yulzari
Tech Sergeant
I am one of the 96% of the world who do believe in metric.
Advanced French Fighters vs 1942/1943 contemporaries (14 Viewers)
SaparotRob
Unter Gemeine Geschwader Murmeltier XIII
That's about 39 bushels of a wey.
yulzari
Tech Sergeant
I was brought up on pecks, chains, apothecary drachms and ells.Not to mention knowing that there are 1,008 farthings to the guinea and my pocket money was half a crown. So am bilingual but speak and dream in metric.
But enough of this matter. I am off to treat myself to a large Janner's handbag washed down with Black Rat Perry and a pint of Slack-Ma-Girdle for the Memsahib.
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MiTasol
Major
Any chance of a translation for us who are not bilingual?
MiTasol
Major
I too was bought up on inFerial (now called American in computing) measurements but have been using metric since the tail end of the 50's when my school started teaching metric. It is so much easier and more logical than measuring in 128ths or 256ths and having multiple gallons and ounces and miles and so many other measurements that have the same names but different values.
SaparotRob
Unter Gemeine Geschwader Murmeltier XIII
Full Disclosure: I'm an immigrant now and I use metric. Mostly as some sort of punchline.
As my surname is Slack, I too would appreciate a translation
yulzari
Tech Sergeant
For the benefit of those not familiar with the common argot of those who dwell twixt Tamar and Plym: my intention was to purchase a large pasty and accompany it with strong Perry and, for my better half 'She Who Must Be Obeyed', a strong cider.
A 'Janner's Handbag' being a local allusion of a ladies handbag, being similar in size and shape to a decent pasty aka 'oggy'. A Janner being one who dwells in the city of Plymouth and addresses a lady as a 'maid' and a gentleman as 'bey'. In searching for a lost item will exclaim 'where's he to?' which displays the faintest ghost of Cornish grammar and when said item is found will then cry out 'yer tiz!'
Here too dwells the 'Green Army' of Plymouth Argyle who should appoint St. Jude as their patron Saint. Unkind perhaps but then I have never been a fan of watching 22 grown men trying to kick a pig's bladder between two sticks.
Slack-Ma-Girdle is a strong Devon cider which alludes to it being wise to loosen tight underwear somewhat for greater comfort when drinking it. Like most strong ciders, and indeed perrys, inebriation begins from the feet upwards and is often only discovered when attempting to arise at the end of the evening and finding that one's legs unaccountably fail to rise to the occasion. Slack-Ma-Girdle is named after the 18th century apple variety from which it is made. Also known as Woodbine.
Mr Google (other search engines are also available) may be your friend if you wish for more detail or elucidation.
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Elan Vital
Airman 1st Class
- 214
- Aug 24, 2024
Interesting quote from the American report of a visit of the Hispano-Suiza facilities at Bois Colombes on June 3rd, 1940, specifically the wind tunnel:
For clarity, the numbers should be 525 and 575 kph, 35° Centigrade, and 550 (350?) and 590 kilograms-force.
This is oviously referring to efforts to improve the aerodynamics of the D520 which were partially introduced on n°465 in the Vichy era. But what I find also interesting is how the facility was asked to be used for all other engine installations.
For clarity, the numbers should be 525 and 575 kph, 35° Centigrade, and 550 (350?) and 590 kilograms-force.
This is oviously referring to efforts to improve the aerodynamics of the D520 which were partially introduced on n°465 in the Vichy era. But what I find also interesting is how the facility was asked to be used for all other engine installations.
Steamed_Banana
Staff Sergeant
- 1,136
- Sep 29, 2025
That certainly changes the assessment of the D.520 in my eye. Do you know if these changes were implemented in production aircraft?
I hadn't thought of the use of the wind tunnel in improving engine intakes and fixtures, that's a very interesting detail. Seems like it was a very promising use.
I hadn't thought of the use of the wind tunnel in improving engine intakes and fixtures, that's a very interesting detail. Seems like it was a very promising use.
Shortround6
Lieutenant General
A problem for many of these France 1940 and later scenarios is figuring out was what actually possible vs. what was planned.
French planned for major increases in production and major changes in details of production models. Judging that against the French production history of the winter of 1939/40 and the many, many optimistic schedules.
There is no doubt that a number of improvements could be made to many aircraft and other weapons. The questions are how much of performance improvement could be expected and what the effects on the production lines would be.
