Advanced French Fighters vs 1942/1943 contemporaries (1 Viewer)

[Shortround6]

I will also note that water injection, higher boost with better fuel is a short term solution. Like combat, It can be very useful and life saving.
It rarely does anything for getting bombers to altitude (20-30 minute climb) or for high speed cruise.

Japanese are about the only ones that used water injection for more than a few minutes in some engines. But they traded weight for the ability to run at the higher power levels.
American naval fighters carried around 8-10 gallons of W/A, P-47s carried 25 gal (?), Germans used around 25 gal (?).
Problem is if you don't need it for combat it doesn't help you get back to base. You are carrying 70-200lbs of dead weight.

Some Fw 190s could inject extra fuel into the intakes to get some of the same effect. The Allied aircraft did not have to do this, their carbs would flow enough fuel at high throttle openings to do pretty much the same thing. The German fuel injection system would not work that way. It gave the engine the fuel it needed to make power. It could not flow an extra gallon a minute through the intake and supercharger to cool the intake air and have the surplus unburned fuel carry heat away from the cylinders (lots of black smoke). The Germans cold get black smoke but not quite like some the allied planes.
R-2800 powered planes were set up to flow around 1 gallon per minute less fuel when the water injection was engaged. The extra fuel had been being used as a coolant.

 

[Bretoal2]

The Government thinks the 14AA is the greatest thing since the croissant and plans much of their bomber program around it.

No. The French "Service Technique" thought the 14AA and 14AB were an excellent way to break the monopolistic situation = Hispano-Suiza for liquid-cooled engines, G&R for air-cooled ones.

The 14K-10 series(?) engines show better reliability but not much more power.

14K 10 ?? Never heard of this.

The G-N 14N is used to fill some of the gaps but is still a bit down on power.

No. The 14N had a re-birth when it was fitted with 14P (14R forerunner) cylinder heads. (14N-21 and later). But 14P itself was a failure (6 unsuccessful type-tests).

H-S is working on the 12Y as a fall back for the 14 AA but several years have been lost

No. The 12Y had a re-born when fitted with Planiol-Szydlowski supercharger. And 12Z was a technical mistake. And don't forget French policy which had decapitated the Company - after a partial acquisition by the State and the appointment of Robert Blum, son of the leader of the Front Populaire as technical director, Marc Birkigt had no longer any interest in its engines and worked essentially on 404 cannons.

By the time we get to 1939 and early 40 the 14 AA is pretty much trash and the mad scramble for substitute engines is on.

No. By the fall of 1938, Hispano-Suiza had new versions of the 14AA with improved cooling area and dynamic damper in its crankshaft. But the Air Minister Guy La Chambre forbade these engines ! Nevertheless, they performed well in the Latecoere 570 and Koolhoven FK 58.

The G-R 14R engine was 150-200lbs lighter than other 14cylinder engines making about the same claimed power.

Yes (at last..) . Most of French engine companies said their products were "light", but they forgot that this was meaning "unable to whithstand extra power".

 

[tomo pauk]

No. The French "Service Technique" thought the 14AA and 14AB were an excellent way to break the monopolistic situation = Hispano-Suiza for liquid-cooled engines, G&R for air-cooled ones.

Was the "Service Technique" right in their expectations?
Further - how do the 14AA and 14AB break the V12 monopoly of the Hispano Suiza company?

 

[tomo pauk]

I will also note that water injection, higher boost with better fuel is a short term solution. Like combat, It can be very useful and life saving.
It rarely does anything for getting bombers to altitude (20-30 minute climb) or for high speed cruise.

I'm not sure that anyone here is suggesting that the water-alc injection is a solution for improving the long-term power levels.

 

[TM06]

So we have a 1,850~2,000 hp radial for 1943 or thereabouts, that leaves the 12Z to determine. We could apply the same ideas from the 14R (MW, Fuel Injection, 100 octane fuel, more boost) to get an idea. Looking at the VK-107 again might be the best choice, since it's fundamentally similar.
If we take the fact that France's development was pushed back by 4 years, at a basic level this could mean that HS could start prototyping the 12B in 1941 (it started prototyping in 1945) and make production status in 1944 (production status in 1948), but that's just outside the area of this discussion.

