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{|{{Infobox Aircraft Begin
{|{{Infobox aircraft begin
|name = PZL.50 Jastrząb
| name = PZL.50 Jastrząb
|image = File:PZL-50 Jastrzab.jpg
| image = PZL-50 Jastrzab.jpg
|caption =
| caption =
}}{{Infobox Aircraft Type
}}{{Infobox aircraft type
|type = [[Fighter aircraft]]
| type = [[Fighter aircraft]]
|manufacturer =[[PZL|Państwowe Zakłady Lotnicze]]
| manufacturer = [[Państwowe Zakłady Lotnicze]]
|national origin =Poland
| national origin = Poland
|designer =
| designer =
|first flight = February [[1939 in aviation|1939]]
| first flight = February 1939
|introduced =
| introduced =
|retired =
| retired =
|status = Prototype
| status = Never entered service
|primary user = [[Polish Air Force]]
| primary user = [[Polish Air Force]]
|produced = 1939
| produced = 1939
|number built = 1 (+6 incomplete)
| number built = 2 prototypes (+5 incomplete serial aircraft)
|unit cost =
| unit cost =
|variants with their own articles = [[PZL.53 Jastrząb II]]<br/>[[PZL.56 Kania]]
| variants with their own articles = [[PZL.53 Jastrząb II]]<br/>[[PZL.56 Kania]]
}}
}}
|}
|}
The '''PZL.50 Jastrząb''' (''Hawk'') was a [[Poland|Polish]] pre-war [[fighter aircraft]] designed by [[Wsiewołod Jakimiuk]] of the [[Państwowe Zakłady Lotnicze|PZL]] works. The single-seat low-wing monoplane was to serve as a multi-purpose fighter and escort to replace all fighters used previously by the [[Polish Air Force]]. Designed after 1936, its prototype was first flown in February 1939. A further two prototypes were almost ready by the time of the [[Invasion of Poland (1939)|Invasion of Poland]], but the fighter did not manage to enter mass production before the war.
'''PZL.50 Jastrząb''' (''Hawk'') was a Polish late 1930s [[fighter aircraft]] designed by [[Wsiewołod Jakimiuk]] at [[Państwowe Zakłady Lotnicze]]. The single-seat low-wing monoplane was to serve as a multi-purpose fighter and escort to replace all other fighters in the [[Polish Air Force|Polish Military Aviation]]. Designed after 1936, its prototype first flew in February 1939. By September, the first production aircraft were nearing completion, but further development was interrupted by the [[Invasion of Poland|Nazi-Soviet Invasion of Poland]].


==Design and development==
==Design and development==
In early 1930s the Polish Air Force was equipped with the modern [[PZL P.11]] all-metal high-wing monoplanes, the latest of a family of fighter aircraft designed by [[Zygmunt Puławski]]. However, by the end of decade they became obsolete, as new fighter and bomber aircraft with higher performance started to appear. There was no development carried out on other fighters, apart from [[PZL P.24]] export variants of Puławski's P.11 design. By the mid-1930s, the Polish Air Force Command led by Gen. [[Ludomił Rayski]] expected, that a basic Polish general purpose fighter and light bomber would be a twin-engine [[heavy fighter]]-bomber [[PZL.38 Wilk]], supplemented by light, cheap low-wing monoplane [[PZL.39]]/LWS-4.<ref name=cynk1/> While potentially a suitable design, the PZL.38 had problems finding proper engines and the estimated performance of the PZL.39 was too low (maximum speed 400&nbsp;km/h), resulting in both programs being canceled.<ref name=grusz>Gruszczyński, Jerzy. ''Jastrząb nie zdążył...''{{pl icon}}. pp. 46–53.</ref> Future wartime experience showed, that heavy fighters were not well matched against fast single-engine interceptors. It became evident that the Air Force needed a modern [[interceptor aircraft]] to defend the country, and at last, in October 1936, the Armament Committee (KSUS) submitted a demand for such an interceptor.<ref name=cynk1/>
In early 1930s the Polish Air Force was equipped with the then state-of-the-art [[PZL P.11]] all-metal [[gull wing]] monoplanes, the latest of a family of fighter aircraft designed by [[Zygmunt Puławski]]. However, by the end of decade they had become obsolete, as new fighter and bomber aircraft with higher performance started to appear. There was no development carried out on other fighters, apart from [[PZL P.24]], which was an improved export variant of Puławski's P.11 design. By the mid-1930s, the Polish Air Force Command led by Gen. [[Ludomił Rayski]] expected, that a basic Polish general-purpose fighter and light bomber would be a twin-engine [[heavy fighter]]-bomber [[PZL.38 Wilk]], supplemented by a light, cheap low-wing monoplane [[PZL.39]]/LWS-4.<ref name=cynk1/> While potentially a suitable design, the PZL.38 had problems finding proper engines and the estimated performance of the PZL.39 was too low (maximum speed {{convert|400|km/h|abbr=on}}), resulting in both programs being canceled.<ref name=grusz>Gruszczyński, Jerzy. ''Jastrząb nie zdążył...''{{in lang|pl}}. pp. 46–53.</ref> Future wartime experience showed, that heavy fighters were not well matched against fast single-engine interceptors. It became evident that the Air Force needed a modern [[interceptor aircraft]] to defend the country, and at last, in October 1936, the Armament Committee (KSUS) submitted a demand for such an interceptor.<ref name=cynk1/>


