Introducing the Author, the Chairman said We have a very important lecture tonight before our annual dinner, this being one of the principle evenings of the year Commandant BORIS has been good enough to come to give us a Paper which I think will stimulate a good deal of discussion We can listen to him with much respect, for he is a man with enormous flying experience—some 6,000 hours total, with 400 hours in helicopters He is managing director of Hehcop-Air, which is Hiller’s representative in Europe He had a considerable number of racing successes in light aeroplanes in his early flying days, and during the last war he had a very distinguished aviation career, which is shown by the fact that he has the honour of being a Member of the Most Excellent Order of the British Empire a well as being an Officer of the Legion d’Honneur with the Croix de Guerre, the Resistance Medal and many other distinctions

Self excited vibrations of helicopters on the ground have been the cause of several accidents It is, therefore, essential that the means of ensuring freedom from such phenomena should receive serious attention

The theory of R P COLEMAN, is briefly reviewed and compared with results obtained from model rotor tests This comparison affords general confirmation of the theoretical results

The theory of a rotor on idealised supports is applied to a single rotor helicopter of known hub impedance Then experimental methods for determining this impedance are described

Finally, the influence of Ground Resonance on undercarriage design is reviewed The influence of shock absorber struts and tyres on the coupled rigid body modes of the helicopter is discussed and three undercarriage schemes representing alternative approaches to ground resonance elimination are examined It is found that, with respect to ground resonance, the most advantageous system for land based operations is one in which all the helicopter-undercarriage modes have very low frequencies

An Appendix indicates the application of the theory to a twin rotor helicopter of any configuration

I must depart at once from my script to thank Wing Commander BRIE for his kind introduction, and add that with such a formidable array before me my immediate reaction is to take refuge in a corner and re-write much of my little paper packing it with graphs, square roots and at least a mention of omega However, time does not permit this

As you know, this is a short paper outlining some experiences that have come my way while testing helicopters I hope I have been able to strike the right note, and that in my avoidance of “digging up” technical data and figures, the general facts are not too woolly

This paper deals solely with the operation of helicopters from ships in the Royal Navy

Since the great majority of helicopter flying at sea has been carried out from aircraft carriers, I propose first to deal with these operations, and secondly I shall describe a series of trials carried out in 1950 to determine the feasibility of operating from a specially constructed platform on a merchant type vessel

As an introduction I should like to give a brief history of the helicopter in the Royal Navy

In 1943 a small number of pilots were sent to the United States to learn the principles of Rotary Wing flying and on their return to this country a flight was formed equipped with Sikorsky R 4 machines Its task was to carry out communication, photographic and radar calibration duties

Increased helicopter operational requirements and the consequent advances in operating techniques are producing problems which need early recognition It is true that an increased requirement usually means an improvement in performance, but invariably each advance in performance introduces new handling problems In this short paper I will discuss two such handling problems as they effect the present military use of helicopters

Already the extension of pure helicopter flight for world-wide operation in any reasonable weathers and up to higher ceilings has provided new handling problems which we encounter regularly in our present work These I will discuss under the general headings of high altitude and instrument flight I am considering the problem of high altitude handling as a manufacturers problem, and instrument flight as a users problem

Mr Chairman, Ladies and Gentlemen I have been in some dilemma about the type of paper to read before such a technical body I would like very much to include a brief history of whaling, the zoology of whales, and the economics of whaling I would like to describe rounding Cape Horn in a full gale, and to tell you in an informal way of experiences during a hurricane in latitude 68 South last season, of terrible accidents and suicides, of personal sacrifice, of brilliant seamanship, of bitter disappointment, and of super-human efforts I would also like to recall some amusing, some sad and some frightening personal experiences that I had during two whaling seasons

Instead, I shall describe the structure of a whaling expedition and summarise last season’s work, trying to make a comparison between present whaling methods and new techniques offered to the whaling industry by the use of helicopters I shall conclude with a summary of the advantages to be gained by the use of helicopters for whaling

I wish to signify my appreciation of the honour of being asked to address the Members of The Helicopter Association of Great Britain and their guests I would also like to thank the Chairman for his introduction, and to pay tribute to the notable work being done by the first two speakers Both are test pilots of exceptional skill and experience, and congratulations are due to them on the papers they have delivered this evening My paper deals with the development flying on a new British type of helicopter from a civil operator's point of view and, quite frankly, I find it a most difficult task, not because the subject matter is difficult, but because to date we have only flown 120 hours on this new type in 15 months The slow rate of progress was due mainly to the many teething troubles associated with prototype aircraft

In the first part of the paper a brief review is made of major items for research in the helicopter field, the subjects touched on including rotor aerodynamics, stability and control, evaluation of configurations, vibrations and fatigue, and operational aspects An outline is given, in the section on stability and control, of work being done at A & A E E in connection with the assessment of the longitudinal handling characteristics of helicopters The second part of the paper contains an account of recent work at A & A E E on the low speed and take-off performance of a helicopter An empirical method of low speed performance estimation is described, and the variation with wind speed of the ground effect on a rotor is discussed theoretically and on the basis of experimental results A theoretical analysis of the forward take-off motion of a helicopter is briefly presented, and the final section is concerned with the performance of a multi-engine helicopter in the event of failure of one engine, with particular reference to the possibility of safe operation from the type of site proposed for civil use

The paper describes some of the overseas operations which have been conducted by AIRWORK LIMITED in the last eight years and in places ranging from South America via the Middle East to New Zealand It examines some of the problems that have to be faced by an overseas operator, and suggests the possibility of using helicopters for certain of the work which is now earned out by fixed wing aircraft It concludes that providing certain conditions as to performance and operating cost can be met there is a definite place for the helicopter in such overseas operations