 

[Shortround6]

No. The French "Service Technique" thought the 14AA and 14AB were an excellent way to break the monopolistic situation = Hispano-Suiza for liquid-cooled engines, G&R for air-cooled ones.

Maybe both. Several other countries favored one type of cooling over the other at times during the 30s. USN favored air, The US Army favored liquid cooled. They just couldn't get any good liquid cooled engines for most of the 30s.

14K 10 ?? Never heard of this.

Badly written? 14 K s that had higher numbers than -10?

No. The 12Y had a re-born when fitted with Planiol-Szydlowski supercharger.

They had fooled around with several changes, like changing the connecting rods and changing the compression ratio. But aside from fooling around the supercharger gear ratio to suit different aircraft (flying boats vs???) they hadn't changed a lot. The Planiol-Szudlowski supercharger was a big improvement but it had little to do with the engine.
The Y-50/51 engines showed what they should have been doing. Changing the crankshaft and crankcase to allow for 2500rpm and putting larger valves in the exiting heads, Not where they needed be for 1941-42 but would have improved things a lot in 1940 to had the -51 inproduction and service aircraft instead of prototypes.

No. By the fall of 1938, Hispano-Suiza had new versions of the 14AA with improved cooling area and dynamic damper in its crankshaft. But the Air Minister Guy La Chambre forbade these engines !

La Chambre might have done as much as anybody to insure German success but in this case, can you really blame for not trusting what H-S was saying? He was running out of time and if he chose wrong (as he had done before) there was no time to fix it.

Yes (at last..) . Most of French engine companies said their products were "light", but they forgot that this was meaning "unable to whithstand extra power".

And that is part of this discussion. Expecting some French engines to show the same ability of other engines to be "improved" when they were so much lighter than the competition.

 

[Bretoal2]

Was the "Service Technique" right in their expectations?
Further - how do the 14AA and 14AB break the V12 monopoly of the Hispano Suiza company?

It was a beginning.

And Paul-Louis Weiller (G&R chairman) was very unpopular in some officials cenacles. He was suspected to only want to sell his engines, not to improve them. And this was maybe right...

(number of patent licences delivered to G&R in the 1930's ans 1940's, i.e. in about 15 years = TWO !)

 

[Shortround6]

So we have a 1,850~2,000 hp radial for 1943 or thereabouts, that leaves the 12Z to determine. We could apply the same ideas from the 14R (MW, Fuel Injection, 100 octane fuel, more boost) to get an idea. Looking at the VK-107 again might be the best choice, since it's fundamentally similar.

YES!!!
VK-107 weighed around 789kg!
And it didn't work until 1946 ? (if then)
The Swiss YS engines went around 685-705kg.
The Spanish 12Z-89 engine gave about 1400hp at 4500 meters for 640kg in 1947?
French 12Z-1 was rated at more power (400hp? more) at the same RPM using less boost and was 20kg lighter.

We are circling around to where we started.
The French engines don't seem to be strong enough (weight) to stand up to the power that is wanted.

 

[bf109xxl]

Direct fuel injection was a way to make the substantial valve overlap to work. Increased valve overlap = increased power (obviously, up to a point).
If there was no change to the valve train (= basically to the camshafts in this case), the gain in power due to dir. fuel injection was probably negligible since there is no incraesed valve overlap.

I know about the effect of valve overlap. I was talking specifically about the M-82 with a valve overlap of 45° (the same for carburetor and DI versions, was increased by 2.5% in the latter series), in which the effect of purging and cooling of the combustion chamber was clearly insufficient. That is why it is difficult to judge what exactly caused the power gain. And I suspect that the French engineers would hardly decide to make radical changes in the valve timing. Conclusions: the results for the M-82 cannot be used to evaluate the effect of direct injection, and the 10% gain estimate may be overly optimistic considering engineering conservatism.
By the way, what carburetors were used on the 14R?

The benefits wrt. the reliable and uniform fuel flow should still be felt, however

It's clear.

