Advanced French Fighters vs 1942/1943 contemporaries

[Shortround6]

Then what's left? One controversial achievement in the form of the AM-42? The major problems of the Soviet engine development were a severe lack of experienced engineers and the principle of "quantity over quality". Soviet engine designers were not willing to increase weight, but they were forced to do it because other solutions required too much time from the point of view of the Soviet leadership.

Right now I am looking at the M-100 through M-108 series to compare to the Parent Hispano engines. Not soviet engines in general, unless something pops out as being prevalent.
Other engines started out heavier than the H-S engines and some of them (most) increased weight.

In this reference book you will find a detailed description of the differences for each model from the previous one. Unfortunately I cannot attach the whole book - djvu-format is not allowed here, but I can post scans of the relevant pages if necessary.

I thank you for the effort but I cannot read Russian (or any other language) and while I can sometimes translate already translated Russian into something I can understand I may not get much out of some pages printed in Russian. My own failing.
Sometimes the English version of Kotelnikov's book needs a little more translating. I could be wrong but sometimes they used words like "ribbed" when an a western writer might have used the word "fins" when describing a cooling surface on an air cooled engine or the bottom of a piston. I can see how either translation could be correct from the original Russian but you sometimes have to guess at some of the wording/translation.
I can read the numbers and guess at the power ratings/altitudes but trying to sort out changes in crankshaft modifications might be a bit much.

I am going to try to list all the common V-12 engines from just under 34 liters to 36.7 liters to show how light the early Hispano and cousins were. And in the very early 30s and mid 30s there wasn't a good reason to build heavier engines. The problem came in when they tried to significantly increase the power.

 

[bf109xxl]

I cannot read Russian (or any other language) and while I can sometimes translate already translated Russian into something I can understand I may not get much out of some pages printed in Russian.

I can only suggest the use of OCR software (like the open source tesseract or commercial FineReader/OmniPage/Acrobat) followed by deepl translation. It is quite possible to get the essence.

Sometimes the English version of Kotelnikov's book needs a little more translating.

I have no right to criticize the translation of Kotelnikov or other authors, as my English is even worse, unfortunately. But I can understand the frustration of native speakers.

 

[bf109xxl]

Ok, I was probably too optimistic. I carried out an experiment using tesseract/deepl:

• cut out a rectangular fragment of the scanned page and saved it as a bitmap image (600dpi, BW)

• recognized the text using tesseract with default settings

>tesseract Fokin_example.png Fokin_example --dpi 600 -l rus

• cleaned up unnecessary hyphenation and paragraphs

• copied the result into the deepl input box and used Russian spell checker to eliminate errors that do not require knowledge of the Russian language and can be detected by character comparison only.

The final result was rather disappointing. But I am just curious whether this translation may be useful for a native speaker.

 

[TM06]

I think an important factor here for the French side is lack of adequate inline 12-cylinder engines to compete with the 12Z.
The Potez 8D was too small and underpowered, ditto with the Renault 12R. Renault had another 1,500~2,000 hp aircraft engine they were working on but I can't seem to scrounge up any information about it.
The only manufacturer to make engines with anything near the specs required were Lorraine-Dietrich with their 1,050 hp 12Q Eider and 1,200 hp 12R Sterna. Perhaps Lorraine could've reworked their 12Rcr Radium engine or made a derivative of it a la Rolls-Royce R. However the nationalization effectively killed the company and its engine prospects, leaving only Hispano-Suiza as the sole realistic prospect with no other engine programs to fall back on.
The 12Z was the engine France had to go with for the time being, so they'd have to bite the bullet and put it into production despite its flaws and problems.

 

[Shortround6]

The final result was rather disappointing

I am giving you a Bacon for the effort. You are going above and beyond. Thank you.

 

[Bretoal2]

I think an important factor here for the French side is lack of adequate inline 12-cylinder engines to compete with the 12Z.
The Potez 8D was too small and underpowered, ditto with the Renault 12R. Renault had another 1,500~2,000 hp aircraft engine they were working on but I can't seem to scrounge up any information about it.
The only manufacturer to make engines with anything near the specs required were Lorraine-Dietrich with their 1,050 hp 12Q Eider and 1,200 hp 12R Sterna. Perhaps Lorraine could've reworked their 12Rcr Radium engine or made a derivative of it a la Rolls-Royce R. However the nationalization effectively killed the company and its engine prospects, leaving only Hispano-Suiza as the sole realistic prospect with no other engine programs to fall back on.
The 12Z was the engine France had to go with for the time being, so they'd have to bite the bullet and put it into production despite its flaws and problems.

