Topic: Could Poland have beaten Nazis if ......?

[Topspeed]

You have to check the B-model data...530 kph.

Alas, I cannot as no P50B's was ever built, let alone flown. There cannot, therefore, be any data for it. Indeed only the first protoype ever took to the air. Thus any 'data' for the P50B is purely wishful thinking. Given that the expectation for the P50/i prototype was that it would achieve a speed of at least 500 kph, illustrates how far short reality could fall below expectations. While the P50/i supposedly achieved a speed of 490-500 kph after syngnificant reworking of the design, this was still significantly behind that of the BF 109.

The picture displays B-model....apprently not with 1150 hp intented engine.

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 P.50B (estimated maximum speed 560 km/h (350 mph)[1]) or 1,150 hp Bristol Taurus III or IV for the Polish Air Force (estimated speed 530 to 560 km/h (330 to 350 mph)).

https://en.wikipedia.org/wiki/PZL.50_Jastrz%C4%85b

[paulrward]

Hello All :

Top Speed of a PZL P50B with an 1150 hp Taurus would have been appx 298 mph,
or 475 kph.

Respectfully :

Paul R. Ward

[Topspeed]

Hello All :

Top Speed of a PZL P50B with an 1150 hp Taurus would have been appx 298 mph,
or 475 kph.

Respectfully :

Paul R. Ward

Your estimate is based on ...what ?

[gebhk]

Hi Topsapeed

The picture displays B-model....apprently not with 1150 hp intented engine.

Alas no, the above photo is of the P50/II prototype. This was to be the test bed both for the improved P50B production version and the next gen P53 "Jastrzab II". A Gnome Rhone engine was planned for the P50/II prototype and the GR-14 Meteor, PZL Waran or Bristol Hercules were under consideration for the P53. Although it counldn't have been known in 1939, the Bristol Taurus was never going to be a viable option. AFAIK it was never offered for general sale because of its reliability problems and therefore only used on a few planes (notably Bristol's own Beaufort and the Fairey Albacore) and by and large only when the preferred Pratt & Whitney Twin Wasps were unavailable in adequate numbers. By the time the reliability issues had been ironed out, the Taurus was of inadequate output for the new generations of aircraft coming on line. Thus a Jastrzab with a Taurus engine was never going to happen.

In summary, current evidence is for the commencement of the construction of 7 units. Of these only one prototype was completed and flew (the P50/I)
The second, another prototype (the P50/II) may have been completed or not, but never flew.
Construction of 5 units of the pre-production sub-series of the first series (P50/A) was commenced but none were ever completed.
No P50B were commenced, let alone completed.

Thus the only reliable data is for the first tests of the first prototype which preformed on a par with the P-24 and less well (as a fighter!) than the Los bomber. After various improvements, it may have reached a top speed of around 500 kph, however almost certainly in a shallow dive rather than in level flight. In any event with the best spin on it, it was still significantly inferior to the BF109 and, given the fundamental flaws of the design, it was never going to be anything else.

[paulrward]

Hello All :

Mr. Topspeed asked :

Your estimate is based on ...what ?

Basic math. If you know the top speed of an aircraft with a given horsepower, it is fairly
easy to compute how fast it will go with an increase or decrease in power, assuming the
static and dynamic coefficients of drag do not change, ie, that you are not significantly
increasing or decreasing the frontal area, wetted surface, or lift-drag coefficients of
the wing.

You can find this Online, and if you want, there is an Aeronautical Engineer named 'Greg',
who has a site on YouTube called Greg's Airplanes and Automobiles, which has
numerous videos, all well done, which can talk you through how to do some of these
calculations. I highly recomend his site if you want an Engineer's perspective on how
things work on an airplane.

Respectfully ;

Paul R. Ward


P.S. - For years, I had seen figures quoted regarding the Heinkel He 219's top speed,
giving it a figure on the order of 420 MPH. I doubted this very much, considering
the crude surface finish of the aircraft, the ' suitcase ' design of the fuselage, the high
drag shape of the tail, and the built in headwind of the frontal radar antenna.

So, I spent a few days, did a lot of math, and came up with a figure of about 360 MPH
as a top speed, assuming both engines are working up to snuff and there were no
technical issues with the aircraft.

So, where did the figure of 420 MPH ( which you can find in Wikipedia ! ) come from ?

