Advanced French Fighters vs 1942/1943 contemporaries

[tomo pauk]

there seem to have been license problems (?) with the Szydlowsky-Planiol supercharger. Or manufacturing/cost? Several models of H-S engines seem to swap back and forth.
The Szydlowsky-Planiol supercharger never caught on in the US.

Szydlowsky-Planiol supercharger offered two noticeable improvements over the run-on-the-mill superchargers of the mid-1930s:
1st was that it had a variable air intake, so there was less need for throttling to happen between SL and the rated altitude.
Second was that it impeller was good - it was of a decent size, and was efficient. Both things the contribute to the improvement of high altitude power.

However, the impellers being installed from the late 1930s on all but cancelled (or outright cancelled) the advantage of the impeller of the S-P supercharger. The S-P S/C was firmly behind the curve when the 2-stage superchargers were being manufactured, ditto vs. the the turbo S/Cs.
With the wide introduction of the 2-speed drives for the S/C, as well as the variable-speed drives, the importance of the variable air intake was all but nullified. Add the wide usage of high octane fuel and/or ADI, that pushed engine power at the low and mid altitudes through the roof via the much incresed boost, and the need for variable intake is simply not needed anymore.

 

[TM06]

Also just going back a slight bit S Shortround6 , I did some examination for French aircraft that could possibly fit the Jumo 213 and came back with a few interesting observations.
The Jumo 213E was actually quite similar in overall dimensions to the 12Z minus the weight difference.
12Z-1:

Spoiler: 12Z characteristics

Type: V-12 60° liquid-cooled, gear driven supercharged four stroke piston engine
Bore: 150mm (5.9in)
Stroke: 170mm (6.69in)
Displacement: 36.05 litres (2,199.9 cu in)
Length: 2,384mm (93.8in)
Width: 744mm (29.3in)
Height: 1,074mm (42.3in)
Dry weight: 620kg (1,367lb)

Jumo 213E:

Spoiler: 213E characteristics

Type: 12-cylinder supercharged liquid-cooled inverted Vee piston aircraft engine
Bore: 150 mm (5.906 in)
Stroke: 165 mm (6.496 in)
Displacement: 35 L (2,135.2 in³)
Length: 2,266 mm (89.2 in)
Width: 777 mm (30.6 in)
Height: 980 mm (38.6 in)
Dry weight: 1040 kg (2,072 lb)

So theoretically speaking, it might be actually quite easy to install the 213 into more than a few aircraft with some modifications. Immediately the VB.10 springs to mind as that thing was already huge and definitely had the strength to carry those engines. Another would be the SE.580 since that was going to use an enormous Hispano-Suiza 24Z engine and had the strength to support it. The Br.482 also likely wouldn't mind the power hike.
Single-engined fighters get a bit trickier, but the SE.520Z, M.520T and D.554 would likely be able to handle it with their strengthened frames and stronger wings. I have my doubts about the base VG.39 carrying it, but the VG.60 is notable for being designed with the engine in mind. I'd probably rule out the Morane Saulners and probably the SNCAO 200 from carrying it as well.
The MB.157 is also notable as it likely could fit the engine, but I think it'd be more likely that it would stick with the 14R. A Jumo 213 MB.157 would certainly be a monster however.

• Edit: Apparently the VB.10 with two Jumo 213's was actually a thing, it was called the VB.15. Image linked below.

 

[Shortround6]

So theoretically speaking, it might be actually quite easy to install the 213 into more than a few aircraft with some modifications.

Single-engined fighters get a bit trickier, but the SE.520Z, M.520T and D.554 would likely be able to handle it with their strengthened frames and stronger wings.

The Problem isn't the physical size of the engines (all of the V-12 engines from 33.9 liters to 36.7 liters, DB 601 to Griffon are within a few inches of each other in any dimension).
The Problem as your figures show, is the 300-400kg weight difference. In small fighters that screws up the center of gravity. and the knock on effect. You can't use a propeller that works on a 1000-1100hp engine on a 1500-1800hp engine. The Bigger engine needs a bigger radiator and oil cooler. The Big prop goes on the front of the plane (weirdos aside) the furthest to the front from the CG. The radiators and oil coolers can be moved to help balance the plane. Spitfires had the radiators a bit behind the CG as did some other aircraft. The P-40F actually used around 35 gals of fuel in the behind the seat tank was used to counterbalance the weight of the two speed, single stage Merlin engine. The P-40 was not huge but was substantially bigger than any French fighter except the MB 157. That was to balance the under 100kg difference between the Allison and Merlin engines.

