Some kind of autopilot?

[DieHard]

I made a generic mission for the hog and it works fine.

 

I tried the Vegas landing and it works fine.

 

Then went back to the Vegas take off and the same thing, ailerons deflect full right roll.

 

A genuine Thank You to those of You who actually tried to help.

 

Never have been a fan of the pre-canned missions DCS offers with the new aircraft.

 

Never have had a negative issue flying in MP, 104th Phoenix server in now the 1.5, especially flying the Warthog or the Black Shark.

[kylekatarn720]

Yep, the only thing affected by the wind is the groundspeed as can clearly be seen before and after your 180 turn.

 

On the contrary, wind does effect airspeed. In the video i tried maintaining 283 knots IAS. on a tail wind that 283 ias was equal to 317 tas and 288 gs but while i was flying in to the wind, that same 283 ias was equal to 317 tas and 346 gs. What that means is, in that same situation if i tried to maintain, lets say 300 gs (instead of an IAS value), the ias i get would be lower while i was flying on a tail wind. Only difference being the wind direction, it does effect airspeed.

[BigDuke6ixx]

On the contrary, wind does effect airspeed. In the video i tried maintaining 283 knots IAS. on a tail wind that 283 ias was equal to 317 tas and 288 gs but while i was flying in to the wind, that same 283 ias was equal to 317 tas and 346 gs. What that means is, in that same situation if i tried to maintain, lets say 300 gs (instead of an IAS value), the ias i get would be lower while i was flying on a tail wind. Only difference being the wind direction, it does effect airspeed.

 

That's you changing the throttle to maintain the same GS (navigation issue) and not the wind having an aerodynamic affect on airspeed. You held about 280 all through your turn and the only thing that changed was the groundspeed.

 

What exactly were you trying to prove?

[kylekatarn720]

In that video im flying on a 90-270 course, in the first part my heading is 270 (which is in to wind) , in the second part my heading is 90 ( which is tailwind). In this situation while my ias and tas stays the same, my ground speed is significantly higher while flying in to the wind. My ias and tas being the same i cover more ground in a headwind,please explain to me why is that?

Edited June 26, 2017 by kylekatarn720

[BigDuke6ixx]

In that video im flying on a 90-270 course, in the first part my heading is 270 (which is in to wind) , in the second part my heading is 90 ( which is tailwind). In this situation while my ias and tas stays the same, my ground speed is significantly higher while flying in to the wind. My ias and tas being the same i cover more ground in a headwind,please explain to me why is that?

 

 

You start off at 090 with the tailwind (GS 436) and end up at 270 into wind (GS 288 ) , so everything is as it should be. Clearly you need to have a good hard think about all this.

 

Anyway, I'm looking forward to your weathervane video.

Edited June 26, 2017 by BigDuke6ixx

[Buzzles]

Last few pages are guff in relation to FatSlapper's OP, fyi.

[kylekatarn720]

You start off at 090 with the tailwind (GS 436) and end up at 270 into wind (GS 288), so everything is as it should be. Clearly you need to have a good hard think about all this.

 

Anyway, I'm looking forward to your weathervane video.

 

having my dinner right now, ill probably post the video in a couple of hours.

 

To change any objects velocity, you need to give it acceleration. For acceleration, you need to apply force.

 

The force applied on an aircraft by a wind from any direction, will manipulate the aircrafts acceleration, so it will change its speed.

 

Edit: @Buzzles well you are right what can i say.

[BigDuke6ixx]

having my dinner right now, ill probably post the video in a couple of hours.

 

To change any objects velocity, you need to give it acceleration. For acceleration, you need to apply force.

 

The force applied on an aircraft by a wind from any direction, will manipulate the aircrafts acceleration, so it will change its speed.

 

Except that you've just posted a video that shows only GS is affected by the wind. Look at the video again, into wind or with a tailwind, you had the same airspeed. What is it you don't understand about your own results?

[shagrat]

No, completely wrong. The crosswind isn't pushing harder on the tail and trying to rotate the plane. Go and try it in the A-10 for yourself. Properly trimmed and flying hands off, you won't see a tendency for the plane to weathervane into the wind.

You are aware that "properly trimmed" actually means you adjust the controls to counteract the forces at work?!

 

You can just activate the "ALT/HDG autopilot" it trims the A-10C for you and even adjusts for changes in windspeed...

 

What I don't understand is, you had real life motor plane pilots, glider pilots and aircraft engineers telling you the same...

 

If you have a pilot license you actually should know that a crosswind is affecting the tail (BIG rudder!) as the effect / force we talk about is an integral part of the rudders ability to control yaw on most planes... I know a monofoil plane uses asymmetric airbraking.

 

If you have the chance, try and fly a glider. Get light on the controls and see what the crosswind does if you don't apply rudder and aileron to compensate, then come back here and tell us again about the "completely wrong".

Edited June 26, 2017 by shagrat

[kylekatarn720]

it does effect it, since i need different power settings to keep that ias same on both ways.