The Lorraine-Dietrich company was moribund well before the nationalizations. Becoming the SNCM (Société nationale de construction de moteurs) by the nationalization laws,, its engineers worked on a type 130/137 24-cylinder beast, aiming for 1600 to 1800 hp.

SNCM 130 and 137 24-Cylinder Aircraft Engines

The SNCM 130 was a hexagonal 24-cylinder aircraft engine designed in France just before WWII. A slightly smaller prototype version, the SNCM 137, was built and tested before the German invasion.

oldmachinepress.com

Unfortunately, this engine did not have time to be developed before June 1940, nor did the Mathis Vega.

 

[Shortround6]

I think an important factor here for the French side is lack of adequate inline 12-cylinder engines to compete with the 12Z.
The Potez 8D was too small and underpowered, ditto with the Renault 12R. Renault had another 1,500~2,000 hp aircraft engine they were working on but I can't seem to scrounge up any information about it.
The only manufacturer to make engines with anything near the specs required were Lorraine-Dietrich with their 1,050 hp 12Q Eider and 1,200 hp 12R Sterna. Perhaps Lorraine could've reworked their 12Rcr Radium engine or made a derivative of it a la Rolls-Royce R. However the nationalization effectively killed the company and its engine prospects, leaving only Hispano-Suiza as the sole realistic prospect with no other engine programs to fall back on.
The 12Z was the engine France had to go with for the time being, so they'd have to bite the bullet and put it into production despite its flaws and problems.

Well, the engine the French had to go with was the 12Y-50/51. And it was flawed, how badly is the question and how soon they could have straightened it out?
Now we get to the 12Z, and what is a reasonable expectation. 1300hp? 1400hp? a bit more? The 1600hp is rather doubtful.

You can build a reasonable fighter using a 1300-1400hp engine in 1942/43. It won't be great, but reasonable. Soviets had to use wood construction which was heavy but they they had light, fast firing guns which helped. Now do the French stay close to the border or do they want to play long range bomber game.
I picked Troyes as a start point, a bit over 100 miles south of the Belgium/Luxemburg border and 150 miles from Saarbrucken (how close should the French bomber fields be to the "front".)
distances from google maps are
Munich 345 miles
Nuremberg 330 miles
Dresden 470 miles
Berlin 500 miles
Hamburg 475 miles

Do the French embrace the fighter/bomber concept or not? Using 150 sq ft and smaller wings makes things difficult.

By the time the Yak-3 was actually put in production the Soviets had the Yak-9 and La-5 to handle some the duties the Yak-3 could not do which freed up the Yak-3 to play close range air superiority fighter.

Granted the French do NOT have to stick with one or two designs. But they are stuck with the Hispano engine for many of them.

 

[tomo pauk]

Well, the engine the French had to go with was the 12Y-50/51. And it was flawed, how badly is the question and how soon they could have straightened it out?
Now we get to the 12Z, and what is a reasonable expectation. 1300hp? 1400hp? a bit more? The 1600hp is rather doubtful.

You can build a reasonable fighter using a 1300-1400hp engine in 1942/43. It won't be great, but reasonable.

I's say that the 12Y-51 is perhaps the most secure bet for the French for the late 1940 and the good part of 1941. If/once it is outfitted with the S-P S/C and with 100 oct fuel, it might be in between the DB 601A and 601N? With the French fighters being small, we can expect about 600 km/h at 4000-5000m? Competitive for the time before the second half of 1941 by all means.

1300-1400 HP on a HS 12 engine with S-P supercharger, like the early 12Z, means that it does that power also at 5-6 km (no ram). Or, as good as the best German engines of 1941-43. Or notably better than the Merlin 20 series. Thus one can have a very, very competitive fighter built around it, sorta the MC.205 or Re.2005, but many months earlier. Such a V12 was a wet dream for the Italians, Japanese, Klimov, and the Allison company before the 2-stage V-1710 was introduced (I'll disregard the turboed V-1710).

Do the French embrace the fighter/bomber concept or not? Using 150 sq ft and smaller wings makes things difficult.

