When we talk about the system of air transport regulation we normally refer to the processes by which governments exercise authority over the licensing of airlines to routes and control the fares and rates which are charged on those routes. Sometimes the concept of air transport regulation is extended to embrace the controls which governments exercise over the technical standards of airline operations, and thus include the licensing of personnel and the certification of airworthiness standards. In this lecture I propose to use the term “air transport regulatory system” in a much broader sense. I want the term to be interpreted as meaning the total system by which all relevant aspects of public policy are brought to bear upon airline operations and the ways in which they influence the air services which are available to the travelling public. Under this definition of air transport regulation I shall, for example, include governmental interests in promoting a high rate of technological progress in aeronautics as part of the overall system.

I was glad to be asked to talk to the Graduates’ and Students’ Section of the Society because, in the years to come, it is you who will be carrying some of the responsibility for developing the air transport industry of this country to extents which will make today's efforts appear puny. In an industry which is doubling in size every five years—a fourfold increase during the next decade—it is important that we get the structure right. There is a chance to do this now, while the whole future of British commercial aviation is under review that may not, indeed should not, occur again for many years. Change inevitably brings disruption and upheaval but some re-organisation and re-orientation is essential if the industry is to have an expansive but reasonably stable future bringing greater efficiency, higher profitability and enhanced benefits to the national economy. The recent White Paper Civil Aviation Policy holds out little prospect that, under a Socialist Government, these aims will be fully realised in the Seventies.

The object of this talk is to give you a situation report on the Concorde flight test programme and to indicate the progress made to date.

Two aircraft have been engaged on the programme so far, the prototypes 001 and 002 (Fig. 1). The French base for Concorde flight test operations is at Toulouse and the British flight test base is at Fairford in Gloucestershire. The two prototypes will be joined in the flight test programme next year by the two pre-production aircraft, 01 and 02.

As is well-known, Concorde is a slender delta wing aircraft and it may be appropriate at this stage to state some of the considerations that led to the choice of this configuration. By virtue of a large root chord, the delta wing can overcome all the disadvantages of lack of structural stiffness and lack of wing volume associated with thin highly swept wings and yet remain aerodynamically thin.

In the fourteenth Henson and Stringfellow lecture delivered to the Society earlier this year, Speechley compared the development of the helicopter with that of conventional fixed-wing aircraft. He pointed out that some ten years elapsed between Kittyhawk and the mass production of military aircraft which occurred during the First World War, and that there were a further two decades before the commercial breakthrough of the DC2/3 aircraft. Initial helicopter progress followed a similar pattern but the commercial breakthrough is still awaited more than twenty years after the beginning of large-scale military procurement.

The fundamental mechanics of the helicopter involving a number of rotating components make the machine subject to vibration. The prime source of excitation is the main rotor and at the design stage of a new helicopter detailed consideration should be given to the level of forcing produced at the hub. Up to the present time, designers using sophisticated mathematical models have not been completely successful in predicting, for a complicated airframe, the vibratory response to this forcing.

The purpose of my contribution is to explain the need for dynamic testing in terms of defining the design problems where testing is required to assist or substantiate decisions made in the light of mainly theoretical evidence in the initial stages of design before hardware becomes available for testing.

I have interpreted the title in the broadest sense of the word vibration so as not to restrict the presentation only to testing associated with assessing or minimising the vibration of helicopters, but to include problem areas which result in dynamic testing requirements.

The advent of air- and spaceflight vehicles and that of nuclear explosions as well as the trend of constantly increasing and higher structures have brought attention to the need for better understanding of the dynamic response of such a system. The knowledge of free and forced large amplitude vibrations of structures or parts of it, as well as the response of them to pulse excitations, are of pronounced influence upon their design. Whether one deals with aerospace structures or civil structures, such as bridges or buildings, one is faced with the prediction of loads due to some wind or gusts.

Many authors have established that a finite wing in inviscid flow has a theoretical maximum lift coefficient. One formula based on a theoretical model of a rolled-up vortex system aft of an elliptically loaded wing is

where AR is the aspect ratio. Ref. 6 criticises the validity of eqn. (1) but at least eqn. (1) gives the order of magnitude of an inviscid CLmax.

In spite of the large number of published works on panel flutter there appears to be a wide gap in the literature concerning the flutter of skew panels. For instance, recently the flutter behaviour of skew panels in supersonic flow has been presented for a simply-supported boundary condition using double Fourier sine series to represent the deflection surface. Apart from this publication there is practically no literature concerning flutter of skew panels except refs. 3-4 which consider the flutter of skew panels clamped on all the edges. The method used in ref. 3 is the common 4-mode analysis by using the Iguchi functions for representing the deflections and in ref. 4 the same problem is solved by the use of beam characteristic functions. One inherent difficulty in these conventional methods, was that no single function could be chosen to represent the deformation which satisfied various boundary conditions, with the result that the entire analysis may have to be repeated with different assumed functions for accommodating different boundary conditions. Hence, a general method was proposed in ref. 5 for the study of panel flutter problems of arbitrary geometry by the Matrix Displacement Method, which permits application to problems with practically any geometrical boundary conditions on any or all the sides.

In most dynamic analyses, it is customary to use a coarser mass idealisation than structural idealisation especially if stresses are to be involved. Compatibility between the stiffness matrix and the smaller mass matrix M is achieved by reduction of the stiffness matrix. Guyan has shown that the reduction is equivalent to a transformation of the original matrix K :

where KR is the reduced stiffness matrix and T is the transformation matrix which contains stiffness terms.

A survey of the Messerschmitt-Bolkow-Blohm company's activities in the helicopter field amounts to a review of the past 15 years. The scope of these activities, as measured by their technical diversity, can only be appreciated in full if something is known of the progressive thinking involved, the company's courage in taking commercial risks and the development and contract situation in post-war Germany.

The Bolkow company evolved from a small engineering office into an aeronautical company in 1955, and from this time on the development of rotary wing systems was one of its important development aims.