11/30/2007. Remarks by Bernhard Klein: "The D.27 was designed by Émile Dewoitine to meet a French requirement of 1926 for a lightweight fighter. In January 1927 the Constructions Aéronautiques Émile Dewoitine was liquidated and the design was transferred to the EKW (Eidgenössische Konstruktions Werkstatte, Federal Constructions Workshop) in Thun, Switserland.
The prototype was flown on June 3, 1928, and in the autumn a pre-series of twelve aircraft was set up by EKW. Three D.27s were sold to Romania, three to Yugoslavia and one to Argentina, while the remaining aircraft went to France where Émile Dewoitine had established the Société Aéronautique Française-Avions Dewoitine in March 1928.
After testing, the Swiss AF selected the D.27 as their new fighter and bought the prototype. A pre-series of five aircraft, designated D.27 III, was ordered from EKW, and additional contracts were placed for 15 D.27 IIIRs (interceptor fighter) and 45 D.27 IIIs. The D.27 III was powered by a 500 hp Hispano-Suiza HS-57 12-Mb 12-cylinder V-engine, the D.27 IIIR by a 570 hp Hispano-Suiza HS-57 12-Mc, The HS-57 12-Mc engines were developing many problems and all D.27 IIIRs were re-engined to D.27 III standard. The D.27 III were fitted with two synchronized .303 in (7.7 mm) machine-guns.
The D.27 III served with the Swiss AF from 1931 to 1944. In mid 1939, with the threat of war looming over Europe, private aviation was shut down and the all-silver D.27 IIIs received a kind of camouflage scheme, while in 1940 they were regulated to secondary roles."