Advanced French Fighters vs 1942/1943 contemporaries

[TM06]

France is a nation that gets swept under the rug when discussing aircraft of WW2, but when looking upon what they had planned, they had a number of strong contenders that likely would have been produced if not for the Fall or if Germany didn't place the embargo on them. Specifically - and the primary aircraft referred to in this discussion - the Dewoitine D.520Z/SE.520Z, Dewoitine D.551, Arsenal VG.39Bis, Bloch M.B.157 and Arsenal VB 10.
These 5 planes were planned to be produced around 1942~1943, meaning their competition would be as such:
Germany: Bf 109 F-4, G-2 and G-6 / Fw 190 A-4 and A-5.
Britain: Spitfire Mk IX, LF Mk IX, XVII and XIV / Hawker Typhoon.
Russia: La-5 and La-5FN / Yak-1, Yak-7B, Yak-9 and Yak-9T.
USA: P-40F and P-40N / P-51B and P-51C / P-47C and P-47D / F4U-1 and F4U-1C / F6F-3 and F6F-5.
Italy: C.202EC, C.205 Serie III and C.205N2 / G.55 / Re.2001 and Re.2005.
Japan: A6M5 / Ki-44 / Ki-61-I and Ki-61-II / N1K1-J and N1K2-J.
So my question to you fine folks is this:
How would these fearsome French fighters fare facing the fierce foes of the early forties?

 

[Frog]

I think one of their main trouble would have been a reliable and powerful enough engine.

 

[TM06]

I think one of their main trouble would have been a reliable and powerful enough engine.

Unreliable? Yes. Not powerful enough? Definitely not.
The 12Z engine was quite powerful for its time, being a bit behind the Merlin and well ahead of the DB 601A.
I've also admittedly not heard much about the 157's 14R beyond its power and capabilities, so I can't speak further about that one's reliability.

 

[SaparotRob]

I believe S Shortround6 posted an excellent graphic on the capabilities of these aircraft recently.

 

[Shortround6]

The 12Z engine was quite powerful for its time, being a bit behind the Merlin and well ahead of the DB 601A.

Depends on which Merlin. while ahead of the DB601A looks good at first glance, the Germans were sticking DB601 engines in 109s/110s in late summer and early fall of 1940.
The 12Z has a lot claims, reality may have been different. Figures from Wiki are from the 1946 edition of Aircraft Engines of the World 1946. and require 100-130 fuel, a two speed supercharger and a direct fuel injection system and a lot of faith. Work on the type 89 12Z started in Barcelona in 1942.
Earlier work in France seems to have peaked at 1400hp using 2600rpm and carburetors.
The Swiss had a lot of trouble with their production of H-S engines during and after WW II which cast a lot of doubt about the actually suitability of the 1940 H-S engines.

I've also admittedly not heard much about the 157's 14R beyond its power and capabilities, so I can't speak further about that one's reliability.

This is about as close to vaporware as you can get and actually have pictures. What you actually have is a handful of engines that actually flew in WW II (with a finger or two left over)
and little or no sales after the war. With fantastic claims for performance.
In 1946 it was claiming 1525hp at 2600rpm at 20,000ft from 2360cu in. 2 speed supercharger. 1805lb engine
P&W was claiming 1700hp at 2800rom at 16,000ft from their R-2800 CA 15 engine with two speed supercharger, 2360lb engine.
P&W should have locked their doors and gone home if the French claims were true.

SNECMA 14R - Wikipedia

en.wikipedia.org

There are several false claims in here, like " an increase in cylinder capacity," which is very hard to do if you don't change either the bore or the stroke (or add cylinders).
They kept the same cylinder dimensions as the every other G-R 14 cylinder radial engine which were also the same as the Hercules engines.

 

[tomo pauk]

Figures from Wiki are from the 1946 edition of Aircraft Engines of the World 1946. and require 100-130 fuel, a two speed supercharger and a direct fuel injection system and a lot of faith.

There are several false claims in here, like " an increase in cylinder capacity," which is very hard to do if you don't change either the bore or the stroke (or add cylinders).

I think that were beyond the point of trusting Wilkinson's numbers as gospel for many not-so-well documented engines (like the wartime French types, or the Sabre 7). Sales brochures as source for him?
At least the users of this forum have an access to the numbers that can be considered as real.

