Through your observations you will discov- er how airplanes fly and how the science of flight makes these and other aircraft look the way they do. The map below
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TABLE OF CONTENTS Looking at Airplanes How to Use This Guide . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3 Quick Reference to How Airplanes Fly . . . . . . . . . . . . . . . . . . . . . . . . .4 LetÕs Explore the Basic Principles of Flight 1903 Wright Flyer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6 A Wing that Lifts More than 2 Tons Spirit of St.Louis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8 Streamlining Pays Off Lockheed Vega . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10 Why Does It Look Modern? Douglas DC-3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .12 Jet Power! Bell XP-59A Airacomet . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .14 Speed Faster than Sound Bell X-1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .16 Dual ControlsÑfor Air and Space North American X-1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .18
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PAGE 3Lookingat AirplanesWelcome to the National Air and Space Museum HOW TO USE THIS GUIDE This guide is for visitors to use before or after they have visited the How Things Flygallery.You will compare wings,engines,streamlining,and controls on seven airplanes in the Museum.Through your observations you will discov- er how airplanes fly and how the science of flight makes these and other aircraft look the way they do. The map below will appear throughout the booklet.Each of the seven airplanes will be highlighted as you move from one to the next.The orange timeline along the top right of each page places each of the airplanes in history. GETTING STARTED Take one of the escalators from the main first-floor lobby to the second floor balcony, overlooking the Milestones of Flight gallery. To begin,position yourself in the middle of the balcony so you are facing the Wright Flyer (highlighted below). All seven aircraft explored in this booklet can be seen from this general area. SAMPLELOCATOR MAP that orients visitors to the galleries containing the seven airplanes. PIONEERS OF FLIGHTMILESTONES OF FLIGHT EscalatorAIR TRANSPORTATION XStand here to view airplanes
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PAGE 4FORCESOFFLIGHT Four forces affect things that fly: weight,lift, thrust,and drag. When an airplane flies,the wing is designed to provide enough liftfor the airplaneÕs weight. The engine provides enough thrust to overcome drag and move the airplane forward.The forces are interconnected,so a change in one affects the others.For example, increasing the weight increases the amount of lift needed.A larger wing provides more lift,but that in turn increases how much drag must be overcome,and that increases the thrust required to maintain speed. HOWWINGSLIFT Air flowing over the top surface of a curved wing flows faster and has lower pressure than the less obstructed air flowing beneath the wing.The pressure differences between the top and bottom surfaces push the wing up,lifting the airplane. Increasing the curvature of a wing or expanding the surface area increases its lifting ability. CONTROLLING AN AIRPLANE INTHREE AXES Elevators are the movable surface on an airplane that control the airplaneÕs nose in an up and down or pitchaxis.Rudders are used to control the airplaneÕs nose in a left to right or yaw axis.Ailerons (pronounced ay-L ùer-ahns) are used to control the airplaneÕs movement in a roll axisÑmoving one wing higher than the other. QuickReferenceto How AirplanesFly PitchYaw RollLiftThrustDrag Weight Faster,Lower Pressure Air Slower,Higher Pressure Air
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BASICELEMENTSOF ANAIRPLANE SPEEDIncreasing the speed of an airplane increases the lift its wing provides.At slow speeds,airplane wings need more surface area and a thicker curved cross section to provide enough lift.At faster speeds,airplane wings need less surface area,so they can be smaller and still provide enough lift. Increasing an airplaneÕs speed also increases drag or resistance to oncoming air.The overall performance of faster airplanes is improved with streamlining,which helps reduce drag. THESOUNDBARRIER As an airplane moves through the air,it makes pressure waves that radiate from it at the speed of sound,about 1,120 kilometers (700 miles) per hour.When an airplane travels at the speed of sound (Mach 1),it catches up with its own pressure waves, which bunch together into a shock wave.When an airplane travels faster than Mach 1, it flies ahead of its pressure waves,creating an oblique shock wave at its nose. PAGE 5Fuselage WingAilerons Vertical Tail Horizontal Tail Rudder Elevator
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COMPARE the large surface area of the FlyerÕs two wings with other airplanes in the gallery. Why such big wings? (After all,they donÕt have as much weight to lift as the other airplanes.) The Flyer is lighter,but it is also much slower.A slow airplane needs more surface area on its wings to provide enough lift.ThatÕs why the bicyclist- powered Gossamer Condor above you has such long wings. FINDthe engine,drive chains,and propellers that move the Flyer forward. The 12-horsepower engine is just to the right of the pilot.The engine drives the two propellers in the rear of the airplane with chains and sprockets.The propellers generate thrust,which pushes the airplane forward.The FlyerÕs airspeed was around 48 kilometers (30 miles) per hour. FINDthe movable surfaces that control the airplane. The elevator,located in front of the airplane,controls the up-and-down movement,called pitch.The rudder ,located in the rear, controls the side-to-side movement, called yaw .The wing tips twistin oppositedirections,causing one wing to dip lower than the other and the airplane to rotate,a movement called roll .The Wright brothers realized the need to control an airplane in three dimensions or Òaxes,Óand they were the first to figure out how to do it. XPIONEERS OF FLIGHTMILESTONES OF FLIGHT Stand here to view airplane You can view this airplane from this location on the second floor. PAGE 6LetÕsExploretheBasic PrinciplesofFlight