In late 1936, Rayski ordered the [[PZL]] (National Aviation Works)'s Chief Designer Wsiewołod Jakimiuk, a lead designer of the P.11c, to abandon work on the [[PZL.44 Wicher]] passenger airliner, and design and start work on a modern single-engine fighter with a retractable landing gear and a speed of some 500&nbsp;km/h. At the same time, Rayski selected the British 840&nbsp;hp [[Bristol Mercury]] VIII radial engine as the project's powerplant. PZL had already manufactured Mercury V engines and would be able to retool to build the later version, as a Polish-produced engine was one of primary considerations in the design.<ref name="Cynk p. 386"/> This choice however restricted performance of the future fighter, and, according to historians, the whole program started at least two years too late.<ref name=cynk2>Cynk, Jerzy B. "PZL.50 Jastrząb w prawdziwej postaci ('The PZL.50 Jastrząb in an authentic shape')"{{pl icon}}. ''[[Skrzydlata Polska]]'', nr. 6/2005, p. 59.</ref>
In late 1936, Rayski ordered the [[Państwowe Zakłady Lotnicze|PZL]]'s Chief Designer Wsiewołod Jakimiuk, a lead designer of the P.11c, to abandon work on the [[PZL.44 Wicher]] passenger airliner, and to start work on a modern single-engine fighter with retractable landing gear and a speed of some {{convert|500|km/h|abbr=on}}. At the same time, Rayski selected the British [[Bristol Mercury]] VIII (840&nbsp;metric hp/825&nbsp;imperial hp) radial engine as the project's powerplant. PZL had already manufactured Mercury V engines and would be able to retool to build the later version, as a Polish-produced engine was one of primary considerations in the design.<ref name="Cynk p. 386"/> This choice however restricted performance of the future fighter, and, according to historians, the whole program started at least two years too late.<ref name=cynk2>Cynk, Jerzy B. "PZL.50 Jastrząb w prawdziwej postaci ('The PZL.50 Jastrząb in an authentic shape')"{{in lang|pl}}. ''[[Skrzydlata Polska]]'', nr. 6/2005, p. 59.</ref>


The project '''PZL.50''' (or '''PZL P.50''') and named Jastrząb (''[[Hawk]]''), started in late 1936.<ref name=cynk1/> The design was accepted by the Air Force Command in 1937 and two prototypes were ordered. In June 1938, 300 Mercury VIII engines were also ordered for the PZL, the first to be delivered in June 1939. The engine for the prototype was imported from Great Britain and fitted in September 1938. The prototype was almost ready by October, but its completion was delayed by the lack of a retractable landing gear, delivered by the British [[Dowty Group|Dowty]] firm.<ref name="Cynk p. 387">Cynk 1962, p. 387.</ref> Due to the delay, the Polish aviation authorities missed the chance of starting flying tests with some temporary fixed landing gear, since the Polish industry had not yet produced suitable retractable gears.<ref name=cynk1/> Avia-manufactured undercarriage units were specified for the production series.<ref name="Cynk p. 387"/>
The project '''PZL.50''' named Jastrząb (''[[Hawk]]''), started in late 1936.<ref name=cynk1/> The design was accepted by the Air Force Command in 1937 and two prototypes were ordered. In June 1938, 300 PZL Merkury VIII engines built under license in PZL WS-1 factory were ordered, with first to be delivered in June 1939. The engine for the prototype was imported from Great Britain and fitted in September 1938. The prototype was almost ready by October, but its completion was delayed by the lack of a retractable landing gear, delivered by the British [[Dowty Group|Dowty]] firm.<ref name="Cynk p. 387">Cynk 1962, p. 387.</ref> Due to the delay, the Polish aviation authorities missed the chance of starting flying tests with some temporary fixed landing gear, since Polish industry had not yet produced suitable retractable gears.<ref name=cynk1/> Avia-manufactured undercarriage units were specified for the production series.<ref name="Cynk p. 387"/>


Finally, the first prototype PZL.50/I was completed and flown in late February 1939 by pilot Jerzy Widawski. Despite being secret, on 27 February it was on static display for the Italian Foreign Minister, Count [[Galeazzo Ciano]].<ref name="Cynk p. 386">Cynk 1962, p. 386.</ref> Tests were carried mainly by [[Bolesław Orliński]] and several other pilots who noted that the prototype, after modifications to the tail, exhibited satisfactory handling and maneuverability characteristics although it not agile enough as an interceptor.<ref name="Cynk pp. 387–388">Cynk 1962, pp. 387–388.</ref> The greatest concern was that even without radio and machine guns, it was only able to achieve 420–430&nbsp;km/h.<ref name="Cynk p. 388">Cynk 1962, p. 388.</ref> The Mercury VIII engine had problems with delivering full power due to an unsuitable carburetor intake and after modifications, the prototype was able to reach 442&nbsp;km/h. Test pilots continued to complain about power output being too low,<ref name=cynk1/> although with a better engine, some observers estimated that a production example would have been able to top 470&nbsp;km/h.<ref name=grusz/>
Finally, the first prototype PZL.50/I was completed and flown in late February 1939 by pilot Jerzy Widawski. Despite being officially classified as a secret, on 27 February it was on static display for the Italian Foreign Minister, Count [[Galeazzo Ciano]].<ref name="Cynk p. 386">Cynk 1962, p. 386.</ref> Tests were carried out mainly by [[Bolesław Orliński]] and several other pilots who noted that the prototype, after modifications to the tail, exhibited satisfactory handling and maneuverability characteristics although it was not agile enough as an interceptor.<ref name="Cynk pp. 387–388">Cynk 1962, pp. 387–388.</ref> The greatest concern was that even without radio and machine guns, it was able to achieve only {{convert|420|to|430|km/h|abbr=on}}.<ref name="Cynk p. 388">Cynk 1962, p. 388.</ref> The Mercury VIII engine had problems with delivering full power due to an unsuitable carburetor intake and, after modifications, the prototype was able to reach {{convert|442|km/h|abbr=on}}. Test pilots continued to complain about power output being too low,<ref name=cynk1/> although with a better engine, some observers estimated that a production example would have been able to top {{convert|470|km/h|abbr=on}}<ref name=grusz/>


