kits of pre war polish aircraft
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So you have been breathing in the glue.Any visions?
No visions, just dreams (nightmares?) about unfinished models, that I'm just a few fiddly bits away from finishing, but never seem to finish. Just like in real life!
Venganza
- Thread starter
- #23
thanks antoni that will be very helpfull when i assemble the kit
From Polish Aircraft 1893-1939 Jerzy B Cynk
PZL P.50 Jastrząb
Shrouded in a heavy veil of official secrecy, not allowed to be photographed or even mentioned in the Polish pre-war press, the P.50 Jastrząb is even today something of a mystery. Its short career was rather confusing. In spite of tight security surrounding the project, the fighter was shown to a German ally, the Italian Foreign Minister, Count Galeazzo Ciano the P.50 Jastrząb who visited Warsaw at the end of February 1939; it was ordered into large-scale production off the drawing-board, only to be cancelled a few months before the outbreak of war ; and assessments of its capabilities, put forward during investigations into the reasons for the Lotnictwo Wojskowe's weakness in September 1939, conducted by the Polish Government in exile, were contradictory and biased. When the war ended it became evident that most official P.Z.L. documents had been lost, and only provisional general arrangement drawings of the Jastrząb and a few poor photographs showing small fragments of the aircraft appear to have survived.
The following objective account of the Jastrząb story is based on a critical study of all the available evidence and exclusive interviews with former P.Z.L. and Lotnictwo Wojskowe personnel.
In the second half of 1936, when far-reaching decisions regarding the future of the Lotnictwo Wojskowe were being taken by the Government and Aviation Command, the earlier plan to replace completely the P.11 with the P.39 twin-engined two-seat strike fighter was abandoned and the view was endorsed that the Polish fighter force should be armed with a highly manoeuvrable single-engined single-seat 'hunter' fighter, designed for dog-fighting and intended for the close defence of specific targets, and that the fast long-range twin-engined machine (eventually known as the P.38 Wilk), which could chase enemy raiders over the whole country, would be used only in the complementary capacity.
The P.24 was briefly considered for the former role, but as this model could offer only a marginal improvement over the P.11, the Aviation Command favoured a more progressive design, and in the autumn of 1936 Wsiewołod Jakimiuk, head of the P.Z.L. fighter team, put forward proposals for an advanced low-wing monoplane which offered improved all-round performance and great scope for future development. Rather than develop the fighter as a further projection of the P.11/P.24 line with a low cantilever wing (as the Rumanians did with the LA.R.80j81, which was broadly a low-wing derivative of the P.Z.L. P.24), Jakimiuk, profoundly influenced by American design philosophy and, in particular, the Seversky monoplanes, created a design easily adaptable to take bigger engines, which bore some resemblance to the Seversky machines. This aircraft, number 50 in the P.Z.L. designation sequence, and Korsak's competitive PA5 study for a light-weight interceptor, became the final contenders to the hunter fighter requirement, and the former was approved in preference to the latter for immediate development.
The P.50 was named Jastrząb (Hawk) and a full interceptor specification was written around the study by the Aviation Command working in collaboration with the LT.L. In view of the lack of time (due to the earlier official interest in the P.39 two years had already been lost in the fighter development programme), it was decided to use a lower-powered but well proven and established engine, and the 840 hp Mercury VIII was selected to power the first production variant, the P.50A Jastrząb A, the estimated top speed of 500 kmh (310•6 mph) at 4,300 m (14,107 ft) for the Mercury VIII powered model being considered adequate for target-defence purposes, and four wing-mounted 7•7 mm machine-guns were specified as the basic armament. The detailed design and a mock-up were approved in the autumn of 1937, and construction of a static-test airframe and two prototypes-the P.50jI Jastrząb I, designed to take radials of up to 1,200 hp and generally corresponding to the Jastrząb A, and the P.50jII Jastrząb II, stressed for radial engines of up to 1,600 hp and much more in line with Jakimiuk's original intentions-began at the W.P.l plant.
