[FIXED INTERNALLY] Wind not accounted for in flight model and display.

That's a contradiction. Climb change with the wind. When headwinding, the wind speed is added to that of the aircraft speed, this is because aerodynamically the lift is produced with the advance of the wings in the air. More lift = more climb, more climb = more ft/min and vice versa. So an aircraft with the tailwind will climb slowly.

No

Lift is created from the wings moving through the air so the only thing that matters is the relative motion difference between the air and the aircraft. The ground speed has nothing to do with it. And aircraft could be flying at 200 knots airspeed in a 200 knot headwind with a ground speed of 0 and it would be creating just as much lift as if it was flying at 200 knots with a 200 knot tailwind. The climb rate of the aircraft in both cases would be the same. The distance traveled during the climb would be different. But the climb rate, as in how many feet per minute or meters per second would be identical.

Lol, this whole thread has gone nuts!

Are we really living in a time-space where several people argue about SIMPLE FACTS OF LIFE on a forum, rather than going on ANY website or ANY book and read about wind and airplanes?

Jeez. Unless you are trolling, you are pretty pathetic really. :doh:

I'm pretty well versed on aerodynamics, thank you very much... ????

 

The wind is just a vector being added to the aerodynamic forces on an aircraft. It affects the amount of sideslip required, lift produced and a host of other effects. It determines not only groundspeed and track but also the performance of the aircraft. The effects may have been exaggerated somewhat in DCS (and I assume that is what they tweaked) but it certainly affects all aspects of the FM. On the ground and in the air.

So much for being "well versed in aerodynamics" lol.

Let me get my pilot's license and burn it, obviously I've been risking my life for the past 16 years flying into headwinds and tailwinds without knowing the high risk of stalling or overspeeding :megalol:

Objection, your honor. The inertia comes into play. Lets say your aircraft has a stall speed of 70kts. Now you fly your aircraft at 100kts in a 50kts laminar headwind, guess what happens when you perform a 180° turn, if you perform that turn quickly, but without changing your pitch.

 

Fox

Objection overruled! :D

What happens is this: nothing.

I keep flying perfectly safe at 100kts IAS.

My ground speed will be 100kts IAS + 50Kts GS = 150 kts ground speed as opposed to 50Kts GS when I was flying with a headwind.

That's it.

P.S. the onyl reason why I would stall is I made that turn *so* quick that I pulled too many Gs and dropped my speed below stall speed, or my AoA was so high that I stalled. But all of this has nothing to do with wind, so...

Lol, this whole thread has gone nuts!

Are we really living in a time-space where several people argue about SIMPLE FACTS OF LIFE on a forum, rather than going on ANY website or ANY book and read about wind and airplanes?

Jeez. Unless you are trolling, you are pretty pathetic really.

Yep it boggles my mind also. Lol.

Objection, your honor. The inertia comes into play. Lets say your aircraft has a stall speed of 70kts. Now you fly your aircraft at 100kts in a 50kts laminar headwind, guess what happens when you perform a 180° turn, if you perform that turn quickly, but without changing your pitch.

Fox

What happens is this: nothing.

I keep flying perfectly safe at 100kts IAS.

My ground speed will be 100kts IAS + 50Kts GS = 150 kts ground speed as opposed to 50Kts GS when I was flying with a headwind.

That's it.

P.S. the onyl reason why I would stall is I made that turn *so* quick that I pulled too many Gs and dropped my speed below stall speed, or my AoA was so high that I stalled. But all of this has nothing to do with wind, so...

Now give me a chance to explain better why I replied Foxromeo that the plane stalled. Fox is talking about inertia and a "quick turn". Let's do this, take the quick turn off and say that magically you are hit by the tilwind in an instant, i know it is no longer constant wind but let's pretend it is, what happens? it happens that until the wind has overcome your inertia and has dragged you at its own speed, YOU WILL STALL! I know this in reality occurs only with gusts of wind but the example was to make it clear that the constant wind affects the flight when you try to oppose its direction. The wind is a moving mass, therefore it exerts a force, this is physical! The wind exists because the air does not follow the direction of the earth's rotation (for various reasons that i don't explain and you already know) and affects the aircraft because the mass of the plane is not attracted in the direction of the wind but towards the center of the planet! this is physical! I've been trying to say this for a day.

