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| {{Dablink|For other uses, see [[Tailwind (disambiguation)]]}}
| | == still in front of the endless void == |
| {{Unreferenced|date=November 2009}}
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| {{Wiktionary|tailwind}}
| | Shook his head, still in front of [http://www.nrcil.net/fancybox/lib/rakuten_LV_107.html ルイヴィトンルイヴィトン] the endless void, a seeing no end in sight.<br><br>'Om ......'<br><br>out of thin air, and there is no sign.<br>Luo Feng<br>appeared around a thousand kilometers in diameter about space swirl, swirl powerful space force formed oppression, [http://www.nrcil.net/fancybox/lib/rakuten_LV_17.html ルイヴィトン キャップ] so [http://www.nrcil.net/fancybox/lib/rakuten_LV_85.html ルイヴィトン 日本] Feng Luo [http://www.nrcil.net/fancybox/lib/rakuten_LV_3.html ルイヴィトン限定財布] encountered at sea as if a hurricane like a small fishing boat, could not break free.<br><br>'killing Miss wings.' [http://www.nrcil.net/fancybox/lib/rakuten_LV_16.html ルイヴィトンのバック] Luo Feng wings rapidly, killing the driver Wu wings which, by [http://www.nrcil.net/fancybox/lib/rakuten_LV_65.html ルイヴィトン 財布 モノグラム] virtue of the law is now sentiment, had this very complicated but it is killing countless silk wings Wu channeling even, had extraterritorial battlefield Luofeng only able to drive Wu wings killing change the uppermost layer belonging to the first form.<br><br>this time with more silk Luo Feng-driven [http://www.nrcil.net/fancybox/lib/rakuten_LV_38.html ルイヴィトン ジッピーオーガナイザー] rule, killing Miss wings even laugh! Laugh! Laugh! All edges of the wings actually stretched [http://www.nrcil.net/fancybox/lib/rakuten_LV_82.html ルイヴィトン バッグ 中古] thinner, and becomes golden. Before a feather wings as if ordinary feathers, but nothing sharp edges. Available at the moment, but fine long front wings |
| | | 相关的主题文章： |
| A '''tailwind''' is a [[wind]] that blows in the direction of travel of an object, while a '''headwind''' blows against the direction of travel. A tailwind increases the object's speed and reduces the time required to reach its destination, while a headwind has the opposite effect. Tailwinds and headwinds are commonly measured in relation to the speed of vehicles — commonly air and watercraft — as well as in [[running]] events — particularly [[Sprint (race)|sprints]].
| | <ul> |
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| In aeronautics, a headwind is favorable in [[takeoff]]s and [[landing]]s because an [[airfoil]] moving into a headwind is capable of generating greater [[lift (force)|lift]] than the same airfoil moving through tranquil air or a [[tailwind]] at equal [[ground speed]]. As a result, [[aviator]]s and [[air traffic controller]]s commonly choose to take off or land in the direction of a [[runway]] that will provide a headwind. In sailing, a headwind may make forward movement difficult, and necessitate [[tacking (sailing)|tacking]] into the wind.
| | <li>[http://www.itxuefu.com/home.php?mod=space&uid=11978 http://www.itxuefu.com/home.php?mod=space&uid=11978]</li> |
| | | |
| ==Aeronautics calculations==
| | <li>[http://bbs.u686.com/forum.php?mod=viewthread&tid=10144 http://bbs.u686.com/forum.php?mod=viewthread&tid=10144]</li> |
| ===Headwind component===
| | |
| Pilots calculate the Headwind Component, Tailwind Component and Crosswind Component of any wind, if they do exist. The direction of wind is calculated using [[wind sock]]. Headwind and Tailwind are cosine functions of the wind while Crosswind Component is a sine function. Headwind and Tailwind do not occur together in normal conditions. Determining the [[ground speed]] of an aircraft requires the calculation of the head or tailwind.