Meanwhile the XVIIth Session of the K.S.D.S., sitting in October 1936, approved the four-year Lotnictwo Wojskowe expansion programme, to be completed by 31 March, 1941, which called among other things for 15 squadrons of single-seat interceptors with ten aircraft per squadron and 100 per cent reserve. In view of this and the quickly deteriorating equipment situation in the fighter field, the Aviation Command ordered 300 Jastrząb As off the drawing-board, paying for the first 100 in advance in 1938, delivery of the first 50 being expected by September 1939. At the same time the P.Z.L. W.S.1 at Okęcie received production contracts for 450 Mercury VIII engines. To speed up the P.50 programme the British Dowty company was given an order for an inwardly-retracting undercarriage for the P.50jI prototype, while the P.Z.L.-designed Avia-manufactured gear was being evolved for the production model. Unfortunately the Dowty undercarriage equipment arrived over four months late, and the Jastrząb I, completed in September 1938 and fitted with the Bristol-built 810-840 hp Mercury VIII engine (No. M42l02, despatched to Poland on 28 July, 1938), could not fly until the following February.
The flight trials conducted by Maj Bolesław Orlinski, the factory's chief test pilot, were not entirely encouraging. The Jastrząb, flown with the Bristol and P.Z.L. Mercury VIIIs, proved too massive an aircraft for the specified engine; 'rate of climb was poor and the top speed in the fully loaded condition was only 442 kmjh (274-4 mph). The aircraft was unstable in low-speed turns and tail-flutter developed at the other end of the speed scale. Modifications were put in hand, but during the second phase of trials in April, Orlinski reported that further major improvements would be necessary. A puzzling aspect of the trials was the fact that none of the engines fitted to the P.50jI airframe developed full power, and it was not until May when a young engineer, looking at the prototype, was suddenly struck by the thought that the carburettor air intake was too small. He was soon proved to be right. As it turned out, the intake was taken from an engine of another type and its suitability for the Mercury installation was never examined. In the early summer the machine was provided with an enlarged air intake and this, combined with changes introduced to the tail unit and wing/fuselage fillets, resulted in considerably improved performance and handling characteristics. In August the P.50/I exceeded a speed of 500 km/h (310'6 mph) in level flight, but by the outbreak of war the LT.L.airworthiness tests had not been entirely completed and Service acceptance trials, conducted by the Experimental Wing attached to the LT.L., had not begun.
The much more potent P.50/II airframe, substantially differing from that of the Jastrząb I, had been completed in the spring of 1939 and was waiting for an engine. The machine, featuring an all-round-vision hood and slimmer rear fuselage, had provision for additional fuel tanks and for a 300 kg (661Ib) bomb under the fuselage for dive-bombing or attack duties. The pilot's seat was protected by heavy armour-plate, and the fixed armament comprised two 20 mm cannon in the wing roots in addition to the four wing-mounted machine-guns. The new indigenous P.Z.L. Waran (an African lizard) radial, rated at 1,200-1,400 hp, was to supply the power, and the fighter's guaranteed performance included a maximum speed of 560 km/h (347'9 mph). Unfortunately, development of the War an was behind schedule and in the summer of 1939 there was little prospect of the engine being available for installation before the middle of 1940. In the search for a solution to the powerplant problem a number of other engines were considered, and the 1,375 hp Bristol Hercules and the 1,400 hp Gnome Rhone 14N50 series radials were selected as suitable alternatives. It seems that the decision to test the P.50jII with the Hercules was taken, and in view of structural differences between the Jastrząb II and the Jastrząb A, a new factory designation is believed to have been allocated to the design in the final weeks before the outbreak of war.
In the second half of 1938, with Gen Zając's critical re-appraisal of the Air Force's re-equipment prospects and mounting opposition to Gen Rayski's unreserved faith in the concept of a radial-powered fighter, the possibility of purchasing the manufacturing rights for the powerful Hispano-Suiza liquid-cooled vee engines began to be explored. Anticipating events, Jakimiuk began initial work on a projection of the basic Jastrząb design adapted for such a powerplant. Proposals involving the use of the 1,000-1,200 hp Hispano-Suiza 12Y, and, later, the brand-new 1,400-1,600 hp 12Z engine, studied in the winter of 1938-39 and the following spring, were covered by the designation P.56 Kania (Kite). However, Dąbrowski's competitive design (believed to have been the P.62) became the subject of a development contract and the Kania project is thought to have been cancelled in the summer.