Ok, I give up. It's apparently useless trying to explain anything to you.

Concerning climb. I wrote exactly the opposite!!!

One more time: If there's a 100kts head or tailwind doesn't matter concerning climb performance. Climb rate will be the same at 200kts groundspeed and at 400kts groundspeed.

Isn't it strange that most aircraft in DCS and in all other flightsims are fundamentally wrong in your opinion.

For the last time, your video shows that wind affects the airplane only in relationship to the ground, but I know, that's not what you want to read.

Bye.

This looks like quality trolling to me now which really has absolutely no place in the bugs section. However, I will make one more post that I hope will help anyone who is genuinely interested in learning how planes fly.

Horizontal wind has nothing to do with climb rate. The only things that can affect climb rate are drag, thrust, gravity, and vertical wind (updraft/downdraft).

In the example given by bbrz, the reason the aircraft would be lower over the obstacle in a tailwind condition is because it has less time to climb before reaching the obstacle due to higher ground speed which is the only thing the wind is affecting. The climb rate is exactly the same.

Things going from side to side do not affect things up and down.

And remember, the only things that affect indicated airspeed are drag, thrust, and air density. Wind cannot change neither drag nor thrust, and we're not talking about changing air density. As wind hits the aircraft from behind it is met with the very same opposing force as static air is met with, and since drag does not change the aircraft is propelled at the very same indicated airspeed, only ground speed has changed.

No, it influences the landing as the aircraft will have to correct it's direction in relation with the ground in order to avoid veering off track ones the tires hit the ground. The flight of the aircraft won't be affected at all, i.e. aircraft performance stays unchanged.

Only gusts of wind & turbulence will impact and be felt by an aircraft in flight.

In short steady state winds only impacts an aircraft in 3 ways:

Ground track

Ground speed

Range (over ground, obviously)

Flight characteristics & performance stays unchanged

I answer everyone for the last time.

Mar

I'm not trolling anyone, if you are afraid of confrontation here we can always open another discussion.

Hummingbird

You also don't understand. Forget the earth. If the pilot has to oppose the direction of the wind, this means that the wind is a force, the only way for the aircraft not to "feel" the wind is to get carried away by it in its direction, ground or not, nothing changes.

bbrz

Why do you think I posted the DCS video? simply because it demonstrates what I say as well as all the crosswind landing videos.

Again climb. The example you did on the object at the end of the runway is right, this is exactly what contradicts you when you say that the climbing performances are the same both with headwind and with tailwind. If they were the same, the plane would have been at the same altitude. Of course, you know how the climb is measured? do you know it's a speed like m/s?

It tells you how quickly a plane go up, it is a vertical speed, and if at the end of the runway with tailwind you are lower than the headwind, this means that for the same time you went up less!

Jeez. Unless you are trolling, you are pretty pathetic really.

nope you are pathetic

I'm writing what I tried to say here for the last time since someone thinks I am a troll. I don't think you are a troll but honestly i would have preferred it because if you don't understand the most basic things...

What I know and what I think.

First, what is the wind and how it is generated. It is a displacement of air relative to the ground. It is measurable only, I repeat, ONLY when it moves in a different direction from the earth's rotation. When the air moves together with the earth there's no wind, I repeat there is NO wind.

