Flying some offline missions I have created, I had a Ju 88 follow me down in a dive at 452 mph!!! I have film of this stuff. So, I took the JU-88 offline and spawned from a 30k field. I rolled into a dive and reached 581 mph TAS (about 470 mph IAS) at 12-13k before anything failed (vertical stab). I pulled back power to idle at 550 mph TAS, allowing gravity to accelerate the bomber until structural failure.
I have no doubt that the VNE or even terminal velocity for the Ju 88 should be a heck of a lot lower than what it can do in the game.
Plus, when the wings failed at 583 mph (at around 8k), there remained some unusual graphic remnants.
My regards,
Widewing