[shagrat]

it does effect it, since i need different power settings to keep that ias same on both ways.

Actually you are somewhat both right, but Mr. I-am-a-pilot doesn't bother to explain the different "speeds" to you...

 

In a plane you have at least two relevant speeds (there are more, but for the sake of simplicity concentrate on Ground Speed and Indicated Air Speed).

GS is the speed your plane travels from point A to point B over ground, whereas IAS is the speed of the wind relative to your plane (could say how fast the air around you is flowing over the airfoils).

 

What you usually see in cockpit instruments is IAS. When you fly into a headwind of course it slows you down relative to the ground, while the airflow over your wings remains the same or maybe rises. With a tailwind GS increases, as you travel with the wind now, but your IAS will remain the same or decreases.

 

But that is distracting from the original posters question what causes the strange "autopilot" like movement of the plane without him making control inputs, which is a combination of weight/drag from asymmetric load and crosswind weather vaning/cocking the nose a bit into the wind.

[WindyTX]

Once the Aircraft is Airborne the Wind doesnt apply any force unless there is a shear layer or turbulence as the Aircraft is already miving within the Air. The only forces are Thrust Drag and Lift and weight plus the adjustments you make with the controls. Wind per se has no effect what at all on the Aircraft aerodynamically.

You are just moving with you speed in the air plus the speed of the Air. An Airliner in a 150 knot jetstream has zero affect vs an Airliner in still air handling wise. Forces only change when the wind velocity itself changes.

 

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[shagrat]

Once the Aircraft is Airborne the Wind doesnt apply any force unless there is a shear layer or turbulence as the Aircraft is already miving within the Air. The only forces are Thrust Drag and Lift and weight plus the adjustments you make with the controls. Wind per se has no effect what at all on the Aircraft aerodynamically.

You are just moving with you speed in the air plus the speed of the Air. An Airliner in a 150 knot jetstream has zero affect vs an Airliner in still air handling wise. Forces only change when the wind velocity itself changes.

 

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After you trimmed the plane, yes.

[shagrat]

@WindyTX - if you fly a landing approach on 21, you have a 20kts crosswind from 340° and the plane is aligned with the runway. Now as the nose of the plane is turned towards the runway what will happen if you neutralize the ailerons and rudder? Will the plane simply be blown beside the runway, by the crosswind, or does it start turning its nose into the direction of the wind... And no we do not trim the plane to hold a crab angle or slip to compensate.

[kylekatarn720]

Actually you are somewhat both right, but Mr. I-am-a-pilot doesn't bother to explain the different "speeds" to you...

 

In a plane you have at least two relevant speeds (there are more, but for the sake of simplicity concentrate on Ground Speed and Indicated Air Speed).

GS is the speed your plane travels from point A to point B over ground, whereas IAS is the speed of the wind relative to your plane (could say how fast the air around you is flowing over the airfoils).

 

What you usually see in cockpit instruments is IAS. When you fly into a headwind of course it slows you down relative to the ground, while the airflow over your wings remains the same or maybe rises. With a tailwind GS increases, as you travel with the wind now, but your IAS will remain the same or decreases.

 

But that is distracting from the original posters question what causes the strange "autopilot" like movement of the plane without him making control inputs, which is a combination of weight/drag from asymmetric load and crosswind weather vaning/cocking the nose a bit into the wind.

 

It's alright i know what they are, i mean ias, tas and gs.

 

Once the Aircraft is Airborne the Wind doesnt apply any force unless there is a shear layer or turbulence as the Aircraft is already miving within the Air.

 

Hmm, how does a crosswind pushes you to the side then if wind doesnt apply any force?

[dillio]

I'm gonna wade in here: The plane weathervanes into the wind. Always, at all times, during flight. THAT IS LITERALLY WHAT THE VERTICAL STAB IS THERE FOR. Why else did you think your course was different from your heading?

Edited June 27, 2017 by dillio
What I meant to say.

[WindyTX]

No when you fly the approach most people fly balanced with the nose crabbed into wind. There are 2 crosswind landing techniques. One favored by military pilots is to kick the nose straight in the flare and the aircraft lands straight when you kick it straight you have to use into wind aileron to keep the wings level. The second technique is to push the nose straight as you start to flare and lower the into wind wing to land with the upwind wheels first. I used the first method in the military and the second method on the B777 as it is much slower to respond

[WindyTX]

I guess this conversation has rather left the original point. One of the problems with DCS is that when you put a wind in they double it by about 2000ft which is rather unrealistic so that you have to adjust your drift angle all the time on final when you have a crosswind.

I apologize if my earlier responses didnt help earlier but I was just trying to help. If you have an L39 I will happily demonstrate the effects just message me.

 

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[Yurgon]

Yep, correct. In the air the effect is called "directional stability", it does the same as weathervaning on the ground, just not so pronounced.

 

Is what you describe simulated in DCS?

 

Edit: Disregard, I tested it, see below.

Edited June 27, 2017 by Yurgon

[Weta43]

It's the same as the old swimmer crossing a river problem they used to give you at high school.

