The first fighter of indigenous Polish design, the P.1 produced by the Paristwowe Zaklady Lotnicze (P.Z.L.), or National Aviation Establishment, embodied several technical innovations. Designed by Zygmunt Pulawski, the P.1 was of all-metal construction, its most novel feature being the "gulling" into the fuselage of the centre section of the high wing, thus eliminating the normal cabane. This both reduced drag and improved the forward view for the pilot. Powered by a 12-cylinder water-cooled Hispano-Suiza 12 Lb Vee-type engine affording 630hp for take-off, the first prototype, the P.1/I, was flown on 25 September 1929. Armament comprised two 7.7mm Vickers machine guns. The second prototype, the P.1/II, featured a repositioned radiator bath and redesigned vertical tail surfaces, and joined the test programme in March 1930. Further development was discontinued in favour of radial-engined variants, as the Polish air arm, the Lotnictwo Wojskowe, was biased against liquid-cooled engines.

3-View

A three-view drawing of PZL P.1/I (1278 x 830)