Inches and feet and gallons and pounds got mankind into controlled flight, they won WW2, they took us to the moon and created modern computers and the Internet. Not bad for an "inferior" system.
Advanced French Fighters vs 1942/1943 contemporaries (13 Viewers)
The question is how long could Germany fight a protracted war against Britain and France without running out of money or resources without plundering France, Greece,Russia Norway and Denmark to name a few. What would happen to German forces in occupied Norway and Denmark?Would they withdraw , be reinforced or defeated by Britain and France which would allow Iron Ore shipments from Sweden to German to be disrupted.Then you have Russia, without the invasion of Russia, would the Russians annex Romania to gain control of the Oil fields.
Steamed_Banana
Staff Sergeant
- 1,140
- Sep 29, 2025
It gets very hard to predict what happens after we change a major thing like whether France falls. It's very hard to imagine France managing to hold out though if their military was better organized they probably could have. But in anything like a realistic scenario I can only really imagine a few more months at the most. Unless you reorganized the entire French army.
ThomasP
Chief Master Sergeant
Another aspect of 'what if France does not fall when it did historically'.
The French Mediterranean fleet would be available. Not an overall war winner, but many of the problems the British navy faced in the MTO could be minimized. On paper and in theory, the French navy could stand off the Italian navy all by itself. The early-war French fleet combined with the British fleet could (probably would) prevent the Italians & Germans from maintaining any sizable force in North Africa.
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The French Mediterranean fleet would be available. Not an overall war winner, but many of the problems the British navy faced in the MTO could be minimized. On paper and in theory, the French navy could stand off the Italian navy all by itself. The early-war French fleet combined with the British fleet could (probably would) prevent the Italians & Germans from maintaining any sizable force in North Africa.
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ThomasP
Chief Master Sergeant
Addition to the above.
With France still in the fight, a significant number of airbases would be available in Tunisia - not just Malta. How much would this affect the supply routes?
Most of Sicily would be reachable from airbases in Tunisia (the far side of Sicily is only about 300 miles).
With France still in the fight, a significant number of airbases would be available in Tunisia - not just Malta. How much would this affect the supply routes?
Most of Sicily would be reachable from airbases in Tunisia (the far side of Sicily is only about 300 miles).
The aircraft consistently overlooked in these lists is the Amiot 351/354.
Yet, it possessed notable qualities and merits—specifically, ease of handling and a design that allowed for rapid construction—areas in which it outperformed the LeO 451. Its offensive and defensive armament were nearly identical to those of its concurrent, as were its performances. In fact, by the spring of 1940, some officials within the French Armée de l'Air were considering shifting a significant number of orders from the LeO 451 to the Amiot.
Before this, the aircraft had greatly suffered from a lack of a stable, finalized design ; throughout 1939, various Air Force evaluation committees repeatedly altered the specifications, effectively bringing progress to a standstill.
Furthermore, Félix Amiot—a private industrialist—faced immense difficulties in re-equipping his facilities with the necessary surfaces and machine tools after having his assets seized under nationalization laws - later, Amiot designed and build his own machines, there are many patents on this subject.
By the spring of 1940, however, his Cherbourg plant had completed the setup of all tooling and jigs. As the German invasion began, Amiot bombers were on the verge of rolling off the assembly line at a rapidly accelerating rate—far exceeding the production levels seen up to that point. It was too late...
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yulzari
Tech Sergeant
Indeed, and that was exactly what the Marine Nationale was intended to do had France not fallen. The removal of the French fleet from the Mediterranean was a major factor in Italy joining the Axis and the hazard of the Italians getting their hands on it was a major factor in Operation Catapault.
Shortround6
Lieutenant General
Well, if Germany is stopped at roughly the May 21st line that does leave them with Denmark, Norway, Holland and Belgium to plunder. Perhaps not worth the effort expended?
The Amiot 351 may have been a good plane. It is hard to say what it could have turned into. It's bombload was not great, 1200kg? bomb bay problem or just lack of power? Lack of power is easier to solve.
One source says that out of the 3 Amiot factories that existed, two were hit by German raids before the war stopped. Actual damage was???
Germans have a huge advantage in a strategic war against the French.
The Germans have the blind bombing system/s being set up.
The closer distances mean they are a bit more accurate.
French need lots of British help with electronics.
How much radar and radios are the French going to get for either day or night fighting?
French have some hard choices to make in the summer and fall of 1940.
