PZL.43. The PZL.43 was a Polish light bomber and reconnaissance aircraft designed in the mid-1930s by PZL in Warsaw. It was a development of the PZL.23 Karaś. Its main user was the Bulgarian Airforce who called it the Chaika (Чайка, gull).

Design and development
The standard Polish light bomber and reconnaissance aircraft, the PZL.23 Karaś could not be exported because of licence restrictions on the use of the Polish-built (PZL) Bristol Pegasus engine.  The PZL.43 was a development of the PZL.23, powered instead by a Gnome-Rhône 14K engine. It was first offered to Romania, but they rejected it in favour of domestic designs. The PZL was more successful in Bulgaria, then reforming their airforce after a period of post-World War I treaty constraints. An order for 12 aircraft was placed in April 1936.

Like its predecessor, the PZL.43 was conventional in layout, a low-wing, all-metal, metal-covered cantilever monoplane. The fuselage was semi-monocoque. It had a crew of three: pilot, bombardier and an observer/rear gunner. The pilot and observer's cockpits were in tandem and glazed with the open rear gunner's position behind.  The bombardier occupied a ventral combat gondola which had a machine gun position at the rear. The fixed undercarriage was heavily  spatted, though not suited for rough airfields. Tanks in the centre section of the wings held 740 litres of fuel. A three-bladed propeller was used.
 
The differences between the two types derived chiefly from use of the heavier and longer (two rows of seven cylinders) Gnome-Rhône engine. To maintain the centre of gravity the fuselage was lengthened by adding one central section which moved the bombardier's gondola rearwards. The new engine improved performance considerably, for example increasing maximum speed from 319 km/h to 365 km/h. In addition, armament was increased with two forward firing wz. 36 machine guns mounted in offset fairings to clear the radial engine. Up to 700 kg of bombs could be carried under the wings, like the PZL.23. A common option was 24 x 12.5 kg bombs (300 kg in total). A camera was fitted for reconnaissance.

No prototype preceded the production series of 12 aircraft completed in 1937. These were designated PZL.43 and powered by Gnome-Rhône 14Kirs engines of 900 to 930 hp (671 to 694 kW).

In March 1938, Bulgaria ordered a further 42 aircraft powered by the new Gnome-Rhône 14N-01 engine, an improved 14K design that delivered 950 to 1,020 hp (708 to 761 kW). These were designated PZL.43A. Production started in 1939, but only 36 were completed and delivered to Bulgaria before the German Invasion of Poland in September 1939.

Sometimes the aircraft is called the "PZL P.43", but despite an abbreviation P.43 painted on the tail fin, the letter "P" was used mainly for fighter designs (like the PZL P.11). In some older sources the PZL.43 is referred to as the PZL.43A, and the PZL.43A as the PZL.43B. These latter designations are incorrect.

Operational history
After the German invasion of Czechoslovakia in March 1939, in an increasingly tense political situation, the Polish Air Force proposed to requisition from the Bulgarian order of PZL.43As. A short-sighted decision by the military authorities, afraid of penalties, was to fulfill the order (the penalties would have been less than the worth of two aircraft - about 440,000 zlotys). The first PZL.43As were delivered to Bulgaria in June 1939, the last of 36 in August, just before World War II began. Along with 12 PZL.43s and two PZL.43As delivered by Germany in 1940, these gave Bulgaria a total of 50 aircraft.

They initially served in three 12-aircraft squadrons of the 1st Line Group (linyen orlyak). From 1942 they were used in the 1st Reconnaissance Regiment and 2nd Line Regiment. Chaikas were used mostly for training and searching for partisans in Macedonia in 1943–44. Several of them crashed during service and there were difficulties in obtaining spare parts. In 1944 they were withdrawn from combat service and were eventually written off in 1946.

At the time of the German invasion of Poland, nine PLZ.43As of the Bulgarian order were crated ready for delivery or were incomplete, two lacking propellers. Five were moved to the airfield at Bielany and taken over by the Polish Air Force for use by 41 Eskadra Rozpoznawcza (41st Reconnaissance Squadron) which was mostly equipped with PZL.23 Karaś. They undertook reconnaissance duties but by 10 September 1939, there were the only two aircraft remaining. One was shot down by a Messerschmitt Bf 110 at Michałówek near Sulejówek and the crew killed. The second, damaged by a pair of Messerschmitt Bf 109s, two days later, crash landed in Brześć. Both probably still carried Bulgarian markings.

Another three complete aircraft from the Bulgarian order were left at Okęcie and these were damaged during an air raid on 4 September and later captured by the Germans in a factory in Warszawa-Okęcie. Some damaged aircraft left at Okęcie airfield were captured by the Germans. Five were repaired and delivered to Bulgaria. Another was tested by the Germans in Rechlin in 1940 before joining the others in Bulgaria in October.

Variants
PZL.43
First production series, 12 built.
PZL.43A
Second production series with more powerful Gnome-Rhône 14N-01 engine, 42 built.
PZL.43B
Improved version, powered by a 980 hp (731 kW) Gnome-Rhône 14N-01 engine.

Operators

Bulgarian Air Force operated 50 aircraft
2. jato/ Obrazcow Orliak (2. Squadron of the Exemplary Wing) operated 12 PZL.43
1. Lineen Orliak (Level-flight (bomber) Squadron) operated 36 PZL.43A, 12 in each jato (Squadron)
1. Razuznawatelen Polk (Reconnaissance Regiment) operated PZL.43A between March 1942 and August 1944
2. Lineen Polk (Level-flight (bomber) Regiment) operated PZL.43A between March 1942 and August 1944
113. jato za blisko razuznavanye (Close Distance Reconnaissance Squadron) operated 13 PZL.43A between August 1944 and early 1945
123. jato za blisko razuznavanye operated 11 PZL.43A between August 1944 and early 1945 

 Luftwaffe tested captured aircraft.

Polish Air Force
41 Eskadra Rozpoznawcza (Reconnaissance Squadron)  operated five PZL.43A aircraft

Specifications (PZL.43B)

See also

References

Notes

Further reading

External links

PZL aircraft
1930s Polish bomber aircraft
1930s Polish military reconnaissance aircraft
Single-engined tractor aircraft
Low-wing aircraft
Aircraft first flown in 1937
Aircraft with fixed conventional landing gear