It was first planned to order 300 P.50s,<ref>Glass 2008, p. 130.</ref> but in April 1939, the new Air Force Commander Gen. Kalkus and Air Defence Inspector Gen. [[Józef Zając]] estimated that the current PZL.50 design did not meet its specified performance goals and ordered PZL to develop it further, building an improved pattern aircraft with only a limited series of 25-30 aircraft on order, designated the '''P.50A'''.<ref name=cynk1>Cynk, Jerzy B. ''Jastrząb ujawniony''{{pl icon}}, pp. 55–60.</ref><ref name="Greenp121">Green 1961, p. 121.</ref> Production aircraft were to have the wing area increased from 15.8 m² to 19 m².<ref name=grusz/> The total planned order was decreased to 200 and Poland started to look for fighters abroad, ordering 160 [[Morane-Saulnier MS 406]] fighters from [[France]].<ref name="Greenp121"/> As an interim measure, 100 [[PZL P.11]]g ''Kobuz'' fighters were ordered, fitting the P.11c airframe with Mercury VIII engines.<ref name=grusz/>
It was first planned to order 300 PZL.50s,<ref>Glass 2008, p. 130.</ref> but in April 1939, the new Air Force Commander Gen. Kalkus and Air Defence Inspector Gen. [[Józef Zając]] estimated that the current PZL.50 design did not meet its specified performance goals and ordered PZL to develop it further, building an improved pattern aircraft with only a limited series of 25-30 aircraft on order, designated the '''PZL.50A'''.<ref name=cynk1>Cynk, Jerzy B. ''Jastrząb ujawniony''{{in lang|pl}}, pp. 55–60.</ref><ref name="Greenp121">Green 1961, p. 121.</ref> Production aircraft were to have the wing area increased from 15.8 m<sup>2</sup> to 19 m<sup>2</sup>.<ref name=grusz/> The total planned order was decreased to 200 and Poland started to look for fighters abroad, ordering 160 [[Morane-Saulnier MS 406]] fighters from France.<ref name="Greenp121"/> As an interim measure, 100 [[PZL P.11]]g ''Kobuz'' fighters were ordered, fitting the P.11c airframe with Mercury VIII engines.<ref name=grusz/>


The second prototype PZL.50/II was to be equipped with a more powerful 1,200-1,400&nbsp;hp engine, but it eventually had been completed without an engine. Only in 1939, was the PZL.50/II reworked with a 1,100&nbsp;hp [[Gnome-Rhône 14N|Gnome-Rhône 14N21]] for an export variant '''P.50B''' (estimated maximum speed 560&nbsp;km/h<ref name=cynk1/> / 348&nbsp;mph) or 1,150&nbsp;hp [[Bristol Taurus]] III or IV for the Polish Air Force (estimated speed 530–560&nbsp;km/h). The Gnome-Rhone engine was only delivered in August 1939, while the newest British Taurus was scheduled to be delivered in October or November, but final deliveries were prevented by war, nonetheless Taurus development had proved to be troublesome.<ref name=cynk1/> Other possible engine alternatives were the Polish PZL Waran engine, which was to be ready in spring 1940, the 1,000&nbsp;hp [[Pratt & Whitney R-1830|Pratt & Whitney Twin Wasp]] or 1,375&nbsp;hp [[Bristol Hercules]].<ref name="Greenp121"/> As early as 1938, Jakimiuk proposed a variant with the 1,100&nbsp;hp Hispano-Suiza 12Y inline engine, designated PZL.56 Kania, but it was not accepted.<ref name="Cynk p. 388"/>
The second prototype PZL.50/II was to be equipped with a more powerful 1,200-1,400&nbsp;hp engine, but never was. Only in 1939, was the PZL.50/II reworked with a 1,100&nbsp;hp [[Gnome-Rhône 14N|Gnome-Rhône 14N21]] for an export variant '''PZL.50B''' (estimated maximum speed {{convert|560|km/h|abbr=on}}<ref name=cynk1/>) or 1,060&nbsp;hp [[Bristol Taurus]] II or III for the Polish Air Force (estimated speed {{convert|530|to|560|km/h|abbr=on}}). The Gnome-Rhone engine was only delivered in August 1939, while the newest British Taurus was scheduled to be delivered in October or November, but final deliveries were prevented by war. Nonetheless, Taurus development had proved to be troublesome.<ref name=cynk1/> Other possible engine alternatives were the Polish PZL Waran engine, which was to be ready in spring 1940, the 1,000&nbsp;hp [[Pratt & Whitney R-1830|Pratt & Whitney Twin Wasp]] or 1,375&nbsp;hp [[Bristol Hercules]].<ref name="Greenp121"/> As early as 1938, Jakimiuk proposed a variant with the 1,100&nbsp;hp Hispano-Suiza 12Y inline engine, designated PZL.56 Kania, but it was not accepted.<ref name="Cynk p. 388"/>