By the time the Yak-3 was actually put in production the Soviets had the Yak-9 and La-5 to handle some the duties the Yak-3 could not do which freed up the Yak-3 to play close range air superiority fighter.

Same for the French if they survive, with HS-powered fighters flying support to the G&R-powered fighter-bombers. Plus the P-40s.

 

[TM06]

Do the French embrace the fighter/bomber concept or not? Using 150 sq ft and smaller wings makes things difficult.

I don't believe they would, at least not for single-engined fighters. None of the main single-engined fighters (M.S.406, D.520, VG.33, M.B.152) could carry bombs or rockets, and the only one that would be feasible to do so would be the Bloch's with their thicker wings and more immediately powerful radial engines.
However, France had many twin-engined aircraft that could pick up that slack, such as the NC.600, Br.700, Potez 670 and (potentially) CAPRA R.40.
The older Potez 630, MB.17x and especially the Br.693 were quite capable in this role, so what where effectively better versions of said aircraft would likely be strong players.
There's also the Loire-Nieuport LN.40 series, with the LN.42 being a strong potential dive bomber.

Granted the French do NOT have to stick with one or two designs. But they are stuck with the Hispano engine for many of them.

This was kind of the point I was getting at. France is more-or-less stuck with the 12Y and 12Z for better and worse, gritting through their flaws until they can fix them. At least they have a very competent radial engine manufacturer in Gnome et Rhône, which could probably get a lot more out of the 14N and 14R.

 

[Bretoal2]

This was kind of the point I was getting at. France is more-or-less stuck with the 12Y and 12Z for better and worse, gritting through their flaws until they can fix them. At least they have a very competent radial engine manufacturer in Gnome et Rhône, which could probably get a lot more out of the 14N and 14R.

No.

In 1940 the G&R 14 N, in its latest versions 38/39 and 48/49, reached its peak power owing to the lack of a 2-speed supercharger and absence of a central crankshaft bearing.

After the war, SNECMA (nationalized G&R) had to make hundreds of modifications to the 14 N to improve its reliability, but the engine was then approved at powers identical to, or even lower than, those of 1938 (G&R 14 N 64/65) !

In fact, 14 N + 2 speed supercharger + crankshaft center bearing = G&R 14R.

Engineer Albert Caquot's dream was to see a 14R come out with a Szydlowski supercharger ...

 

[Shortround6]

I's say that the 12Y-51 is perhaps the most secure bet for the French for the late 1940 and the good part of 1941. If/once it is outfitted with the S-P S/C and with 100 oct fuel, it might be in between the DB 601A and 601N?

The Swiss didn't get it sorted out until late 1943 or early 1944. Lost a few engines due to crankshaft failures (lubrification?). Maybe the French could sort it out earlier.
You can put 100 octane in an H-S engine, it will run, the question is what do you get out of it. None of the H-S engines and cousins seem to have run at over 8.6lbs/1200mm pressure even in the late 40s. Granted some people did not use WER when there was no war. The H-S engines were weak mechanically(weak crankcase, weak crankshaft, weak rods?) and had cooling problems. Maybe the radiators were too small? Maybe you could drop the compression a little but 100 octane was never going to allow 12-15lbs of boost.

1300-1400 HP on a HS 12 engine with S-P supercharger, like the early 12Z, means that it does that power also at 5-6 km (no ram). Or, as good as the best German engines of 1941-43. Or notably better than the Merlin 20 series.

We have a lack of data. Don't know what the 1300hp and 1400hp versions were using for boost. They may have been running at 2600rpm. Now one would hope that a 36 liter engine could make more power than a 27 liter engine. What we don't know is if it met the goals and if you needed 3 engines to keep the plane in the air as long as one Merlin 20 would before overhaul.

Same for the French if they survive, with HS-powered fighters flying support to the G&R-powered fighter-bombers. Plus the P-40s.

The US a British tended to use one airframe for different roles, even if the squadrons specialized. The Soviets did use at least 50kg bombs under some of the Laggs and Yaks. Maybe not common but they had the option.
109s started playing fighter bomber in the BoB.
Maybe the French get P-40Ds instead, in addition to, the British?

 

[tomo pauk]

Engineer Albert Caquot's dream was to see a 14R come out with a Szydlowski supercharger ...

