In the late 1920s and early 1930s, when the P.11 was designed, the vogue for fighter design was for a machine for close-in dog-fighting. The emphasis was on manoeuvrability; speed, range and altitude were of secondary importance.
The P.11 was extremely manoeuvrable. Low wing loading (about half that of a Bf 109) that characterised the P.11 was due to large wing area and low weight. This, and large diameter wheels, made it easy to operate from unprepared auxiliary airfields expected to be used in time of war. Takeoff run was short and the aircraft accelerated rapidly, processing a good rate of climb. At low speeds the aircraft was stable and easy to manoeuvre, its landing approach very steady.
Very tight turns could be made without fear of stalling. The high strength of the wings allowed for very steep dives and rapid recovery, even exceeding the pilot's ability to tolerate the acceleration forces in the dive. In a dive the aircraft could be accelerated without restrictions, its speed only limited by air resistance, Polish pilots quickly became accustomed to these attributes.
The forward and upward visibility from the cockpit in all directions was excellent due to the gull-wing design. The only problem was that the wide fuselage obstructed the view directly below, easily overcome by rocking the aircraft from side to side.
Warren Eberspacher designed, built and flew a 66% scale replica of the PZL P.11 which was flown at the 1990 Experimental Aircraft Association Flyin. Eberspacher gained a firsthand appreciation of why Polish pilots loved the P.11 when test flying the prototype.
"Taxiing on the ground was blind and required S-turns to se ahead around the radial cowling. But as soon as the tail came up on takeoff, forward visibility was excellent."
"In the air, forward and upward visibility was unobstructed and outstanding, and it ws quite a sensation looking between the gull wings as you flew and manoeuvred. You had excellent visibility straight down and aft, and rolling the wing up also gave you excellent downward and forward visibility. A rear-view mirror kept your tail cleared."
"The aircraft handled easily and effortlessly, even in its scaled down and structurally modified form, and was a joy to fly."
The exact number of kills attained by the gull-winged fighters is still unresolved. The most cited number, 126 aerial victories, was arrived at by a commission set up in 1945 in Great Britain to study the performance of the Polish Air Force during the September Campaign. A number of more recent re-evaluations of combat reports and pilot's claims give slight smaller numbers, but it is certain to say they shot down about 100 Luftwaffe aircraft and at least three Soviet fighters.
The P.11 was able to operate from improvised airfields, withstand much punishment, and even evade Luftwaffe fighters in a dogfight due to their great manoeuvrability. However, most of its victims were slow reconnaissance aircraft or bombers. Tactics varied but were mostly based on ambushes when fighters would cruise aloft hoping to shoot down any German airplanes flying nearby.