The Phönix D.I was the second design developed by the Phönix Flugzeug-Werke based on Hansa-Brandenburg designs which it has produced under licence. The D.I was a single-seat biplane fighter with improvements over the original Hansa-Brandenburg design which included more efficient wings, a more powerful engine and structural improvements. A prototype was first flown in 1917 and proved to be fast but difficult to handle but because of the urgent need for fighters the D.I entered production. To improve the problems a modified variant, the D.II was introduced with balanced elevators and balanced ailerons on the upper wings. A further development was the D.III which had balanced ailerons on both wings and a more powerful 230 hp (172 kW) Hiero in-line engine. The last of 158 aircraft of all three types was delivered on 4 November 1918.