Keep making existing stuff with minor improvements or gamble on switching production to better models.
Elan Vital
Airman 1st Class
- 215
- Aug 24, 2024
Some changes allegedly went on Vichy D520s to make up for speed loss due to wear or parts that couldn't be produced like in 1940, the use of the 12Y-49 engine was the most well-known and systematic change. However, while they made perfect sense in Vichy's situation, I'm not sure they would have been simply retrofitted in an undefeated France.
I rather suspect that they would be part of various packages introduced during production, for example during the switch to D523s with 12Y-51 engines or D524s with 12Z engines. Additionally, there may not have been many baseline 12Y-45 D520s left to upgrade by the time these changes would have been implemented (maybe late 1940). They may have been lost to attrition in the following months of 1940-1941.
France showed interest in British radar sets even before the war kicked off and started receiving sets slightly before the battle. It would take time to establish a system as good as in the British Isles, but it would happen. Understandably this means that the aerial battle of France would have less favourable kill ratios than in the historical BoB, with the caveat that at least some 200 German pilots (including aces like Mölders) would have been sent to Canada and would be permanently lost to the Luftwaffe. These less favourable conditions are partially compensated by the AdA adding themselves to British airpower and the British Isles being effectively undisturbed. If instead the Germans seek to strike both France and Britain (since they should hold Belgian and Dutch coasts), they will disperse their forces.
As of May/June 1940 the orders for French domestic fighters were 2205 D52X, 1000 VG 3X (including or excluding 400 Allison VG32s as firm orders?) and 400 Bloch 155s to which were added an order for 270 Bloch 155s on May 28th as the loss of the Méaulte factory making Potez 63.11s allowed G-R to produce more 14N engines instead of 14Ms. Another 250 Bloch 155s could be added depending on performance.
The Bloch were assembled at Chateauroux-Déols and Bordeaux-Mérignac, the VG 32s would be built at Clermont-Ferrand (factory online for December 1940), the Hispano VG3X at Sartrouville (first aircrafts in June 1940), the D520 at Toulouse, Tarbes-Ossun (coming online in Summer 1940, had received a first set of 50 fuselages) and a third line was to be prepared by the Chausson company with underground facilities in the Ariège region. Of these only the Sartrouville factory was particularly exposed (Parisian region).
Regarding engines, G-R types were built at Boulevard Kellerman in Paris (the latter was dismantled to be moved in June 1940 given German advance) with an associated forge shop and foundry in Gennevilliers, the shadow factories in Le Mans (assembly at Ponthierry, and one bombproof factory to be completed in August) which was being reset to produce 14Ns in July 1940, and the SNCM factory in Gennevilliers. Peugeot was also setting up 4 facilities near Bordeaux with an underground assembly base
For H-S types, current production was at Bois-Colombes and was being moved to an underground quarry on the outskirts of Paris, Fordair expected to come online in September/October 1940 (Bordeaux and Poissy, the latter being near Paris), the H-S underground factory at Jonzac (Bordeaux region), and another factory in Tarbes.
For accessories, the B-G company (spark plugs, magnetos, gyros, ignition harnesses) in Paris had a new plant near completion in the department of Gironde, Turbomeca (S-P superchargers) is presently in Billancourt in Paris but was rushing to Southern France. Aircraft weapons were generally not built in and North of Paris.
All of the factories not in Paris are to the South of the West so are not particularly vulnerable. For H-S the parisian facilities account for about 40% of the sustained production capacity to be obtained in 1941, unknown for G-R engines. However, the loss of raw material facilities in northern France reduced production by 60% in June 1940 so imports would have been necessary if France lost these facilities.
Regarding the actual frontline though, short of making an unrecognizable French Army which is much better at maneuver warfare, the main way to avoid mass encirclements and a quick defeat is to reinforce the Sedan-Monthermé sectors which were broken through OTL and/or have a mass of maneuver able to quickly counterattack in this area, so that the Germans are forced to fight a battle of attrition instead of being enable to reach the Channel (historians generally assess that this would be done by having the equivalent of the 7th Army in reserve in Champagne instead of going to Bréda, and getting a couple divisions from behind the Maginot Line).
