Flight Model Discussion

[Aware29]

Just wanted to start a discussion on people’s thoughts and observations on the flight model. 
One thing that immediately jumped out to me during my testing is the proverse yaw. In low to medium AoAs the aircraft has a pretty strong proverse yaw response. Which I found a bit surprising, considering the MiG 29 uses ailerons and a bit of differential stabilizer to roll the aircraft. I read in the real world manual about the ailerons being up 5 degrees from neutral to help reduce adverse yaw, but nothing about eliminating it or proverse yaw. I’m not saying this is unrealistic, as I don’t know, just that I would think the aircraft would have adverse yaw instead of proverse. 
Anyone out there that perhaps knows any real MiG drivers that can ask if this is indeed accurate? Or if someone has a manual that describes this characteristic?

I saw GVad the Pilots YouTube video about the flight model. Seems to be slightly underperforming in high speed flight as well?

All in all it does feel great to fly! Doing tail slides is fun and it seems to behave just like how you see in real videos from airshows 

Edited 2 hours ago by Aware29

[YoYo]

You're probably talking about the before-1 patch video, here's the after video, it looks pretty good:

 

[AeriaGloria]

The only thing I notice it’s turning behavior. According to charts it should hit sustained 9 G right at 900 kmh, and maintain max G until supersonic speed. Right now it stops maintaining 9 G will before supersonic speed

[NineLine]

1 hour ago, AeriaGloria said:

The only thing I notice it’s turning behavior. According to charts it should hit sustained 9 G right at 900 kmh, and maintain max G until supersonic speed. Right now it stops maintaining 9 G will before supersonic speed

Sadly, this is a very vague comment; without knowing drag index, gross weight, altitude, and throttle setting, we really can't say if there is an issue or now, as well as what charts you are referencing, etc. 

[AeriaGloria]

1 hour ago, NineLine said:

Sadly, this is a very vague comment; without knowing drag index, gross weight, altitude, and throttle setting, we really can't say if there is an issue or now, as well as what charts you are referencing, etc. 

I am referencing German TO-1 that can be purchased from Amazon and also appears in the L-18 manual which can also be purchased on Amazon, and most importantly the instantaneous G chart from the same German TO-1 that can be purchased on Amazon. As well as many comments in practical aerodynamics saying it is not until you hit transonic speeds that the elevator loses efficiency and stops you from pulling max G. This sustained turn chart shows both drag and gross weight and so should be able to atleast hit those numbers. The instantaneous G chart doesn’t say exactly drag and weight just “clean or with missiles”, but if it’s like every other single chart it is for 2x R-73, 4x pylons, and 13,000 kg weight with approximately 1,500 kg fuel. Either way it should hit these numbers at some point in the flight envelope. The creators of the chart clearly thought it correct enough for a wide enough range to say “clean or with missile load CG 25.5%”
 

Notice how at low altitudes it has no  problem hitting max G until is just past Mach 0.85 This is also the exact reason the ARU system is tuned to start giving authority back at 1200 kmh. 
 

On second look it does seem to hit these numbers pretty well for the instantaneous chart right at sea level, but it does seem to be under doing max G at the 3-5 km lines in game. I do not about the sustained chart 

 

Edited 3 hours ago by AeriaGloria

[Cgjunk2]

8 hours ago, Aware29 said:

Just wanted to start a discussion on people’s thoughts and observations on the flight model. 
One thing that immediately jumped out to me during my testing is the proverse yaw. In low to medium AoAs the aircraft has a pretty strong proverse yaw response. Which I found a bit surprising, considering the MiG 29 uses spoilers and a bit of differential stabilizer to roll the aircraft. I read in the real world manual about the spoilers being up 5 degrees from neutral to help reduce adverse yaw, but nothing about eliminating it or proverse yaw. I’m not saying this is unrealistic, as I don’t know, just that I would think the aircraft would have adverse yaw instead of proverse. 
Anyone out there that perhaps knows any real MiG drivers that can ask if this is indeed accurate? Or if someone has a manual that describes this characteristic?

I saw GVad the Pilots YouTube video about the flight model. Seems to be slightly underperforming in high speed flight as well?

All in all it does feel great to fly! Doing tail slides is fun and it seems to behave just like how you see in real videos from airshows 

I don’t know if I’m missing something or if I’m losing it, but the Mig29 doesn’t control roll through spoilers.  It uses ailerons.  

Also, I haven’t heard the word “proverse” being used to described yaw tendencies.  Generally speaking, only adverse yaw occurs when ailerons are responsible for commanding the roll.  Ailerons will always cause induced drag on the wing that rises because anything being lifted results in more drag.  That drag “pulls” the lifting wing backwards, which is the same thing as saying it yaws the airplane opposite of the roll direction.   I know aerodynamics are complicated (especially on fighters), but I don’t think it possible for ailerons (being used on their own) to induce a yaw into the roll direction.  

