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).

P.Grosz, G.Haddow, P.Shiemer Austro-Hungarian Army Aircraft of World War One (Flying Machines)

Phonix 20.24 and 20.25

  During the winter of 1917, Kirste began design work on a high-performance fighter that represented the "total experience gathered by the aircraft industry during the war." The drawings and specifications were approved by Flars in January 1918. Two prototypes, known as the "Kirste fighters," were built. The 20.24 was powered by a 230 hp Hiero engine and fitted with a new rib section. The 20.25, powered by a 225 hp Daimler engine, retained the D.II rib section and had a slightly larger fin. By ingenious design, Kirste extracted maximum strength from a light and simple airframe. The oval, veneer-covered fuselage, the wide center section and narrow lower wing gave the pilot a superb field of view. An unusual feature was a fire-proof fuel tank mounted between pilot and engine. The prototypes, completed in May, were flight tested in June 1918.
  The 20.24 and 20.25 appeared at the Fighter Evaluation on the last day (13 July) and were available for inspection only because they were not completely ready. Oberleutnant Fiala commended the electrical reflex sight on 20.24 and suggested minor internal changes. According to Phonix records, had the fighter gone into production it would have been designated Phonix D.IV. The prototypes arrived too late to be included in the 31 August 1918 production calendar. Both prototypes were accepted in October 1918 to permit Phonix to receive payment for the aircraft.

Phonix 20.24 Specifications
Engine: 230 hp Hiero
Wing: Span Upper 8.50 m (27.89 ft)
Span Lower 7.50 m (24.61 ft)
Chord Upper 1.50 m (4.92 ft)
Chord Lower 1.50 m (4.92 ft)
Dihedral Upper 0 deg
Dihedral Lower 0 deg
Sweepback Upper 0 deg
Sweepback Lower 0 deg
Gap 1.65 m (5.41 ft)
Stagger 0.71 m (2.33 ft)
Total Wing Area 23.50 sq m (253 sq ft)
General: Length 6.60 m (21.65 ft)
Height 2.70 m (8.86 ft)
Track 1.40 m (4.59 ft)
Empty Weight 665 kg (1466 lb)
Loaded Weight 950 kg (2095 lb)
Maximum Speed: 185 km/hr (115 mph)
Climb: 1000m (3,281 ft) in 2 min 10 sec
5000m (16,405 ft) in 18 min

E.Hauke, W.Schroeder, B.Totschinger Die Flugzeuge der k.u.k. Luftfahrtruppe und Seeflieger 1914-1918

20. Flugzeuge der Phönix-Flugzeugwerke, vormals Österr. Albatros
20.24 Phönix D Prototyp für Ba D.IV H 230
20.25 Phönix D Prototyp für Ba D.IV Dm 225