WI: A strong Polish interceptor, 1939

Typical I cant find the info, I never can when I try to go back and read again. iirc it was a problem with the empty cases jamming up the works manouvering stopped them falling freely away. Hopefully someone with more or the correct info will come along.
Czechoslovaks were manufacturing also cannon versions of HS 12 mounting them into Avia B-534'. I don't remember reading about technical problems but more about slow cannon production so some of cannon version B-534s were getting machine gune istead of cannon. They end up wit 3 MM instead of 4 MG in regular planes.
 
It is Stuttgart, indeed.

...
It was a function of deliberate design philosophy, to enable an engine to grow in capabilities.

Is that a result of an independent study, or an abstract from an essay of a person (or people) involved, since we know that a 'prop gun' capability does not necessarily means sacrifice in performance?
 
Czechoslovaks were manufacturing also cannon versions of HS 12 mounting them into Avia B-534'. I don't remember reading about technical problems but more about slow cannon production so some of cannon version B-534s were getting machine gune istead of cannon. They end up wit 3 MM instead of 4 MG in regular planes.

Its possible I am mixing things up with either British or US problems getting the HS404 into service.
 
Is that a result of an independent study, or an abstract from an essay of a person (or people) involved, since we know that a 'prop gun' capability does not necessarily means sacrifice in performance?

I probably read it somewhere 50 years ago. I believe that Rolls Royce engineers thought that the up-right vee without provision for motor cannon was the best promise for best performance. They also fervently dismissed pressure carbs and direct injection, which proves that they weren't always right, in the end. On the other hand, one of the most highly rated German prop fighters was the FW-190D-9. Lacking prop-gun capability doesn't necessarily mean a lack of effectiveness.
 
The Poles were creating a bomber-destroyer version of the PZL-37 "Los" light bomber called the PZL-38 "Wilk" ('Wolf'). IIRC there only mock-up's available in 1939, the prototype was still under construction.

Something like this could have really done some damage to German bomber streams...
 
The Poles were creating a bomber-destroyer version of the PZL-37 "Los" light bomber called the PZL-38 "Wilk" ('Wolf').
PZL-38 wasn't a version of PZL-37. It was -mostly- a scaled down PZL-37.

IIRC there only mock-up's available in 1939, the prototype was still under construction.

PZL-38's first flight was in 1938. But it was overweight and underpowered.

Later refinements of the concept were PZL-48 (with GR14M engines) and PZL-54 (with HS-12 engines). None flown before 1939.

On another note:

1. Getting HS-12 engines for Polish airforce is unlikely - OTL Poland was interested in that engine as early as 1929 (PZL-1 used HS-12Lb), but Hispano-Suiza wanted too much money for licence.

2. You can change the PZL-23 or take a different design instead of it, but a bomber/scout was going to be aquired by Polish airforce by mid-1930s, because otherwise it'd be forced to fly on... Potezes XXV and Bregeuts XIX.

3. In Polish practice, it took normally ~4 years from starting an airplane project to fully rearming the frontline with a resulting plane. Please keep this in mind - if you want a modern fighter equipping majority of 1939 Polish fighter force, program to aquire it should start no later than in 1935, and first flight no later than 1937.
 
The starting point has to be domestic aero engines. Then the doctrine and after that an airframe to use them can follow. With PZL having negotiated good licences from Bristol it is the only show in town. Whilst they had option upon the Taurus and Hercules neither was going to be ready in 1939 (even Bristol had troubles) so the only options are Mercury and Pegasus. The Mercury has topped out and can only get the performance with a lightweight airframe. The A6M went down that road quite successfully for the period. Or the Pegasus which is similar in weight and diameter to the R-1820 with only a little more power than the Mercury but more torque to drive a bigger or more aggressive airscrew. With Polish petrol it is no use looking at 100 octane and twin stage supercharging so the best power levels of the late Pegasus and R-1820 are out of reach. A reliable 950bhp is about right whereas the Mercury in Poland in 1939 would be running hard to maintain even 850bhp. Thus the only engine option for a fighter is the Pegasus. If Poland can summon the courage to say that it needs to concentrate on fighters to allow it's ground forces to act then a viable opposition to the Luftwaffe is feasible. I would add that, if they were prescient and allowed their fighters to act in close support as in later WW2 it would seem a bonus but 1939 thinking would inevitably divert them to that at the expense of the primary role.