The “proverse” yaw you’re seeing is probably the rudder input being commanded by the FCS/stabilization system.  Most large/heavy airplanes have some sort of system that commands inside rudder to cancel out the adverse yaw and keep the turn coordinated.

Recently I did see someone comment about both ailerons both resting at a positive angle, but for the purpose increasing the washout effect of the wing as a whole (not to address adverse yaw). Washout describes the amount of twist built into a wing.  With the twist resulting in a wing that has less AOA near the tips, than it does near the wing root, which is meant to guarantee the root stalls before the outboard portion of the wing, which theoretically results in milder/more controllable stall charcteristics. Setting those ailerons to have the positive angle sounds like a neat little trick the designers used to simplify the process of producing the wing.  As I would imagine that allows them to build a flat wing instead of one with a twist.  Or say the wings are built with washout, using the ailerons in such a way could fine tune the intended effects if the designed washout twist was found to be insufficient during flight testing.

Edited 3 hours ago by Cgjunk2

[AeriaGloria]

5 minutes ago, Cgjunk2 said:

I don’t if I’m missing something or if I’m losing it, but the Mig29 doesn’t control roll through spoilers.  It uses ailerons.  

Also, I haven’t heard the word “proverse” being used to described yaw tendencies.  Generally speaking, adverse yaw occurs when ailerons are responsible for commanding the roll.  Ailerons will always cause induced drag on the wing that rises because anything being lifted has more lift, and therefore more drag.  That drag “pulls” the lifting wing backwards, which is the same thing as saying it yaws the airplane opposite of the roll direction.   I know aerodynamics are complicated (especially on fighters), but I don’t think it possible for ailerons (being used on their own) to induce a yaw into the roll direction.  

The “proverse” yaw you’re seeing is probably the rudder input being commanded by the FCS/stabilazation system.  Most large/heavy airplanes have some sort of system that commands inside rudder to cancel out the adverse yaw and keep the turn coordinated.

Recently I did see someone comment about both ailerons both resting at a positive angle for the purpose increasing the washout effect of the wing as a whole.  Washout describes the amount if twist built into a wing.  With the twist resulting in a wing that has less AOA near the tips, than it does near the wing root, which is meant to guarantee the root stalls before the outboard portion of the wing, which theoretically allow the ailerons to remain effective into the  stall.  Setting those ailerons to have the positive angle sounds like a neat little trick the designers used to simplify the process of producing the wing.  As I would imagine that allows them to build a flat wing instead of one with a twist.

1. It does show proverse yaw, it is just the opposite of adverse yaw. Planes that use spoilers may experience this, or on this case ailerons that are tilted up. 
 

2. the rudders do not move with the ailerons unless you move the pedals. IRL it would BUT only at high AOA, such as 18-26 degrees. It may be implemented eventually, but at normal AOAs it will not happen 

3. The ailerons do give slight washout effect, however the wing already exhibits 4.6 degrees of washout. If you read the practical aerodynamics manual, they will mention that the ailerons are 5 degrees up to improve high AOA roll control. 

[Cgjunk2]

4 minutes ago, AeriaGloria said:

1. It does show proverse yaw, it is just the opposite of adverse yaw. Planes that use spoilers may experience this, or on this case ailerons that are tilted up. 
 

2. the rudders do not move with the ailerons unless you move the pedals. IRL it would BUT only at high AOA, such as 18-26 degrees. It may be implemented eventually, but at normal AOAs it will not happen 

3. The ailerons do give slight washout effect, however the wing already exhibits 4.6 degrees of washout. If you read the practical aerodynamics manual, they will mention that the ailerons are 5 degrees up to improve high AOA roll control. 

1.  That is very interesting. I hadn’t thought about the possible effects of the aileron being tilted up on yaw tendencies when rolling. But,   I’ll be honest, I’m having a time understanding what factors go into negating the relative difference in lift/drag on wings being commanded to roll.   Not saying that it doesn’t do what you say, but just that aerodynamics are complicated and I cant wrap my head around it.

 

2. So the rudders aren’t used at all in the simulation’s FCS currently?  I could have sworn I’ve seen and felt them moving around.  
 

 

[Aware29]

18 minutes ago, Cgjunk2 said:

I don’t know if I’m missing something or if I’m losing it, but the Mig29 doesn’t control roll through spoilers.  It uses ailerons.  

Also, I haven’t heard the word “proverse” being used to described yaw tendencies.  Generally speaking, only adverse yaw occurs when ailerons are responsible for commanding the roll.  Ailerons will always cause induced drag on the wing that rises because anything being lifted results in more drag.  That drag “pulls” the lifting wing backwards, which is the same thing as saying it yaws the airplane opposite of the roll direction.   I know aerodynamics are complicated (especially on fighters), but I don’t think it possible for ailerons (being used on their own) to induce a yaw into the roll direction.  

