Why do air planes fly so high, often 10 km above the ground?

Question

I need to know this answer for a school activity.

Answer 1

Aircraft travel in cruise at what is known as an equivalent airspeed, which is a function of how much air is actually encountered by unit of time. Higher altitude means a reduction of air density, and to have the same dynamic pressure, an aircraft has to fly faster to get the required lift, but without really feeling it, as the drag is also maintained constant (as a function of the equivalent airspeed). So, flying high means flying at the same speed from an aerodynamic point of view, but flying much faster and efficiently from a ground point of view. That thus translates into faster, more efficient flight.

Of course, there is a limit to how high one can fly, as the speed of sound drops as one gets higher, and getting close to the speed of sound does bring its own unique type of drag.

Answer 2

Sofia is Bulgaria's capital and its largest city. Sofia was created tens and thousands of years back and today is a city that continues to develop since the country's social and economic hub and now you can have the opportunity to visit it hotelbye . Sofia preserves several important monuments to their extended and storied past. Visitors exploring the city's roads could see remnants of The Eastern Gate from the times when Sofia was Serdika and Sredets, dating from the 2nd-4th centuries CE. These stays are exhibited in the underpass joining the Presidential Palace and The Ministerial Council, surrounded by stores offering standard Bulgarian gifts and rosewater. The Saint Sofia Basilica is among the secrets of Sofia. Is one of the oldest churches in the capital and was the city's important church through the Middle Ages, and underneath the Ottomans it was applied as a mosque.

Answer 3

Up high the air is thinner. This means that over long distances the fuel needed to get them that high is more than compensated for the less air resistance when flying at altitude. It is basically done to save fuel and give cheaper flights.

Answer 4

The tradeoff between oxygen availability/engine efficiency and air resistance/speed in respect of fuel consumption for gas turbine engines favors flying at a high altitude - you get more miles for your buck. In addition FAA guidelines stipulate a minimum altitude for commercial aircraft over populated areas, and over unpopulated areas. In some locations (outside of airport areas), lower altitudes can also be reserved for slower moving aircraft, which would make air traffic control management harder if the same altitudes were combined with fast moving jet aircraft.

Answer 5

1st of all NOT all aircrafts are capable of flying at high altitudes.. it mainly depends on the ENGINE type of that particular aircraft

Commercial jets fly at high altitudes cuz the resistance provided by the atmospheric air is relatively low as we go higher . ie, the drag decreases.. cuz the air gets thinner... but this phenomenon works only in the case of GAS TURBINE engines used in commerical jets... and they are economical when operated in high altitudes...
considering the case of an aircraft having a conventional PROPELLER-DRIVEN PISTON engine.. such aircrafts cannot be operated at a heigh higher than a maximum of 12-15,000 ft (15,000 ft only if supercharged) because as the air gets thinner.. the amount of air required for the combustion decreases so hence it decreases the engine efficiency
BUT in case of a GAS TURBINE ENGINE there is a large amount of air available for combustion (ie, the Fuel :air ratio = 1:60)so it doesnt matter even if the air is THINNER so this factor is almost negligible whereas in a piston engine the fuel : air ratio is 1:16 and as we reach higher it reduces upto 1:7 or 1:8 .. which leads to incomplete burning of the fuel and a decrease in the engine power
SO the conclusion is that @ high altitudes the air resistance is very less and GAS TURBINE engines can efficiently burn the fuel @ high altutudes so it doesnt leads to a decrease in the engine power

Answer 6

They fly so high for so many reasons:
1. Less friction cos the air is thinner.
2. To avoid birds.
3. Their engines work best at high altitudes.

Answer 7

As so many have said above, jets fly at higher altitudes to capitalize on the thinner air and less drag. They also fly at higher altitudes to catch the trade winds that operate at higher altitudes which can push them along at greater speeds than if they operated without them.

Answer 8

The air higher up is thinner. Being thinner there is less air pushing against the front of the plane. So the plane can travel faster with less resistance.

Answer 9

Jet aircraft operate much more efficiently at altitude. The air is much less dense, therefore there is much less drag and less fuel is needed to maintain a given speed.

Answer 10

The higher one goes the less air, resulting in less air friction. Less fuel is burnt at high altitude