Why was P-36 so successful in the battle of France?

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Good point about the weather, but the Germans had that same problem at the beginning of Barbarossa right? They wanted to start it much earlier but trouble in Yugoslavia delayed it.

The only way I can see of the war being delayed a bit in France is something else delaying the Germans, such as perhaps arming the Poles though of course that would have angered the Soviets as well. I think it was a mistake to throw the Poles and Czechs under the bus.

For that matter, a fair number of 'German' tanks invading France in 1940 were actually Czech made. The Czechs had better tank designs than most nations in the world.
 
For the bullets you need a lot more than 60 days. The French went their own way as far small arms ammo went. The British accepted the use of multiple calibers and supply chain issues.
But once Dunkirk was over the British supply problems were in some ways easier, at least for a few months, just dump the stuff in England and just sort it out there. Send the already existing British stuff to Egypt or where ever.
The US may have been able to supply some 75mm and 155mm artillery ammo, to the French, how much dates from WW I

The Swiss also had the firm of Adolph Saurer AG. Which made various types of textile machinery, Trucks/buses, licensed aircraft engines in WW I, worked on their own petrol and diesel engines between the wars. This was the outfit that was licensed to make the later H-S engines. Another Swiss manufacturer of H-S aircraft engines was the Swiss Locomotive & Machine Works. The Swiss did have a pretty fair industrial base, Like Oerlikon. The Swiss had been exporting machine tools to Britain to help build up their aircraft industry during the late 30s.
The US wound up copying several different designs of Swiss machine tools at the out break of WW II because the Swiss could not meet the demand. The three companies were Tornos, Bechler, and Petermann. These were called automatic lathes in Europe but in the US they were known as screw machines.


To get 1200-1300hp out of the 12Y you have two choices.

Higher RPM, doesn't look good if they already have to start beefing things up to get the 2500rpm mark (and the only major user was the Swiss). Increasing the rpm increases the friction and the stress on the moving parts by the square of the rpm.

Higher boost pressure. Which also goes back to the strength of the parts. You aren't squaring it but you are going to have to raise the BMEP by around 20-30% to reach your goal.

Hispano engines were not noted for making it to 100 hours on test as it was.

The Russian M-100 went about 470kg, then there was a somewhat steady progression of weight increases through the 495-510 kg of the M-103 to the 570kg of the M-105 to the 600kg of the M-105PF. Granted it gained a two speed supercharger along the way (and 3 valves per cylinder) but it didn't hit 1300hp either (until 1944?) and the 1260hp rating was at 700 meters (yes 700) and was achieved by shortening the engine life. Also note that the M-105PF ran at 2700rpm.

The 12Y-50 was supposed to weigh 492kg.
Please note that the S-P supercharger was supposed to lower the inlet temperature by 60 degrees C which is where a lot of the improvement in the forty series engines that used it came from. The original H-S supercharger wasn't very good. Now perhaps the S-P supercharger was over complicated, but it had already made a major contribution to the power output and expecting a another major jump in efficiency (as opposed to brute force pressure) doesn't seem likely.

There are teething problems and there are problems that are not teething but fundamental limitations.
The 150 X 170 H-S V-12 engine dates from 1928.

The 12Z had teething problems but it used a new crankshaft, new crankcase, new connecting rods (fork and blade) new cylinder heads and new valve gear.

The 12Y was flogging a dead horse.
 
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Wild_Bill_Kelso said:
The Czechs had better tank designs than most nations in the world.
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And the Germans made few small changes. Minor actual change was that they had the gunner in the front of the hull stand up and join the the turret crew. Very cramped indeed.
But now you had a gunner and you had a loader and you had the commander who was actually trying to command the tank. The advantages of a 3 man turret crew sometimes don't show up in a list of statistics but the success rate of tanks is more in line with their rate of engagement which is not the rate of fire.
Rate of fire is how fast the commander can identify the next target (and perhaps the one after that) and direct the gunner to the new target after the present target has brewed up or disappeared and get the first round fired at the new target. It is sort of a force multiplier. The commander is also keeping track of the tactical situation and hopefully realizes when things go pear shaped and gets the tank and crew somewhere safer before rounds start bouncing off the back of the tank. If the tank commander has his eye glued to the gun sight it is all too easy for the enemy to sneak up behind you.
Giving the 3 man crew room to actually work in did make things a lot better.
 

