P51 and its stall . what !!!!

[KoN_]

Ok for a casual gamer this flip over and go into a uncontrolled spin seems crazy over the TOP .

Ive seen so many P51s just flip over on to its back when in a turn fight . Seems this is the only , ONLY craft to actually behave like this in the game .

If this was the case in real life i don`t think the P51 would of entered service  ,  i think it way way too easy to flip this bird .  seems no warning are in place to say .

``hey pilot im going to flip . 

 

It happens when it looks like the P51 has good speed and energy . 

It reminds me of the 190 stall - flip , we had at the beginning and we had to fight to get it correct to a flyable state . 

My thoughts . Why isnt anyother craft behaving like this . 

Is it well-done and  true to life or is it over done . 

Edited September 27, 2020 by KoN_

[-SF-Disarray]

Without a video example or more details, it is kind of hard to say for sure what is going on here. I do know that the 51 has a tendency to do weird flips and flops if you try to maneuver with fuel in the center tank. This is an observed phenomenon in both the game and the real life plane. This fuel shifts the center of gravity causing the plane to be rather unstable.

[LukeFF]

2 hours ago, KoN_ said:

Ok for a casual gamer this flip over and go into a uncontrolled spin seems crazy over the TOP .

Ive seen so many P51s just flip over on to its back when in a turn fight . Seems this is the only , ONLY craft to actually behave like this in the game .

If this was the case in real life i don`t think the P51 would of entered service  ,  i think it way way too easy to flip this bird .  seems no warning are in place to say .

``hey pilot im going to flip . 

 

Are you serious? The P-51 was expressly prohibited from flying aerobatics when the fuselage tank was full, because it would flip and go into a spin. 

[[DBS]TH0R]

Fuel loadout?

 

Never take more than 40 or 35% fuel. Problem solved.

[357th_KW]

I think part of the issue is that the gun port whistle that used to act as an audible stall warning is gone after the latest patch - really easy to get caught out if you're pulling until you hear that sound.

[KoN_]

On 9/27/2020 at 9:49 PM, LukeFF said:

 

Are you serious? The P-51 was expressly prohibited from flying aerobatics when the fuselage tank was full, because it would flip and go into a spin. 

 

Are you serious ? ? 

Chill dude . 

Stall speed: 100 mph ?? is that correct 

i need to do more testing 

I am quite certain i am not dropping below 100mph in a turn fight with 109s . 

 

Edited September 30, 2020 by KoN_

[DD_Fenrir]

Okay, so...

 

1. Your 1g (i.e straight and level) stall speed (in this case, 100mph you referenced) is not going to be the same as your stall speed under increased g-loads; you essentially make the aircraft weigh more by applying g - ergo your stall speed increases with g. If you are stalling under G you are experiencing an accelerated stall.

 

2. Stalling is not necessarily a function of speed rather, a function of Angle of Attack (AoA), though the two are related. It is possible to stall the wing at any speed. Each wing design and profile has a Critical AoA, that is the angle at which the wing stops being capable of generating lift. In many aircraft you have sufficient elevator authority to pitch the nose beyond the critical AoA at most speeds. Ergo, you could be doing 250, 300 even 400mph but you can still stall the aircraft by being too heavy handed with the aft stick input.

 

3. The Mustang has a laminar flow airfoil; this is a wing profile optimised for low drag at higher speeds, not for generating lots of lift at low airspeed. It is known that the P-51 has poor stall warning characteristics, particularly accelerated stall.

 

4. The Spin occurs after stall due to the following reasons:

• Aircraft not in coordinated flight - if you are turning and not coordinating your turns with corresponding rudder inputs, you will be side-slipping or skidding; this means one wing is being blanked partially by the nose from receiving clean airflow and will generate less lift and stall first, generating a lift gradient across the wings and causing roll.
• Torque forces want to rotate and yaw the aircraft anti-clockwise and to the left - at the stall your aerodynamic control surfaces have lost the majority of their authority and cannot overcome the torque and gyroscopic forces from the engine
• No two wings are absolutely identical, even on the same aircraft and these minor differences can mean the critical AoA is lower on one wing compared to the other. As you approach this AoA, the lower critical AoA wing will stall first, generating a lift gradient across the wings and causing roll.

