Polish AF: preparing for 1939

[kool kitty89]

When licence production of GR 14K was possible in Polish high command there were no interest in high power engine for the fighters. Till 1938 the PZL.38 Wilk was under development with pair of Foka engines - both should produce no less power as one powerful engine (2 x 420HP). Moreover, the Foka engines could be used solely for other types: P.39 lightweight fighter and LWS-3 Mewa reconnaissance aircraft. After the Foka fiasco a new engine was necessary. For the classic pursuit fighter (P.50) the Mercury VIII was chosen, as well GR 14M for other types (PZL.45 Sokół lightweight fighter, LWS-3 Mewa, PZL.48 Lampart two engine destroyer).

Aside from throwing out the light + heavy fighter concepts entirely, it seems like having both the light-weight PZL.39 and 'heavy' PZL.38 had used the existing Mercury VI.S2 engines as alternatives. (some of the engines actually considered for those planes -like the Gypsy twelve- were already about as heavy or heavier than the older Mercury while lower performing and the only advantage being smaller frontal area)

The PZL.39 itself did lead to the later PZL.45 project, and something close to that but using the older 645 hp Mercury engine from the start might have shown up soon enough to make a difference. Either developing a new, light fighter around the Mercury VI.S2 engine or using the PZL.11C (or possibly P.24) fuselage but using a smaller, low wing with fixed landing gear instead as an interim 'light' fighter. (faster but less maneuverable than the P.11) Climb rate would still be a problem with that older engine, though and tended to be a problem for most 'light' fighters in general. Though I guess a small, but thick wing would make for useful lift at low speeds and better take-off, turning ability, and better space for guns.

Continuing to use the old Mercury VI.S2 with the light fighter concept would mean similar forward fuselage structure could be used from the P.11 as well, keeping weight down and simplifying production. (it would limit further development, but that's where the P.50 would come in anyway) If the P.24 fuselage was used, and the new wing was designed with at least a little more power in mind, it shouldn't have been difficult to adapt the Mercury VIII when it was ready. (or for the Romanians to install 14k engines)

OK, but again Pegasus engines was not suitable for a fighters. Mercury VI was not considered any more for the future aircraft due an obsolete construction. On summer 1939 a licence production of Mercury VIII has begun and few dozen engines were produced before the war broke (captured engines Germans sold to Finland). After the summer tests of the P.50 prototype, this aircraft was found underpowered and PZL started looking for another powerplant. All Mercury VIII production was directed to P.11g "emergency fighter program".

Yes yes, but I'm thinking of developments starting back around 1934/35, including interim fighter projects or light fighters and the PZL.38 and 39 projects specifically. Going with the old Mercury VI for the interim wouldn't be that big a step from the planned air cooled V-8 and V-12 engines. Development plans potentially following the pace of the PZL.37 bomber project.

I guess a better idea might have been to design the PZL.37 around Mercury VIII engines instead (more like the Blenheim) with more of a fast-bomber approach with somewhat reduced maximum load and then have a new, powerful engine with good altitude performance useful for a new generation of fighters and bombers.


One final thought on the Gnome Rhone engine topic: did Romania's license for the 14k not allow for them to export engines? With France being unreliable, it seems like importing Romanian manufactured 14ks would be much more attractive.

 

[Timppa]

One thing is true though... believing in the military treaties with the western countries led Poland to the defeat.

True words. Western countries declared war to only one country of the two who invaded Poland.

During the Winter War Churchill spoke:
"We cannot tell what the fate of Finland may be, but no more mournful spectacle could be presented to what is left to civilized mankind than that this splendid Northern race should be at last worn down and reduced to servitude worse than death by the dull brutish force of overwhelming numbers. If the light of freedom which still burns so brightly in the frozen North should be finally quenched, it might well herald a return to the Dark Ages, when every vestige of human progress during two thousand years would be engulfed."

Less than two years from that speech Britain declared war on on Finland and did everything to quench that light. To appease the most tyrannical regime of the twentieth century.

Welcome to the world of "Realpolitik".

 

[Greyman]

... and did everything to quench that light.

Bit of hyperbole, there.

 

[parsifal]

The prime enemy was always Nazi Germany, and by unfortunate circumstance Finland was forced into alliance with that country after the Soviets attacked them again in 1941. Britain showed remarkable consistency in that regard. Any European nation that sided with Germany regardless of the reason was dealt with as an enemy. Not always a declaration of war, but they were made to suffer if they decided to provide significant help to the Germans. This usually took the form of confiscating ships and restricting their seaborne trade, as was the case for the Russians until they too were forced into the Allied camp. Any ship under the Soviet flag was detained and taken in prize.

The declaration of war on Finland was the price that had to be paid and arose primarily because the Finns decided to let German forces into their country as allies. This was totally unacceptable to the British.

Having said that, at the end of the war, it was largely intervention by the British and to a lesser extent the US that saved Finland from Soviet takeover in 1945.

Poland was never so lucky, and it is to our shame that we allowed to happen what happened

 

[Timppa]

it was largely intervention by the British and to a lesser extent the US that saved Finland from Soviet takeover in 1945.

What a baloney.
What made Finland different from Poland, Estonia, Lithuania, Latvia, Romania, Bulgaria,Hungary and Czechoslovakia?
Good will from British ?

