Could France make due with just two fighters?

The HS 12Y engines have had problem of insufficient power, much more acute than a problem of low availability.

Admiral Beez said:

I like the D.520 naval variant. Of all the European in-line-powered single-engine fighters intended/modified for carriers (Seafire, Sea Hurricane, Fulmar, Firefly, Bf 109T, Reggiane Re.2001), I'd say the folding wing D.790 as it was continually developed would have been only second to the later folding wing Seafire or later Firefly.

View attachment 593024

View attachment 593025
Images courtesy of DEWOITINE D.790

Click to expand...

Oh man, that is pretty!

To comment on the OP, at least the last two ( C-714 and FK-58) should dropped like a hot potato. Absolutely useless and a waste of resources. Better to focus on any of the other 4 which is two more than the OP ask, but i guess each have their place and charm, the MS-406 and MB-152 the first generation, to be replaced by D-520 and VG-33 and radial MB-155, still a better use of resources compared to OTL.

Of course, perhaps a more rational approach was to replace the MS-406 with MS-450 (wasn't it about as fast as D-520, and presumably have some structural commonality with the MS-406?), and replace the MB-152 with MB-155. That means no VG-33 and no D-520 (which was pretty good), but they can't do worse than OTL i would think.

The problem wasn't so much the aircraft as was the French procurement disorganization and factory disruptions.
Source: hazy recollections of prior Forum discourse. This is not my area of expertise as there were very few carrier engagements between Germany and France.

Those problems were horrific, but from what I understand, they were starting to be sorted out just in the last 3-6 months before the war actually broke out and both production and preparation were ramping up very fast in 1940. They had ordered a ton of aircraft (including some quite good ones) from the US, and several of their own types were very promising. For 1940, a Dewoitine D.520 is a very nice aircraft. They were still in use as late as 1943 and doing pretty well. The VG 33 also looks very good, and especially some of the later variants (assuming they could really make the engines produce that much power, which they seemed confident they could... and they were also looking at putting Merlin or Allison engines in them).

On top of that they had the Hawk 75 which we know was almost on par with Bf 109E in the Battle of France (they just needed more of them), they had Boston and Maryland bombers coming (both quite good at that time), early P-40s, even early P-38s IIRC. They had the very promising Breuget 693 fast / light bomber, the well regarded LEO 451 medium bomber, and an excellent recon plane in the Potez 174. And some weird ones which seemed to do well for reasons I don't fully grasp the strange Latecore 298 float plane torpedo bomber seemed to be pretty good in actual service.

I agree ditch the Caudron 710, they put those poor Polish pilots into them and their lives were wasted.

It's possible MS-450 and Bloch 155 may have fixed the problems with their precursor types.

The question is, how much more time did they need? I know the D.520s arrived literally days before the battle of France started. The VG-33 mostly hadn't had their engines put in yet. P-40s were (I think?) on the way as were Bostons and Marylands. How much more time did they actually need? If the air war had gone better, the French might have had time to rally and put the war into a more attrition scenario. The Germans were relying very heavily on the Stuka for their breakthroughs. Their tanks were fairly small and undergunned to face some of the better French tanks like the SOMUA S.35.

Could they have had a chance with 3 more months? 6 more?

Wild_Bill_Kelso said:

The VG 33 also looks very good, and especially some of the later variants (assuming they could really make the engines produce that much power, which they seemed confident they could

Click to expand...

Which they could not make post war. Also please look at what the Swiss did to get comparable power during/after the war. It took the Swiss until 1943 (?) to reliably get the rated power out of their engines.

Wild_Bill_Kelso said:

They had the very promising Breuget 693 fast / light bomber

Click to expand...

Don't confuse heroic/desperate crews with promising aircraft.
Used the same engines as the German HS 129, in fact some them may have been the same engines taken off of Breuget 693s.
Figures given on Wiki do not seem to match the text. Range is given as 840 miles but the text says they did not have to range to evacuate to North Africa and is roughly 500 miles from the south coast of France to Algiers?
Using two 14 cylinder engines to carry the same forward firing armament as the MS 406 is a rather French thing to do. How promising it is???

Wild_Bill_Kelso said:

I don't fully grasp the strange Latecore 298 float plane torpedo bomber seemed to be pretty good in actual service.

Click to expand...

The Defiant worked real good too, twice.
Trying to draw conclusions from a very limited number of engagements is difficult.