The “proverse” yaw you’re seeing is probably the rudder input being commanded by the FCS/stabilization system.  Most large/heavy airplanes have some sort of system that commands inside rudder to cancel out the adverse yaw and keep the turn coordinated.

Recently I did see someone comment about both ailerons both resting at a positive angle, but for the purpose increasing the washout effect of the wing as a whole (not to address adverse yaw). Washout describes the amount of twist built into a wing.  With the twist resulting in a wing that has less AOA near the tips, than it does near the wing root, which is meant to guarantee the root stalls before the outboard portion of the wing, which theoretically results in milder/more controllable stall charcteristics. Setting those ailerons to have the positive angle sounds like a neat little trick the designers used to simplify the process of producing the wing.  As I would imagine that allows them to build a flat wing instead of one with a twist.  Or say the wings are built with washout, using the ailerons in such a way could fine tune the intended effects if the designed washout twist was found to be insufficient during flight testing.

Wow, forgive me haha. Idk why I wrote spoilers instead of ailerons. I must have had spoilers on my mind while typing because aircraft that use spoilers for roll, like the F14, tend to see proverse yaw. I edited my post to correct yet. Proverse yaw is the opposite of adverse. When making a lateral input, the nose will swing INTO the direction of the turn. Instead of AWAY like with adverse yaw. Which is why I’m puzzled as to why the MiG demonstrates proverse yaw. It’s not from the rudders because if you look in external view you’ll see that the rudders have zero movement when rolling with the stick 

And I’m not saying the real MiG doesn’t demonstrate proverse yaw, I’ve never flown one. I’m just surprised that ours does in game because everything I know about aerodynamics tells me that it shouldn’t. So I’d love to hear from people more knowledgeable than me as to if it’s correct. I’d be very interested in knowing why it does 

4 minutes ago, Cgjunk2 said:

. So the rudders aren’t used at all in the simulation’s FCS currently?  I could have sworn I’ve seen and felt them moving around.  

I’ve done a good amount of testing on this. You can barely see them move with big stick movements, like 2-3 degrees, and only in a dampening capacity it seems. They’ll work against the direction of roll. But you have to really zoom in to see them work

[Aware29]

19 minutes ago, AeriaGloria said:

The ailerons do give slight washout effect, however the wing already exhibits 4.6 degrees of washout. If you read the practical aerodynamics manual, they will mention that the ailerons are 5 degrees up to improve high AOA roll control.

Where can I find the practical aerodynamics manual?

[AeriaGloria]

23 minutes ago, Cgjunk2 said:

1.  That is very interesting. I hadn’t thought about the possible effects of the aileron being tilted up on yaw tendencies when rolling. But,   I’ll be honest, I’m having a time understanding what factors go into negating the relative difference in lift/drag on wings being commanded to roll.   Not saying that it doesn’t do what you say, but just that aerodynamics are complicated and I cant wrap my head around it.

 

2. So the rudders aren’t used at all in the simulation’s FCS currently?  I could have sworn I’ve seen and felt them moving around.  
 

 

Think of it like this. Ailerons are 5 degrees up. 
 

Let’s say I move the stick so the ailerons deflect 5 degrees. 
 

One aileron is now level with trailing edge (adding lift and drag) 

The other aileron would now be 10 degrees above the trailing edge, reducing the lift and thus lift induced drag of that wing 

 

The rudders have dampener actuators to be part of the dampening system. But they do not move with the ailerons, and when it is implemented they will only move up to 8 degrees with the ailerons only at high AOA. 

[Aware29]

6 minutes ago, AeriaGloria said:

One aileron is now level with trailing edge (adding lift and drag) 

The other aileron would now be 10 degrees above the trailing edge, reducing the lift and thus lift induced drag of that wing

Right, and in that example you made, you would get adverse yaw. Let’s say it’s a turn to the left. Left aileron is up 10 degrees, reducing lift and induced drag. The right aileron is neutral, so more lift and thus induced drag on the right wing. That drag will want to suck that right wing back, thus yawing the nose to the right with it. Adverse yaw. Now, the adverse yaw wouldn’t be as much as if the aileron was a few degrees below the wing, but it still should be there. That’s why they made the ailerons rest at 5 degrees up. In the GAF manual it says that they are 5 degrees up to “prevent excessive adverse yaw during rolls” it doesn’t say anything about eliminating it or inducing proverse yaw

[AeriaGloria]

26 minutes ago, Aware29 said:

