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Aviation History
1957
1957 - 1319.PDF
FLIGHT, 6 September 1957 407 ANGLO-AMERICAN AERONAUTICS The Sixth Joint R.Ae.S.-LA.S. Conference at Folkestone A PPROXIMATELY 650 delegates are expected to attend /% the joint aeronautical conference organized by the Royal •*- -*• Aeronautical Society and the Institute of the Aeronautical Sciences in Folkestone next week. These will include 120 from the U.S.A., and representatives from Australia, Belgium, Canada, Czechoslovakia, France, Holland, India, Italy, Poland, Russia, Spain and Switzerland. The conference will be officially opened by the Mayor of Folkestone, the President of the R.Ae.S. and the President of the I.A.S. at the Hotel Metropole at 9 a.m. on Monday, Septem- ber 9. A total of 16 technical papers will be presented, and the conference will end on Thursday, September 12. The technical feasibility of VTOL and STOL aircraft is a topical subject to be discussed, with M. O. McKinney's paper as a basis. Chairman of the session at which this paper will be presented is D. Keith-Lucas, chief designer of Short Bros, and Harland, a company directly involved in a VTOL project. Associated with the problem of vertical take-off and landing are boundary-layer control and the control of propulsion systems. Lectures by C. W. Harper, F. K. Moore, J. C. Sanders and G. M. Sturrock deal with these problems. The design and operation of advanced supersonic aircraft involve considerations of kinetic-heating effects, choice of airframe materials, integra- tion of engines and airframe, instrumentation and overall aircraft safety, and these aspects are covered in contributions by J. Taylor, L. Schapiro and E. H. LaBombard, W. J. Strang, R. L. Bisplinghoff and E. A. Winner, A. Stratton and A. E. Russell. The lecture by Schapiro and LaBombard gives factual experience of the use of titanium in aircraft, while Russell's paper may well lead to further controversial discussion on the con- flicting design concepts of "fail-safe" and "safe life." Turbine engines and repairability is discussed by A. Harvey- Bailey, and consideration to future nuclear power units is given in the paper by J. V. Dunworth. Stability, one of the oldest problems in aircraft design, remains important to the present day, and the lecture by M. Goland on the consequences of aeroelastic effects should arouse much interest. At the other extreme, hyperballistics is one of the most recent topics to come within the orbit of aeronautical engineer- ing, and H. H. Kurzweg's paper will be of particular interest to missiles specialists. The conference closes with the paper by T. C. D. Whiteside, which considers the future effects on aircrew of the new developments in aviation. Summaries of the 16 papers follow. We hope to report the major papers at greater length, together with conference discus- sions on them, in the near future. THE PAPERS N.A.C.A. Research on VTOL and STOL Aeroplanes By M. O. McKINNEY, B.S., assistant head of the free-flight tunnel, Langley Aeronautical Laboratory (National Advisory Committee for Aeronautics), Langley Field, Virginia. This paper presents a summary of N.A.C.A. research on aero- planes capable of vertical take-off and landing and short take-off and landing. This research has covered propeller- and jet-powered VTOL configurations of both the fuselage-vertical and fuselage- horizontal types, and has also covered both propeller- and jet- powered STOL configurations. Two general fields have been covered in this work—stability and control, and general aero- dynamics (or performance) in hovering and at low speeds. The emphasis in this paper is on the problems that have been encoun- tered and the solutions, if any, that have been worked out. When- ever the results of the research on which this paper is based have been published, these papers are referenced. Nuclear Mobile Propulsion with Particular Reference to Aircraft By J. V. DUNWORTH, C.B.E., M.A., Ph.D.. head of the reactor division of the UJC, Atomic Energy Authority research group, Harwell. Nuclear reactors are discussed from the general point of view and from the aircraft angle. Reliability is a first consideration; for instance, while a power station has the national grid system to fall back on, this would not be the case with an aircraft powered by reactors. It is seen that since the size of an aircraft reactor must neces- sarily be the minimum possible, the fuel will probably have to be highly enriched uranium which is very expensive. Weight in an aircraft is of primary importance so that the neces- sary shielding for a reactor becomes a major problem. Various solutions are considered and it is pointed out that the choice of coolant has