My take on the newest and bestest French fighters - a HS 12Z with 1400-1500 HP at altitude (~5.8 km?) puts them in very good position for 1941-43. So does the G&R 14R, that was making the power in-between the BMW 801C and fully-rated 801D. French fighters were of small size, and Germany was just across the Rhine basically, so the fighters can do a lot of good work if France is still in the fray.

French have just a minor favor to ask - that Germans don't crush them in 1940, and I'm afraid that is asking a lot.

I've also admittedly not heard much about the 157's 14R beyond its power and capabilities, so I can't speak further about that one's reliability.

What data you have on the 14R? Anything resembling a primary source hopefully?

 

[TM06]

What data you have on the 14R? Anything resembling a primary source hopefully?

Unfortunately no, I'm relatively new around here and haven't delved too deep into radial engines. Most of my "knowledge" about the 14R comes from scattered bits and pieces around the M.B.157 so I cannot in good faith say I have any authority to make claims about it.

 

[Shortround6]

My take on the newest and bestest French fighters - a HS 12Z with 1400-1500 HP at altitude (~5.8 km?) puts them in very good position for 1941-43. So does the G&R 14R, that was making the power in-between the BMW 801C and fully-rated 801D. French fighters were of small size, and Germany was just across the Rhine basically, so the fighters can do a lot of good work if France is still in the fray.

French have just a minor favor to ask - that Germans don't crush them in 1940, and I'm afraid that is asking a lot.

The French in 1940-41 (assuming they survive) have a number of problems. While work started on the 12Z in 1938 it was still very much a prototype engine in the Spring of 1940.
The Hispano book is help but sometimes leaves out altitude. There was also the practice of some authors of quoting "equivalent ground power" Power the engine could make in theory if the engine could be run at wide open throttle at sea level with fuel that would not detonate. The 12Y-51 was rated at 1500hp that way. Reality with existing fuel was 1000hp at 3260 meters and 1100hp for take-off.
You can't make 12Z engines using 12Y machinery in the factories. Or at least you can't make many of the parts. Changing from 2 valve SOHC heads to 4 valve DOHC heads requires new castings and a lot of new tooling. New crankshaft and new connecting rods. Maybe you can use the old machinery to work on the blocks?
The 12Z used in the VG 33 prototype made 1200hp at 2600rpm, altitude not specified, using carburetors. There was a 1300hp version, the 12-Z Ter installed in the D-524 but with the armistice, never flown.
There were 12Z engines fitted with H-S superchargers and 12Zs with Szydlowski superchargers. There were also 12Ys fitted with both. During the war in Spain there were also two speed superchargers tested. Power ratings are all over the place. I would note that in Spain the engines were tested for duration in a 50 hour test in Aug 1943.

As noted in earlier threads, the Soviet M-105 and the Swiss Saurer YS-2 were improved versions of the basic H-S 12Y engines somewhat comparable to the 12Z. Neither got 100 octane fuel and neither got anywhere near the claimed power out put of 12Z.

The G-R 14R is in a similar situation only worse. You need new tooling for one thing. One flying sample of the engine disappears into Germany, next engines show up in late 1944?
four more engines are flown in 1948?
Basically you have a poppet valve Hercules that runs 200rpm slower. It is about 190lbs lighter.

 

[tomo pauk]

You can't make 12Z engines using 12Y machinery in the factories. Or at least you can't make many of the parts. Changing from 2 valve SOHC heads to 4 valve DOHC heads requires new castings and a lot of new tooling. New crankshaft and new connecting rods. Maybe you can use the old machinery to work on the blocks?

The G-R 14R is in a similar situation only worse. You need new tooling for one thing.

It is not like we're trying to tool-up the car factories to make aero engines.
Yes, so many months will be needed to change the part of tooling, similar as it was needed for the factories making the switch between DB 601 and 605, or these making a switch from Jumo 210 to 211 (and later the 211 into 213).

One flying sample of the engine disappears into Germany, next engines show up in late 1944?
four more engines are flown in 1948?

Country being conquered can have it's downsides.

As noted in earlier threads, the Soviet M-105 and the Swiss Saurer YS-2 were improved versions of the basic H-S 12Y engines somewhat comparable to the 12Z. Neither got 100 octane fuel and neither got anywhere near the claimed power out put of 12Z.

Soviets did got the 95 oct fuel. Saurer certainly did received hi-oct fuel after 1944?
I don't think that M-105 was comparable to the 12Z, it was barely better than the 12-51. The M-107 was probably the equivalent.

Basically you have a poppet valve Hercules that runs 200rpm slower. It is about 190lbs lighter.