The Spitfire itself was a real balancing act. There were balancing weights in the nose of the early ones that had the 2 blade wooden propellers, Most of the weights came out of the planes with the 3 blade variable pitch/constant speed props. By the time you get to the MK IX there were five 17.5lb weights in the tail (or adjusted for individual aircraft?)
" Ballast consisting of 5 x 17.5 lb. standard weights is permanently fitted on a bar situated in the fuselage adjacent to the tail wheel."
I don't have a weight breakdown of the Griffon engine versions. The Griffon was the 36.7 liter engine. Certain parts needed to be stronger, but the plane had to balance much the same as the MK IX. 4.4 to 4.8 inched from the datum line as the fuel and ammo was used.

http://www.spitfireperformance.com/ab197datum.gif

You can move radios around and you can move oxygen tanks around, you can put in some armor (heavier seat armor vs steel balance weight doing nothing? )
with bigger airplanes you have more choices of were to put things.
The 109 ran into a lot of problems. On the later, heavier ones, they couldn't fit the tires that would hold the weight in the wing, leading to a number of bumps or bulges over the wheel wheels.

For the French I really wonder how long that retracting tail skid on the D.550 would have lasted for service planes
Or how well the landing gear in general would have stood up to service conditions with combat loads.

 

[TM06]

The Problem isn't the physical size of the engines (all of the V-12 engines from 33.9 liters to 36.7 liters, DB 601 to Griffon are within a few inches of each other in any dimension).
The Problem as your figures show, is the 300-400kg weight difference. In small fighters that screws up the center of gravity. and the knock on effect. You can't use a propeller that works on a 1000-1100hp engine on a 1500-1800hp engine. The Bigger engine needs a bigger radiator and oil cooler. The Big prop goes on the front of the plane (weirdos aside) the furthest to the front from the CG. The radiators and oil coolers can be moved to help balance the plane. Spitfires had the radiators a bit behind the CG as did some other aircraft. The P-40F actually used around 35 gals of fuel in the behind the seat tank was used to counterbalance the weight of the two speed, single stage Merlin engine. The P-40 was not huge but was substantially bigger than any French fighter except the MB 157. That was to balance the under 100kg difference between the Allison and Merlin engines.

The Spitfire itself was a real balancing act. There were balancing weights in the nose of the early ones that had the 2 blade wooden propellers, Most of the weights came out of the planes with the 3 blade variable pitch/constant speed props. By the time you get to the MK IX there were five 17.5lb weights in the tail (or adjusted for individual aircraft?)
" Ballast consisting of 5 x 17.5 lb. standard weights is permanently fitted on a bar situated in the fuselage adjacent to the tail wheel."
I don't have a weight breakdown of the Griffon engine versions. The Griffon was the 36.7 liter engine. Certain parts needed to be stronger, but the plane had to balance much the same as the MK IX. 4.4 to 4.8 inched from the datum line as the fuel and ammo was used.

http://www.spitfireperformance.com/ab197datum.gif

You can move radios around and you can move oxygen tanks around, you can put in some armor (heavier seat armor vs steel balance weight doing nothing? )
with bigger airplanes you have more choices of were to put things.
The 109 ran into a lot of problems. On the later, heavier ones, they couldn't fit the tires that would hold the weight in the wing, leading to a number of bumps or bulges over the wheel wheels.

So for weight reasons, we're limited to only the larger aircraft, the 157 and possibly the M.520T. Shame really, I'd love to see more Jumo 213 fighters.
That does still give us a few platforms for the engine however.

• VB.10 (Can fit it)
• VB.20 (Designed for the engine)
• VG.50 (There's multiple VG.50's, I'm referring to the bomber in this case)
• VG.60 (Designed for the engine)
• SE.580 (Definitely can fit it)
• SE.100 (Maybe?)
• SE.500 (Also a maybe)
• CAPRA R.40
• Br.482
• MB.162
• LeO 45, NC.150 and Amiot 354

For the French I really wonder how long that retracting tail skid on the D.550 would have lasted for service planes

They probably wouldn't keep it on the production models...is what I want to say. The VG.33C1 and MB.152C1 both made it to production with tail skids, so there's a nonzero chance that the first production D.551's get it as well. I doubt they'd keep it for very long however as the SE.520Z and M.520T both had retractable tail wheels.

 

[Shortround6]

Title
Advanced-French-Fighters-vs-1942-1943-contemporaries.

France does not have access to the Jumo 213 in 1942-1943.
Germany didn't even have access to air worthy Jumo 213s for much of 1942.

Any plans for French fighters or other aircraft powered by Jumo 213 engines would have to be as an ally of Germany (forced, or otherwise) with design work starting in 1940-41 or post war (1945 or after).

The French had a lot of strange ideas for aircraft. Other countries had some strange ideas (fewer than the French), except for the US. But the size of the US aero-industry allowed for a number of strange ideas without derailing the conventional planes that actually fought the war. We can sometimes look at non-French aircraft that actually flew to see what some of the problems were.
The fact that counter rotating prop was made to work in 1945-47 for service use doesn't mean it wasn't thought of earlier. It just took that long to get it to actually work. Both to actually improve performance and to not have mechanical problems leading to loosing the aircraft. Figuring out the prop pitch of the 2nd prop at different speeds took a while. There may have been vibration problems. 2nd prop operating in disturbed air. Vibration may have changed at different rpms of the prop or altitudes or............

