Bf109K4 Doesn't stall.

I'm a frequent flyer of the DCS 109. I did a test yesterday, and also found the behavior quite odd. Ok, it doesn't spin. I managed to keep the wings level thanks to the slats. However,I also managed to keep the nose above the horizon with the throttle at idle and a sink rate of more than 20 mps. Not sure if it's normal...

It can be normal. I can do the same with the Super Dimona I am flying in RL despite she doesn`t have slats. I can throttle full back and put her into a stable stall with stick all the way back. She is stalling and sinking rapidly with stable high nose attitude, without any sign of wing drop, fully controllable.

Although they are very different birds the aerodynamics is not a subject for change:)

You can virtually do that with any.. crate. I don't understand what all the fuss is about..

me neither

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Can only talk based on my RL experience with gliders, the Astir CS Jeans and the Phoebus C, which can have that sort of stall we call "mushing stall" where your nose is almost perfectly aligned with the horizon, and you have still plenty of aileron authority.

It can be normal. I can do the same with the Super Dimona I am flying in RL despite she doesn`t have slats. I can throttle full back and put her into a stable stall with stick all the way back. She is stalling and sinking rapidly with stable high nose attitude, without any sign of wing drop, fully controllable.

 

Although they are very different birds the aerodynamics is not a subject for change:)

I can do the same with the R26 Gobe, but it's not very similar to the 109 either (unfortunately) :D

Oh well. Would be nice to hear the opinion of someone who flew it for real. Can be a realistic behavior...

Too hard to say how accurate this behavior is. P.C. flight simulator technology has, in the last eight years or so, become sufficiently advanced that it is sometimes impossible to determine whether or not something is right or wrong, without directly testing it in the real aircraft.

Let me explain. Games like old IL-2 Sturmovik: Forgotten Battles had relatively low-tech physics, and so it was often possible to see that the stall behavior was badly wrong, by comparing it to detailed videos of the real thing. It wasn't only wrong in debatable fine points, but also grossly wrong in simple matters, such as a procedural slow stall. When a USAAF training video demonstrates—step by step—a slow stall, in a particular aircraft model, under given conditions, and repeating the same steps (under the same conditions) in the simulator give a drastically different result, then the simulator is clearly incorrect.

But sim/games like DCS and Rise of Flight have sufficiently advanced physics that they can blur the line between simulated and real behavior. Generally speaking, modern simulators are accurate enough that they behave like the real thing in procedural slow stalls, and in other easily-reproducible matters. But since P.C. power is limited (and even NASA's simulations don't entirely match the real things), P.C. flight simulator games will always have some discrepancies in the details (particularly with accelerated stalls, which are just about the most complex aspect of flight).

And without having good access to the real aircraft for side-by-side comparison, it is simply impossible to tell which details are wrong, or by how much. Sure, E.D. has unprecedented access to some of these aircraft, but not all of them. And even the ones they have access to, it isn't close enough access for the fine details to be perfectly adjusted. For example, I don't think anyone who has done hands-on work at E.D. has actually performed the stall. Moreover, I'm pretty sure that no one has been able to do detailed, in-person, "back-and-forth" feedback for the 109, the way that Nick Grey did with the P-51. So, I suspect that the 109's flight model isn't quite as accurate as the P-51 is. No disrespect to E.D.; it's just how things happen.

So where does that leave us? It isn't really possible to say with certainty that the aircraft's stalling behavior is correct or incorrect. It's more likely to be slightly incorrect than 100% correct, simply because no high-complexity simulation can be perfect, at least with current technology. But I don't think it's been definitively established that the simulated 109K's unusual stalling behavior is erroneous, either—or, more importantly, how erroneous. I do know from personal experience that some aircraft can indeed stall in a similar manner. As others here have mentioned, not all aircraft must drop a wing in a stall. The Cessna 152 that I stalled (in real life) fell straight forward, with no wing drop whatsoever, while some prop aircraft can (like jet fighters) even "pancake" down, without even a nose drop, at least at certain power settings.

Some of the later fighters of WWII approached the supermaneuverable, with their astonishingly-high power-to-mass ratios. Could the 109K, with its revolutionary slats, maintain a stable stall in a falling turn, like the P-38 could? We don't know; there isn't enough information today, to the best of my knowledge. I guess that it might have been able to, at certain power settings, with extremely careful pilot input. (Too much power is likely to exceed rudder authority and force a wing-drop, while too little power would not provide enough lift to keep the nose near the horizon, causing a nose drop.) However, I wouldn't be surprised to discover that it couldn't.