It also has a better S/C.

 

[Admiral Beez]

I think one of their main trouble would have been a reliable and powerful enough engine.

The Arsenal VG-40 and Dewoitine D.521 with their intended Rolls-Royce Merlin engines would have addressed such issues.

Or, if produced in Vichy France, perhaps the DB 605 could be used, making a French equal to the Fiat G.55, Macchi C.205 or Reggiane Re.2005.

 

[Shortround6]

It is not like we're trying to tool-up the car factories to make aero engines.
Yes, so many months will be needed to change the part of tooling, similar as it was needed for the factories making the switch between DB 601 and 605, or these making a switch from Jumo 210 to 211 (and later the 211 into 213).

Wright and P&W also significantly re-tooled for some of the R-1820, R-1830, R-2600 and R-2800 engines.
But it takes months. Lots of months. In 1940-41 France is stuck with the 12Y-51 at best and it may have had problems?

Country being conquered can have it's downsides.

Very true, but in 1947-48 when the last 14R engines showed up (my mistake, eight engines and spares?)

There were proposals to use Bristol Hercules 730 (licensed by SNECMA, same company) and Jumo 213s being built in France.
By this time the Hercules was into the 230/630/730 series engines which, like many radial engines, pretty much kept the bore and stroke of the earlier engines and very little else.

Soviets did got the 95 oct fuel. Saurer certainly did received hi-oct fuel after 1944?
I don't think that M-105 was comparable to the 12Z, it was barely better than the 12-51. The M-107 was probably the equivalent.

Saurer is supposed to have 93 octane for the YS-2. Late 40s used 91/98 octane?
Post war they built the YS-3 (single speed supercharger) and YS-4 which had a variable speed drive on the supercharger. Used 100/130 but that was the standard grade above 91-98 at the time.
What is kind of interesting is comparing the different Hispanos and kin (cousins?) to the DB-601/605 and the Jumo 211/213.

The M-105 is sort of an in-between engine. It had 3 valves per cylinder while the French, Spanish and Swiss engines had either 2 or 4. M-105 also had two speed supercharger which was a rarity on the non Soviet Hispanos. Yes the soviets had to wait for the V-107 to get 4 valve heads and DOHC.
RPM limits on these engines was all over the place. 12Y-51 was 2500rpm. The YS-2 was 2600rpm (?) the YS-3 and YS-4 was 2800rpm. The 12Z changed from 2600rpm on early versions to 2800rpm. M-105 started at 2600rpm (?) and raised to 2700rpm and perhaps even 2800rpm?

 

[Bretoal2]

About Saurer : above all, they had carried out a massive redesign of the original 12 Y crankshaft, whose weight had virtually doubled.

And for Klimov.... The VK 107 was a "copy" of the 12Z principle : dual inlet, with differential opening diagram, one valve with carbureted air and one valve with pure fresh air. We have already had some discussion about these two strange engines.

The VK 107 was supposed to give more than 1600 hp, but with a very objectionnable fiability. The 12 Z never ran satisfactorily (see tremendous exhaust smoke traces on BV 10 fuselage...) and was supplanted by the Hispano 12 B - designed by ing. Jacques Blanc, who had drawn before war... the G&R 14 R !

And just to set the chronology clearly: patents for the "differential" diagrams of the 12Z (by Louis Birkigt) are in 1937 and 1938.

 

[Bretoal2]

The G-R 14R is in a similar situation only worse. You need new tooling for one thing. One flying sample of the engine disappears into Germany, next engines show up in late 1944?

No. The 14 R was the development of the 14 P, which itself was the development of the 14 N. Certainly not a "new" engine.

The 14 R was presented at the Paris aero show in December 1938 under the misleading name 14 N-50 "dont les essais encore secrets se poursuivent". But the pictures clearly show that this engine is no longer a 14N...: bigger main casing (to accommodate the crankshaft central bearing), much increased finning, 7-ducts supercharger outlet, etc. And performances showing a two-speed supercharger.

The Loire-Nieuport 10 flew at the end of 1939 with type-tested 14 R (14 R 2/3), and a few weeks later so was the LeO 455. In fact, it was the (Italian-German) armistice commission who banned tests of these aircraft to resume after armistice, such as those of the Amiot 358 with 12Z engines.

 

[TM06]

Wright and P&W also significantly re-tooled for some of the R-1820, R-1830, R-2600 and R-2800 engines.
But it takes months. Lots of months. In 1940-41 France is stuck with the 12Y-51 at best and it may have had problems?

