An “aircraft” would be useful to do detailed surveys of the surfaces of Mars and Venus. The “aircraft” needs a propulsion engine which can work in the planet atmospheres, mainly consisting of CO2. The purpose of this paper is to assess the feasibility of the CO2-breathing engine using metal fuels for the planet use. The heats of reactions between metals and CO2 were reviewed. Equilibrium compositions and temperatures of the metal-CO2 flames were calculated. It was confirmed experimentally that Al and Mg could burn in CO2. Thermodynamic cycle calculations were carried out to evaluate the performance of a CO2-breathing turbojet engine. With these results, we conclude that it is capable of developing the metal fueled CO2-breathing turbojet engine with a practicable performance.
In the multi-beam satellite communication, accurate on-board antenna pointing control is required, because of narrow beam width. On the other hand pointing errors resident in on-board antennas have the tendency to increase due to manufacturing difficulty caused by enlargement of antenna reflector's size and also the deployment system. These reasons have made it necessary for attitude and antenna drive control systems to be incorporated in an antenna pointing control system. This paper describes system configurations and interface design of an on-board antenna pointing control system for 20/30GHz antenna in 1-ton class geostationary satellites. This control system was designed to satisfy a pointing accuracy requirement of 0.04° (3σ). Also described are the testing methods employed in and the results obtained from ground closed-loop tests of the control system.
Capillary pumped thermal loops are very effective devices as the rejection system of waste heat from artificial satellites and space vehicles, since they can transfer the heat without external power and furthermore they are light weight, highly reliable and long life devices. They are, therefore, attractive devices for space engineering. The present paper describes theoretical evaluation method of the maximum heat transport capability of the capillary pumped thermal loops and simulation experiments to confirm the theoretical results and to observe stable operation of the loop by using of visible test loops. In addition, the means to increase the heat transport capacity of the loop has been discussed based on the estimation of the pressure loss in each process in the loop.
A theoretical and experimental investigation has been made of a flow past a two-dimensional inextensible membrane airfoil with slackness. The basic equations based on a linearized invincid theory have been analytically reformulated as a Fredholm integral equation of the second kind with an integral constraint, which has been solved by the degenerate kernel method. The experiment has been made of the measurements of lift, drag and moment acting on quasi-two-dimensional membranes and the visualization of the flow past them. From the comparison of the analysis and the experiments, following conclusions are obtained. 1) The linearized inviscid theory can predict fairly well the essential properties of flow around membranes with very small slackness. 2) As the excess length exceeds about five percent of the chord length, viscous effects prevail over the inviscid phenomena. 3) S-shaped membranes exist but exhibit a sustained oscillation.
A new implicit finite-difference scheme for unsteady Euler equations is proposed in this paper. The quantities of the order of square of time-step are employed as unknowns of the scheme, which produce “delta-square form” of the algorithm. Present scheme has second-order time accuracy without iteration. The iteration process in the algorithm, which the scheme has as an option, improves the numerical accuracy and robustness. Numerical experiments show that the present scheme is very good not only for an unsteady problem but also a steady problem.
The two-dimensional smoke wind tunnel which was constructed in the Dept. of Aeronautical Engineering, The National Defence Academy, Yokosuka, Japan on March 1987 is introduced in this note. The essential points and the new ideas of the design are described and some pictures showing the flow field are presented.