OnlyforDCS Posted October 30, 2015 Posted October 30, 2015 (edited) Sorry to drag this out again but something is bothering me about all this... MBot wrote in a previous post "No, because the whole aircraft is moving with the wind (just as the balloon is), therfore between aicraft and air, no crosswind exists.". It doesn't do that in the sim because the airpseed indicator would have to read '0' if it moved along with the wind. Also, it would crash because no lift is created. Something is amiss with the FM but it's not what you guys are suggesting... Im afraid that you're not getting this. Let me try and explain as simply as I can over the internet. The aircraft is moving in relation to the entire airmass (What you would measure in the aircraft as IAS). The airmass is moving in relation to the ground (What someone on the ground would notice as Wind). The aircraft's movement in relation to the ground would be the combined sum of two vectors of the aircraft in relation to the airmass (V1) + the airmass in relation to the ground (V2). V1 + V2 = V3. Okay, maybe it's not that simple so let me try with another example which should be familiar to those who have studied relativity a bit. :) Imagine that you are riding in a train. The train is moving at a certain fixed speed in relation to the ground. However you in the train are going to the restaurant car to get a snack at a nice fast pace because you are hungry, also because you are hungry you are not looking outside and not really aware of the speed of the train. You are in relation to the train moving at 5 km/h, completely unaware that the train is speeding at 120 km/h in relation to the ground. Now simply imagine that you are the plane, the train is the airmass, and the ground is the ground. Edited October 30, 2015 by OnlyforDCS Current specs: Windows 10 Home 64bit, i5-9600K @ 3.7 Ghz, 32GB DDR4 RAM, 1TB Samsung EVO 860 M.2 SSD, GAINWARD RTX2060 6GB, Oculus Rift S, MS FFB2 Sidewinder + Warthog Throttle Quadrant, Saitek Pro rudder pedals.
chaos Posted October 30, 2015 Posted October 30, 2015 Im afraid that you're not getting this. . I guess so... However, you're not answering my question. I understand windvectors and the effect on coarse and speed. This is not rocket science. If the aircraft is just moving along with the wind, it's airspeed would read '0'. it would stall, obviously. It is actually flying at around 150 if memory serves (cant check it right now). Read MBot's quote again. What he states is simply not true with regards to the Migs mission file. Forget about the balloon... Again, i agree there's something wonky about the Mig's behaviour when wind is introduced but I can't figure it out. "It's not the years, honey. It's the mileage..."
OnlyforDCS Posted October 30, 2015 Posted October 30, 2015 (edited) I guess so... However, you're not answering my question. I understand windvectors and the effect on coarse and speed. This is not rocket science. If the aircraft is just moving along with the wind, it's airspeed would read '0'. it would stall, obviously. It is actually flying at around 150 if memory serves (cant check it right now). Erm, let me try to explain some more. The IAS (Indicated AIr Speed) is the speed between the aircraft and the entire airmass. This is what provides the lift of the aircraft. If the entire airmass is moving (Wind) in relation to the ground, then the aircraft is ALSO moving in relation to the ground in that direction. So the actual WIND the aircraft experiences is 0/kph. (Just think of the air around the aircraft as the train in my previous example and it will be clear) Is that any clearer? I don't think I can make it any clearer. This is very basic physics really. The problem with the Mig21 is that it is weather-vaning in the wind when it clearly isn't supposed to be doing that. Edited October 30, 2015 by OnlyforDCS Current specs: Windows 10 Home 64bit, i5-9600K @ 3.7 Ghz, 32GB DDR4 RAM, 1TB Samsung EVO 860 M.2 SSD, GAINWARD RTX2060 6GB, Oculus Rift S, MS FFB2 Sidewinder + Warthog Throttle Quadrant, Saitek Pro rudder pedals.
chaos Posted October 30, 2015 Posted October 30, 2015 (edited) This is very basic physics really. I appreciate you're taking the time to explain but I don't get your logic. Wind is additive to the aircraft's speed. If I fly along with a nice and steady tailwind and, all of a sudden, the wind shifts 180deg i will see the effect on my IAS (i.e. it will increase). Forget about balloons and the ground... Just the effect wind has on an airframe. Now, read your comments again. Doesn't make sense, does it? Edited October 30, 2015 by chaos "It's not the years, honey. It's the mileage..."
