Basic Flight Theory Based on 1920s Newspaper

While researching basic flight theory, I found a Korean scientific newspaper from the 1920s and decided to translate that and discuss its contents.

Part 1: What is an airplane?

Translated text: It has been common sense that we live with our feet planted firmly on the ground. But the power of the brain has conquered all nature and made possible previously unimaginable technological feats such as telecommunication, trains, photography, automobiles, radio, blimps, and planes have become an essential part of our lives and made it impossible to predict the next great invention. I would say that the epitome of 20th century human achievement is the improvement of airplanes and the innovations in radio technology. Radio communication helps aviation. Any person well-acquainted in the greatness of scientific civilization would realize that the invention of trains that traverse the plains at tens of miles per hour greatly benefitted our lives; however, when airplanes that fly at hundreds of miles per hour become a part of our everyday lives, trains may become obsolete. Even with planes becoming commonplace, they have not replaced other modes of transportation. Trains, planes, trucks, cars, and even ships specialize in different things since they are better suited to certain uses than others.

Discussion: We can see that airplanes and radio communication technologies were prevalent in the 1920s; we can even see that Chosun, a relatively primitive country at the time, had access to this information. Therefore, we can see that the sharing of information across the world had been actively happening in the 1920s.b

Two key takeaways from paragraph 1 are radio communications and aviation. In the 21st century, these two are Korea’s main industries. Radio communication-wise, Samsung and SK lead with their technologies; in the vehicle department, Hyundai and Korea air lead the industry. Thus, in the 1920s as well as today, communication and transportation take up a sizeable portion of all industries. Even as technology improves and the world we see changes, the essence of these technologies do not change significantly.

Translated text:The technological wonder was first created by chance, by the ideas of a resourceful man. Today’s planes, like the German “뉴칸스” equipped with a 1300-horsepower engine carrying 3 tonnes of cargo and 15 passengers at 100 miles an hour, was a product of an extraordinary amount of resources put into research and development. Here is how such planes came to be.

Two types of machines traverse the skies: blimps and planes. Blimps fly using the power of gasses, but airplanes do not use gas; it uses its own power to fly. Here is why the airplane flies despite having heavy machinery and engines. A key difference between the two is that blimps rely on buoyant forces and planes rely on lift. Buoyant forces generate an upwards force by taking advantage of the difference in density between air and a gas, usually hydrogen and/or helium. Thus, the size of the blimp must be gigantic in order to lift a moderately heavy object.

What do we need when flying a kite? Wind. Without wind, a kite does not fly. In situations without wind, we have to pull on the string so that the kite generates its own wind and flies. The bigger the kite, the tauter the string. This is because the string exerts a force on the kite. In these situations, the net force of the wind, the string, and gravity causes the kite to fly upwards. As the force of the wind increases, the kite will keep going up until the string snaps and the kite flies away. The primary purpose of the string is to keep the kite at such an angle that the wind hits the kite and generates lift.

The kite in this situation will not stay afloat forever; it will eventually fall to the ground. This shows that without the force of the string on the kite, the kite cannot keep flying. Airplanes take inspiration from this fact.

Discussion: When the Wright brothers first took flight in Kitty Hawk in 1901, their airplane was powered by a measly 12 horsepower engine. In just 20 years, humanity was able to invent aircrafts that used engines that were a hundred times more powerful. In just 50 more years, humanity would set foot on the moon. This put into context just how quickly technology was evolving. Who knows what we may have in a few decades?

A key difference between the two is that blimps rely on buoyant forces and planes rely on lift. Buoyant forces generate an upwards force by taking advantage of the difference in density between air and a gas, usually hydrogen and/or helium. Thus, the size of the blimp must be gigantic in order to lift a moderately heavy object.

There are three main forces that act on the kite while it flies: Gravity, Tension, Lift

The first force is obviously gravity. Gravity pulls the kite towards Earth at [9.8*mass of the kite] newtons. This is the force that the kite needs to overcome in order to take flight.

The second force is the tension of the string on the kite. The string serves to keep the kite at an angle so that the wind hitting the kite can generate an upward force.

The most important force that acts on the kite is lift. Thanks to being angled by the string, the wind hitting the kite generates an upward force called lift. If the angle is right and the winds are fast enough, the lift becomes greater than the force of gravity, resulting in a net force directed away from Earth.

Translated text: The important parts of a plane, aside from the engine and the wings, are the propeller and rudder. The wings are like a kite and the engine and propeller equate to the force due to the wind and the string, allowing the airplane to fly. The rudder works like the tail of a kite; it allows the plane to go up, go down, and turn. In other words, the force generated by the propeller causes the plane to move forwards, causing the air to hit every part of the plane’s wings, causing a force known as lift; eventually, the lift is sufficient to lift the plane off the ground. That is why the plane needs space to accelerate before taking off. If the wind does not exert a force on the wings for even a moment, the force of gravity on the plane will cause it to come crashing down. The aerodynamic resistance is closely related to lift.

However, the plane can still fly when the propeller is stopped thanks to lift; it slowly descends to the ground. This is called gliding.

Discussion: The four important parts of an aircraft are the wings, engine, propeller, and the rudder/elevator. The engine turns the propeller, which generates a force that accelerates the aircraft forwards. This in and of itself does not generate lift; this is comparable to the act of running in order to fly a kite on a windless day. The wings act like the kite itself; it generates an upwards force that allows the aircraft to stay afloat. The rudder and the elevator keeps the plane in a stable position; it serves a similar job to the string of the kite. They provide lift that can be controlled, which helps keep the plane pointed in the desired direction and orientation.

Translated text: Airplanes can be classified into two categories depending on the location of the propeller; if the propeller is on the front, it is classified as a “puller.” If the propeller is on the back, it is known as a “pusher.” Puller aircrafts are more common now because the hull of the aircraft does not interfere with the propeller’s ability to push air.

Another way airplanes can be classified is through the number of wings. A plane with one wing is a monoplane, a plane with two wings is a biplane, and a plane with multiple wings is known as a multiplane, which has three and sometimes even four wings. These multiplanes are used for transporting cargo and personnel. Planes are also classified by their inventor. By 1929, multiplanes were practically nonexistent

Discussion: Most modern aircrafts do not use multiple wings to fly. A monoplane’s wings are the most efficient in generating lift; they also have less drag than other types. Initially, monoplanes were overshadowed by biplanes because of the lower maneuverability and greater weight; however, improvements in technology have eliminated the cons.

There is another distinction in modern aircraft: how the aircraft generates a forward force. Propeller aircraft still exist, usually for hobbyists and short-range flights. It is maneuverable at lower speeds, is fuel efficient, and is easy to maintain. Another type of aircraft is the turboprop aircraft. Often used in small high-speed aircraft, they can be efficient under 725 km/h. Turbojet aircraft use jet engines to achieve high speeds. They are efficient at supersonic speeds. Another type of aircraft is the Ramjet; they are even faster than turbojet engines and are used in military fighter jets.

Technology has come a long way since the 1920s. Thanks to modern technology-like the jet engine-we can employ aircrafts in a wider variety of settings. However, some “old” technologies are still being used and have evolved to fit certain roles.