PZL P.50 Jastrząb
Shrouded in a heavy veil of official secrecy, not allowed to be photographed or even mentioned in the Polish pre-war press, the P.50 Jastrząb is even today something of a mystery. Its short career was rather confusing. In spite of tight security surrounding the project, the fighter was shown to a German ally, the Italian Foreign Minister, Count Galeazzo Ciano the P.50 Jastrząb who visited Warsaw at the end of February 1939; it was ordered into large-scale production off the drawing-board, only to be cancelled a few months before the outbreak of war ; and assessments of its capabilities, put forward during investigations into the reasons for the Lotnictwo Wojskowe's weakness in September 1939, conducted by the Polish Government in exile, were contradictory and biased. When the war ended it became evident that most official P.Z.L. documents had been lost, and only provisional general arrangement drawings of the Jastrząb and a few poor photographs showing small fragments of the aircraft appear to have survived.
The following objective account of the Jastrząb story is based on a critical study of all the available evidence and exclusive interviews with former P.Z.L. and Lotnictwo Wojskowe personnel.
In the second half of 1936, when far-reaching decisions regarding the future of the Lotnictwo Wojskowe were being taken by the Government and Aviation Command, the earlier plan to replace completely the P.11 with the P.39 twin-engined two-seat strike fighter was abandoned and the view was endorsed that the Polish fighter force should be armed with a highly manoeuvrable single-engined single-seat 'hunter' fighter, designed for dog-fighting and intended for the close defence of specific targets, and that the fast long-range twin-engined machine (eventually known as the P.38 Wilk), which could chase enemy raiders over the whole country, would be used only in the complementary capacity.
The P.24 was briefly considered for the former role, but as this model could offer only a marginal improvement over the P.11, the Aviation Command favoured a more progressive design, and in the autumn of 1936 Wsiewołod Jakimiuk, head of the P.Z.L. fighter team, put forward proposals for an advanced low-wing monoplane which offered improved all-round performance and great scope for future development. Rather than develop the fighter as a further projection of the P.11/P.24 line with a low cantilever wing (as the Rumanians did with the LA.R.80j81, which was broadly a low-wing derivative of the P.Z.L. P.24), Jakimiuk, profoundly influenced by American design philosophy and, in particular, the Seversky monoplanes, created a design easily adaptable to take bigger engines, which bore some resemblance to the Seversky machines. This aircraft, number 50 in the P.Z.L. designation sequence, and Korsak's competitive PA5 study for a light-weight interceptor, became the final contenders to the hunter fighter requirement, and the former was approved in preference to the latter for immediate development.
The P.50 was named Jastrząb (Hawk) and a full interceptor specification was written around the study by the Aviation Command working in collaboration with the LT.L. In view of the lack of time (due to the earlier official interest in the P.39 two years had already been lost in the fighter development programme), it was decided to use a lower-powered but well proven and established engine, and the 840 hp Mercury VIII was selected to power the first production variant, the P.50A Jastrząb A, the estimated top speed of 500 kmh (310•6 mph) at 4,300 m (14,107 ft) for the Mercury VIII powered model being considered adequate for target-defence purposes, and four wing-mounted 7•7 mm machine-guns were specified as the basic armament. The detailed design and a mock-up were approved in the autumn of 1937, and construction of a static-test airframe and two prototypes-the P.50jI Jastrząb I, designed to take radials of up to 1,200 hp and generally corresponding to the Jastrząb A, and the P.50jII Jastrząb II, stressed for radial engines of up to 1,600 hp and much more in line with Jakimiuk's original intentions-began at the W.P.l plant.
Meanwhile the XVIIth Session of the K.S.D.S., sitting in October 1936, approved the four-year Lotnictwo Wojskowe expansion programme, to be completed by 31 March, 1941, which called among other things for 15 squadrons of single-seat interceptors with ten aircraft per squadron and 100 per cent reserve. In view of this and the quickly deteriorating equipment situation in the fighter field, the Aviation Command ordered 300 Jastrząb As off the drawing-board, paying for the first 100 in advance in 1938, delivery of the first 50 being expected by September 1939. At the same time the P.Z.L. W.S.1 at Okęcie received production contracts for 450 Mercury VIII engines. To speed up the P.50 programme the British Dowty company was given an order for an inwardly-retracting undercarriage for the P.50jI prototype, while the P.Z.L.-designed Avia-manufactured gear was being evolved for the production model. Unfortunately the Dowty undercarriage equipment arrived over four months late, and the Jastrząb I, completed in September 1938 and fitted with the Bristol-built 810-840 hp Mercury VIII engine (No. M42l02, despatched to Poland on 28 July, 1938), could not fly until the following February.