SE.580 (Definitely can fit it)

model
Rear vision sucks, Bailing out may be problem. It was also designed with expectation that it would have 3600hp and 2500 liters of fuel (more than the P-47N).

Maybe the US should have not played with some of their ideas.

XP-69 Wright R-2180 Tornado 42 cylinder engine.
Maybe Republic could have spared a couple of men to work on drop tanks

Republic XP-72 with contra-rotating propeller. Accounts differ as to if gave any better performance, or equaled the 4 blade prop used.
The XP-72 with the C-R prop first flew on 26 June 1944. An order had been placed for 100 of them but the order was canceled Jan 4th 1945.
Republic had been working on the P-84 Jet in 1944.

 

[TM06]

Title
Advanced-French-Fighters-vs-1942-1943-contemporaries.

France does not have access to the Jumo 213 in 1942-1943.
Germany didn't even have access to air worthy Jumo 213s for much of 1942.

Any plans for French fighters or other aircraft powered by Jumo 213 engines would have to be as an ally of Germany (forced, or otherwise) with design work starting in 1940-41 or post war (1945 or after).

The French had a lot of strange ideas for aircraft. Other countries had some strange ideas (fewer than the French), except for the US. But the size of the US aero-industry allowed for a number of strange ideas without derailing the conventional planes that actually fought the war. We can sometimes look at non-French aircraft that actually flew to see what some of the problems were.
The fact that counter rotating prop was made to work in 1945-47 for service use doesn't mean it wasn't thought of earlier. It just took that long to get it to actually work. Both to actually improve performance and to not have mechanical problems leading to loosing the aircraft. Figuring out the prop pitch of the 2nd prop at different speeds took a while. There may have been vibration problems. 2nd prop operating in disturbed air. Vibration may have changed at different rpms of the prop or altitudes or............

SE.580 (Definitely can fit it)
View attachment 781149
model
Rear vision sucks, Bailing out may be problem. It was also designed with expectation that it would have 3600hp and 2500 liters of fuel (more than the P-47N)

The Jumo 213 likely wouldn't be available until after the time-frame yes. Maaaaaaaaaaaybe late 1943 if Arsenal can set up production quickly. The 213 was more of an "and also" to this secondary theoretical as a sort of wildcard engine choice to throw into the discussion.
It is worth noting however that a majority of these designs did start their planning phases in 1940, most of them just weren't able to be completed until post-war.

I should mention that the SE.580 is an interesting case because it was based on the D.520's airframe. The cowling is definitely the worst part of it, but the basic design is quite solid. A lighter version using the 213 instead of the 24Z / 24H has potential, as the cowling would be deleted drastically improving the aerodynamics. If they wanted to keep a lot of that fuel, it could be a sort of French Mustang - a long ranged single-engine escort fighter. However that would definitely be a 1944 development, therefore out of the scope of this discussion. Even if it failed, there's aspects of the SE.580 that might be able to worm their way into the D.520/D.55x frames due to the latter's airframe being based on the former's - particularly the wings, cockpit and tail structure.

Propellers I think are largely fine on the French side, both the Ratier and Chauvière 3-bladed props were quite excellent and there was a very good 4-bladed paddle design from Chauvière fitted to the Blériot 110. Given their design philosophy, most French fighter aircraft would likely be fitted with high-efficiency 3-bladed props throughout the war similar to Germany.

 

[Shortround6]

I should mention that the SE.580 is an interesting case because it was based on the D.520's airframe.

Only in general shape and if you squint really, really hard.
Kind of like saying a DH Mosquito was based on a DH Dragon Rapide. Both twins, both made out of wood and the tails look kind of the same.
Maybe they planned to use the same navigation lights in the wing tips on the SE.580 as the D 520?

Sud-Est (SNCASE) SE 580 Fighter

Designed around a 24-cylinder engine, the French Sud-Est SE 580 fighter was one of the last piston engine fighters constructed; the jet age would leave the project unfinished.

oldmachinepress.com

The cowling is definitely the worst part of it, but the basic design is quite solid. A lighter version using the 213 instead of the 24Z / 24H has potential, as the cowling would be deleted drastically improving the aerodynamics.

The Jumo 213 version was the 3rd powerplant configuration. The first had been like the VB. 10 with one engine behind the cockpit and one in front (how much of the D.520 was left at that point? the Cowl?

If they wanted to keep a lot of that fuel, it could be a sort of French Mustang - a long ranged single-engine escort fighter.

Fuel is for the 2nd version using the H-S 24Z engine of 24 cylinder H configuration.

Even if it failed, there's aspects of the SE.580 that might be able to worm their way into the D.520/D.55x frames due to the latter's airframe being based on the former's - particularly the wings, cockpit and tail structure.

About zero chance.

