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Aviation History
1964
1964 - 2053.PDF
4.000 74 FLIGHT International, 9 July 1964 Spaceflight and missiles temperature would be high—say, 2,000°C. The thicker the coating, the greater the economy in coolant flow. The diagram (page 73) shows the type of composite structure which may result. At Bristol Siddeley, facilities have been set up to enable materials and composite structures to be assessed under simulated environ- mental conditions. These facilities are yielding solutions to the structural design problems which arise in attempting to engineer a Mach 7 ramjet. It appears that a workable structure is feasible with present-day technology, although it will be some time before a long-life structure of light weight is developed. As with structures, the main problem in cycle performance arises from the very high gas temperatures—temperatures at which air behaves very differently from that of an ideal gas when its state is changed. Although real-gas effects are present in the flow through the intake of a hypersonic ramjet, these effects are most apparent in the combustor and exhaust nozzle. Assuming a subsonic com- bustion cycle would be chosen for a ramjet to accelerate from Mach 2 to Mach 7, dissociation in the post-combustion products and failure to recombine completely during expansion in the exhaust nozzle is the major problem influencing cycle efficiency. In providing experimental data to complement the theoretical work on the recombination problem, Bristol Siddeley facilities include a nozzle thrust rig and a large shock tunnel. This problem must be solved if hypersonic ramjets utilizing subsonic combustion are to become attractive powerplants for efficient long-range flight. Blue Streak Testing The Development and Testing of Blue Streak by C. R. Hume of Hawker Siddeley Dynamics, Salis- bury, South Australia (read by G. K. C. Pardoe). The paper outlines the testing principles used for Blue Streak. Environmental and systems testing, development, static firings and launching are discussed, together with results obtained. A number of proposals and suggestions for the control and organization of similar activities involving multi-stage vehicles are presented. Air-breathing Engines Air-breathing Engines for Recov- erable Boosters by F. Filippi of Politecnico di Torino. The potenti- alities and limitations of the use of air-breathing engines in winged recoverable boosters are briefly discussed. It is suggested that a major change in research policy is necessary to allow the study and development of such engines and vehicles. Following a brief introduction to the current and proposed cycles suitable for use in air-breathing boosters, the reheat turbojet, turbo- ramjet and ramjet are discussed in more detail. In order to assess the real performance of air-breathing engines, one must consider fully the "off-design" case. The parametric study of optimum engines, each designed for a given flight condition, may lead to big over- estimates of their performance. The main problem is the matching of inlet and engine perfor- mance: it appears possible to extend the usefulness of "advanced state of the art" turbojets and turbo-ramjets up to Mach numbers usually regarded as suitable only for ramjet engines. It is suggested that the practical potentialities of hypersonic ramjets, even with supersonic combustion, appear rather scant for the Mach number range 8-14. The paper suggests that more research is needed on such engines as the internal combustion wave engine, which could possibly solve some of the operational problems of air-breathing boosters. Recoverable Systems Studies on a European Recover- able Space Launcher System by Jiirgen Lambrecht of Junkers Flugzeug und Motorenwerke, Munich. An analysis of the require- ments of European launcher systems indicates the need for recovery of all stages. This leads to the reusability of all or part of the system, which results in a marked increase in reliability and, at the same time, in a decrease of transportation cost. The missions of the reusable aerospace transporter are discussed and the resulting requirements are indicated. A number of proposed reusable launch systems are analysed for comparison. It is suggested that certain trends exist which can be extrapolated to European requirements. In this way a number of important results are found which give an indication of the most likely system to meet the European requirements. 4 S 6 7 FLIGHT MACH NUMBER-M. Equilibrium temperatures for various surfaces of a hypersonic ramjet with no regenerative cooling (Hawkins) Two-stage space transporter proposed by Lambrecht would have a launch weight of 100 metric tons and would carry a three-ton payload An example of a possible solution is the two-stage space trans- porter shown on this page, in which both stages employ hydrogen, oxygen rocket engines, three in the first stage and one in the second stage. Horizontal take-off is envisaged, with catapult assistance by means of a hot-water rocket which would accelerate the vehicle to 250m/sec. The craft would have a launch weight of 100 metric tons, reducing by 79 tons at stage separation, and would be designed to transport a payload of three tons into a 300km orbit. Approximate costs are suggested. In the author's opinion this would represent a project for a reusable space transport system which would meet European requirements and which lies within European financial and personnel capabilities. The vehicle could be built by a group of European countries either by themselves or in co-operation with the USA. Eurospace Activity Work of Eurospace concerning the Aerospace Transport by Prof Maurice Roy of Academie des Sciences, Paris. A committee of Eurospace has been studying the overall question of the aerospace transporter for over one year, and a report on the subject is to be published in the near future. The utility of such a vehicle is recognized and its development on a European basis is believed to be possible. Such a project could be implemented in 15-20 years, and would involve a multi-stage system, since no single-stage solution could be conceived. A European programme along these lines is from all points of view feasible. Other Papers Among the other papers presented at the symposium were Liquid-oxygen/Liquid-hydrogen Rockets for Space Transporters by M. Bedel (SEPR); High-temperature Problems at High Mach Numbers by Prof L. Broglio (Rome University School of Aerospace Engineering); Aeroelastic Problems of Recoverable Boosters for Space Vehicles by Prof P. Santini (Rome University School of Aerospace Engineering); Nuclear Reactors as Energy Sources for Space Propulsion by H. Unger and R. Pruschek (Institut fur Hochtemperaturforschung, TH Stuttgart); and On the Optimum Guidance Law for both Thrust-coast-thrust and Continuous-thrust Transfer to Orbit of a Space Vehicle by R. Cosaert (ELDO) and R. Roelandt (Bell Telephone, Antwerp).
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