Thanks for the link.
The Flak L/60 fired a 6.5 kg shell at 860 m/s, compared with KwK 40 L48 firing the 6.8 kg AP shot at 790 m/s. Back of the envelope calculation shows that L69 will fire the 6.8 kg shot at 840 m/s, on same muzzle energy. The Flak gained high MV due it's long barrel, the weight of propellant was actually a tad less vs. the KwK 40 firing the AP shot (2.39 vs. 2.50 kg). Perhaps the Flak-derived gun should've received muzzle barrel, and another 300-500 g of propellant, so 890-900 m/s could be reached? The Panther's gun used 4 kg of propellant for the APCBC-HE projectile (7.2 kg at 935 m/s), and 3.3 kg for the APCR.
There we go - if we still allow for the costumers and engineers to proceed with a complicated and ever balooning design, it will be ready for production too late, and it would've take another year to perfect the design enough to be a really viable war machine. There is plenty of British, French and Soviet tanks with all-rear powerpack the Germans knew about, even before ww2 started, so apply the KISS principle ruthlesly. Don't go overboard with interleaved wheels, just take a page from Pz-III and increase the size & strength of suspension members for greater weight. Or copy the KV suspension/trackwork. Let DB and MAN each come out with such tank prototype(s), then choose what is better. In the meantime, demand from Krupp to came out with sloped front plate for Pz-IV
Hopefully both the Heer and designers have learned something from Tiger's weight grow, and apply that knowledge. Like that simplicity pays off. So when 30-35 ton tank is asked for, came out with a 30-35 ton tank. I don't thin that people that designed Pershing or IS tanks were that smarter than what Germany had.
As seen it the quoted paragraph - no, it was not ready for production in mid 1942.
Schmallturm was not ready for production some time in 1945, so it is a long way from being worthwhile for ww2. The up-gunned and up-armored 20-ish ton tank becomes 30-ish ton tank, and the existing Pz-III facilities will not be able to handle it.
As for the 45-50 ton tank - use the KV-1 as basis, copying it as much as possible, refine when possible, stick an ever bigger gun on it. Basically, "KV-88" for early 1943. Outclassing enemy tanks is not just what the own tank is for, exactly such thinking led to the Panther.
Do we know that L60 was ready in Spring/Summer 1942?
The Flak L/60 fired a 6.5 kg shell at 860 m/s, compared with KwK 40 L48 firing the 6.8 kg AP shot at 790 m/s. Back of the envelope calculation shows that L69 will fire the 6.8 kg shot at 840 m/s, on same muzzle energy. The Flak gained high MV due it's long barrel, the weight of propellant was actually a tad less vs. the KwK 40 firing the AP shot (2.39 vs. 2.50 kg). Perhaps the Flak-derived gun should've received muzzle barrel, and another 300-500 g of propellant, so 890-900 m/s could be reached? The Panther's gun used 4 kg of propellant for the APCBC-HE projectile (7.2 kg at 935 m/s), and 3.3 kg for the APCR.
This is going around in a circle again, you should check out the Mehrzweckpanzer thread I referenced in OP. The problem with the VK30 design is that there was none ready for production until 1943 and only then with a rushed and mechanically compromised design, aka the OTL Panther, which was just an upscaled VK2401.
The only two companies that were already working on a 30 ton chassis were Porsche and Henschel, neither of whom had tested prototypes much during 1941 and unavailable to develop a 30 ton design, because both were contracted for the VK4501 in May 1941, aka the Tiger I. Porsche's design was a mess and Henschel developed theirs into the Tiger I.
Meanwhile that left the three VK2001 designs from Daimler Benz, Krupp, and MAN. Krupp dropped out because they didn't want to rush a 30 ton design and had to scrap their 20 ton chassis work, plus was ordered to continue on with Panzer IV production. Daimler and MAN both produced the historical VK3002 designs, of course the MAN design became the Panther with all of it's problems due to being a rush job and too heavy for what the design was thanks to the L70 75mm guns, 80mm frontal armor Hitler ordered, and off the shelf turret designed for the VK3601 project and turned out to be flawed.
