Advanced French Fighters vs 1942/1943 contemporaries

[TM06]

There was zero chance of the HS 12B showing up in WW II.

Forget the 12B, that is a unicorn.
The whole H-S engine is problem, H-S was promising more power from less weight than anybody else. And the two other Hispano derived families (Swiss and Soviet) never came close to the power/weight ratio that H-S trying for. And they both had trouble with reliability/durability.

Why? If Hispano recognize the fundamental flaws with the 12Z engine - which they almost certainly would by around 1941 - then their attempts to fix it would likely result in the 12B or something similar. Looking at the images provided earlier in the thread paints it as just a solid engine rather than anything groundbreaking. The specs of the engine also place it quite squarely within the late-war inline V12's (DB 603, Jumo 213, Griffon VI / 61 / 65, Merlin 66, VK-107, AM-42, certain V-1710's) without being ridiculous. Given that the engine started development in 1945 and was ready for production in 1948, it being developed in 1941 would result in it being ready for production in 1944 - which also lines up with the previously mentioned V12's.

 

[Shortround6]

There is a real problem or rather a host of them trying to compare post WW II engine development to 1940-43 engine development.
For everything that makes development easier there is something that makes it harder. A 1945 design team has most of the knowledge that several other design teams spent 4-5 years acquiring. A lot of that covers materials and manufacturing techniques and processes. But the budgets and manpower are lower. In war time there are external constraints, like access to machine tools and materials regardless of cost/funding.

And an awful lot does depend on funding.

There seem to be two 12B power plants if not Three. There was a design study of a 12 -Z-B conducted in Barcelona which may have been the first. Double compressor with intercooler.
The French version/s of the 12B seems to have rivaled the Napier Nomad for complexity. Finding information on the "bare" engine is difficult and the ultimate version for power at 10,000 meters wound up with a 2190kg power plant. However that included the exhaust driven turbine/s that powered not only the 1st stage of the supercharger but also the 'fan' that provided the air flow through the radiators and then this air from the radiators was blended into mix of the exhaust gases (turbo waste gates?) the radiator air, and main exhaust from the turbo unit. Main exhaust and 2 concentric rings (?) around the main turbo exhaust nozzle. I have no idea how they handled the intercooler (liquid cooling tied to the radiators?)
Date of this contraption is a little iffy. 5 prototypes were built, it was never flown. Some information was published in the 1950 and 1951 editions of Jane's for basic engine but it was never marketed. The 12-B engine is supposed to have received it's approval tests in 1951 as a simple engine and the 1951/52 Jane's says the integral propulsion version was "under development"
This is from pages 368-370 of Hispano Suiza in Aeronautics by Manuel Lage.

I have no idea what was supposed to be ready for production in 1948.

 

[Bretoal2]

There is a real problem or rather a host of them trying to compare post WW II engine development to 1940-43 engine development.
For everything that makes development easier there is something that makes it harder. A 1945 design team has most of the knowledge that several other design teams spent 4-5 years acquiring. A lot of that covers materials and manufacturing techniques and processes. But the budgets and manpower are lower. In war time there are external constraints, like access to machine tools and materials regardless of cost/funding.

And an awful lot does depend on funding.

There seem to be two 12B power plants if not Three. There was a design study of a 12 -Z-B conducted in Barcelona which may have been the first. Double compressor with intercooler.
The French version/s of the 12B seems to have rivaled the Napier Nomad for complexity. Finding information on the "bare" engine is difficult and the ultimate version for power at 10,000 meters wound up with a 2190kg power plant. However that included the exhaust driven turbine/s that powered not only the 1st stage of the supercharger but also the 'fan' that provided the air flow through the radiators and then this air from the radiators was blended into mix of the exhaust gases (turbo waste gates?) the radiator air, and main exhaust from the turbo unit. Main exhaust and 2 concentric rings (?) around the main turbo exhaust nozzle. I have no idea how they handled the intercooler (liquid cooling tied to the radiators?)
Date of this contraption is a little iffy. 5 prototypes were built, it was never flown. Some information was published in the 1950 and 1951 editions of Jane's for basic engine but it was never marketed. The 12-B engine is supposed to have received it's approval tests in 1951 as a simple engine and the 1951/52 Jane's says the integral propulsion version was "under development"
This is from pages 368-370 of Hispano Suiza in Aeronautics by Manuel Lage.

