YaGramps: Centrifugal force is a thing when performing a tight turn, you know.
And once you discover the rudder you'll find flying to be much, much easier.
NormanKnight.GER: Well, centrifugal force has nothing to do with it, imho.
If you fly straight all lift forces produced by your wings is directed upward. If you keep the same speed and trim the plane, your nose stays on the same angle of attack and your altitude does not change.
Now: If you roll, lets say gentle 20 degrees, to one side, the lift produced by your wings isn't directed upward only, but sideways, too. The fraction of force directed sideways is missing form the upward force now. The plane starts descending. Since the center of mass is in front of the center of lift, the planes nose drops. Furthermore the plane starts turning, from the part of your lift that goes sideways.
There is no rudder involved in this.
Not that I didn't have discovered the rudder yet ...
... but the rudder alone isn't really meant to fly a turn. It's more for "fine tuning", for coordinated turns. It is also important to counter engine torque as well as counter crosswinds on landing.
But don't get me wrong:
I don't want to make Red Baron a bad game. Most flight sims of the 80s and early 90s shared exactly the same flaws in flight modelling. Some don't even have the rudder simulated. Everything is heavily simplified.
I primary wanted to express my joy about how well Knights of the Sky respects the details I wrote about on top. It feels much more natural. The plane acts more like you'd expect, when coming back from more modern flight sims.
If you are rolling on to your back to take aim at a lower enemy, then you haven't worked out the rudder- it's as simple as that. You can get through the entire war and never have to roll over like that to draw a bead on an enemy -if you use the rudder properly.
And I'm not talking about gentle 20 degree banks either, I'm talking middle of a dogfight, life or death 90 degree joystick into your stomach turns, where you can be side on to the horizon and still be forced down into your seat by the centrifugal force. Of course you lose height doing this- you can see it right there on the altimeter. But the nose isn't going to drop like a stone just because you're not perfectly level. If ALL the wing's lift was needed just to stay straight and level, then there'd be no lift left over to be able to climb. At all.
It's also worth noting that if you fly early war fighters like the Bullet and Eindekker, you get exactly what you're describing with the falling nose, because they're so underpowered that they really do struggle to stay straight and level, and banking takes away from that tiny pool of lift available. But later fighters have more power and better trim to avoid that.
The most efficient way to turn while maintaining height is a 45 degree bank, crosshair on the horizon, and a combination of upward stick and rudder toward your turn. It is NOT just for fine aiming: you should be using your rudder in every manoeuvre you make. Hell, in real life some pilots are skilled enough to fly on their sides almost totally maintaining altitude using *just* the rudder. And when they do, the nose sure as anything isn't pointing downwards.
If you find joy in the physics of Knights of the Sky, that's great. If you prefer it to Red Baron's physics, that's perfectly fine too. Red Baron's physics aren't 100% realistic, as anyone will tell you. But the flight model doesn't 'suck' in the way you think it does.