OnlyforDCS Posted October 30, 2015 Posted October 30, 2015 (edited) I appreciate you're taking the time to explain but I don't get your logic. Wind is additive to the aircraft's speed. If I fly along with a nice and stready tailwind and, all of a sudden, the wind shifts 180deg i will see the effect on my IAS (it will increase). Forget about balloons and the ground... Just the effect wind has on an airframe. Now, read your comments again. Doesn't make sense, does it? It makes perfect sense. That is different. You will see a difference because it will cause an acceleration (or decceleration in that case) but once the wind becomes steady again, your IAS will return to the previous value. (However your TAS will be different) Or if we use my analogy again: If the train brakes suddenly, and reverses direction, you will most certainly feel it. But once it gets to a constant speed in the other direction, as far as you are concerned it will feel exactly the same again. For example if you were asleep on the train (moving at 0/kph in relation to your chair or bed on the train) the acceleration would wake you up, might even throw you out of your seat. But if the train is moving at a steady speed, it will feel exactly as if it were stationary. Edited October 30, 2015 by OnlyforDCS Current specs: Windows 10 Home 64bit, i5-9600K @ 3.7 Ghz, 32GB DDR4 RAM, 1TB Samsung EVO 860 M.2 SSD, GAINWARD RTX2060 6GB, Oculus Rift S, MS FFB2 Sidewinder + Warthog Throttle Quadrant, Saitek Pro rudder pedals.
Cobra847 Posted October 30, 2015 Posted October 30, 2015 Fixed internally. Nicholas Dackard Founder & Lead Artist Heatblur Simulations https://www.facebook.com/heatblur/
RogueRunner Posted October 30, 2015 Posted October 30, 2015 I appreciate you're taking the time to explain but I don't get your logic. Wind is additive to the aircraft's speed. If I fly along with a nice and stready tailwind and, all of a sudden, the wind shifts 180deg i will see the effect on my IAS (it will increase). Forget about balloons and the ground... Just the effect wind has on an airframe. Now, read your comments again. Doesn't make sense, does it? No you won't, indicated airspeed stays the same, groundspeed however, will increase. Another example, if you fly along at 50mph in a piper cub, no wind. Your airpseed indicator will read 50mph and your groundspeed will be 50mph. Now if you have a headwind of 50mph, your airpseed indicator still indicates 50mph, your groundspeed will be zero, ie hangin still to someoone standing on the ground but you will not stall, it will happily just hang there in the air to an observer on the ground. With the price of ammunition these days do not expect a warning shot.
OnlyforDCS Posted October 30, 2015 Posted October 30, 2015 (edited) Fixed internally. Thanks for the heads-up. Edited October 30, 2015 by OnlyforDCS Current specs: Windows 10 Home 64bit, i5-9600K @ 3.7 Ghz, 32GB DDR4 RAM, 1TB Samsung EVO 860 M.2 SSD, GAINWARD RTX2060 6GB, Oculus Rift S, MS FFB2 Sidewinder + Warthog Throttle Quadrant, Saitek Pro rudder pedals.
OnlyforDCS Posted October 30, 2015 Posted October 30, 2015 Another example, if you fly along at 50mph in a piper cub, no wind. Your airpseed indicator will read 50mph and your groundspeed will be 50mph. Now if you have a headwind of 50mph, your airpseed indicator still indicates 50mph, your groundspeed will be zero, ie hangin still to someoone standing on the ground but you will not stall, it will happily just hang there in the air to an observer on the ground. Yes this is another good example. Much better than my stupid train :thumbup: Current specs: Windows 10 Home 64bit, i5-9600K @ 3.7 Ghz, 32GB DDR4 RAM, 1TB Samsung EVO 860 M.2 SSD, GAINWARD RTX2060 6GB, Oculus Rift S, MS FFB2 Sidewinder + Warthog Throttle Quadrant, Saitek Pro rudder pedals.