Shortround6 said:

Which they could not make post war. Also please look at what the Swiss did to get comparable power during/after the war. It took the Swiss until 1943 (?) to reliably get the rated power out of their engines.

Click to expand...

Postwar interest in piston engines had waned a great deal, for smaller engines even more so, and if you did want an engine, you could get a Merlin pretty cheap.

Switzerland had 4 million people just before WW2, France had 42 million. And a lot more money, experts, factory space, raw materials from overseas colonies, and every other kind of resource you can think of.

I don't know for sure they could make the power they believed they could, but if you look at what happened in the late 1930s, the power of the much maligned 12-Y, even with intermittent funding and very bad management, increased along a fairly predictable curve, going from 800 hp in 1934 to 1,000 hp in 1936. In 1939 alone the D.520 went from a 922 hp 12Y-45 to a 950 hp 12Y-46, and by June 1940 they were just completing trials with an 1,100 hp 12Y-51 with some kind of improved supercharger.

Shortround6 said:

Don't confuse heroic/desperate crews with promising aircraft.
Used the same engines as the German HS 129, in fact some them may have been the same engines taken off of Breuget 693s.
Figures given on Wiki do not seem to match the text. Range is given as 840 miles but the text says they did not have to range to evacuate to North Africa and is roughly 500 miles from the south coast of France to Algiers?
Using two 14 cylinder engines to carry the same forward firing armament as the MS 406 is a rather French thing to do. How promising it is???

Click to expand...

You should look at a model or photos at scale. These are tiny aircraft, definitely smaller than a Hurricane (even though slightly wider wing span). A 300 mph strike aircraft, with a 700 mile range, cannon armament and a 1,000 lb bomb load in 1940 definitely has potential as a design. Objectively. And all this with 700 hp engines. Gnome Rhone may not be your favorite but they could have improved the power on those. The Breuget 693 also weighed 1,000 kg less than an HS 129 (and was 50 mph faster0 so I don't think it's an apt comparison.

However, it's true that they didn't fare that well in combat. They were not expecting multiple 20mm AA guns that the Germans had. I think they could have found a role for them though. It compares well to a Boston and those certainly did well.

Shortround6 said:

The Defiant worked real good too, twice.
Trying to draw conclusions from a very limited number of engagements is difficult.

Click to expand...

That is a fair point, and the Latecore doesn't look like it ought to be effective. But you could say the same for Swordfish and Albacore which did a lot better than one would expect based on the numbers... (and the looks)

The point about limited data sets also applies to the short career of the 693, I'd say....

Wild_Bill_Kelso said:

Postwar interest in piston engines had waned a great deal, for smaller engines even more so, and if you did want an engine, you could get a Merlin pretty cheap.

Switzerland had 4 million people just before WW2, France had 42 million. And a lot more money, experts, factory space, raw materials from overseas colonies, and every other kind of resource you can think of.

I don't know for sure they could make the power they believed they could, but if you look at what happened in the late 1930s, the power of the much maligned 12-Y, even with intermittent funding and very bad management, increased along a fairly predictable curve, going from 800 hp in 1934 to 1,000 hp in 1936. In 1939 alone the D.520 went from a 922 hp 12Y-45 to a 950 hp 12Y-46, and by June 1940 they were just completing trials with an 1,100 hp 12Y-51 with some kind of improved supercharger.

Click to expand...

In 1945-46-47 and even later, the French and Italians and British were all scrabbling for any sort of foreign trade. They were trying to sell anything they could cobble together. And cobble is pretty much accurate as most of the French and Italian factories have been bombed or fought over in land battles. Prewar workers were gone (some returned?). France was actually trying to sell Jumo 213s seeing as how the Germans had left a production line there in 1944. Also Argus V-12 air cooled engines.
The Swiss had pretty good industrial base, not all chocolates and cuckoo clocks
Swiss added something like 30KG to the crankshaft of the Hispano engine amongst other changes.
The Problem with the Hispano was that it did not start in 1934 or even 1933 or 1932, It started in 1928 at 650hp without a supercharger. It may have been a very fine engine at 650-700hp in the late 20s or early 30s. They did change things and strengthen things as they went. However they kept the same bore and stroke, the same valve set up in the heads, they went back from an intended 2600rpm limit to 2400rpm due to torsional vibration problems. Which reared their head in later developments. It was only in the Z series engines that they gained much weight (over the weight of reduction gears and supercharger and blocks/cranks that were designed for 700hp are too small for 1000+ hp.
Russians wound up adding around 200lbs to the engine.
Swiss in the YS-2 version wound up at 1510lbs for 1300hp T-O and 1410hp at 4800 meters at 2600rpm and using fuel injection and 93 octane fuel and that was in 1946/47.

