ORIGINAL: Perturabo
They were already used in 1940 in France to destroy B1 and Matilda tanks. Most of B1 tanks destroyed by gunfire were destroyed by 88s and 105s.
Correct. Mostly by 88mm Flak 36 units, others by howitzers (also used in Russia).
88s had AP ammo at least since 1939 or even from the start.
The original "Handbook for the artilleryman" from 1939 points out, that 88mm Flak 36 crews had shells with impact fuzes (direct fire mode, or ballistic artillery fire mode), time fuzes (AA-role or to lay series of air-bursts on enemy infantry in woods or over trenches/fortifications)
and AP rounds at their disposal.
So it's safe to say that the 88mm Flak pieces had AP ammunition since 1939, at least.
Also, they were already used in AT role during Spanish Civil war.
What's your source for this?
Right at the beginning of the Spanish Civil War, Germany helped Franco with initial small arms deliveries and sent 2 warships to escort and protect Nationalist troop transports from Spanish West Africa through the Straight of Gibraltar to Southern Spain. Without that help the Coup would have failed right in the beginning already, most likely. During another operation, which took several months, around 15,000 troops were transported by German JU 52s (with quite some of them being Spanish Foreign Legion troops) from Spanish Morocco to Cadiz and Malaga in Spain. The most important factor, though, before the deployment of Germany's "Legion Condor", was the vital financial aid. The Germans founded a company for handling the financial and military aid, and obtained - as compensation for that aid - mining rights for (rare) raw materials amounting to 480 Million Reichsmark. The idea behind that was to secure vital raw materials for Germany's armament industry, such as tungsten, lead, copper, iron, tin, cobalt and nickel, resources that were then delivered to Germany until 1944.
Germany sent volunteers, the Luftwaffen unit "Legion Condor", small arms and the most important factor: vital amounts of money. Some sources indicate that light tanks were delivered as well, but afaik "high tech" weapons, such as modern AA guns, newest fighter planes etc. were not handed over.
EDIT:
ORIGINAL: Perturabo
Germans have changed their policy only after it turned out that they are facing masses of T-34s and KVs in Russia. After France they were still confident enough in the successful "tank destroyer policy" (letting 88s and 105s handle the heavy armour) to attack Russia without tanks capable of fighting heavy tanks.
The Russians didn't have masses of KV and T-34 tanks. On the onset of the German invasion, the Russians had ~960 T-34 and ~500 KV tanks, according to Erickson, which includes the rather low amount of KV-2 tanks, most likely.
These roughly 1500 tanks were concentrated into 5 corps (of a total of 29 mechanized corps).
While the appearance of KV-1 (and KV-2) tanks might have been an unpleasant surprise to the Germans, the appearance of the T-34 was a shock. A relatively low profile, sloped armor and decent mobility in difficult terrain could have presented a great showstopper for the German onslaught.
In reality, the Russians lost ~20,000 tanks in 1941 and lost more than 7 tanks for every German tank killed, according to Zaloga and Fowler. Krivosheev and Erickson assess that 2,300 of these losses (in 1941) must have been T-34s and more than 900 of them heavy tanks (mostly KVs).
That means that even replacements that just had left the factories and got handed over to the units, either got destroyed or broke down quickly as well. The mechanical reliability (eg. gearbox) of early T-34 was pretty low.
According to Solonin, the 5 Corps, that were equipped with the new tanks, had lost most of their T-34 and KV tanks within weeks only.
Zaloga concluded, that at least half of the losses during summer/autumn were the result of mechanical breakdowns, (subsequent) abandonment or lack of fuel, and not the result of direct fire from tanks or German artillery.
While there were situations where say a single KV-2 (rotated in and out of a group of around 5) was able to stop the bulk of a Recon Bn, and even the Division itself for 1 or 2 days, the fact that the Germans' mobile forces were equipped with radios consistantly, giving them a higher tactical mobility, enabled them to flank or ship around Russian heavy tanks, or to try to bring forward some 88s to either track or to destroy such tanks.
