We wingless humans have somehow come to take flying for granted.
To help us renew our appreciation of the miracle of flight, we thought it might be worth our time to explore the science behind the engineering that gets our planes in the air — and our bodies from one coast, or one continent, to another. Plus, if you’ve ever wanted to pursue an aircraft engineering career, we’ve got the scoop on how to make that happen.
The Science Behind Aircraft Design
To understand the science behind an aircraft’s ability to sustain flight — and the aircraft engineering that takes advantage of that science — you need to start with the engines. They’re not what keeps the plane in the air, though — not by a longshot.
The engines are responsible for making the plane travel at high speeds. This high speed causes the surrounding air to flow over the wings rapidly. The shape of the wings looked at in cross-section, are deliberately designed to channel the air in a particular way. The top is rounded and the bottom is flatter. Essentially, wings manipulate the air into becoming something the plane can push against, thereby keeping it aloft.
In other words, the engines keep the plane moving forward, but the wings produce the lift necessary to gain altitude. Even this is a condensed explanation of the bigger picture. To really understand how planes work, we need to apply these abstract scientific concepts to the real world. That means understanding how engineers leverage scientific principles to change our lives for the better.
How Engineers Build Planes
Engineering in the aerospace industry has quite a lot to do with air pressure and how to manipulate it. Let’s get back to wings because wing design is critical for planes getting off the ground in the first place.
As we mentioned above, most planes’ wings have a curved upper surface and a flatter lower surface. This is what channels the air. Unfortunately, you may have heard an incorrect or incomplete explanation of why wings work the way they do.
Some write-ups on this topic claim planes stay aloft because the air traveling over the curved upper surface of the wing travels further and faster than the air traveling underneath the flat bottom surface. Bernoulli’s law states that faster-moving air has a lower pressure. Consequently, the air pressure is higher beneath the wing than above it. This creates lift that takes the plane skyward. You’ll hear this type of physical design referred to as an airfoil.
This interpretation is partly true. That’s the correct understanding of Bernoulli’s famed principle, but think of paper airplanes — they don’t catapult toward the ground if they flip over in mid-flight.
The truth is, the assumption upon which this layman's explanation is based isn’t accurate. The air above the wing isn’t required to cover its greater distance in the same amount of time as the air beneath the wing. There’s no law of physics that requires this assumption to be true.
In fact, there’s a simpler and more satisfying answer. Wings part the air the way your body does as you move through a body of water. By shaping the wing in a particular way, we can turn that to our advantage.
It’s true that a plane’s wings slice through the air and allow it to pass above and beneath. The key lies in how the curved upper surface of the wing forces the same quantity of air to occupy a much larger physical space. It basically spreads it out and elongates it. This, rather than the velocity of that air, is what produces lift. If you were to compare two jars of air — one large and one small — you’d find that there is greater pressure on the air in the smaller jar.
We’ve fine-tuned the shape of our aircraft wings to deny air its tendency to travel uninterrupted in a straight line. The design of modern aircraft wings stretches out the air the plane passes through, thereby manipulating pressure until even an aircraft weighing several tons manages to haul itself into the sky. Planes don’t fly because the speed of the air above and below the wings are different — they fly because the density and pressure of the air are different and provides enough lift to overcome the drag of the plane.
Want to Become an Aircraft Engineer?
It’s true that many of us take flying for granted, but if you can believe it, Aerospace is one of the most recent branches of engineering science. It covers everything to do with spacecraft and aeronautical engineering. It also touches on some of the biggest safety concerns other industries have to contend with.
Aircraft engineering is an eminently rewarding field to find yourself in. If the idea of leveraging the forces of physics appeals to you, this might be a great line of work to pursue. In 2016, the average annual pay for an aerospace engineer was more than $109,000. What steps should you take if you want to walk this path?
If you’re in high school, you’ll want to start tailoring your course load toward this goal. Pick up physics and chemistry classes at every opportunity and keep your math skills fresh, including trig, calculus and algebra.
Anyone can pursue an entry-level job in the field with a bachelor’s degree specifically in aerospace and aircraft engineering or in a field closely tied to this industry. You may also find yourself vetted for security clearance since a lot of engineers find themselves doing work with national defense applications. Since aviation is increasingly specialized and highly regulated, you’ll need more specific industry and regulatory knowledge as you continue.
All aircraft engineers need to be aware of proper safety procedures while working. It's imperative they keep themselves safe while working with mechanical equipment and in larger manufacturing warehouses. Hearing safety is especially important while testing engines. Engineers should choose tools that reduce overall noise levels to prevent hearing loss. Additionally, engineers concern themselves with how many takeoffs and landings critical parts can sustain before wearing out.
None of these challenges are exclusive to aircraft, however, which is why other fields often covet aerospace and aircraft engineers. If you want to be a part of a surprisingly versatile corps of physics-bending engineers, keep your eyes on the sky.