For an airframe the IAR 80 gives us a OTL model of what can be done so we are looking at something like a PZL 50 or IAR 80 but two years earlier with a Pegasus engine and guns larger than 7.92mm. The Belgians had a nice 13.2mm Browning for example which was well within the ability of the Polish arms industry to make. Four of these would do the trick in 1939 and there are assorted similar types in the same class although they had experience with wing mounted 20mm Oerlikon FF cannon.

In parallel an investment in a part time ground based warning system that had dedicated communications to maximise the use of the new fighters from the existing dispersal airfields.

Meanwhile they are using Mercuries in their new AH tank................
 
I probably read it somewhere 50 years ago. I believe that Rolls Royce engineers thought that the up-right vee without provision for motor cannon was the best promise for best performance. They also fervently dismissed pressure carbs and direct injection, which proves that they weren't always right, in the end.

Thank you.

On the other hand, one of the most highly rated German prop fighters was the FW-190D-9. Lacking prop-gun capability doesn't necessarily mean a lack of effectiveness.

That kinda misses my point. It is one thing to design an aircraft around a 750-850 HP engine, a cannon, and expect it to perform. A fighter with 1750-2000 HP is a whole another ball game.
 
That kinda misses my point. It is one thing to design an aircraft around a 750-850 HP engine, a cannon, and expect it to perform. A fighter with 1750-2000 HP is a whole another ball game.

You might also realize that I get your point. If someone builds a 36L engine producing 860 hp. with room for a gun, that's a good idea. If someone else builds a 26L engine producing 1,030 hp, but it doesn't take a cannon, that's also a good idea. If someone builds a 34L engine with 1100 hp, and the available cannon doesn't work until the BoB is over, that's not that good of an idea. The Yak-9T was perhaps the most stellar performer in this regard, except that the cannon wrecked the a/c. None of this helps Poland, which should have developed indigenous industries to produce undercarriage, propeller, hydraulics, and aero engines, as well as myriad other products, and done it much sooner so we wouldn't have to discuss how they couldn't have what they needed when they needed it because nobody else could have supplied it either, except maybe Germany,at that critical moment.
 
You might also realize that I get your point. If someone builds a 36L engine producing 860 hp. with room for a gun, that's a good idea. If someone else builds a 26L engine producing 1,030 hp, but it doesn't take a cannon, that's also a good idea. If someone builds a 34L engine with 1100 hp, and the available cannon doesn't work until the BoB is over, that's not that good of an idea. The Yak-9T was perhaps the most stellar performer in this regard, except that the cannon wrecked the a/c. None of this helps Poland, which should have developed indigenous industries to produce undercarriage, propeller, hydraulics, and aero engines, as well as myriad other products, and done it much sooner so we wouldn't have to discuss how they couldn't have what they needed when they needed it because nobody else could have supplied it either, except maybe Germany,at that critical moment.
Even Czechoslovakia of which at least Czech lands had very good industry but and pretty solid awronautic industry - at least 4,5 different companies bought HS 12Y license. Development to 1000 HP was done locally but not finnished till late 1939. Retractable undercarriege development was late etc. And especially government started to found everything to late... Common practice in Europe and US at the time. I guess government's would be able to fund it but nobody wanted to invest to much to early I guess in order not to end up with bunch of obsolete airplanes.
 
Even Czechoslovakia of which at least Czech lands had very good industry but and pretty solid awronautic industry - at least 4,5 different companies bought HS 12Y license. Development to 1000 HP was done locally but not finnished till late 1939. Retractable undercarriege development was late etc. And especially government started to found everything to late... Common practice in Europe and US at the time. I guess government's would be able to fund it but nobody wanted to invest to much to early I guess in order not to end up with bunch of obsolete airplanes.
If Poland joined the Little Entente, and they developed their industry collaboratively, you might be able to better afford to develop good kit. Also, if the central European nations stood together, they'd be a lot tougher for any enemy to take on.
 
