From WOLF SEUFERT
David Fisher from Cardiff is, I hope, the only one of your select readers
who doubts Bernoulli (Letters, 11 August). An aircraft with a conventional
wing profile sustains lift even when flying upside down, since the reference
is not the ground but the surrounding air mass and an aircraft with a symmetrical
wing profile sustains lift at an angle of incidence higher than that of
a conventional wing. I leave the further explanation of these banalities
to the efforts of the gliding instructors around Cardiff.
Wolf Seufert Universite de Sherbrooke Sherbrooke Quebec Canada
