Ladies and Gentlemen,

I am sure you will agree that it is quite unnecessary for me to introduce DR BENNETT formally He has previously lectured before the Helicopter Association, to say nothing of numerous lectures to learned Societies both at home and abroad I also feel quite certain that most of you are familiar with his background in the rotary wing field of aviation

On behalf of all Association Members and their guests, I should like to thank the Directors of the Fairey Aviation Company for their kindness and hospitality to us today, and also thank those members of the Fairey Company Helicopter Division whose work has made this visit possible

Finally, on behalf of the Association, may I congratulate the Fairey Aviation Company again, together with all those responsible, for the excellent show in their recent successful attempt to raise the Helicopter world speed record Personally, I feel that given the right conditions they are quite capable of increasing this record still further

The importance of reliable airworthiness criteria is stressed in an introductory paragraph Practice in aeroplane design is reviewed briefly, noting particularly the current tendency to permit increasingly severe fatigue loads The principal loads on the elements of a helicopter are enumerated, and consideration of their repetitive nature leads to an extended discussion of fatigue failure and methods of correlating fatigue loads Suggestions are offered for a rationale of provisional strength requirements and the amendments desirable following the establishment of additional data The need in this connection for extensive V-g and blade stress records taken in operation is emphasised

Many people in Great Britain are now confident that helicopters will shortly be in general use for a variety of commercial purposes Some of these anticipated functions are not new to air transport undertakings—certain feeder-line services within the British Isles, for example, may well be operated by helicopters—but the fundamental ability of the helicopter to take-off and land in confined spaces gives it an additional scope in circumstances which preclude the use of fixed-wing aircraft

LADIES AND GENTLEMEN,—As you know, this is the first lecture of our 1948 49 Session—a series which I am sure you will find both interesting and instructive It is also the first time we have been privileged to use this room for our Meetings and our thanks are due to the President and Council of the Royal Aeronautical Society for granting us this facility

Our lecturer today has chosen a subject which is becoming of very great importance now that Helicopters are being used in a definite operational sense Mr USHER IS peculiarly well suited to talk to us on “Navigational Aids to the Helicopter” as he is qualified as a R A F Advanced Specialist Navigator, and has some experience of Helicopter Pilotage He is a Fellow of the Royal Meteorological Society and an Associate of the R Ae Society and, needless to say, a Member of our Association and also holds the Bachelor of Science Degree and Diploma of Education—both of London