 

[TM06]

YES!!!
VK-107 weighed around 789kg!
And it didn't work until 1946 ? (if then)
The Swiss YS engines went around 685-705kg.
The Spanish 12Z-89 engine gave about 1400hp at 4500 meters for 640kg in 1947?
French 12Z-1 was rated at more power (400hp? more) at the same RPM using less boost and was 20kg lighter.

We are circling around to where we started.
The French engines don't seem to be strong enough (weight) to stand up to the power that is wanted.

No need to be sarcastic, it's just the most reliable starting point.
If we assume that the 12Z wouldn't be able to handle the same power as the VK-107 (~1,650 hp?) without a major redesign, that would put an upper limit of about 1,500~1,550 hp for the 12Z. That's not bad for a lighter engine around 1942-1943.

 

[tomo pauk]

I know about the effect of valve overlap. I was talking specifically about the M-82 with a valve overlap of 45° (the same for carburetor and DI versions, was increased by 2.5% in the latter series), in which the effect of purging and cooling of the combustion chamber was clearly insufficient. That is why it is difficult to judge what exactly caused the power gain. And I suspect that the French engineers would hardly decide to make radical changes in the valve timing. Conclusions: the results for the M-82 cannot be used to evaluate the effect of direct injection, and the 10% gain estimate may be overly optimistic considering engineering conservatism.

I'd say, too, that the gain in power on the Shvetsov radials was meager after the d-i system was installed.

 

[TM06]

So for a quick engine recap, we have:
- A 1,850~2,000 hp radial in a developed 14R.
- A 1,450~1,500 hp inline in a developed 12Z, with the possibility of a 1,850 hp 12B for 1944 onwards.
Both of those are quite solid for the time-frame, providing a notable advantage in 1941 but tapering off in 1942 and 1943.
The 14R would be providing similar power to the ASh-82FN and BMW 801 D-2, along with superior power to the Hercules XVI and R-2600 Twin Cyclone.
The 12Z would be behind the Merlin 61 and DB 605AM, but equal with the DB 605A-1 and ahead of the V-1710-39 and VK-105PF.
Any objections?

 

[Shortround6]

Any objections?

A bunch.

The 14R would be providing similar power to the ASh-82FN and BMW 801 D-2, along with superior power to the Hercules XVI and R-2600 Twin Cyclone.

Ah, the wonders of French engineering.

engine............................Bore x stroke............Displacement............weight................RPM...........................Power at altitude/s
14R-historical(47)...........146x165....................2360ci/38.7l..............825kg...............2600rpm......................1760hp/3300ft (low gear
14R-proposed.................146x165....................2360ci/38.7l...............?????................2600rpm.?...................1850hp/????
Hercules XVI.....................146x165....................2360ci/38.7l...............868kg..............2900rpm......................1735hp/500ft
ASh-82FN.........................155.5x155.................2514ci/41.2l...............910kg..............2400rpm........................1700hp/T-O
BMW 801 D.....................156x156.....................2560ci/41.7..............1012kg.............2700rpm.......................1740?/1500 meters?
R-2600 BA........................155x160......................2603/42.7...................895kg.............2500rpm........................1700hp/4100ft

Use the smallest, lightest engine of the bunch, and get more power. The 1947 numbers are supposed to be for 100/130 fuel and using 10.1lbs/50.2in boost

The 12Z would be behind the Merlin 61 and DB 605AM, but equal with the DB 605A-1 and ahead of the V-1710-39 and VK-105PF

Like to see the time line for this. In 1941 the French would barely have the 12Y-51 running as a production engine, assuming they fixed it earlier than the Swiss could fix it.
The V-1710-39 was a 1941 engine (ordered in 1940 with a few prototypes flying). The late 1942 Allison was the -81 that gave 1125hp at 15,000ft. and would stand up to over 1400hp at altitudes under 10,000ft. It still pretty much sucked over 20,000ft though.
Now please note that the -81 engine had a different crankshaft and different crankcase the early -39 engine. Also note that very late Allison's got another new crankshaft (which can and was dropped into old engines at overhauls/rebuilds) and power went to 1325-1425hp military and 1600-1800hp WEP. But this required a bunch of new parts, like new piston rings, valve springs and other stuff.

