Areo. Uncertainties.

Progress, Volume VI, Issue 11, 1 September 1911, Page 803

Areo. Uncertainties.

1 o witness, as I have done, aeroplanes circling over cities, to see them making the vol plane, coming to rest, and starting off in a space of fifty feet or so, leaves the impression that there is no specific art in flying, and that its dangers are few. Such is far from being the case. I have also seen Bleriot turn turtle and writhe amid the flames of his burning mono-

plane. 1 have seen Latham (only two days ago as I write) projected to earth, his controlling gear broken; I have seen that much-honoured, deceased pilot, Cecil Grace, flying steadily one moment at an altitude of 300 feet, and the next drop fifty feet in a “hole” in the air. And I read to-day that a similar occurrence was met with by M. Hamel on a recent flight across country. This latter type of accident is similar to that which ended Poor Chavez’s life at the very moment when he had completed his flight over the Alps. It also caused the death of the Hon. C. G. Rolls.

M. Alexandre See, who has studied aerial phenomena for many years, claims to have discovered the cause of these unexpected “holes” in the air, and also how to avoid suffering from them. A “hole” in the air is a simple description of a zone of comparative —comparative to the velocity of the air contiguous to it. Let us suppose an aeroplane coming down against a wind of 10 yards per second at a speed of, say, 20 yards per second. It enters an “air-hole.” The effect is that the front planes are relieved of the wind pressure and drop down and forward. Not so the tail plane. This is for the moment opposed to the 10 yards per second "wind, and, therefore, remains sustained long enough to alter the trajectory of the machine as a whole, with the result that it dives precipitately.

M. See advises aviators to go slow when approaching the earth and when in the vicinity of trees, for these calm-zones exist principally in such localities, and to be on the qui vive to start up the engine if, and when, the front of the machine shows a tendency to pitch downwards, so as to give it the added impetus needed to sustain it.