What is a scram jet engine, how does it work and why people say its the fastest??

Answer 1

A scramjet is a 'supersonic combustion ramjet'. To understand its operation, it's best to look at the evolution of jet engines.

The least sophisticated, lowest power jet enjines are called pulsejets. They can be built out of metal sheet or tubing in a garage; in fact there is a fellow in New Zealand who has a website describing how to build one, and shows it being used to power cars and even has plans online to build a pulsejet-powered cruise missile guided by GPS. The German V-1 "buzz bomb" cruise missile was powered by a pulsejet, and the pulsejet's distinctive sound resulted in the name.

Next up in sophistication is a turbojet. Unlike a pulsejet, it has a continuous stream of air flowing through, leading to continuous power. It works like this: Air flows in the front of the engine, where compressor blades drive it backward, thereby increasing its temperature and pressure. The fuel is injected into the stream of hot high pressure air and ignited, making it (of course) much hotter and higher pressure still. Those hot expanding gases shoot out the tailpipe of the engine, providing thrust. On the way out the tail end of the pipe, the gases drive another turbine, which is connected by a shaft to the compressor turbine. In this way part of the energy of the engine drives the compressor stage. This is why it's called a turbojet. Turbojets have a hot, fast, dense exhaust which creates turbulence as it mixes with the cool, stationary air around the engine. That is why turbojets are very noisy and not very efficient.

Some of the shortcomings of a turbojet are addressed with turbofan engines. These are similar to a turbojet in construction, but the compressor blades are larger and they are ducted around the turbojet core. This "bypassed" air, which does not have fuel burned in it, is intermediate in temperature, pressure, and speed between the air outside and the air flowing through the core of the engine. This increases the power of the engines and makes them much quieter. Turbofan engines are the most common type of jet engine today.

The problem with turbojets and turbofans is their complexity, which limits the speeds they can attain because of drag from the turbines. The ramjet was invented to overcome this limitation. It has no turbines; it is basically a hollow tube with a cone in the front which air passes around. The ram pressure of the air entering around the cone acts like the compressor stage in a turbojet. Ramjets have less internal drag than turbojets so they can travel faster. Unfortunately, they do not work at all below high speeds since there is no ram air pressure at low speed. Ramjets require other jets or rockets to speed them up to operational speed.

A scramjet is a ramjet in which the air passing through the engine is at supersonic speed through the entire engine. Normal ramjets have to accelerate the air passing through so they travel through the engine at less than Mach 1 compared to the speed of the plane; otherwise the shockwave inside the engine causes a flameout. Scramjets are designed to work despite the shockwaves, hense "supersonic combustion". Since it can accommodate the highest speed airflow, it can power the fastest aircraft of all these engine types.

Answer 2

only one properly this second. 6. Acceleration has no longer something to do with p.c. except to envision how lengthy it takes to get there. The machines will be designed to challenge the pilot to no more advantageous than 1G and nevertheless attain their good speeds. Or the designers might want to confirm they favor to get their swifter and layout for a higher acceleration. .

Answer 3

because it has no moving parts and is very light hence its power to weight ratio is considerably higher than other jet engines

Answer 4

http://en.wikipedia.org/wiki/Scramjet

Answer 5

DON'T KNOW