 

If the swimmer swims slowly across a river with a fast current, he has to point more upriver than if he swims fast across a river with slow current but in both cases the swimmer swims straight into the apparent flow, not crabwise.

 

If you're flying no rudder, wings level, and the ball is centred, you're not 'weathervane-ing'

If the ball isn't centred, you're not flying correctly (unless you're about to land or are taking off).

[Yurgon]

Note that the Animation does not show, the pilot using rudder or aileron to keep the nose on course, pointing straight, if he would let the rudder/aileron go, the tail would catch the wind and yaw the plane around the center of gravity resulting in the plane flying a curve into the wind.

 

Coming back to my earlier question if this weathervaning-effect of airborne aircraft exists in DCS, I tried it out. :smartass:

 

For starters, I set the wind to come from 360 at 20 kts. That should be plenty wind to prove the theory. I took off from Nellis, with the obvious weathervaning tendency that I believe is completely undisputed. Once airborne, I flew straight north (into the wind) until established at 10,000 ft. I then flew a 90 degree right hand turn and headed east for a while. Without ever trimming, I had to keep the stick pushed forward (dang it, holding that Warthog for 20 minutes at a time is a pain I'm here to tell ya ;)), but other than that, I couldn't find any weathervaning tendency at all. Next I flew a 180 and headed west - again, no weathervaining tendency noticeable. Like, none at all.

 

Clearly, there wasn't enough wind! :smartass:

 

I then repeated the test with a wind of 60 kts. Again, I couldn't discern even the slightest bit of a weathervaning tendency. At a perfectly perpendicular 60 kts crosswind, I guess this effect should have somehow manifested itself.

 

So, either DCS fails to model a fundamental aerodynamic effect, or an aircraft once airborne will not weathervane into the wind (assuming steady winds, of course).

 

For fun and profit, I saved a track (1.75 MB, DCS 2.1, Nevada Terrain, circa 15 minutes). :)

 

Of course I'd love to test this in a real aircraft, but lacking all the required certificates, and the training, and the aircraft, I guess the LBA (German FAA) wouldn't be too happy about it. :D

Edited June 27, 2017 by Yurgon

[kylekatarn720]

Coming back to my earlier question if this weathervaning-effect of airborne aircraft exists in DCS, I tried it out. :smartass:

 

For starters, I set the wind to come from 360 at 20 kts. That should be plenty wind to prove the theory. I took off from Nellis, with the obvious weathervaning tendency that I believe is completely undisputed. Once airborne, I flew straight north (into the wind) until established at 10,000 ft. I then flew a 90 degree right hand turn and headed east for a while. Without ever trimming, I had to keep the stick pushed forward (dang it, holding that Warthog for 20 minutes at a time is a pain I'm here to tell ya ;)), but other than that, I couldn't find any weathervaning tendency at all. Next I flew a 180 and headed west - again, no weathervaining tendency noticeable. Like, none at all.

 

Clearly, there wasn't enough wind! :smartass:

 

I then repeated the test with a wind of 60 kts. Again, I couldn't discern even the slightest bit of a weathervaning tendency. At a perfectly perpendicular 60 kts crosswind, I guess this effect should have somehow manifested itself.

 

So, either DCS fails to model a fundamental aerodynamic effect, or an aircraft once airborne will not weathervane into the wind (assuming steady winds, of course).

 

For fun and profit, I saved a track (1.75 MB, DCS 2.1, Nevada Terrain, circa 15 minutes). :)

 

Of course I'd love to test this in a real aircraft, but lacking all the required certificates, and the training, and the aircraft, I guess the LBA (German FAA) wouldn't be too happy about it. :D

 

Nice testing, i dont need to record and upload a video now i suppose:d

 

Still i gotta say i dont understand why, from what i imagine it really should. Maybe im overlooking something while thinking about the situation.

 

I would love to say it wont hurt to try in a real a/c but probably in this particular situation it will:d

[WindyTX]

Dcs is actually pretty good at modelling most stuff. While there are a few things that are way off and I really think they need to stop trying to simulate stuff that is secret still as far as flying goes, especially with a jetseat and the Rift its pretty realistic so your findings that wind make no difference to the Aircraft once its inflight, apart form the drift aspect, are spot on. There isnt any weathervaning once airborne. Most servers in DCS run zero wind so its not much of a factor. Tomorrow I will file a bug report for the amount of shear added automatically to the sim.

 

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Edited June 27, 2017 by WindyTX

[AlphaOneSix]

I have not yet read all of the responses here, but have any pilots chimed in? I have just couple hundred hours so I'm no expert, but I don't remember any aircraft I've ever flown weathervaning in flight. Sure, if there is a crosswind, the aircraft will drift with the crosswind as seen on a ground track, but the aircraft doesn't try to weathervane into the wind. It only weathervanes when the aircraft can't move in the direction the wind is pushing it (i.e. on the ground).

[WindyTX]

I have 10,000 hours which is why I was trying to help but obviously did a shit job at helping.

 

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