We also have little or no idea of what the effects of what a partial invasion of France would be. Where would the front lines stabilize? How far from the front lines are the factories and how much would moving the production lines disrupt things? Plans were made for moving much of the H-S Factory in addition to setting up a 2nd factory but 2nd factories take months to set up and get into large scale production. Setting up a 2nd factory also needs to be, are you setting up shadow factory for an existing engine or for the "new" engine still under development that may need minor tooling changes?
The 109 was ahead of the D520 in a number of ways, not by much in many categories it is true but then the landscape/airscape was not static. Slightly better 109Es (better engines and better protection) were coming in the late summer and fall of 1940, not in large numbers but they were coming. Is a better D520 equal to taking on 109Fs in the spring of 1941?
There may be no BoB under this scenario but an Aug-Sept-Oct French Blitz could either take out a number of factories or force moves to remote areas of France.
French planned for major increases in production and major changes in details of production models. Judging that against the French production history of the winter of 1939/40 and the many, many optimistic schedules.
There is no doubt that a number of improvements could be made to many aircraft and other weapons. The questions are how much of performance improvement could be expected and what the effects on the production lines would be.
We also have little or no idea of what the effects of what a partial invasion of France would be. Where would the front lines stabilize? How far from the front lines are the factories and how much would moving the production lines disrupt things? Plans were made for moving much of the H-S Factory in addition to setting up a 2nd factory but 2nd factories take months to set up and get into large scale production. Setting up a 2nd factory also needs to be, are you setting up shadow factory for an existing engine or for the "new" engine still under development that may need minor tooling changes?
The 109 was ahead of the D520 in a number of ways, not by much in many categories it is true but then the landscape/airscape was not static. Slightly better 109Es (better engines and better protection) were coming in the late summer and fall of 1940, not in large numbers but they were coming. Is a better D520 equal to taking on 109Fs in the spring of 1941?
There may be no BoB under this scenario but an Aug-Sept-Oct French Blitz could either take out a number of factories or force moves to remote areas of France.
Steamed_Banana
Staff Sergeant
- 1,136
- Sep 29, 2025
If we assume the very big 'if' that France survives and stabilizes the front somehow (maybe around roughly the same lines as in WW1), it seems very likely that by spring of 1941 you would have VG 33 / 36 / 39 in some numbers, and D.551 (or whatever that has evolved into by then) in production and in operational units, with a second tier now consisting of D.520, VG 33, MS.410 and Bloch 155 (instead of mainly MS.406, Bloch 152) not to mention US aircraft like considerably more Hawk 75s, some Wildcats and Tomahawks, and British aircraft including Spitfire I, II and Vs. All of which we know are competitive with Bf 109E and at least somewhat competitive with a Bf 109F, though it seems likely to me at least that a VG 33-39 or D.551 may in fact be better.
The Luftwaffe has some ability to destroy factories but as we saw from the Battle of Britain, at significant cost. If the French and British can establish even some elements of an integrated air defense they may not have to move factories. But it is notable that the best German fighters, i.e. Bf 109E and F, have a notoriously short range, Bf 110s have a bit more range and were competitive in May-June 1940, but we know that window is closing fast. Even against Hawk 75 they are in trouble. So it seems like it should be possible to build up French factories which are already at some distance from the border, rather than set up entirely new ones.
I don't know how fully representative this map is but it looks superficially at least like France has some factories down in the West and Southwest, and some in Provence. I think the (former Breguet and LN) factories in the north-west, and the (former Bleriot and Bloch) factories in the SW are going to be safe from Luftwaffe day bombers, as is very helpfully, the (former Dewoitine) factory in Toulouse. The (former Potez, LeO, CAMS etc.) factories in Provence, which (I'm guessing?) seem in part to be for Navy aircraft, are potentially going to be exposed to attacks from the Italians, but historically they were able to fend these off. The Germans could move air units to the area of course, which may take a minute but would probably be doable ultimately, which could in turn by countered by French adjustments depending on how quickly it happened.
The large cluster of factories around Paris would certainly be in play, but at a difficult range for the Luftwaffe. Google tells me (correct me if I'm wrong) that Paris is 400-550 km from Luftwaffe airfields prior to the invasion, which is further away than London during the Battle of Britain. The Luftwaffe would be able to attack but their best bombers (Ju 87) and their best fighters (Bf 109) are going to be at the limits of their range. Thus causing them similar problems to what they faced in the BoB. The big question would be could the French establish an integrated air defense system, and as far as I know the answer to that is probably not. They did not have any radar sets deployed as far as I know, and nothing like the Chain Home system in place. Putting that together in wartime during an active invasion would be a big ask.
