The Fourth Handley Page Memorial Lecture, “Were the Wrights Wrong?”, was given by Sir William Hildred, OBE, CB, MA, Honorary Companion of the Society, Director Emeritus of the International Air Transport Association, in the Society's Lecture Theatre on 19th May 1966. Opening the meeting the President, Mr. A. D. Baxter, MEng, CEng, FRAeS, reminded the audience that the Handley Page Memorial Lecture was arranged jointly by the Cranfield Society and the Royal Aeronautical Society. Both Societies had much reason to honour the name of Sir Frederick Handley Page and the arrangements by which they alternated in providing both venue and the lecturer had proved a happy one.

On this occasion the Royal Aeronautical Society was glad to welcome its friends from the Cranfield Society and other guests and visitors, particularly Lady Hildred. “HP’s” early reputation was built on the practical application of aerodynamic flow, but it had extended far and wide and to many fields beyond aerodynamics and even beyond aeronautics. He thought it was in this spirit of his wider service to mankind that they paid tribute that night. Certainly he felt that was the approach their lecturer had taken.

Sir William Hildred was well known to most people through his long and valued service to the International Air Transport Association. On completion of his studies at the University of Sheffield in 1914, he joined the Army and served for the duration of the 1914-18 War. In 1919 he had started his Civil Service career in the Treasury, becoming a Finance Officer, then Head of a Branch of the Ministry of Agriculture and Fisheries and later a Deputy General Manager of the Exports Guarantee Department. In 1938 he had begun his long association with civil aviation as Deputy Director General of Civil Aviation at the Air Ministry, becoming Director General in 1941. In 1946 he had joined IATA as Director General, where he had done such magnificent work ever since until his retirement only a month ago. He had received many honours, including Grand Officer of the Order of Nassau, Commander of the Order of the Crown of Belgium and, not least they hoped, Honorary Companionship of the Royal Aeronautical Society.

The title of this paper was chosen some time ago. In view of events experienced over the past three years on some modern civil jet transports, I propose to devote the time available to the subject of stall characteristics, together with some of the associated problems and with the methods of solution.

Before anyone else raises the point, I wish to point out that the term “Super Stall” is nothing more than popular jargon and is equally as objectionable to the purists as “Deep Stall” or “Stable Stall”. It will, I hope, become clearer later as to what particular characteristics these terms apply.

After some introductory remarks about Reynolds and Prandtl the results of some work in the field of the aerodynamics of propulsion plants will be described. In this context there are, first, cascade flows in which the influence of such parameters as Reynolds number, Mach number, axial pressure ratio, turbulence and boundary constraint have been studied. Investigations in the transonic and supersonic ranges will also be considered.

Flows with heat addition at both subsonic and supersonic speeds are then dealt with, including reaction-kinetic effects in the ignition of fuel and in the recombination processes in expanding jets.

The flow problems which arose in the development of the rocket test beds for the third stage of the ELDO rocket will be described and, in particular, the special rocket steam generators and flow problems associated with the strong cooling of the hot rocket gases will be discussed.

Next we shall deal with work on the flow processes in the acceleration of electrically-conducting gases. Some results are described of the self-magnetic—the Hall current—and the electrodeless electromagnetic acceleration.

Finally some problems of measurement techniques will be touched on.

The production of required velocity profiles in a duct or wind tunnel is a necessary part of much research aimed at understanding fluid behaviour. Perhaps the most obvious application is the simulation of wind gradients for the study of wind effects on structures, but equally important is the study of diffuser and duct behaviour when subjected to a variety of known and convenient velocity profiles. Furthermore, the effects of the variation in turbulence characteristics within a range of identical velocity profiles produced by different methods are not clearly understood.

In recent years the use of turbine flowmeters in industry has become well established. An NEL publication by Myles and Harrison gives an excellent survey of their construction, use and calibration. It seems from ref. 1 that calibration by the manufacturers is done mainly with liquids, presumably in order to use a weighing technique to obtain the volume flow. A typical calibration report for a gas is that of Redding where the flowmeter in question was calibrated on air against a vena contracta tapped orifice. Eight experimental points are given on this calibration curve over the range of the meter. It was considered of interest to calibrate a turbine flowmeter on air against a pitot tube traverse. This method is generally regarded as being of greater accuracy than an orifice or nozzle method. Also it was considered that if a large number of readings were taken the amount of random scatter, if any, would become apparent.

For the past few years there has been some interest in aerofoils with blunt trailing edges but most work has been associated with the investigation of the base pressure and the pressure distribution on the aerofoil has received little attention. Nash proposed a method of calculating the pressure distribution on aerofoils with blunt trailing edges in the absence of a vortex street, that is with the vortex street suppressed by means of a splitter plate or base bleed. He assumed that the wake of the aerofoil could be taken into account in the calculation by specifying a pressure distribution along the wake and then applying thin aerofoil theory to the aerofoil and wake. This leads to a mixed boundary problem with the aerofoil shape and the wake pressure distribution specified and the calculation is laborious.

Various natural phenomena can result in sufficient difference of potential between an aircraft in flight and its very rapidly changing surroundings that, immediately adjacent to the aircraft extremities, there will exist potential gradients high enough to produce local atmospheric ionisation or “corona”.

Since there is no effective method known to prevent the development of these potential differences, aircraft are commonly fitted with a number of so-called “static dischargers” or “neutralisers” to control the nature and occurrence positions of the corona in such a way as to minimise the generation and radiation of RF noise, which would otherwise be quite capable of causing complete mis-function of navigational aid systems.

The utilisation of high speed digital computers for structural analysis is commonplace in the aircraft industry. However, despite this, no information appears to exist which indicates, nationally or internationally, the degree of utilisation in the various companies.

In an effort to give some indication a world survey was undertaken.