| | <li>[http://kn2001.s1.xrea.com/aska/aska0.cgi http://kn2001.s1.xrea.com/aska/aska0.cgi]</li> |
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| Assume:
| | </ul> |
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| <math>A=\text{Angle of the wind from the direction of travel} </math>
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| <math>WS=\text{The measured total wind speed}</math>
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| <math>CW=\text{Crosswind}</math>
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| <math>HW=\text{Headwind}</math>
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| Then
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| <math>CW=\sin(A) \cdot WS</math>
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| <math>HW=\cos(A) \cdot WS</math>
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| For example: if the wind is at 24015 that means the wind is currently from heading 240 [[Degree (angle)|degrees]] with a speed of 15 [[Knot (unit)|Knots]] and the aircraft is taking-off from runway 18, giving it a heading of 180 degrees. Then <math>A=60^\circ</math>, and
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| <math>\text{Crosswind} = \sin[60^\circ] \cdot 15 \mathsf{knots} \approx 13 \mathsf{knots}</math>
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| <math>\text{Headwind} = \cos[60^\circ] \cdot 15 \mathsf{knots} \approx 7.5 \mathsf{knots} </math>
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| The aircraft is said to have 13 knots of crosswind and 7.5 knots of headwind.
| |
| Aircraft usually have maximum headwind and crosswind components which they cannot exceed. If the wind is at eighty degrees or above it is said to be full-cross. If the wind exceeds 90 degrees it is common practice to takeoff and land from the opposite side of the runway, it has a heading of 360 in the above mentioned example.
| |
| | |
| ===Tailwind component===
| |
| Pilots calculate the Headwind Component, Tailwind Component and Crosswind Component of any wind, if they do exist. Headwind and Tailwind are cosine functions of the wind while Crosswind Component is a sine function. Headwind and Tailwind do not occur together in normal conditions.
| |
| | |
| Assume:
| |
| | |
| <math>A=\text{Angle of the wind from the direction of travel} </math>
| |
| | |
| <math>WS=\text{The measured total wind speed}</math> | |
| | |
| <math>CW=\text{Crosswind}</math>
| |
| | |
| <math>HW=\text{Headwind}</math> | |
| | |
| Then
| |
| | |
| <math>CW=\sin(A) \cdot WS</math>
| |
| | |
| <math>HW=\cos(A) \cdot WS</math>
| |
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| For example, if the wind is at 09015 that means the wind is currently from heading 090 degrees with a speed of 15 [[Knot (unit)|Knots]] and the aircraft is taking-off from runway 24; having heading of 240. We will use the runway side with less than 90 difference from wind direction, in this case Runway 06; heading 060. Here, <math>A=30^\circ</math>.
| |
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| <math>\text{Crosswind} = \sin[30^\circ] \cdot 15 \mathsf{knots} \approx 7.5 \mathsf{knots} </math>
| |
| | |
| <math>\text{Tailwind} = \cos[30^\circ] \cdot 15 \mathsf{knots} \approx 13 \mathsf{knots} </math> | |
| | |
| The aircraft is said to have 7,5 knots of crosswind and 13 knots of headwind on runway 06, or 13 knots of tailwind on runway 24.
| |
| Aircraft usually have maximum tailwind and crosswind components which they cannot exceed. If the wind is at eighty degrees or above it is said to be full-cross. If the wind exceeds 100 degrees it is common practice to takeoff and land from the opposite end of the runway, it has a heading of 060 in the above mentioned example.
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| ==See also==
| |
| * [[Crosswind]]
| |
| * [[Air navigation]]
| |
| * [[Thrust]]
| |
| * [[Wind assistance]]
| |
| * [[Wind sock]]
| |
| [[Category:Aerodynamics]]
| |
still in front of the endless void
Shook his head, still in front of ルイヴィトンルイヴィトン the endless void, a seeing no end in sight.
'Om ......'
out of thin air, and there is no sign.
Luo Feng
appeared around a thousand kilometers in diameter about space swirl, swirl powerful space force formed oppression, ルイヴィトン キャップ so ルイヴィトン 日本 Feng Luo ルイヴィトン限定財布 encountered at sea as if a hurricane like a small fishing boat, could not break free.
'killing Miss wings.' ルイヴィトンのバック Luo Feng wings rapidly, killing the driver Wu wings which, by ルイヴィトン 財布 モノグラム virtue of the law is now sentiment, had this very complicated but it is killing countless silk wings Wu channeling even, had extraterritorial battlefield Luofeng only able to drive Wu wings killing change the uppermost layer belonging to the first form.
this time with more silk Luo Feng-driven ルイヴィトン ジッピーオーガナイザー rule, killing Miss wings even laugh! Laugh! Laugh! All edges of the wings actually stretched ルイヴィトン バッグ 中古 thinner, and becomes golden. Before a feather wings as if ordinary feathers, but nothing sharp edges. Available at the moment, but fine long front wings
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