And now comes the inertia. I think you all know the example of the man moving on the train. The example says that if you are dragged at a certain speed, then a certain motion, your body will keep the motion itself. This happens to the plane in the constant wind, which is why it is said that it does not affect the aerodynamic characteristics, as well as the man on the train that moves with uniform motion does not feel any acceleration. But what if the man tries to run in the same direction as the train? seeing how many of you think i suppose you don't know it. I make it easier, what happens if the man make a small jump? obviously you will say that he falls in the same point of the train, this is right. What if he makes a jump of a hundred meters? Well it happens that it doesn't even land on the train that meanwhile will have passed him! and why does this happen? it happens because gravity is a constant acceleration that bring you down and also the wind outside the train in not moving. What does all this have to do with flight. Do you think the plane is a magical thing without mass that is not attracted to the ground in a constant way? Same thing applies to the wind when it drags an aircraft, when the pilot decides to oppose the direction of the wind, he will have to consider it as a force vector therefore definitively the constant wind affects the flight.

Just to be clear for those who are slow to understand. The wind, constant or not, in no way alters the aerodynamic properties, it do not change the CL or the CD, the only thing that does is interact in the overall flight.

I hope someone, moderator or expert can help me, maybe we could open a new discussion.

I think i give up

Again climb. The example you did on the object at the end of the runway is right, this is exactly what contradicts you when you say that the climbing performances are the same both with headwind and with tailwind. If they were the same, the plane would have been at the same altitude. Of course, you know how the climb is measured? do you know it's a speed like m/s?

It tells you how quickly a plane go up, it is a vertical speed, and if at the end of the runway with tailwind you are lower than the headwind, this means that for the same time you went up less!!

Sorry Falcon, but no.

I understand your logic but it’s not correct and doesn’t apply to the specific aviation terminology we are using.

The aircraft height at the end of the runway has nothing to do with its climb performance being effected by the wind. It just means that it reached the end of the runway sooner or later because of the wind direction.

If it was taking off in a headwind it would get airborne sooner because it would require less acceleration time, and so it would use less runway and have more time to climb before it reaches the far end of the runway. = Higher

In a tailwind takeoff the aircraft will use more runway to get airborne and it will reach the far end of the runway sooner because of the tailwind. = Lower

BUT in both cases the Climb Performance of the aircraft, that is to say the ft/min of climb rate that the aircraft achieves once it leaves the ground will be the same. The only difference is the time taken to reach the end of the runway. If instead of distance (length of runway) you measure how high both the aircraft are after they got airborne after one minute you would find that they are the same.

Doesn’t matter if you’re flying into wind, across wind or tail wind, if an aircraft can attain 2000ft/min of climb it will do that in any wind. The climb rate will be the same, the time to reach the end of the runway will be different. This is not a change in climb performance.

Nobody here has been trying to argue that wind doesn’t effect an aircrafts ground speed and ground track. We have ALL been saying that from the beginning. If that’s what you’re trying to get across then we agree. But steady state wind does not effect the performance (airspeed, climb rate, stall speed etc etc) of an aircraft. These are fundamental inarguable facts of aviation.

The Falcon,

Just separate earth from air.

The only time you need to relate to each other is for takeoff, navigation and landing purposes only.

Other than that you fly relative to this air your in at the time. There is turbulence in that air that with bump you around from time to time.

When you takeoff it's (Into the wind)

Otherwise you are trying to get into that (moving air) that's travelling the other way at 30kts etc.

Your aircraft performance is based just flying in air at a your relative speed within this air. So it's better to face this moving air and jump up into it when rolling along the ground. Otherwise you would need to match this air speed on the ground (30 kts etc), then add your standard aircraft performance to that.

The Falcon,

Just separate earth from air.

The only time you need to relate to each other is for navigation and landing purposes only...

Your aircraft performance is based just flying in air at a relative speed..

I understand, it's like you say i know. What I was trying to say is that it is not correct to say that the constant wind affects 0 on the FM as bkthunder said. If you read the last post you will notice that i wrote that the wind does not change the aerodynamic performance, or at what relative speed an airplane generates a total of lift etc ... those are static, what changes is the flight as a whole because we cannot escape the earth, we must always head towards a point. If we sail in the wind then we move with it but the vector of gravity does not, (moreover the planes always follow a route, like when they land) So the constant wind affects the flight for these reasons, not on the aerodynamic properties.