There we go - if we still allow for the costumers and engineers to proceed with a complicated and ever balooning design, it will be ready for production too late, and it would've take another year to perfect the design enough to be a really viable war machine. There is plenty of British, French and Soviet tanks with all-rear powerpack the Germans knew about, even before ww2 started, so apply the KISS principle ruthlesly. Don't go overboard with interleaved wheels, just take a page from Pz-III and increase the size & strength of suspension members for greater weight. Or copy the KV suspension/trackwork. Let DB and MAN each come out with such tank prototype(s), then choose what is better. In the meantime, demand from Krupp to came out with sloped front plate for Pz-IV
Even if they did the 30-35 ton medium right, it would not get into production until 1943 and service until mid-1943, by which time Panzer IV production would be locked in because this 'light' Panther would take time to develop right. It would mean no more than 60mm frontal armor sloped to the same level as the VK2401, i.e. only 10mm better, plus an off the shelf heavy turret with huge gun. It would probably still balloon in weight to at least 38 tons, just like how the Tiger I was only supposed to be 45 tons and jumped to 55 in reality. To get the Comet-like vehicle you're really looking at the VK2401, which jumped up to 28 tons in practice and with a 'magnum' 75mm gun would probably get closer to 30 tons. Historically the Panzer IV was able to up-weight 10 tons from 15t-25t in the final version.
Hopefully both the Heer and designers have learned something from Tiger's weight grow, and apply that knowledge. Like that simplicity pays off. So when 30-35 ton tank is asked for, came out with a 30-35 ton tank. I don't thin that people that designed Pershing or IS tanks were that smarter than what Germany had.
That brings us back to the entire point of this thread; the VK20 series was basically ready for production in mid-1942 unlike the VK3002 series. It just needed to adjust the chassis design to add slope and widen the tracts, but otherwise it still would use the existing Panzer IV turret, which could handle up to a 75mm L48.
As seen it the quoted paragraph - no, it was not ready for production in mid 1942.
When the time game to bump up to an L60 or 70 75mm they could use design a turret like the Schmalturm with less armor and still use the existing turret ring, just have a more powerful motor to traverse the turret, which would be somewhat taller than the Pz IV model. Being ready for production in mid-1942 has the huge benefit of being able to phase out the Pz IV from production and take over some of the Pz II production as the facilities retooled to build heavier tanks. Even the existing Pz III facilities could be shifted over, because they were already set up for 20+ ton AFV production, but would need major upgrades to switch to a 30+ ton design. Retooling them would be a lot easier, which allows for more of a shift to a single chassis to get economies of scale and simplify POL and training (which they wanted to do historically with the PZ III/IV design that never really worked). Plus the bigger design was able to have upgrades into 1944 and stay competitive unlike the Pz III and IV. Plus it buys time for a 45-50 tons design to get properly designed and tested from scratch with a high powered cannon and heavier armor that would outclass the Allied 45 ton designs and be more like the Centurion. The VK20 series chassis, any of them, would have been able to mount heavier weapons than the Pz III or IV or the Geschützwagen III/IV without overburdening the chassis. So something like the Kanonenjagdpanzer or a workable Panzerjager IV/70 could actually work.
Schmallturm was not ready for production some time in 1945, so it is a long way from being worthwhile for ww2. The up-gunned and up-armored 20-ish ton tank becomes 30-ish ton tank, and the existing Pz-III facilities will not be able to handle it.
As for the 45-50 ton tank - use the KV-1 as basis, copying it as much as possible, refine when possible, stick an ever bigger gun on it. Basically, "KV-88" for early 1943. Outclassing enemy tanks is not just what the own tank is for, exactly such thinking led to the Panther.
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It [Flak L60] was actually ready in Spring/Summer 1942, but the only turret that could take it would be the off-the-shelf VK3601/OTL Panther turret, which the shot trap gun mantel and heavy weight (too much for the early VK2401 chassis without modifications), which is why they'd need time to design the Schmalturm.
Do we know that L60 was ready in Spring/Summer 1942?