PZL P.50, Akkura 1/72 scale

[Mitch K]

Not sure this qualifies as a silk purse, but the Akkura kit make a strong case for being a sow's ear. The data information on the P.50 is (at best) incomplete, and as the design was being refined constantly, there isn't a "definitive version" of the aircraft, as such. 

 

The PZL P.50 was the Polish Air Force's response to the knowledge that whilst the P.11 had been the best fighter in the world when it first appeared, that day was long gone and it was woefully dated. The P.50 has all the characteristics of the next generation of fighters: enclosed cockpit, all-metal structure, retractable undercarriage etc. It rather resembles aircraft like the Re. 2000, Seversky P.35, Curtiss P.36 and the like, showing the impact of "convergent evolution" of different designs intended to meet the same need.

 

The P.50 was powered by a Bristol Mercury VIII, as fitted to the Gloster Gladiator and Bristol Blenheim. This apparently left the design underpowered, slow and rather sluggish. I say "apparently" as the same engine was fitted to the Gloster F5/34 and Bristol 146, both of which reported higher performance that the P.50 whilst not seeming to be much more refined. There were plan afoot to fit more powerful engines, including a Bristol Hercules, which would have provided a massive increase in power, albeit at the cost of greatly increasing the wing loading. Events overtook this and no combat versions were built.

 

The WIP is here:

http://www.britmodeller.com/forums/index.php?/topic/235018912-pzl-p50/

 

I replaced the cowling, engine, prop and exhausts, scratchbuilt the undercarriage and cockpit, fitted new navigation and landing lights and completely rescribed the panel lines, but apart from that, this is largely built OOB!

 

(Edit - for some reason, I could't get the pictures to upload. The site seemed VERY unhappy with the "large size" version of the pictures from Flickr, which are normally fine.)

 

 

 

 

 

 

A shot alongside her predecessor:

 

 

And another, with a couple of the more famous contemporary designs, for comparison

 

 

 

[Colin1967]

Lovely build of an interesting aircraft, really like the pics supplied as well, makes an interesting comparison.

[stevehnz]

A really nice job on that &  great addition to any collection. I did look at this kit a while back but after following your WIP, I'll just enjoy yours.

Steve.

[Mitch K]

I've got another one to do!

[stevehnz]

That's a bit keen. I'll happily watch that one too.

Steve.

[GrzeM]

Good job! Only the camouflage colours you've used are not very Polish (at least at that time).

 

If you're serious into P.50, there is a really good resin kit by Ardpol, released quite recently.

Here is one built by Jerzy Ciupek "Hadzi":

 

More on the Polish Forum: http://pwm.org.pl/viewtopic.php?f=13&t=27041

[Mitch K]

25 minutes ago, stevehnz said:

That's a bit keen. I'll happily watch that one too.

Steve.

You get two in the box! The next one will get real "what if" butchery!

[Mitch K]

Just now, GrzeM said:

Good job! Only the camouflage colours you've used are not very Polish (at least at that time).

 

If you're serious into P.50, there is a really good resin kit by Ardpol, released quite recently.

Here is one built by Jerzy Ciupek "Hadzi":

 

More on the Polish Forum: http://pwm.org.pl/viewtopic.php?f=13&t=27041

Nice! As I said the dark colour on mine is "standard" khaki (although I'm aware of there being two variations: this one, and a second, more like RAF Dark Earth). The light colour is a punt at "Light Olive (Jasnooliwkowy)", as described here:

http://www.ipmsstockholm.org/colorcharts/stuff_eng_colorcharts_poland.htm

The contrast looks about right for the PZL P.11 from (I think) 112 or 113 Esk that appears in a series of photos in a two-colour scheme. 

[303sqn]

From Polish Aircraft 1893-1939, Jerzy B Cynk, Putnam, 1971.

 

In the second half of 1936 the original plan to completely replace the P.11 with the twin-engined, two-seat P.39 strike fighter (originally two designations were reserved for the project: P.38 for the high-altitude general purpose attack/escort fighter variant, and P.39 for the low-altitude dive-bomber and strike/interceptor fighter variant.) was abandoned and replaced with the view 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 close defence of specific targets. The fast long range fighter, eventually known as the P.38 Wilk, could chase enemy raiders over the whole country and would be used only in the complimentary capacity.

