Page:Aircraft in Warfare (1916).djvu/38

§ 3 well understood; in the case of the former the resistance is approximated by a curve a a. Fig. 1, representing the sum of a resistance following the V-square law and a constant; the latter (the dirigible) may be taken as following the V-square law implicitly. Fig. 1, b b.



Fig. 1 represents approximately actual values of the resistance coefficients, in tractive effort per cent., in machines of average size as they exist to day, for the speeds given in miles per hour.

One salient fact is at once evident; the greater the horse-power available for a given engine weight the greater the advantage in the matter of speed in favour of the aeroplane; the highest speed of flight of an aeroplane attained to-day (through, i.e., relatively to, the air) is already more than twice that of which