Elegence in Design

When I was in college I was introduced to the design and performance of jet engines. They are very interesting machines and they have an amazing ability to generate large forces with relatively little fuel (compared to other types of engines). Jet engines revolutionized flight and made air travel affordable for the mass transit it is used for today.
 
The air goes in the intake, is compressed going through the compressor, the fuel is added and then burned in the combustion chamber and the hot expanded gas shoots out the back powering the turbine which powers the compressor at the beginning. The high speed and hot exhaust (in this case) is what produces thrust and makes the plane go. There are a lot of variations of jet engines, but this is the basic design.

The reason the jet needs the compressor is because it is needed to increase the pressure of the air so the combustion process can work efficiently. It's like the piston in a car. It presses the air into a little space and then explodes it. The jet engine just does this constantly without a four stroke cycle.

The reason I've explained all this is, beyond the fact that it is interesting in and of itself is what it leads to when you start to speed up. The faster the jet goes the higher the air pressure is coming in the intake. Eventually the pressure gets so high that... you guessed it, it doesn't need the compressor anymore. That then logically leads to the engine not needing the turbine since it isn't needed to power the compressor.

And that ladies and gentlemen is how you end up with one of the most elegant designs of any machine that exists in my humble opinion.

The scramjet.

The scramjet is the most powerful air breathing engine in existence. It can propel an aircraft at over Mach 5. Imagine flying from LA to New York in under 3 hours. That's the kind of crazy speeds a scramjet can get.

My main point here being the elegance here is a diagram of a scramjet:
 


There are 0 moving parts. The air goes in, gets compressed just by the shape of the inlet, the fuel is injected and combusted and shoots out as super hot exhaust all without a single little moving part. Now this is hard to do. The amount of time any single particle of air is in the jet is less than a hundredth of a second. So every single aspect of the design has to be perfect.

Speeds of over Mach 5 have been achieved and a good number of companies and countries are working feverishly to perfect the technology. Mostly for military applications right now, but it could eventually enter the commercial market and make the world an even smaller place. [Here is Lockheed Martin's SR-72 concept designed to replace the SR-71 as the US's spy plane]

Sometimes engineering and design has to be complicated. However, occasionally things work out and the result is incredible elegance, and it is just beautiful.