If the 12Y-51 is the best they have, then I might be able to add another plane to this list of potential main fighters: The D.551.
As opposed to the SE.520Z which was an overhaul of the existing D.520's frame using the 12Z, the D.551 was an almost completely different aircraft using the 12Y-51 (Although the D.554 model was slated to use the 12Z). It had excellent performance even when armed, in Danel and Cuny's books about the D.520 they claim a top speed of ~660 km/h at 4,000 meters.
Given how they had a few prototypes already made and orders by the French air force, it's likely they would've come online around this same time frame.

 

[tomo pauk]

But it takes months. Lots of months. In 1940-41 France is stuck with the 12Y-51 at best and it may have had problems?

Many months = less than a year? Note that this thread is about 1942-43.

Very true, but in 1947-48 when the last 14R engines showed up (my mistake, eight engines and spares?)
There were proposals to use Bristol Hercules 730 (licensed by SNECMA, same company) and Jumo 213s being built in France.
By this time the Hercules was into the 230/630/730 series engines which, like many radial engines, pretty much kept the bore and stroke of the earlier engines and very little else.

1947-48 is 7-8 years after France was occupied. 3-4 years of occupation will play havoc with domestic engine development.

The M-105 is sort of an in-between engine. It had 3 valves per cylinder while the French, Spanish and Swiss engines had either 2 or 4. M-105 also had two speed supercharger which was a rarity on the non Soviet Hispanos. Yes the soviets had to wait for the V-107 to get 4 valve heads and DOHC.

The 2-speed S/C on the M-105 is kinda/sorta a replacement for the variable S/C inlets, the thing that French were introducing on HS 12s by 1939.

RPM limits on these engines was all over the place. 12Y-51 was 2500rpm. The YS-2 was 2600rpm (?) the YS-3 and YS-4 was 2800rpm. The 12Z changed from 2600rpm on early versions to 2800rpm. M-105 started at 2600rpm (?) and raised to 2700rpm and perhaps even 2800rpm?

2600 rpm for the M105, although the German docs say 2700 rpm.
The VK-105PF2 went to 2700 rpm, while also making a much greater boost (it was also a much heavier engine than the M-105).

As opposed to the SE.520Z which was an overhaul of the existing D.520's frame using the 12Z, the D.551 was an almost completely different aircraft using the 12Y-51 (Although the D.554 model was slated to use the 12Z). It had excellent performance even when armed, in Danel and Cuny's books about the D.520 they claim a top speed of ~660 km/h at 4,000 meters.

The D.551 was even smaller than the small D.520, and with lower weight - size matters, and same for the weight. Especially if one has lower-powered engines than the opponent.

 

[TM06]

The 12 Z never ran satisfactorily (see tremendous exhaust smoke traces on BV 10 fuselage...) and was supplanted by the Hispano 12 B - designed by ing. Jacques Blanc, who had drawn before war... the G&R 14 R !

Do you have any information about this 12B engine? I can't seem to find anything online about it other than that it existed.

 

[bf109xxl]

2600 rpm for the M105, although the German docs say 2700 rpm.
The VK-105PF2 went to 2700 rpm, while also making a much greater boost (it was also a much heavier engine than the M-105).

Already M-105P/PF operated at 2700 rpm at higher altitudes - I can post scans (in Russian) if necessary. M-105PF2 was not _much_ heavier - the difference between 105PA/PF/PF2 was rather negligible (600-620 kg, the PA could be converted into the PF during repair). Indeed, only the M-107A was significantly heavier.

 

[tomo pauk]

Already M-105P/PF operated at 2700 rpm at higher altitudes - I can post scans (in Russian) if necessary. M-105PF2 was not _much_ heavier - the difference between 105PA/PF/PF2 was rather negligible (600-620 kg, the PA could be converted into the PF during repair). Indeed, only the M-107A was significantly heavier.

Indeed, I've chaecked out the weight fgures, seems like the earliest M-105s were at 570 kg.
Any original docs are welcomed here.

 

[bf109xxl]

Indeed, I've chaecked out the weight fgures, seems like the earliest M-105s were at 570 kg.
Any original docs are welcomed here.

Early M-105 - 570-580, PF - 600/620 (according to different sources), PF2 had only minor differences from PF - the weight in principle could not change appreciably..

 

[bf109xxl]

Any original docs are welcomed here.