Wierd stall characteristics in planes

[ryguy 10]

The planes in arma 2 have strange stall properties... For example, when the plane stalls instead of the nose immediately dropping, the nose kind of just hangs there until the plane gets this ridiculously slow airspeed. Then the airplane starts to fall, nose still high. In an improvement you guys should make it so the nose drops and the airplane "dives".

Another odd thing is that the plane slows instead of gains speed in a turn. Kind of odd, what should happen is the stall speed should increase but the speed stay the same/increase.

Just some suggestions. :bounce3:

[frederf 0]

I'm not criticizing your criticism but... ArmA2 just plain ain't a flight sim. It would be nice I guess but really ArmA is an infantry sim and that means having a slew of battlefield aspects that support the infantry simulation. The farther from boots and dirt you get in ArmA the less fidelity you encounter, universally.

The flight model in ArmA is really on par with about... EA's Battlefield 1942. Functional but just enough to get from A to B.

As one having some aviation background, I'd like to say that stalling is a delamination of airflow from the wings that can happen at any speed. Many civil aircraft have nose-down departure tendencies built into the airframe but that doesn't necessarily have to be the case. I imagine the A-10 behaves traditionally but I wouldn't bet $100 on the F-117A or F-35 or anything on the sportier/exotic end of the scale.

Standing a jet fighter on its tail until very slow speed is more similar between ArmA and real life than you give it credit for. ArmA is no shining flight model to be sure though.

Also "stall speed" should never change for a given configuration, since it's merely a benchmark at which level flight at that speed that requires a certain AoA where the airfoil airflow is just on the verge of delmaination. It might require a lesser AoA (thus higher speed) for reattachment but stall speed only cares about the lamination-delamination threshold.

Usually airplanes lose speed in turns, especially more than 2 Gs lateral.

[max power 21]

Turns should decrease airspeed unless the drag caused by the increase in angle of attack is overcome by gravity as in a diving turn.

Stall speeds due to low speed should increase as height or temperature increases, but a stall can happen at any speed if the angle of attack is such that airflow over the wings is no longer creating meaningful lift.

[hellfire257 3]

Yeah, the stall models are really poor. The planes always feel weightless in flight, but in a stall it feels as though the planes don't have any thrust behind them! You cannot put your nose down either to increase speed. Basically, if you stall in ARMA, you're screwed.

[TechnoTerrorist303 10]

The flight model is a bit strange and could certainly do with some attention... I think I'd even pay for a DLC that fixed it so that flying was a bit more realistic.

The biggest problem I've experienced is the one mentioned above where you can go into a turn and literally fall out of the sky. It's like as soon as the aircraft is on its side the game decides that air no longer flows over the wings and calculates your airspeed and lift using atmospheric properties similar to those of treacle. Have you ever tried flying an aircraft through treacle? I'm pretty sure BIS haven't but I suspect they've managed to simulate it pretty accurately.

[CarlGustaffa 4]

The biggest problem I've experienced is the one mentioned above where you can go into a turn and literally fall out of the sky. It's like as soon as the aircraft is on its side the game decides that air no longer flows over the wings

Uhm, that's precisely what happens in the real world, at least for GA planes; you have no lift component when aircraft is flying 90° bank - it's quite natural. In a jet with enough thrust you would have to point the nose upward in such a turn.

Get to know the flight envelope, real or not. Pilots do it all the time. Stall characteristics might be better, I don't know, I've never stalled a jet - in fact I've never flown one as I guess most here haven't as well :p I have no idea how a jet fighter would stall, but the current behavior is not correct for a typical GA aircraft (which I have stalled).

[ryguy 10]

Also "stall speed" should never change for a given configuration, since it's merely a benchmark at which level flight at that speed that requires a certain AoA where the airfoil airflow is just on the verge of delmaination. It might require a lesser AoA (thus higher speed) for reattachment but stall speed only cares about the lamination-delamination threshold.

Uhm... Stall speed shouldn't change for configuration?

Flaps decrease the stall speed. Turns increase the stall speed. Two examples right there, two different configurations...

I think what you meant to say is that critical AoA shouldn't change based on different configurations.

[frederf 0]

Read more better.

[ryguy 10]

:confused:

[CarlGustaffa 4]

Hehe, "for a given configuration" != "changing configuration" :)

[ryguy 10]

Ah, but I don't count a banked airplane as a "configuration" right?

[frederf 0]

Stall speed assumes level flight. So banking, while not a configuration change, doesn't change stall speed. The whole concept of a stall speed is actually very old fashioned thought. I could have a 747 going 20 knots, but not be stalled.

[CarlGustaffa 4]

Huh? Well, yes it does. It doesn't change the parameter "stall speed" since yes, it's based on level flight, but it does change the speed at which you stall. Although it's not a "configuration change" as such, stall speed (again, not the "parameter value" but the "actual value") will increase with bank angle. At 0° you'll stall at say 60 kts, while at 45° you may stall at 85 kts. But it's not a configuration change like changing flaps, gear, or weight moment.

[ryguy 10]

Stall speed assumes level flight. So banking, while not a configuration change, doesn't change stall speed. The whole concept of a stall speed is actually very old fashioned thought. I could have a 747 going 20 knots, but not be stalled.

I think you're confusing groundspeed with airspeed.

[CarlGustaffa 4]

Indicated, calibrated or true airspeed? :) But, ok, so that's what he meant with the 747 example, I couldn't make sense of that one...

[TechnoTerrorist303 10]

Uhm, that's precisely what happens in the real world, at least for GA planes; you have no lift component when aircraft is flying 90° bank - it's quite natural. In a jet with enough thrust you would have to point the nose upward in such a turn.

I am aware of this :) I should have been slightly more correct with my posting.

You lose lift in a banked turn but in this game it seems that not only do you lose what you had but you also suddenly start to generate "anti-lift" and airspeed falls off far too fast as if the engine is losing thrust.

I haven't flown a real jet, my rl flight experience is pretty limited at the moment (working on that one). I have however played flight simulators since "Aviator" on the BBC Model B and I can tell you that this just doesn't feel right. I know Arma 2 isn't a true flight simulator but this needs fixing.

[frederf 0]

I think you're confusing groundspeed with airspeed.

Indicated, calibrated or true airspeed? :) But, ok, so that's what he meant with the 747 example, I couldn't make sense of that one...

Nope, airspeed. If you were flying 90° pitch up or 90° pitch down, and your airspeed was 20 knots... you would not be stalled because the airflow was still laminated to the wings (AoA would be close to zero.)

I am aware of this :) I should have been slightly more correct with my posting.

You lose lift in a banked turn but in this game it seems that not only do you lose what you had but you also suddenly start to generate "anti-lift" and airspeed falls off far too fast as if the engine is losing thrust.

I haven't flown a real jet, my rl flight experience is pretty limited at the moment (working on that one). I have however played flight simulators since "Aviator" on the BBC Model B and I can tell you that this just doesn't feel right. I know Arma 2 isn't a true flight simulator but this needs fixing.

The reason ArmA does the massive speed drop off for pulling G's is that the flight model is limited in its fidelity. The flight model doesn't handle things like accelerated stalls, FCS limits, corner speed, etc. In ArmA the more speed you have, the more powerful of a turn you have access to. In real life this isn't the case. The speed drop off is for gameplay balance so you couldn't pull a super turn just because you had a lot of airspeed "in the bank" so to speak. If you have access to EA's battlefield 1942, you'll notice the same behavior; turn ability increases with speed without limit giving some truly alien capabilities.