Why do modern flights take longer than in the past?
How long does a direct flight take from Dubai to London? If we are talking about day trips, the usual answer is between 7 and a half to 8 hours. But the answer differs greatly if we are talking about the past decades. At one time, the same flight was possible within a shorter time, and in some cases within only 3 hours.
It may seem strange that we are used to things evolving with time, but in the field of aviation, the speeds of aircraft went in reverse in fact, as aircraft were flying faster during the sixties and seventies than they are today. And if you're looking for the reason, the short answer here is money in the first place.
Today, almost all commercial aircraft are governed by speed limits, with speeds usually limited to 850 kilometers per hour. But in the past, these limits did not really exist, but rather came with time.
Concorde aircraft and supersonic travel
At the end of the sixties, British-French cooperation led to the creation of an aircraft called Concorde, and unlike commercial aircraft at the time, these aircraft were to travel at enormous speeds of up to Mach 2 (about 2,180 km/h), twice the speed of sound. Beginning in 1976, Concorde was the world's fastest commercial airliner.
In that era, the basic idea was that the future of aircraft (as well as other areas of transportation) would be aircraft that offer higher speeds. For Concorde it was perfect. The plane was able to travel from Dubai to London, and then cross the Atlantic to New York in just 6 hours, less than the time needed for other planes to finish even the first flight.
The main problem with Concorde was that it was too expensive to operate, as the plane dispensed fuel very quickly compared to other planes, and with the addition of its low capacity: only 100 passengers, the plane was very expensive to operate and therefore ticket prices were many times greater than regular planes.
For comparison, the data in the table below compares the costs of a Concorde to the Boeing 787 Dreamliner:
The main idea of the Concorde was great speed, but despite the great speed that the passengers were getting, the plane was very cramped and had very small seats and similar to the economy class seats in other planes, so the sacrifice of some speed was enough to get the passengers seats Several times larger and cost less than half the price of Concorde tickets.
Over the course of its operation, Concorde aircraft have always been a loser, with flight costs always greater than the revenue from ticket prices. By 2003, the Concorde had been completely discontinued and had become only a part of history.
Why are modern planes limited to a speed of about 850 kilometers per hour?
As for the jet engines in use today, most of these engines are able to achieve speeds above 1,000 kilometers per hour in reality, but despite this, aircraft do not reach that speed, and the reason here is purely economic in fact.
For aircraft, the main factor in determining flight speed is usually the air resistance to which the aircraft is exposed, as this resistance remains as a linear succession at low speeds up to Mach 0.8 (ie 80% of the speed of sound), and here the air currents around the fuselage begin to form In an unstable manner, where there are infrasound and ultrasonic currents. As a result of the lack of harmony, the plane suffers from instability on the one hand, and a much greater air resistance than usual.
In fact, the velocity range between Mach 0.8 and Mach 1.2 is the worst in terms of air resistance, meaning that an aircraft flying at Mach 1 uses less fuel than its counterpart flying at Mach 1.5. Thus the most economically appropriate speeds are either below Mach 0.8 or above Mach 1.2. For commercial aircraft, lower speeds are preferred due to the shock wave phenomenon when the sound barrier is broken.
Shock Waves Problem
If you live near a military air base, you probably know the shock waves caused by breaking the sound barrier well. As objects that fly or move at a speed greater than the speed of sound produce intense waves resulting from the rapid compression of the air in front of them.
The shock waves cause intense vibrations that may shatter the glass of nearby windows, and they also emit strong sounds similar to the sounds of explosions. The usual explosion sounds are actually shock waves generated by the explosion of a substance.
Shock waves usually range over great distances, and in some cases they can be heard tens or even hundreds of kilometers from where they are coming from. While regular aircraft cause a lot of inconvenience to residents, supersonic aircraft cause more inconvenience to any residential place they pass over.
Indeed, during Concorde's lifetime, the aircraft was prohibited from flying on most flight routes, but the vast majority of its flights took place between the coasts of Western Europe across the Atlantic to the East Coast of the United States, remaining above the ocean for almost the entire flight.
In sum, with time it became clear that trying to speed up air travel is a futile idea in general, as it is not required enough, and it is uneconomical for airlines as well.
Over the years, the focus of aircraft companies has shifted to reducing their prices to a minimum. As a result, flying today is cheaper than ever, and after it was exclusive to the wealthy and businessmen for decades in the past, it is now available to almost everyone.
Although we may never see commercial flights faster than today, the field of aviation has never stopped progressing, but the standards of its progress have moved from speed to simply economic, and perhaps this is a trend for the better.
As in cars, trains, or even ships, planes have more economic speed ranges than others, meaning that the plane consumes less fuel for the distance within certain speed ranges, and if it flies slower and faster than the field, it suffers from increased fuel consumption.