Vr: The speed at which the pilot begins to apply control inputs to cause the aircraft nose to pitch up, after which it will leave the ground. My question is: why on airbus computaion EFB(electronic flight bag) there are so big margin of rotation speed in cofiguration flaps one, from 155kts till 175kts(on the same aerodrome and on the same runway) According to formula of equation lift L = (1/2) d v2 s CL Where: L = Lift, which must equal the airplane's weight in pounds d = density of the air. This will change due to altitude. These values can be found in a I.C.A.O. Standard Atmosphere Table. v = velocity of an aircraft expressed in feet per second s = the wing area of an aircraft in square feet CL = Coefficient of lift , which is determined by the type of airfoil and angle of attack.
I've always heard airspeed described as the speed of the plane relative to the air and that doesn't make sense to me, but after watching this I see that it is the speed of the air moving over the wings and that makes sense. I finally understand the difference between air and ground speed.
With Headwind of 10 Knots and Groundspeed of 80 Knots. The Headwind is in way resisting the forward movement of aircraft and giving lift and aircraft will takeoff from a shorter distance as compared to zero windspeed. My strange question is when headwind 10 knots it is 80 + 10 = 90 and not 80 -10 = 70 question 🤔 🙄. Please do reply. I know your explanation is perfectly right but please do clarify.
Brilliant video, at first when I saw you start to write on the virtual whiteboard I thought this video would be difficult to understand, great video, and I like how you use different scenarios to explain the same principle you're teaching us! All the best to you in your career!
If you fly at 80 knt (GS=TAS) with no wind, then suddenly you get 10 knts HDW. Will it reduce your GS by 10 or will in increase the TAS with 10? Also why?
at 7:46 , you find airspeed = ground speed = 80 knot with no wind , thats wrong , it should be both 70 knot because in the second one your groundspeed 80 knot with headwind.There is a contradiction between 2
I have a question! I've seen some graphs recently of altitude and ground speed plotted as they happened. Why would you chose to plot those two together on a graph and what is it telling us when the altitude is relatively constant and the ground speed is fluctuating all over the place? Thank you.
So if a plane's maximum speed is stated as 500 kmph, it basically refers to ground speed? Also, it seems airspeed doesn't refer to how fast the craft is moving, merely the speed at which the air is flowing over the wings?
Greetings, I am a sim pilot and I wanted to know why is it the higher you go your airspeed decreases but your ground speed increases? For example my Longitude is plying at 243 knots at 41,000 feet but it has a ground speed of 458 knots. Is the difference because the speed of sound decreases as you gain altitude?
I came here to learn about air speed, only to find out that there's something called GROUND SPEED haha, thought there was only ONE speed. Quick question. Why do planes fly faster at higher altitudes? Or do I ask if it's windier the higher you go?
Hey, many thanks for watching!! Feel free to watch the rest of the videos in Channel and ask me any question you may have. I wish you a great day Gabriele Pilotclimb
I came here because ppl in other channel arguing about the speed of plane. Now i understand why ppl there said "even she used phone to track plane speed ( with iPhone), the real speed of the plane is still faster. Sorry for my bad English
Hello captain , if i am flying at fl370 at TAS of 300 knots and for example faced a headwind of 280 knots then my gs will be 20 knots so this means that my tas becomes 650 the sum of my airspeed and the speed of the airmass i flown into ?
Hey, many thanks for watching... if you subtract/add the wind component to your TAS you will get the GS. The headwind will slow you down..So, in order to calculate the new TAS you need to take this into consideration. Let me know if you still have any questions
@@omarabdalla5626 I think you understand what is the effect of the Headwind on your TAS. If the headwind increase (due to a gust for example) your TAS will increase and, vice versa if you experience a tailwind your TAS will decrease.
@@PILOTCLIMB thank you captain but what i relly need to know is that why the TAS increased with headwind and decreased with tailwind ? And if i was flying at a flight level with a denisty just say as an example 1 and IAS of 200 and tas of 300 if the denisty changes to be 2 for example does this means that the IAS will change and so the TAS ?
@@PILOTCLIMB Yes I know this was just an example. What Im asking for is an explanation of the physics/math involved because it is counter-intuitive.....we generally think a plane flies "easier" or more efficiently in a tailwind, but your example shows that tailwinds actually decrease airspeed. So it would seem that in your example a pilot would have to increase thrust in a tailwind to maintain a given airspeed to prevent stall. Im sure Im missing something as Im not a pilot, but I would like to know the physics explanation of this.