I have no idea what was supposed to be ready for production in 1948.

The Hispano-Suiza 12B was designed by Jacques Blanc, former chief engineer of Gnome-Rhône who took refuge in the unoccupied zone, while the management of G&R remained in Paris.

Conclusion: no French collapse in 1940 = no Hispano 12B.

 

[TM06]

There is a real problem or rather a host of them trying to compare post WW II engine development to 1940-43 engine development.
For everything that makes development easier there is something that makes it harder. A 1945 design team has most of the knowledge that several other design teams spent 4-5 years acquiring. A lot of that covers materials and manufacturing techniques and processes. But the budgets and manpower are lower. In war time there are external constraints, like access to machine tools and materials regardless of cost/funding.

And an awful lot does depend on funding.

There seem to be two 12B power plants if not Three. There was a design study of a 12 -Z-B conducted in Barcelona which may have been the first. Double compressor with intercooler.
The French version/s of the 12B seems to have rivaled the Napier Nomad for complexity. Finding information on the "bare" engine is difficult and the ultimate version for power at 10,000 meters wound up with a 2190kg power plant. However that included the exhaust driven turbine/s that powered not only the 1st stage of the supercharger but also the 'fan' that provided the air flow through the radiators and then this air from the radiators was blended into mix of the exhaust gases (turbo waste gates?) the radiator air, and main exhaust from the turbo unit. Main exhaust and 2 concentric rings (?) around the main turbo exhaust nozzle. I have no idea how they handled the intercooler (liquid cooling tied to the radiators?)
Date of this contraption is a little iffy. 5 prototypes were built, it was never flown. Some information was published in the 1950 and 1951 editions of Jane's for basic engine but it was never marketed. The 12-B engine is supposed to have received it's approval tests in 1951 as a simple engine and the 1951/52 Jane's says the integral propulsion version was "under development"
This is from pages 368-370 of Hispano Suiza in Aeronautics by Manuel Lage.

I have no idea what was supposed to be ready for production in 1948.

Let me ask this then; using the specifications B Bretoal2 shared earlier from Flight, how long would it take for Hispano to make either a beefed-up variant of the 12Z or a new engine to match the ~1,750 hp SL / 2,200 hp TO at ~930 kg given for the 12B Type 20 - assuming they started around late 1940 or early 1941?
Most of the V12's in this similar range started showing up in bulk around mid 1943 to early 1944, so perhaps a similar timeline for this theoretical Hispano?

 

[Shortround6]

Let me ask this then; using the specifications B Bretoal2 shared earlier from Flight, how long would it take for Hispano to make either a beefed-up variant of the 12Z or a new engine to match the ~1,750 hp SL / 2,200 hp TO at ~930 kg given for the 12B Type 20 - assuming they started around late 1940 or early 1941?
Most of the V12's in this similar range started showing up in bulk around mid 1943 to early 1944, so perhaps a similar timeline for this theoretical Hispano?

You need to go to a new engine.
Trying to beef up an existing engine (even a tenuous one like the 12Z) by close to 50% pretty much means you are changing everything. You might as well start with a clean sheet rather than keep beefing up a few parts here and few parts there and sometimes going back to on of the first modified parts.
It generally took 3-4 years to get a new engine into production. A lot depends on how much of a new engine you are building and how much was based off an existing engine, even if scaling up. Also depends on what else you are doing. P&W took about 3 years to build the R-2800 C, they started in 1940. But getting the R-2800 B into production, and helping several other companies build new factories and working on the R-4360 (which used the same cylinders) may have slowed things up a bit.
France had screwed themselves with partial take over of the Hispano company in France and Marc Birkigt stopping work on aircraft engines. SO they needed either new designers/engineers or promotion of existing personnel. Birkigt and also designed a lot of the tooling to make the existing HS engines so you need people to do that.
And you need to build, in large numbers, the HS 12Y in several different models.
It took Junkers quite a while to get the 213 into production, they may have started in 1939/40 (?) They took the option of keeping the existing bore-stroke and increasing the rpm.
Daimler Benz took the larger cylinder size option with the 603.
This is part of the reason that trying to go back in time and saying "well, it took only 3 years in the late 40s when they were at peace so they could have done it quicker in war".
I have no idea of what the guys working on the 12B used for late war technology in relation to alloys, bearings, lubrication and so on. P&W did a lot of work in the early part of WW II on bearings. But in 1944-46 when they were working on the post war R-2800s and R-4360 they already had a lot bearing knowledge built up. And a lot of other "stuff".