- A 1,850~2,000 hp radial in a developed 14R.

A yes, the wonders of French unobtanium and/or other exotic alloys.

- A 1,450~1,500 hp inline in a developed 12Z, with the possibility of a 1,850 hp 12B for 1944 onwards.
Both of those are quite solid for the time-frame, providing a notable advantage in 1941 but tapering off in 1942 and 1943.

The French not surrendering in 1940 does not catapult them into the forefront of engine development in 1941-42.

The two French engines (14R and 12Z) are both light for the power desired. You either have to limit rpm or limit boost pressure (BMEP) to keep from wrecking the engines regardless of the type of fuel or wither you use fuel injection or not.

The US got 1900hp out of the R-2600 in late 1943, about 2 years after they got the 1700hp version into production. Trouble is that it is completely different engine. New crankshaft and new crankcase allowed higher rpm. New cylinders and heads and new way of making fins (sheet metal rolled in groves in the cylinder barrel ) kept the engine cool.

Water injection can do two things. It can help you make power, it can also keep the top end from melting down. It does nothing to keep the rods, crankshaft or crankcase from bending, cracking or breaking.
You can trade engine life for power but that only goes so far. Note the limited amount of power the Soviets OK'd for their engines. When your engines are crapping out at under 100 hours to begin with you can't push them to larger gains.

 

[Bretoal2]

It does nothing to keep the rods, crankshaft or crankcase from bending, cracking or breaking.

The 14 R was well known for the fragility of its plain bearings. The approval of its elder brother 14P failed several times due to destroyed bearings (and was never achieved, making this engine an entire failure).

For the record, the 14R and its 18-cylinder evolution (18R) were very quickly abandoned after the Liberation, SNECMA, successor to Gnome Rhône, having found itself unable to raise these engines to the required standards of power and reliability. - And SNECMA enventually build licensed Bristol Hercules.

 

[Shortround6]

The 14 R was well known for the fragility of its plain bearings. The approval of its elder brother 14P failed several times due to destroyed bearings (and was never achieved, making this engine an entire failure).

For the record, the 14R and its 18-cylinder evolution (18R) were very quickly abandoned after the Liberation, SNECMA, successor to Gnome Rhône, having found itself unable to raise these engines to the required standards of power and reliability. - And SNECMA enventually build licensed Bristol Hercules.

And that says something. Tooling up to build sleeve valve engines and then building them is usually considered more expensive than setting up for and building poppet valve engines.
Licensing the Hercules eliminates the R & D costs.

I will also note that the Hercules engines that SNECME built were very different from most of the WW Hercules engines. Bristol was working on many of the improvements in 1944-45 engines.
Different crank, bearings and main cases, Different cylinders (with more bolts holding them down) and different cylinder heads.
The last cylinder heads were copper based with close spaced fins, a steel skirt and an inner face covered in nickel to resist corrosion.
Head ran 25 degrees C cooler than the previous heads.

 

[Bretoal2]

And that says something. Tooling up to build sleeve valve engines and then building them is usually considered more expensive than setting up for and building poppet valve engines.
Licensing the Hercules eliminates the R & D costs.

I will also note that the Hercules engines that SNECME built were very different from most of the WW Hercules engines. Bristol was working on many of the improvements in 1944-45 engines.
Different crank, bearings and main cases, Different cylinders (with more bolts holding them down) and different cylinder heads.
The last cylinder heads were copper based with close spaced fins, a steel skirt and an inner face covered in nickel to resist corrosion.
Head ran 25 degrees C cooler than the previous heads.

Yes, I had one of these alu-copper "junk head" in my hands.

