著者
國中 均 西山 和孝 清水 幸夫 都木 恭一郎 川口 淳一郎 上杉 邦憲
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.52, no.602, pp.129-134, 2004 (Released:2004-05-20)
参考文献数
11
被引用文献数
5 or 0

The microwave discharge ion engine generates plasmas of the main ion source as well as the neutralizer using 4GHz microwave without discharge electrodes and hollow cathodes, so that long life and durability against oxygen and air are expected. MUSES-C “HAYABUSA” spacecraft installing four microwave discharge ion engines was launched into deep space by M-V rocket on May 9, 2003. After vacuum exposure and several runs of baking for reduction of residual gas the ion engine system established the continuous acceleration of the spacecraft toward an asteroid. The Doppler shift measurement of the communication microwave revealed the performance of ion engines, which is 8mN thrust force for a single unit with 3,200sec specific impulse at 23mN/kW thrust power ratio. At the beginning of December 2003 the accumulated operational time exceeded 7,000 hours and units.
著者
安田 邦男
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.47, no.547, pp.314-320, 1999-08-05 (Released:2009-07-09)
参考文献数
7
被引用文献数
1 or 0

A wind tunnel test was conducted to study the mechanism of a flight of a flying disc which flies while rotating. A Flying disc is a rotating disc without blades, being different from the rotor of a helicopter and the like and its cross sectional shape is a unique upward convex. Using a production flying disc used at an official game, wind tunnel tests were performed. Forces were measured to investigate aerodynamic characteristics of an object of such a shape. In addition, a flat disc was also experimented for a comparison. Free flight tests of the flying disc were carried out to obtain base line data to experiment in the wind tunnel test. Flight data of the flying disc in free air was reduced by analyzing the flight path from the video tapes which recorded the flights of the flying disc. Smoke visualization tests were also made to visualize the flow pattern around the flying disc.
著者
永井 俊一 大竹 智久 本橋 龍郎
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.56, no.656, pp.442-448, 2008 (Released:2008-09-25)
参考文献数
8

We studied effect of ventilation ports on aerodynamics of the fuselage of a human-powered airplane and cooling performance of the pilot. An opening made in the fuselage is one of remedies for enhancing the performance of the pilot. On the other hand, the opening influences aerodynamic characteristics of the airplane, in particular the drag of the fuselage. When the ratio of inlet and outlet areas is larger than 3.0, the flux of air taken at the inlet is almost proportional to the area of inlet and depends weakly on the position and area of the outlet. Cooling of the pilot is estimated from the data of Nusselt number around the cylinder in the uniform flow at the Reynolds number defined by a velocity averaged over a cross section. An additive drag due to interaction between the injected flow from the outlets and the ambient flow around the fuselage depends strongly on the location of the outlet; the nearer to the trailing edge the outlet position moves, the less the drag increases.
著者
林 健太郎 麻生 茂
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.52, no.600, pp.38-44, 2004 (Released:2004-02-19)
参考文献数
18
被引用文献数
2 or 0

An experimental study on reduction of aerodynamic heating due to opposing jet in supersonic flow has been conducted. Experiments are conducted by using a conventional blowdown type wind tunnel. A hemisphere model is installed into supersonic free stream of Mach number of 4 and coolant gas is injected through a sonic nozzle at the top of the model. Significant decrease of surface heat flux distribution is observed and opposing jet is proved to be quite effective on the reduction of aerodynamic heating at the nose region of the blunt body. The effect of total pressure ratio of opposing jet to the free stream on the reduction of aerodynamic heating is also investigated.
著者
渡邉 力夫 林 浩平 岩尾 正樹 井河 恵大 冨田 信之
出版者
一般社団法人 日本航空宇宙学会
雑誌
宇宙技術 (ISSN:13473832)
巻号頁・発行日
vol.7, pp.45-52, 2008 (Released:2008-10-11)
参考文献数
9

When liquid nitrogen and heated water are mixed in a chamber, pressure increase due to evaporation expansion inside the chamber becomes high enough to generate thrust force for rocket propulsion. This thrust system is safer and environment-friendly compared to conventional rocket engines utilizing combustion process. This new type of rocket engine system is called "Water-Liquid Nitrogen rocket engine system" and it can be used for small payload mission with expected altitude of several kilometers. In this paper, experimentally obtained thrust characteristics are shown and analyzed. As a result, relations between the thrust force and the mixing chamber pressure are clarified. Also, it is found that the present injector can attain only half of the theoretically expected specific impulse due to insufficient mixing efficiency.