The flight trials conducted by Maj Bolesław Orlinski, the factory's chief test pilot, were not entirely encouraging. The Jastrząb, flown with the Bristol and P.Z.L. Mercury VIIIs, proved too massive an aircraft for the specified engine; 'rate of climb was poor and the top speed in the fully loaded condition was only 442 kmjh (274-4 mph). The aircraft was unstable in low-speed turns and tail-flutter developed at the other end of the speed scale. Modifications were put in hand, but during the second phase of trials in April, Orlinski reported that further major improvements would be necessary. A puzzling aspect of the trials was the fact that none of the engines fitted to the P.50jI airframe developed full power, and it was not until May when a young engineer, looking at the prototype, was suddenly struck by the thought that the carburettor air intake was too small. He was soon proved to be right. As it turned out, the intake was taken from an engine of another type and its suitability for the Mercury installation was never examined. In the early summer the machine was provided with an enlarged air intake and this, combined with changes introduced to the tail unit and wing/fuselage fillets, resulted in considerably improved performance and handling characteristics. In August the P.50/I exceeded a speed of 500 km/h (310'6 mph) in level flight, but by the outbreak of war the LT.L.airworthiness tests had not been entirely completed and Service acceptance trials, conducted by the Experimental Wing attached to the LT.L., had not begun.
The much more potent P.50/II airframe, substantially differing from that of the Jastrząb I, had been completed in the spring of 1939 and was waiting for an engine. The machine, featuring an all-round-vision hood and slimmer rear fuselage, had provision for additional fuel tanks and for a 300 kg (661Ib) bomb under the fuselage for dive-bombing or attack duties. The pilot's seat was protected by heavy armour-plate, and the fixed armament comprised two 20 mm cannon in the wing roots in addition to the four wing-mounted machine-guns. The new indigenous P.Z.L. Waran (an African lizard) radial, rated at 1,200-1,400 hp, was to supply the power, and the fighter's guaranteed performance included a maximum speed of 560 km/h (347'9 mph). Unfortunately, development of the War an was behind schedule and in the summer of 1939 there was little prospect of the engine being available for installation before the middle of 1940. In the search for a solution to the powerplant problem a number of other engines were considered, and the 1,375 hp Bristol Hercules and the 1,400 hp Gnome Rhone 14N50 series radials were selected as suitable alternatives. It seems that the decision to test the P.50jII with the Hercules was taken, and in view of structural differences between the Jastrząb II and the Jastrząb A, a new factory designation is believed to have been allocated to the design in the final weeks before the outbreak of war.
In the second half of 1938, with Gen Zając's critical re-appraisal of the Air Force's re-equipment prospects and mounting opposition to Gen Rayski's unreserved faith in the concept of a radial-powered fighter, the possibility of purchasing the manufacturing rights for the powerful Hispano-Suiza liquid-cooled vee engines began to be explored. Anticipating events, Jakimiuk began initial work on a projection of the basic Jastrząb design adapted for such a powerplant. Proposals involving the use of the 1,000-1,200 hp Hispano-Suiza 12Y, and, later, the brand-new 1,400-1,600 hp 12Z engine, studied in the winter of 1938-39 and the following spring, were covered by the designation P.56 Kania (Kite). However, Dąbrowski's competitive design (believed to have been the P.62) became the subject of a development contract and the Kania project is thought to have been cancelled in the summer.
Attachments
Continued.
