Evolution of the Jet Engine Thought the course of time man has constantly sought to better both himself and mankind through creation and invention. From the first time a caveman rubbed to sticks together and discovered fire to the design and development of the Saturn 5 rocket which propelled by that same fire carried man from the earth to the moon. One can argue over whether on not this invention or that was the greatest. I intend to focus my attention on evolution of just one of those technologies the jet engine, and show the importance of its impact in our world.
In the early 1920’s, new technology was being developed to enable aircraft to fly higher and faster. This early development of aircraft technology was hindered by the depression until World War II pulled the United States out of economic hardship. Jet engine design has been critical in keeping aircraft in line with other countries’ developing technology. All over the world, countries were racing to be the first with a jet engine powered aircraft. During World War II the quest for air superiority resulted in the need for better, faster aircraft. As a result, the jet engine was created.
A simple jet engine can be described as a device that compresses large amounts of high velocity air which mixes with fuel, ignites, and then is propelled out the aft end of the aircraft. Able to keep itself going once started, the jet engine is truly a marvel of the twentieth century. Two people are credited with this wonderful invention: Dr. Hans von Ohain (German) and Sir Frank Whittle (British). Ohain actually created the first engine while Whittle was the first to acquire a patent in 1930. However, Ohain’s jet was the first to fly in 1939, while Whittle was able to get his in the air in 1941.
Ohain’s jet engine was tested in a lab in Sep. 1937 and first tested on a plane developed by Ernst Heinkel the Heinkel He178 on Aug. 27th, 1939. The Firm, Power Jets Ltd. , got a contract for Whittle’s engine, the W1, July 7th, 1939. The Maiden flight was on May 15th, 1941 with pilot Lieutenant P. E. G. Sayer flying the craft, the Gloster E28/39. The craft flew at roughly 400 mph and the engine produced 1000lbs. of thrust. After a few advances in design, the Germans came up with an air superiority jet: the Messerschmitt Me 262 powered by the Jumo 004B engine. This engine was created by Dr. Anselm Franz of the Junkers Engine Company.
At the end of WW II however, the plane, the company’s factories, and the technology were seized by the allies and aided those countries in the development of their own weapons The first jet engines in America were crafted after Whittle’s design. General Electric created the first American made engines. However, a second company, Westinghouse Corporation, built a model that included an axial compressor and annular combustion chamber, which is still the basic design today. At first these engines were used solely in fighter craft but were later introduced into spy planes and bombers and eventually commercial airliner.
One type of engine was not sufficient for all types of planes and so they modified the basic design and created the Pulse jet, the Ram jet, and the Turbine jet. The first two are reserved for the military while the Turbine Jet is used commercially, as it is a good balance of cost and speed. The Pulse jet is essentially a tube with valves at one end through which the fuel and air mixture is let in and allowed to combust, which forces the valves at the front end closed, and subsequently forces the mixture out the tail end. The valves cycle at a rapid rate allows the equivalent of one continuous combustion cycle.
The Ram Jet is the simplest of all jet engines and is essentially a pipe constricted at the middle with two open ends with a fuel injector placed in the middle. The air is taken in the front, compressed by the narrowing of the pipe, mixed with fuel and ignited, and the pressure of the compressed air behind it continues to force it out the back. It draws air while speed is controlled by the amount of fuel administered. The major downfall of this engine is that it needs another type of engine to first get it up to above 200 mph before it will even begin to operate.
The Turbine jet consists of a few large fan blades that semi-compress the air into the combustion chamber, which spins the turbine, which forces the fan around. Therefore, the Turbine jet also is able to keep itself going. One of the main advantages with Turbine jet or Turbo-fan engines is that they have an excellent thrust per engine weight ratio. In the beginning of the 1960s there was an unofficial motto of “higher and faster”. This was no more prevalent than in the production of two highly sophisticated airplanes, the SR-71 and the X-15.
Both of these airplanes marked the beginning of a new era in aviation technology, but only the SR-71 introduced a new jet engine, the J-58 axial-flow turbo jet. This engine is able to put out 32,500 lbs. of thrust, and with two of those jets the SR-71 it became the fastest and the highest-flying reconnaissance aircraft ever built. What made the airplane so amazing are the two J-58 engines. These engines made the airplane able to fly at very high altitudes, over 85,000 ft. The operation of these engines is not that complicated.
