Jasper County Democrat, Volume 22, Number 99, Rensselaer, Jasper County, 10 March 1920 — Air Waves. [ARTICLE]

Air Waves.

That aircraft actually navigate a kind of invisible sea is revealed by a series of motion pictures, the first of their kind ever taken, that show the air in motion against the wings of an airplane. Three miles of film were used in making the photographs, and they reveal the plane, instead of being continuously upheld by the air, traveling from crest to crest of a series of waves; in more technical words, the element of rarefaction which produces the lifting power of an airplane is not constant, but is exerted in intermittent moving air waves, not unlike the waves of the ocean. These air waves have their period of formation, followed by a collapse which, again like the sea, has its undertow; and, during more than a quarter of the time in flight, the air flow created by the air screws has no lifting power on the wings. To take the pictures required a special camera devised by the invention section of the United States army.