Aircraft Flight
Commercial airliners typically cruise at altitudes of 9–12 km (30,000–39,000 ft) in temperate latitudes (in the lower reaches of the stratosphere). This optimizes fuel burn, mostly thanks to the low temperatures encountered near the tropopause and low air density, reducing parasitic drag on the airframe. It also allows them to stay above hard weather (extreme turbulence).
Concorde would cruise at mach 2 at about 18,000 m (60,000 ft), and the SR-71 would cruise at mach 3 at 26,000 m (85,000 ft), all still in the stratosphere.
Because the temperature in the tropopause and lower stratosphere remains constant (or slightly increases) with increasing altitude, very little convective turbulence occurs at these altitudes. Though most turbulence at this altitude is caused by variations in the jet stream and other local wind shears, areas of significant convective activity (thunderstorms) in the troposphere below may produce convective overshoot.
Although a few gliders have achieved great altitudes in the powerful thermals in thunderstorms, this is dangerous. Most high altitude flights by gliders use lee waves from mountain ranges and were used to set the current record of 15,447 m (50,679 ft).
On October 14, 2012, Felix Baumgartner became the record holder for both reaching the altitude record for a manned balloon and highest skydive ever from 39km (128,097 feet).
Read more about this topic: Stratosphere
Famous quotes containing the word flight:
“Its shrill scream seems yet to linger in its throat, and the roar of the sea in its wings. There is the tyranny of Jove in its claws, and his wrath in the erectile feathers of the head and neck. It reminds me of the Argonautic expedition, and would inspire the dullest to take flight over Parnassus.”
—Henry David Thoreau (1817–1862)