 

The P.24 was briefly considered for the role, but as it would only offer a marginal improvement over the P.11, the Aviation Command favoured a more progressive design. In the autumn of 1936 Wsiewołod Jakimiuk, head of the PZL fighter team, proposed an advanced low wing monoplane with improved all-round performance and offered great scope for future development. Rather than develop a projection of the P.11/P.24 line with a low cantilever wing (as the Romanians did with the IAR 80/81) Jakimiuk, influenced by American design philosophy, particularly the Seversky monoplanes, created a design easily adapted to take larger engines, which bore some resemblance to the Seversky aircraft. Given the number 50 in the PZL designation sequence it, and Korsak's P.45 study for a lightweight interceptor, became the final contenders for the hunter fighter requirement with the P.50 being given preference for immediate development.

 

Given the name Jastrząb (Hawk) a full interceptor specifiaction was written around the study by the Aviation Command in collaboration with the ITL. Because of a lack time, due to the earlier interest in the P.39 two years had already been lost, it was decided to use a lower powered but well proven engine, the 840 hp Mercury VIII, to power the first production variant, the P.50A. Top speed was estimated to be 500 km/h at 4,300 m and this was considered adequate for target defence purposes. Armament was to be four wing mounted 7.7 mm machine guns. Detailed design and mock-up were approved in the autumn of 1937 and the construction of a static test airframe and two prototypes – the P.50/I designed to take radials up to 1,200 hp and generally corresponding to the P.50A, and the P.50/II stressed for radials up to 1,600 hp and much more in line with Jakimiuk's original intentions – began at the W.P.1 plant.

 

In the meantime the XVIIth Session of the KSUS, sitting in October 1936, approved the four year expansion programme of the Lotnictwo Wojskowe to be completed by 31^th March 1941. This called for 15 squadrons of single seat interceptors with ten aircraft per squadron and a 100% reserve. In view of this and because of the quickly deteriorating equipment situation in the fighter field, the Aviation Command ordered 300 P.50As off the drawing board, paying for the first 100 in advance in 1938. Delivery of the first 50 was expected by September 1939. At the same time the PZL WS1 at Okęcie received production contracts for 450 Mercury VII engines. To speed up the P50 programme the Dowty company was given an order for an inwardly retracting undercarriage for the P50/I prototype while the PZL designed, Avia manufactured gear was being deleoped for the production model. Unfortunately the Dowty undercarriage arrived over four months late. Along with this the Mercury VIII (No M42102), despatched to Poland on 28^th July 1938, could not fly until the following February.

 

Flight trials conducted by the factory's chief test pilot, Maj Bolesław Orliński, were not encouraging. The aircraft proved to be too massive for the Bristol and PZL Mercury VIII. Rate of climb of climb was poor and the top speed in the fully loaded condition was only 442 km/h. The aircraft was unstable in low speed turns and tail flutter developed at the higher end of the speed scale. Modifications were made but during a second set of trials in April Orliński reported further major improvements would be necessary. A puzzelin g aspect of the trial was that none of the engines fitted to the P50/I developed full power. Then in May, a young engineer, examining the prototype, was suddenly struck by the though that the carburettor air intake was too small. He was soon proved right. The intake was taken from an engine of another type and its suitability for the Mercury installation was not examined. In early summer the an enlarged intake was fitted and this together with changes to the tail unit and wing/fuselage fillets resulted in a considerably improved performance and handling characteristics. By the outbreak of war the ITL airworthiness tests had not been entirely completed and Service acceptance trials, conducted by the Experimental Wing attached to the ITL had not begun.

 

The much more potent P.50/II airframe, substantially differing from the P.50/I, had been completed in the spring of 1939 and was waiting for an engine. The machine featured an all-round vision hood and slimmer rear fuselage, provision for additional fuel tanks and a 300 kg bomb under the fuselage for dive-bombing. The pilots 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. Power was to be supplied by the indigenous designed PZL Waran radial rated at 1,200 to 1,400 hp guaranteeing a maximum speed of 560 km/h. Unfortunately development of the Waran was behind schedule and there was little prospect of it being available for installation before the middle of 1940. In the search for a solution to the problem a number of other engines were considered and the 1,375 Bristol Hercules and the 1,400 Gnome-Rhône 14N50 series were selected as suitable alternatives. It seems that the decision to test the P.50/II with the Hercules was taken and in view of the structural differences between the P.50/II and P.50A 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 1938In the second half 1938, with General Zając's critical re-appraisal of the LW's re-equipment prospects and mounting opposition to General Rayski's unreserved faith in the concept of a radial-powered fighter, the possibility of purchasing the manufacturing rights for the powerful Hispano-Ssuiza liquid cooled vee engines began to be explored. Anticipating events, Jakimiuk began initial work on a projection of the basic P.50 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. 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.