 

[Balljoint]

What a baloney.
What made Finland different from Poland, Estonia, Lithuania, Latvia, Romania, Bulgaria,Hungary and Czechoslovakia?
Good will from British ?

Just as Great Britain held its nose and allied with Stalin, Finland allied with Germany as the Soviets were by far the greater threat. But Finland was never fascist. Just the opposite, it maintained true democracy and treated its Jews as it did all its citizens.

After the war Finland was adjudged an Axis entity and paid substantial retribution to the Soviets. But I'm not aware of accusation/charges of war crimes.

 

[Koopernic]

What a baloney.
What made Finland different from Poland, Estonia, Lithuania, Latvia, Romania, Bulgaria,Hungary and Czechoslovakia?
Good will from British ?

Indeed, I have to agree. Finland received as much Goodwill from Germany as Britain, the latter which had some kind of strategy of using Finland as a springboard excuse for cutting of German Iron Ore supplies from Sweden by a Goodwill occupation of Norwegian ports. The Germans also needed Nikel and at least part of Hitlers no retreat order was to preserve that supply as long as possible.

The Molotov Ribbentrop pact specifically guaranteed Estonian independence for instance however it did break up the Baltic into spheres of economic and treaty influence. When the Soviets started regarding 'sphere of influence' as the right to invade and annex alarm bells went of in Berlin (likewise over threats to Romanian oil supplies). The first Soviet attack on Finland was one of these alarm bells.

The long planned "Goodwill" invasion of Norway by Britain known as operation Wilfred (belatedly implemented the day before the German invasion with a preliminary mining operation) lead to a ferocious German response since this would have cut of 80% of Germany's Iron Ore supplies from Sweden (the cause of their loss of WW1). Britain's (Churchill's) invasion of Norway (accurately anticipated by German intelligence) meant that Denmark had to be invaded to protect the supply routes to Norway from the Royal Navy and while you are going to hell in a hand basket you might as well invade Holland which might enjoy goodwill invasion in the future as well. This is the 'cornered animal' response.

Finland of course secured an armistice with the Soviet Union to secure their post war independence, part of that was asking the German troops to leave and then declaring war on their erstwhile allies Germany. Plus there was the grudging respect the Finns earned from the soviets from their powerful resistance.

The problem with diplomatic Goodwill is that it often hides ulterior motives. The Goodwill invasion of Iran by Britain to get at Communist Russia lead to the dethroning of the legitimate and progressive Shah and the current problems in that country.

Finland at the time was ethnically homogenous at that time, although now it is visibly gaining diversity with say quite a lot of Somalis. As far as "Jews' go: they did not figure in Finnish politics as there were, I believe, perhaps 300 living in that country at the time. They were however quite visible in Vienna and Berlin being perhaps 40% 50% of Lawyers, Doctors etc. in those cities.

 

[Koopernic]

The Best Polish engine for 1939 was probably a Daimler Benz DB600 or Jumo 211.

The problems between Poland and Germany were not so insuperable.

Hitler was an Austrian though a pan-German nationalist. As a southerner he had no particular truck with the Poles. He had in fact offered a Polish-German friendship treaty that was in a thinly disguised anti Soviet military treaty. His concern was the economic viability of marooned North Prussia and the German Hanseatic Port of Danzig which was of enormous cultural significant. To secure this he wanted a rail and freeway link 'right of way' to Danzig in return for the anti soviet pact. The treaty foundered on Polish instance on customs inspections (which would have destroyed the viability of the free trade zone). Other tensions included the disenfancshiment of ethnic German land owners in Poland and a continuous level of ongoing low level anti German hate crime (about 2000 to 4000 victims before the war) which Hitler seemed prepared to stomach.

There is evidence that Chamberlains Guarantee of Polish independence was meant as not complete integrity and backing of the Polish position and that chamberlain still wanted negotiation over German Grievances.

Had the Polish Dictator, Beck, played his cards differently Poland might have had a powerful allie against the Soviet Union that could have supplied a lot of world class licence technology with no threat of a German invasion.

Poland was not deindustrialised. When part of the Prussian and then German empire it had industrialised and had manufacturing capacity. In 1919 the Poles had stopped Trotsky's massive Bolshevik Army which would invade Poland and a disarmed Germany.

licence building French designs would not give them a lead.

The HS12 series was slow in developing and no better than the Italian water cooled inlines of around 860hp and MS460 and DW520 used by German training squadrons were universally hated for their viscous unannounced stalls and spins. The French simply had not had the time to debug these things. The Swiss made them work though, after a few years.

 

[kool kitty89]

Welcome to the world of "Realpolitik".

More like false, shortsighted ignorance passed off as some sort of detached pragmatism.

The likes of which I'd hope most of the great turn of the century statesmen would have been ashamed to witness. Bismark in particular, Teddy Roosevelt comes to mind too (both very nationalistic but also very centered on stability and very active international influence) Even Taft with his more legal/economic-centered dollar diplomacy was far more involved and aware of world politics and potential big-picture consequences. (all of them had plenty of selfish, or nationalistic goals that ended up ALSO favoring stability and general world progress due to sensibility -Taft's methods might have been more efficient in the end, but Roosevelt's more active, visible, aggressive approach probably appealed much better to the masses and fit better into typical national politics and culture -appear too 'weak' and you loose influence no matter how right you are)

Honestly, I'd think Churchill was shamed of many of those actions (or lack thereof as well). He was far from perfect, but he at least seems to have seen Stalin for what he was and how real a threat the USSR was bot before and especially at the end of the War. (of course he also saw Hitler for what he was prior to the war) He certainly was very nationalistic as well, but I really can't see him standing by had he been Prime Minister in 1939 ... or 1938 for that matter.