We also have to figure what we want the engine to do. Some of the late war 1750hp / 2200hp engines were 'sprint' engines. With the proper fuel and/or W/A they would do it. but they didn't increase the 30 min climb or longer cruise settings much. A late war DB 605 with a 1800hp rating does NOT make a good replacement for a DB 603 or Jumo 213 as a bomber engine. Please note that the P&W R-2800 at 2000hp T-O would never had worked in the B-29 as a replacement for the R-3350. The R-3350 was only rated at 200mp more for take-off but it was rated at 300hp or more for the long periods of time it took to get a B-29 up to operating altitude.

Kind of the reason that Avro went to the Griffons in the Shackleton's instead of high power Merlins.



It may mean that Hispano would have to shelve the 12Z while they work on the 12B and that leaves you with the 12Y-51 as the standard bearer for 1940-41-42 and into 1943.
That also may mean that they have to straighten out the 12Y-51 while working on the 12?? as the 12Y-51 had problems.
I have no idea of what the guys working on the 12B used for late war technology in relation to alloys, bearings, lubrication and so on.

 

[Shortround6]

A problem for me is that the French engine industry was operating at sub par levels during the 1930s.
H-S and G-R were the survivors with the other French companies operating on borrowed time. Maybe they were starved of contracts before the late 30s rush and then it was too late.
H-S 12Ys were having trouble with durability/reliability even in 1933/34 during the Soviet tests. The whole radial engine detour was a fiasco to put it politely. One book claims the 14 AA engine (45.2 liter) were getting pulled from the LeO 45 prototype after 18 hours of service. This threw the load for production onto the G-R 14N (38.7 Liters) . Likewise the failure of the 14 AB (26.1 Liters) necessitated the G-R 14M (19 Liters) being substituted in all of the planned aircraft that were slated to use the 14 AB.

Marc Birkigt had stopped production of motor cars in 1936 after nationalization and he also personally stopped work on the aero engines leaving his son Louis to oversee the Radial engine projects and other designers to work on the V-12s. How much the radial projects took resources from the V-12 side of things I don't know, radials were built in a new factory (?) but how much design staff was shared/borrowed at times?
Unfortunately the 12Y-31 engines in the MS. 406 have been described as fragile and wearing out quickly affecting it's combat performance in during the phony war. Worn engines means the planes won't perform up to "book" levels.
Using short lived engines works IF you can supply replacement engines and if you have a decent overhaul capability. Due the French efforts to build large numbers of new aircraft that may not have the been the case for France in 1939/40.
The 12Y-51 was known for having problems in Swiss service (the only large scale user, if Swiss service can be called large).
The French may have been able to solve some of the issues with the 12Y series and even build some of the lower powered 12Z versions in 1942/43. Which requires substantial re-tooling. Trying to build 1500-1600hp 12Z engines that are reliable enough for service use (even a much shorter lives than the Merlin) seems to be really pushing things.
The Problem is not with the fuel, it is getting the engines to hold together even at the lower power settings.

I don't know were the cross over point is from cheap/light disposable engines and expensive/heavy engines is. It may vary a lot depending on the Nation and the expected service.
But try to imagine the RAF trying to use H-S engines in the thousands of Lancaster's and Halifax's of bomber command the needing to replace them 3-4 times more often?