I agree, 3 man turrets were the way to go, and the Czech tanks were originally two-man, as not everyone had figured that out, but at least the Czech tanks had the capacity - including a fairly large turret which ultimately, three men could squeeze into.

For situational / command awareness the tank commanders really had to stick their heads out of the hatch, as dangerous as that was, and that is why the welded shut hatch of the SOMUA 35 was such a bizarre feature and a design fail.

The Czech tanks had good armor, guns, machine guns*, good engine, wheels, transmission and suspension. Slightly narrow tracks but that was typical of the early war. They had radios. Most important perhaps, they had some room for improvement and further development, which turned out to be one of the most important features for armored vehicles of the time. Overall the vz 38 was clearly better than a Pz II and compared fairly well to an early Pz III. It was superior in terms of sophistication and overall design to all the French or British or Soviet light tanks, IMO. Arguably a bit better than a US M3 Stuart.

As for the Swiss industry - yes, the Swiss were, and are today quite sophisticated. On the level of design and small scale production, they were and are world class. But not, in 1940, heavy industry. It's just a very small country, there is a reason why they import almost all of their cars and heavy military kit. They didn't have the kind of industrial capacity that the French had in Toulouse, Lyon and the seven big nationalized aircraft factories around France (plus the engine factory). The French built and put into operation 200 LeO 45 bombers in 45 days during the war. The Swiss couldn't build that many watches or wheels of gruyere that fast.

There is no getting around 40 million vs. 4 million. It's comparing melons to peas.

And both the HS 12 Y (or Z) series, as well as the Gnome Rhone, were very successful designs. Despite not really being improved much after 1940, these were the basis of a large percentage of Allied aircraft.

* as we know, both the Besa and the Bren were based on Czech designs. As was the Uzi.
 

The German invasion of Russia would have been slowed with or without the invasion of Yugoslavia, precisely because the mud season in 1941 ran long. Even forgoing that invasion in the southeast, the weather and ground conditions through Poland meant that a May 41 invasion of Russia would have been ugly, I think.

Whether the problem was a Fuhrer-tirade demanding an attack on Yugoslavia, or weather on the Eastern Front, launching Barbarossa at the end of May didn't seem to be in the cards.
 
Wild_Bill_Kelso said:
There is no getting around 40 million vs. 4 million. It's comparing melons to peas.
Click to expand...
And yet we have people who think that Australia could build several types of aircraft and/or engines in 1940 with a population not much different. With less industry and scattered hundreds if not thousands of miles apart.
The Swiss only needed to build 1 to 2 dozen fighter per month. The joke about watches falls very flat. The Swiss in 1930s were mass producers of watches and clocks. The Swiss had two different categories of machine tools. One was general purposes machines that could be used by the customer to build wide assortment of of parts (suitably sized) these were available to anyone who wanted to but them and were sold to many different countries. The other class of machinery was was specialized watch making machinery. It was restricted and not for export. It took the Japanese many years after WW II to break into the watch market and it took them until the late 50s/early 60s to obtain or copy the Swiss machinery.

While the Swiss could not compete in terms of size with France they had a number of large companies. Like Brown Boveri in 1911

In 1914 they built the largest steam turbine in Europe, 40,000hp. They supplied some ship turbines but mainly electrical powerplants.
other Swiss companies built things like this.

Some of them were made by the company that made some of the H-S 12Y-51 engines but I guess that after handling 140 ton locomotives a 1/2 ton airplane engine was too hard for them to handle?
Swiss did make some of these

A 34mm AA gun with water cooled barrel. 250rpm.
They must have loved a cheese quite a lot to invest in such weapons to defend it



Wild_Bill_Kelso said:
And both the HS 12 Y (or Z) series, as well as the Gnome Rhone, were very successful designs. Despite not really being improved much after 1940, these were the basis of a large percentage of Allied aircraft.
Click to expand...
The HS Z was not really a successful design. The French version went nowhere and the Spanish version went into some of the Post war 109 clones until the Spanish decided they were better off buying Merlins.
The Gnome Rhone was another engine in the midst of change over. The K engine had come to it's end (edit, they had moved from the K to the N in the late 30s but it too had reached the end) and they were trying the R in a few experimental aircraft. Post war the engine was transferred to SNECMA but it went nowhere, One twin engine plane was fitted with a pair. SNECMA went on to build Bristol Hercules engines under license.

Edit: Brown Bovari built a successful Gas turbine industrial generator in 1939. They were supposed to deliver a gas turbine locomotive to the Great Western Railway just before WW II started but they did deliver a modified version in 1949.
One might also look at the Sulzer company including their Diesel engines.
 
