03/31/2012. Remarks by Johan Visschedijk: "The Armadillo, designed by F. Murphy (hence the F.M. in the designation) who had succeeded Frits Koolhoven as chief designer to Armstrong Whitworth, was initiated late in 1917, and the construction of two prototypes began early in 1918 as a private venture, the first of these being flown in April of that year. The two Armadillo's were serialed X19 and X20 in the Licensed Series.

Powered by a 230 hp Bentley B.R.2 nine-cylinder rotary, the Armadillo had provision for an armament of two synchronized 0.303 in (7.7 mm) Vickers machine guns, but flying characteristics were declared to be most unsatisfactory and flight testing was terminated in June 1918, the second prototype never being flown."