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 6

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 2

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
長谷川 裕晃 北原 一起 犬飼 保夫
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.50, no.582, pp.272-272, 2002 (Released:2003-09-02)
参考文献数
5
被引用文献数
2 1

The Air Turbo Ramjet (ATR) is a combined cycle engine which performs like a turbojet engine at subsonic speeds and a ramjet at supersonic speeds and therefore the ATR is an attractive propulsion system for the wide operation range (e.g. Mach 0 to Mach 4). The ATR can provide a higher specific impulse than a solid fuel rocket engine and a higher thrust per frontal area than a turbojet engine. The major ATR components are the inlet, fan (compressor), turbine, gas generator, combustor and exhaust nozzle. In the ATR, the turbine drive gas is generated by a decomposed liquid or solid fuel gas generator. In order to carry heavier payloads and to attain shorter flight time, the compact and high thrust engine is required. In this study, the ram combustor with the double-staged flameholders and the fan with tandem blade were introduced to shorten the engine length and to increase the fan pressure ratio, respectively. Furthermore, the engine testing was carried out on sea level static condition to confirm the engine component integration technologies for the ATR propulsion system.
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 3

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
沢田 雅洋 山下 博 岩崎 俊樹 大林 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.58, no.681, pp.295-301, 2010 (Released:2010-10-27)
参考文献数
14

Research of Long-Distance Human-Powered Flight has been performed through the following four items: Aircraft design, Risk management, Pilot performance, Weather prediction. Actual flight took place on August 12, 2009. The flight distance was 20.72km. In this study, results of weather prediction using 1-way downscaling technique are validated by surface observation data and feasibility of weather prediction for Long-Distance Human-Powered Flight is discussed. The weather prediction with 1-km mesh decreases RMSE of wind speed by 0.1--0.2m/s compared with that with 5-km mesh. The weather prediction with 1-km mesh also has a potential to reproduce nonstationary wind. The RMSE gradually increase with time, which is mainly caused by initial and boundary data given from coarse mesh model. To reduce the RMSE, it is desirable to use newest analysis data as possible for initial and boundary data.
著者
渡辺 力夫 冨田 信之 竹前 俊昭
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.51, no.593, pp.314-320, 2003 (Released:2003-09-26)
参考文献数
17
被引用文献数
2 2

The propulsive characteristics of water rockets are analyzed theoretically and experimentally. The unsteady thrust force acting on a PET bottle and the air pressure inside the bottle are measured simultaneously by the thrust test stand we have developed. The semi-empirical thrust history is obtained utilizing the air pressure history and it is compared with the measured thrust history. The results show qualitative agreement. The observation of the flow inside bottle by a high-speed video camera shows that the air precedes water when it is about to be discharged entirely. We have developed a flow regulator attached to the nozzle cap to reduce the precursor air discharge that is considered as a result of the swirling flow inside the bottle. The experimental results show that the air discharge and the body vibration are suppressed effectively.
著者
大津 広敬 安部 隆士 船木 一幸
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.54, no.628, pp.181-188, 2006 (Released:2006-06-30)
参考文献数
17
被引用文献数
2 2

An applicability of the electrodynamic heat shield system to super-orbital reentry vehicles was investigated. In the case of the super-orbital reentry flight, due to the strong ionization reactions inside the shock layer, the heat shield system which utilizes the electromagnetic force is expected to work well. In the present study, in order to evaluate the reentry heating reduction by this heat shield system, we performed a CFD analysis including thermochemical non-equilibrium effects and an electromagnetic force. The flight condition used for the present study is that the velocity is 11.6km/s at the altitude of 64km at which the stagnation point heat flux of the MUSES-C reentry capsule is considered to be the maximum value. From our CFD results, we found that the heat flux to the vehicle could be reduced by up to 50%. Additionally, it was also found that the drag coefficient increased with the magnetic field strength, and the maximum value of the drag coefficient was 2.0 with the magnetic field strength of 0.6[T].
著者
伊藤 隆 宮島 博
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.53, no.619, pp.351-357, 2005 (Released:2005-11-09)
参考文献数
16
被引用文献数
2 2