==Operational history==
==Operational history==
By the end of August 1939, the first unarmed flying prototype PZL.50/I, the second incomplete and engine-less prototype PZL.50/II, an incomplete pattern aircraft PZL.50 and parts of four series PZL.50As were all that were completed. The first prototype had a short fairing behind the canopy, all the others were distinguished by having a cut down rear fuselage to accommodate an "all-round vision hood".<ref name="Cynk p. 387"/> The production series would have incorporated a different canopy and a ventral fuselage fairing. After the German invasion and outbreak of World War II, on 2–3 September 1939, two incomplete aircraft (pattern PZL.50 and PZL.50/II) were moved from the WP-1 factory in Warsaw to car workshops at Czerniakowska street in Warsaw, where they were captured by the Germans, and possibly scrapped after 1940.<ref name=cynk1/>
By the end of August 1939, the first unarmed flying prototype PZL.50/I, the second incomplete and engine-less prototype PZL.50/II, an incomplete preliminary PZL.50. and parts of four PZL.50As were all that was completed. The first prototype had a short fairing behind the canopy, all the others were distinguished by having a cut down rear fuselage to accommodate an "all-round vision hood".<ref name="Cynk p. 387"/> The production series would have incorporated a different canopy and a ventral fuselage fairing. After the German invasion and outbreak of World War II, on 2–3 September 1939, two incomplete aircraft (pattern PZL.50 and PZL.50/II) were moved from the WP-1 factory in [[Warsaw Chopin Airport|Okęcie]] to Citroën plant at Czerniakowska Street, where they were captured by the Germans, and possibly scrapped after 1940.<ref name=cynk1/>


The first prototype was evacuated east when Jan Widawski flew it towards [[Lwów]] on 6 September, but when the fuel ran out, it crashed during a forced landing near [[Rawa Ruska]].<ref name=cynk1/>
The first prototype was flown east by Jan Widawski towards [[Lwów]] on 6 September, but crash landed near [[Rawa Ruska]] upon running out of fuel.<ref name=cynk1/>


Because of the secrecy surrounding the aircraft, for over 65 years its appearance was only partly known based on four photographs of fragments of the first prototype, made during a presentation to Ciano, two of which are shown in the book, ''Polish Aircraft 1893-1939'' by Cynk, which also contains representative drawings of the aircraft.<ref>Cynk 1971, pp. 259–265.</ref> Only in 2005 were a couple of photographs discovered that showed two incomplete aircraft at Czerniakowska street.<ref name=cynk1/> The photographs made by German soldiers and a Polish amateur photographer, made it possible to authentically reconstruct the PZL.50's design features.<ref name=cynk1/>
Because of the secrecy surrounding the aircraft, for over 65 years its existence was only partly known based on four photographs of fragments of the first prototype, made during a presentation to Ciano, two of which are shown in the book, ''Polish Aircraft 1893-1939'' by [[Jerzy Cynk]], which also contains representative drawings of the aircraft.<ref>Cynk 1971, pp. 259–265.</ref> Only in 2005 were a couple of photographs discovered that showed two incomplete aircraft at Czerniakowska street.<ref name=cynk1/> The photographs made by German soldiers and a Polish amateur photographer, made it possible to authentically reconstruct the PZL.50's design features.<ref name=cynk1/>

==Popular culture==
The PZL.50/I Jastrząb was the original aircraft that [[Blackhawk (DC Comics)|Blackhawk]] flew in Poland during the Nazi invasion of 1939.


==Versions==
==Versions==
Line 48: Line 45:
:First prototype.
:First prototype.
;PZL.50/II
;PZL.50/II
:Second prototype with some fuselage shape changes (long canopy fairing) and with simplified engine cowling.<ref>[http://www.altair.com.pl/files/sp/0605/p50.htm ''PZL.50 Jastrząb w prawdziwej postaci'']</ref>
:Second prototype with some fuselage shape changes (long canopy fairing) and with simplified engine cowling.<ref>[http://www.altair.com.pl/files/sp/0605/p50.htm ''PZL.50 Jastrząb w prawdziwej postaci''] {{webarchive|url=https://web.archive.org/web/20070204042932/http://www.altair.com.pl/files/sp/0605/p50.htm |date=2007-02-04 }}</ref>
;PZL.50A
;PZL.50A
:Planned first production variant based on second prototype<ref>Glass 2008, p. 131.</ref> powered by [[Bristol Mercury|Bristol Mercury VIII]] engine (840 hp) and armed with 4 x 7.9 mm machine guns and 100 kg of bombs.
:Planned first production variant based on second prototype,<ref>Glass 2008, p. 131.</ref> powered by [[Bristol Mercury|PZL Merkury VIII]] engine (840 hp) and armed with 4 x 7.92 mm [[Karabin maszynowy wz. 36|km wz.36 machine guns]] and 100 kg of bombs.
;PZL.50B
;PZL.50B
:Planned second production batch powered by [[Bristol Taurus|Bristol Taurus III]] engine (1,145 hp) and armed with 4 x 7.9 mm machine guns, 2 x 20 mm cannon and 300 kg of bombs.
:Planned second production series powered by [[Bristol Taurus|Bristol Taurus II]] (1,060 hp) or [[Gnome-Rhône 14N|Gnome-Rhône 14N21]] engine (1,100 hp) and armed with 4 x 7.92 mm [[Karabin maszynowy wz. 36|km wz.36 machine guns]], 2 x 20 mm [[Nkm wz.38 FK|nkm FK wz.38D cannons]] and 300 kg of bombs.


