The PZL P.11a (the so-called eleven) is a Polish, single-engine fighter plane with a metal structure with Puławski wings, a classic tail and a fixed landing gear. The flight of the prototype took place in 1931, but serial production continued in 1937-1939. The first serial version is the PZL P.11a powered by the Bristol Mercury IV S2 engine with a power of 550 HP. However, it was treated as a transitional version and only 50 were ordered. The most famous version of the "eleven" - PZL P.11c - appeared in the summer. It had an improved fuselage, wings and a vertical stabilizer. It all improved the aerodynamics of the plane. The drive unit has not changed. The interest in the construction was expressed by, among others, Romania, where 95 units of the licensed PZL P.11 were manufactured at the IAR plants. At the outbreak of the war, all versions of the P.11 were much slower than their German opponents, but at the same time had greater maneuverability, high rate of climb and a less emergency engine than German planes. They had many victories over the enemy during the September campaign, mainly as part of the Pursuit Brigade. Technical data (version P.11c): length: 7.55m, wingspan: 10.72m, height: 2.85m, maximum speed: 367km / h, rate of climb: 14.5m / s, maximum ceiling: 8000m, range maximum: 550 km, armament: fixed - 2 machine guns wz.33 cal.7.92 mm.