Each propeller is made up of two or more blades. The first propellers were made of wood, but now most propellers now are made of metal. The F4U Corsair is a propeller driven aircraft. Jet Planes - Jet planes do not have propellers.
Instead, they have jet engines that move the airplane forward through another physical principal discovered by Sir Isaac Newton - The resulting heat forces the gases out of the back of the tube at high speed. In accordance with Newton's Law, an equal force is applied in the forward direction, moving the engine and the plane it is attached to forward. These are simple explanations, and the real systems are complicated machines that are designed by specially trained engineers. If you would like to start learning more about flight and how Lift is generated by aircraft wings, you can download a free simulation program created by NASA that will let you explore this topic.
There are two programs depending on your education level - Elementary Version and Full Version. The other major control surfaces are the flaps and slats, both designed primarily to increase the lift of the wings at the slow speeds used during takeoffs and landings. Flaps are mounted on the trailing edge of the wings, slats on the leading edge.
When extended, they increase lift because they make the surface area of the wings larger and accentuate the curve of the wings. Flaps also are commonly deployed during final approach to increase lift, which provides control and stability at slower speeds. The landing gear is the undercarriage assembly that supports an aircraft when it is on the ground and consists of wheels, tires, brakes, shocks, axles and other support structures.
Virtually all jet aircraft have a nose wheel with two tires, plus two or more main gear assemblies with as many as 16 tires. The landing gear is usually raised and lowered hydraulically and fits completely within the lower fuselage when retracted.
Aircraft tires are filled with nitrogen rather than air because nitrogen does not expand or contract as much as air during extreme temperature changes, thus reducing the chances of a tire blowout. The exact number of engines on an airplane is determined by the power and performance requirements of the aircraft. Most jet airplanes have two, three or four engines, depending on aircraft size.
Some have the engines attached to the rear of the fuselage. Many have them mounted on pylons, hanging below the wings. Some have a combination of both, with an engine under each wing and one on top of the fuselage at the rear of the plane.
The power produced by the engines is controlled by the pilots, either directly or indirectly, through computerized controls. All large airliners are designed to fly safely on fewer than all engines.
In other words, the remaining engine or engines have enough power to keep the aircraft airborne. As mentioned above, some form of propulsion is required to move an aircraft through the air and generate sufficient lift for it to fly. The earliest forms of propulsion were simple gasoline engines that turned propellers. Most modern airliners are equipped with jet engines, which are more powerful and mechanically simpler and more reliable than piston engines. Jet engines first entered commercial service in the late s and were in widespread use by the mids.
A jet engine takes in air at the front, compresses it into smaller and smaller spaces, by pulling it through a series of compressor blades. Then fuel is added to the hot, compressed air and ignites the mixture in a combustion chamber. This produces an explosion of extremely hot gases out the rear of the engine and creates a force known as thrust, which propels the engine and thus the aircraft forward.
It is the same principle that propels a balloon forward when blown up with air and released. The air escaping from both a balloon and a jet engine creates a pressure differential between the front and back of the enclosed space that results in forward movement.
Importantly, as the hot gases explode out the back of a jet, they turn a wheel known as a turbine. The turbine is connected by a center shaft to the compressor blades at the front of the engine and thus keeps the compressor spinning while the engine is on. As with all combustion engines, power is increased by adding more fuel to the combustion chamber. Today's most powerful jet engines can produce more than 90, pounds of thrust. Expressed another way, each of these giant engines can lift 90, pounds straight up off the ground.
Since aircraft rely on their wings for vertical lift and engines only for horizontal movement, these large engines can lift enormous amounts of weight off the ground and power aircraft at great speeds. There are three basic types of jet engines. Turbojets are engines that use exhaust thrust alone to propel an aircraft forward, as just described.
Turbofans, or fanjets, are an improved version of the turbojet. With a larger fan at the front, the turbofan pulls in more air.
It also diverts some of the incoming air around the combustion chamber and later mixes it with the hot exhaust gases escaping out the back.
This lowers the temperature and speed of the exhaust, increasing thrust at lower speeds and making the engine quieter. The third type is the turboprop, or propjet. It uses a jet engine to turn a propeller. Thrust is generated by both the propeller and the exhaust gases of the jet itself. Turboprops are used on small, short-range aircraft such as those often operated by commuter and regional airlines.
Check out some of these related Wonders! You can also keep researching at your library and online! We're glad you having so much fun exploring Wonderopolis! Hi, Juan! The force of lift is greater than the gravity pushing down on the plane! Isn't that cool? Thanks for the feedback, Wonder Friend! The Wonder Words do work differently on the iPad.
On a computer you only have to hover your mouse over the word! Hi, Sara and Dillon! Thanks for sharing your experience and connection to this Wonder! We hope everything worked out okay! We're glad you liked this Wonder! You're in luck because we have that Wonder! Check out Wonder Are Unicorns Real? Sometimes it can be scary flying, but did you know flying is actually safer than driving! We're glad it was helpful! We hope you checked out the Wonder Word Challenge to practice!
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That's an important question, Wonder Friend! We encourage you to keep researching at your library and online! It depends on the type and size of the plane and the fuel tank! You're very welcome, Amrit! Hi, Rupinder! It's definitely important to keep good maintenance on the airplane! Safety first! Hi, Jacob! We encourage you to keep researching your question at the library and online!
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Try It Out Are you ready to soar? Be sure to check out the following activities with a friend or family member: Do you live near an airport?
Even if you don't live in a major city, chances are that there's at least a small regional or local airport near you. Ask an adult friend or family member to take you on a field trip to a local airport to watch a few airplanes take off and land.
If the only airport near you is a small regional or local airport, you may want to contact the airport in advance to find out when the best time would be to visit. Have fun watching airplanes take flight! Want to experiment with some of the basic scientific principles of flight in the comfort of your own home? All you'll need are some pieces of paper. How can you experiment with flight principles using only paper?
Make a paper airplane , of course! Experiment with different designs. How far can you get a paper airplane to fly? Have you ever flown on an airplane? If you have, write a short story describing your experience. What feelings did you experience the first time you rode in an airplane and felt it lift off the ground? But another effect also accompanies this action: the higher airflow speed atop the wing. But as always, when it comes to explaining lift on a nontechnical level, another expert will have another answer.
But he is correct in everything else. The problem is that there is no quick and easy explanation. Drela himself concedes that his explanation is unsatisfactory in some ways. So where does that leave us? In effect, right where we started: with John D. This article was originally published with the title "The Enigma of Aerodynamic Lift" in Scientific American , 2, February How Do Wings Work? Holger Babinsky in Physics Education , Vol. David Bloor. University of Chicago Press, Understanding Aerodynamics: Arguing from the Real Physics.
Doug McLean. Wiley, You Will Never Understand Lift. Peter Garrison in Flying ; June 4, Culick; July Already a subscriber? Sign in. Thanks for reading Scientific American. Create your free account or Sign in to continue.
See Subscription Options. In Brief On a strictly mathematical level, engineers know how to design planes that will stay aloft. But equations don't explain why aerodynamic lift occurs. There are two competing theories that illuminate the forces and factors of lift. Both are incomplete explanations. Aerodynamicists have recently tried to close the gaps in understanding. Still, no consensus exists.
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