THE AUTO-GYRO “INFERIORITY" TO AEROPLANE

Evening Star, Issue 20135, 27 March 1929, Page 6

THE AUTO-GYRO

“INFERIORITY" TO AEROPLANE

“ .It would appear Ilia I the performance of n. gyroplane is inferior to that of a corresponding aeroplane, but die gyroplane possesses valuable cna! ties of stability at large angles of ineiclence and of ease, of landing.'’ This is 1 lio considered judgment on the capabilities of the autogyro given in an Air Ministry publication '.'he'll summaries the results of experimental and theoretical investigations on the part of the .Aeronautical Research Committee, says the ‘ 'Daily Telegraph.’ The. Director of Scientific ’Research ' the Air Ministry, who presents the report, says that, in general, the performance of a gyroplane, as revealed be flight tests, is comparable viih that which would be predicted by the application of the, theory. “ Performance,” he continues, “is inferior to that of the corresponding aeroplane, of the same weight and horse-power as regards speed, rate ol climb, and distance to take-off. The gyroplane is able to land more slowly and to puli up more quickly alter landing, and, in contrast to an aeroplane of conventional design, remains stable at large angles of incidence. The only point which remains uncertain is the capacity of a gyroplane to descend vertically at n low speed, lint the practical importance of this question should not be exaggerated since the actual gliding descent at an inclination of dOdeg to the horizontal would iin ply the possibility of vertical descent whenever the wind speed exceeded twentv miles per hour.” The outstanding merit of tlie autogyro, the director says, is its “ high maximum lift co-efficient. - ’ Moreover. he adds. “ there is no loss ol si ability such as occurs when an aeroplane stalls, and a gyrophane remains completely stable at all angles of incidence. A gyrophane designed to give a moderate rate ol vertical descent should therefore have a degree of safety unattainable by an aeroplane wren with automatic slots. (In the other hand, it should ho possible by the use of slots and Haps, to construct an aeroplane whoe landing speed would lie nearly as low as that ol a. type of gyroplane. " “ According to the, model tests, the forward speed of a gvroplane. corresponding to the maximum lift-drag ratio of the wind-mill, is at least lour tinios the stalling speed, while for a typical aeroplane, the corresponding speed ratio is less than two. On the other hand. the. maximum _ observed lift-drag ratio of the wind-mill is 7}--i.e., less than half that ol a typical aeroplane wing system. 11 If a gyroplane could lie designed with a top speed ol lour times its stalling speed, it would appear that the mind-mill of the gyroplane would |j> as efficient at to]) speed as the wings of a biplane with the same stalling "speed. At lower speeds the gyroplane becomes progressively bvs efficient, since its lilt-drag ratio decreases while that of the aeroplane increases at first. The fundamental reason for this loss of efficiency of a gyroplain? lias been cxplanofl by Jtairstow as being due to the progressively greater distance travelled by the. blade elements. .It follows also that the rate of climb of a gyroplane will always be Jess than that of the corresponding aeroplane.”