more at http://scitech.quickfound.net/aviation_news_and_search.html "Army Air Forces training film. On the line maintenance, depot maintenance, and flight operation of the turbosupercharger, using a B-17 for demonstration. Explains basic principles of the induction, exhaust, cooling, control, and lubrication systems. Shows how the pilot operates the controls. General O.P. Echols speaks on the value of high altitude flying and Dr. Sanford A. Moss poses with the Collier Trophy (1941). Includes still pictures of experiments on Pike's Peak." US Army Air Forces Training Film AF-123 Reupload of a previously uploaded film, in one piece instead of multiple parts. Public domain film from the National Archives, slightly cropped to remove uneven edges, with the aspect ratio corrected, and mild video noise reduction applied. The soundtrack was also processed with volume normalization, noise reduction, clipping reduction, and equalization (the resulting sound, though not perfect, is far less noisy than the original). http://creativecommons.org/licenses/by-sa/3.0/ http://en.wikipedia.org/wiki/Turbocharger A turbocharger, or turbo (colloquialism), from the Greek "τύρβη" (mixing/spinning) is a forced induction device used to allow more power to be produced for an engine of a given size. It is formally known as a turbosupercharger, as it is a type of supercharger whose power is driven from an exhaust gas turbine The key difference between a turbocharger and a conventional supercharger is that the latter is mechanically driven from the engine often from a belt connected to the crankshaft. The benefit of a turbo is that it compresses a greater mass of intake air into the combustion chamber(s), thereby resulting in increased power and/or efficiency... History Forced induction dates from the late 19th century, when Gottlieb Daimler patented the technique of using a gear-driven pump to force air into an internal combustion engine in 1885. The turbocharger was invented by Swiss engineer Alfred Büchi, who received a patent in 1905 for using a compressor driven by exhaust gasses to force air into a piston engine. During the First World War French engineer Auguste Rateau fitted turbochargers to Renault engines powering various French fighters with some success. In 1918, General Electric engineer Sanford Alexander Moss attached a turbo to a V12 Liberty aircraft engine. The engine was tested at Pikes Peak in Colorado at 14,000 feet (4,300 m) to demonstrate that it could eliminate the power loss usually experienced in internal combustion engines as a result of reduced air pressure and density at high altitude. General Electric called the system turbosupercharging... Turbochargers were first used in production aircraft engines such as the Napier Lioness in the 1920s, although they were less common than engine-driven centrifugal superchargers. Ships and locomotives equipped with turbocharged Diesel engines began appearing in the 1920s. Turbochargers were also used in aviation, most widely used by the United States, which led the world in the technology due to General Electric's early start. During World War II, notable examples of US aircraft with turbochargers include the B-17 Flying Fortress, B-24 Liberator, P-38 Lightning and P-47 Thunderbolt. The technology was also used in experimental fittings by a number of other manufacturers, notably a variety of Focke-Wulf Fw 190 models, but the need for advanced high-temperature metals in the turbine kept them out of widespread use. Turbocharging versus supercharging In contrast to turbochargers, superchargers are not powered by exhaust gases but driven by the engine mechanically. Belts, chains, shafts, and gears are common methods of powering a supercharger. A supercharger places a mechanical load on the engine to drive. For example, on the single-stage single-speed supercharged Rolls-Royce Merlin engine, the supercharger uses up about 150 horsepower (110 kW). Yet the benefits outweigh the costs: For that 150 hp (110 kW), the engine generates an additional 400 horsepower, a net gain of 250 hp (190 kW). This is where the principal disadvantage of a supercharger becomes apparent: the internal hardware of the engine must withstand the net power output of the engine plus the 150 horsepower to drive the supercharger. In comparison, a turbocharger does not place a direct mechanical load on the engine. It is more efficient because it uses kinetic energy of the exhaust gas to drive the compressor. In contrast to supercharging, the principal disadvantages of turbocharging are back-pressure, heat soak of the intake air and the inefficiencies of the turbine versus direct-drive. A combination of an exhaust-driven turbocharger and an engine-driven supercharger can mitigate the weaknesses of the other. This technique is called twincharging...

• published: 14 Nov 2014
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