It's a matter of pragmatism or 'realpolitik' philosophy in the proactive interventionist vs falsely practical isolationism (only sensible when you literally have NO resources to be influential) as well as vengeful or reactionary retaliation. Stalin's actions might have been more genuinely of the realpolitik sort, but his end goals were pretty awful, willfully selfish, and in general, harmful to his own people and the world. (I'm trying to stay objective here, but I have a very serious bias against Stalin and Stalinism in deep philosophical, rational, and emotional ways, so I've tried to avoid using emotive speech as much as possible here)

The prime enemy was always Nazi Germany

By 1940, certainly, prior to, or immediately after the invasion of Poland, it would be less obvious. After the Fall of France, Germany gained enough resources to be seriously dangerous and the obvious threat. There likely was too much sympathy for the Soviets pre-war with the spread of communism and the unfortunate tendency to associate the USSR with communist/socialist ideals in general. (rather than seeing it for what it was, and what Stalin stood for)

That's not just a matter of military support, but potentially more aggressive diplomatic negotiations and economic pressures to prevent the invasions in the first place. (and using both the carrot and the stick ... appealing to common ground while never fully trusting German or Soviet leadership)

Of course, that was hardly limited to Britain, and while France was a political mess, there was a good deal more potential common ground and mutual benefit from the likes of (at least some of) the Scandinavian countries, Poland, Romania, Finland, some of the Slavic countries, Denmark, The Netherlands, possibly Belgium, and possibly the disputed Baltic states to form various alliances or particularly favorable trade agreements. (Finland, Romania, and Poland had the most immediate united cause against Russia -same for the Baltic states- and all of those save Finland had looming threats and pressure from Germany as well)

The good thing about Britain was that they were at least economically and politically stable enough to provide good trade resources pre-war and good shipping trade in particular (useful to Poland and other coastal countries). Same was true for the US, though Poland didn't seem to much rely on American trade for military goods. (Finland certainly did to some extent)

The declaration of war on Finland was the price that had to be paid and arose primarily because the Finns decided to let German forces into their country as allies. This was totally unacceptable to the British.

Having said that, at the end of the war, it was largely intervention by the British and to a lesser extent the US that saved Finland from Soviet takeover in 1945.

Poland was never so lucky, and it is to our shame that we allowed to happen what happened

Not just a shame to Poland, but a shame to everyone that the war wasn't quashed early on by diplomatic, economic, and material aid. I suppose I said enough on that above though, and it's really a matter of isolationism vs more proactive interventionism. (NOT just pre-emptive military action, but proactive diplomatic and international dealings in general ... the sort that held together the fragile peace before WWI -in no small part because of Bismark's efforts- and to some extent American interventionism under Theodore Roosevelt and Taft prior to the shift towards Isolationism during Wilson's Administration that deepened in the 1920s and 30s)

So not just isolationism, or even selfishness, but general shortsightedness. (and unwillingness to compromise) Granted, Hitler's ideals themselves fed into this same fault, on top of other ... horrible beliefs and heavy, impulsive reactionism. I don't think Stalin behaved as such, he may have been paranoid, but he seems to have been far more calculating in most of his actions and more aware of all the greater consequences of those actions. (and less driven by superstition or hatred fueled faulty beliefs of certain races/ethnic groups being inherently evil -and faulty understanding of history or the nature of WWI)


Hmm, unless I misread your post and you were describing Finland's actions as Realpolitik as their alliance with Germany was indeed quite obvious the most practical and pragmatic move they could have made, as was their later armistice with Russia and declaration of war on Germany. Finland seemed to be the only country willing to be consistently practical and efficient in both politics and warfare strategy and tactics both prior to and throughout the war. Had More of the smaller countries done so prior to the war ... well, that's exactly what I've been suggesting as far as alliances among the 'smaller' countries. (admittedly, Poland was hardly small, but militaristically its force was much smaller than the likes of Russia, France, or Britain -or Germany after rearmament)

That includes potential alliances with Germany not out of any sort of trust or sympathy, but practical compromise. (the exact context of any sort of 'intentionally dishonest' alliance made by Poland with Germany) I suppose that's also basically cold war style actions and posturing ... having all those alliances and treaties internationally publicized would be important too. (none of the secret treaties that complicated pre-WWI Europe)

Just as Great Britain held its nose and allied with Stalin, Finland allied with Germany as the Soviets were by far the greater threat. But Finland was never fascist. Just the opposite, it maintained true democracy and treated its Jews as it did all its citizens.

After the war Finland was adjudged an Axis entity and paid substantial retribution to the Soviets. But I'm not aware of accusation/charges of war crimes.

