I'll have a go at your points, but out of order, Tommy.
First, the stall horn. you're *supposed* to hear it. Think of it as the aerial version of screeching tyres: it tells you you're near the edge, the more it screams, the closer; and, just like screaming tyres in the distance, if it suddenly goes quiet, you know he's lost it.
Fair enough, but what does that mean? What it really means is that the air around your wings is being so pulled out of shape that it's not "sticking" to the wings and holding them up....you're losing lift. Think of it this way: lets say for the sake of argument, that your plane wieghs two tons in normal gravity. Let's also say that your wings are so designed that they will support two tons at 200 miles an hour. Then you pull a tight turn, at 2 G. That means there's twice the force of gravity (subjectively) acting on your plane, making it weigh 2 x 2 = 4 tons. You know that it needs to do 200 MPH to support 2 tons, so now you can see you'll need more than 200 MPH to support 4 tons effective wieght. It would be easy to say you'll need to do 400 MPH, but the maths isn't that straight forward. However, you should get the idea. This principle works which ever way you're facing, upside down, straight up, straight down etc. If you pull hard on the stick, you create G force, and if you do that, you need speed to hold the plane up. It's the speed of air over the wings that makes the difference between a 2 ton plane and a 2 ton lump of metal going down fast.
A good combat turn is somewhere between hearing the stall horn and black out. Once the fight begins, especialy in a turning plane such as a Spit, Niki or Zero, you should be hearing the stall horn almost all the time; or you're not trying hard enough. Later you'll learn to be smoother and not squeal the tyres so much, but for now you should be making them scream. It IS more sensitive than other sims. It's realer. Most pilot deaths in WWII were simple crashes. These planes were the F16's of their day, and they bite the newbie.
Secondly the flip over.
As I said before, wings need speed to be able to generate lift. There's quite a collection of different forces in action on the wings during a turn, but let's go through the main ones: Speed, movement radius, torque and control surface deflection.
Speed: As said above, you need speed to make lift. If that speed falls away, the wings stop lifting, and you begin to sink. So far, so good. But what happens if only *one* wing is going too slow?
Now you ask how can one wing have a different speed than the other? Well, one's on the outside of a turn, the other's on the inside. The outside one goes faster.
But the needed speed and the load on the wing are related. How can they be different? Well, as the plane tries to turn the propeller, the propller tries to turn the plane. This is called a torque reaction, and it means *in effect* that one wing is being twisted up, and the other down. The wing being twisted down feels (to it's self, if you follow the logic) heavier, and thus needs more speed to support it.
Lastly, the aerlirons themselves create drag as they work, to work they need to push down on one wing and lift up the other. Again we can see different forces on each wing.
What does this mean? It means it's possible to stall one wing before the other. And when that happens, the stalled wing drops, and the unstalled wing keeps lifting, spinning you around the longitudinal axis. This is called a "snap roll", and it can kill you. However, some planes (the Corsair is a good example) do this so predictabley you can actualy *use* it with practise to spin your plane around it's axis and thus change direction quicker than anybody will ever follow. But you'll need a *lot* of practise to get that one right.
So, to make it short:
Stall horn = scraming tyres. Pull less, or go faster (it's the same)
Snap rolls = Pull less, go faster, (it's the same)
