Spratt 103


The aerodynamic formula used (the simplest and safest existing), which could be called “articulated or pivoted wings”, has been all but ignored or forgotten by most aeronautical specialists. Yet it is, paradoxically, one of the oldest manners of flying, even recommended by Octave Chanute (known as “the Father of Aviation”) in 1902 and, finally, nearest to that of the birds, which fly regularly in turbulent air conditions and yet never stall or get into spins.

Let us recall some achievements of aircraft using the principle of “articulated / pivoted wings”:

(Clic on pictures to read details)



1914 : Louis de Monge modifies a “De Perdussin” airplane : Wings have (using springs) variable and elastically variable incidences, absorbing gust loads
1929 : Henri Mignet, designer of the Pou de Ciel (“Flying Flea”), tests also the system of the “pivoting wings” with the HM2, HM6 and the HM9, inspired in that by the sailplane of Harth Messerschmitt, which had already successfully used this device

1936 : Marcel Leyat, after various prototypes, constructs the Hélica (manufacturer and pilot: Andre Jacquemin)

1939 : George G. Spratt designs and builds the “Spratt 107”, a seaplane called also the “Controlwing”


1974 : George G. Spratt designs and builds the “Spratt 105”, a terrestrial version of the “Controlwing”

1983 : George Briffaud designs and builds the GB 10 “Flying Flea”. As he recalls,”The roll control by differential pivoting of the front wings was very satisfactory, with a total absence of adverse yaw.”


1990 : The Freewing company produces different prototypes (based on the design work carried out by George G. Spratt), then specializes in the market of military drones