This video expresses my concept

Sorry Falcon, but no.

I understand your logic but it’s not correct and doesn’t apply to the specific aviation terminology we are using.

The aircraft height at the end of the runway has nothing to do with its climb performance being effected by the wind. It just means that it reached the end of the runway sooner or later because of the wind direction.

Nobody here has been trying to argue that wind doesn’t effect an aircrafts ground speed and ground track. We have ALL been saying that from the beginning. If that’s what you’re trying to get across then we agree. But steady state wind does not effect the performance (airspeed, climb rate, stall speed etc etc) of an aircraft. These are fundamental inarguable facts of aviation.

It is difficult to explain precisely because of the terminology between what is raltively absolute and what is absolute.

I am simply pointing not to say that the bug found by bkthunder is wrong but that his claim that the constant wind affects 0 on the FM is incorrect.

It is not corrected from a material point but it is corrected from a relative point.

As I wrote in my last post, the wind does not change the aerodynamic performance which remains absolute both with the relative speed and with the speed respect to the ground. As you say once in the air both aircraft have the same absolute climb rate or stall speed (but not the absolute airspeed) but what I say and that they do not have the same absolute climb due to the constant wind. Let me explain. One will rise before the other. Even removing the ground, if we put the two planes side by side, we will see the one with the tailwind exceed the one with the headwind, this is what I mean when I say that the constant wind changes the flight. Constant wind dont change only the aerodynamic point.

Then there is another thing to say. It is practically impossible not to be influenced by the constant wind in flight because we always have a route to follow, so unless we are completely parallel to the wind we will have to face it as if it were a landing.

With constant wind, your relative speed is the same, relative to the aerodynamic point, not to the material point as with the tailwind you arrive first at your destination, therefore also a lower fuel consumption compared to a headwind.

However this video clarifies my thinking.

I sense a problem with the term "flight model" here...

As flight model, we understand the simulation of the various parameters and forces that act on the specific air frame.

It is not directly about how the aircraft interacts with the ground. That is, of course, also modelled and simulated, but is more or less considered as a given and probably simulated/calculated by the DCS base game simulation engine.

Well dont forget the fact that we are not talking about the physical world but about a computer program.

So for that reason things like interaction with the ground in terms of drift and so on has to be accountet there except DCS simulates the forces much more closer to reality. Which is something only Devs can really tell.

As I wrote in my last post, the wind does not change the aerodynamic performance which remains absolute both with the relative speed and with the speed respect to the ground. As you say once in the air both aircraft have the same absolute climb rate or stall speed (but not the absolute airspeed) but what I say and that they do not have the same absolute climb due to the constant wind. Let me explain. One will rise before the other. Even removing the ground, if we put the two planes side by side, we will see the one with the tailwind exceed the one with the headwind.

We are talking in circles. What is absolute airspeed? Do you mean ground speed? Airspeed only refers to the aircrafts speed through the air, which doesn’t include any of the airs movement (wind).

Yes a headwind takeoff will be shorter then a tailwind takeoff.

But the climb rate of the two aircraft will be the same. They will not travel the same distance over the ground. But they will achieve the same altitude at the same time.

Nobody here is arguing that wind should not effect the ground speed and the ground track of the aircraft. Those are obvious effects.

@Deano87 I don't know why you are still arguing with 'the falcon'.

If someone like he does posts things like

...if you don't understand the most basic things...

...Just to be clear for those who are slow to understand...

...Imop you all, are misunderstanding things written...

any further discussion is obviously completely useless and just a waste of time.

At this point I'm not so much arguing as just trying to understand his perspective. English isn't his first language so using confusing terms like "Absolute airspeed" when he means ground speed can make it very easy to get wires crossed. I think he has also confused our point of the FM not being effected by wind to mean that the aircraft should ignore wind all together which is obviously not what we are saying.