To be completely fair to the British, Churchill had been far more wary about continued support to the Soviets and more willing to (potentially) break ... or bend their alliance late in the war when the possibility of conditional surrender (with particularly unfavorable results for the Soviets) was very possible. Or more likely, be ... selective of the sort of aid given to the Soviets in preparation for the immediate post-war threat. Of course, it was Roosevelt who forced the unconditional surrender and also had control of the biggest foreign resources supporting the Soviet warmachine. (tactfully limiting Lend-lease support to the USSR would have very well limited their potential post-war influence and limit portions of the wartime Soviet advance without compromising the overall war effort -the trick would be managing to do that with legitimate enough excuses and explanations to avoid undue suspicion ... Stalin managed to be plenty tricky and manipulative enough, so responding in kind would be the natural, smart diplomatic route to take)

Plenty of those late-war P-39Qs and P-63s could have been useful in the PTO instead with American or Commonwealth pilots. And use in that theater might have merited more effort to expanding the fuel capacity or switching to a hispano in the hub. (and hell, as it was, both the P-39Q and P-63A had much better better combat radii than the Spitire and the P-63 might have made a more competitive fighter-bomber with its triple wing racks)

Of course, the horrible decisions made by the post-war Labor government in the UK made things a lot worse.




I'll get back to Koopernic's more relevant post regarding engines in a little while. (hopefully)

 

[parsifal]

when war broke out in September, the major players responded in various ways. Almost immediately, even before the outbreak of war between Finland and the Soviets, the Soviets began to place a great deal of pressure on the Finns. All of the nations across Europe and Nth America expressed a great deal of sympathy for Finlands predicament, and each of them offered amounts of support for the Finns in their unequal struggle with Stalin. All except one nation.....Germany, who worked tirelesly to support the Soviets in their aggression at every opportunity. The German foreign ministry were instructed to "play down the Finnish position, play up the Soviet case". Hitler was only major leader who expressed a desire to recognixe the Kuusinen(??) puppet regime. The German intelligenece services began feeding information to the Soviets to assist them in their attempts to enforce a blockade of Finlands Baltic sea trade. The Germans began a policy to apprehend, all Finnish shipping that they could, take it in prize and confiscate the cargoes. They absolutely refused all material aid from passing through territory they controlled , including the shipment of the italian fighters and Hungarian military formations that wanted to go to Finland's aid. The British response was limited, but of greater help to the Finns. They gave the Finns a better than even break with regard to the Allied Control Commission activities, allowing the importation of military cargoes into Finland when all other non- aligned nations were being denied such access. They cleared for export engine and spare parts for the Finnish Military equipment, Blenheims and Gladiators mostly, at a time when even allies like Australia were disallowed such access. Its more than a bit rich to argue that the Germans were sympathetic to Finland's position, when in fact they were doing everything they could to hurt Finland.

From March 1940 until Finland's joining with the Axis, the British protected and allowed free movement of Finnish shipping which provided the Finns with considerable external revenue. Not all of this shipping was used for allied purposes, much of it was used for the transport of non-military neutral cargoes. It was still the target of unrestricted warfare by the Germans and still afforded whatever protection could be undertaken by the RN. Hardly the actions of a nation bent on Finland's destruction. And for Germany, hardly the actions of a nation acting in good faith with the welfare of Finland paramount in German interactions with the Finns.

Churchills DoW on Finland was about the most apologetic declaration that could be made. Britain was desperate, and had a new found ally in Soviet Russia. Allowing German troops into Finland forced the British to do what they did. The following is a memo from Churchill to the Finns explaining what they were doing and why. After apologising for the declaration of war to the finns, Churchill made it clear that it was the newly forming alliance with the Soviets that was forcing his hand, and stated that no real action likely to prejudice Finland would be taken provided the Finns pulled up at the 1939 borders. This was not a formal agreement, but it was an understanding that both sides observed.

By the time the Tehran conference in 1943, the emergency for Britain was receding and Britain was able to lead the way in protecting the interests of Finland. Stalin had forcefully wanted to occupy the whole of the nation, the US was ambivalent about the issue (brought about by ignorance really of Soviet methods), but Churchill ferociously advocated that no Soviet occupation was to occur. Stalin was reluctantly made to accept that position, and when the peace treaty was negotiated a year later, it was largely on the principals that Churchill had been able to secure at Tehran.

Prior to the capitulation in September '44, Germany held the Finns to ransom, in exchange for vital military equipment, the Fins were being asked to fight to the death against the Russians. The Finns were also held to ransom by the germans to enter into a formal alliance with them. Skillfully the Finns saw the writing on the wall and refused. It probably saved their country from destruction and occupation, but it also clearly demonstrate the German duplicity and machiavellian behaviour.

In the meantime Soviet demands were that Finland drive out their erstwhile allies, In the beginning there was a "gentlemens agreement" that allowed the peaceful evacuation of northern Finland by the Germans. Like most things, the germans again demonstrated they could not be trusted as they unsusccessfully attempted to occupy certain Finnish islands in the Baltic and implemented a scorched earth policy in Lappland. Hardly the stuff of a trusted ally.

Finland has itself to thank for its survval as a nation, but it also has a debt to the British for giving them some manouvre room as well. Without that assistance, Finland would not have survived Stalins aggression.

 

[kool kitty89]

Jumo 210 on the PZL.38

Bramo 323 on the PZL.37

The Best Polish engine for 1939 was probably a Daimler Benz DB600 or Jumo 211.

The problems between Poland and Germany were not so insuperable.

Those would be more relevant if war ... or continued uneasy cold conflict (including more grudging treaty agreements or even alliances of sorts) might not foster very favorable trade or at very least make licenses more difficult. Diamler Benz engines also tended to be more complex and problematic to build, so the Jumo 211 would seem more realistic.