The implication of this scenario is that the French may be able to stop the Germans and reshuffle forces over time without having to hurriedly retreat the entire Army Group 1. Optimistically the French then hold a line going from the Maginot Line to the Meuse or slighly behind it and then the Dyle in Belgium (no loss of French industry), more likely they would have to retreat back to the Escaut river in Belgium (French industries still largely safe). If they cannot block the Germans in place and have to trade space then they would likely hold a Somme-Aisne-Maginot Line where they would lose several northern raw material centers (Lille region), although they could save that region and still hold on the Somme-Aisne rivers as a repeat to WW1.
However, the French gave up on Merlin-powered D520s in November 1939 and testing of the D521 powered with this engine ceased in March 1940 as it was deemed too dangerous by its test pilot and the French focused on other projects rather than implementing the changes needed to make the aircraft work (they had not been informed of the fact the Merlin rotated inversely to the HS-12Y). They would have had to run another round of trials, while the Merlin would still be in demand for British aircrafts and possibly Amiot bombers first.
The S-P supercharger in 1939-40 was indeed more efficient than these used on the earlier Hispano engines (these lacked the difusers for the compressed air), but it was not better than the pre-Hooker's stuff (let alone when Hooker did his job in 1939-40), or not even what the Allison or DB used. At 4100m, the manifold pressure of 880 mm Hg = 34.65 in Hg = ~1.19 ata = +2.2 in psig. The G&R 14R 4 and 5, at 5000m, were pumping 1180 mm Hg = 46.45 in Hg = 1.60 ata (a tad better than the fully rated BMW 801D from late 1942 on) = ~ +8.1 psig, while being frugal due to the modern impeller and intakes thus leaving a good deal of the HP to the prop.
A 2-speed supercharger would've brought the surplus of HP down low in a greater amount than what any fancy throttle (be that the S-P system, or the Polikovsky's system the Mikulin's used) can do on a 1-speed fully-supercharged engine.
Very true.
What they give in return - the sizable increse in altitude power - was a reason why anyone with the grain of salt and industtrial might eventually went for the 2-stage superchargers.
The 12Z will not be down to 1200-1300 HP to the prop at 25-30 kft, but they will be up to
Such level of power is a feature, not a bug, and would've been useful even in 1945. For 1942-43 - if only.
Steamed_Banana
Staff Sergeant
- 1,140
- Sep 29, 2025
totally agree about the Amoit 351/54. I just forgot about it. The only caveat on that one is as Shortround6 noted, we don't have a combat history to look at. LeO 451 fought a little bit in the Battle of France but (I recently learned in some detail) was actively involved in the fighting against the British in Syria where it acquitted itself quite well. We can probably assume the Amoit would be similar though I think.
I would like to point out at this stage, during the actual Battle of France, the Armee de L'Air were relying on a total of between 700-750 fighters of the following types:
The Belgians had about 70 aircraft including 23 Fiat CR 42, 15 Gladiators, 11 Huricanes, and 30 Fairy Fox.
For bombers they had
Of these, the Leo 451, the DB-7, Breguet 693 and the Amoit 351, and (arguably) the Blenheims can be considered modern types.
Of the fighters, the 120 - 140 Hawk 75s and the 30-40 Dewoitine D.520, and the 400 Hawker Hurricanes were really the only modern types. So the French had about 20% relatively modern fighters and about 80% barely viable ones. Plus what the British sent.
And yet this collection of fighters was largely responsible for the ~800 - ~1,100 Luftwaffe aircraft shot down during the Battle of France.
Of this number, the ~ 550 MS.406 and Bloch MB 151 and (a few) 152, were not fully qualified as modern fighters (or fully developed as combat-ready designs). The MS.410 upgrade strengthens the wing for high G maneuvers, replaces the retractable belly radiator (which was prone to falling out during high G maneuvers) with a better and much simpler one, ads two machine guns, ads belt feed for the nose cannon, and increases speed about 16-20 kph. This puts it roughly on par with a Hurricane Mk 1 I'd say.
The Bloch 151 was really not ready for combat, the 152 is closer but still not quite right (especially as they were often only partly configured for the BoF). Bloch 155 has considerably better range, moves the cockpit back a bit for better view and stability, has better streamlining, ads belt fed instead of drum wing cannons plus an extra pair of machine guns, and also increases speed from about 460-480 kph for the Bloch 151 / 52 to 520 kph for the Bloch 155. Again we are (probably) approaching Hurricane Mk 1 level of viability.