At least the bug should be fixed in an upcoming beta. :)

At this point I'm not so much arguing as just trying to understand his perspective...I think he has also confused our point of the FM not being effected by wind to mean that the aircraft should ignore wind all together which is obviously not what we are saying.

Thx to try to understand, english is not my native language and i actually check with the translator before posting something but the translator is not perfect.

For FM i mean the whole system, the aerodynamic and the "physical" one, or as cofcorpse called it material point, and as he said the correct interaction between the two make a correct FM. But bkthunder said that state wind has 0 effect on the FM, and Delareon was also perplexed like me if you read his first post, and if you read my first post you will clearly see that I was trying to correct what bkthunder said.

So I mean that FM is not only composed of aerodynamic forces but also of the laws of mass/inertia gravity/energy.

What is absolute airspeed? Do you mean ground speed? Airspeed only refers to the aircrafts speed through the air, which doesn’t include any of the airs movement (wind).

Thx for that question.Yes I should have been more careful about terms. Exactly, the airpeed is not referred to the ground, in fact i have never said this, it refers only to the speed of the air flowing on the aircraft. So the airspeed is mainly part of the FM since without it there is no resistance or lift, however there are other forces, which is why i referred to ground speed as absolute airspeed, but not as if it were just a ground that moves under your feet, but as physical forces.

For example. When you are at 30k feet and have a CAS aerodynamic speed of 250kts. The CAS speed facilitates the pilot to understand how much air resistance the aircraft will be able to exercise, therefore to maneuver, this because of the low density of the air, therefore it is related to aerodynamics and mainly influences the FM. But there is another absolute thing that affects FM and it's the energy possessed by the aircraft, which is not related to aerodynamics but to the true speed, the energy.

Think about what would happen if you put two aircraft at 30k but one with a 400kts cas and the other with a 400kts ground speed, and you send them vertically the one who has more energy goes up more.

A similar thing happens for the constant wind, there are masses and energies at stake. The moment the pilot decides to oppose the constant wind direction as during the landing where he follows a point, he will have to face it.This also applies to higher altitudes to navigate. It's like in the video of the bullet that i posted. The side constant wind will couses a resistance on the tail and on the whole surface where it impacts, so i would say that it affects the FM.

If I'm wrong about this, someone prove me the opposite.

@Deano87 I don't know why you are still arguing with 'the falcon'.

If someone like he does posts things like

...if you don't understand the most basic things...

...Just to be clear for those who are slow to understand...

...Imop you all, are misunderstanding things written...

any further discussion is obviously completely useless and just a waste of time.

You are instrumentalizing what my words are. I didn't start giving troll or pathetic to someone. At least read what i wrote above.

The side constant wind will couses a resistance on the tail and on the whole surface where it impacts, so i would say that it affects the FM.

If I'm wrong about this, someone prove me the opposite.

If this would be the case, every aircraft would weathervane into the wind during flight and you would have to correct with the rudder which clearly isn't the case. That's the proof.

If this would be the case, every aircraft would weathervane into the wind during flight and you would have to correct with the rudder which clearly isn't the case. That's the proof.

Now tell me, why during the whole landing procedure the pilot uses the rudder to face the constant wind while at altitude he doesn't (according to what you say). I want an explanation of the physical phenomenon because nobody has given me.

Now tell me, why during the whole landing procedure the pilot uses the rudder to face the constant wind while at altitude he doesn't (according to what you say). I want an explanation of the physical phenomenon because nobody has given me.

He doesn't use the rudder during the approach!

He simply applies the WCA (wind correction angle) and flies a corrected heading so his track in relationship to the ground leads him to the runway.

Again. Once ground (the runway) comes into play, we are talking about navigation and hence ground speed and ground track .

None of these items has anything to do with aerodynamics or performance which is related to air speed, not ground speed.

