Historical Evaluation Unit 1

Introduction to Flight

Shiva Prasad U Assistant Professor Department of Aeronautical Engineering Guru Nanak Engineering College Hyderabad

Introduction to Flight I B.Tech Aeronautical Unit –I Historical Evaluation Text Books-1)Introduction to Flight - Jr.Anderson 2) flight with out formulae -A.C. Kermode

Syallabus • HISTORICAL EVALUTION Early airplanes, Multi planes, biplanes and monoplanes, Developments in aerodynamics, materials, structures and propulsion over the years.

Index Unit -1 PPT Slides Sr. No

Module as per Session Planner

Lecture No

     

Early Airplanes Airship Multiplane Triplane Biplane Monoplane

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Developments In Aerodynamics Developments In Materials

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Development of Aircraft Structures

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Propulsion over the years

L-1 L-2 L-3 L-4 L-5 L-6 L-7 L-8 L-9 L-10

PPT Slide No

L-1-1 to L-1-2 L-2-1 to L-2-2 L-3-1 to L-3-1 L-4-1 to L-4-2 L-5-1 to L-5-2 L-6-1 to L-6-2 L-7-1 to L-7-2 L-8-1 to L-8-4 L-9-1 to L-9-3 L-10-1 to L-10-8

Early Airplanes • • •

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First manned flight Montgolfier brothers' balloon at the London Science Museum The first clearly recorded instance of a balloon carrying passengers used hot air to generate buoyancy and was built by the brothers JosephMichel and Jacques-Etienne Montgolfier in Annonay, France. After experimenting with unmanned balloons and flights with animals, the first tethered balloon flight with humans on board took place on October 19, 1783 with the scientist Jean-François Pilâtre de Rozier, the manufacture manager, Jean-Baptiste Réveillon and , at the Folie Titon in Paris. The first free flight with human passengers was on November 21, 1783. King Louis XVI had originally decreed that condemned criminals would be the first pilots, but de Rozier, along with Marquis Francois d'Arlandes , successfully petitioned for the honor.

Montgolfier Hot Air Balloon

Airship • An airship or dirigible is a lighter-than-air aircraft that can be steered and propelled through the air using rudders and propellers or other thrust. Unlike other aerodynamic aircraft such as fixed-wing aircraft and helicopters, which produce lift by moving a wing or airfoil through the air, aerostatic aircraft, such as airships and hot air balloons, stay aloft by filling a large cavity, such as a balloon, with a lifting gas. A Zeppelin is a brand name for rigid airships historically built by either the Luftschiff Zeppelin company of Germany or the Goodyear Zeppelin company of the USA, and now of smaller semi-rigid airships built by Zeppelin Luftschifftechnik, also of Germany.

Airship

Multiplane • Multiplanes • Aircraft with four or more sets of wings are even rarer. Extreme examples include multiplanes designed by Horatio Phillips, one of which had two hundred sets of wings. Another example is the Caproni Ca.60, a oneoff transatlantic seaplane, which had three sets of triplane wings taken from Caproni Ca.4 bombers. There was also the tetra-winged (four-winged) Supermarine Nighthawk, designed to shoot down zeppelins, that never entered production.

Triplane

Triplane • A triplane is a fixed-wing aircraft equipped with three sets of wings, each roughly the same size and mounted one above the other. • Typically, the lower set of wings would be level with the underside of the aircraft's fuselage, the middle set level with the top of the fuselage, and the top set supported above the fuselage on struts. • The first triplane was designed in 1908 by Ambroise Goupy and built by Blériot, flown with a 37 kW (50 hp) Renault engine. • Triplanes have greater wing area than biplanes and monoplanes of similar wing span and chord, potentially offering increased lift and tighter turning radii.

Biplane

Biplane • A biplane is a fixed-wing aircraft with two main wings. The first powered heavier-than-air aircraft, the Wright brothers' Wright Flyer, used a biplane design, as did most aircraft in the early years of aviation. While a biplane wing structure has a structural advantage, it produces more drag than a similar monoplane wing. Improved structural techniques and materials, as first pioneered by Hugo Junkers in 1915, and the need for greater speed, made the biplane configuration obsolete for most purposes by the late 1930s.

Monoplane

Monoplane • A monoplane is an aircraft with one main set of wing surfaces, in contrast to a biplane or triplane. Since the late 1930s it has been the "ordinary" form for a fixed wing aircraft. • The term parasol monoplane, is more or less obsolete - it used to be applied to a highwing monoplane, especially one where the wing was mounted well above the fuselage.

