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F-86 no rudder input needed to maintain coordinated turns.


SMH

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F-5 no rudder input needed to maintain coordinated turns. Even when turning as hard as you can, the ball stays perfectly centered without requiring any rudder input. That can't be right, can it? F-5 and MiG-15 also seem to have this issue now. 

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Not an 'issue' on the F-5 and an F-86 manual states;

 

....inherent stability of the plane is such that coordinated maneuvers can be made with minimum use of rudder.

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LOL...I remember when the F86 was released. This was a big complaint among everyone who purchased it. But then it turned out that it was accurate to the plane. F-5 also. Same scenario. 

 

 I think that the Mig15 has such a big ass rudder that it probably required minimal movement for turns. I have not flown that plane in a few years. 


Edited by Zimmerdylan
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On 5/6/2021 at 2:48 PM, bbrz said:

Not an 'issue' on the F-5 and an F-86 manual states;

 

....inherent stability of the plane is such that coordinated maneuvers can be made with minimum use of rudder.


*Minimum* of rudder. Not *no* rudder. It's physically impossible for a banking aircraft to not exhibit adverse yaw. The only planes you shouldn't have to use rudder to coordinate turns in are modern fly-by-wire aircraft.

What's the official ED position on this? These flight models *were* good before. Now I feel like I'm flying a lesser sim. 

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20 minutes ago, SMH said:


*Minimum* of rudder. Not *no* rudder. It's physically impossible for a banking aircraft to not exhibit adverse yaw. 

 

But that's what differential and frise ailerons were invented for, weren't they? To make it possible, even before fly-by-wire era. 

I don't know what ailerons Sabre uses, though.

 

The bigger question is was there really any recent change in FM? Most of the ex-Belsimtek-developed modules seem to be pretty much abandoned in recent years (so don't expect any "officla position" on this by the way) and thus I doubt anythng was done to them in this regard. I also don't remember noticing adverse yaw in the Sabre when I got it in 2014, so maybe it was always like this? Can't be bothered to install legacy DCS 1.5.6 to check.

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On 5/22/2021 at 4:46 AM, Art-J said:

 

But that's what differential and frise ailerons were invented for, weren't they? To make it possible, even before fly-by-wire era. 

I don't know what ailerons Sabre uses, though.

 

The bigger question is was there really any recent change in FM? Most of the ex-Belsimtek-developed modules seem to be pretty much abandoned in recent years (so don't expect any "officla position" on this by the way) and thus I doubt anythng was done to them in this regard. I also don't remember noticing adverse yaw in the Sabre when I got it in 2014, so maybe it was always like this? Can't be bothered to install legacy DCS 1.5.6 to check.


No, there's no magic ailerons. The outer wing in the turn goes faster, so it makes more drag, and wants to yaw the nose outward against the turn. 

I can't say for the Sabre for sure because I didn't fly it a lot till recently but I'm sure the F-5 and MiG-15 used to have adverse yaw and now there's nothing. Way less fun to fly now. I feel like I'm in the Hornet. 

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On 5/22/2021 at 10:14 AM, SMH said:


 It's physically impossible for a banking aircraft to not exhibit adverse yaw. 
 

Incorrect. Ever heard e.g. about roll spoilers?

2 minutes ago, SMH said:


The outer wing in the turn goes faster, so it makes more drag, and wants to yaw the nose outward against the turn. 

Differential ailerons are countering exactly this problem. 


Edited by bbrz

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3 minutes ago, bbrz said:

Incorrect. Ever heard e.g. about roll spoilers?

Differential ailerons are countering exactly this problem. 

 

You're just making stuff up. None of this is on these planes.

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2 hours ago, SMH said:

You're just making stuff up. None of this is on these planes.

Your ignorance doesn't make things you're ignorant about disappear. For instance, Earth is not flat.

Differential ailerons were used since interbellum.


Edited by m4ti140
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On 5/5/2021 at 10:17 AM, SMH said:

F-5 no rudder input needed to maintain coordinated turns. Even when turning as hard as you can, the ball stays perfectly centered without requiring any rudder input. That can't be right, can it? F-5 and MiG-15 also seem to have this issue now. 

https://pilotworkshop.com/tips/rudder_coordinated_flight/

 

Quote

When entering a turn, you apply a given amount of aileron. After you have established the desired bank, you neutralize the ailerons, that is the time you also neutralize the rudder. Now when it is time to roll out of the turn, the opposite happens. You again use aileron, so you also need rudder to counteract that adverse yaw.

In a properly rigged airplane, you should not need to be holding any rudder during a shallow or medium-banked turn.