==Operators (planned)==
==Operators (planned)==
Line 59: Line 56:


==Specifications (PZL.50/I)==
==Specifications (PZL.50/I)==
{{Aircraft specs
{{aircraft specifications
|plane or copter?=plane
|jet or prop?=prop
|ref=<ref>Glass 2008, p. 133.</ref>
|ref=<ref>Glass 2008, p. 133.</ref>
|prime units?=met
|crew=1
<!--
|capacity=
General characteristics
|length main=8.0 m
-->
|length alt=26 ft 3 in
|crew=1
|span main=9.7 m
|length m=8
|span alt=31 ft 10 in
|length note=
|height main=2.7 m
|span m=9.7
|height alt= 8 ft 10 in
|span note=
|area main=15.8 m²
|height m=2.7
|area alt=209 ft²
|height note=
|empty weight main=1,900 kg
|wing area sqm=15.8
|empty weight alt=4,180 lb
|wing area note=
|loaded weight main=2,400 kg
|aspect ratio=<!-- sailplanes -->
|loaded weight alt=5,280 lb
|airfoil=
|engine (prop)= [[Bristol Mercury|Bristol Mercury VIII]]
|empty weight kg=1900
|type of prop=radial engine
|empty weight note=
|number of props=1
|gross weight kg=2400
|power main=840 hp
|gross weight note=
|power alt=627 kW
|max speed main=430 km/h
|max takeoff weight kg=
|max takeoff weight note=
|max speed alt=232 knots, 267 mph
|fuel capacity=
|combat radius main=750 km
|more general=
|combat radius alt= 405 nm, 466 mi
<!--
|ceiling main=7,500 m
Powerplant
|ceiling alt=24,600
-->
|climb rate main= 12 m/s
|eng1 number=1
|climb rate alt= 2,360 ft/min
|eng1 name=[[Bristol Mercury VIII|PZL Merkury VIII]]
|power/mass main=
|eng1 type=9-cylinder air-cooled radial piston engine
|power/mass alt=
|eng1 kw=615
|guns=4 x 7.92 mm PWU wz.36 [[machine gun]]s
|eng1 note=
|bombs=100 kg

|prop blade number=3
|prop name=variable-pitch propeller
|prop dia m=<!-- propeller aircraft -->
|prop dia note=
<!--
Performance
-->
|max speed kmh=430
|max speed note=
|cruise speed kmh=
|cruise speed note=
|stall speed kmh=
|stall speed note=
|never exceed speed kmh=
|never exceed speed note=
|range km=
|range note=
|combat range km=750
|combat range note=
|ferry range km=
|ferry range note=
|endurance=<!-- if range unknown -->
|ceiling m=7500
|ceiling note=
|g limits=<!-- aerobatic -->
|roll rate=<!-- aerobatic -->
|climb rate ms=12
|climb rate note=
|time to altitude=
|wing loading kg/m2=
|wing loading note=
|fuel consumption kg/km=
|power/mass=
|more performance=<!--</br>
*'''Take-off run:''' {{cvt||m|0}}
*'''Take-off run to {{cvt|15|m|0}}:''' {{cvt||m|0}}
*'''Landing run:''' {{cvt||m|0}}
*'''Landing run from {{cvt|15|m|0}}:''' {{cvt||m|0}}-->
<!--
Armament
-->
|guns= 4 x {{cvt|7.92|mm|3}} [[PWU wz.36|km wz.36]] machine guns
|bombs={{cvt|100|kg|0}} of bombs
|avionics=
}}
}}


Line 102: Line 142:
*[[PZL.56 Kania]]
*[[PZL.56 Kania]]
|similar aircraft=
|similar aircraft=
*[[Seversky P-35]]
*[[P-36 Hawk|Curtiss P-36 Hawk]]
*[[Bloch MB.150]]
*[[Bloch MB.150]]
*[[Nakajima Ki-43]]
*[[Brewster F2A Buffalo]]
*[[Curtiss P-36 Hawk]]
*[[Fiat G.50]]
*[[Fokker D.XXI]]
*[[Fokker D.XXI]]
*[[Grumman F4F Wildcat]]
*[[IAR 80]]
*[[Macchi C.200]]
*[[Macchi C.200]]
*[[Fiat G.50]]
*[[MÁVAG Héja]]
*[[Nakajima Ki-43]]
*[[Polikarpov I-180]]
*[[Polikarpov I-180]]
*[[Reggiane Re.2000]]
*[[Seversky P-35]]
*[[Weiss Manfréd WM-23 Ezüst Nyíl]]
}}
}}