@@FSUmofo I've just watched this and see your point - I totally get the first example but have a hunch that in the second example the indicated airspeed would actually be 80kts and not 70 because the 10kt tailwind would be added to the airflow - I think 70kts is just the speed the plane would need to do in order to maintain the same 80kts as the GS. In other words if the 10kt tailwind suddenly dropped off to zero then the planes indicated airspeed would drop from 80 to 70. . . Hmmm just a hunch - answers on a postcard :-)
@@FSUmofo because in real life ground speed isn't constant. In real life planes stay between "stall speed"(minimal airspeed before losing lift) and "overspeed"(max airspeed plane can handle). So within that envelope getting tailwind actually increaces groundspeed.
Hey, many thanks for watching!! The tailwind pushes the plane so, the GROUNDSPEED is higher at constant Airspeed... at constant GROUNDSPEED the airspeed is lower with tailwind👍 let me know if you have any more questions..
@@PILOTCLIMB oh I see thank you! And also how do I know how fast I’m actually flying with the wind component? Altimeter shows only the airspeed correct?
The Altimeter only shows you your Altitude, on the Airspeed indicator you read the Indicated Airspeed. The sophisticated Aircrafts have the GROUNDSPEED indicated in the Navigation Display or on the FMC, however if the aircraft doesn't tell you your ground speed you can calculate it from your True Airspeed and your wind component... let me know if you need more details..
You can picture the differences easier when think of a glider, a sailplane, planes I started to learn flying with when I was 13 y/o. These planes don't have any engine to pull them through the air, they only fly because they 'fall' due to gravity, gently though, with huge wings to produce the necessary lift to not really fall out of the sky. In these planes AIRspeed matters more than in any other, or better, the plane's attitude in the air, as you can't just make up for lost airspeed - let's call it airflow for the moment - by just pushing a throttle forward to gain more airspeed, airflow around the wings, if you had lost speed. You could only push the nose down to gain more speed. Which results in a loss of altitude, whioch can lead to dangerous situtation near the ground, as you might can imagine. So, managing the planes energy state is key in soaring. There are set limits, normal and max speeds, but especially of a minimum airflow necessary around the wings and fuselage to make a plane fly. Any plane. And for my Bocian back in the days it was min 60 km/h and normal was 80 km/h. Doesn't sound really fast for a plane, right? :D And here's what could happen: if there's strong enough headwinds planes could appear as if they'd be standing still in the air, because the ground speed, the speed that is really the least important one for a piston engine plane, and especially for a sailplane, was so low, because the incoming wind from in front of the plane could generate enough lift alone in windy conditions, so that the plane was barely moving. Compared to the ground. You didn't make much of a distance in relation to the ground. So that's what matters only, it doesn't make a difference for the necessary lift, if you move the plane through the air to generate the airflow around the wings, or if the wind is moving around your static plane with the same speed. Like they test aerodynamics in windtunnels in Formula 1. The car is standing still and they blow wind against and over it, as if it was going with 300 km/h. Samey. Same they can do with wings for planes, fuselages and so on. So, in order for the glider pilot to not exceed the max speed limits of his fragile sailplane, he cannot go just faster to go faster in relation to the ground, when his airspeed indicator tells him, that he's 'going' with 80 km/h. Unfortunately not going anywhere when the wind came with 80 km/h from in front (which was 22 m/s). That would relate in 0 km/h ground speed. If he pushed the nose down to not have to stand still up there forever, he would then gain more indicated airflow... um speed ... around his wings. Maybe 100 km/h. And this would mean he would go by 20 km/h in relation to the ground. If there's no wind at all he had to move the plane with 80 km/h to create the same airflow around the wings, which would result in 80 km/h in relation to the ground. And vice versa: when headwind slows a plane down in relation to the ground, then tailwind must make it faster. You have to subtract, not add, the tailwind from your speed through the air in order to know if you have reached the necessary airflow/speed around your wings. Tailwind is taking airflow away from your wings. Wrong direction so to speak. A plane doesn't fly with airflow from behind. It works only the other way round. The more wind from behind, the faster you have to go (in relation to the ground!) in order to compensate what tailwind takes away from you. Headwind on the other hand, adds airflow around your wings - correct direction - thus you can go slower (in relation to the ground!) in order to generate the same airspeed around your wings. It's always only about the speed of the air around your wings. This result in different speeds of