If this fighter force which is increases to ~ 700 D.520 and ~ 600 Hawk 75 and ~200 -1000 VG 3X, and we upgrade the 500 x MS 406 to MS 410s, and maybe ~200 Bloch 155 replacing the 151/52s, plus maybe a few Spitfires and / or Tomahawks, then instead of 20% modern to almost modern fighters vs 80% obsolete, it's more like 60% modern vs 40% a step or two behind, I think the Germans have a much bigger problem on their hands.
I would like to point out at this stage, during the actual Battle of France, the Armee de L'Air were relying on a total of between 700-750 fighters of the following types:
- ~350 Morane M.S.406
- ~180-200 Bloch MB. 151 / 152
- ~120-140 Hawk 75 at any one time (of roughly 200-250 that were delivered to combat units during the Battle)
- ~ 30-40 Dewoitine D.520
- ~ 120-130 Potez 631
The Belgians had about 70 aircraft including 23 Fiat CR 42, 15 Gladiators, 11 Huricanes, and 30 Fairy Fox.
For bombers they had
- 50 Leo 451
- 89-90 Amoit 143
- 250-277 Bloch 210
- 200-230 Breguet 693/693
- 36 Farman F.221 / F.222
- 64 Douglas DB-7 Boston
- ~10 Amoit 351
Of these, the Leo 451, the DB-7, Breguet 693 and the Amoit 351, and (arguably) the Blenheims can be considered modern types.
Of the fighters, the 120 - 140 Hawk 75s and the 30-40 Dewoitine D.520, and the 400 Hawker Hurricanes were really the only modern types. So the French had about 20% relatively modern fighters and about 80% barely viable ones. Plus what the British sent.
And yet this collection of fighters was largely responsible for the ~800 - ~1,100 Luftwaffe aircraft shot down during the Battle of France.
Of this number, the ~ 550 MS.406 and Bloch MB 151 and (a few) 152, were not fully qualified as modern fighters (or fully developed as combat-ready designs). The MS.410 upgrade strengthens the wing for high G maneuvers, replaces the retractable belly radiator (which was prone to falling out during high G maneuvers) with a better and much simpler one, ads two machine guns, ads belt feed for the nose cannon, and increases speed about 16-20 kph. This puts it roughly on par with a Hurricane Mk 1 I'd say.
The Bloch 151 was really not ready for combat, the 152 is closer but still not quite right (especially as they were often only partly configured for the BoF). Bloch 155 has considerably better range, moves the cockpit back a bit for better view and stability, has better streamlining, ads belt fed instead of drum wing cannons plus an extra pair of machine guns, and also increases speed from about 460-480 kph for the Bloch 151 / 52 to 520 kph for the Bloch 155. Again we are (probably) approaching Hurricane Mk 1 level of viability.
If this fighter force which is increases to ~ 700 D.520 and ~ 600 Hawk 75 and ~200 -1000 VG 3X, and we upgrade the 500 x MS 406 to MS 410s, and maybe ~200 Bloch 155 replacing the 151/52s, plus maybe a few Spitfires and / or Tomahawks, then instead of 20% modern to almost modern fighters vs 80% obsolete, it's more like 60% modern vs 40% a step or two behind, I think the Germans have a much bigger problem on their hands.
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Shortround6
Lieutenant General
D.520s went through several exhaust systems during this period of time
No exhaust thrust on this one. Most show paired exhaust outlets.
how effective this was I don't know. 2nd purpose for longer exhausts was flame-dampening or less flame blinding the pilot.
With the Hispano's unequal exhaust spacing using 6 nozzles on each side would be difficult but not impossible.
Many photos of D 520 show the large 3 nozzles per side arrangement, but many photos date from the Vichy era.
I will also remind people of the weight/drag gain in the Spitfire II due not only protection but the fitting of IFF (weight of electronics and drag of early antennae).
Mk II Spit actually lost speed although climb was better with the increased power.
Exhaust thrust helps speed, climb not so much. Thrust is not power. To turn thrust into power the speed of the exhaust gas has to be a closer match to the speed of the plane.
Jet engine sitting on the runway is making a lot of thrust. It is not making much power to actually move the airplane forward. The faster the airplane moves on the runway the more power the same amount of thrust makes.
Exhaust thrust is "free" (cost is the weight of manifolds and a bit of drag).
It also works better at higher altitudes where the air is thinner, and the exhaust gasses can "escape" at significantly higher velocities.