Line 117: Line 163:
;Bibliography
;Bibliography
{{refbegin}}
{{refbegin}}
* Cynk, Jerzy B. "Jastrząb ujawniony" ('The Jastrząb revealed') {{pl icon}}. ''[[Skrzydlata Polska]]'', nr. 11/2005, pp.&nbsp;55–60.
* Cynk, Jerzy B. "Jastrząb ujawniony" ('The Jastrząb revealed') {{in lang|pl}}. ''[[Skrzydlata Polska]]'', nr. 11/2005, pp.&nbsp;55–60.
* Cynk, Jerzy B. ''Polish Aircraft 1893-1939''. London, UK: Putnam & Company, 1971. ISBN 0-370-00085-4.
* Cynk, Jerzy B. ''Polish Aircraft 1893-1939''. London, UK: Putnam & Company, 1971. {{ISBN|0-370-00085-4}}.
* Cynk, Jerzy B. "P.Z.L. P.50 Jastrząb (They didn't quite... No. 16)." ''Air Pictorial'', Volume 24, No. 12, December 1962.
* Cynk, Jerzy B. "P.Z.L. P.50 Jastrząb (They didn't quite... No. 16)." ''Air Pictorial'', Volume 24, No. 12, December 1962.
* Green, William. ''Warplanes of the Second World War, Volume Three: Fighters''. London: Macdonald & Co.(Publishers) Ltd., 1961. ISBN 0-356-01447-9.
* Green, William. ''Warplanes of the Second World War, Volume Three: Fighters''. London: Macdonald & Co.(Publishers) Ltd., 1961. {{ISBN|0-356-01447-9}}.
* Glass, Andrzej. ''Polskie Konstrukcje Lotnicze Vol.3'' (In Polish). Sandomierz, Poland: Wydawnictwo Stratus, 2008.
* Glass, Andrzej. ''Polskie Konstrukcje Lotnicze Vol.3'' (In Polish). Sandomierz, Poland: Wydawnictwo Stratus, 2008.
* Gruszczyński, Jerzy. "Jastrząb nie zdążył..." ('The Jastrząb hasn't made it...') {{pl icon}}. ''Lotnictwo'', nr. 12/2005, pp.&nbsp;46–53.
* Gruszczyński, Jerzy. "Jastrząb nie zdążył..." ('The Jastrząb hasn't made it...') {{in lang|pl}}. ''Lotnictwo'', nr. 12/2005, pp.&nbsp;46–53.
{{refend}}
{{refend}}


==External links==
==External links==
{{commons category|PZL.50 Jastrząb}}
* [http://www.altair.com.pl/files/sp/0605/p50.htm ''PZL.50 Jastrząb w prawdziwej postaci'' - article written by Jerzy B. Cynk and published in [[Skrzydlata Polska]] aviation monthly]
* [http://www.republika.pl/awiacja/pzl2.htm#PZL.50 Samoloty PZL do 1939 roku]
* [http://awiacja.republika.pl/pzl-50%20rysunki.htm Drawings of various versions of the PZL.50]
*[http://www.airwar.ru/enc/fww2/pzl50.html Photos and drawing of PZL.50A and 3-d drawing of the PZL.50/I at Ugolok neba]
*[http://www.airwar.ru/enc/fww2/pzl50.html Photos and drawing of PZL.50A and 3-d drawing of the PZL.50/I at Ugolok neba]


{{PZL aircraft}}
{{PZL aircraft}}
{{aviation lists}}


{{DEFAULTSORT:PZL.50 Jastrzab}}
{{DEFAULTSORT:PZL.50 Jastrzab}}
[[Category:Polish fighter aircraft 1930–1939]]
[[Category:1930s Polish fighter aircraft]]
[[Category:World War II Polish fighter aircraft]]
[[Category:World War II Polish fighter aircraft]]
[[Category:PZL aircraft]]
[[Category:Single-engined tractor aircraft]]
[[Category:Low-wing aircraft]]
[[Category:Aircraft first flown in 1939]]

Revision as of 20:27, 31 March 2024

PZL.50 Jastrząb
Role Fighter aircraft
National origin Poland
Manufacturer Państwowe Zakłady Lotnicze
First flight February 1939
Status Never entered service
Primary user Polish Air Force
Produced 1939
Number built 2 prototypes (+5 incomplete serial aircraft)
Variants PZL.53 Jastrząb II
PZL.56 Kania

PZL.50 Jastrząb (Hawk) was a Polish late 1930s fighter aircraft designed by Wsiewołod Jakimiuk at Państwowe Zakłady Lotnicze. The single-seat low-wing monoplane was to serve as a multi-purpose fighter and escort to replace all other fighters in the Polish Military Aviation. Designed after 1936, its prototype first flew in February 1939. By September, the first production aircraft were nearing completion, but further development was interrupted by the Nazi-Soviet Invasion of Poland.