The real “magic” is in the movable inlet allowing for the jet to operate at high altitude where there is not as much oxygen in the atmosphere for the engine to use. These engines introduced the ability to use a turbo jet engine and switch to forced air technology while in flight. Another thing that was a great innovation in jet technology is the ability for an aircraft to take-off and land vertically. The first aircraft to introduce this is the Harrier, using a vector thrust engine named the F402-RR-408 turbofan. The Harrier is primarily used by the Marines, but its innovation was priceless for everyone.
The engine works as any other turbo fan, the unique characteristic about this airplane is its ability to change the angle of thrust. Meaning that instead of the thrust produced by the engine moving towards the back of the airplane the pilot can change the angle of the thrust to point toward the bottom of the airplane, allowing the airplane to takeoff and land vertically. The Harrier has been given the acronym V/STOL, meaning vertical/short takeoff and landing. This single Rolls Royce engine puts out 23,400 lbs of thrust and at altitude it can bring the airplane to 1. 25 Mach speed.
One single engine can do all this by itself amazingly enough. The way it works is by using four blowers which are what move to change the angle of thrust. Two blowers are on the front and the other two are near the rear. The front two blowers blow out cool air, and the rear two blow out hot air. Once the airplane is off the ground the pilot changes the direction of the blowers and the thrust vector propels the airplane forward. Along with uses in fighter aircraft, the jet engine has seen much advancement through the years. It has become the standard means of prolusion in cargo aircraft and also passenger liners.
The era of the 1980’s saw great advancement in jets and jet aircraft. More was learned about the potential capabilities of such a means of propulsion. As companies began to understand more about jet engines and their properties, the leaps in advancement were countless. Even now, the government has countless projects classified as top secret to keep opposing countries and even the American public unaware of our capabilities. America surged forward in its engine and aircraft development and to this day, no other country has been able to keep pace with the United States in the sky.
The newest addition to America’s arsenal of fighter aircraft is the F-22. this aircraft is simply awe-inspiring. It houses two amazingly powerful Pratt & Whitney turbo fan engines, each rated at 35,000 pounds of thrust. This thrust per engine is comparable to the engines of a trans-oceanic jetliner. Each engine is thrust-vectored on the longitudinal axis to provide greater pitch capabilities. The engines are also more than powerful enough to propel the aircraft well past the sound barrier. Because of its amazing engines, the F-22 Raptor is the epitome of what a 21st century fighter should be.
Aviation corporations are also starting to idealize and design new passenger aircraft that will revolutionize air travel. We all know of the supersonic jetliner Concorde, which carried passengers across the Atlantic Ocean faster than ever before at Mach 2. Sadly enough, this aircraft had an ill-fated destiny from the beginning and is now no longer in service. New developments will build on the foundation that the Concorde set down using new ramjets to cross oceans and continents in a matter of minutes, not hours.
The new technology which allowed for the creation of the ramjet will make it possible for a person to step onto an aircraft in London, fly to the edge of space and touch down in Sydney no more than thirty minutes later. Engines such as this are still in the developmental stage, but can be expected to begin production and service within a few decades. In addition to all this, jet engines have also been used to power helicopters and tanks which do not rely on exhaust thrust for direct power. The brave home-inventor has even dared to use it to power experimental cars.
All in all, the jet engine has greatly advanced the daily living of humans around the globe whether they realize it or not. It had become such an quintessential part of our lives much like that of the television or automobile many of us can not remember a time without it, nor can not fathom what man did before it. It has become one of the ultimate workhorses of mankind by protecting us in the air, providing fast travel, and allowing us to get to places and do things they never before dreamed imaginable.
Its impact in our world is truly incontrovertible. Works Cited Anonymous. “F-22A Raptor Advanced Tactical Fighter Aircraft US Air Force, USA”. Air Force Technology. Dec. 18th 2007. www. airforce-technology. com/projects/f22 Bilstein, Robert E. Flight in America. Johns Hopkins University Press, 1984, 1994, 2001. Bishop, Chris, ed. Air Warfare Firepower. Orbis Publishing Ltd, 1999. Rabinowitz, Harold. Pushing the Envelope Airplanes of the Jet Age. Michael Friedman Publishing Group, Inc. , 2000.