Early work on mini-RPVs in the former British Aircraft Corporation, Guided Weapons Division was described in a paper presented at the symposium on ‘RPVs — Roles and Technology’ held at the Royal Aeronautical Society, London in January 1976. Since then research and development work has expanded in several areas.

Significantly, the Stabileye research RPV which in prototype form had made some limited flights at that time has been developed into a payload carrying RPV system for research and development work within the UK UMA Systems Research programme.

The surprising sequence of recent world political events and changes of government attitude have focused attention on our current state of armaments, readiness, and future intention in the fields of national and NATO defence. This affords an ideal opportunity for a discussion on that vital part of our national capability, the conventional armament of our aircraft. While this is a field which may not always receive the attention applied to other, more technologically glamorous areas, it is one which is playing a progressively greater role in the current and future defence scenario. Developments along this route have changed particularly rapidly during the past few years, and seem set to do so for a decade to come.

The memory of the early Comet tragedies lives on as a reminder that aircraft structures must be damage tolerant. Aircraft structures may be cracked in manufacture or in service as a result of fatigue, corrosion, incorrect maintenance, the impact of ground handling equipment or accidents such as a turbine disc break-up. A damage tolerant structure should retain adequate residual strength until any cracks are detected and repaired.

A practical application of two-dimensional subsonic bluff body flow research can be seen in the design, construction and positioning of tall slender buildings. Similarly, from a three-dimensional viewpoint, drag reduction and vortex control is an important factor in the latest road vehicle designs. From just these two examples it can be seen that the problem of flow about a bluff body is one of major practical importance, while at the same time being of great theoretical interest. However, despite many years of extensive testing, there has been little progress made on the theoretical investigation of turbulent base flows since the foundations laid down by Kirchhoff and von Karman. The non-steady processes in the wake, in particular the complex dynamics of vortex formation, have proved to be problems of formidable size.

In this paper, the author seeks to present in easy-to-understand diagrams the effect of external loads on the pretensioned bolt in a bolted joint. In most cases, bolted joints are tightened up with little thought for the size of the external loads that may later be imposed upon them. Since external loads always change the preload in the bolt, it is important to know by how much the bolt load changes. Too much preload leaves too little margin for the external or working load; too little preload and the cyclic stresses cause the bolt to fatigue, assuming the bolted joint is subjected to frequent working loads. No two bolts are alike, even under the most rigorous quality control production methods, but with more sophisticated nut and bolt tightening equipment coming on to the market, better results can be achieved. The use of these diagrams will help engineers and designers understand what is happening in the bolted joint.