Supercharger on the 14R was already very good, if not excellent already. It was better than what BMW used on the 801C and D, or what Bristol used on Hercules.
What was not excellent was timing of the 14R.

 

[tomo pauk]

You can put 100 octane in an H-S engine, it will run, the question is what do you get out of it. None of the H-S engines and cousins seem to have run at over 8.6lbs/1200mm pressure even in the late 40s. Granted some people did not use WER when there was no war. The H-S engines were weak mechanically(weak crankcase, weak crankshaft, weak rods?) and had cooling problems. Maybe the radiators were too small? Maybe you could drop the compression a little but 100 octane was never going to allow 12-15lbs of boost.

I don't have such the great expectations either, for any service-worthy. Might get perhaps 50-100 HP extra with a tad of added boost?

We have a lack of data. Don't know what the 1300hp and 1400hp versions were using for boost. They may have been running at 2600rpm. Now one would hope that a 36 liter engine could make more power than a 27 liter engine. What we don't know is if it met the goals and if you needed 3 engines to keep the plane in the air as long as one Merlin 20 would before overhaul.

The earliest 12Z, called 12Y-89 in 1939, seems to be using 2600 rpm and 850 mm Hg, with 2800 as over-speed? Like 3150 rpm limit on the Merlin for dive?
Supposedly good for 1500 mm Hg in overboost - that is probably a typo, the 1050 mm Hg as a true value? Note that engine gained a lot of weight (finally, I'd say), at 640 kg - almost 30% heavier than the 12Ys the French pilots took in the combat in 1940. Pretty high altitudes were hoped for, with the rated altitude supposed to be over 7000m.
FWIW

Meeting of the goals should've been probably easier to do with the specified time frame for this thread (1942-43), or even for 1941, then for 1940.

The US a British tended to use one airframe for different roles, even if the squadrons specialized. The Soviets did use at least 50kg bombs under some of the Laggs and Yaks. Maybe not common but they had the option.
109s started playing fighter bomber in the BoB.
Maybe the French get P-40Ds instead, in addition to, the British?

Be it as it might, IMO the 1st role the French fighters, and their crews and commanders had to do, is fending off the LW in the skies.

 

[Bretoal2]

Power curves and boosts of post-war 12Z (12 Z-17) are in this thread :

HS.12Z-17 Engine

It was used on the Yugoslav S-49C fighters and I literally cannot find any information regarding the power curve of the engine. What it’s nominal power was at Sea Level, what the power was at over post at Sea level and the critical alt power. All I can find it that the engine is rated 1480...

ww2aircraft.net

 

[Shortround6]

I don't believe they would, at least not for single-engined fighters. None of the main single-engined fighters (M.S.406, D.520, VG.33, M.B.152) could carry bombs or rockets, and the only one that would be feasible to do so would be the Bloch's with their thicker wings and more immediately powerful radial engines.

Thickness of the wings has nothing to do with it. If the wing is strong enough to handle a plus 6 G turn as a fighter it is strong enough to lift and bomb and drop it unless you do something really stupid, like dive at 80 degrees and try to pull out at high speed. Radial engines later.

However, France had many twin-engined aircraft that could pick up that slack, such as the NC.600, Br.700, Potez 670 and (potentially) CAPRA R.40.

Not really.

The older Potez 630, MB.17x and especially the Br.693 were quite capable in this role, so what where effectively better versions of said aircraft would likely be strong players.

again, not really.
Many of your selections use the G-R 14M engine. About 700hp which means you are buying a twin engine aircraft to do the job a single engine plane could do, assuming you had a decent single engine to choose from. A few of them tried to use P&W R-1535s as the closest match but the P&W was larger (more drag) and heavier. A few tried to use a small 14 Cylinder Hispano radial but that engine was notoriously unreliable even in comparison to the G-R 14M which is really saying something.

The Problem with this group of aircraft is that by the time you stuff bigger engines into them and fit bigger wings and tails and fuselages you have new airplanes.

Compare most of them to a Bf 110C and see how good they really look.

There's also the Loire-Nieuport LN.40 series, with the LN.42 being a strong potential dive bomber.

Or not. The Loire-Nieuport LN. 40 series was roughly equal to the Ju-87A with a Jumo 210 engine except the LN.40s didn't have a rear gunner. But in Sept 1939 the Germans had over 300 Ju-87Bs with Jumo 211 engines, and we are back to "potential". One prototype LN.42 that barely had any flight time.