109 in DCS stalls in correspondence with at least two sources anyone can refer to: NII VVS test flights report on captured 109G ("pre-stall wing rocking, then nose down with mild wing drop") and "Owner's manual" stating almost the same.

Exactly, but I can fly it all the way to the ground with the throttle at idle, the stick in my lap and the nose above the horizon. There is no "nose down'. Not saying it's not correct, but it doesn't match what you said.

Shouldn't marked dropping of a wing only occur during power on stalls or turns?

Seems legit in accordance with what Yo-Yo said.

Shouldn't marked dropping of a wing only occur during power on stalls or turns?

 

Seems legit in accordance with what Yo-Yo said.

Single wing drop happens when the lift is asymmetric on the two wings around stall speed. It can be caused by jawing or rolling movement of the aircraft.

Single wing drop happens when the lift is asymmetric on the two wings around stall speed. It can be caused by jawing or rolling movement of the aircraft.

Yeah, that was what I was trying to express. Of course, if you stomp on the rudder really hard near stall speed the wing you're yawing towards should drop, but not if you keep the plane flying in a straight line.

In two of the AS-K21 gliders I used to fly 90% of the time the left wing would drop on stall.

Regarding some interesting features of the 109 series, specially a comparison between E and G models, this interview is a great source of info.

At around 16:31 the pilot starts talking about how the 109s stalls compared to other ww2 fighters - interesting to notice how close to our experience in DCS actually is .

https://secure-hwcdn.libsyn.com/p/f/9/a/f9a4e46e96be2a2e/Episode_32_Warbirds_Over_the_Beach_BF-109G_Pilot_Rick_Volker.mp3?c_id=11781892&expiration=1479639140&hwt=59b3f03317bc360b9372993904cbf95f

I don't stall in the k4 i think it's due to the slats or maybe i am good pilot :)

It does stall, just not in the way you might all have experienced in less realistic simulators.

A stall is a loss of lift. When you have your nose high, but are still falling like a brick, you are definitely in a stall. A stall isn't the same as departure from controlled flight - as long as there is airflow over control surfaces, they will continue to exert control.

All you are seeing is a controlled stall with a stable aircraft attitude.

Is it how the real thing behaves? That I can't say. But to say the K4 doesn't stall is frankly rubbish.

he is right you know

Shouldn't marked dropping of a wing only occur during power on stalls or turns?

It depends on a number of factors. Some aircraft will have a great tendency to drop a wing during any stall, due to their aerodynamic shape. Others will be stable during a slow stall (power at idle, 1G), but drop a wing in a power stall (due to the engine torque). So, just because one aircraft is stable in a 1G stall doesn't mean it'll be stable in an accelerated stall or a power stall, nor does it mean that other aircraft will behave similarly.

It's quite complicated. Each aircraft's stalling behavior unique to that aircraft (sometimes, even to the model/block—for example, the P-40C had markedly different stalling characteristics to the P-40E). And even with a given aircraft, remember: coordination, bank angle, & power setting are not the only determinants of the stalling behavior. Drop tanks can alter the airflow under the wing, causing vortexes where none were before. A "clean" P-38 (flaps up, gear up, no external stores) had no wing drop tendency under normal conditions (that is, flying coordinated, both engines at the same power setting, both wing tanks at similar fuel masses, etc.), but lowering the gear gave it a slight tendency to drop a wing, and having external tanks gave a strong wing-drop tendency. (That's what killed Thomas McGuire—he was accustomed to the P-38's gentle stall when clean, so he wasn't expecting the nasty spin which occurred while dogfighting with droptanks on.)

yes

It does stall, just not in the way you might all have experienced in less realistic simulators.

 

A stall is a loss of lift. When you have your nose high, but are still falling like a brick, you are definitely in a stall. A stall isn't the same as departure from controlled flight - as long as there is airflow over control surfaces, they will continue to exert control.

 

All you are seeing is a controlled stall with a stable aircraft attitude.

 

Is it how the real thing behaves? That I can't say. But to say the K4 doesn't stall is frankly rubbish.

My words.. exactly.

It does stall, just not in the way you might all have experienced in less realistic simulators.

 

A stall is a loss of lift. When you have your nose high, but are still falling like a brick, you are definitely in a stall. A stall isn't the same as departure from controlled flight - as long as there is airflow over control surfaces, they will continue to exert control.

 

All you are seeing is a controlled stall with a stable aircraft attitude.

 

Is it how the real thing behaves? That I can't say. But to say the K4 doesn't stall is frankly rubbish.

:thumbup: some people dont know what a stall is.

If the stick is held to gut and ball is dead centered, and throttle is at the full idle, the behaviour described by yoyo happens. that is more than enough for me.

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