Jets, Planes, and Helicopters: How Do They Fly?
Flight is a concept that has never ceased to capture human imagination. The Greeks told the story of Icarus and Daedalus, who built wings to escape captivity. Leonardo da Vinci designed several machines, centuries before the first plane, which were supposed to make flight possible for humans. Today, the fact that humans can soar into the air barely registers a second thought, which is unfortunate, as it is truly an incredible example of human ingenuity. The physics which allow planes, jets, and helicopters to fly is fascinating, and well worth learning about.
History of Planes, Jets, and Helicopters
At the beginning of the 19th century, the pursuit of flight began with Otto Lilienthal, a German engineer, who created gliders and wrote the book on aerodynamics (the study of flight) that would later inspire the Wright Brothers. The Wright Brothers, Orville and Wilbur, flew the first airplane on December 17, 1903. Airplanes developed gradually from that point on, and they were given an upgrade in the late 1930s, when the jet engine was developed and integrated into planes by Sir Frank Whittle and Dr. Hans von Ohain. The first jet plane flew in 1939, and while they were invented too late to make an impact on the outcome of World War II, the following decades saw the jet plane become the standard for commercial air flights. The helicopter actually began with a sketch by Leonardo da Vinci, but the first successful helicopter was built by Russian designer Igor Sikorsky in 1939.
- Otto Lilienthal – Before the Wright Brothers, there was Otto Lilienthal. Learn about this remarkable man and his incredible glider designs in this article from the Massachusetts Institute of Technology.
- The Wright Brothers: Invention of the Aerial Age – This online exhibition from the Smithsonian National Air and Space Museum offers a walkthrough of the invention of the first airplane, along with interactive experiments, classroom activities, and e-cards.
- Sir Frank Whittle – The National Academy of Engineering has a great biography on Sir Whittle, which also goes into detail about how jet planes have changed the 21st century.
- Hans Joachim Pabst von Ohain – The National Aviation Hall of Fame has a complete history of von Ohain and his interest in jet engines, as well as some fun facts about his personality and key achievements throughout his life.
- The Case Files: Igor Sikorsky – Discover Sikorsky and the science behind helicopters with this fun interactive case file from The Franklin Institute.
How Planes Fly
When an airplane moves forward, the wings create something called “lift”. Lift is the force of the air rushing underneath the wings of the plane. When the lift is greater than the air flow above the wings (the wings are curved on the top, so the air goes over them faster), lift overcomes the weight of the plane and pushes the airplane up. To keep the plane moving forward to generate lift, the propeller produces a force called “thrust”, which must be greater than the “drag”, or the resistance of the air to the plane. The thrust produced by the propeller is what keeps the plane moving forwards. Most airplanes are propeller driven, but some, as can be seen in the next segment, are powered by jets.
- Parts of a Plane – Planes have a lot of different parts that help them fly. To learn what these segments are called and how they work together to make a plane fly, check out this page from NASA.
- Why Airplanes Fly – This clip from the Kids Science News Network explains how airplane flight works in relation to air pressure.
- The 4 Forces of Flight – Confused about what makes lift and thrust different from one another? Check out this easy-to-understand, illustrated explanation from the Mansfield School District.
- How Airplanes Work – The University of North Carolina has a website dedicated to understanding why airplanes are able to fly, what parts make up an airplane, and for older students, the equations that determine how much thrust can be produced by an engine.
How Jets Fly
Unlike regular planes, jets do not have propellers to provide thrust. Instead, they have jet engines, which operate by burning fuel at high pressure with compressed air. The heat produced by the fuel forces gas out of the engine, which pushes the plane forward. The reason the plane moves forward is due to one of Isaac Newton’s Laws of Physics. Newton thought – and proved – that every action has an equal and opposite reaction. For example, if someone pushes on a wall, the wall provides an identical amount of force on the hand pushing it. By the same logic, as air is pushed backwards out of the engine, the air pushes the engine (and, by extension, the jet plane) forwards, effectively replacing the thrust provided by a propeller on traditional planes.
- How does a Jet Engine Work? – See an inside view of a modern jet engine and learn how a jet engine functions at this webpage from Boeing.
- Jet Engines 101 – Who better to explain how a jet engine works than the people who actually make jet engines? General Electric has an animated, interactive walkthrough of what components make up a jet engine, and how they all work together to create enough force to power a jet.
- Animated Jet Propulsion – Get a visual idea of how jets work with these simple but informative animations.
- Newton’s Third Law of Motion – What exactly is Newton’s Third Law? Find out on this page from Rice University.
- Newton’s Laws of Motion – Airplanes were designed based on these three laws of motion. Sir Isaac Newton explains his observations in this interactive lesson from Discovery.
How Helicopters Fly
Helicopters are powered by a propeller, but it isn’t on the nose of the helicopter like most propellers are on planes. A helicopter is a “rotary wing aircraft”, which means that the propeller (called the rotor) is shaped like a wing, and as it turns around, it provides the lift that the helicopter needs to fly. The rotor can tilt backwards or forwards, and it is this change in angle and lift direction that makes the helicopter move backwards or forwards. There is a smaller propeller on the tail of the helicopter that acts as a stabilizer, to keep the helicopter from spinning around with the rotations of the main rotor. Unlike regular aircraft, helicopters have the special ability to hover in one spot, which is done by keeping the rotor perpendicular to the ground and controlling the speed of the propeller rotation.
- A History of Helicopter Flight – Follow the development of the helicopter on this informative page from the University of Maryland.
- Make a Miniature Helicopter – This is a fun activity from the Exploratorium that you can do at home to see for yourself how a helicopter works.
- Is a Helicopter Engine the same as an Airplane Engine? – It’s a good question, and the Young Eagles Flight Program has the answer.
- How to Fly a Helicopter Upside Down – Helicopters aren’t designed to want to fly, so it’s fairly remarkable that someone has figured out how to make them fly upside down. Learn how it’s possible in this article from Popular Mechanics.
- Introduction to Rotary-Wing Flight – The U.S. Centennial of Flight Commission has a great article on what rotary-wing flight is, as well as a list of helicopter books to check out.
Fun Airplane Activities
- How does an Airplane Fly? (PDF) – It’s one thing to read about how a plane flies, but some of the terms and concepts may be difficult to picture mentally. To make the science real, here’s a fun, easy experiment from the National Engineers Week Foundation to try at home.
- String Rocket Races – For a fun summer activity, try making kid-friendly rockets with this tutorial from The Learning Channel.
- When Pigs Fly – This excellent interactive game offers kids the chance to build and fly their own plane while explaining the physics behind flight at the same time. It’s a great way to learn about planes “firsthand”!
- Wind, Water, and Wings (PDF) – This collection of classroom activities will help demonstrate concepts commonly found in the world of aviation, like differential pressure.
- How to Build a Styrofoam Glider – Try your hand at making a working glider with these instructions.
- Lunar Lander – Practice controlling rocket thrust with this fun game from the University of Colorado.