At least they have a very competent radial engine manufacturer in Gnome et Rhône, which could probably get a lot more out of the 14N and 14R.

And we have a debatable point here also
You are not going to get much more out of the 14N engine.
Russians built it as the M-88. They added over 100lbs and a 2 speed gear box for the supercharger.
You can also look at the Piaggio P.XIX
The 14N had hit a brick wall. The only way through, over, around it was the 14R with the 3rd bearing on the crankshaft. (and a lot more cooling fins).
But that means that all you saved from the 14N was the bore and stroke. Just about everything else has to be changed. Even if it works, that takes time.

 

[Shortround6]

The earliest 12Z, called 12Y-89 in 1939, seems to be using 2600 rpm and 850 mm Hg, with 2800 as over-speed? Like 3150 rpm limit on the Merlin for dive?

I believe you are right. Post war they were advertising 2800rpm for the power ratings, both take-off and altitude.

 

[TM06]

Thickness of the wings has nothing to do with it. If the wing is strong enough to handle a plus 6 G turn as a fighter it is strong enough to lift and bomb and drop it unless you do something really stupid, like dive at 80 degrees and try to pull out at high speed. Radial engines later.

I was always under the impression that a plane's ability to carry under-wing bombs was determined by wing thickness, wing strength and horsepower. If not, guess I got plenty more to learn.

again, not really.
Many of your selections use the G-R 14M engine. About 700hp which means you are buying a twin engine aircraft to do the job a single engine plane could do, assuming you had a decent single engine to choose from. A few of them tried to use P&W R-1535s as the closest match but the P&W was larger (more drag) and heavier. A few tried to use a small 14 Cylinder Hispano radial but that engine was notoriously unreliable even in comparison to the G-R 14M which is really saying something.

The Problem with this group of aircraft is that by the time you stuff bigger engines into them and fit bigger wings and tails and fuselages you have new airplanes.

Compare most of them to a Bf 110C and see how good they really look.

The NC.600 and Potez 670 yes, however the Br.700 (and the 697) and the MB.17x all used the 14N, with the R.40 using 12Y engines and the R.41 using 12Z engines. Cross-examining their performance with the Bf 110 C's performance shows quite solid results on the French side.
The NC.600 and Potez 670 (+671) were slower but climbed better while being lighter.
The MB.175 was roughly the same in terms of performance but lacked a strong forward armament - something that could be fixed relatively easily.
The Br.697 almost entirely outclasses it with heavier armament, higher top speed and better climb rate, and the Br.700 was expected to be even faster and climb better.
The CAPRA R.40 and R.41 are easily the most standout of these choices, with much higher projected top speeds and climb rates along with strong armaments.

And we have a debatable point here also
You are not going to get much more out of the 14N engine.
Russians built it as the M-88. They added over 100lbs and a 2 speed gear box for the supercharger.
You can also look at the Piaggio P.XIX
The 14N had hit a brick wall. The only way through, over, around it was the 14R with the 3rd bearing on the crankshaft. (and a lot more cooling fins).
But that means that all you saved from the 14N was the bore and stroke. Just about everything else has to be changed. Even if it works, that takes time.

So the 14N was incapable of being developed further, got it.
Given that the 14R had almost the same displacement, length and width, would it be possible to sort of "drag and drop" it into planes that previously fit the 14N? Minor modifications withstanding of course.

 

[Bretoal2]

Henri Déplante, who drawn the Bloch 152 / 155, writes that the plane was not suitable for a more powerful engine. The Bloch 157 was an entirely new design.

The G&R 14R was much heavier than 14N and had to drive a larger propeller to withstand the extra power.

 

[TM06]

Henri Déplante, who drawn the Bloch 152 / 155, writes that the plane was not suitable for a more powerful engine. The Bloch 157 was an entirely new design.

The G&R 14R was much heavier than 14N and had to drive a larger propeller to withstand the extra power.

So that'd be a "no" on the easy installation then. Unfortunate, I'd love to see what something like the SE.100 could do with the extra power.

 

[Shortround6]

So that'd be a "no" on the easy installation then. Unfortunate, I'd love to see what something like the SE.100 could do with the extra power.

Heck, I would like to see a squadron of Se.100s landing on a rough airfield
Take bets on how many survive.