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A Brief History of Aviation Technology This is just a summary of trends in the history of progress in aviation, so that we have a framework to study the technology, when we get to it. From Montgolfier to Mach 7 in 2000 words or less. Balloons were first developed in China as children’s toys in the 2nd or 3rd century AD, essentially bags filled with hot air from a small fire. The first such balloons in Europe were made by Bartolomeu de Gusmão in 1709. Balloon technology was further developed in Europe over the 1700s; Balloons were flown first unoccupied, then carrying animals, and finally manned in 1783: François Pilâtre de Rosier, in a Montgolfier hot air balloon, followed by Jacques Charles and Nicholas Louis-Robert in their hydrogen balloon a few days later. Of course balloons are not powered and thus fly at the whim of the wind. Why not fit them with control systems and engines? Giffard flew the first dirigible in 1852, maintaining France’s position on the cutting edge of aviation. Others, like Santos Dumont, developed fast, maneuverable dirigibles throughout the late 1800s, mostly in France (and then Zeppelin in Germany). This led to a practical-flight-mindedness in France which later allowed the French to embrace and develop the earliest airplanes. Although balloons get off the ground for a totally different reasons than airplanes do, balloons also require light, stiff materials. Dirigibles, especially (which have a structure, engines, propellers, and control systems much like those of airplanes), incorporate and helped to develop many of the technologies which would later be essential for building successful early airplanes.
Above, a picture of the Montgolfier balloon. Notice how it is heated by a fire in the launch platform, so it does not produce new hot air during flight – it stays in the air only for as long as it takes to cool
Above, Jacques Charles’ hydrogen balloon, flown about 10 days later, also in Paris.
Above, an early Giffard-like dirigible.
Above, two Santos Dumont dirigibles But bird-like flight requires wings. After many failed attempts, people throwing themselves from rocks and cliffs with small wings strapped to them, it was realized that very large, very light, and very stiff wings were needed. From 1800 to 1810, George Cayley studied the nature of wing lift and stability, making large unmanned gliders and publishing papers now recognized as the founding of modern aerodynamics. Throughout the mid 1800s, Cayley, Hansen and others built larger, unsuccessful heavier-than-air gliders and steam-powered planes, many of them ornithopters, some capable of stable descending (gliding) flight. Pilcher made many successful gliders. During the late 1800s, Otto Lilienthal made a science out of building gliders, and his designs became the most successful and controllable (and copied).
Above, a Cayley glider
Above: This “airplane” (powered glider) designed by Stringefellow, although unsuccessful, established the configuration later used in successful airplanes – wings, fuselage, propeller, tail.
Above, three Lilienthal gliders:
Above, two Wright “kites” (unmanned gliders). The one at the left is too unstable, so a tail is added for stability and control, the vertical plates seen on the kite on the right. The configuration of the Flier – elevators in the front, rudders in the back, skids at the bottom, pilot lies on lower of two wings – is already clear. Inspired by Cayley and Lilienthal, the Wright brothers studied flight control systems and the aerodynamics of wings and propellers more scientifically than ever before. This allowed them to build the best gliders yet, and then the first successful powered heavier-than-air aircraft (airplanes). Afraid their ideas (and patents, and profits and fame) would be stolen, they worked largely in secrecy and seclusion from 1900 to around 1907, when Santos Dumont (and others a few months later) independently developed successful airplanes in France. Already rich and wanting only the progress of aviation, Dumont gave away his designs to anyone willing to build or modify them. 1907-1910 saw a huge boom in aviation in France. Voisin, Depredussin, Blériot and others built many designs (and often improved each others’ designs), and many aero engines started appearing and competing. By the early 19-teens, France had air shows, air races, aero magazines and aeronautics conventions. (Most airplanes, however, were still small, light, slow and flimsy, able to carry a couple people at most. The 100mph mark had not yet been reached).