It may be fairly easy to change Hispano 12Y production to the later model/s like the -45, -49 and -50.
Or perhaps some hybrid? Is the 1000hp at 10,700ft -50 that much better than the 920hp at 13,800ft of the -45?
-50 makes a lot more power for take-off.
The Z series makes a lot more power, but you need a lot of new machinery to make it.
All the good H-S engines in 1938-40 need Szydlowsky-Planiol supercharges and so do better G-R engines. A production bottle neck?
I will freely admit that the French can design both better airframes and better engines.
This assumes that the right choices are made and small airframes with somewhat dubius features (tail skids on 350mph fighters?) don't delay things.
It also assumes that the new prototype engines can either be made in large part on existing machinery or that adequate new machinery can be obtained (from the US?) in time.
All while the French Army is trying to build new tanks, trucks, and artillery.
No exhaust thrust on this one. Most show paired exhaust outlets.
how effective this was I don't know. 2nd purpose for longer exhausts was flame-dampening or less flame blinding the pilot.
With the Hispano's unequal exhaust spacing using 6 nozzles on each side would be difficult but not impossible.
Many photos of D 520 show the large 3 nozzles per side arrangement, but many photos date from the Vichy era.
I will also remind people of the weight/drag gain in the Spitfire II due not only protection but the fitting of IFF (weight of electronics and drag of early antennae).
Mk II Spit actually lost speed although climb was better with the increased power.
Exhaust thrust helps speed, climb not so much. Thrust is not power. To turn thrust into power the speed of the exhaust gas has to be a closer match to the speed of the plane.
Jet engine sitting on the runway is making a lot of thrust. It is not making much power to actually move the airplane forward. The faster the airplane moves on the runway the more power the same amount of thrust makes.
Exhaust thrust is "free" (cost is the weight of manifolds and a bit of drag).
It also works better at higher altitudes where the air is thinner, and the exhaust gasses can "escape" at significantly higher velocities.
It may be fairly easy to change Hispano 12Y production to the later model/s like the -45, -49 and -50.
Or perhaps some hybrid? Is the 1000hp at 10,700ft -50 that much better than the 920hp at 13,800ft of the -45?
-50 makes a lot more power for take-off.
The Z series makes a lot more power, but you need a lot of new machinery to make it.
All the good H-S engines in 1938-40 need Szydlowsky-Planiol supercharges and so do better G-R engines. A production bottle neck?
I will freely admit that the French can design both better airframes and better engines.
This assumes that the right choices are made and small airframes with somewhat dubius features (tail skids on 350mph fighters?) don't delay things.
It also assumes that the new prototype engines can either be made in large part on existing machinery or that adequate new machinery can be obtained (from the US?) in time.
All while the French Army is trying to build new tanks, trucks, and artillery.
Shortround6
Lieutenant General
Figures for the newer French stuff are all over the place.
In part because of the French system. Air Frames out the door were often far from being fully equipped. Engines/propellers/armament/instruments/radios were often not only to be supplied by the government (much the same as American and British system) but sometimes installed at government depots. There are stories of engines and propellers being taken off planes in depot and being sent back to the factory to be fitted to new airframes to be ferried to the depot/s. Then repeat. Accurate assessment of aircraft on hand is very hard.
They were supposed to have built 66 LeO 451s in 1939 and added 22, 20, 47, 64, and 111 in the five months of 1940 and 65 in June. LeO 45 production continued after the peace deal.
According to the same source France built/acquired 190 warplanes in Jan, 205 in Feb, 387 in March, 427 in April, 621 in May and 573 in June.
Actual combat worthy is way different and having both air and ground crew that can make good use of the planes is another story of it's own.
And the French need to sort out their doctrine as what was coming out of their mouths was not going well with the force they were building.
The LeO 451 was the best bomber they were building (Amoit fans can hold on, by June of 1940 there were around 6 times the number of LeO 451s as Amoit 350s) and it was about 4000lbs lighter than the He 111. Something has got to give, either bomb load or range. French ability to bomb German strategic targets (or cities) is way under what is needed.
Doctrine also governs training and tactics. If you don't train for or issue directives for close support or army support (interdiction) or escort of recon planes it doesn't matter what kinds of aircraft you have. The actual missions are going to be haphazard and very expensive for the results obtained.
All of this can be fixed (and would have been?) in 1942-43. The problem is getting through 1940 and 1941. And getting though those years in better than just survival mode.