Hummingbird Posted October 30, 2015 Posted October 30, 2015 No you won't, indicated airspeed stays the same, groundspeed however, will increase. Another example, if you fly along at 50mph in a piper cub, no wind. Your airpseed indicator will read 50mph and your groundspeed will be 50mph. Now if you have a headwind of 50mph, your airpseed indicator still indicates 50mph, your groundspeed will be zero, ie hangin still to someoone standing on the ground but you will not stall, it will happily just hang there in the air to an observer on the ground. Hence how seagulls seemingly are able to hover on windy days :)
chaos Posted October 30, 2015 Posted October 30, 2015 No you won't, indicated airspeed stays the same, groundspeed however, will increase. Nope, you're wrong... ground but you will not stall, it will happily just hang there in the air to an observer on the ground. Forget about groundspeed... this is not important. Yes, it will hang motionless in the air because 50 - 50 = 0 I get it... Never mind. I get the feeling we're talking about 2 different things. What I would like to know is why did the Mig show that behaviour. What was the actual bug that caused this anomaly. Could Cobra comment on that because I find that far more interesting than balloons, trains and seagulls. :D "It's not the years, honey. It's the mileage..."
OnlyforDCS Posted October 30, 2015 Posted October 30, 2015 Actually he is right, and you are wrong but you are almost there. (Hint: 50 (IAS) - 50 (Windspeed) = 0 (Groundspeed)) We did try, though. As for the bug, the important part is that it's fixed. Current specs: Windows 10 Home 64bit, i5-9600K @ 3.7 Ghz, 32GB DDR4 RAM, 1TB Samsung EVO 860 M.2 SSD, GAINWARD RTX2060 6GB, Oculus Rift S, MS FFB2 Sidewinder + Warthog Throttle Quadrant, Saitek Pro rudder pedals.
chaos Posted October 30, 2015 Posted October 30, 2015 Actually he is right, and you are wrong but you are almost there. (Hint: 50 (IAS) - 50 (Windspeed) = 0 (Groundspeed)) We did try, though. As for the bug, the important part is that it's fixed. Isn't that exactly what I wrote before you did...? I do this stuff for a living. I'd hope that I would have at least working knowledge on how wind affects aircraft after almost 30 years in the business... but... I never assume I know it all. Again, I think we're not talking about the same thing. Best to drop it. As for the actual bug... I would like to know so, please, do not decide things for me. Cobra can choose to answer if he so pleases. "It's not the years, honey. It's the mileage..."
OnlyforDCS Posted October 30, 2015 Posted October 30, 2015 Sorry, I didn't mean to be patronizing was just trying to help. Consider the matter dropped. Current specs: Windows 10 Home 64bit, i5-9600K @ 3.7 Ghz, 32GB DDR4 RAM, 1TB Samsung EVO 860 M.2 SSD, GAINWARD RTX2060 6GB, Oculus Rift S, MS FFB2 Sidewinder + Warthog Throttle Quadrant, Saitek Pro rudder pedals.
chaos Posted October 30, 2015 Posted October 30, 2015 Sorry, I didn't mean to be patronizing was just trying to help. Consider the matter dropped. No worries. I appreciate you're trying to help. The difficulties of communicating with snippets of text and all that. No harm done. "It's not the years, honey. It's the mileage..."