Regarding the Bistol Pegasus i too was thinking that it could be an altrnative fighter engine, but as far as i can read not a single fighter aircraft in the world was fitted with a Pegasus - but correct me if i'm wrong. I can only remember about two polish projects of gull-wing fighters with Pegasus engines, the Z-17 and Z-18.

So it still looks like the best reasonably possible course of action is to get the GR14K and later N for the PZL-23 and 46, PZL-37 and PZL-50 (the GR engine always offered much increased speed when used on these designs), and the HS-12Y for the PZL-38 and PZL-55. As far as national engines are concerned, they should immediately drop the useless Foka and focus on a modern 12 cylinder V12 based on HS-12Y of say 1200HP and the 14 cylinder Legwan of 1400-1600HP.

Just as a sidenote, not that the GR14K and it's derivatives are the best, but it seems to be the best choice reasonably available in the mid-1930s. Romania bought the engine in an under the table deal (read corruption), they have struggled from the beggining with it's unreliability, defects and low TBO, but the indigenous versions gave valuable service on the 800 or so airframes that were powered by it before and during WW2 (not counting here the GR9K and 7K)
 
You might also realize that I get your point. If someone builds a 36L engine producing 860 hp. with room for a gun, that's a good idea. If someone else builds a 26L engine producing 1,030 hp, but it doesn't take a cannon, that's also a good idea. If someone builds a 34L engine with 1100 hp, and the available cannon doesn't work until the BoB is over, that's not that good of an idea.

The HS engine in conjuction with HS or Oerlikon cannon worked, and that was the only combination I've suggested for the Polish. I don't remeber suggesting the DB 601A with motor cannon for them.
Of course, a 1030-1100 HP engine gives options that 860 HP engine cannon offer.

The Yak-9T was perhaps the most stellar performer in this regard, except that the cannon wrecked the a/c. None of this helps Poland, which should have developed indigenous industries to produce undercarriage, propeller, hydraulics, and aero engines, as well as myriad other products, and done it much sooner so we wouldn't have to discuss how they couldn't have what they needed when they needed it because nobody else could have supplied it either, except maybe Germany,at that critical moment.

The Polish were already producing propellers, retractable U/Cs & hydraulics, aero engines before the war.
BTW - it was 45mm cannon on the Yak-9K that wrecked the a/c, they got along with the 37mm equipped version.
 
Regarding the Bistol Pegasus i too was thinking that it could be an altrnative fighter engine, but as far as i can read not a single fighter aircraft in the world was fitted with a Pegasus - but correct me if i'm wrong. I can only remember about two polish projects of gull-wing fighters with Pegasus engines, the Z-17 and Z-18.

So it still looks like the best reasonably possible course of action is to get the GR14K and later N for the PZL-23 and 46, PZL-37 and PZL-50 (the GR engine always offered much increased speed when used on these designs), and the HS-12Y for the PZL-38 and PZL-55. As far as national engines are concerned, they should immediately drop the useless Foka and focus on a modern 12 cylinder V12 based on HS-12Y of say 1200HP and the 14 cylinder Legwan of 1400-1600HP./QUOTE]

I am reminded of an anecdote:
Why don't they use robertson screws in cars?
Because they are for furniture.

Bristol made the Pegasus and called it the bomber engine. They made the Mercury, and called it the fighter engine. The difference was about 3 inches. When they only made the Jupiter, it was just an engine.

The Soviets made use of HS12Y tech in producing engines with one more valve, and got 1100 hp. and more, eventually. Soviet fighters didn't exactly swamp the Germans in 1941. It took considerable numbers to swamp the Germans, and Poland didn't, and wouldn't have such numbers, in 1939.
 