The D.520/D.55X was about the size of a 109. The SE.580 was the size/weight of a P-47. It was actually planned to be about 10% heavier empty than a P-47D-25.
Somebody wants to put a bubble canopy on a D.520 be my guest, but few, if any parts aside from screws or rivets would be used between the two airframes in the wings, cockpit and tail.

For props, the French 3 blade ones may have been just fine, they may have done fine with 4 bladed props. The problem was with the contra-rotating props, from anybody. A lot of designs around the world during WW II, if not before.
Actual squadron use didn't happen for one-two years after the war. The "theory" said they would get better performance and less (no?) torque effect. Actual practice took a while to short out.
Edit.
Bell, always truthful about what they could deliver (sarcasm) had proposed the XP-52 in 1939 or 1940.

Contract was canceled in late 1940. There were designers planning on using contra-rotating props in 1940 for use in 1942? Didn't happen.

 

[TM06]

Only in general shape and if you squint really, really hard.
Kind of like saying a DH Mosquito was based on a DH Dragon Rapide. Both twins, both made out of wood and the tails look kind of the same.
Maybe they planned to use the same navigation lights in the wing tips on the SE.580 as the D 520?

The Jumo 213 version was the 3rd powerplant configuration. The first had been like the VB. 10 with one engine behind the cockpit and one in front (how much of the D.520 was left at that point? the Cowl?

Almost everything I could find about the SE.580 stated that it was a derivative of the D.520, and looking at their blueprints side-by-side show a number of similarities.

Also I don't think I used the right word when I said cowling, I mean the air intake behind the cockpit.
The base Jumo 213 was one of the potential options for the naval version, the SE.582, but the base SE.580 seems to have only two options in the Hispano-Suiza 24Z and the Arsenal 24H.

For props, the French 3 blade ones may have been just fine, they may have done fine with 4 bladed props. The problem was with the contra-rotating props, from anybody. A lot of designs around the world during WW II, if not before.
Actual squadron use didn't happen for one-two years after the war. The "theory" said they would get better performance and less (no?) torque effect. Actual practice took a while to short out.

Ah, must've misread what you said prior. I'm not very familiar with the ramifications of a contra-prop arrangement beyond complexity.

 

[Shortround6]

Almost everything I could find about the SE.580 stated that it was a derivative of the D.520, and looking at their blueprints side-by-side show a number of similarities.

D.520 was 28ft 8 in Plus or minus an inch (2.5cm) or so.
SE.580 was 42ft 8in Plus or minus an inch (2.5cm) or so.

Basically the SE.580 was about 50% longer in the fuselage.
Scale the SE.580drawing up, everything is going to get bigger, the forward engine cowl (has to got over that H engine) and the vertical fin and rudder are going to be huge.
Might have changed a bit with the use of the Arsenal 24H engine.

" stated that it was a derivative of the D.520"

Unfortunately that phrase or word derivative gets used a lot in articles/books. Sometimes it means that the same design team worked on both planes and would similar shapes (like vertical stabilizers and rudders that had worked (not given problems) on the earlier aircraft but scaled up or down to suit the size of the new aircraft.
A lot of times it does NOT mean you can take the early airframe and with some modifications use it as a flying prototype for the new plane.

Sometimes it means, like the Grumman F4F and F6F, that they wanted some of the same features (view over the nose, handling qualities, stall qualities, etc and the carrier qualities, arrested landing impact limits) but try to find any common parts between the two? They did not use the F4F wing with and center section joining the old wing parts.

Sometimes it does mean that they used common parts, like the Hawker Henley bomber used the outer wings of the Hurricane on a new center section.

Unfortunately the authors often do not state what differences were or what old parts were used, if any.

In the case of the D.520 at just under 6000lbs and the SE.580 at 17,900lbs any (most?) structural parts that were rated at 12 Gs (ultimate load, 8 Gs service if the French used the same formula the US did) in the D.520 the same parts (wing panel?) would be rated at 4 Gs (ultimate load, 2.66 Gs service).

 

[TM06]

D.520 was 28ft 8 in Plus or minus an inch (2.5cm) or so.
SE.580 was 42ft 8in Plus or minus an inch (2.5cm) or so.

Basically the SE.580 was about 50% longer in the fuselage.
Scale the SE.580drawing up, everything is going to get bigger, the forward engine cowl (has to got over that H engine) and the vertical fin and rudder are going to be huge.
Might have changed a bit with the use of the Arsenal 24H engine.

Didn't know it was that big of a difference, my bad again. I was having trouble finding specifications for it so I assumed that they'd be relatively similar in size - compounded by the SE.580 being titled a derivative of the D.520 nudging me further in that direction. It's odd, I rarely make mistakes like that in the realms of space and the sciences. But I guess my lack of experience and knowledge about the various isms that make an aircraft are causing me to jump to conclusions.