In terms of 1937/38 production designs (with development starting in the 1934-35 period), the Jumo 210 might be a consideration, but power would be in the same class as the Kestrel and indeed the Mercury VI.2S the Poles already had in production (the latter with more drag but also lower weight and better altitude performance). Either engine, or both, might be more attractive to import rather than attempt any sort of license. The Hispano 12Y would be attractive for license if they pursued it early, but for imports it might have suffered the same supply problems as the Gnome Rhone engines.

The BMW 132 and Bramo 323 might be useful as potential substitutes for the Mercury and Pegasus. The 132 was larger in diameter than the Mercury, but in the same power class (both for the older Mercury VI and the new VIII) while the Bramo engine would be more useful as a Pegasus substitute. (the 2-speed versions would be later, so they'd have the 900 ps take-off A/B and 1000 ps take-off C/D with poorer altitude performance but better specific fuel consumption -the latter seems the better bomber/transport engine if inferior to the Pegasus)

The BMW 132 might have been an interesting consideration as a fighter engine, though. With the existing Mercury tooling, not as attractive to license than the Mercury VIII or GR engines for that matter, but useful as an imported engine and potentially a more reliable source than GR. I'm not sure if there were any 132 models with altitude performance competitive with the Mercury VIII, though.

If a more favorable alliance with Germany had been struck, and stronger anti-Soviet provisions been made in general (again Allying with Romania and Finland at the very least seems significant) then licensing the Jumo 211 would seem the logical choice in 1939. However, the tool-up time would still seem complicated compared to the various radial engines using the Mercury bore and stroke, so the Mercury VIII would seem the good short-term option with the Jumo as a followon front-line design. (possibly imported too -and the Germany manufacturing situation would be different if war hadn't broken out in 1939 ... or if it had been the Winter War that sparked things off with no German invasion of Poland)

Hitler was an Austrian though a pan-German nationalist. As a southerner he had no particular truck with the Poles. He had in fact offered a Polish-German friendship treaty that was in a thinly disguised anti Soviet military treaty. His concern was the economic viability of marooned North Prussia and the German Hanseatic Port of Danzig which was of enormous cultural significant. To secure this he wanted a rail and freeway link 'right of way' to Danzig in return for the anti soviet pact. The treaty foundered on Polish instance on customs inspections (which would have destroyed the viability of the free trade zone). Other tensions included the disenfancshiment of ethnic German land owners in Poland and a continuous level of ongoing low level anti German hate crime (about 2000 to 4000 victims before the war) which Hitler seemed prepared to stomach.

Would anti-German sentiment have played into the politics surrounding Hitler's proposed Alliance? I don't mean anti-Nazi sentiment or distrust of Hitler and his regime, but general prejudice against ethnic Germans detracting from any sort of 'friendship' even if more strictly a military alliance.

Hatred (or less passionate disdain) and poor, irrational decisions tend to go together (and tends to breed conflict, including war), so it wouldn't be that surprising if there was at least some relation there.


Of course, this would have all been much simpler if Stalin had made the first move and made anti-Soviet alliances much more obviously necessary. (along with associated compromise) Germany would make an objectively safer ally than the USSR as well ... even considering some hypotentical Polish-Soviet alliance the biggest resource the Soviets had was manpower, so pressure to allow Soviet troops to enter Poland as support could be very high. (and much more dangerous than having only material resources being provided as assistance)

The HS12 series was slow in developing and no better than the Italian water cooled inlines of around 860hp and MS460 and DW520 used by German training squadrons were universally hated for their viscous unannounced stalls and spins. The French simply had not had the time to debug these things. The Swiss made them work though, after a few years.

Back in the early 1930s, compared to licensing the Mercury, the 12Y might have been attractive, but then so might the Fiat A.30 and both were available earlier than the Jumo 210 and were more powerful. (eventually more powerful than the Kestrel as well)

The decision would have to be made to go with water cooled V-12 engines rather than 9 cylinder air cooled radials with the original PZL P.11 design to make that feasible, but neither of those V-12s were available when the Mercury IV was licensed for the P.11, so you have the Mercury licensed and tooled up in the early 1930s and then the added overhead of a totally new (but not that much better) engine tooling up in the mid 1930s. Switching to the Mercury VI in 1934 made more sense for that reason, as did the Mercury VIII but they were just too slow and late to shift to the latter.

The Fiat A.22 and A.24 are in the right size range and were around in the late 1920s, but neither was built in large numbers and I don't think either was ever supercharged. Given the fact Fiat switched to the radial A.74 in a fairly similar size and performance class to the 14K and late model Mercury, it seems to point to the Poles making a good choice with the Mercury back in 1931, it might have been better if they'd just stuck with it with a bit more focus. They could try to get more out of the 645 hp Mercury VI as well as pushing for Mercury VIII production sooner, possibly at the expense of Pegasus production. The Mercury VIII could and did make a decent bomber engine too and the PZL.37 was already close to being a good fast bomber and recon aircraft that could have been optimized more around the more limited take-off power of the Mercury VIII to take advantage of the lower weight, drag, and much higher critical altitude. (very well might have beaten the Blenheim)


