W.Green, G.Swanborough The Complete Book of Fighters

PHONIX 20.22 TO 20.25 Austria-Hungary

   During the Fighter Evaluation held at Aspern in July 1918, Phonix submitted (in addition to the previously-mentioned D IIa 422.23) two modified D Ila fighters, the 230 hp Hiero-powered 20.22 and the 225 hp Austro-Daimler-powered 20.23. These differed from the standard D IIa fundamentally in having ailerons on both upper and lower wings. In addition, the upper wing was marginally raised, that of the 20.22 being increased slightly in area and combined with a reduced-span lower wing. Whereas 20.22 had struts interconnecting the ailerons, 20.23 had aileron cables running through the lower wing. Neither type was pursued further, but two additional Phonix prototypes participated in the evaluation. These, the 20.24 and 20.25, were representative of an entirely new design, whereas the 20.22 and 20.23 had, like all preceding Phonix fighters, stemmed from the Brandenburg D I. The 20.24 and 20.25 differed one from the other in engine type, the former having a 230 hp Hiero and the latter a 225 hp Austro-Daimler. Single-bay staggered biplanes with oval-section plywood-skinned fuselages, they were designed by Dipl-Ing Kirste assisted by Ing Zwerina and were flown only on the last day of the Fighter Evaluation (13 July). Demonstrating outstanding qualities, they were recipients of an order for two pre-series prototypes (20.28 and 20.29) in anticipation of series production as the Phonix D IV. Hostilities terminated, however, before these could be completed. The following data relate to the Hiero-powered 20.24.

Max speed, 115 mph (185 km/h).
Time to 3,280 ft (1 000m), 2.0 min.
Empty weight, 1,466 lb (665 kg).
Loaded weight, 2,094 lb (950 kg).
Span, 27 ft 10 2/3 in (8,50 m).
Length, 21ft 7 4/5 in (6,60 m).
Height, 9 ft 6 1/8 in (2,90 m).
Wing area, 252.96 sq ft (23,50 m2).