iFoxRomeo Posted October 30, 2015 Posted October 30, 2015 You guys are funny. You didn´t even read chaos example carefully. ...If I fly along with a nice and steady tailwind and, all of a sudden, the wind shifts 180deg i will see the effect on my IAS (i.e. it will increase)... He is absolutely right. Did you hear about inertia? At first IAS would increase and then drop to the speed corresponding to the powersetting. Comparing the Mig-21 with a balloon...interesting... Fox Spoiler PC Specs: Ryzen 9 5900X, 3080ti, 64GB RAM, Oculus Quest 3
MBot Posted October 30, 2015 Posted October 30, 2015 He is absolutely right. Did you hear about inertia? At first IAS would increase and then drop to the speed corresponding to the powersetting. Comparing the Mig-21 with a balloon...interesting... It has been mentioned multiple times in this thread that we are talking about steady, uniformly flowing wind. And such wind does not aerodynamically affect aircraft by the same principles as it does not affect balloons. Or to get back to chao's initial question: MBot wrote in a previous post "No, because the whole aircraft is moving with the wind (just as the balloon is), therfore between aicraft and air, no crosswind exists.". It doesn't do that in the sim because the airpseed indicator would have to read '0' if it moved along with the wind. Also, it would crash because no lift is created. Obviously the aircraft still has to move relative to the surrounding airmass to create airflow over the wing, which generates lift in order to fly (I assumed this basic principle should be clear). This still doesn't change the fact that the aircraft is also moving along with a moving airmass and therefore does not experience anything like "crosswind".
AG-51_Razor Posted October 30, 2015 Posted October 30, 2015 Just think of the aircraft in the wind like it was a boat in the water. If it is traversing a stream, or strong current, it just needs to point in a direction that compensates for the direction of the current in order to get to where it's going. The indicated speed of the boat (or plane) is the same, no matter what direction it is headed, the only difference is the speed it makes good over the earth. If it is going downstream (or downwind), you would add the speed of the current to the speed of the boat and if it were going against the current you would subtract it. As the desired direction of the boat changes, it is just a matter of vector math to figure out how fast it is actually covering the distance to destination. The indicated speed doesn't show any affect from the water (or wind). Does that make sense? [sIGPIC][/sIGPIC]
Nerd1000 Posted October 31, 2015 Posted October 31, 2015 (the sideslip the MiG-21 experiences while flying in steady wind is definitely not correct though, and the other planes don't seem to do this. So there is something strange going on with the MiG flight model) If I were a betting man I'd put money on some part of the FM using the aircraft's velocity vector relative to the ground when it should be using the aircraft's velocity vector relative to the air.
billeinstein Posted February 17, 2016 Posted February 17, 2016 It's in a 50 m/s wind...Tacview-20160217-232201-DCS.txt.rar [sIGPIC][/sIGPIC]
CoBlue Posted February 17, 2016 Posted February 17, 2016 (edited) If I were a betting man I'd put money on some part of the FM using the aircraft's velocity vector relative to the ground when it should be using the aircraft's velocity vector relative to the air. I found this some time ago http://forums.eagle.ru/showthread.php?t=133746 don't know if it's been fixed or related to this topic. Edited February 17, 2016 by CoBlue i7 8700k@4.7, 1080ti, DDR4 32GB, 2x SSD , HD 2TB, W10, ASUS 27", TrackIr5, TMWH, X-56, GProR.
billeinstein Posted February 19, 2016 Posted February 19, 2016 I found with the 50 m/s wind in mission editor, the pilot ejecting from a grounded aircraft will have a speed near 110 m/s. [sIGPIC][/sIGPIC]
zaelu Posted February 19, 2016 Posted February 19, 2016 Which way? [sIGPIC][/sIGPIC] I5 4670k, 32GB, GTX 1070, Thrustmaster TFRP, G940 Throttle extremely modded with Bodnar 0836X and Bu0836A, Warthog Joystick with F-18 grip, Oculus Rift S - Almost all is made from gifts from friends, the most expensive parts at least
Bestandskraft Posted February 22, 2016 Posted February 22, 2016 Fixed internally. Although as far as I can tell none of the changelogs mention it, the issue of crosswinds aloft causing the aircraft to roll is no longer present in 1.5.3.50487.
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