If it was the VVS alone and not the Luftwaffe they were opposing in 1939, the P.11g might have been good enough ... or really just a P.24 re-engined with a Mercury VIII (just need to get that into production sooner). 2 LMGs plus 2 oerlikon FFFs with far better handling and better pilots than Soviet I-16, better performance than the I-15, though the I-153s might have been more trouble. If they'd managed to purchase any Bf 109s (even Jumo powered ones) that obviously would have been very significant, but the cannon-armed P.11s would be more effective against heavier targets.
A 6 LMG armament (2 in the fuselage) might have also been possible for the P.11g or 4 LMGs and 2 cannons. (the latter might not be worth the weight/performance trade-offs, but the 6 LMGs would be a good fighter vs fighter armament and good for strafing)

 

[net_sailor]

They could try to get more out of the 645 hp Mercury VI as well as pushing for Mercury VIII production sooner, possibly at the expense of Pegasus production.

If it was the VVS alone and not the Luftwaffe they were opposing in 1939, the P.11g might have been good enough ... or really just a P.24 re-engined with a Mercury VIII (just need to get that into production sooner).

This effords were taken on late 1935 and abandoned on erly 1936, cause Bristol refuse delivery of Mercury VIII construction drawings for licence production. At this time only few prototype units of Mercury VIII existed, and there were no drawings adequate for mass productions at all. Bristol couldn't make these drawings in reasonable time (the drafting room was a bottleneck of all factories). Poles didn't press too hard - situation on PAF was quite satisfactory. The large number of P.7 were on strength a new P.11a just entered into the service, and P.11c was in sight.

 

[kool kitty89]

This effords were taken on late 1935 and abandoned on erly 1936, cause Bristol refuse delivery of Mercury VIII construction drawings for licence production. At this time only few prototype units of Mercury VIII existed, and there were no drawings adequate for mass productions at all. Bristol couldn't make these drawings in reasonable time (the drafting room was a bottleneck of all factories). Poles didn't press too hard - situation on PAF was quite satisfactory. The large number of P.7 were on strength a new P.11a just entered into the service, and P.11c was in sight.

And the Pegasus XII was available sooner than the Mercury VIII so was the obvious alternative, at least as a bomber engine. I still think a Pegasus powered P.11 would be useful, though performance would probably fall to P.11c levels around 4.5 to 5 km altitude range (at or above the Mercury VI's critical altitude). The Pegasus I think still has a little more power at altitude, but not enough to overcome the added weight and drag of the larger engine.

I'm not sure about the Pegasus XX used for most of the production PZL.37s, was that available any sooner than the Mercury VIII? (if they'd kept pressing for both the newer Mercury and Pegasus designs and the Mercury VIII became available as soon as the Pegasus XX, they could have focused production on that instead) Even with the same power loading limits applied to the PZL.37, its bombload would still be competitive with the Ju 88, better than the Do 17 and much better than the Blenheim, so it doesn't seem like a bad move. (and should make the PZL.37 a better fast recon aircraft) Rough field load limits might bring things closer to the Blenheim's load, but reduced fuel load could partially compensate.


But even with the Mercury VIII delayed and the Pegasus not so good as a fighter engine, attempting to get a license for one of the Gnome Rhone 14K engines would seem a better option. (at least if any had altitude performance close enough to the Mercury VIII to be useful) If none of the 1935/36 14k models in production had performance as good or better than the Pegasus XVIII, then using that engine seems like the better option. (the 14K with similar performance to the Pegasus would still be a better engine given it's nearly 5 inches or 127 mm smaller in diameter)

Lack of a 2-speed supercharger would mean less take-off and low altitude power in all cases, or of course having decent take-off power but poorer altitude performance than the Pegasus. (one bonus for the Pegasus's low-altitude power would be improved initial rate of climb on a fighter)


Also remember that 3500 m isn't far from the critical altitudes French fighters had to deal with in general and all without the benefit of 2-speed superchargers.

 

[net_sailor]

I'm not sure about the Pegasus XX used for most of the production PZL.37s, was that available any sooner than the Mercury VIII? (if they'd kept pressing for both the newer Mercury and Pegasus designs and the Mercury VIII became available as soon as the Pegasus XX, they could have focused production on that instead) Even with the same power loading limits applied to the PZL.37, its bombload would still be competitive with the Ju 88, better than the Do 17 and much better than the Blenheim, so it doesn't seem like a bad move. (and should make the PZL.37 a better fast recon aircraft) Rough field load limits might bring things closer to the Blenheim's load, but reduced fuel load could partially compensate.

Contact for delivery of 3 Pegasus XX engines (two for PZL.37 prototype + spare engine) was signed on March 1937, but licence production started on 1939. Between April and June only 29 of planned 45 pieces were completed, mainly due of lack of some parts delivered by Bristol (not all parts could be fabricated in Poland cause technological limits).