If Poland joined the Little Entente, and they developed their industry collaboratively, you might be able to better afford to develop good kit. Also, if the central European nations stood together, they'd be a lot tougher for any enemy to take on.
They could. I believe I read somewhere Avia had some factory in Poland.
 
The Polish were already producing propellers, retractable U/Cs & hydraulics, aero engines before the war.

According to wiki, the P.50 testing had to wait while a Mercury VIII engine was delivered from Britain, and they also had to wait while George Dowty whipped up an undercarriage, in Britain, while production undercarriage was to be produced by Avia. Is Avia a Polish company?
 
The PZL-50 interceptor project began late in 1936. There were flying prototypes in early 1939, and variants powered by Gnome-Rhone 14N21 and Bristol Taurus engines were planned. These planned variants could reach 350mph, roughly equivalent to the Bf-109 E fighter of the Luftwaffe. IRL, the Polish PZL 11 interceptors, the aircraft they had in numbers at the time, were no match for the Luftwaffe, being even slower than German bombers, much less Bf 109 fighters.

But what if the Poles had been able to quickly run the PZL 50 program through the design processes and produce a powerful interceptor in time to supply the air force for the defense of Poland? While the Wehrmacht would likely still be able to overcome the smaller Polish army, if the skies were more fiercely contested by more modern machines, the Poles may have been able to put up a much more effective fight, and perhaps delay Hitler's rapid expansion through Europe following their collapse.

The Jasztrab would have been equal to the Bf-109 if the Poles had managed to work out the Kinks, that's the big issue, PZL was having problems with the Engines and by the time of the Defensive war, only one prototype was airworthy. . .

Supposedly if PZL had decided to either scale back or cancel their focus on the Karas light bomber, it's possible that the Jasztrab could have been ready by the time of the war, the question though is how many they can produce and will it be enough. Remember, the Poles were rather highly trained pilots, and they had amassed a truly staggering amount of Anti-Air Guns before the war. This resulted in them downing one full quarter of the luftwaffe during the defensive war. They should be capable of doing some more damage to the Luftwaffe ITTL.

The problem is one of production. The Western and Central Bits of Poland were the Industrialized ones, with a large number of industrial centers close to the German Border, this ensures that large sections of prduction will be captured or destroyed in the initial invasion. The Poles also have to worry about producing enough 7TP Tanks to help out against Germany, IOTL by the time of the Invasion, they only had 250 7TP light Tanks in service with the army, and though the 7TP was better than the Panzer II, having Comperable Armor and a heavier gun, it was outclassed by the Panzer III. Not only does Poland also need production for Tanks, but for the new Mors Sub-machine guns and 38M Semi-Automatic Rifles that had just finished testing in June. There just isn't enough production to go around unless the Poles decide to invest in Industry earlier than they Did IOTL, they started industrializing more heavily in 1936, but they really needed to begin earlier to get their production capabilities up to snuff.
 
The Jasztrab would have been equal to the Bf-109 if the Poles had managed to work out the Kinks, that's the big issue,



I wouldn't say that the Jasztrab proved that it would have been equal. It was expected to be equal, and it was disappointing. Even the IAR 80 could not be said to be equal. Just not embarrassingly unequal.
 
I wouldn't say that the Jasztrab proved that it would have been equal. It was expected to be equal, and it was disappointing. Even the IAR 80 could not be said to be equal. Just not embarrassingly unequal./QUOTE]

worth noting the Messerschmitt is usually held as the benchmark of the time, everything is always compared to the 109. I feel we should take a look at the Jasztrab against other fighters of similar nations. Perhaps the Yugoslav Ikarus IK-3, or the Romanian IAR.80 as has been mentioned on this board. Even the D.520, I feel, would be a good comparison for performance. There is no doubt in my mind however that regardless of the PZL 50's degree of inferiority to the Bf-109, it would still give those Polish men a far better chance in the air than PZL 11
 
The Yugoslavs had a pretty substantial air force, including a large number of those benchmark 109Es and Hawker Hurricanes and just a handful of IK-3s. They were suffering a similar lack of early warning and fighter control, again against a vastly larger force. They lasted 11 days.
 
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