 

[TM06]

Getting back on topic, I've actually discovered a proper multi-role fighter candidate for France around this time period: the Roussel R.30.
It was quite small but its performance was quite good (520 kmh / 323 mph, 8 minutes to 5,000 m) and could carry a 250 kg bomb under the fuselage along with a forward armament of 2 x 20 mm Oerlikon AS cannons. Being the only French fighter in the C1 programme that could fit a reasonably sized bomb, it seems like a decent choice. They also planned to fit an 800 hp engine in place of the 690 hp engine, so it does have development potential.

 

[Shortround6]

The French had a fetish for small, toy like, aircraft and this is one of the prime examples.

• Length: 6.10 m (20 ft 0 in)
• Wingspan: 7.72 m (25 ft 4 in)
• Height: 2.10 m (6 ft 11 in)
• Wing area: 10 m2 (110 sq ft)
• Empty weight: 1,030 kg (2,271 lb)
• Max takeoff weight: 1,768 kg (3,898 lb)

One wonders were they got the ex circus midgets to act as ground crew in the Photo.
This thing is smaller than some acrobatic aircraft. Like a Mudry Cap 10.
Or it shows the genius of the French designer. Even if we take 250kg of the max weight we still have a useful load of 488kg.
The Hawk 75s in French service had a useful load of 550kg, in plane that weighed 2587-2613kg (depending on version)
Bloch 152 had a useful load of 535kg out of a 2,693 kg gross.
The Caudron C.714 had a useful load of 485kg out of a 1880kg plane (no bomb). Granted the Caudron had a lower power engine but the engine was only 20kg heavier.

If something sounds to good to be true, it probably is too good to be true.
Useful load includes things like Pilot, radio/s, oil, guns/ammo, and the fuel. Hawks had 398 liters of fuel at the weight given.

 

[Shortround6]

The French built 4 of these small fighters, sort of like 7/10s to 8/10s scale fighters.

The Bloch MB 700 with G-R 14M engine
The Caudron Series 714, 760, 770 with 3 different engines.
The Potez 230 with H-S 12X engine
The Roussel 30 with G-R 14M engine.

Only the single Caudron 770 went much over 4000lbs and none use a wing bigger than 135 sq ft.

We can argue (and probably will) how useful they would have been in 1940, had France actually managed to get them into production (the Caudron 714 wasn't very useful).

But in 1942-43 they defiantly would not have been very useful without major redesign/changes. Their small size limited growth too much. The entire concept was flawed. Yes the airframe was cheap and the engines were cheaper than bigger engines. But,
The Constant speed props, while not full price, were not a lot cheaper.
The instrument panel was not any cheaper
The radio/s were not any cheaper.
The guns/gun sight is not any cheaper (unless you use less of them).
The pilots flying them are not cheaper to train.

In 1940-41 with increased demands for pilot and fuel protection you cannot use thinner or smaller plates for the Pilots unless you can recruit really small pilots. So improved cockpit protection is the same size/weight as for a larger fighter. Fuel protection depends on method but good protection becomes a higher percentage of the weight of the aircraft. To pull numbers out of the hat, 200lbs of protection on a 4000lb gross plane is 5%, even 220lbs on a 6,000lb plane is 3.66%

A number of these planes were fast, but most did not climb well. The small wings mean landing speeds are high or certainly not lower than the larger bigger wing planes and that is before you put in the armor and tank protection. Most are going to have a wing loading very close the 109E. Who knows what the roll is like but none of these have slats (?) to maybe help with turn. and the power to weight is lower than most average 5500-6500lb fighters of 1940. In 1942 you are depending on power increases that never came. They were unlikely to come, or increase enough. Assuming you can get the H-S 14M engine up to 800hp that is a 14% increase. The DB 601E was giving around 29-30% more power than the DB601A at altitude.
There was no real alterative to the R-G 14M engine. Trying to stick a bigger engine in the planes calls for a lot redesign. The Renault 12R had hit the end of it's road. (think of a DH Gipsy 12).
Swiping H-S 12Y engines to stick in the Potez 230 just means you don't have H-S 12Y (or 12Z) engines to stick in DW 520s or 55X or ????

Basically a few too many people at the French Air Ministry had too many long lunches at the area cafe's and didn't squash this whole plan when they should have.

 

[TM06]

- light fighter discussion -

Light Fighters in general are a sort of dead-end. Even the best light fighter - the Zero - was entirely obsolete by 1942. Unfortunately, the great Colin Chapman's quote of "Simplify, then add lightness" very rarely applies to aircraft. The ideal weight range for a piston fighter seems to be in the 2,500 kg ~ 4,500 kg range, anything lower than 2,000 kg becomes a headache.

However the R.30 is an interesting case because it was based around the M.B.151's design (I believe the designer was a relative of the guy who designed the M.B.152). So although it's not a 1:1 comparison, we can glean some ideas on what the Bloch's could've been capable of in regards to multi-role and strike capabilities. I think a bomb layout of 3 x 250 kg bombs (one under each wing, one centrally) is reasonable for the 155 and 157. Maybe 2 x 500 kg bombs (one under each wing) for the 157 if I'm being generous.