a strong influence on overall shield design. Safety precautions are considered briefly. All these aspects are finally considered as they would occur in an aircraft project. Some of the research needed if nuclear power is to be adapted to aircraft use is indicated briefly and it is shown that both the time spent and the cost involved are likely to be deciding factors. An estimate of 15 years to reach the prototype stage is made. Control of Supersonic Propulsion Systems By J. C. SANDERS, B.S., MS., chief of the dynamics and controls branch, Lewis Flight Propulsion Laboratory (National Advisory Committee for Aeronautics), Cleveland, Ohio. The control problems arising from the presence of the air-intake diffuser in a supersonic propulsion system are considered. The air-consumption characteristics of the turbojet and the air-delivery characteristics of the diffuser are compared. Some diffuser geometry properties that influence the mismatch between engine and diffuser are inspected, and geometric variables that may be manipulated by a control are pointed out. The uniqueness and advantages of sensing the position of the normal shock in the diffuser and using this shock-position signal for control of the ramjet and the diffuser with turbojet are empha- sized, and problems in sensing shock position are discussed. The effects of control seryomotor response rates on the ability of the control to restore the diffuser to proper operation following a disturbance are investigated, both for small disturbances where linear conditions prevail and for large disturbances where dominant non-linearities exist. The Electrical Control of Power Plants By G. M. STURROCK, B.Sc, technical manager of Ultra Electric, Ltd., London. As an example of the approach to the problems of the electrical control of aircraft power plants, the "Electric throttles" of the Britannia have been particularly selected for discussion in this paper. This control system has been chosen because it represents a relatively complex equipment, embodying most of the control problems of the recent generation of gas-turbine engines, together with the problems of throttle actuation in large aircraft. It is also of topical interest with the recent advent of the Britannia aircraft into regular commercial flying. Consideration is given to the limitations which beset the designer of electrical engine-control equipment. Reliability, bulk and weight, ruggedness, and per- formance requirements are set forth as the prime considerations. The early history of the Britannia control system is outlined to illustrate the approach pursued. The mode of operation of the system is discussed and explained, together with the philosophy of safety which was evolved and followed. A brief description is given of the magnetic amplifier, around which the control system is based. Finally, some record is given of the flight experience, both with this control system and with other systems making use of the techniques briefly outlined in the paper. Alleviation of Kinetic Heating Stresses By JAMES TAYLOR, M.A., F.R.AeS., superintendent, kinetic heating division, Structures Department, Royal Aircraft Establishment, Farnborough. An investigation is made of ways in which thermal stresses and material temperatures can be reduced in aircraft structures. Men- tion is made of the available means of modifying the form of the structure but the investigation is mainly directed to the value of insulation and cooling. It is shown that, for any particular con- figuration of multi-web construction, insulation can be added to bring the sum of the heat flow resistance of the air and the insula- tion to a certain value without appreciable reduction in stress. Further increases reduce thermal stress but in all cases the equilibrium temperature is unaffected unless cooling is present. Cooling, on the other hand, always has a beneficial effect on both equilibrium temperature and on thermal stress. Once cooling has been introduced the addition of insulation will reduce the equilibrium temperature still further. A simplified empirical procedure for quick analysis is introduced which has a general application in any preliminary design studies. An important feature in the design of an aircraft incorporating cooling and insulation is that certain new requirements of flight plans are introduced. A change of height at constant Mach number will introduce thermal stresses. Increase in height produces cool- ing rates that are comparable to those caused by practical aircraft decelerations. Reduction in height produces heating rates that may be large compared with those produced by practical accelerations. [Continued overleaf
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