F-111 aircraft are in service with both the Tactical Air Command and the Strategic Air Command in the USAF. The aircraft performs primarily in the fighter-bomber role for TAC and as a strategic bomber capable of high and low altitude penetration with SAC. Over 100 000 flight hours have been accumulated by the F-111 fleet including a limited amount of combat flying. The broad spectrum of service requirements for the F-111 include short field take-off and landing capability, all weather and deep interdiction, close air support with large payloads, high altitude high speed air defence, and world-wide deployment with minimum tanker support. Major technical advancements were necessary in meeting these requirements, including most notably a variable-sweep wing. The unswept high aspect ratio positions provide for maximum range and endurance and short take-off and landing distances. The wing in moderate sweep positions provides an efficient configuration for sustained high subsonic and high altitude supersonic flight. Supersonic flight at sea level at speeds in excess of the capability of any other aircraft plus supersonic speeds at altitude in excess of Mach 2.0 are achieved in a most highly swept low aspect ratio wing position.

Aeroplanes are often noisy, and sometimes smelly. Some of them also produce smoke. The purpose of this paper is to attempt an assessment of these and other forms of environmental pollution, also to consider the engineering and administrative measures which are being taken to control them. But before embarking on the subject one must try to put the matter in perspective. As I see it, the threat to the environment does not just come from aeroplanes, transport systems, factories or advancing technology. It comes from man.

Involvement with the development of an aircraft engine can create deep mental scars. There seems to be an almost infinite variety of ways to encourage failure when considered in detail, and at the same time, there is no rule that will ensure success, except “Don't make any mistakes!”, a rather absurd bit of guidance. There is a small number of basic resources necessary for success, but only proper application of these resources can permit success. The basic resources are money, manpower, facilities, and knowledge. This paper provides, on the basis of one man's scar tissue, some guidance in creating an environment to encourage success. This introduction defines the general size and importance of the problem and the resources applied to the paper. The problems of organisation are outlined, followed by a definition of the game rules. The problems line people must overcome are discussed, followed by what to expect and where to inspect for problems. The paper ends with a suggested approach to the technical portion of the problem.

A finite element which allowed warping constraint effects in open tubes to be taken into account was developed in Ref. 3. Because of the assumption of linear variation of the warping constraint direct stresses along the length of the element its flexibility matrix was very simple, but approximate.

In this note the flexibility matrix for an “exact” element is derived which will give results which coincide exactly with those obtained from the theory given in Ref. 1. It is assumed that the applied torque and cross-sectional properties do not vary along the length of a given element, but variation from element to element is, of course, possible.

Modern balances are rugged, sensitive and easy to read. A top-loading balance with a capacity of 1 kg and digital readout to 0.01 gm has been adapted for use as a micromanometer. A sketch of the arrangement is shown in Fig. 1. It will be seen that there is no modification to the balance itself, which can still be used for its normal laboratory function, and no calibration is required for pressure measurement provided the diameter of the fixed drum is known.

In a recent paper Garner discusses, among other topics, the induced (inviscid) drag or lift dependent drag, on finite wings which have effective antisymmetric incidence distributions. One example concerns a finite wing whose incidence varies linearly in the spanwise direction as

This wing experiences an overall induced drag which is made up from two contributions.

The rising demand for short-haul air transport with its attendant problems of community disturbance, airport congestion and increasingly longer total journey times is well recognised in many parts of the world. Equally accepted is the need for a radically new solution to these problems with a major V/STOL transport sub-system which can both be integrated with operations at existing airports and extended as necessary to new airports in urban areas without sterilising large areas of real-estate. All this has been argued at great length many times in many places and there have been many “solutions in search of the problem”. This paper reviews some of the possibilities from the engine manufacturers’ point of view without commenting on the relative merits of rival aircraft proposals.