The upshot? Don't yank the stick like it's a binary input device; you need to guide the aircraft positively but progressively and find the sweet spots which generate the amount of AoA to get the angles you require without exceeding the critical AoA; you'll need to coordinate the rudder to keep the ball centred to ensure you don't exceed the critical AoA on one wing before the other; and you need to understand that these sweet spots are dynamic, that they can change depending on your speed, altitude, and power settings.

 

 

Edited October 2, 2020 by DD_Fenrir

[357th_KW]

From the AFDUs trials of the Mustang III: “There is adequate warning of the high-speed stall in the form of elevator buffeting, followed by tail buffeting.”

 

From the 1944 P-51D manual: “A high-speed stall is preceded by a sharp buffeting at the elevators and wing root ...”

 

This doesn’t really occur in game, but wasn’t an issue when you could hear the gun port whistle to judge how close you were to stalling.

Edited October 1, 2020 by KW_1979

[Floppy_Sock]

I would much rather have the whistling toned down and a buffet warning like the rest of the a/c. Flew the pony yesterday a bit on the training servers and realized the whistle is gone and how much of a crutch it is. Immediately spun in the first corner before I realized the whistle is gone.  

[69th_Mobile_BBQ]

It doesn't matter the speed or fuel load, I've noticed from the day it was released that the Mustang really hates left rolling into a split-S (or most high-bank angle left turns, for that matter).  Chances of snapping it into a death spin are super high.  Seriously, it's almost impossible to fly a coordinated, horizontal, slip ball centered, left turn in the thing without finally "stepping on the ball" until it snaps over.  Test it yourself for proof.

Edited October 1, 2020 by 69th_Mobile_BBQ

[KoN_]

On 10/1/2020 at 10:32 AM, DD_Fenrir said:

Okay, so...

 

1. Your 1g (i.e straight and level) stall speed (in this case, 100mph you referenced) is not going to be the same as your stall speed under increased g-loads; you essentially make the aircraft weigh more by applying g - ergo your stall speed increases with g. If you are stalling under G you are experiencing an accelerated stall.

 

2. Stalling is not necessarily a function of speed rather, a function of Angle of Attack (AoA), though the two are related. It is possible to stall the wing at any speed. Each wing design and profile has a Critical AoA, that is the angle at which the wing stops being capable of generating lift. In many aircraft you have sufficient elevator authority to pitch the nose beyond the critical AoA at most speeds. Ergo, you could be doing 250, 300 even 400mph but you can still stall the aircraft by being too heavy handed with the aft stick input.

 

3. The Mustang has a laminar flow airfoil; this is a wing profile optimised for low drag at higher speeds, not for generating lots of lift at low airspeed. It is known that the P-51 to have poor stall warning characteristics.

 

4. The Spin occurs after stall due to the following reasons:

• Aircraft not in coordinated flight - if you are turning and not coordinating your turns with corresponding rudder inputs, you will be side-slipping or skidding; this means one wing is being blanked partially by the nose from receiving clean airflow and will generate less lift and stall first, generating a lift gradient across the wings and causing roll.
• Torque forces want to rotate and yaw the aircraft anti-clockwise and to the left - at the stall your aerodynamic control surfaces have lost the majority of their authority and cannot overcome the torque and gyroscopic forces from the engine
• No two wings are absolutely identical, even on the same aircraft and these minor differences can mean the critical AoA is lower on one wing compared to the other. As you approach this AoA, the lower critical AoA wing will stall first, generating a lift gradient across the wings and causing roll.

The upshot? Don't yank the stick like it's a binary input device; you need to guide the aircraft positively but progressively and find the sweet spots which generate the amount of AoA to get the angles you require without exceeding the critical AoA; you'll need to coordinate the rudder to keep the ball centred to ensure you don't exceed the critical AoA on one wing before the other; and you need to understand that these sweet spots are dynamic, that they can change depending on your speed, altitude, and power settings.

 

 

Thank you for your input , Guess ill need to add more rudder in a turn.

This all has caught me out so many times , and others too .

Seen many P-51 flip over onto its back trying to keep on 109 tail . 