What is Aerodynamics? Aerodynamics is branch of science which deals with the branch of the larger field of fluid dynamics that deals with the motion of air and other gaseous fluids. • It concerns the forces that these gaseous fluids, and particularly air, exert on bodies moving through it. Without the science of aerodynamics, modern flight would be impossible.

Developments In Aerodynamics • The word “aerodynamics” itself was not officially documented until 1837. However, the observation of fluids and their effect on objects can be traced back to the Greek philosopher Aristotle in 350 B.C. Aristotle conceived the notion that air has weight and observed that a body moving through a fluid encounters resistance. • Archimedes, another Greek philosopher, also has a place in the history of aerodynamics. A hundred years later, in 250 B.C., he presented his law of floating bodies that formed a basic principle of lighter-than-air vehicles.

• The next contribution to aerodynamics did not occur until the end of the 1400s. In 1490, the Italian painter, sculptor, and thinker Leonardo da Vinci began documenting his aerodynamic theories and ideas for flying machines in personal notebooks. An avid observer of birds and nature, he first believed that birds fly by flapping their wings, and thought that this motion would have to occur for manmade aircraft to rise. • He designed several ornithopters—machines that were intended to copy the action of a bird's wing with the muscle power being supplied by man. • Scientists working in the 17th century contributed several theories relating to drag. The Italian mathematician and inventor Galileo Galilei built on Archimedes' work and discovered that the drag exerted on a body from a moving fluid is directly proportional to the density of the fluid.

Leonardo da Vinci's ornithopter design.

• In 1673, the French scientist Edme Mariotte demonstrated that drag is proportional to the square of the velocity of an object (D µ V2). Dutch mathematician Christiaan Huygens had been testing this theory since 1669 and published his results with the same conclusion in 1690. The English scientist and mathematician Sir Isaac Newton presented a derivation of the drag equation of a body in 1687: Drag µ ρSV2 (where ρ is density and S is cross-sectional surface area of the body).

• Isaac Newton was one of the greatest scientific geniuses of all time and contributed to every major area of science and mathematics of his generation. He demonstrated that the universe ran according to natural laws that were understandable.

Bernoulli's Principle is a physical phenomenon that was named after the Swiss scientist Daniel Bernoulli who lived during the eighteenth century. Bernoulli studied the relationship of the he speed of a fluid and pressure.

» Bernoulli's Principle (top) says that increased air velocity produces decreased pressure. » Lift (bottom) is produced by an airfoil through a combination of decreased pressure above the airfoil and increased pressure beneath it. Daniel Bernoulli (1700Flow over an Airfoil 1782)

• Swiss mathematician Leonhard Euler, also an associate of Bernoulli, derived equations from Bernoulli's and d'Alembert's principles. The most famous of these became known as “Bernoulli's Principle.” It states that, in a flowing fluid, as velocity increases, pressure decreases. This became a key concept for understanding how lift is created. Euler also introduced equations for fluid flow, though at the time they could not be solved and applied. • Italian mathematician Joseph Lagrange and French mathematician Pierre-Simon Laplace studied Euler's findings and tried to solve his equations. In 1788, Lagrange introduced a new model for fluid flow as well as new equations for calculating velocity and pressure. In 1789, Laplace developed an equation that would help solve Euler's equations. It is still used in modern aerodynamics and physics. Laplace also successfully calculated the speed of sound.

• In addition to these theoretical advancements, experiments in aerodynamics were also producing more practical results. In 1732, the French chemist Henri Pitot invented the Pitot tube, a device that enables the calculation of velocity at a point in a flowing fluid. This would help explain the behavior of fluid flow.

Developments In Materials • Aircraft are obviously made up of different types of materials. Everything from plastics to metal alloys to composites. Most commercial aircraft nowadays are excellent examples of the advancements and developments in standard materials. • All of these materials have seen incredible improvements and refinements over the past 100 years. These recent advancements have been unheard of in any time in human history.

• So here is a slightly digested version of basic engineering materials available out there. • Basically all materials are organized into large groups or classes in the following way: • 1) Ceramics/Glasses • 2) Metals • 3) Polymers/Elastomers • 4) Composites

Ceramics/Glasses • Ceramics cover a wide range of materials that are usually very stiff, have very low ductility or formability, usually are very abrasion resistant, retain their strength and properties at very high temperatures, and also are quite corrosion resistant.