the planes the have to go through the air not only in windy conditions, but also depending on the altitude, as air gets thinner and thinner the higher you go, hence you have to go faster and faster to get the same amount of air (mass) around your wings per second, to not stall and fall to the ground. This is what true airspeed means. The true speed the plane is going through the air to compensate the lower air density is always higher as what your airspeed indicator shows you in your cockpit, the higher you are. To not have to calculate constantly which true airspeed you should have per altitude to generate the required lift, the airspeed indicators in general aviation planes show the so called indicated airspeed, which is always the same, no matter the altitude, as it works independently from air density. And true airspeed does not. On the ground TAS is nearly the same as indicated airspeed, the higher you are, the faster the plane not only has to go to have the same, constant IAS, but it also can go faster, thanks to the thinner air, which produces less and less resistance the thinner it becomes, but unfortunately it also becomes less and less powerful. ... t.b.c
... And last but not least here's another example, how you can picture what's happening with the air around (mostly beneath) planes: think of a water skier (not surfer!, It have to be water skies). Both water and air (as a gas) belong to the so called fluids. Physically. Which means, they share certain physical key properties, with the most important one being the capability to yield when so called shear forces are applied. A property solid object/matter doesn't have. They can resist certain amount of forces/pressure until they break, succumb, but will never give gently way. Like when you walk through air - it yields, it gives way, or you couldn't move at all. Water does the same. Its density is just much higher. But since they are both fluids, you can see water as the thickest air ever. It's harder to walk or even rund through water, than running through air, right? But it works. Until it's too fast, the force is too high, then it can't yield fast enough and it starts to resist to the shear force applied more and more. It will still be able to somehow make way, but it becomes harder harder. Now think of speedboat races, how these boats jump and jump and sometimes even crash. On water. And people gets killed, because water then feels almost like a solid object. So, back to the water skier, the same principles why he can "go over water" apply to air and make planes fly. Newton's action-reaction law, the third law, the law of motion. Every object generates the same amount of counterforce when it gets moved, that was needed to move it in the first place. If the water skier would just go fast enough on his little water skies - which are not big enough to keep him on the surface of the water when he doesn't move, he simply sinks in, just like a plane in air without lift, just not that fast - then he could run over it. Isn't that great? If you have ever seen what they're doing there to grab a rope and let a boat accelerate them, then jumping onto the water and if the shear force applied is high enough and the mass of the water displaced per second equals their own mass, then they don't sink into the water but can stay at the surface and have fun... as long as their speed doesn't drop below the necessary speed required to push water beneath it away fast enough, so thatz the water can't give way fast enough but pushes back against the skies instead. Some of it. That's just what a plane does when it accelerates through air. Its wings are accelerating such sheer masses of air and send them downwards, the wind profiles and angle of attack helps here to give it the correct direction, that these masses push back so hard into the opposite direction, that the plane can rest or float on it, even a 380 t heavy Boeing 747, an airbus and whatnot, just like the water skier on water. Just because we can't see the air and are so used to it, being around us constantly, doesn't mean it's not there. and doesn't have tremendous power. Hurricanes, taifoons etc. remind us now and then what air can do... just the same damage as water. Planes are not flying because of the ominous law of Bernoulli - that's what they thought us 35 years ago, because pilot instructors usually haven't studied physics and just teach others what they had been taught once, quite a catch-22 - otherwise plane couldn't fly upside down and would immediately fall out of the sky, or aerobatic planes couldn't fly either, as they have symmetric wind profiles to be able to fly upside down even better, but because they are pushing a fluid around, a fluid that yields, when you're going through it slow enough, becoming more and more and more resistant, the faster you become and thus the higher the applied shear forces will become. And at a certain speed air gets even compressed. Something scientist thought wouldn't be possible, until pilots found out. The hard way at first. Means, it accumulates insomuch in front of the plane, that it eventually gives way with a big bang... the famous supersonic bang. If you have ever heard one. So, on water the speeds are much slower than through air, but