Well, the post war Allied evaluations of several captured He 219s gave top speeds,
using American gasoline, of about 365 MPH. At some point, someone apparently
translated that figure into Metric, ( MPH to KPH ), but, instead of using the statute
miles conversion, used the Nautical Miles Conversion, increasing the speed
by a factor of about 1.15.

Then, someone else converted that metric KPH back into MPH, and used the statute miles
conversion factor, and, voila, 365 MPH became 365 KnPH, which became 675 KPH,
which became 419.3 MPH ! And that's where the 420 MPH figure came from - sloppy
conversion - probably done by a history major.....


Do you want to know why Engineers use the Metric System ? Well, if you are measuring
liquids using the non-metric English System, then :


2 Cups make a Pint
2 Pints make a Quart
4 Quarts make a Gallon
4.5 Gallons make a PIn
2 Pins make a Firkin
2 Firkins make a Kildirkin
2 Kildirkins make a Barrel
1.5 Barrels make a Hogshead
2 Hogsheads make a Butt,
and 2 Butts make a TUN !


Or, you could just stick with Liters......

[gebhk]

assuming the static and dynamic coefficients of drag do not change, ie, that you are not significantly increasing or decreasing the frontal area, wetted surface, or lift-drag coefficients of the wing.

And herein the rub. Without going into the reasons why, the P50 was a rush job for Jakimiuk. Not to put a fine point on it, P50/I was a dog's dinner with a lot of 'off the shelf' and therefore inevitably dated solutions which worked insofar as the plane was done and could fly but, among other things, much overweighted it and there were some evident foul-ups with the engine installation and such-like, all of which which resulted in the disappointing initial performance. Corrections of some of these details resulted in a, reportedly, much better performance in the second round of tests, even without a bigger engine. The contemporaneous 'estimations' of its future performance where not just based on upgrading the engine but also on a bunch of improvements to correct said foul-ups, reduce the overall weight and reduce drag.

[Topspeed]

Hello All :

Mr. Topspeed asked :

Your estimate is based on ...what ?

Basic math. If you know the top speed of an aircraft with a given horsepower, it is fairly
easy to compute how fast it will go with an increase or decrease in power, assuming the
static and dynamic coefficients of drag do not change, ie, that you are not significantly
increasing or decreasing the frontal area, wetted surface, or lift-drag coefficients of
the wing.

You can find this Online, and if you want, there is an Aeronautical Engineer named 'Greg',
who has a site on YouTube called Greg's Airplanes and Automobiles, which has
numerous videos, all well done, which can talk you through how to do some of these
calculations. I highly recomend his site if you want an Engineer's perspective on how
things work on an airplane.

Respectfully ;

Paul R. Ward


P.S. - For years, I had seen figures quoted regarding the Heinkel He 219's top speed,
giving it a figure on the order of 420 MPH. I doubted this very much, considering
the crude surface finish of the aircraft, the ' suitcase ' design of the fuselage, the high
drag shape of the tail, and the built in headwind of the frontal radar antenna.

So, I spent a few days, did a lot of math, and came up with a figure of about 360 MPH
as a top speed, assuming both engines are working up to snuff and there were no
technical issues with the aircraft.

So, where did the figure of 420 MPH ( which you can find in Wikipedia ! ) come from ?

Well, the post war Allied evaluations of several captured He 219s gave top speeds,
using American gasoline, of about 365 MPH. At some point, someone apparently
translated that figure into Metric, ( MPH to KPH ), but, instead of using the statute
miles conversion, used the Nautical Miles Conversion, increasing the speed
by a factor of about 1.15.

Then, someone else converted that metric KPH back into MPH, and used the statute miles
conversion factor, and, voila, 365 MPH became 365 KnPH, which became 675 KPH,
which became 419.3 MPH ! And that's where the 420 MPH figure came from - sloppy
conversion - probably done by a history major.....


Do you want to know why Engineers use the Metric System ? Well, if you are measuring
liquids using the non-metric English System, then :


2 Cups make a Pint
2 Pints make a Quart
4 Quarts make a Gallon
4.5 Gallons make a PIn
2 Pins make a Firkin
2 Firkins make a Kildirkin
2 Kildirkins make a Barrel
1.5 Barrels make a Hogshead
2 Hogsheads make a Butt,
and 2 Butts make a TUN !


Or, you could just stick with Liters......

I don't think polish engineers could be so bad that they miss 85 kph in their estimates.