Design and development

In early 1930s the Polish Air Force was equipped with the then state-of-the-art PZL P.11 all-metal gull wing monoplanes, the latest of a family of fighter aircraft designed by Zygmunt Puławski. However, by the end of decade they had become obsolete, as new fighter and bomber aircraft with higher performance started to appear. There was no development carried out on other fighters, apart from PZL P.24, which was an improved export variant of Puławski's P.11 design. By the mid-1930s, the Polish Air Force Command led by Gen. Ludomił Rayski expected, that a basic Polish general-purpose fighter and light bomber would be a twin-engine heavy fighter-bomber PZL.38 Wilk, supplemented by a light, cheap low-wing monoplane PZL.39/LWS-4.[1] While potentially a suitable design, the PZL.38 had problems finding proper engines and the estimated performance of the PZL.39 was too low (maximum speed 400 km/h (250 mph)), resulting in both programs being canceled.[2] Future wartime experience showed, that heavy fighters were not well matched against fast single-engine interceptors. It became evident that the Air Force needed a modern interceptor aircraft to defend the country, and at last, in October 1936, the Armament Committee (KSUS) submitted a demand for such an interceptor.[1]

In late 1936, Rayski ordered the PZL's Chief Designer Wsiewołod Jakimiuk, a lead designer of the P.11c, to abandon work on the PZL.44 Wicher passenger airliner, and to start work on a modern single-engine fighter with retractable landing gear and a speed of some 500 km/h (310 mph). At the same time, Rayski selected the British Bristol Mercury VIII (840 metric hp/825 imperial hp) radial engine as the project's powerplant. PZL had already manufactured Mercury V engines and would be able to retool to build the later version, as a Polish-produced engine was one of primary considerations in the design.[3] This choice however restricted performance of the future fighter, and, according to historians, the whole program started at least two years too late.[4]

The project PZL.50 named Jastrząb (Hawk), started in late 1936.[1] The design was accepted by the Air Force Command in 1937 and two prototypes were ordered. In June 1938, 300 PZL Merkury VIII engines built under license in PZL WS-1 factory were ordered, with first to be delivered in June 1939. The engine for the prototype was imported from Great Britain and fitted in September 1938. The prototype was almost ready by October, but its completion was delayed by the lack of a retractable landing gear, delivered by the British Dowty firm.[5] Due to the delay, the Polish aviation authorities missed the chance of starting flying tests with some temporary fixed landing gear, since Polish industry had not yet produced suitable retractable gears.[1] Avia-manufactured undercarriage units were specified for the production series.[5]

Finally, the first prototype PZL.50/I was completed and flown in late February 1939 by pilot Jerzy Widawski. Despite being officially classified as a secret, on 27 February it was on static display for the Italian Foreign Minister, Count Galeazzo Ciano.[3] Tests were carried out mainly by Bolesław Orliński and several other pilots who noted that the prototype, after modifications to the tail, exhibited satisfactory handling and maneuverability characteristics although it was not agile enough as an interceptor.[6] The greatest concern was that even without radio and machine guns, it was able to achieve only 420 to 430 km/h (260 to 270 mph).[7] The Mercury VIII engine had problems with delivering full power due to an unsuitable carburetor intake and, after modifications, the prototype was able to reach 442 km/h (275 mph). Test pilots continued to complain about power output being too low,[1] although with a better engine, some observers estimated that a production example would have been able to top 470 km/h (290 mph)[2]

It was first planned to order 300 PZL.50s,[8] but in April 1939, the new Air Force Commander Gen. Kalkus and Air Defence Inspector Gen. Józef Zając estimated that the current PZL.50 design did not meet its specified performance goals and ordered PZL to develop it further, building an improved pattern aircraft with only a limited series of 25-30 aircraft on order, designated the PZL.50A.[1][9] Production aircraft were to have the wing area increased from 15.8 m2 to 19 m2.[2] The total planned order was decreased to 200 and Poland started to look for fighters abroad, ordering 160 Morane-Saulnier MS 406 fighters from France.[9] As an interim measure, 100 PZL P.11g Kobuz fighters were ordered, fitting the P.11c airframe with Mercury VIII engines.[2]

The second prototype PZL.50/II was to be equipped with a more powerful 1,200-1,400 hp engine, but never was. Only in 1939, was the PZL.50/II reworked with a 1,100 hp Gnome-Rhône 14N21 for an export variant PZL.50B (estimated maximum speed 560 km/h (350 mph)[1]) or 1,060 hp Bristol Taurus II or III for the Polish Air Force (estimated speed 530 to 560 km/h (330 to 350 mph)). The Gnome-Rhone engine was only delivered in August 1939, while the newest British Taurus was scheduled to be delivered in October or November, but final deliveries were prevented by war. Nonetheless, Taurus development had proved to be troublesome.[1] Other possible engine alternatives were the Polish PZL Waran engine, which was to be ready in spring 1940, the 1,000 hp Pratt & Whitney Twin Wasp or 1,375 hp Bristol Hercules.[9] As early as 1938, Jakimiuk proposed a variant with the 1,100 hp Hispano-Suiza 12Y inline engine, designated PZL.56 Kania, but it was not accepted.[7]