water is a great example, how stiff it can become, almost as hard as concrete, which is also why you wouldn't survive a jump into it, when you're speed into it would be too high... People have died from it. And same goes for our atmosphere: when astronauts make their entry into our atmosphere coming back from space, then the shuttles of capsules or whatever they're using start even glowing, air becomes plasma, the third matter that belongs to the fluids: fluids like water, gas like air and plasma like... plasma. :D Now compare the speeds of the water skier with the speeds of a plane. The higher the fluid's density the slower you can be to generate the same effect. Which is why planes have to be much faster than a water skier, or have to have much larger ... skies ... (their wings obviously) or both, in order to create the same effect, so that the air's reactio equals the plane's actio => moving mass attacking another mass - Newton would probably say. And now the other way round: The higher the density - like water's - the slower you have to be (the water skier) - and the lower the density, the faster you have to be (the plane) - and the yet lower and lower the fluids density becomes (at higher and higher altitudes) ... the faster and faster the plane has to go to not lose lift. Higher true airspeeds at higher altitudes and higher possible ground speeds too. That's all there's to it. Actually easy peasy, right? 😁 To all these people only the speed through the fluid matters in order to survive their ... stunts. Not the ground speeds. The latter is of interest for normal people if they want to know, when they will reach point B after they've left point A. And in this respect it also matters for airlines and all other engine driven plane pilots, as this time determines if they will be run out of fuel before they've got to B or not. If you ever happened to have flown with an airline, you're probably familiar with estimated times of arrival (ETAs). Pilots can never say for sure when they will arrive, as headwind will slow them down (in relation to the ground!) and tailwind will speed the process up. And the latter quite a bit, if they used so called jet streams at the high altitudes airliners are operating at. They're reliably constant enough and help them saving fuel, as they help to get faster from A to B. If you hit them in the correct direction, though. You wouldn't want to swim against the tide, would you? Same effect. The river coming from in front makes it tremendously harder to cover any reasonable distance. But for a plane it's irrelevant, to some extent. It want's to fly and not die. It doesn't want to go anywhere. It's just us. That's why we have them. :D
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If you have any question leave a comment below and I will help you out!! Happy Landings...
Vr: The speed at which the pilot begins to apply control inputs to cause the aircraft nose to pitch up, after which it will leave the ground.
My question is: why on airbus computaion EFB(electronic flight bag) there are so big margin of rotation speed in cofiguration flaps one, from 155kts till 175kts(on the same aerodrome and on the same runway)
According to formula of equation lift L = (1/2) d v2 s CL
Where:
L = Lift, which must equal the airplane's weight in pounds
d = density of the air. This will change due to altitude. These values can be found in a I.C.A.O. Standard Atmosphere Table.
v = velocity of an aircraft expressed in feet per second
s = the wing area of an aircraft in square feet
CL = Coefficient of lift , which is determined by the type of airfoil and angle of attack.
I've always heard airspeed described as the speed of the plane relative to the air and that doesn't make sense to me, but after watching this I see that it is the speed of the air moving over the wings and that makes sense.
I finally understand the difference between air and ground speed.
Hey, many thanks for watching and the comment!! I'm glad the video helped!!! I wish you a great day!!
That’s helpful!!
I got it. 90 knots. Not the first time I've tried to get these measurements straight. Thanks.
You are very welcome!
Your videos are sooo good! Your ability to simplify complicated things is amazing!
Many thanks for your kind words!
Is this True airspeed vs Groundspeed or Indicated airspeed vs Groundspeed?
The video is about the difference between the Airspeed in general and the ground speed...
Thanks for the simplified info. But I thought headwind should be a minus and tail wind a plus to GS?
You are welcome! Yes the higher the Tailwind the higher the GS and viceversa, at constant TAS
Just found this video will I was thinking of the difference between the two, love your style of content, subscribed!
I'm very happy you like it!! Welcome!
Thanks so much for this information sir it’s so clear now
You are very welcome
With Headwind of 10 Knots and Groundspeed of 80 Knots. The Headwind is in way resisting the forward movement of aircraft and giving lift and aircraft will takeoff from a shorter distance as compared to zero windspeed. My strange question is when headwind 10 knots it is 80 + 10 = 90 and not 80 -10 = 70 question 🤔 🙄. Please do reply. I know your explanation is perfectly right but please do clarify.
