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

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

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

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.

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

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

Let’s take a look at the science.

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

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

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

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

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

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

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

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

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

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

And this is the ideal.

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.

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

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

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

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

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.

Winglets are just one way to do this.

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.

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

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

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.

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.

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?

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.

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.