On 22 March, 1939, Gen Ludomil Rayski was relieved of his duties as the C-in-C Lotnictwo Wojskowe at his own request, and Gen Józef Zając gained a great measure of control over Air Force affairs. Prejudiced against radial-powered interceptors and disappointed by the Jastrząb's early trials, which in his view had proved the machine totally unsatisfactory on the counts of speed and manoeuvrability, Zając decided to cancel the whole P.50 production programme. The newly established P.Z.L. W.P.2 plant at Mielec, which was to become the main Jastrząb production centre by the spring of 1940, immediately stopped preparations for the manufacture of the aircraft, but the W.P.1 at Okęcie, which had already laid down 30 airframes of the initial production batch, was allowed to resume work on them in the summer, when the P.50jI began to show signs of improvement. As the French armament loan opened up the possibility of large purchases of French engines, the first pre-production airframe was to be fitted with the 870 hp Gnome-Rhone 14Kirs fourteen-cylinder double-row radial to serve as a development machine for the proposed P.50B Jastrząb B variant, the aircraft being almost ready in September 1939. Moves were also made to obtain either 1,100 hp Gnome-Rhone 14K or 1,000 hp Pratt Whitney Twin Wasp radial engines for the airframes produced, but they did not bring results soon enough. During the evacuation of the P.Z.L. Warsaw establishment on 5 September, Jerzy Widawski, factory test pilot, attempted to fly the P.50/I prototype to Lwów, but the machine was brought down by a Polish anti-aircraft battery by mistake. Earlier, on 2-3 September, five pre-production P.50 airframes in various advanced stages of assembly, including the first, almost complete, airframe, were transferred from the W.P.1 plant to a motorcar factory in Czerniakowska Street. In 1940 these airframes were taken by the Germans to an unknown destination, presumably to be scrapped.
To ease a disastrous equipment situation, which with the cancellation of the Jastrząb left squadrons with no hope of early replacement for their obsolete and weary P.ll fighters, a rejuvenated version of the P.ll, named Kobuz, was ordered into quantity production as a 'stop-gap' measure. The Kobuz fighters were to be powered by the 840 hp Mercury VIII radials originally produced for the Jastrząb A, the engines having become available in substantial numbers since the winter of 1938-39. Also ordered from France for delivery during 1940 were 160 Morane-Saulnier M.SA06 interceptors, and attempts had been made to obtain British fighters, but only a single Spitfire and a few Hurricanes were promised to Poland in 1939.
Even if the Mercury-powered Jastrząb was not an outstanding aircraft and the P.50 design did lack the ingenuity of the revolutionary Pulawski fighters, the abrupt cancellation of its production on the eve of war did not solve anything. On the contrary, it heightened the crisis in the re-equipment situation and threw the entire aircraft industry into a state of chaos, reducing output almost to nothing. What is more, the fighter, with a built-in development potential, had a good prospect of becoming a formidable weapon if it had been given the chance with a more suitable powerplant.
After the war Dipl Ing Wsiewołod Jakimiuk, working in Canada, Great Britain and France, gained international repute as the designer of the de Havilland Canada DHC-1 Chipmunk and DHC-2 Beaver and the Sud-Est S.E.5000 Baroudeur.
Construction: The P.50 Jastrząb single-seat fighter was a low-wing cantilever monoplane of all-metal construction.
The wing was built in three parts, a centre section carrying the undercarriage units, and two elliptical outer sections with detachable wingtips. The structure comprised a central box built up of light spars, the flanges of the front and rear walls being joined in the fore-and-aft plane by a stress bearing sandwich skin consisting of an internal layer of corrugated 'Alclad' sheet and a smooth outer 'Alclad' shell. The D-section leading edge and trailing edge with widely-spaced former ribs were attached to the main box.
The outer wing panels were provided with automatic Handley Page slots on the leading edge. Split flaps were fitted over the entire span inboard of the ailerons.
The fuselage was an oval-section 'Alclad' monocoque structure. The pilot's cockpit, with a sliding canopy, was provided with full oxygen installation, all-weather equipment, R/T, and ventilation and heating systems.
The tail unit, a cantilever structure covered with smooth 'A1clad' skin, was of similar construction to that of the wing.
The undercarriage, of the divided type, consisted of two inwardly retracting oleo-legs with low-pressure Dowty wheels and a fully retractable tailwheel.
Standard armament of the Jastrząb A comprised four wing-mounted 7,7 mm KM Wz 36 machine-guns, with provision for the internal stowage of fragmentation bombs in place of two of the guns. The later more powerful model was to be armed with. two indigenous 20 mm Wz 38 cannon in the wing roots, supplementing the four wing guns, and could carry a 300 kg (661Ib) bomb under the fuselage.