Headwind of 10kt theoretically gives you a higher TAS and a lower GS
I need this because my stupid pre calc vector problems don’t explain this
That's great you understood the logic behind! Thanks for watching
Brilliant video, at first when I saw you start to write on the virtual whiteboard I thought this video would be difficult to understand, great video, and I like how you use different scenarios to explain the same principle you're teaching us! All the best to you in your career!
Many thanks for your great comment! I wish you the best!
fantastic video, i am currently doing my PPL Training and hope to become a 737 pilot one day just as you! Thanks very much for the video😄
The earth is revolving from east to west direction...does this help the aircraft reach faster when traveling in the opposite direction?
It has an effect for sure..
If you fly at 80 knt (GS=TAS) with no wind, then suddenly you get 10 knts HDW. Will it reduce your GS by 10 or will in increase the TAS with 10? Also why?
The GS will be reduced not exactly by 10kt, however the TAS will increase by 10kt, only if the component is exactly headwind
at 7:46 , you find airspeed = ground speed = 80 knot with no wind , thats wrong , it should be both 70 knot because in the second one your groundspeed 80 knot with headwind.There is a contradiction between 2
Thanks for your comment
I have a question! I've seen some graphs recently of altitude and ground speed plotted as they happened. Why would you chose to plot those two together on a graph and what is it telling us when the altitude is relatively constant and the ground speed is fluctuating all over the place? Thank you.
If all factors are constant the GS should change much.. Try to see if there is any variables in the graph you saw. Have a great day
@@PILOTCLIMB Thank you. I am bugging my pilot friends about it. If I were 20 years younger, I'd be in flight school.
So if a plane's maximum speed is stated as 500 kmph, it basically refers to ground speed? Also, it seems airspeed doesn't refer to how fast the craft is moving, merely the speed at which the air is flowing over the wings?
Greetings, I am a sim pilot and I wanted to know why is it the higher you go your airspeed decreases but your ground speed increases? For example my Longitude is plying at 243 knots at 41,000 feet but it has a ground speed of 458 knots. Is the difference because the speed of sound decreases as you gain altitude?
Great!! Check the videos I made regarding TAS / IAS / MACH NUMBER... you will find them in the channel
You are the best
Many thanks for your support!
Does it mean that when you are flying at a certain TAS and you encountery a headwind, your TAS increase?
Correct
@@PILOTCLIMB thank you !
I came here to learn about air speed, only to find out that there's something called GROUND SPEED haha, thought there was only ONE speed.
Quick question. Why do planes fly faster at higher altitudes? Or do I ask if it's windier the higher you go?
Aircraft are more efficient at high altitudes and it also the wind is stronger generally
my problem is the media always talking about speed, KPH or MPH, and that is distance over time, and this is where i get confused
I hope it's a bit clearer now
Does this airspeed which you are talking about is ias or tas? Does ias changes with head or tailwind
Beautifully explained sir . Love from india
Glad you like it! Thanks for the support!
Very nice video, I subscribed and look forward to seeing your other videos! Thank you!
Hey, Welcome to the pilotclimb community!! I'm glad you liked the videos!! Many thanks for watching and the comment!!👌
Sir, please add animations so that it'll be more easy to understand.
Your videos are amazing!!
Hey, many thanks for watching and the suggestion!! I will work on that!!
Amazing , very informative!! Thank you very much captain!!
You are very welcome!!
If there was enough tailwind, could a passenger plane break the sound barrier? I hear it quite often, but then I think how can it be?
Thank you very much, this was very helpfull.
Hey, many thanks for watching!! Feel free to watch the rest of the videos in Channel and ask me any question you may have.
I wish you a great day
Gabriele
Pilotclimb
I came here because ppl in other channel arguing about the speed of plane. Now i understand why ppl there said "even she used phone to track plane speed ( with iPhone), the real speed of the plane is still faster.
Sorry for my bad English
Many thanks for watching!!
what systeme do you use to draw ?
Electronic board
Hello captain , if i am flying at fl370 at TAS of 300 knots and for example faced a headwind of 280 knots then my gs will be 20 knots so this means that my tas becomes 650 the sum of my airspeed and the speed of the airmass i flown into ?
