0.32-3.65 to investigate the effects of propellant momentum ratio on the combustion behavior. The spray structure under hot fire conditions is observed using high-speed imaging techniques with a backlit configuration. In the oxidizer-centered configuration, the characteristic exhaust velocity efficiency (<I>η<SUB>C</SUB><SUP>*</SUP></I>) decreases with the increase of the TMR. The atomized propellant impinge on the combustor wall before the vaporization and reaction at higher TMR. In the fuel-centered configuration, though the propellant spray is more inclined to the direction of the upper combustor wall at higher TMR, the <I>η<SUB>C</SUB><SUP>*</SUP></I> does not change with the TMR. In both oxidizer-centered and fuel-centered, higher <I>η<SUB>C</SUB><SUP>*</SUP></I> is provided in the condition of higher injection pressure drop.