870 hp Fiat G.50 went 470 kph....and was an aerodynamic pig compared to sleek closed cockpit PZL 50B.


https://en.wikipedia.org/wiki/Fiat_G.50_Freccia

[Topspeed]

assuming the static and dynamic coefficients of drag do not change, ie, that you are not significantly increasing or decreasing the frontal area, wetted surface, or lift-drag coefficients of the wing.

And herein the rub. Without going into the reasons why, the P50 was a rush job for Jakimiuk. Not to put a fine point on it, P50/I was a dog's dinner with a lot of 'off the shelf' and therefore inevitably dated solutions which worked insofar as the plane was done and could fly but, among other things, much overweighted it and there were some evident foul-ups with the engine installation and such-like, all of which which resulted in the disappointing initial performance. Corrections of some of these details resulted in a, reportedly, much better performance in the second round of tests, even without a bigger engine. The contemporaneous 'estimations' of its future performance where not just based on upgrading the engine but also on a bunch of improvements to correct said foul-ups, reduce the overall weight and reduce drag.

It had very neat semi elliptical wing.

OTOH: Stuka was a hard hitter...and German numbers: https://www.youtube.com/watch?v=ZcyGOOReSgU

[gebhk]

Sadly, we don't actually know what its wing looked like.....

[Topspeed]

Sadly, we don't actually know what its wing looked like.....

On these lines seem that all are....about.

[gebhk]

Which are all best guesses of the various authors/artists. Alas, not the greatest substitute for actual knowledge.

[Topspeed]

Which are all best guesses of the various authors/artists. Alas, not the greatest substitute for actual knowledge.

That is correct...factory plans are missing.

pzl50-1.gif (28.38 KiB) Viewed 1148 times

[Von Schadewald]

Several years ago I presented this thread:

viewtopic.php?f=11&t=74286&p=669130&hilit=poles#p669130

31 August 1939: Poles preempt

Post by Von Schadewald » 28 Mar 2005 10:44

WI the Poles gain the full plans of "Case White", that the French and Rumanians aren't going to help them, and mobilise their entire 700,000 man army, destroyer flotilla, submarines, 300 fighters and 240 bombers and preempt the German attack with 1 day to spare?

The Germans are taken by surprise, with the Poles threatening for a short time Gorlitz and Cottbus, cavalry once again coming into its own. The Schleswig-Holstein is sunk, and a token bombing of Berlin is made. The Germans quickly take the counter-offensive, but a blitzkrieg advance is no longer possible, with heavy losses.

With irrefutable evidence of the hostile German intentions I think the Russians, French, Rumanians and British would now fall in with the Poles, a ceasefire is reached, and WWII is called off or delayed 5 years.

[gebhk]

Sorry, but this idea is utterly bonkers.

1) There would be no surprise. You cannot hide the preparations of an entire national armed forces to attack. At best you can sow the seeds of doubt, as the Allies did in 1944 pre-Normandy, as to the exact place of attack; and that in itself depends on whether you have the spare resorces to mount that sort of operation (and Poland did not) and that the enemy's spy network misses it. In any event there was little room for manoevre where choice of objectives went.
2) Polish logistics were even less able to sustain an army in the attack in a war of movement than they were in defence, particularly where the advance was in enemy territory. It is also patently clear that its capacity to carry out offensive operations against an enemy like the WH was subtantially less than the already limited capacity for defence.
3) All that would happen would be that the Polish armies would bloody and exhaust themselves attacking Germany and would then be even more vulnerable to being enveloped and destroyed than they were in the real 1939. In other words much the same would happen as IRL, just more quickly and decisively. Have a look at the map. If you have your head in a lion's mouth, shoving it further in is rarely the optimal plan!
4) No reason to imagine that the Soviets, Romanians, French, British and Slovaks would do anything different than they did in the real 1939, other than that it would have given the French and British the moral justification to not declare war. Given that both were desperately keen (among other things) not to offend US public opinion by appearing in any way the aggressors, this latter course I think likely.

[maltesefalcon]

IRL the Poles were caught flatfooted by the German invasion.

If it happened in this case, the Polish Air Force could be virtually destroyed on the ground in the initial attack; no matter what type of aircraft they had on inventory.

Bear in mind that the Luftwaffe successfully destroyed 2000 Soviet aircraft, on or about June 22/41.