Operational history

By the end of August 1939, the first unarmed flying prototype PZL.50/I, the second incomplete and engine-less prototype PZL.50/II, an incomplete preliminary PZL.50. and parts of four PZL.50As were all that was completed. The first prototype had a short fairing behind the canopy, all the others were distinguished by having a cut down rear fuselage to accommodate an "all-round vision hood".[5] The production series would have incorporated a different canopy and a ventral fuselage fairing. After the German invasion and outbreak of World War II, on 2–3 September 1939, two incomplete aircraft (pattern PZL.50 and PZL.50/II) were moved from the WP-1 factory in Okęcie to Citroën plant at Czerniakowska Street, where they were captured by the Germans, and possibly scrapped after 1940.[1]

The first prototype was flown east by Jan Widawski towards Lwów on 6 September, but crash landed near Rawa Ruska upon running out of fuel.[1]

Because of the secrecy surrounding the aircraft, for over 65 years its existence was only partly known based on four photographs of fragments of the first prototype, made during a presentation to Ciano, two of which are shown in the book, Polish Aircraft 1893-1939 by Jerzy Cynk, which also contains representative drawings of the aircraft.[10] Only in 2005 were a couple of photographs discovered that showed two incomplete aircraft at Czerniakowska street.[1] The photographs made by German soldiers and a Polish amateur photographer, made it possible to authentically reconstruct the PZL.50's design features.[1]

Versions

PZL.50/I
First prototype.
PZL.50/II
Second prototype with some fuselage shape changes (long canopy fairing) and with simplified engine cowling.[11]
PZL.50A
Planned first production variant based on second prototype,[12] powered by PZL Merkury VIII engine (840 hp) and armed with 4 x 7.92 mm km wz.36 machine guns and 100 kg of bombs.
PZL.50B
Planned second production series powered by Bristol Taurus II (1,060 hp) or Gnome-Rhône 14N21 engine (1,100 hp) and armed with 4 x 7.92 mm km wz.36 machine guns, 2 x 20 mm nkm FK wz.38D cannons and 300 kg of bombs.

Operators (planned)

 Poland

Specifications (PZL.50/I)

Data from [13]

General characteristics

  • Crew: 1
  • Length: 8 m (26 ft 3 in)
  • Wingspan: 9.7 m (31 ft 10 in)
  • Height: 2.7 m (8 ft 10 in)
  • Wing area: 15.8 m2 (170 sq ft)
  • Empty weight: 1,900 kg (4,189 lb)
  • Gross weight: 2,400 kg (5,291 lb)
  • Powerplant: 1 × PZL Merkury VIII 9-cylinder air-cooled radial piston engine, 615 kW (825 hp)
  • Propellers: 3-bladed variable-pitch propeller

Performance

  • Maximum speed: 430 km/h (270 mph, 230 kn)
  • Combat range: 750 km (470 mi, 400 nmi)
  • Service ceiling: 7,500 m (24,600 ft)
  • Rate of climb: 12 m/s (2,400 ft/min)

Armament

  • Guns: 4 x 7.92 mm (0.312 in) km wz.36 machine guns
  • Bombs: 100 kg (220 lb) of bombs

See also

Related development

Aircraft of comparable role, configuration, and era

References

Notes
  1. ^ a b c d e f g h i j k l Cynk, Jerzy B. Jastrząb ujawniony(in Polish), pp. 55–60.
  2. ^ a b c d Gruszczyński, Jerzy. Jastrząb nie zdążył...(in Polish). pp. 46–53.
  3. ^ a b Cynk 1962, p. 386.
  4. ^ Cynk, Jerzy B. "PZL.50 Jastrząb w prawdziwej postaci ('The PZL.50 Jastrząb in an authentic shape')"(in Polish). Skrzydlata Polska, nr. 6/2005, p. 59.
  5. ^ a b c Cynk 1962, p. 387.
  6. ^ Cynk 1962, pp. 387–388.
  7. ^ a b Cynk 1962, p. 388.
  8. ^ Glass 2008, p. 130.
  9. ^ a b c Green 1961, p. 121.
  10. ^ Cynk 1971, pp. 259–265.
  11. ^ PZL.50 Jastrząb w prawdziwej postaci Archived 2007-02-04 at the Wayback Machine
  12. ^ Glass 2008, p. 131.
  13. ^ Glass 2008, p. 133.
Bibliography
  • Cynk, Jerzy B. "Jastrząb ujawniony" ('The Jastrząb revealed') (in Polish). Skrzydlata Polska, nr. 11/2005, pp. 55–60.
  • Cynk, Jerzy B. Polish Aircraft 1893-1939. London, UK: Putnam & Company, 1971. ISBN 0-370-00085-4.
  • Cynk, Jerzy B. "P.Z.L. P.50 Jastrząb (They didn't quite... No. 16)." Air Pictorial, Volume 24, No. 12, December 1962.
  • Green, William. Warplanes of the Second World War, Volume Three: Fighters. London: Macdonald & Co.(Publishers) Ltd., 1961. ISBN 0-356-01447-9.
  • Glass, Andrzej. Polskie Konstrukcje Lotnicze Vol.3 (In Polish). Sandomierz, Poland: Wydawnictwo Stratus, 2008.
  • Gruszczyński, Jerzy. "Jastrząb nie zdążył..." ('The Jastrząb hasn't made it...') (in Polish). Lotnictwo, nr. 12/2005, pp. 46–53.

External links

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