Hey, many thanks for watching... if you subtract/add the wind component to your TAS you will get the GS. The headwind will slow you down..So, in order to calculate the new TAS you need to take this into consideration. Let me know if you still have any questions
@@PILOTCLIMB can you give an example to make it clear.. What happens to the TAS when countering a headwind ?
@@omarabdalla5626 I think you understand what is the effect of the Headwind on your TAS. If the headwind increase (due to a gust for example) your TAS will increase and, vice versa if you experience a tailwind your TAS will decrease.
@@PILOTCLIMB thank you captain but what i relly need to know is that why the TAS increased with headwind and decreased with tailwind ? And if i was flying at a flight level with a denisty just say as an example 1 and IAS of 200 and tas of 300 if the denisty changes to be 2 for example does this means that the IAS will change and so the TAS ?
Thank You!!!
You are welcome
Great explanation.
Thanks for your support!
Simple and fantastic explained
Many thanks for watching and for the kind comment! I'm glad you liked the video.
Great Video. Thanks
You are more than welcome!! Thanks for watching!!
Fantastico Thank you !
You are very welcome
great video and great explanation!
Thanks for watching! Glad you like it!
I hope this helps with my physics test
Thanks for watching! I wish you the best on your test 👍
fantastico!!
Grazie!
In your last example, what if the TAILWIND was 80kts? This would produce an airspeed of 0kts. How can the plane fly with Zero air speed?
Hey, thanks for watching, that was just an example to make sure that the difference between airspeed and Ground speed was clear.. Merry Christmas
@@PILOTCLIMB Yes I know this was just an example. What Im asking for is an explanation of the physics/math involved because it is counter-intuitive.....we generally think a plane flies "easier" or more efficiently in a tailwind, but your example shows that tailwinds actually decrease airspeed. So it would seem that in your example a pilot would have to increase thrust in a tailwind to maintain a given airspeed to prevent stall. Im sure Im missing something as Im not a pilot, but I would like to know the physics explanation of this.
@@FSUmofo I've just watched this and see your point - I totally get the first example but have a hunch that in the second example the indicated airspeed would actually be 80kts and not 70 because the 10kt tailwind would be added to the airflow - I think 70kts is just the speed the plane would need to do in order to maintain the same 80kts as the GS. In other words if the 10kt tailwind suddenly dropped off to zero then the planes indicated airspeed would drop from 80 to 70. . . Hmmm just a hunch - answers on a postcard :-)
@@FSUmofo because in real life ground speed isn't constant. In real life planes stay between "stall speed"(minimal airspeed before losing lift) and "overspeed"(max airspeed plane can handle).
So within that envelope getting tailwind actually increaces groundspeed.
Great
Thanks for watching
Isn’t tailwind pushing the plane so shouldn’t airspeed be higher?
Hey, many thanks for watching!! The tailwind pushes the plane so, the GROUNDSPEED is higher at constant Airspeed... at constant GROUNDSPEED the airspeed is lower with tailwind👍 let me know if you have any more questions..
@@PILOTCLIMB oh I see thank you! And also how do I know how fast I’m actually flying with the wind component? Altimeter shows only the airspeed correct?
The Altimeter only shows you your Altitude, on the Airspeed indicator you read the Indicated Airspeed. The sophisticated Aircrafts have the GROUNDSPEED indicated in the Navigation Display or on the FMC, however if the aircraft doesn't tell you your ground speed you can calculate it from your True Airspeed and your wind component... let me know if you need more details..
You can picture the differences easier when think of a glider, a sailplane, planes I started to learn flying with when I was 13 y/o. These planes don't have any engine to pull them through the air, they only fly because they 'fall' due to gravity, gently though, with huge wings to produce the necessary lift to not really fall out of the sky. In these planes AIRspeed matters more than in any other, or better, the plane's attitude in the air, as you can't just make up for lost airspeed - let's call it airflow for the moment - by just pushing a throttle forward to gain more airspeed, airflow around the wings, if you had lost speed. You could only push the nose down to gain more speed. Which results in a loss of altitude, whioch can lead to dangerous situtation near the ground, as you might can imagine. So, managing the planes energy state is key in soaring. There are set limits, normal and max speeds, but especially of a minimum airflow necessary around the wings and fuselage to make a plane fly. Any plane. And for my Bocian back in the days it was min 60 km/h and normal was 80 km/h. Doesn't sound really fast for a plane, right? :D And here's what could happen: if there's strong enough headwinds planes could appear as if they'd be standing still in the air, because the ground speed, the speed that is really the least important one for a piston engine plane, and especially for a sailplane, was so low, because the incoming wind from in front of the plane could generate enough lift alone in windy conditions, so that the plane was barely moving. Compared to the ground. You didn't make much of a distance in relation to the ground. So that's what matters only, it doesn't make a difference for the necessary lift, if you move the plane through the air to generate the airflow around the wings, or if the wind is moving around your static plane with the same speed. Like they test aerodynamics in windtunnels in Formula 1. The car is standing still and they blow wind against and over it, as if it was going with 300 km/h. Samey. Same they can do with wings for planes, fuselages and so on.