Wild_Bill_Kelso said:

. These are tiny aircraft, definitely smaller than a Hurricane (even though slightly wider wing span). A 300 mph strike aircraft, with a 700 mile range, cannon armament and a 1,000 lb bomb load in 1940 definitely has potential as a design. Objectively. And all this with 700 hp engines. Gnome Rhone may not be your favorite but they could have improved the power on those. The Breuget 693 also weighed 1,000 kg less than an HS 129 (and was 50 mph faster0 so I don't think it's an apt comparison.

Click to expand...

Gnome Rhone had some issues.
Maybe it was not yet maxed out, however it had some serious issues.
G-R 14 M engine......................................P&W R-1340 Wasp (engine from a T-6)
1159cu in./19 liters.........................................1340cu in/22 liters
924lb...........................................................................930lbs
700hp T-O/3030rpm............................................600hp T-O/2250rpm
660hp 4000 m/3030rpm....................................600hp 1900 m/2250rpm

The 14 M was cute, it was small, only 950mm in diameter. but it only had two bearings for the two throw crank and didn't have a lot of room to Grow. The R-1340 is the updated version of the original Wasp of 1925. P&W wasn't dumb enough to push it any further even though Doolittle had gotten 900hp out of one in the early 30s using water injection.

The comparison to the HS 129 may not be apt but part of the problem with the Breuget in service was the total lack of protection. No armor and unprotected tanks. It seems to have been rugged which allowed shot up planes to regain base. They tried several different engines in them but even the US P&W R-1535 engine was not a good fit. It's large size and poorer streamlining canceled out what ever extra power it had. Trying to fit the G-R 14N engines meant that the side vision was even worse than the P&W powered version although shear power did give more speed.
Normal bomb load was eight 50kg bombs inside the fuselage. Some examples may have had a supplementary 31inp gal tank in each engine nacelle, bringing total fuel to 217imp gal.

Well, I think this is a little short sighted. The Gnome Rhone 14M wasn't the only engine they made in this series. The GR 14N which was in the Bloch 152, and had a second row of cylinders, produced almost double the power (1,180 hp) for an additional 200 lbs or so, and that's on 87 octane gas.

The Gnome Rhone 14K was the basis for the IAR K14 which powered the IAR 80 fighter, and the Piaggio P.XI which powered the SM.79 and the Re 2000, all successful aircraft. And all producing around 1,000 - 1,200 hp.

I don't think there is any real reason you couldn't put a 14N on the Breuget 693 - in fact they did exactly that with the Br 697, as an experimental heavy fighter, and according to Wiki "it was as fast as a Bf 109 and had a sensational rate of climb". I do not have trouble believing that as it's 50% more power.

Wild_Bill_Kelso said:

The Gnome Rhone 14M wasn't the only engine they made in this series.

Click to expand...

Define series.
The 14M was 19 liter engine. The 14K, 14N and 14R were all 38.7 liter engines with exactly the same size cylinders as a Hercules. Weights varied enormously.
The 14N of around 1200hp was about 1250-1400lbs depending on exact model. The 14Ks were several hundred lbs lighter. The 14R was lot heavier but they only made very small handful of those and they were never used in a production aircraft.

Wild_Bill_Kelso said:

The GR 14N which was in the Bloch 152, and had a second row of cylinders, produced almost double the power (1,180 hp) for an additional 200 lbs or so,

Click to expand...

Se above.

Wild_Bill_Kelso said:

The Gnome Rhone 14K was the basis for the IAR K14 which powered the IAR 80 fighter, and the Piaggio P.XI which powered the SM.79 and the Re 2000, all successful aircraft. And all producing around 1,000 - 1,200 hp.

Click to expand...

You forgot the Soviet M-85 (?) though M-88 series but that shows us the difference between license built and "the basis for".

The problem is "if" a certain airframe can take a substantially larger engine or not.
Not proof but the Grumman F5F/P-50 did not change from the R-1535 engine to the R-1830 engine when the R-1535 version was canceled. They changed to the Wright R-1820 engine which was fatter, but lighter than the R-1830.

What were they willing to change to use the bigger engines on a production aircraft?