 

On 22 March, 1939, General Ludomił Rayski was relieved of his duties as the C-in-C LW at his own request, and General Józef Zając gained a great measure of control over LW affairs. Prejudiced against radial powered interceptors and disappointed by the P.50'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 PZL WP2 plant at Mielec, which was to become the main P.50 production centre by the spring of 1940, immediately stopped preparations for the manufacture of the aircraft, but the WP1 plant 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.50/I began to 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 performance Gnome-Rhône 14Kirs fourteen-cylinder double-row radial to serve as a development machine for the proposed P.50B variant, the aircraft being almost ready in September 1939. Moves were also made to obtain either 1,100 hp Gnome-Rhône 14K or 1,000 hp Pratt & Whitney Twin Wasp radials engines for the airframes produced, but it did not bring results soon enough. During the evacuation of the PZL Warsaw establishment on 5 September, Jerzy Widawski, a 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 WP1 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 the disastrous equipment situation, which with the cancellation of the P.50 left squadrons with no hope of early replacement for their obsolete and weary P.11 fighters, a rejuvenated version of the P.11, 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 P.50A, 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 MS.406 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 P.50was not an outstanding aircraft and the P.50 design did lack the ingenuity of the revolutionary Puławski 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 to almost nothing. What is more, the fighter, with a built in development potential, had the 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 DHC-1 Chipmunk and DHC-2 Beaver and the Sud-Est SE 5000 Baroudeur.

 

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 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 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 Alclad 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 fully retractable tailwheel.

 

Standard armament of the P.50A comprised four wing mounted 7.7 mm KM Wz 36 machine guns, with provision for 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 bomb under the fuselage.

 

The 810-840 hp PZL Mercury VIII nine-cylinder air-cooled radial driving the Hamilton/PZL three blade variable pitch metal airscrew was specified for the P50A, but any other radial engine of up to 1,200 hp could be installed in the airframe. The P50/II was to be equipped with the 1,200-1,400 hp PZL Waran air-cooled radial engine, or, alternatively, with other radials of up to 1,600 hp, such as the Bristol/PZL Hercules or Gnome-Rhône 14N50/51 series. The fuel tanks were housed in the wings.

 

[GrzeM]

On 3.06.2017 at 0:35 AM, Mitch K said:

Nice! As I said the dark colour on mine is "standard" khaki (although I'm aware of there being two variations: this one, and a second, more like RAF Dark Earth). The light colour is a punt at "Light Olive (Jasnooliwkowy)", as described here:

http://www.ipmsstockholm.org/colorcharts/stuff_eng_colorcharts_poland.htm

The contrast looks about right for the PZL P.11 from (I think) 112 or 113 Esk that appears in a series of photos in a two-colour scheme. 

All right, so I suppose that's my badly calibrated monitor shows me quite venomous grass-green instead of the correct olive green hue.

Also the khaki may be perfectly right, but on my monitor it looks very similar to the Dark Green of the Spitfire standing nearby.

 

I'm that smartass today as I'm in the middle of writing an article about "Polish khaki" variants for modelpaint.pl website. It's very complex topic. Recent research (based on the recently found original paint chips of the producer and examination of museum and archeological samples) tend to show the Polish khaki more into olive and brown (in its three described variants) than into greens. But as I wrote - it's very complex...

 

Your model is very good and choice of that two-colour splinter scheme from 1939 "white 3" P.11c is very reasonable for such what-if project. I wonder if we find some samples from that (splinter-painted P.11c) airplane someday. It is possible, as for some time Germans exhibited it as a war trophy in the markeplace of one of the polish towns - between trenches freshly dug in sandy soil. The plane was continuously deconstucted by spectators and I'm sure that at least some parts just felt into sand and are still there, after the trenches have been buried.

[Mitch K]

GrzeM,

 

Thanks for this - I was aware that the subject of "Polish khaki" was not entirely straightforward (that much at least has come across into English), but from what you  say I'm guessing it's more complex even than that. I'm aware of questions around RAF/USAAF colours, and if questions arise in a situation where the records are very largely intact, it gives a strong sense of how challenging it must be to address and reconstruct information on the Polish Air Force.

 

We can but hope some of the unique P.11 survived! Although based on my experience working on the stability of paints, I would say that nearly eighty years buried in anything might make reliably matching the colour back to its original condition a little tricky!

[old thumper]

This is interesting stuff, plus a nice model of course.