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Sulzer was a pioneer in the development of the diesel locomotive

sulzer engine, 6LDA28, LVA24

derbysulzers.com
And a major player in the marine and large stationary engine market, now as a part of Wartsila.

Engineering:History of Sulzer diesel engines

This article covers the History of Sulzer diesel engines from 1898 to 1997. Sulzer Brothers foundry was established in Winterthur, Switzerland, in 1834 by Johann Jakob Sulzer-Neuffert and his two sons, Johann Jakob and Salomon. Products included cast iron, firefighting pumps and textile...
handwiki.org
Years ago I toured a textile plant in Turkey . All of the equipment was made in Switzerland by Sulzer

Sulzer P7100 and P7200, 360 cm

Ihr Spezialist für hochwertige, überholte Textilmaschinen, insbesondere für Webmaschinen.
www.textilmaschinen.de
Escher Wyss was another Swiss manufacturer of large machinery such as steam turbines.

Escher Wyss & Cie. - Wikipedia

en.wikipedia.org
Oerlikon was another large company make heavy equipment such as generators and elecrtic locomotives
Sauer was a pioneer of diesel truck in the 30s
Switzerland was a heavily industrialized country pre WWII
 
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Wild_Bill_Kelso said:
The radios were basically due to a shortage. The S-35's performed quite well in combat, but I think the biggest (and strangest) problem was that the hatch was welded shut.
Click to expand...
The biggest problem was the 1-man turret. A terrible idea. Situational awareness was a real problem for French tank commanders due the heavy work load performing as commander, gunner and loader in extremely cramped conditions coupled with the terribly limited field of view common to all French tanks.
The ridiculous domed cupola mentioned in the video is shown in this video at the 10.25 mark
Thats what I call using your head
Lindy Beige may be an acquired taste but he gives a very animated discussion of the problems of a one man turret.
 
Shortround6 said:
And yet we have people who think that Australia could build several types of aircraft and/or engines in 1940 with a population not much different. With less industry and scattered hundreds if not thousands of miles apart.
Click to expand...


Well, that's definitely a fair point, but Australia actually had almost double the population that Switzerland did and while very remote, despite the best efforts of the Japanese, was not cut off from an increasingly robust maritime supply line from the UK and (especially) the US. Switzerland by contrast basically had to get all necessary materials, notably strategically important metals and parts which were tightly controlled, through fairly hostile Axis lines or they had to fabricate them on their own. And that puts an extra strain.

I'd just guess with a relatively similar level of education, and double the population and strong materiel links to US and UK supply lines, Australia was actually in a better position. But it's arguable I won't attempt to deny that.

I've been to Switzerland, I know their history very well and I have several friends there (and some who have left and live as ex-pats). My joke about the watches is from an admiring point of view. And to be fair to your point, the Swiss did in fact manage to not only build aircraft under license (MS 406 with their own local improvements, including the uprated 12Y we've been discussing), they also produced some of their own aircraft designs, at least one of which was relatively modern.



However I do think Australia was better positioned to ramp up their armaments industry, albeit nowhere near at the scale of France. And theoretical Ozhawk notwithstanding, their Boomerang was probably more useful overall than the EKW C-36 (or say, a Morraine 406)

Well, I'd say the 12-Z was just another version of the 12-Y, as you your self noted, which was strangled in the crib as it were by the German invasion. With another two or three months, they might have gotten in sorted, or maybe not. We'll never know. But I'd put my money on Hispano sorting it out.

But as the basis of the Soviet Klimov it certainly contributed a great deal to ultimate Allied victory.

If the development of the Merlin or the Allison had suddenly ended in May 1940 I don't think they would be so famous.

The Gnome Rhone 14 series was similarly an effective design which never reached it's full potential. But it was good enough that the Germans used it for example on their successful FW 189
 
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But on a very small scale compared to France
 
Wild_Bill_Kelso said:
The radios were basically due to a shortage. The S-35's performed quite well in combat, but I think the biggest (and strangest) problem was that the hatch was welded shut.
Click to expand...

The APX 1 CE turret of the Somua S35 did not have a hatch, but an observation cupola with 4 observation apparatus.
CE meant '' chemin élargi " (enlarged way) meaning that a crew member could if needed access to the turret to assist the tank commander. This turret was considered as a '' 1.5 '' men turret.
The commander entered the turret via a hatch in the back of the turret.
 