One other question that still stands out for me (and I hope someone here can answer) is are the French fighters going to get two speed or two stage superchargers in time. In 1940 the best French and Allied fighters can hold their own against Bf 109E and Bf 110 in a tactical an operational war. Against the Bf 109F (and later) and FW 190 this is going to become necessary.
The Luftwaffe has some ability to destroy factories but as we saw from the Battle of Britain, at significant cost. If the French and British can establish even some elements of an integrated air defense they may not have to move factories. But it is notable that the best German fighters, i.e. Bf 109E and F, have a notoriously short range, Bf 110s have a bit more range and were competitive in May-June 1940, but we know that window is closing fast. Even against Hawk 75 they are in trouble. So it seems like it should be possible to build up French factories which are already at some distance from the border, rather than set up entirely new ones.
I don't know how fully representative this map is but it looks superficially at least like France has some factories down in the West and Southwest, and some in Provence. I think the (former Breguet and LN) factories in the north-west, and the (former Bleriot and Bloch) factories in the SW are going to be safe from Luftwaffe day bombers, as is very helpfully, the (former Dewoitine) factory in Toulouse. The (former Potez, LeO, CAMS etc.) factories in Provence, which (I'm guessing?) seem in part to be for Navy aircraft, are potentially going to be exposed to attacks from the Italians, but historically they were able to fend these off. The Germans could move air units to the area of course, which may take a minute but would probably be doable ultimately, which could in turn by countered by French adjustments depending on how quickly it happened.
The large cluster of factories around Paris would certainly be in play, but at a difficult range for the Luftwaffe. Google tells me (correct me if I'm wrong) that Paris is 400-550 km from Luftwaffe airfields prior to the invasion, which is further away than London during the Battle of Britain. The Luftwaffe would be able to attack but their best bombers (Ju 87) and their best fighters (Bf 109) are going to be at the limits of their range. Thus causing them similar problems to what they faced in the BoB. The big question would be could the French establish an integrated air defense system, and as far as I know the answer to that is probably not. They did not have any radar sets deployed as far as I know, and nothing like the Chain Home system in place. Putting that together in wartime during an active invasion would be a big ask.
One other question that still stands out for me (and I hope someone here can answer) is are the French fighters going to get two speed or two stage superchargers in time. In 1940 the best French and Allied fighters can hold their own against Bf 109E and Bf 110 in a tactical an operational war. Against the Bf 109F (and later) and FW 190 this is going to become necessary.
Steamed_Banana
Staff Sergeant
- 1,136
- Sep 29, 2025
I should add, the British would certainly also contributed a large number of Hurricanes (which were already in the BoB) and though they may not be able to cope with 109F, they can somewhat against 109E and are superior to Bf 110, and very effective against German bombers.
As noted by the poster above, French should not be having just the D.520 as-is. The engine options for Spring of 1941 may include the HS 12Y-49 and -51 engines, the -51 with the better S/C, plus possibly the V-1710 and Merlin of sorts. The MB 157 should also be there, even if we discuss the actual numbers until the cows come home, same for the D.551. VG.33 or whatever is the name with the -45 or -51 engine also cuts the advantage the 109F will be bringing to the LW.
Futher - the French are not fighting alone. RAF will have far less problems in procuring the Spitfires, the best-case scenario would've been the SPitfire III in force, but even the Spitfire V will bring enough of parity.
US imported fighters will cover the needs for lower altitudes nicely.
Allies, with France surviving in the good shape in 1941, should also have the muerical superiority, and their tactics will adopt to the new conditions, even if some kicking and screaming will be there.
We also need to take a look at the LW in 1941 in this scenario. They dont get back the PoW pilots they gotten historically when France fell. They will loose yet more during the next months of air war because they weill be on the attack, over the French and perhaps Belgian countryside. There is no lul in fighting, as it was the case in early summer of 1940. Germans will also loose more aircraft. There is next to no captured French gasoline to help with fuel stocks (745 thousand tons of fuel was captured in 1940, obviuosly not all from France but still). Pilot training will take a hit even earlier than per historically.
