The D XXIII single-seat fighter push-pull prototype was powered by two 528hp Walter Sagitta I-SR engines and flying for the first time on 30 May 1939. Proving an attrac-tion at the 1938 Paris Air Show, the maximum speed was 520 kph.
Versions of the D XXIII were also proposed with Hispano- Suiza 12Xcrs, Junkers Jumo 210G and Rolls-Royce Kestrel XV engines, and although all-metal construction was intended, the prototype was fitted with a wooden wing of greater thickness/chord ratio in order to expedite the test programme. Owing to various problems, including rear engine cooling, only four hours of flight testing had been completed when the invasion of the Netherlands brought the D XXIII development programme to a halt. The proposed armament comprised two 7.9mm and two 13.2mm FN-Browning machine guns.
Engines: two 528hp Walter Sagitta I-SR
Max take-off weight: 2950 kg
Empty weight: 2180 kg / 4806 lb
Wingspan: 11.50 m / 37 ft 9 in
Length: 10.20 m / 33 ft 6 in
Height: 3.80 m / 12 ft 6 in
Wing area: 18.50 sq.m / 199.13 sq ft
Max. speed: 525 km/h / 326 mph
Cruise speed: 390 km/h / 242 mph