In some ways I am an intruder into this discussion on the Design and Construction of Rotor Blades, because my paper deals with what happens to rotors long after they have been designed and constructed, when, that is to say, they are passing through the hands of the test pilot, the operating pilot and the maintenance engineer I shall try to confine myself to those parts of the rotor’s career which have repercussions on design and construction

Tuning, whether of an engine or a musical instrument, consists of adjusting all the variables available in a systematic manner calculated to make the device as a whole work in the best way possible If the device is a piano, this may mean doing what the piano tuner does on his three-monthly visit, but it may perhaps involve a bit of what happened when the earlier types of piano were developed into what J S BACH called his “well-tempered clavier”