One wonders were they got the ex circus midgets to act as ground crew in the Photo.

Something that's worth mentioning, and might have interesting repercussions regarding the size and weight of French designs, is that France is consistently on the lower end of the average height chart from 1930 to 1940 regarding the major players in the war in this time period. 169 cm / 5'5" to 171 cm / 5'6", roughly equal with Italy and only slightly taller than Russia. You know who else had small aircraft designs in this time period? Italy and Russia.

Or it shows the genius of the French designer.

If I can be 100% honest for a moment, I do believe there's truth in this statement. Let me explain.
France has been a front-runner and pioneer in military equipment and theory for a long time, and to an extent they still are.

- The first smokeless powder cartridge made and adopted for military service was the 8 mm Lebel - a French round for a French weapon adopted by France.
- The French Canon de 75 modèle 1897 was one of the best artillery pieces from its introduction all the way until the early 30's, along with setting the template of what any and all future mobile artillery pieces would be. A version of it even ended up as the main gun for the M4 Sherman.
- A contender for the first assault rifle is the Ribeyrolles 1918, a very capable weapon that almost certainly would've been mass-produced had WW1 not ended.
- The Renault FT was the first mass-produced tank, was exported in various forms to over 30 countries world-wide, and also set the template for the configuration of almost all tanks including modern ones.
- A strong contender for best aircraft of WW1 is the SPAD S.XIII, a highly reliable and incredibly tough fighter whose only real competition is the better performing but less reliable Fokker D.VII.
- The French 7.5 mm MAS cartridge is an excellent round despite its small size, having ballistics comparable to modern 7.62 NATO. A marksman and competitive shooter acquaintance of mine called it the best round he's ever fired.
- The MAS-36 carbine was average in terms of accuracy (not a bad thing) but was immensely strong and reliable.
- The SOMUA S.35 was arguably the best tank in the world in 1940.
- France had one of the strongest navies in the world in 1940, only beneath US, Britain and Japan in that order, with the scuttling of the French Navy being a significant strategic blow to the Allies. Even in modern times, the French Navy is comfortably the second or third strongest navy in the world - behind US and tied with Britain.
- While the Maginot Line is often ridiculed for its perceived ineffectiveness, it's telling that Germany made the choice to trek through what many considered a militarily untraversable forest just to avoid the defenses. Had they took the line head-on, it would've been a bloodbath.

There's many more examples I could give but we'd be here all day. France was - and still is - a world leader in the military realm. The speed at which Germany took down France was a shock to the world, something absolutely nobody expected. They had the resources, industrial base, equipment, designers and engineers to compete with Germany, with a vast majority of military theorists world-wide at the time believing that WW2 would be extremely similar to the trench-based WW1. Germany just flipped the script, again in a way that nobody expected.
So while your skepticism and cynicism is entirely understandable, especially considering the bureaucratic mess that France was in from 1936~1940, I do think that you're not quite giving them the credit they deserve.

 

[Shortround6]

The ideal weight range for a piston fighter seems to be in the 2,500 kg ~ 4,500 kg range, anything lower than 2,000 kg becomes a headache.

In large part this is because there is a certain amount of fixed payload. By that I mean the pilot, cockpit (including instruments, controls, seat etc) usually the radio. Which cannot be made smaller than a certain size and still fit in the pilot. Pilot includes parachute and flying suit (cold weather) and possibly life vest/raft. The smaller/lighter a fighter is the larger percentage of the total that section of weight becomes.

However the R.30 is an interesting case because it was based around the M.B.152's platform

There is no way under Newton (physics) that the R.30 based on the M.B. 152 platform. That is if we mean that it used any parts from the M.B. 152. It kind of looks like a M.B 152 but that is about as far as it goes. That or all the specifications/dimensions published in English language articles books are wrong (could be more than just possible).
The thing about fighter bombers is that they not only have to get off the runway with the proposed load, they have to make it to the target (certain amount of fuel) and they cannot be total sitting ducks while doing it. They are never, ever, going to blitz by defending fighters without escort but they need to be going fast enough to still get into the fight after they drop their bombs even if many miles short of the intended target.
The Hurricane became a famous ground pounder, however it some times carried one bomb and one drop tank because it could not reach the targets on internal fuel, French could resort to this. While it could carry two 500lb bombs it often carried two 250lbs bombs because the 500lb bombs impacted performance too much.
P-40s were also quite famous attack aircraft. By 1943 they could, in theory, carry two 1000lb bombs and one 500lb bomb. What seems to be a mystery is how long a runway they needed. There is some information on using ferry tanks on a P-40N, 2500ft needed for a single 170 US gal ferry tank. That is ground run, not counting clearing the trees. This model was plumbed for under wing tanks, two 170 US gal tanks required 3800 ft of runway. Ferry flights were usually done without ammo and sometimes done without guns. Large loads could be carried but often there were severe restrictions placed on flight maneuvers. Both the Hurricane and P-40 had substantially large wings than the MB 152/155.