Took 35% fuel and still got this stall while dog-fighting a 109 that seem to not stall or suffer the same fate . 

The reason i bring this up is i don`t encounter this stall in another flight sim . Hence my question . OP .

18 hours ago, 69th_Mobile_BBQ said:

It doesn't matter the speed or fuel load, I've noticed from the day it was released that the Mustang really hates left rolling into a split-S (or most high-bank angle left turns, for that matter).  Chances of snapping it into a death spin are super high.  Seriously, it's almost impossible to fly a coordinated, horizontal, slip ball centered, left turn in the thing without finally "stepping on the ball" until it snaps over.  Test it yourself for proof.

Its a reason why i bring this up , I don`t see any other il-2 flight model behave like this .other than the  early days on the 190 that just flipped over on a turn . 

Yes the whistle has gone .

No buffeting on elevator . 

I've adjusted my joystick settings to hard curve and see if it will help .

Thank you all for the input . 

[Bremspropeller]

Anybody ever considered dropping a notch of flaps?

The first notch is good for 400mph. You paid for it, why not use it then?

[Blackhawk_FR]

On 10/2/2020 at 3:07 PM, KoN_ said:

Guess ill need to add more rudder in a turn.

 

The slideslip indicator must be centered. That's all. I would say that in a tight turn, you need a bit of left rudder to counter the gyroscopic effect.

But anyway, as soon as you reach the critical AoA, you will stall, and flip over a wing. 

P51 turn pretty well, enough to win against the 109 in a continous turn. But it has the characteristic to not warn you before the stall. The whistle you ear when you start reaching high AoA is a good indicator though. But I'm not sure if it's has been removed with last update (didn't fly 51 since moment, don't remember). 

 

 

6 hours ago, Bremspropeller said:

Anybody ever considered dropping a notch of flaps?

 

I'm not sure the flaps help you, as there is a nose heavy effect when you pull them down. 

[Bremspropeller]

5 minutes ago, JG300_Faucon said:

I'm not sure the flaps help you, as there is a nose heavy effect when you pull them down. 

 

Yeah, but you can trim it away. You'll have to trim all day long in the Mustang anyway...

The flaps do help a duckton. Just as they are and were supposed to.

 

Just don't whiteknuckle the stick.

If people flew the Dora for some time and then re-transitioned to the Mustang, they'd realize how much more you can throw that thing around the sky in wild abandon.

Especially with the flaps out. Below 225 (or was it 240?), you can even drop a second notch, though that one comes with a more pronounced drag-penalty and more nose-digging.

[KoN_]

Whistle has gone yes . 

Drop fuel too 35% 

out turn 109s i find its not happening as blackout comes . 

But not flown for a while since i was flipping this over . 

Gone Russian . lol ?

[FTC_Cule]

On 10/1/2020 at 11:32 AM, DD_Fenrir said:

The Mustang has a laminar flow airfoil; this is a wing profile optimised for low drag at higher speeds, not for generating lots of lift at low airspeed. It is known that the P-51 has poor stall warning characteristics, particularly accelerated stall.

 

The semi-laminar flow airfoil of the P51 delayed it's transition into turbulent regime by only around a 5% margin from what I've read in the literature (lednicer). However one thing which is clear is that their coating of wings and use of flush rivers changed the friction drag dramatically, which empirically has been widely known to contribute to a third of the total plane's drag. The finish is more important than the airfoil in this case in maintaining laminar flow.

 

Of course wings have a bad stall transition because the boundary layer is much less energised and can detach with ease, however, I am under the impression there's more factors contributing to the P51's very aggressive stall, which, in the game, It is my opinion it's extremely light and should even be more aggressive similar to DCS or the original IL-2 1946.

 

 

[Bremspropeller]

5 hours ago, ACG_Cule said:

Of course wings have a bad stall transition because the boundary layer is much less energised and can detach with ease, however, I am under the impression there's more factors contributing to the P51's very aggressive stall, which, in the game, It is my opinion it's extremely light and should even be more aggressive similar to DCS or the original IL-2 1946.

 

On top of that there's also the cusped trailing-edge that was supposed to help in pressure-recovery.

Trouble is, that cusp will help in boundary-layer separation due to precisely this adverse pressure-gradient.