The 810-840 hp P.Z.L. Mercury VIII nine-cylinder air-cooled radial driving the Hamilton/P.Z.L. three-blade variable-pitch metal airscrew was specified for the Jastrząb A, but any other radial engine of up to 1,200 hp could be installed in the airframe. The Jastrząb II was to be equipped with the 1,200-1,400 hp P.Z.L. Waran air-cooled radial engine, or, alternatively, with other radials of up to 1,600 hp, such as the Bristol/P.Z.L. Hercules or Gnome-Rhone 14N50/51 series. The fuel tanks were housed in the wings.
===================================
NB The only photographs known to exist of the prototype do not show the entire airframe and appear to have been taken during Ciano's visit in February 1939. It looks to me that these photographs are the basis for the prototype being 'bare-metal'. The prototype was not fully completed and ready for flight testing until February 1939 and it may be the case that it was still unpainted at this time. I doubt very much that it remained in this state for much longer. In the late 1930's all prototypes of Polish military aircraft were painted in the standard military scheme of Khaki and Light Blue with chessboards in the usual positions. Sometimes the rudder(s) were painted white. Some aircraft exhibited at the Paris Salon were painted with special high gloss paint and given civil registrations. I believe that once the P.50 prototype was ready for flight is was soon painted in accordance with normal PZL practice.
A few years ago some photographs, looking as though they were taken by German 'tourists' of the incomplete airframes in Czerniakowska Street were sold on Ebay. Soon afterwards another set of photographs turned up. I was given an explanation of where they originated but I lost all my email a few month ago. As best as I can remember they were in a museum exhibition in Warsaw (I think) and taken by a young fellow in the winter of 1939. He may have been an engineering student or interested in aircraft design. I am not sure. Later he joined the Polish resistance and at some point showed the photographs to Cynk. Strangely I have never seen any mention by Cynk that he had seen these photographs. There have been decades of arguments over the exact appearance of the P.50 and these photographs have finally given some answers.
On 22 March, 1939, Gen Ludomil Rayski was relieved of his duties as the C-in-C Lotnictwo Wojskowe at his own request, and Gen Józef Zając gained a great measure of control over Air Force affairs. Prejudiced against radial-powered interceptors and disappointed by the Jastrząb's early trials, which in his view had proved the machine totally unsatisfactory on the counts of speed and manoeuvrability, Zając decided to cancel the whole P.50 production programme. The newly established P.Z.L. W.P.2 plant at Mielec, which was to become the main Jastrząb production centre by the spring of 1940, immediately stopped preparations for the manufacture of the aircraft, but the W.P.1 at Okęcie, which had already laid down 30 airframes of the initial production batch, was allowed to resume work on them in the summer, when the P.50jI began to show signs of improvement. As the French armament loan opened up the possibility of large purchases of French engines, the first pre-production airframe was to be fitted with the 870 hp Gnome-Rhone 14Kirs fourteen-cylinder double-row radial to serve as a development machine for the proposed P.50B Jastrząb B variant, the aircraft being almost ready in September 1939. Moves were also made to obtain either 1,100 hp Gnome-Rhone 14K or 1,000 hp Pratt Whitney Twin Wasp radial engines for the airframes produced, but they did not bring results soon enough. During the evacuation of the P.Z.L. Warsaw establishment on 5 September, Jerzy Widawski, factory test pilot, attempted to fly the P.50/I prototype to Lwów, but the machine was brought down by a Polish anti-aircraft battery by mistake. Earlier, on 2-3 September, five pre-production P.50 airframes in various advanced stages of assembly, including the first, almost complete, airframe, were transferred from the W.P.1 plant to a motorcar factory in Czerniakowska Street. In 1940 these airframes were taken by the Germans to an unknown destination, presumably to be scrapped.
To ease a disastrous equipment situation, which with the cancellation of the Jastrząb left squadrons with no hope of early replacement for their obsolete and weary P.ll fighters, a rejuvenated version of the P.ll, named Kobuz, was ordered into quantity production as a 'stop-gap' measure. The Kobuz fighters were to be powered by the 840 hp Mercury VIII radials originally produced for the Jastrząb A, the engines having become available in substantial numbers since the winter of 1938-39. Also ordered from France for delivery during 1940 were 160 Morane-Saulnier M.SA06 interceptors, and attempts had been made to obtain British fighters, but only a single Spitfire and a few Hurricanes were promised to Poland in 1939.