Above, the Wright “Flier”. Right; the Santos Dumont “14-Bis”, the first successful airplane in Europe, and the first airplane ever to be able to take off unassisted (no catapult or rail). The middle picture shows the 14-Bis being “flight-tested” under Dumont’s Dirigible #14 prior to the airplane’s first flight (hence the name). Because the International Aeronautics Federation requires a record-setting airplane to take off under its own power, the 14-Bis is officially the first airplane, and Dumont was technically the first man to fly a successful airplane, not the Wrights.
Above, a Voisin biplane, a Curtiss racer, and two pictures of a Blériot monoplane, the Blériot 9. Until Blériot designed monoplanes like this one, most airplanes were like the Curtiss, Voisin, Wright and Dumont designs – biplanes with pusher-propellers and some control surfaces at the very front. Blériot’s design had the engine at the front pulling the airplane, the elevator and rudders along with stabilizers at the very back (a tail), and a single set of wings, so it was more aerodynamic, more stable, safer, and easier to fly. This brilliant layout is still used in most airplanes today, and is by far the most common in all of aviation history. Then along came World War 1. Like other wars after it (WW2, Korea, Vietnam), it motivated aviation technology to make great leaps. Airplanes were used as observation platforms very early on, and soon pilots realized they could drop bombs form the relative safety of the air. Some aircraft were then designed specifically as bombers. Others were sent up to shoot them down, and the fighter (the anti-airplane airplane) was born. Fighters had to be fast and agile, so many of the technologies and techniques we today associate with aerobatics – wild maneuvers, stiff and light structures, powerful engines that work upside down, etc – were developed for WW1 fighters. In efforts to outfly and outlast the enemy, planes became faster, stronger and more powerful, and could fly farther and farther in order to penetrate behind enemy lines.
Above: The Nieuport and some Sopwith Camels (WW1 fighters) and the much larger Vickers Vimy (WW1 bomber). When WW1 ended, pilots exploited these new abilities of the airplane, setting many records for distance, altitude and endurance (Lindbergh and Earhart being two famous ones), and putting on impressive aerobatic displays all over the US and Europe with the tons of airplanes left over form WW1, often improved. So the 20s and early 30s were the “barnstorming” age of intrepid stunt-pilots and adventurers, wearing scarves, leather caps, and goggles. This was the Golden Age of aviation.
above, the Curtiss JN-4 Jenny, most barnstormers’ biplane of choice.
Above, some stunts… flying under a bridge, wingwalking, hanging from the landing gear, and transferring from one plane to another.
Above, another stunt (transferring from a car to a Jenny), and a Stearman pilot showing how “Barnstormers” advertised their arrival (and got their name).
Above,Charles Lindbergh and Amelia Earhart, and their most famous airplanes, a modified Ryan M-2 (redesigned the Ryan NYP (New York to Paris) “Spirit of St Louis”) and a Lockheed Vega.
Above, the Douglas World Cruiser, the first airplane to fly all the way around the world, taking weeks, many stops, and much maintenance. The Golden Age was also the era where many different air-race circuits and competitions pushed for sleeker, faster airplanes and more powerful engines. Designers often used exotic/experimental materials (like aluminum) and new manufacturing techniques, if that gave them the edge in speed and aerodynamics. These Air-racing technologies soon spread to military and then general aviation. New materials and much more powerful engines allowed planes in the late 30s to acquire a new look, much more streamlined, and to fly faster and higher and carry a lot more cargo. The biplane was largely forgotten (except for aerobatics and stunts), and the cantilever-wing, closed-cockpit design ideology was established, still present in today’s propeller-powered airplanes.
Above, Schneider-cup racer seaplanes, a Supermarine and a Macchi. Much of what Supermarine learned with these racers can be seen in the design of their superb WW2 fighter, the Spitfire. These technologies allowed for larger airplanes to be built, carrying many more people and much more cargo than was possible before. This was the birth of the large, relatively common airliner. Many of them were too big for any runway at the time and so were built as seaplanes, so the late 30’s and early 40’s marked the age of the huge, beautiful “clipper” seaplanes.