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PAGE 8NOTICE the primary fuel tanksÑthe large gray area of the fuselage in front of the door. Charles Lindbergh and the Ryan engineers had a dilemma:where to store the 1,710 liters (450 gallons) of fuel needed for the ocean cross- ing.Even though it meant the loss of his front window,Lindbergh decided it was safest to position the engine and fuel next to each other and for him to sit behind them.To look forward,Lindbergh turned the airplane and looked out the side window or used the periscope.(It is visible near the window on the other side.) LOOKat the SpiritÕs wing tip. That thickly curved top and flat underside provide lift at the SpiritÕs relatively slow speed of 137 to171 kilometers (86 to 107 miles) per hour.This speed and wing shape were typical of the time period. The wing is often called a Òhigh-lift wing.ÓWith its large fuel load, however,the Spirit needed extra lift,so the wing was made 3 meters (10 feet) longer than other Ryan models of the time. READabout how the Spiritlost weight. Even with the extra lifting ability of the SpiritÕs wing,Lindbergh still had to justify every ounce of weight. One by one he eliminated pieces of equipment and supplies:his parachute,radio,a 1.35-kilogram AWingThatLifts MoreThan2Tons XPIONEERS OF FLIGHTMILESTONES OF FLIGHT Stand here to view airplane You can view this airplane from this location on the second floor. Rudder Elevator
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PAGE 9Spirit of St.Louis Charles Lindbergh left New York in the Spirit of St.Louison May 20, 1927.He arrived in Paris 33 hours,30 minutes later. He was the first person to fly nonstop from New York to Paris. When Lindbergh first contacted Ryan Airlines in early 1927 to purchase this airplane, he knew customized design features would be necessary for a 6,400-kilometer (4,000-mile) nonstop flight.He worked closely with the engineers at each step. They calculated that 1,710 liters (450 gallons) of fuel were needed, including emergency fuel for 800 extra kilometers (500 miles). Extra fuel tanks were added,and a wing was designed to provide enough lift for the additional 1,215 kilograms (2,700 pounds) of fuel.Carburetor Heater (3-pound) carburetor heater,all food except five ham sandwiches and all but a small ration of water. He did change his mind on one item (and it wasnÕt the sandwiches!). He nearly had engine failure over the Rocky Mountains during an earlier transcontinental flight when his carburetor iced up.Begrudgingly, he had the carburetor heater reinstalled for the Paris flight.You can see it just behind the engine. TEST YOURSELF! FINDthe SpiritÕs control surfaces and compare them with the FlyerÕs. The elevator is part of the hori- zontal tail,and the rudder is part of the vertical tail.The Òwing twistingÓ has been replaced by ailerons located on both sides of the wingÕs trailing edge. 1900191019201930194019501960 Main Fuel Tank Aileron This Airplane in Time Curved Top Flat Underside
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NOTICE the VegaÕs smooth,rounded fuselage. The exterior skin is molded plywood glued to an internal frame.This construction strength- ened the fuselage,because both the skin and the internal frame provided structural support. Compare the VegaÕs fuselage with the boxy shape of the SpiritÕs .Which looks more streamlined?LOOKfor other stream- lining features on the Vega. The Vega has a ÒcowlingÓor cover on the engine and Òwheel pantsÓ on the landing gear.These alone added 32 kilometers (20 miles) per hour to the airplaneÕs maximum speed.The VegaÕs wingÑbraced inside and stronger than the SpiritÕs Ñdoes not have external supports or Òstruts.ÓAnd the VegaÕs rounded fuselage reduces wind resistance (drag) too. THINKfurther:Why was streamlining important for the Vega? An important clue lies in the VegaÕs 450-horsepower engine.It was twice as powerful as the SpiritÕs, yet its maximum speed is only 96 kilometers (60 miles) per hour more than the SpiritÕs .Additional speed means an airplane can lift more weight,but extra speed also increases wind resistance,or drag. Increased drag slows the airplane down and uses up fuel.Think of athletes who wear streamlined clothing to reduce drag. READabout a man ahead of his time. Jack Northrop always had his sights set on the future.As he developed designs to solve problems for a wood-framed Vega,he was exploring techniques for building aluminum airplanes.Perhaps most Streamlining PaysOff PAGE 10XMILESTONES OF FLIGHT Stand here to view airplane You can view this airplane from this location on the second floor. PIONEERS OF FLIGHT
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revolutionary was his design in the late 1920s for a Òflying wing.Ó Northrop presented his ideas to the U.S.Army Air Corps,but the airplane wasnÕt developed because it had a seemingly unsolvable problem with pitch control.With the advent of computer-controlled flight,the Air Force again became interested in his plans.Before he died in 1987,Northrop was invited to the unveiling of the B-2 stealth bomberÑa Òflying wingÓbased upon his designs.Pictured above is the Northorp NM-1 that was developed in 1940 and is in the MuseumÕs collection. Lockheed Vega Amelia Earhart owned this Vega between 1930 and 1933.She flew it solo across the United States and then across the Atlantic.It is one of 130 that were built,establishing the Vega as one of the first commercial successes in aviation. During the late 1920s and early Ô30s,Vegas had a reputation for being reliable and efficient. Adventurers used them to set speed and distance records and to explore the globe.Many transportation companies used them because the airplane could carry up to four passengers as well as heavy bulky cargo.Much of the VegaÕs success is due to designer Jack Northrop.He devised construction techniques that strengthened the fuselage for carrying more weight and opened up its interior for better use of the space.He also streamlined the Vega,which contributed to its overall performance. PAGE 11Wheel Pants Fuselage Cowling This Airplane in Time 1900191019201930194019501960
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