Metals • Metals are malleable and ductile (meaning they can be shaped), can be alloyed and chemically altered to almost any level of strength and stiffness, they can be tailored to have high temperature resistance, are easily heat treated and tempered, and usually very easy to machine and process.

Polymers/Elastomers • We'll quickly go over the other HUGE group of materials called polymers. Polymers have probably been the fastest growing group of materials ever. Think about the fact of how plastics, vinyl's, rubbers, etc. etc. have been integrated into everyone's life and then think back about 50 to 75 years ago and realize that they were basically completely non existent. . Composites • The final big group of materials are called composite materials. They are called this for obvious reasons in the fact that they are composites or mixtures of the other material groups to make very specialized materials

Development of Aircraft Structures • The very early airplanes were built from very lightweight materials such as bamboo, wood, and fabric. They were designed much like bridges, with beam and truss construction. • The wings on the Wright Flyer form a truss; the two wings used wires and bars diagonally (at an angle) to strengthen the wing against aerodynamic forces. • The insides of wings were also a type of truss construction. • The bars inside were called spars. Wires were used on the diagonals to strengthen the wing.

• The spars, plus the spar caps at each end, were shaped to give the wing aerodynamic features. This shape is often called the airfoil. The figure below shows the basic construction of the wing of the Sopwith Camel, World War I fighter.

The figure below shows the basic construction of the wing of the Sopwith Camel, World War I fighter.

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As manufacturing techniques for metals improved in the early 1900's, metal rods and pieces began to replace the wooden components in airplanes. Metal skins, rolled very thin, were used because they were less affected by weather than the fabric skins. The ribs and spars of the plane were made by riveting many pieces together. When aluminum alloys became available at the end of the 1920's, ribs and spars were often stamped (cut) out of whole aluminum sheets.

Propulsion over the years • Unpowered • Some types of aircraft, such as balloons, kites and gliders, do not have any propulsion. • Gliders gain their initial flying speed from some launch mechanism, and then gain additional energy from gravity and from updrafts such as thermal currents. The first practical, controllable example was designed and built by the British scientist and pioneer George Cayley who is universally recognized as the first aeronautical engineer.

Man power

Man power • The earliest designs used man power to give dirigible balloons some degree of control, and go back to Jean-Pierre Blanchard in 1784. Attempts to achieve heavier-than-air manpowered flight did not succeed until Paul MacCready's Gossamer Condor in 1977. • Gossamer Albatross, a human-powered aircraft

Powered • The first powered flight was made in a steam-powered dirigible by Henri Giffard in 1852. Attempts to marry a practical lightweight steam engine to a practical fixed-wing airframe did not succeed until much later, by which time the internal combustion engine was already dominant. • From the first powered aeroplane flight by the Wright brothers until World War II, propellers turned by the internal combustion piston engine were virtually the only type of propulsion system in use.

Propellers

• Turbine engines need not be used as jets (see below), but may be geared to drive a propeller in the form of a turboprop. • Some turboprop designs (see below) mount the propeller directly on an engine shaft, and are called propfans. • Jet propulsion • Air-breathing jet engines provide thrust by taking in air, burning it with fuel in a combustion chamber, and accelerating the exhaust rearwards so that it ejects at high speed. The reaction against this acceleration provides the engine thrust.

• Consequently, nearly all high-speed and highaltitude aircraft use jet engines. • other designs include the crude pulse jet, highspeed ramjet and the still-experimental supersonic-combustion ramjet or scramjet

Helicopters • The rotor of a Helicopter may, like a propeller, be powered by a variety of methods such as an internal-combustion engine or jet turbine. Tip jets, fed by gases passing along hollow rotor blades from a centrally-mounted engine, have been experimented with. Attempts have even been made to mount engines directly on the rotor tips.

Other Forms Of Propulsion • Rocket-powered aircraft have occasionally been experimented with, and the Messerschmitt Komet fighter even saw action in the Second World War. • Since then they have been restricted to rather specialised niches, such as the Bell X-1 which broke the sound barrier (rockets carry their own oxidant). • The flapping-wing ornithopter is a category of its own. These designs may have potential, but no practical device has been created beyond research prototypes.

References: • • • • •

http://en.wikipedia.org http://wings.avkids.com/Book www.sdsefi.com www.quest-global.com www.centennialofflight.gov