But even with the Mercury VIII delayed and the Pegasus not so good as a fighter engine, attempting to get a license for one of the Gnome Rhone 14K engines would seem a better option. (at least if any had altitude performance close enough to the Mercury VIII to be useful) If none of the 1935/36 14k models in production had performance as good or better than the Pegasus XVIII, then using that engine seems like the better option. (the 14K with similar performance to the Pegasus would still be a better engine given it's nearly 5 inches or 127 mm smaller in diameter)

Generally it would be a good idea, but there was a one small factor I didn't mentioned earlier: the money. Licence agreement with Bristol allow us to fabricate all next generation engines without any additional licence fees! That's why Poles praised for Hercules for the future generation bomber PZL.49 and Taurus for powering the P.50 Jastrząb II project. The only matter was availability of construction drawings. An implementation of new engine on production lines takes about one year. It is acceptable time, when you planning a long term air force development with very limited resources: money and material stocks (ie. more money, cause all aluminium was imported).
Anyway it would be quite wise to develop an "shadow fighter" parallel with controversial PZL.38. The Wilk was technologically advanced, high risk program built around non existing, high performance engines. Fokker D.XXI class fighter constructed around Mercury VIII and without use of strategic material would be a good support.

 

[kool kitty89]

Generally it would be a good idea, but there was a one small factor I didn't mentioned earlier: the money. Licence agreement with Bristol allow us to fabricate all next generation engines without any additional licence fees! That's why Poles praised for Hercules for the future generation bomber PZL.49 and Taurus for powering the P.50 Jastrząb II project. The only matter was availability of construction drawings. An implementation of new engine on production lines takes about one year. It is acceptable time, when you planning a long term air force development with very limited resources: money and material stocks (ie. more money, cause all aluminium was imported).

The license agreement didn't include any royalties, but only a single large sum paid up front? That does indeed seem like an expensive route and if those existing older Mercury VI engines could continue to be built free of additional license royalties, that should certainly be an attractive reason to seriously consider using those engines for newer projects.

Anyway it would be quite wise to develop an "shadow fighter" parallel with controversial PZL.38. The Wilk was technologically advanced, high risk program built around non existing, high performance engines. Fokker D.XXI class fighter constructed around Mercury VIII and without use of strategic material would be a good support.

Given the aerodynamic similarities and what I assume would be similar construction techniques, putting more investment into the PZL.38 earlier might have made more sense than funding the PZL.37 as much as they had IF that fighter had used engines already readily available. A mercury VI powered PZL.38 could potentially be built and tested with Mercury VI.S2 engines even before the PZL.37's Pegasus engines could be imported from Bristol. Building and testing that smaller scale aircraft (which really does seem to be a scaled down PZL.37 in many respects) should be significantly cheaper than the full-sized bomber version while also having less (or no) delay related to engine availability. With engine availability limiting PZL.37 production anyway, it seems like diverting those resources towards building PZL.38s fitted with engines already in production would make plenty of sense.

So even if they thought having advanced bombers was more important than fighters (or fighter-bombers or attack aircraft), there seem like plenty of practical economic reasons the PZL.38 would be more attractive. That said, my 'ideal' suggestion of turning the PZL.38 into a single-seat fighter might be more difficult to promote at the time. (plenty of aircraft developers seemed to like the idea, but most governments seemed to balk at a single seat twin-engine fighter)

Using the Mercury for initial testing of the P.39 would also make sense even if they still planned to use an alternate powerplant for production. I'd honestly expect they'd eventually have just preferred to produce the fighter using the Mercury engine if it was felt a light fighter was actually practical. Something lighter than the D.XXI or P.11c but similarly powered should be more useful than the underpowered Italian and French light fighters, perhaps closer to the VG-33 in concept but maybe not as reliant on wooden construction unless PZL had access to engineers and craftsmen experienced enough to manage that reliably without making it too heavy. (still, compromising to use steel, wood, and fabric where practical and aluminum where most needed should work well as long as they planned on striking a balance from the start -Fokker seemed to manage with the D.XXI)


I also found some interesting translated resources for the P.24 and 14K engines:
Data Sheet PZL P.24A - WiP data sheets - War Thunder - Official Forum (a couple posts later down have lists of speed and rate of climb at various altitudes along with weight and load information )

The posts there cited this archive for the information Musée Safran

The climb rate of the P.24 seems to be a great deal better than what Wiki lists and actually over 1000 m/min in its best altitude range. (which appears to be between 2000 m and 4000 m with best climb at 3000 m at 1091 m/min)

Top speed is 430 km/h at 4250 m and still managing 415 km/h at 6000 m.


I also found this http://digital.library.unt.edu/ark:/67531/metadc63391/m1/10/med_res/
The 14Kfs is listed at having maximum power of 900 hp at 3620 m which drops to 760 hp at 5000 m.

Pursuing a Gnome-Rhone 14Kfs license might have been more useful than the Mercury VIII or Pegasus as both a fighter and bomber engine. (again, common production with IAR would be an advantage there too) And aside from the above suggestion of a light fighter targeting the older Mercury VI, work on the P.50 could have started sooner with a 900 hp engine available that much sooner. (aiming at a wooden wing like the D.XXI would make sense to minimize imported material while re-using as much of the P.24 design as possible and initially using fixed landing gear like the D.XXI -aiming at a 'better' D.XXI alternative that also used existing components and didn't need acquiring a license or importing foreign aircraft seems like a pretty sensible overall objective)


I really think the Gnome Rhone 14N is a bad idea, it's heavier, not all that much more powerful at altitude, available later, and still heavy and powerful enough on take-off to complicate structural stability (and add yet more weight) in the P.50 design.

 

[Timppa]

Finland has itself to thank for its survval as a nation, but it also has a debt to the British for giving them some manouvre room as well. Without that assistance, Finland would not have survived Stalins aggression.