E.g. runway heading 090°, wind direction 360° = WCA -10deg. With the WCA applied you need to fly a heading of 080° to maintain a track of 090deg.

The aircraft flies a heading of 080° without the need of any rudder application. The same is valid for all other directions.

If the pilot wants to navigate at 30000ft towards a fixed point like e.g. a VOR and there's a crosswind component which requires a 10deg WCA, he flies the corrected heading to maintain the desired track to the VOR.

Without the fixed point on earth you don't notice any difference if you fly a heading of 080°, 090° or any other heading, regardless of the wind speed and direction.

Think harder about my question, "What is wind?"

From the aircraft's perspective, there is no such thing. From the aircraft's perspective, the only thing that is "felt" is wind "gusts." This is because a gust or burst of wind does not last long enough for inertia to be overcome.

Let me try this example: Imagine you are drilling through the earth and suddenly the earth's direction of rotation changes. You would feel the change up until your inertia catches up with the new direction, and then it would be like nothing happened.

The earth's rotation is a constant "wind", yet you would continue drilling in the same direction relative to the earth.

Here's another one: Imagine a floating island with a car on top. The island floats towards the East, and the car drives towards the North. To the driver, he is driving North, but actually he is driving North-East.

The side constant wind will couses a resistance on the tail and on the whole surface where it impacts, so i would say that it affects the FM.

If I'm wrong about this, someone prove me the opposite.

Like I said before Falcon.

When you write about this, (separate the two)

The plane will only feel the force of "wind" when the (wheels are on the ground)

When an aircraft is in the air, it's in that "bubble of air" It's all relative to "that aircraft" and proformance.

When you try and come out of this bubble (that's moving around) COMPARED to the (ground) only.

You then need to fly through this (MOVING air bubble) on an angle that can lineup with the runway (That's relative to the ground). There is still no EXTRA force on the rudder, only the force is what YOU put on it against the forward movement of flight in this moving air so YOU can align with the runway that's on the ground that's in a "fixed position" on the ground.

Usually that would be a de crab, YOU force the aircraft to yaw left in the pic above. (Before this, you are just flying around in a landing configuration) You are only steering to allow for the moving (AIR MASS) you are flying in compared to a fixed point on the ground.

EDIT

When you build an FM for aircraft. ED does not worry about the wind at all here. (There is no wind)

Why? As far as ED is concerned it's all just still and the aircraft fly's (powered) around in the sky and the performance figures should match up.

What is a problem if the (movement) of ED's simulated (air mass) over the ground is out. (With you in it)

When you think / write about his stuff, keep it all separated.

Relative to itself while flying around. (No strings attached)

Relative to the ground (Takeoff, Navigation, landing)

Hi!

Now tell me, why during the whole landing procedure the pilot uses the rudder to face the constant wind while at altitude he doesn't (according to what you say). I want an explanation of the physical phenomenon because nobody has given me.

Rudder is not used during the whole landing but only at flare to de-crab.

There is another method which is call slideslip and require rudder action to keep the nose external to the trajectory (slip). But rudder action is no way intended to counteract the wind. Just to point the nose outboard of the velocity vector.

https://en.wikipedia.org/wiki/Crosswind_landing

The choice of those methods depends mainly on a/c flown.

On F-16, no slieslip ... and no de-crabing is recommended due to possible side effect of FLCS.

Your problem is that you are considering the ground as reference. But this is wrong because once a/c is flying, the reference is no longer the ground.

In flight, ground is moving relative to your a/c.

On ground, the air mass is moving relative to your a/c.

The delicate point is the transition between the both. But in flight, one a/c is fully in air mass reference, wind has NO effect on it.

Just as earth's rotation has no effect on you when you are standing in its surface. Your body are part of the overall inertial of the earth displacement relative to space.

Gusts / wind burst can be considered similar to bumps on the roads when you are driving through a field.

bbrz and bkthunder are fully correct.

Regards.

Rudder is not used during the whole landing but only at flare to de-crab.

What's de-crab? ;)