So, in order for the glider pilot to not exceed the max speed limits of his fragile sailplane, he cannot go just faster to go faster in relation to the ground, when his airspeed indicator tells him, that he's 'going' with 80 km/h. Unfortunately not going anywhere when the wind came with 80 km/h from in front (which was 22 m/s). That would relate in 0 km/h ground speed. If he pushed the nose down to not have to stand still up there forever, he would then gain more indicated airflow... um speed ... around his wings. Maybe 100 km/h. And this would mean he would go by 20 km/h in relation to the ground. If there's no wind at all he had to move the plane with 80 km/h to create the same airflow around the wings, which would result in 80 km/h in relation to the ground. And vice versa: when headwind slows a plane down in relation to the ground, then tailwind must make it faster. You have to subtract, not add, the tailwind from your speed through the air in order to know if you have reached the necessary airflow/speed around your wings. Tailwind is taking airflow away from your wings. Wrong direction so to speak. A plane doesn't fly with airflow from behind. It works only the other way round. The more wind from behind, the faster you have to go (in relation to the ground!) in order to compensate what tailwind takes away from you. Headwind on the other hand, adds airflow around your wings - correct direction - thus you can go slower (in relation to the ground!) in order to generate the same airspeed around your wings. It's always only about the speed of the air around your wings. This result in different speeds of the planes the have to go through the air not only in windy conditions, but also depending on the altitude, as air gets thinner and thinner the higher you go, hence you have to go faster and faster to get the same amount of air (mass) around your wings per second, to not stall and fall to the ground. This is what true airspeed means. The true speed the plane is going through the air to compensate the lower air density is always higher as what your airspeed indicator shows you in your cockpit, the higher you are. To not have to calculate constantly which true airspeed you should have per altitude to generate the required lift, the airspeed indicators in general aviation planes show the so called indicated airspeed, which is always the same, no matter the altitude, as it works independently from air density. And true airspeed does not. On the ground TAS is nearly the same as indicated airspeed, the higher you are, the faster the plane not only has to go to have the same, constant IAS, but it also can go faster, thanks to the thinner air, which produces less and less resistance the thinner it becomes, but unfortunately it also becomes less and less powerful. ... t.b.c
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And last but not least here's another example, how you can picture what's happening with the air around (mostly beneath) planes: think of a water skier (not surfer!, It have to be water skies). Both water and air (as a gas) belong to the so called fluids. Physically. Which means, they share certain physical key properties, with the most important one being the capability to yield when so called shear forces are applied. A property solid object/matter doesn't have. They can resist certain amount of forces/pressure until they break, succumb, but will never give gently way.
Like when you walk through air - it yields, it gives way, or you couldn't move at all. Water does the same. Its density is just much higher. But since they are both fluids, you can see water as the thickest air ever. It's harder to walk or even rund through water, than running through air, right? But it works. Until it's too fast, the force is too high, then it can't yield fast enough and it starts to resist to the shear force applied more and more. It will still be able to somehow make way, but it becomes harder harder. Now think of speedboat races, how these boats jump and jump and sometimes even crash. On water. And people gets killed, because water then feels almost like a solid object.
So, back to the water skier, the same principles why he can "go over water" apply to air and make planes fly. Newton's action-reaction law, the third law, the law of motion. Every object generates the same amount of counterforce when it gets moved, that was needed to move it in the first place. If the water skier would just go fast enough on his little water skies - which are not big enough to keep him on the surface of the water when he doesn't move, he simply sinks in, just like a plane in air without lift, just not that fast - then he could run over it. Isn't that great?
