Although jet aircraft were not flown regulary until the 1940s, the idea of an engine producing power by shooting out a stream of gases and compressed air behind it goes back a long way. It is said that the British scientisr Sir Isaac Newton (1642-1727) thought of using the idea in a stream carriage as long ago 1687. Two hundred years later an aeroplane drives by steam jets was designed, although it was never built. Then, at the beginning of the ... mehr
The development of the gas turbine engines as an aircraft power plant has been so rapid that it is difficult to appreciate that prior to the 1950's very few people had heard of this method of aircraft propulsion. The possibility of using a reaction jet had interested aircraft designers for a long time, but initially the low speed of early aircraft and the unsuitability of a piston engine for producing the large high velocity ai ... mehr
Both types are driven by the engine turbine and are usually coupled direct to the turbine shaft.
The centrifugal flow compressor (fig. 3-1) is a single or two-stage unit employing an impeller to accelerate the air and a diffuser to produce the required pressure rise. The axial flow compressor (fig. 3- 7 and fig. 3-8) is a multi-stage unit employing alternate rows of rotating (rotor) blades and station¬ary (stator) vanes, to accelerate and diff ... mehr
Centrifugal flow compressors have a single or double-sided impeller and occasionally a two-stage, single sided impeller is used, as on the Rolls-Royce Dart. The impeller is supported in a casing that also contains a ring of diffuser vanes. If a double-entry impeller is used, the airflow to the rear side is reversed in direction and a plenum chamber is required
Principles of operation
The Impeller is rotated at high speed by the turbine an ... mehr
An axial flow compressor (fig. 3-7 and fig. 3-8) consists of one or more rotor assemblies that carry blades of airfoil section. These assemblies are mounted between bearings in the casings, which incorporate the stator vanes. The compressor is a multi-stage unit as the amount of pressure increase by each stage is small; a stage consists of a row of rotating blades followed by a row of stator vanes. Where several stages of compression operate in ... mehr
The combustion chamber has the difficult task of burning large quantities of fuel. supplied through the fuel spray nozzles. With extensive volumes of air supplied by the compressor and releasing the heat in such a manner that the air IS expanded and accelerated to give a smooth stream of uniformly heated gas at all conditions required by the turbine. This task must be accomplished with the minimum loss in pressure and with the m ... mehr
The turbine has the task of providing the power to drive the compressor and accessories and, in the case of engines which do not make use solely of a jet for propulsion, of providing shaft power for a propeller or rotor It does this by extracting energy from the hot gases released from the combustion system and expanding them to a lower pressure and temperature. High stresses are involved in this process, and for efficient opera ... mehr
Rockets with solid propellant
Function: A solid propellant is a monopropellant fuel-a single mixture of several chemicals (the oxidizing agent and the reducing agent or fuel). This fuel, as implied, is in its solid state and has a preformed or moulded shape. The propellant grain, this interior shape of the core is an important factor in determining a rocket\'s performance. The variables determining grain-relative performance are core surfac ... mehr
Before we examine the tariff provisions involved and get into the inner workings of the tariff classification process, a brief primer on engine technology would be helpful.
Most sources commonly define an engine as a machine or apparatus for converting energy into mechanical power or motion. The engine\'s purpose is to translate the potential energy locked in a fuel into a rotating force called \"torque\", which is a twist ... mehr
1 England or Britain
The different names of the several countries in the United Kingdom are a little bit confusing. People often talk about England or Great Britain, although they mean the United Kingdom. In fact, there is England, Scotland, Wales, Northern Ireland, Southern Ireland and the islands north-west of France.
Great Britain is the name of the island which includes England, Scotland and Wales, but does not include Northern Ireland. Wh ... mehr
Germanische Stämme der Jüten, Angeln und Sachsen hatten die Briten im 5. Jahrhundert vertrieben. Deswegen bildeten sich in England sieben kleine Königreiche.
Grundlegende Veränderungen hatte das Christentum in die noch heidnischen angelsächsischen Länder gebracht. Das war vor allem das Verdienst der Missionsarbeit des Benediktinermönchs AUGUSTIN, der von dass Erzbistum Canterbury gründete und die Bekehrung der Angelsachsen ... mehr
On the 10 of December in 1948 a revolution took place in Paris. Under the shock of war and crime against humanity the Declaration of Human Rights was passed by the General Assembly of the United Nations. This declaration should be the beginning of a new era. It laid down the rights of everyone and told governments to respect and protect these rights.
But about 50 years later the Declaration of Human Rights is more than only a patient paper.
Welton Academy - a new school year starts for the students, especially for
Todd Anderson, a transfer student who has changed from his old school to
graduate on this elitist institute. The expectations are high and everybody
tries to live up to them.
There is more new at Welton, Mr John Keating, the new English professor, who
himself is a graduate of this school. Nobody expected, what this new teacher
was able to reach with his very ... mehr
The book begins with two men, Mr. Utterson and his cousin Mr. Richard
Enfield, on a walk in London. Although the two men are initially silent,
after passing a mysterious door , Mr. Enfield tells the lawyer, Mr Utterson,
a strange occurrence that centred around the door. Late one night, while he
was on his way home, he chanced to see an act of violence, a short man who
walked on a girl who was on her way to get a doctor. ... mehr
George Orwell (Eric Arthur Blair) was born in 1903 in India. In 1907 he came to England with his parents. From 1922 to 1927 he served with the Indian Imperial Police in Burma and wrote his first novel \"Burmese Days\" in 1934. Then he worked as a teacher and bookshop assistant and after he had seen the mass unemployment in Lancashire and Yorkshire he wrote \"The Road to Wigan Pier\" where he used his experiences. In the end of 1936 he went to S ... mehr
Alice is fifteen, white, middle, class. She diets, she dates. She loves Roger but the most time he doesn't notice her. If she would ever sleep with a boy she would sleep with him. Alice hates her look. She wants to be pretty and slim. Lately she loses fascination about all things. School is boring and she doesn't even go to parties.
Her parents want to move. Her Dad is invited to become the Dean of the Political Science at - . Alice is happy ... mehr
John Grisham was born on February 8th in 1955 in Jonesboro, Arkansas. He was raised in a family of five children. During his youth he moved around a lot because his father was a construction worker. They lived in many different places, for example in Crenshaw, Mississippi. Finally the Grisham family settled in Southaven, a little town outside Memphis, when he was twelve and then he started studying at the Southaven High School.
During his school ... mehr
At the beginning of the story, Tonya Hailey, a ten year old black girl, is raped by Billy Ray Cobb and his friend Pete Willard on the way home. They injure her badly and they also want to hang her but the bough brakes and so they throw her over a bridge into a dried up river-bed.
The girl is found by a member of her family who tells her mother what had happened. Carl Lee Hailey and his wife lay an information against the two white ... mehr
The book was first published by Century in the United Kingdom in 1993. The story is told by an omniscient narrator who shifts in the point of view. The story contains fory-two chapters.
The story takes place in Memphis and tells about an eleven-year-old boy, Mark Sway, whom a secret is told where the corp of a US senator is hidden. Together with his lawyer, Reggie Love, they fight against the FBI, because th ... mehr
\"The Pelican Brief\" is a political thriller from John Grisham. It was published by \"Bantam Doubleday Dell Publishing Group Inc. / New York\" in 1992.
The story takes place in New Orleans, Washington and New York. In a cold october night two judges of the highest law-court are killed. A young law-student writes a file about her theory of the murders. But she doesn´t know how dangerous this file is for eve ... mehr