Performance of the methane fueled rocket nozzles are numerically investigated using computational fluid dynamics approach. A simple set of chemical reactions and kinetics for methane/oxygen nozzle flow is proposed. The chamber pressure, mixture ratio and size of the nozzle are parametrically changed to study the influence of characteristic rocket engine design parameters on nozzle losses. The amount of dissociation is high when the chamber pressure is low and the kinetic loss becomes dominant compared to the other nozzle losses. The peak specific impulse is achieved at a higher mixture ratio region as the chamber pressure increases. The chemical non-equilibrium flow appears mainly at down stream region of the nozzle throat. The influence of the chemical non-equilibrium effect decreases as the chamber pressure increases. Supersonic chemically reactive gas stays longer in the nozzle as the size of the nozzle become larger and the amount of recombination increases which decreases the kinetic loss. When the chamber pressure is high, the kinetic loss becomes small and the effect of the size of nozzle also becomes small.
著者
河野 功 杢野 正明 鈴木 孝 小山 浩 功刀 信
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.49, no.575, pp.432-437, 2001 (Released:2002-04-26)
参考文献数
6
被引用文献数
2 2

Engineering Test Satellite-VII (ETS-VII) is a test satellite to perform in-orbit demonstration of autonomous rendezvous docking (RVD) technology, which will be necessary for advanced space activities in the early 21st century. ETS-VII successfully performed the autonomous RVD by unmanned space vehicle for the first time in the world. For an unmanned space vehicle to perform rendezvous to a manned spacecraft, safe approach is needed. So we paid special attention to designing safe approach trajectory. There are other important points for approach trajectory design, for instance, coordination with guidance and control accuracy, performance of navigation sensors, and operability, etc. In this paper, we introduce the points, and show the result of ETS-VII RVD trajectory design.
著者
渡辺 力夫 冨田 信之 竹前 俊昭
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.609, pp.449-455, 2004 (Released:2004-11-30)
参考文献数
12
被引用文献数
1

The aerodynamic characteristics of water rockets are analyzed experimentally by wind tunnel testing. Aerodynamic devices such as vortex generators and dimples are tested and their effectiveness to the flight performance of water rocket is discussed. Attaching vortex generators suppresses the unsteady body fluttering. Dimpling the nose reduces the drag coefficient in high angles of attack. Robust design approach is applied to water rocket design for flight stability and optimum water rocket configuration is determined. Semi-sphere nose is found to be effective for flight stability and it is desirable for the safety of landing point. Stiffed fin attachment is required for fins to work properly as aerodynamic device and it enhances the flight stability of water rockets.
著者
吉川 俊明 坂本 慎介 堀 琴乃 楠本 寛 山本 康 服部 高資 佐多 宏太
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.655, pp.391-395, 2008 (Released:2008-08-27)
参考文献数
7
被引用文献数
1 1

In this paper, we propose the method for the measurement of required power and the adjustment of optimum gear ratio in take-off ground running. To get the values of required power and speed, we measured torque of the left side and the right side of pedals, RPM of pedals, and speed of the cockpit frame. In order to improve the take-off speed, some drums were applied, and the optimum gear ratio of the front drum to the rear drum was determined.
著者
小松 敬治 佐野 政明 角田 義秋
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.51, no.591, pp.158-163, 2003 (Released:2003-09-16)
参考文献数
10
被引用文献数
3 3

Progress in materials technology has produced a much more durable synthetic fabric envelope for the non-rigid airship. Flexible materials are required to form airship envelopes, ballonets, load curtains, gas bags and covering rigid structures. Polybenzoxazole fiber (Zylon) and polyalirate fiber (Vectran) show high specific tensile strength, so that we developed membrane using these high specific tensile strength fibers as a load carrier. The main material developed is a Zylon or Vectran load carrier sealed internally with a polyurethane bonded inner gas retention film (EVOH). The external surface provides weather protecting with, for instance, a titanium oxide integrated polyurethane or Tedlar film. The mechanical test results show that tensile strength 1,000 N/cm is attained with weight less than 230g/m2. In addition to the mechanical properties, temperature dependence of the joint strength and solar absorptivity and emissivity of the surface are measured.
著者
河原 淳人 岩堀 太紀 山川 宏 佐藤 亨 山本 衛 橋口 浩之
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.64, no.3, pp.189-199, 2016 (Released:2016-06-05)
参考文献数
18

Shape estimation of space debris is an important task in evaluating its trajectory evolution and collision probability with resident objects in space. This paper shows the magnitude and rotation of space debris can be estimated by investigating the Doppler shift with a Single Range Doppler Interferometry (SRDI) method. The theory of SRDI method is discussed and its usefulness is confirmed by numerical simulations. Furthermore, fluctuation of Doppler shift of known space debris were successfully observed by the MU radar of Kyoto University and the size and spin rate of some space debris were successfully estimated.
著者
杉浦 綾 横関 智弘 平野 義鎭
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.61, no.5, pp.133-140, 2013 (Released:2013-10-25)
参考文献数
24

