Hot air balloon is lighter than air
and is driven not by engines, but
by heating the air which is in the envelope. Balloon always flies leeward, i.e. where the wind blows and as fast as it blows.
In
summer hot air balloon flights usually start in the mornings (5am-9am),
while termics (vertical air flows) are quiet and/or in the evenings
(6pm-9pm), when termics become quiet. In autumn - spring mornings
flights start a bit later (8am), and in the evenings - earlier (4pm).
The average duration of the flight by hot air balloon is approximately
one hour, even though technically it can fly 2-3 or even more hours.
Hot air balloon moves approximately 10-20 kilometres per hour.
It
can rise up to more than 10 kilometres height. However, a human being
after reaching height of 3 kilometres already feels lack of oxygen.
Therefore, air balloons usually do not fly very high.
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