 

[Bretoal2]

A problem for me is that the French engine industry was operating at sub par levels during the 1930s.
H-S and G-R were the survivors with the other French companies operating on borrowed time. Maybe they were starved of contracts before the late 30s rush and then it was too late.
H-S 12Ys were having trouble with durability/reliability even in 1933/34 during the Soviet tests. The whole radial engine detour was a fiasco to put it politely. One book claims the 14 AA engine (45.2 liter) were getting pulled from the LeO 45 prototype after 18 hours of service. This threw the load for production onto the G-R 14N (38.7 Liters) . Likewise the failure of the 14 AB (26.1 Liters) necessitated the G-R 14M (19 Liters) being substituted in all of the planned aircraft that were slated to use the 14 AB.

Marc Birkigt had stopped production of motor cars in 1936 after nationalization and he also personally stopped work on the aero engines leaving his son Louis to oversee the Radial engine projects and other designers to work on the V-12s. How much the radial projects took resources from the V-12 side of things I don't know, radials were built in a new factory (?) but how much design staff was shared/borrowed at times?
Unfortunately the 12Y-31 engines in the MS. 406 have been described as fragile and wearing out quickly affecting it's combat performance in during the phony war. Worn engines means the planes won't perform up to "book" levels.
Using short lived engines works IF you can supply replacement engines and if you have a decent overhaul capability. Due the French efforts to build large numbers of new aircraft that may not have the been the case for France in 1939/40.
The 12Y-51 was known for having problems in Swiss service (the only large scale user, if Swiss service can be called large).
The French may have been able to solve some of the issues with the 12Y series and even build some of the lower powered 12Z versions in 1942/43. Which requires substantial re-tooling. Trying to build 1500-1600hp 12Z engines that are reliable enough for service use (even a much shorter lives than the Merlin) seems to be really pushing things.
The Problem is not with the fuel, it is getting the engines to hold together even at the lower power settings.

I don't know were the cross over point is from cheap/light disposable engines and expensive/heavy engines is. It may vary a lot depending on the Nation and the expected service.
But try to imagine the RAF trying to use H-S engines in the thousands of Lancaster's and Halifax's of bomber command the needing to replace them 3-4 times more often?

Some points:

Early days (or years...) of the LeO 451 are well known: 13 HS 14Aa engines in 50 flight hours in 18 monthes for the 451-01.

Hispano-Suiza had only one production site in Bois-Colombes; the "decentralized" factory in Tarbes (800 km from Paris), built with State funds, did not begin shipping engines before early 1940.

More generally, the inferiority of French engines in the late 1930s can be explained by the absence of the new generation of models: they were in gestation in 1935-1936, but the social and political troubles that lasted until the aftermath of the Munich crisis prevented their release and development. Marc Birkigt was completely demoralized because the "theft" of his French company occurred at a time when Spain was sinking into civil war, and Paul-Louis Weiller found himself embroiled in a thousand legal cases, and was also very poorly regarded by the most active of the Air Ministers, Guy La Chambre (one of the most long-lasting ones - two years and two monthes !).

The LeO 451, Amiot 350 and Bloch 174 should have received engines of the 1,200/1,300 hp class such as the HS 14Aa, G&R 14P or 14R, HS 12Z, but had to make do with 20 to 25% less HP because these engines were not ready (the 14P will be abandoned...).

Another problem was that of the homologation of the engines. This was only done by means of bench tests at 0m (admission through a vacuum box to simulate the altitude). Real flight tests only took place from the end of 1938 (Munich, again!), accompanied by longer and tougher tests for the bench tests - Paul-Louis Weiller dared to protest against the failure of the homologation of the 14P on the bench for that it had been designed "according to the old standards".

The result was that prototype engines were flown on prototype aircraft, considerably extending the development time; in addition, most prototypes were ordered for only one example, which might be catastrophic in the event of an accident!

That being said, I think that once the beginning of the war was over, and the errors of the mobilization were corrected (the engineers returned to their offices and not to the Maginot Line...), there was a real national upsurge and that enormous efforts were made to catch up on quality and quantity, engines and airframes. But no one knows what the French aeronautics industry would have become if Gamelin had not sent his troops to Belgium...