Right, and in that example you made, you would get adverse yaw. Let’s say it’s a turn to the left. Left aileron is up 10 degrees, reducing lift and induced drag. The right aileron is neutral, so more lift and thus induced drag on the right wing. That drag will want to suck that right wing back, thus yawing the nose to the right with it. Adverse yaw. Now, the adverse yaw wouldn’t be as much as if the aileron was a few degrees below the wing, but it still should be there. That’s why they made the ailerons rest at 5 degrees up. In the GAF manual it says that they are 5 degrees up to “prevent excessive adverse yaw during rolls” it doesn’t say anything about eliminating it or inducing proverse yaw

The question is the aileron moving from 5-10 degrees reducing drag more then the aileron moving from 5 degrees to level with trailing edge is increasing it. At the very least, it is reducing the natural adverse yaw tendency as it essentially acts as differential (aileron that moves up moved more up then down aileron moves down.) Interestingly the trailing edge of the aileron is also tilted down 10 degrees to help neutralize the force on the hinge at neutral position. 
 

We also have the influence of stabilizer scissors at 7-8.7 degrees AOA. As it is stable the elevators needs to constantly push tail down. When scissors from aileron input, the inside stabilizer in the turn is moving further up and also adding more drag while the outside stabilizer is moving down and decreasing drag. 
 

But of course, it’s harder to tell proverse/adverse yaw at AOA above 7-8.7, and the designers made every effort to reduce the natural adverse yaw at high AOAs 

Somehow though the scissoring elevators produces adverse yaw at high AOAs, which is why it’s disabled when LEFs come down. 

Edited 1 hour ago by AeriaGloria

[Aware29]

20 minutes ago, AeriaGloria said:

The question is the aileron moving from 5-10 degrees reducing drag more then the aileron moving from 5 degrees to level with trailing edge is increasing it

If the left aileron going up reduced drag more than the right aileron going to neutral, you should still see adverse yaw id think. Think about it. The left wing would see less drag than the right wing, thus wanting to move forward more. That would give a right yawing force. But then you have to think about the parasite drag from the left aileron sticking up into the airstream. That would cause some drag on the left wing. 

But even when making full stick deflections you see proverse yaw. And in that situation the upward going wing sees the aileron move down below neutral. 

I have thought about the stabilators movement during rolls possibly causing the proverse yaw. That very much could be it. 

And because its text and things are lost, I’m not trying to argue or anything! Just having a nice conversation! In case that wasn’t clear 

Edited 1 hour ago by Aware29

[Cgjunk2]

32 minutes ago, AeriaGloria said:

The question is the aileron moving from 5-10 degrees reducing drag more then the aileron moving from 5 degrees to level with trailing edge is increasing it. At the very least, it is reducing the natural adverse yaw tendency as it essentially acts as differential (aileron that moves up moved more up then down aileron moves down.) Interestingly the trailing edge of the aileron is also tilted down 10 degrees to help neutralize the force on the hinge at neutral position. 
 

We also have the influence of stabilizer scissors at 7-8.7 degrees AOA. As it is stable the elevators needs to constantly push tail down. When scissors from aileron input, the inside stabilizer in the turn is moving further up and also adding more drag while the outside stabilizer is moving down and decreasing drag. 
 

But of course, it’s harder to tell proverse/adverse yaw at AOA above 7-8.7, and the designers made every effort to reduce the natural adverse yaw at high AOAs 

Somehow though the scissoring elevators produces adverse yaw at high AOAs, which is why it’s disabled when LEFs come down. 

Thanks for the explanation.  I won’t say I’ve fully digested it yet lol, but I have a better understanding of the other factors involved.  
 

Edit to add: it’s a bit mindblowing to think, not only of the interplay of the different parts of the control architecture, but of how that interplay changes in different flight regimes.   It’s quite an orchestra that aerospace engineers are putting together! 

Edited 1 hour ago by Cgjunk2

[AeriaGloria]

27 minutes ago, Aware29 said:

If the left aileron going up reduced drag more than the right aileron going to neutral, you should still see adverse yaw id think. Think about it. The left wing would see less drag than the right wing, thus wanting to move forward more. That would give a right yawing force. But then you have to think about the parasite drag from the left aileron sticking up into the airstream. That would cause some drag on the left wing. 

But even when making full stick deflections you see proverse yaw. And in that situation the upward going wing sees the aileron move down below neutral. 

I have thought about the stabilators movement during rolls possibly causing the proverse yaw. That very much could be it. 

And because its text and things are lost, I’m not trying to argue or anything! Just having a nice conversation! In case that wasn’t clear 

 Brother, we would need wind tunnel to figure this out

[Aware29]

16 minutes ago, AeriaGloria said:

 Brother, we would need wind tunnel to figure this out

Haha true. I’d love to be able to ask someone who flew the real jet