Even if the Mercury-powered Jastrząb was not an outstanding aircraft and the P.50 design did lack the ingenuity of the revolutionary Pulawski fighters, the abrupt cancellation of its production on the eve of war did not solve anything. On the contrary, it heightened the crisis in the re-equipment situation and threw the entire aircraft industry into a state of chaos, reducing output almost to nothing. What is more, the fighter, with a built-in development potential, had a good prospect of becoming a formidable weapon if it had been given the chance with a more suitable powerplant.
After the war Dipl Ing Wsiewołod Jakimiuk, working in Canada, Great Britain and France, gained international repute as the designer of the de Havilland Canada DHC-1 Chipmunk and DHC-2 Beaver and the Sud-Est S.E.5000 Baroudeur.
Construction: The P.50 Jastrząb single-seat fighter was a low-wing cantilever monoplane of all-metal construction.
The wing was built in three parts, a centre section carrying the undercarriage units, and two elliptical outer sections with detachable wingtips. The structure comprised a central box built up of light spars, the flanges of the front and rear walls being joined in the fore-and-aft plane by a stress bearing sandwich skin consisting of an internal layer of corrugated 'Alclad' sheet and a smooth outer 'Alclad' shell. The D-section leading edge and trailing edge with widely-spaced former ribs were attached to the main box.
The outer wing panels were provided with automatic Handley Page slots on the leading edge. Split flaps were fitted over the entire span inboard of the ailerons.
The fuselage was an oval-section 'Alclad' monocoque structure. The pilot's cockpit, with a sliding canopy, was provided with full oxygen installation, all-weather equipment, R/T, and ventilation and heating systems.
The tail unit, a cantilever structure covered with smooth 'A1clad' skin, was of similar construction to that of the wing.
The undercarriage, of the divided type, consisted of two inwardly retracting oleo-legs with low-pressure Dowty wheels and a fully retractable tailwheel.
Standard armament of the Jastrząb A comprised four wing-mounted 7,7 mm KM Wz 36 machine-guns, with provision for the internal stowage of fragmentation bombs in place of two of the guns. The later more powerful model was to be armed with. two indigenous 20 mm Wz 38 cannon in the wing roots, supplementing the four wing guns, and could carry a 300 kg (661Ib) bomb under the fuselage.
The 810-840 hp P.Z.L. Mercury VIII nine-cylinder air-cooled radial driving the Hamilton/P.Z.L. three-blade variable-pitch metal airscrew was specified for the Jastrząb A, but any other radial engine of up to 1,200 hp could be installed in the airframe. The Jastrząb II was to be equipped with the 1,200-1,400 hp P.Z.L. Waran air-cooled radial engine, or, alternatively, with other radials of up to 1,600 hp, such as the Bristol/P.Z.L. Hercules or Gnome-Rhone 14N50/51 series. The fuel tanks were housed in the wings.
===================================
NB The only photographs known to exist of the prototype do not show the entire airframe and appear to have been taken during Ciano's visit in February 1939. It looks to me that these photographs are the basis for the prototype being 'bare-metal'. The prototype was not fully completed and ready for flight testing until February 1939 and it may be the case that it was still unpainted at this time. I doubt very much that it remained in this state for much longer. In the late 1930's all prototypes of Polish military aircraft were painted in the standard military scheme of Khaki and Light Blue with chessboards in the usual positions. Sometimes the rudder(s) were painted white. Some aircraft exhibited at the Paris Salon were painted with special high gloss paint and given civil registrations. I believe that once the P.50 prototype was ready for flight is was soon painted in accordance with normal PZL practice.
A few years ago some photographs, looking as though they were taken by German 'tourists' of the incomplete airframes in Czerniakowska Street were sold on Ebay. Soon afterwards another set of photographs turned up. I was given an explanation of where they originated but I lost all my email a few month ago. As best as I can remember they were in a museum exhibition in Warsaw (I think) and taken by a young fellow in the winter of 1939. He may have been an engineering student or interested in aircraft design. I am not sure. Later he joined the Polish resistance and at some point showed the photographs to Cynk. Strangely I have never seen any mention by Cynk that he had seen these photographs. There have been decades of arguments over the exact appearance of the P.50 and these photographs have finally given some answers.