Above, The Boeing 314 and the China Clipper - two 1930’s airliners
Above,The North American T-6 and Curtiss P-36; early closed-cockpit cantilever-wing monoplanes representative of mid-30’s technologies and innovations from raceplanes. The late-30s/early-40s also marked the beginning of World War 2. This again pushed aviation technology to whole new levels. The cantilever-wing enclosed-cockpit propeller-powered format was pushed to its limits with turbochargers, liquid-cooling, and progressively more advanced aerodynamics. As far as airplanes in that speed range go, they got about as advanced and refined by the early 40s as they ever did, like the Mustang, Sea Fury, Bearcat and DC-3. (Large WW2 bombers and transports led to bigger runways being built all over the world, thus ending the age of seaplanes and allowing for even bigger airliners to be built).
Above, the DC-3, Mustang, Sea Fury, and Constellation – some of the best propeller-driven planes ever made. The desire for higher and higher performance led engineers during WW2 to experiment with whole new concepts and technologies. The most important one, which allowed for others to be exploited and for higher speeds to be reached, was the jet engine, pioneered by Whittle in Britain and first successfully applied by Heinkel in Germany. Along with it came swept wings, pointy noses, and again a whole new design philosophy because of the different aerodynamics at the new higher speeds. During (and just before) WW2, much of this innovative research and inventiveness was done by the Germans. (They also experimented with forward-swept wings, flying wings, stealth, cruise missiles, unmanned drones, rocket-planes, and many other ideas we today think of as “modern”).
Above, the Messerschmitt-262 and the Horten-229. The Me262 was the first jet fighter and fought in WW2 in significant numbers. The Horten flying wing only had 3 prototypes built, but it is tailless, jet-powered and stealthy, and shows the advanced stage of Nazi experimental aviation in the early 40’s. The end of WW2 allowed the US (Bell, GE, Lockheed, and NASA) and UK (Hawker, Rolls Royce) to fully realize the power of jet and rocket engines, understanding and then improving German ideas and designs, and coming up with new ones. The sound barrier was broken in 1947, and supersonic aerodynamics (which in many ways differ greatly from subsonic flight aerodynamics) started being figure out.
Above, the rocket-powered Bell X-1, the first plane to go faster than MACH 1. The period of 1945-1960 saw much, much more progress in aviation than the 43 years since. It started with propeller driven, subsonic planes and ended with the 707 and SR-71. Practically all that is known and used in the design of modern airplanes of all kinds (and even early spacecraft) came from this period, thanks to research done by Hawker, British Aerospace, Dassault, Bell, Douglas, Rockwell, Convair, Lockheed, Boeing, and others. Jet engines became more and more powerful very, very quickly, making any plane outdated within a couple years of its first flight (these fifteen years in aviation are analogous to what happened with computer technologies in the 1990s). Fueled by Cold-War paranoia, planes went faster and faster, higher and higher, and research was done to optimize performance in these new speeds and altitudes. Swept wings, area-ruled fuselages, wing twist, lift generation, anti-stall techniques, variable geometry, afterburning, air bypass, titanium, aircraft radar… Modern aviation was “invented”, and essentially ready, by 1960. In 1960, there were jet fighters and airliners that are still used today, and planes that are still the fastest and highest-flying ever.
Above: The slow, straight-winged Lockheed P-80 is representative of the early jet technology of around 1945. Just fifteen years later, Lockheed already had the SR-71, still today the fastest jet ever, and Boeing had the 707, which looks just like any airliner made today. What came later were new materials and computer technologies, as well as a lot of “crazy” experimentation, none of which really changed the way airplanes look.