Also, unlike the rare situation described above, tactical handling of the precious Russian tanks was poor, quite often.
By the way, Germans still got almost to Moscow (taking territory larger than both France and Poland together) despite not having heavy tanks and Russians having lots of them. They got into the superweapon fetishism only after they practically lost the war.
The first sentence of your assessment is correct, I corrected your "lots of them" assessment above, already. Military planners and officers in charge of supplies and armament stressed - before the attack on Russia, that the level of supplies and fuel would not be sufficient to support the campaign for more than 6 months, where some materiels would even only last 3 months only. In a way, despite the capture of fuel and weapons depots, the stubborn Russian defense near Moscow in Winter 1941, the bad weather conditions and the corresponding partial immobility of forces at the front, and the massive loss of German vehicles during the Russian counter-offensive, saved the Germans from a total collapse of the supply system.
The German High Command ignored these warnings from the supply officers, as they saw the Russian military machine to be in shabby condition and most if not all of their tanks as outdated. They thought that the lack of firepower of the bulk of the German tanks and anti-tank guns could be made up by superior use of combined arms and higher mobility. A common thought was, that the war would be over by x-mas.
Superweapons:
The Germans had massive rail guns and mortars, which I would consider to range in that class, well before things went downhill.
Even though the Germans inspected captured T-34 tanks thoroughly, the Germans had experimented with sloped armor before, but it did not make it into more serious design phases. It seems like reports from the Russian front, about successful Russian T-34s raids or operations, resulted in plans for the predecessor of the Panther, the VK 20.02 (M), though.
Mass production of the Panther was then planned to start in late 1942 already, at a point where the Germans had rolled over the Crimea and where the fight in North Africa was still raging. Probably delivery problems of parts/resources (Allied bombing efforts started to increase too), probably coupled with problems caused by the design of the new undercarriage, delayed the start of the serial production, which finally started January 1943. The output numbers did not increase sufficiently until May 1943.
While the Panther wasn't exactly a superweapon, it was a perfect tool to counter the T-34 and even heavy tanks, and it was planned/designed way before the Germans had to go onto defensive.
Also, the Germans had examined the KV-2 and the T-35 and had figured that such beasts were unpleasant opponents, but not mobile enough to avoid being flanked. They were also really big targets for the German airforce. In general, the Germans saw such (Super)Heavy tanks as obsolete and outdated.
Only the Maus, the Super Heavy Tank project, started on direct order from Hitler (which he made in 1941 already), may have picked up elements of the Russian heavy and super heavy tank concepts.
Hitler envisioned superior armor and tremendous fire power, basically turning them into mobile fortresses or "rolling bunkers", though. Initially, 150 tanks were supposed to be produced. Difficulties with the engine (187 tons toal weight, a motor fuel engine that was supposed to deliver enough electricity for 2 E-engines acting as main drive) and Allied bombings delayed production and assembly of the 2 prototypes, so that the first Maus couldn't be assembled for testing before December 1943.
In turn, the Tiger II tank was supposed to be superior to every Allied tank out there. Due to the attempt to streamline the design of (shared) parts for the upcoming Panther II tank, the production of the first prototype was delayed until December 1943 (although ordered and planned to be finished in January 1943). The changing situation at the Russia front also influenced design and delayed the serial production even more, as better protection for the crews and better armament was favored over speed now. Specs for this tank were issued by the Heereswaffenamt in August 1942 already, though.
So if you consider this project to be "fetishism" too, then it was initiated well before Germany went onto the defensive.
I would agree with you if you would consider projects like the V2 or the Horton flying wing to be such fetishism, as the Germans hoped that these and other projects could lead to tools able to reach say New York for example, and eventually turn the tide in their favor. All these projects were based on long-term research and development either started before or early in the war, though, with the Nazi government really digging most of these concepts when things went downhill already, though.