 


Edited by Machalot

"Subsonic is below Mach 1, supersonic is up to Mach 5. Above Mach 5 is hypersonic. And reentry from space, well, that's like Mach a lot."

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What has a standard GA aircraft in common with an F-5?

 

FYI, that's from a T-38 manual:  

Aileron deflection produces yaw in the direction of roll (favorable yaw).  Rudder is not required to produce coordinated turns.

 

Btw. not even the A-10 requires any manual rudder input to achieve turn coordination.


Edited by bbrz

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On 5/26/2021 at 6:12 PM, SMH said:


The outer wing in the turn goes faster, so it makes more drag, and wants to yaw the nose outward against the turn. 

 

Close, but no cigar.  The up-going wing has a down-moving aileron, which raises the AoA of that section of the wing, creating more lift which in turn creates more drag, The down-going wing has an up-moving aileron which lowers the AoA of that section of the wing which creates less lift and hence less drag. 

 

It is the different levels of drag yawing the nose towards the outside of the turn, nothing to do with wings going faster or slower. 

 

This is countered in most 'modern' (like, since the 1930s) aircraft with differential ailerons, where the up-moving aileron moves more than the down-moving one, thus creating more drag on the down-moving wing, and partially eliminating adverse yaw conditions during most flight regimes. 

 

It is also why you don't use the ailerons at or very near stall conditions (i.e. high AoA), but maintain directional control with the rudder, as an aileron induced increased AoA can stall the outward section of the up-going wing, which then very rapidly becomes the down-going wing!

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44 minutes ago, Frederf said:

The idea that aileron drag produces exactly the right yaw to exactly coordinate all turns of any rate across wide range of Mach in all of these airplanes is really hard to believe.

Yes, but so far we don't have any data on just how "exact" it is and across what range of flight conditions, at least in this thread.

"Subsonic is below Mach 1, supersonic is up to Mach 5. Above Mach 5 is hypersonic. And reentry from space, well, that's like Mach a lot."

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10 hours ago, Machalot said:

Yes, but so far we don't have any data on just how "exact" it is and across what range of flight conditions, at least in this thread.

Try turning in these aircraft. The ball goes hard to center. Tight, loose, slow, fast, doesn't matter, even with a thrust imbalance in the F-5 or A-10C, as soon as you start turning the ball magically moves to center. (Even when your thrust imbalance should push it out. Like, a thrust imbalance shouldn't help turn in BOTH directions, right?)

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I flew years ago as passenger in TS-11 training jet. Since i just become "3-rd class glider pilot" - I thought that I know everything about flying. I was amazed that pilot made turns only using just ailerons. In glider you start a turn from a "leg" . Rudder - aileron always.

"It's not a glider son" I heard

Wingspan is much smaller also ailerons movement is asymmetrical. If you want to study the reasons they are all here:
Roskam "Airplane design vol.6"
Roskam "Airplane dynamics and performance"
Anderson "Aircraft performance and design"
Torenbeek "Synthesis of subsonic airplane design" 

and:
Bernard Etkin "Dynamics of flight - Stability and control"

@SMH - All has good reasons. Complement all Info needed - than produce a post. Experience in arcade sims is not enough. It's not a War Thunder


Edited by 303_Kermit
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On 5/28/2021 at 5:38 PM, Frederf said:

The idea that aileron drag produces exactly the right yaw to exactly coordinate all turns of any rate across wide range of Mach in all of these airplanes is really hard to believe.

 

Aileron drag itself no, not necessarily.But it would vary automatically with speed and amount of control surface deflection due to its nature, so if the aileron system is well-rigged/constructed , it might go a long way in helping with it. 

 Also these aircraft  may have various forms of mechanisms or stability augmentation systems like yaw dampers, mechanical or non-mechanical ARI etc, that help with coordination without having to add manual rudder, at least within a certain AOA range. 

 

Some you can switch off, others probably not, however even in a simulation like DCS the abnormal system simulation may be lacking, I wouldn’t be surprised at all.

But also, despite their marketing claims , some parts of their FMs are likely not as accurate as ED likes to portray them. For a multitude of reasons. 

But my personal opinion , in regards to this specific issue , at least for the F-5 and A-10 , I think it’s simulated correctly, as least for normal operating conditions 

For the F-86 and Mig-15 I can‘t say , since I simply don’t know enough about their systems and real world flight characteristics.

 

regards,

 

 Snappy 

 

p.s. Kermit ist right though in his point, if you want to get something changed, provide solid information from flight manuals or other valid sources and not blanket claims like „ all aircraft exhibit adverse yaw behavior“.

 


Edited by Snappy
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