Why is commercial air travel still the same speed it was 60 years ago? And will it ever change?
In: Technology
The problem is that we started to approach the sonic barrier. The effects of the speed of sound starts to show itself in some areas at around 80% of the speed of sound. This is because the air needs to move around the aircraft body and the wings and may therefore have to go faster then the speed of sound in certain places. The problem is that when you start getting these areas of air going faster then the speed of sound you start getting a layer of high pressure air clumping up in front of the aircraft. At lower speeds this high pressure air will be able to move forward away from the aircraft but not when you start getting towards the speed of sound. The problem is that this high pressure air is pushing the aircraft back. That creates a lot more drag then normal flight. You therefore need a lot more power and use a lot more fuel to fly closer to the speed of sound. And is there anything commercial air travel does not like it is to use more money on fuel.
At around 80% the speed of sound is usually the most fuel efficient speed. Fly slower and you have to spend more fuel because the flight is longer and fly faster and you have to spend more fuel because of the increased drag. There are a few aircraft that is designed to fly faster. Of course the Concorde was designed to fly faster then the speed of sound. By going faster then the speed of sound you get rid of a lot of the issues with drag however you still need to use about twice the fuel in normal cruise and a lot more fuel punching through the sound barrier. So the Concorde was very expensive and required big fuel tanks compared to its small cabin. The price was not really its problem as its clients were not looking at the price themselves, however the cabin size was a problem. But there are a few private jets which can go faster then most commercial airliners. There are several that goes about 90% the speed of sound and a few planned ones designed to go supersonic. But these do require people who are rich enough to want to spend the massive amounts of money on fuel at these speeds.
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