The CHAIRMAN, in introducing the Author, expressed great pleasure in welcoming Mr MacMahon to this, the first lecture of the eleventh series of Annual Lectures on the helicopter situation He said that Mr MacMahon was educated at Twickenham Technical Institute During the war, he was with the Admiralty Research Laboratory, working on electromc equipment for anti-submarine warfare development After that, he was engaged on electronic developments with one or two firms and subsequently with the De Havilland Propellor Company as a development engineer engaged mainly on research and development of flight test equipment for high speed aircraft