Above, the X-24, M2-F3 and HL-10, lifting-body experimental airplanes that influenced spacecraft design The 60’s and early 70’s saw experimentation with lifting bodies, spaceplanes, rocketplanes, vertical-takeoff-and-landing planes, etc. Some of it had applications in spaceflight and strange military aircraft (like the Harrier, Joint Strike Fighter, and Osprey), but none of it changed the look of airplanes in general. However, the development of the high-bypass turbofan engine, perhaps the last great advancement in aero technology, did make airline flight more affordable than ever, by far. These new super-efficient jet engines, originally in the 747, made it into every last jet airliner, and the concept can also be found in every jet (even fighters) made today.
Above, high-bypass turbofans made the 747 the most fuel-efficient airliner of its time, by far. Compared to a much lower bypass ratio engine (the smaller one, below), the 747 engine (here stripped of its cowlings and casings) shows the big difference that was its great innovation: the wide turbofan: The 70’s, 80’s and 90’s saw airplanes built with new, very light space-age materials and computer aid, and also airplanes controlled with the help of computers. Airplanes made with these new materials were lighter, more efficient, and in many ways more durable. Computers allowed for the optimization and new precision levels of flight and of manufacturing, and also for the control of unstable, ultra-maneuverable fighters and of spacecraft. Out of these new technologies was born the Space Shuttle. Computers and composite materials are now making it into small general aviation aircraft.
Above: The F-16 and Space Shuttle could not have been built – and cannot be flown – without computer aid. Computer-design and space-age materials make for truly modern, yet affordable, general-aviation aircraft. These are some designs by Burt Rutan, famous for pushing aerodynamic concepts to their limits. The truly new technologies of the last 20 years have mostly military applications. One is Stealth, involving shapes and materials that make an aircraft hard to detect on radar or infrared. Another is thrust vectoring, where a jet engine ejects the air not straight backwards, but at quickly-adjustable angles, thus creating forces that help maneuver the airplane at any angle and speed.
Above; Movable thrust-vectoring nozzles, and Stealth airplanes. The future, most researchers agree, is in space. The new materials and technologies of the past couple of decades should allow for aircraft that fly into space, delivering satellites and astronauts into orbit much more cheaply and efficiently (and quickly) than cumbersome and wasteful one-time-use rockets. Where there is less air, airplanes can also go at faster speeds while experience less drag than those speeds would generate at lower altitudes, so engines that work with less air at high speeds are being developed, chasing the elusive dream of a high-altitude, high-speed airliner that can do New York to Tokyo in two hours.
Above; The X-33 “Venturestar” and X-43 “Hyper X” are the beginning of technologies that will allow airplanes to affordably fly into space, deliver satellites and/or cruise at 7-10 times the speed of sound, and land back on Earth in one piece. The idea of space tourism (sending people on recreational rides into space) also shows promise. Initiatives like the X-prize offer great rewards to someone who develops a way to send a capsule with a small number of people into suborbital space (high enough for a couple of minutes of zero-g freefall once the engines are turned off). Burt Rutan takes the lead again with the White Night, shown here. It from altitude launches a small rocket pod, known as SpaceShipOne, which rockets up to 100km carrying 3 people, then freefalls and then glides in for a landing, much like the X-15 used to.
Above; The Ryan Firebee target drone, Tupolev Tu141 Strizh spy drone, and the X-47 and X-45 UCAVs (unmanned combat air vehicles). The other latest big development in aeronautical technologies is the UAV, or unmanned air vehicle. A remote-controlled combat aircraft does not endanger the pilot’s life, so UAVs have been used as missile targets since the 40’s and as spyplanes since the 60’s. More recently, UAVs have entered more widespread use and participated in combat, first by designating/”painting” targets with lasers, and now by firing Hellfire missiles. The latest batch of experimental UAVs (including the X-47 and X-45) is stealthy, designed to carry weapons, and can fly an entire mission under autonomous computer control, requiring no real-time human guidance.
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