If you have ever seen what they're doing there to grab a rope and let a boat accelerate them, then jumping onto the water and if the shear force applied is high enough and the mass of the water displaced per second equals their own mass, then they don't sink into the water but can stay at the surface and have fun... as long as their speed doesn't drop below the necessary speed required to push water beneath it away fast enough, so thatz the water can't give way fast enough but pushes back against the skies instead. Some of it.
That's just what a plane does when it accelerates through air. Its wings are accelerating such sheer masses of air and send them downwards, the wind profiles and angle of attack helps here to give it the correct direction, that these masses push back so hard into the opposite direction, that the plane can rest or float on it, even a 380 t heavy Boeing 747, an airbus and whatnot, just like the water skier on water. Just because we can't see the air and are so used to it, being around us constantly, doesn't mean it's not there. and doesn't have tremendous power. Hurricanes, taifoons etc. remind us now and then what air can do... just the same damage as water.
Planes are not flying because of the ominous law of Bernoulli - that's what they thought us 35 years ago, because pilot instructors usually haven't studied physics and just teach others what they had been taught once, quite a catch-22 - otherwise plane couldn't fly upside down and would immediately fall out of the sky, or aerobatic planes couldn't fly either, as they have symmetric wind profiles to be able to fly upside down even better, but because they are pushing a fluid around, a fluid that yields, when you're going through it slow enough, becoming more and more and more resistant, the faster you become and thus the higher the applied shear forces will become.
And at a certain speed air gets even compressed. Something scientist thought wouldn't be possible, until pilots found out. The hard way at first. Means, it accumulates insomuch in front of the plane, that it eventually gives way with a big bang... the famous supersonic bang. If you have ever heard one. So, on water the speeds are much slower than through air, but water is a great example, how stiff it can become, almost as hard as concrete, which is also why you wouldn't survive a jump into it, when you're speed into it would be too high... People have died from it. And same goes for our atmosphere: when astronauts make their entry into our atmosphere coming back from space, then the shuttles of capsules or whatever they're using start even glowing, air becomes plasma, the third matter that belongs to the fluids: fluids like water, gas like air and plasma like... plasma. :D
Now compare the speeds of the water skier with the speeds of a plane. The higher the fluid's density the slower you can be to generate the same effect. Which is why planes have to be much faster than a water skier, or have to have much larger ... skies ... (their wings obviously) or both, in order to create the same effect, so that the air's reactio equals the plane's actio => moving mass attacking another mass - Newton would probably say. And now the other way round:
The higher the density - like water's - the slower you have to be (the water skier) - and the lower the density, the faster you have to be (the plane) - and the yet lower and lower the fluids density becomes (at higher and higher altitudes) ... the faster and faster the plane has to go to not lose lift. Higher true airspeeds at higher altitudes and higher possible ground speeds too. That's all there's to it. Actually easy peasy, right? 😁
To all these people only the speed through the fluid matters in order to survive their ... stunts. Not the ground speeds. The latter is of interest for normal people if they want to know, when they will reach point B after they've left point A. And in this respect it also matters for airlines and all other engine driven plane pilots, as this time determines if they will be run out of fuel before they've got to B or not. If you ever happened to have flown with an airline, you're probably familiar with estimated times of arrival (ETAs). Pilots can never say for sure when they will arrive, as headwind will slow them down (in relation to the ground!) and tailwind will speed the process up. And the latter quite a bit, if they used so called jet streams at the high altitudes airliners are operating at. They're reliably constant enough and help them saving fuel, as they help to get faster from A to B. If you hit them in the correct direction, though. You wouldn't want to swim against the tide, would you? Same effect. The river coming from in front makes it tremendously harder to cover any reasonable distance. But for a plane it's irrelevant, to some extent. It want's to fly and not die. It doesn't want to go anywhere. It's just us. That's why we have them. :D
Are you italian ?
Yes I am!! 👍
Airspeed equals ground speed account for wind. Altitude and the Earth rotating is never figured in that proves we don't live on a spinning ball.
Thanks for your comment!
It's just the air speed relative to the aircraft
It's just the air speed relative to the plane
Yes correct
not a pilot student, just here for our linear algebra :>
Has anyone ever successfully taken off and/or landed with zero or negative groundspeed, in a fixed-wing aircraft?
very hard to understand the pronunciation
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