If I can be 100% honest for a moment, I do believe there's truth in this statement. Let me explain.
France has been a frontrunner and pioneer in military equipment and theory for a long time, and to an extent they still are.

Yes and no. They often pioneered some developments and then sat on their hands and thought nobody else could copy them or went off on some crazy tangent for years to the detriment of not only the French forces but sometimes to their allies.

- The first smokeless powder cartridge made and adopted for military service was the 8 mm Lebel - a French round for a French weapon adopted by France.

True, but when you are first you often have to be the first to change/update because everybody else doesn't just copy you, they try to improve things. The 8mm Lebel should have been replaced in 1898-1900.

- The French Canon de 75 modèle 1897 was one of the best artillery pieces from its introduction all the way until the early 30's, along with setting the template of what any and all future mobile artillery pieces would be. A version of it even ended up as the main gun for the M4 Sherman.

The gun itself was pretty good, but by 1918 the carriage was obsolete. By the 1930s it was a travesty, only kept because there was no money to replace it. There was also no money to replace it in many of the other countries that had adopted it. This were the French went off on one of their crazy tangents with their enthusiasm for the "75" and thought the "75" could replace all (or most) of the Army's field artillery, like howitzers. The Americans bought into this and in WW I thought that the French had the answer to most things related to the army. By 1917-18 the French were digging themselves out of this hole but then came peace and with thousands of French "75s" littering the landscape (and artillery parks) in many nations the Life of the French "75" continued for several more decades.
The French "75" helped set back indirect artillery fire and improved artillery tactics/doctrine for years.

- The Renault FT was the first mass-produced tank, was exported in various forms to over 30 countries world-wide, and also set the template for the configuration of almost all tanks including modern ones.

Well, there are only so many ways you can lay out a tank.

- The French 7.5 mm MAS cartridge is an excellent round despite its small size, having ballistics comparable to modern 7.62 NATO. A marksman and competitive shooter acquantaince of mine called it the best round he's ever fired.

This is not at all true. I personally invented the best round in the world
OK not true, in the early 90s I copied what some other people had done in 1950s and necked a 7.62 nato (.308) down to 6.5mm and beat the crap out of most people with 7.62 NATO (.308) rifles.
The 7.5mm MAS cartridge may be a decent cartridge but there is nothing amazing about it. It is slightly larger than the 7.62 nato (enough to win bar bets) but you need a good dial caliper and a good scale to find the differences. The French were pretty much playing catch up in the 1920s to where other peaple already were.

- The MAS-36 carbine was average in terms of accuracy (not a bad thing) but was immensely strong and reliable.

Well, it should be. If you can't make a strong and reliable rifle in the late 1930s using new machinery you should just give up and stop making rifles.
French did not trust their soldiers to not muck things up taking them apart. Special tools were needed to take the wooden hand guards off the barrels.
This is something of a flaw. Or an indication that troops were not trained to sight in their own rifles.

- The SOMUA S.35 was arguably the best tank in the world in 1940.

Man, you are going to get a lot of arguments on that one.
Lets see.
Design 3 man tank instead of 2 man tank. CHECK.
Put 3rd man in hull where he can't see much of anything????
Keep one man in the turret so he performs all the tasks the "turret man" (commander?) on a two man tank has to do.?????
Granted the German MK II pulled the same trick.
Building a nearly 20 ton tank and keeping the one man turret was a major Faux Pas

 

[Shortround6]

Forgot the Lebel rifle.
Good for it's time (1886) but keeping the tube feed under the barrel after about 1890 was probably a mistake.
The Berthier Carbine of 1890 was OK but the ordering of a rifle version in 1907 should have been grounds for execution for treason.

 

[TM06]

There is no way under Newton (physics) that the R.30 based on the M.B. 152 platform. That is if we mean that it used any parts from the M.B. 152. It kind of looks like a M.B 152 but that is about as far as it goes. That or all the specifications/dimensions published in English language articles books are wrong (could be more than just possible).

Probably used the wrong word when I said platform there. What I mean is that the Bloch's design was the basis for the Roussel's design rather than any commonality of parts. Also I got the model wrong, it was the M.B.151 and not the M.B.152 that the R.30 was designed after. My mistake.

Well, there are only so many ways you can lay out a tank.

The British heavies, A7V, Tsar Tank, CLB 75, Saint-Chamond, Schneider CA1, Whippet, and almost every other non-turreted tank would disagree. I think it's fair to give props to the FT on this one.