Germany is, historically, up the creek without the paddle wrt. the raw materials. Dancey & Vajda note, already for 1939-40, that the production was hampered by the lack of alluminium, steel, copper and other; 88.5% of the plans was actually met between Sept and Dec 1939. Germany was still selling aricraft in 1939 and 1940 in order to obtain raw materials. There are no phosphates from the N. Africa, required for production of stellite.
Production of all fighters between 1st June 1940 and end of April 1941 was 2510 in Germany, and 5216 (!!) in the UK.
LW will certainly do a number on the French factories, that also means the British factories are more or less out from the hook. U-boats will be less of a menace from mid-1940 on since they must go from North Sea instead directly from the French Atlantic coast.
Shortround6
Lieutenant General
A few notes.
The VG 33 and other program was running 5-6 months late. Can they catch up or not?
It has been mentioned before. The wood in the VG 33 was not grown in France, It had to imported.
The first batch of wood imported turned out to be only about 50% useful. This is problem with wood. You don't know what you actually have until you have dried it and start cutting it in sawmills or factories. You are looking for straight grain, knot free, split free Spruce of a certain density range (weight per cubic meter or fraction of cubic meter). You have to over buy. The VG 33 may have been useful; it may not have been the strategic solution the French thought. They were not the only ones to leap on the wood band wagon and then get off again after a while.
Pretty much all new tooling and very little interchangeable parts with the D.520.
Depending on the level of boost desired (and desired power) a 1300-1500hp engine could require 200-300hp to drive the aux supercharger in addition to the power used in the main supercharger. 1500hp 12Z might be down to 1200-1300hp to prop at the 25-30,000ft altitudes with a 2 stage supercharger, Merlin 70 lost about 180hp driving the 2nd stage. But had 1655hp at 10,000ft to begin with (18lbs boost).
This is one of the big what ifs?
The VG 33 and other program was running 5-6 months late. Can they catch up or not?
It has been mentioned before. The wood in the VG 33 was not grown in France, It had to imported.
The first batch of wood imported turned out to be only about 50% useful. This is problem with wood. You don't know what you actually have until you have dried it and start cutting it in sawmills or factories. You are looking for straight grain, knot free, split free Spruce of a certain density range (weight per cubic meter or fraction of cubic meter). You have to over buy. The VG 33 may have been useful; it may not have been the strategic solution the French thought. They were not the only ones to leap on the wood band wagon and then get off again after a while.
There is little doubt that the D.551 could be put into production and issued to operational units. The question is in what numbers?
Pretty much all new tooling and very little interchangeable parts with the D.520.
The Ju 87 was very, very far from being the Luftwaffe's best bomber. Short range, small bombload, and slow. A crappy plane for a strategic bombing campaign,
Germans were starting to fit drop tanks in the late summer of 1940. Not enough but for campaign against French industry in late 1940 and early 1941?
Two speed certainly seems to be in the works. French also had the Szydlowsky-Planiol supercharger which was more efficient than conventional superchargers and used a variable inlet to get many of benefits of a two speed supercharger (or better, depends on exact supercharger/s). Two stage gets a lot more questionable. Two stage offers lots of benefits, but they add weight and more importantly bulk/volume. They need intercoolers in order to get most of their benefits. They also require a strong engine to begin with.
Depending on the level of boost desired (and desired power) a 1300-1500hp engine could require 200-300hp to drive the aux supercharger in addition to the power used in the main supercharger. 1500hp 12Z might be down to 1200-1300hp to prop at the 25-30,000ft altitudes with a 2 stage supercharger, Merlin 70 lost about 180hp driving the 2nd stage. But had 1655hp at 10,000ft to begin with (18lbs boost).
Shortround6
Lieutenant General
I think people are expecting a little too much from the US in 1940-41.
Allison built 1149 engines in 1940, 259 of them in Dec. They built just over 6400 of then in 1941, 1100 of them in Dec.
If the US is shipping hundreds of engines to France what US fighters are not getting built in 1940/41? P-39s?
Maybe the US builds fewer P40s and builds more P-36/super Hawk 75s? But then what US planes that used R-1830s or R-1820s don't get built?
Allison built 1149 engines in 1940, 259 of them in Dec. They built just over 6400 of then in 1941, 1100 of them in Dec.
If the US is shipping hundreds of engines to France what US fighters are not getting built in 1940/41? P-39s?
Maybe the US builds fewer P40s and builds more P-36/super Hawk 75s? But then what US planes that used R-1830s or R-1820s don't get built?
