Abstract
IN his presidential address delivered before the Royal Aeronautical Society on April 26, Mr. H. E. Wimperis discussed the “Natural Limits of Human Flight”. He showed how relatively thin is the atmospheric shell in which we live. Birds, he considers, have reached the limits of perfection in natural flight, comparatively little progress having been made in the last thirty million years, whilst the “present attainments in human flight have all grown from the endeavours of a single generation”. With regard to high speed, increase in altitude of flight does not necessarily mean an increase in speed, but depends largely upon the supercharging of the engine. Increase of altitude has also other detrimental effects, for example, increase of drag coefficient due to decrease of Reynolds' number, and increase in induced drag due to the increase in incidence when flying near the ‘ceiling’. Actual increase in the size of aircraft would raise the speed; but not beyond a certain point, unless more engine power can be got from a given space, or some means found of reducing the drag by changing the turbulent flow to a laminar one. Progress along these lines will soon bring us to the most formidable obstacle of all, namely, the compressibility of the air as the speed of sound is approached; and this Mr. Wimperis regards as being well above the limit obtainable with engines of the type in use to-day, which he placed as between 500 and 600 m.p.h.
Article PDF
Rights and permissions
About this article
Cite this article
Natural Limits of Human Flight. Nature 139, 874 (1937). https://doi.org/10.1038/139874a0
Issue Date:
DOI: https://doi.org/10.1038/139874a0