This paper describes the development and the wind tunnel test of a variable geometry morphing airfoil using corrugated structures. Feasibility of a morphing wing with corrugated flexible seamless flap-like structure is verified by the finite element analysis, and a prototype is manufactured using carbon fiber reinforced plastics. For the actuation system, two servomotors are installed inside the prototype wing to control the airfoil shape by the chord-wise tension of the connected wires. Successful actuation of the prototype wing is demonstrated under the air speed up to 30m/s in the wind tunnel test. Basic aerodynamic properties are also evaluated in comparison to traditional airfoil with a hinged control surface. Lift increase of variable corrugated wing is recognized when the flap angle increases.
著者
元田 敏和
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.55, no.638, pp.117-124, 2007 (Released:2007-04-20)
参考文献数
15

In aerospace projects preflight evaluation is crucial for mission success, because flight testing in a real environment is often difficult or impossible. Monte Carlo simulation is a powerful tool for the preflight evaluation because a nonlinear system incorporating various uncertain parameters can be evaluated directly. Monte Carlo simulation has been used in various aerospace projects throughout the world as the computer power increases. After the system evaluation, it is important to detect influential uncertain parameters which cause significant performance degradation so that measures for the system improvement can be studied. However, detecting those parameters is often uneasy because various uncertain parameters are incorporated simultaneously and their magnitudes are randomly generated in Monte Carlo simulation. An interaction of more than two uncertain parameters might be affected. This paper presents a simple approach to detect influential uncertain parameters applying a statistical test to the Monte Carlo results.
著者
峯岸 正勝 熊倉 郁夫 岩崎 和夫 少路 宏和 吉本 周生 寺田 博之 指熊 裕史 磯江 暁 山岡 俊洋 片山 範明 林 徹 赤楚 哲也
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.51, no.594, pp.354-363, 2003 (Released:2003-09-26)
参考文献数
19
被引用文献数
1 1

The Structures and Materials Research Center of the National Aerospace Laboratory of Japan (NAL) and Kawasaki Heavy Industories, Ltd. (KHI) conducted a vertical drop test of a fuselage section cut from a NAMIC YS-11 transport airplane at NAL vertical drop test facility in December 2001. The main objectives of this program were to obtain background data for aircraft cabin safety by drop test of a full-scale fuselage section and to develop computational method for crash simulation. The test article including seats and anthropomorphic test dummies was dropped to a rigid impact surface at a velocity of 6.1 m/s (20 ft/s). The test condition and result were considered to be severe but potentially survivable. A finite element model of this test article was also developed using the explicit nonlinear transient-dynamic analysis code, LS-DYNA3D. An outline of analytical method and comparison of analysis result with drop test data are presented in this paper.
著者
中谷 辰爾 笠原 希仁 芝 世弐 大坂 淳 津江 光洋 河野 通方
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.610, pp.487-493, 2004 (Released:2005-01-05)
参考文献数
46

Numerical analysis of O3 depletions by exhaust plume from stratospheric flight at the altitude of 25km was conducted. Expanding box method was employed to simulate a diffusion of exhaust plume in the stratosphere. Concentrations of chemical species and normarized sensitivities of O3 concentration for reactions were estimated by fifth-order BDF method. Chemical kinetics include NOx, HOx and Ox chemistry. As results, it takes over two days that O3 concentration within a plume becomes ambient lebel within 1ppb. O3 perturbations were changed by an effect of plume-emission time, and they are bigger in daytime than in nighttime. Distributions of sensitivities of O3 concentrations for reactions are also changed for the plume-emission time. O3 depletion is greater by NOx than by HOx in exhaust plume.
著者
平田 邦夫 上條 謙二郎 升谷 五郎
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.53, no.614, pp.123-129, 2005 (Released:2005-05-20)
参考文献数
3

Idle spin phenomena were observed at rapid transient phase in liquid hydrogen pumps for rocket engines. Failure analyses were conducted and evaluation equations to estimate the shift of the operation point of the pump were derived in this paper. It was revealed that rapid fall of hydrogen flow rate resulted in decrease of pump efficiency which caused excessive temperature rise up to the saturation of the pump fluid.
著者
太田 貴之 梅村 章
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.49, no.574, pp.382-387, 2001 (Released:2002-04-26)
参考文献数
8
被引用文献数
3 2

Parametric study is conducted to find the optimum condition of water rocket for long flight, provided that the tank volume is prescribed. The parameters considered in the present study are the initial air pressure, water volume fraction, empty rocket mass, launching angle and bottle diameter which significantly affect the flight performance of water rocket. First, we calculate the temporal changes in tank pressure, water and air issue speeds and thrust, on the basis of a simple physical model which has been experimentally validated. Then, this model is incorporated into the equation of motion to calculate the ballistic flight of water rocket with various parameter values. As a result, it is found that PET bottles in the market are one of the most suitable for use as the pressure tank of water rocket.