Man, you are going to get a lot of arguments on that one.
Lets see.
Design 3 man tank instead of 2 man tank. CHECK.
Put 3rd man in hull where he can't see much of anything????
Keep one man in the turret so he performs all the tasks the "turret man" (commander?) on a two man tank has to do.?????
Granted the German MK II pulled the same trick.
Building a nearly 20 ton tank and keeping the one man turret was a major Faux Pas

I'm used to getting arguments relating to the S.35, but my position is that it was the best individual tank in service at the time. It was weaker in the soft factors than its German counterparts (aside from the Panzer II), but it was very strong in the hard factors. The gun was quite good for its calibre, the armour was quite thick and resilliant for a tank of its weight, its mobility was solid and it could climb very well.
I don't claim that it was the perfect vehicle or the end-all-be-all of armoured warfare, but if you were to put a S.35 head-to-head versus almost any other tank in service at this time, it would have a very good chance of winning.
The S.40 was going to alleviate the turret issues with a 2-man ARL 2C turret then a later 3-man design by FCM fitted with the very good SA 37 gun, but the Fall prevented that from happening. It was more of a stop-gap measure until the winner of the G1 programme could come online (which would've happened earlier if Louis Renault wasn't an absolute jobber).

 

[Shortround6]

I don't claim that it was the perfect vehicle or the end-all-be-all of armoured warfare, but if you were to put a S.35 head-to-head versus almost any other tank in service at this time, it would have a very good chance of winning.

Trouble is it was not head to head, one on one. It was 3 or 5 or 10 vs 3 or 5 or 10. The German (and British) multi man turrets allowed for better co-operation of the crews and better co-operation between tanks in a platoon or company. Also use of radios. Planning to fit radios is sort of miss in combat.
The British had one tank in France that was better and a few more that were close. The 2pdr was a very good gun (let down by sight system) and with there man crews a very good rate of fire. With the commander commanding the tank and not playing gunner, situational awareness could be much higher (if training/experience allowed).
Soviet tanks (T-26 and BT-7s) had as powerful a gun as the S.35, crappy armor, very good mobility with the BT tanks. Turret was iffy. Commander was the gunner but at least he didn't have to load. Vision was crappy.
It is a lot of this 'soft' squishy stuff that makes a big difference.

The gun was quite good for its calibre, the armour was quite thick and resilliant for a tank of its weight, its mobility was solid and it could climb very well.

Good gun, lousy rate of fire and even worse rate of engagement. Rate engagement is how fast a tank/crew could knock out one tank and the spot another, align the gun/turret with a 2nd target and fire at/destroy the 2nd target. This can differ significantly from the rate of fire which is throwing rounds into the breech of gun that remains pointed in one direction/elevation. Practical rate of fire is also different than 'test' rate of fire. Test rate of fire can have the ammo stowed conveniently near the guns breech.

The S.40 was going to alleviate the turret issues with a 2-man ARL 2C turret then a later 3-man design by FCM fitted with the very good SA 37 gun, but the Fall prevented that from happening.

Coulda/shoulda.
Germans were working on the 50mm/42 gun for the MK III tanks. First left the factory in July 1940. Production may have taken a while to fully swap over.
Germans coulda/shoulda fitted the 50mm/60 and skipped the 50mm/42.
On the other hand, if France did not fall in June or July/Aug of 1940 existing MK IIIs could have been up gunned if gun production allowed. A lot easier that trying to put a new turret on a tank.
France built how many thousands of 1 man turret tanks during the 1930s?
FT 17s can be excused.

 

[tomo pauk]

French did not trust their soldiers to not muck things up taking them apart. Special tools were needed to take the wooden hand guards off the barrels.
This is something of a flaw. Or an indication that troops were not trained to sight in their own rifles.

Soldiers sighting their own rifles was not a thing on this side of the pond.

 

[TM06]

Coulda/shoulda.

Rather than being a matter of could have, it's a matter of was going to. The S40 prototype was fitted immediately with the ARL 2C turret, you can even very clearly see the difference in turret design in the image below. The FCM turret was a later development in 1941 that got canned in 1942 due to Operation Torch and the subsequent Case Anton.

France built how many thousands of 1 man turret tanks during the 1930s?
FT 17s can be excused.

Not counting prototypes or wheeled vehicles like the AMD.35 and Panhard 178:
AMC 34 (12 built)
AMR 33 (123 built)
AMR 35 (167 built)
FCM 36 (100 built)
Hotchkiss H35 and H39 (±1,200 built)
Renault R35 (1,540 built)
Renault R40 (~145 built)
Char D1 (160 built)
Char D2 (100 built)
SOMUA S35 (~440 built)
Char B1 / B1 Bis (403 built not counting the two B1 Ter prototypes)
Which tallies up to a grand total of 4,390 tanks with one-man turrets. While I'm willing to excuse a lot of the smaller tanks for having one-man turrets due to their size, the B1 had no reason not have at least a two-man turret. But then again, it was designed all the way back in 1921 - hot off the heels of WW1.
It is worth noting almost all of the G1 programme entries had two-man turrets, and they were going to use the 5.7 tonne ARL 3 two-man turret with a turret basket based on the smaller turret on the FCM F1 once they swapped over to the 75 mm for the main gun.