No, British "assistance" was worth a diddly-squat. Where was the assistance to Poland ?
There may been an other factor in the play. I let you figure it out.

 

[parsifal]

Please enlighten me.

At tehran the focus of the western allies were the future military operations, in particular the second front and securing Soviet entry into the pacific war. The western alliance was still fighting for survival in many ways, or at least trying to do all possible to maximise the chances of its success in the up coming cross channel attack. Nevertheless, both the US and Britain did what they could to try and curb Soviet aggression. Undertakings were extracted from Stalin to allow self determination elections in Poland and the Baltic States. Stalin was made to agree to a pull out of Iran at wars end, and to support the Turks if they entered the war. Because of the concerns about the cross channel attack, Stalin was able to extract a secret agreement from the allies about Polish borders. basically they were to remain at the partition line of 1939, or as Churchill called it the curzon line ( a reference to the agreement made in 1920, but not really sticking to those borders), in exchange for a co-ordinated offensive by the Russians to throw the Germans off guard.....the offensive that led to the destruction of AGC. In exchange for entry into the pacific, the Russians were promised the Kuriles and control of Manchukuo, something they later pulled back away from.

These were all critical issues for the west and they were prepared to make compromises of principal to secure the best co-operation they could from Stalin. The west was prepared to make concessions where needed to secure Soviet co-operation. Poland, the Baltic States or indeed Finland were not of critical importance to western interests of 1944. Normandy, minimising allied casualties, securing Russian co-operation were....I have no problem in understanding the logic behind that, and i certainly would give no credence to a national of a country that had co-operated fully with its axis partners and then expects to be able to occupy some form of the moral high ground because the west did not break or threaten a military alliance that was critical to them. You, and your country are in no position to lecture me, or countries i identify with, in any way. You should just hang your head low and be thankful that we did win.

As it turned out, in Eastern Europe, the Soviets failed to honour their committments in Poland or Baltic States, but they did honour respect for the turks, they did pull out of Iran and they never made a serious effort to undertake a full military occupation of Finland. They were content with Finnish capitulation of their foreign policy freedom of action (though to finlands credit, it never participated in joint military excercises as had been expected by the Soviets under the 1948 peace agreement). The pattern emerging is that on the flanks of the main front, the Soviets were prepared to make concessions. In the case of Finland, in Soviet eyes, there was only Sweden and Norway beyond, but in the case of of Poland there was Germany, who twice in 30 years had attacked Russia. The Russians were never going to concede Poland as anything except direct domination by the Soviet political and military establishments. There really was nothing the British could do about that, though they did not realize just how bad things would be. In the case of Finland, the suggestions made by churchill as forcefully as he could make from a position of weakness, and with the knowledge also that there were far more important issues also at stake, were considered and accepted by Stalin. He could have chosen to ignore those agreements if he chose, just as he did in Poland, but there wasnt the gain in it for the USSR that there was in Poland. I think, however that by stating the case for Finland at tehran, Churchill made the wests position clear, and Stalin accepted that because there wasnt much to gain by breaking the agreement. He got economic dominance through the reparations, he got political non- alignment through the peace treaty, and he never really had any military threats to worry about. In central Europe the situation was fundamentally different, so all the scheming by Churchill could not deviate the Soviets from that path of direct occupation and intimidation.

With regard to Poland, it was beyond Britains power to avert the subversion of Poland both in 1939 and in 1945. But britain did more to at least try and protect Poland than Finland has ever done. All Finland did was side with Germany. Too precious to get their own hands dirty but happy enough to side with a regime bent on the extermination of millions. That, sadly, made her an enemy. And Finland did what to help anyone but the germans and themselves?

 

[Glider]

Helo, gents,
What tecnological paths hould`ve been undertaken by the Polish air force in the 1930s, in order to be better prepared for the September war in 1939? Not that it would`ve changed the outcome, but just to give Polish air crews better chances once airborne.

To give the aircrew the best chance the only option that I can see is simply to buy as many Hurricanes as they can get. The main Luftwaffe fighters would be the Me110 and the Me109D. The 1939 Hurricane has a clear advantage over the 109D and it has a good chance against the Me110.

 

[fastmongrel]

To give the aircrew the best chance the only option that I can see is simply to buy as many Hurricanes as they can get. The main Luftwaffe fighters would be the Me110 and the Me109D. The 1939 Hurricane has a clear advantage over the 109D and it has a good chance against the Me110.

What date is the earliest Hawkers could deliver Hurricanes to the Poles and would the Air Ministry allow any delays to RAF deliveries to equip the Polish AF. Also just the Hurricanes arriving in Poland doesnt mean they could go straight into service did the Poles have the time to get Pilots and ground crew trained for a useful number of Hurricanes into service.

 

[Greyman]

What date is the earliest Hawkers could deliver Hurricanes to the Poles and would the Air Ministry allow any delays to RAF deliveries to equip the Polish AF. Also just the Hurricanes arriving in Poland doesnt mean they could go straight into service did the Poles have the time to get Pilots and ground crew trained for a useful number of Hurricanes into service.

From posts I made in this thread a few years ago:

The Poles had struck a deal with Britain and France in March '39, and had received one Hurricane for evaluation purposes before the invasion. Nine more were en route, but it was over before they could be delivered.

Canada began receiving Hurricanes September 1938, South Africa by November 1938, Yugoslavia by December 1938 ...