Frog said:
The APX 1 CE turret of the Somua S35 did not have a hatch, but an observation cupola with 4 observation apparatus.
Click to expand...
yeah that's what I meant. It should have been a hatch

I have read detailed account of the S-35 in combat, it caused the Germans some serious problems. My grandfather was in the French army and witnessed on in action, he took a photo of it after it was finally abandoned. I have it on my fridge.
 
Three vision choices, not four. More importantly, the cupola was fully rotating on amazingly smooth bearings. I've seen video of an R35 turret recovered in the 1980s that had been sitting outside, upside down, rusting since 1940. They flipped the turret over and just spun the cupola around as easy as a lazy susan with a pie on it.

The vision devices on the APX-1 cupola were an episcope (vaguely similar to an armored periscope, except vision was directly in line with your eyes), flip down binoculars, and what I think was a simple armored slit with a very heavy cover as an emergency backup.
 
as I have noted the12 Z used a a different crankshaft, different connecting rods, different crankcase, different cylinder heads, and used a different fuel system (fuel injection) but if want to believe that it was just a different version that could be sorted out in a few months, I guess those facts won't stop you. The fact that the US engine makers seemed to take a year to two years to go from 1st test run of a major revision to an engine to the 5th production engine delivered just means the US makers were way, way behind the French I guess. Like Wright running the first 1300hp R-1820 in Jan 1942 and delivering the 5th engine in April 1943.

What the Soviet Klimov contributed in combat has very little to do with the evolution of the Hispano 12Y engine and the Klimov variants in regards to power output, power to weight ratio or longevity/durability. We can look at the Klimov's and ask why did the Russians do so and so or such and such to get more power or to solve durability problems as an insight to the Hispano engines.

Confusing the end of development due to the war situation with good or bad design or design features doesn't get us anywhere. The Merlin did take a while to develop but by 1940 the basic engine design was sorted out. If Britain had fallen in 1940 the Merlin, as an engine, would still have been a good design. The Allison in the summer of 1940, not so much.

But we also have different standards.
The Allison failed in 1940 because it wouldn't pass the US 150 hour test. After the Allison got a new crankshaft and a new crankcase in late 1940 (and the engine test stand was changed) the Allison became a very fine engine and passed the 150 hour test.
The Merlin wouldn't either in 1940, but it passed the British 100 hour test.
We don't know how well the H-S would pass either test. We do know it failed miserably at 850hp in 1933 in a test for the Russians. There were changes to try and solve the problems but the Russians decided to accept the unmodified engine after down rating it to 750hp and that was the start of the M-100 series of engines with their constant strengthening and weight gain while trying to improve performance. We have no idea of how well the Hispano 12Y-51 or the 12Z would have done on such tests. We have some indications because the Swiss found they needed to add about 28KG to the weight of the pre-war 12Y-51, They also didn't change much in power going from 87 octane to 93 octane.

As for "The Gnome Rhone 14 series was similarly an effective design which never reached it's full potential. But it was good enough that the Germans used it for example on their successful FW 189"

Uh, one, count it, one FW 189 used an Gnome-Rhone 14 engine.
However it was a Gnome-Rhone 14M engine which had nothing in common with the 14N or the 14R except the name and the fact that both were 14 cylinder engines.
The 14M was the small diameter 19 liter engine of 700hp. The 14K, 14N and 14R were all much larger in diameter and of 38.7 liters displacement.

One reason the 14K and 14N didn't reach their full potential was that, like the AS Tiger, they didn't have a center bearing on the crankshaft.
In order to reach their full potential on the 14R they added just about 200kg to the weight of the engine (new crankcase, new crankshaft, new rotating parts new cylinder fins, new cylinder heads etc)
Apparently after years of work (it was still catalogued in 1953 but unsold?) the French gave up on it and took out a license for the Bristol Hercules 700 Series engines.
Rerating the 14R on 100/130 fuel brought no increase in power although the engine gained 130kg between the 1946 version and the 1953 version. The 1953 version was as making the 1600hp take-off power at 3700ft.
In 1953 the The 14R could do using 100/130 fuel what the Wright R-2600 could do in 1940 using 91 octane fuel and weighing over 100lbs less. The 14R was a bit smaller in diameter though.
 
Article on the S-35 in German service.

SOMUA S 35 in Second Hand

Captured French tank SOMUA S 35, or Pz.Kpfw.35 S (f), in the German, Hungarian, Italian and … French armies
warspot.net
 
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