The development of winglets, as we see them today, started during the 1973 oil crisis.

我們如今所看到的翼尖小翼自 1973 年石油危機期間開始發展。

The Arab states put an Oil Embargo on the United States for providing aid to Israel during the Yom Kippur War.

當時阿拉伯國家因美國在第四次中東戰爭期間向以色列提供幫助，因而對美國實施石油禁運政策。

This caused oil prices to sky-rocket, forcing engineers to get creative to reduce fuel consumption.

此舉導致油價飛漲，迫使工程師們必須在降低油耗方面進行創新。

Enter, Richard T. Whitcomb. I could probably do an entire video on this guy's contribution to aviation, but let’s focus on his work with Winglet’s for now.

現在來說一說理查·惠特科姆這個人。我可能之後也會製作一個完整的影片來闡述他對航空業的貢獻，不過現在先讓我們來關注他在發展翼尖小翼上的成就。

Part of his inspiration came from birds that curl their wing feathers up while gliding to achieve more lift.

他的部分靈感來自於鳥類在滑行的時候，會將其翅膀上的羽毛捲曲起來以獲得更多的升力。

So he got to work testing this theory, and found that it worked exactly as he expected.

所以他便開始測試這個理論，並發現結果確實如他所預期的一樣。

Let’s take a look at the science.

讓我們從科學的角度來檢視吧。

As you probably know from watching my previous videos, planes fly by developing high pressure air under their wings and low pressure air above.

如果有看過我之前的影片，你可能會知道飛機是通過在機翼下方產生高壓，以及在上方產生低壓來飛行的。

Fluids will always flow from high pressure regions to low pressure regions, and this can cause some problems at the tips of the wing.

流體永遠會從高壓區域流向低壓區域，而這樣的現象在翼尖引發了一些問題。

High pressure air from below will bleed into the low pressure air above, creating mini tornadoes off the tips of the wing.

來自機翼下方的高壓空氣流向了上方的低壓空氣，從而在翼尖部分產生了一個個迷你龍捲風。

This is called induced drag, and it decreases the lift of the wing and increases the fuel consumption of the plane.

這被稱作誘導阻力，它會降低機翼的升力並提高飛機的油耗。

Winglet’s reduce this airflow by reducing the pressure gradient at the tips of the wings, thus making the vortices much smaller.

而翼尖小翼能通過減少翼尖的壓力梯度來減少這種氣流，從而使得渦流變得更小。

Their ultimate goal is to create a lift distribution across the wing in the shape of an ellipse.

它們的最終目的是在機翼上形成一個橢圓形的升力分佈。

This minimizes the amount of air that wants to flow over the tips of the wing, while maintaining maximum lift.

這能在保持最大升力的同時，最小化流過翼尖的氣流量。

Let’s compare some wing shapes and their lift distributions to see how this works.

讓我們比較一下一些翼型及其升力的分佈，來觀察它們是如何發揮作用的吧。

Here are 3 wing shapes. An elliptical, rectangular and triangular wing, and their lift distributions look like this.

這裡有3種翼型 ：橢圓、矩形和三角形，而它們的升力分佈是這樣的。

As you can see, the elliptical wing also has an elliptical lift distribution.

如你所見，橢圓形的機翼也有著橢圓形的升力分佈。

And this is the ideal.

這是理想構型。

The iconic Spitfire was one of the few mass produced planes in history to have this shape, as it is difficult and expensive to manufacture.

但是這種構型製造困難且價格，而標誌性的噴火式戰鬥機便是歷史上少數擁有這種翼型的大規模生產的飛機之一。

The rectangular wings lift distribution is quite high at the edges, and this leads to high levels of induced drag.

矩形機翼的升力分佈在邊緣相當高，這導致了高度的誘導阻力。

But this is the easiest shape of wing to manufacture and is mostly used in smaller, cheaper aircraft.

但這是一種最容易製造的翼型，因此常應用在較小、較便宜的飛機上。

Our last wing, a triangular wing has high lift in the center, which rapidly drops off towards the edge.

我們的最後一種機翼，三角形的機翼在中央有著較大的升力，但是在邊緣處升力迅速降低。

This type of wing has low induced drag, but its lift distribution is far from ideal.

這種翼型有著較低的誘導阻力，但是其升力分佈則不盡理想。

So the ultimate goal is to tailor the lift across the wing into the shape of an ellipse to maximize lift and minimize induced drag.

所以最終的目標是使機翼上的升力分佈形成橢圓形，將升力最大化而將誘導阻力最小化。

Winglets are just one way to do this.

翼尖小翼只是實現這個目的的一種方式。

Boeing's latest plane, the Boeing 787 Dreamliner, has done away with winglets in favor a raked wingtip, which sweeps the tip of the wing backwards.

波音在最新客機 787 「夢幻客機」上摒棄了翼尖小翼，並用一種向後傾斜的翼尖代替。

Boeing have said that their raked wingtips have improved fuel efficiency by 5.5% over the 4.5% for conventional wingtips.

波音表示他們這種傾斜的翼尖將燃油效率提升了 5.5%，超過了傳統翼尖的提升率 4.5%。

You can learn why this alters the lift distribution by watching my video: "Why are plane wings angled backwards?"

你可以通過觀看我的影片「為什麼機翼要向後掠？」來學到這種設計是如何改變了升力分佈。

If you'd like to learn more about the costs of air travel, check out this quick preview for a video Wendover Productions that I worked on.

如果你想知道更多有關航空旅行成本的知識，看看我與 Wendover Productions 一同合作製作的影片的簡短預覽介紹吧。

An Airbus A320 burns 1.5 gallons of jet fuel for every mile it flies, so flying the 213 miles from New York to D.C. burns 317 gallons, or about 2 gallons per person.

一台空中巴士 A320 每飛行一英里要耗費 1.5 加侖的航空燃油，因此一趟從紐約到華盛頓特區的 213 英里旅程將要耗費 317 加侖的燃油，也就是機上每個人 2 加侖的燃油。

Given average jet fuel prices, it only costs 2.50$ in fuel for you to fly from New York to D.C., so why do tickets cost upwards of $80?

以航空燃油的平均價格來計算，乘客搭乘從紐約飛往華盛頓特區的航班只需花費 2.5 美元的燃油費用，所以為什麼機票會要價 80 美元呢？

Well, the short answer is takeoff fees, landing fees, crew costs, taxes, more taxes, airplane fees, maintenance fees, insurance costs, even more taxes, and administrative costs.

這個嘛，簡短的答案是當中包含了起飛費用、降落費用、機組員成本、稅、更多的稅、飛機本身的費用、保養費用、保險成本、甚至更多更多的稅，還有管理成本。

If you want the long answer? Well then come over to my channel and watch my video, which includes a special appearance by Real Engineering.

你想聽長一點的解釋嗎？那就來我的頻道看看並觀賞我的影片吧，在其中 Real Engineering 也會做為特別嘉賓出現喔。