The P.Z.L. P.38 Wilk (Wolf) was a design for a combined fighter, attack aircraft, and dive bomber that only reached the prototype stage before the German invasion of Poland in 1939.
The P.38 was developed in response to a very ambitious requirement from the Polish Department of Aeronautics for a twin engine two-seat fighter and dive bomber that could replace the existing P.Z.L. P.11 gull wing fighter in the Fighter squadrons of the Polish Air Force and also equip a new Attack wing, where it would act as a dive-bomber, anti-tank weapon and ground attack aircraft. Although this combination of abilities seemed somewhat over-ambitious at the time, the exact same role would eventually be filled by the fighter bomber, with aircraft such as the P-47 Thunderbolt, Hawker Typhoon and Focke-Wulf Fw 190 performing those roles perfectly well.
P.Z.L. held an internal design contest to try and fill the new requirement, and eventually selected a design produced by Jerzy Dabrowski and Franciszek Misztal. This was based on Dabrowski’s twin-engined P.37 Los design, but reduced in size by about one third. Work on the P.38 was led by Misztal.
The resulting aircraft was a low wing twin engined monoplane, of all metal construction, with a stressed skin construction. It was to be powered by the Polish built P.Z.L. Foka (Seal) 8-cylinder inverted V air cooled engine, although the Hispano-Suiza 12L was considered as an alternative. Like the P.37 it had a narrow fuselage with an oval cross section. It carried a crew of two, half that of the P.37.
In 1936 the plan was for two different versions were to be built. The P.39 was to be a low level dive-bomber and strike/ interceptor fighter. This was to replace the P.11 in fifteen fighter squadrons in 1939, and equip two new squadrons in 1940. The P.38 was to be the high altitude attack aircraft and escort fighter, and was to equip ten new attack squadrons in 1939. This was to rise to 32 P.38 squadrons, and in 1941 it was also to replace the P.23 Karas in the ‘liniowe’ or ‘front line’ squadrons.
Towards the end of 1936 the plan to use the P.38/ P.39 as a normal fighter was abandoned, and work began on the single seat single engine P.50 Jastrzab. The P.39 designation was also dropped, and all versions of the new design became the P.38. In October 1936 it was decided to form ten P.38 attack squadrons, each with ten front line aircraft and ten reserves. These were to be dive bomber and attack squadrons with the ability to operate as emergency fighter squadrons if needed.
Work on detailed drawings for the attack fighter version began early in 1936, and work on two prototypes and a static test airframe started in the spring of 1936. A decision on which engine to use was to be made before the end of 1936 and large scale production begin late in 1937. The P.38A attack fighter was to be armed with two fixed 20mm cannon and two 7.7mm machine guns in the nose, two retractable 7.7mm machine guns in the rear cockpit and carry a 661lb bomb under the fuselage.
The big weakness in the design was the Foka engine. This was an 8-cylinder inverted V air cooled engine that was being developed by Stanislaw Nowkunski from an earlier design for a 4-cylinder engine that had never been built. However Nowkunski was killed in a climbing accident in 1936 when the engine was still at a very early stage of development. When the first Foka was tested it proved to be under-pwered and rather unreliable, and never reached the point where it could be used in flight.
As a result a new engine had to be found for the P.38. The Foka would have been a very small engine for the amount of power it was due to produce, and it proved to be difficult to find an alternative. The American Ranger inline V engine and the Gnome-Rhone 14M Mars double row radial were both considered.
In the end both would be used. The Gnome-Rhone engine was selected for the main production version of the aircraft, which became the P.Z.L. P.48 Lampart (Leopard), while the Ranger engine was to be used to test the second prototype of the P.38.
Both prototypes had been completed by the middle of 1937 and were now waiting for engines.
The first prototype, P.38/I, was given two non-flying Foka I engines and sent to the Paris Salon de l’Aeronautique late in 1938. After its return to Poland it was equipped with the Foka II, which had finally emerged as a reasonably reliable engine, providing 420hp normally and 620hp at take off. The prototype began flight trials with the Foka II in January 1939. However the Foka II didn’t enter production, so this was a dead-end.
The second prototype, P.38/II, was given two 450hp Ranger SGV-770B twelve-cylinder supercharged inverted V engines. It eventually made its maiden flight in May 1938, and was used extensively for testing.
When the Germans invaded the two prototypes were the only examples of the P.38 that had been built.
Work on the P.48 Lambert was also delayed by the problems with the Foka engine. Its design had been completed by the start of 1938, but the Polish Aviation Command hadn’t then decided to scrap the Foka, so postponed making any decision on the P.48 until the end of the year.
Engine: Foka II
Power: 420hp/ 620hp at take off
Span: 36ft 3in
Length: 27ft 5in
Height: 8ft 2.75in
Empty Weight: 3,780lb
Loaded weight: 6,107lb
Maximum Speed: 288.9mph at 13,123ft
Cruising Speed: 248.5mph at sea level
Range: 776 miles
Guns: Two fixed 20mm cannon and two 7.7mm machine guns in the nose, two retractable 7.7mm machine guns in the rear cockpit
Bomb load: 661lb bomb under fuselage