The problem is that tanks are heavy. That's one reason you don't see them flying very often. In order to get the tank light enough that the wings could keep it aloft long enough to make it to the battlefield, they had to completely strip it down. It had no armaments or ammunition, it didn't have any headlights (because those are supposedly quite heavy) and it carried a minimal amount of fuel. Basically, it couldn't function as a tank by any definition of the word.
But as far as being a tank-shaped vehicle that could fly, it actually kind of worked. For a test flight, they had another plane tow it into the air, at which point the A-40 glided down to earth and was driven back to base by its test pilot/driver. At which point he apparently said, "OK, let's never fucking do that again," and the program was scrapped.
"Oh God, how much did we drink last night? What did we build?"
The ME 163 Komet Was Perfect for Making Pilots Shit Their Pants
The Nazi-engineered Komet was the first rocket-powered aircraft to ever see use, the first swept-wing fighter plane ever made and the fastest aircraft the world would see for years. Those are the only positive things that can be said about it.
So much of its design time went into attaching needlessly big rockets that the Komet design team forgot literally everything else about flying. For starters, it had no landing gear. Instead, the Komet was shoved on top of a disposable set of wheels during takeoff, which usually ended with the wheels flying up and damaging the aircraft. To land, it used a single spring-loaded skid that would hopefully deploy in time, because rocket-powered planes need the exact same stability as a one-legged skier to land without catastrophe.
The results would have been tragic, had the pilots not been Nazis.
Also, they neglected to equip cockpit pressurization, forcing pilots to constantly fight for consciousness as they screamed through aerial battles at irresponsible speeds. But that wasn't even the Komet's biggest problem. Nor was it the fact that the insane, barely tested rocket fuel mixture used was completely unstable and prone to exploding at any time like Timothy Dalton at the end of The Rocketeer.
"No pressure, Franz, but I've got 50 marks on you dying in fire today."
No, its biggest problem was that, even if the stars aligned and the Komet didn't immediately wreck itself on takeoff or spontaneously combust seconds after, it was too insanely overpowered to attack any enemies. Its ludicrous rockets made it fly so fast that it had only seconds to aim before blasting miles past enemy fighters.
And the designers filled the Komet with only seven and a half minutes of that crazy unstable rocket fuel, so pilots were expected to take off, find the enemy, stage their attack, get back to base and land safely in under seven and a half minutes (although that last part may have been optional).
The Germans recruited heavily from suicide hotlines.
When not writing, Patrick can be found fawning over the greatest recording company of all time, Ill Music Records.
For more concepts that didn't quite work, check out The 5 Most Ineffective Anti-Drug PSAs of All Time and 7 Hilariously Failed Attempts at Politically Correct Toys.