 

[TM06]

Like to see the time line for this

My idea went something like this;
1940: 12Y-50/51 becomes mass-produced late in the year, 14N-48/49 becomes mass-produced a bit earlier.
1941: 12Y-50/51 still the primary inline and 14N-48/49 still the primary radial, limited deployment of the 12Z and 14R (something like field testing). 12Y-51 gains the S-P supercharger. HS see the dead-end of the 12Z and start working on the 12B.
1942: 12Z and 14R become mass-produced slowly, gradually phasing out the 12Y and 14N, other engines start surpassing the 12Z and 14R late in the year. 12Z gains the S-P supercharger.
1943: 12Z and 14R reach theoretical performance limit mentioned prior, with the 12Z becoming a mediocre engine and the 14R still being solid.
1944: 12B finishes prototyping and is rapidly introduced to mass production (with teething issues).

The French not surrendering in 1940 does not catapult them into the forefront of engine development in 1941-42.

Rather than being at the forefront, I was thinking more around the average range. Going deep into horsepower but way behind on reliability. If they do start to care about reliability, then the decreased power isn't too big of an issue since they're still light engines. Also remember that this could be the non-embargo route as well, which is an arguably better position.

 

[bf109xxl]

ASh-82FN.........................155.5x155.................2514ci/41.2l...............910kg..............2400rpm........................1700hp/T-O

2500 rpm/1850 hp on 5 min T-O

 

[TM06]

S Shortround6 What would be your timeline for this type of thing? You seem to disagree with me on a lot of things, so I'd like to see what you think would happen. From 1940 to either 1943 or 1945.

 

[Shortround6]

French license Allison V-1710s and Wright R-2600s and scrap the domestic stuff. Of course this means getting the machinery from the US.
Keep making the HS-45/49 until the Allison's show up. Stuff them in the D.520s. Maybe lengthen the tail a bit.
MB 155 is the radial engine fighter short term.
Stuff the R-2600s in the MB-157 as fast as possible.
Beg for Spitfire IXs in 1942/43.

Basically the French were trying to flog a pair of dead/dying horses with the H-S and G-N engines and were trying to save themselves by hitching smaller carts to them to keep up with the neighbors. Unless the French can pull off a Swiss YS-2 type conversion by 1942 just give the H-S engines a decent funeral.

In 1932 H-S was making the 12Ybr engine that weighed about 415kg for a 36 liter engine including reduction gear and but without supercharger.
There were earlier engines that used the same same bore and stroke.

IN 1927 RR was making the Kestrel and around 1932 the unsupercharged version was about 410kg for a 21.25 liter engine. Most versions could run at 2700rpm but best power was often lower depending on fuel, compression and supercharger.

In 1930 a US catalog show 4 US liquied cooled V-12s.

The Curtiss D-12 of 18.8 liters and 435hp and running at 2300rpm. Direct drive, no supercharger. Weight 685lbs. This was an early 20s (1921) engine that provided the inspiration for Kestrel. Had 4 valve heads.
The Curtiss Conqueror (1924-26) but still used in the mid 30s. A 25.7liter (1570ci) engine that came both direct drive and geared. 755lbs direct and 845lbs geared. Power was pretty much limited to 600hp even with a turbo charger. 2400rpm. 4 valves per cylinder.
Packard A-1500. 1924 and later. The 3A of the late 20 offered 600hp at 2500rpm from an 915lb geared engine. 4 valves per cylinder. Wiki is both right and wrong. They built 29 of the 1A version but Wiki leaves out the 200 2A version and about 19 of 3A version.
Packard was also offering the A-2500 series starting in 1924. A 41 liter (2500ci) engine that was offering 800hp for T-O at 2000rpm ungeared and 850-900hp at 2500-2600rpm geared. 4 valves per cylinder. No supercharger. Weight was about 1120lbs direct drive and 1385lbs with reduction gears.

A few notes here. The USAAC was trying to replace all four of these engines with Hyper engines and Allison during the 1930s after a brief flirtation with air cooled engines (French were not the only ones, just a little later). These 1920s engines did not display modern (1930s) thinking as to bore and stroke or other construction features. The Packard A-2500 made a return as a marine engine and thousands were made for PT/MTB/MGBs using a bit heavier construction, superchargers and much better gasoline that the late 1920s stuff.

Hispano and France were slapping band-aids, splints, and athletic tape on a patient that needed organ transplants.