Balloon Festival in Chagrin Falls, Ohio
Hot air balloons are the oldest successful human flight technology, dating back to the Montgolfier brothers in France in 1783. A hot air balloon uses a single layered, fabric gas bag (lifting envelope), with an opening at the bottom called the throat.
Attached to the envelope is a basket for carrying the passengers. Mounted above the basket is an "air heater" which injects a flame into the envelope, heating the air within. Raising the air temperature inside the envelope makes it lighter than the surrounding air.
I was wondering why the balloons take off is at 6 AM or 6 PM, the answer is that the lift of the balloon is determined by the temperature difference between the inside and outside air. On a hot day, the balloon cannot be loaded as much as on a cool day, because the temperature required for launch will exceed the maximum sustainable for nylon. Most hot air balloon launches are made during the cooler hours of the day, at dawn or two/three hours before sunset.
A gasoline powered fan is used to blow cold (outside) air into the envelope. The cold air partially inflates the balloon to establish its basic shape before the burner flame is aimed into the throat heating the air inside.
The top of the balloon has a flap of fabric that can be pulled open to release hot air for descent. A crew member stationed opposite the throat, holds a rope tied to the apex of the balloon. The "crown-man" acts as a dead weight in order to slow the envelope's rise so that the envelope can achieve maximum inflation before standing erect.
When the pilot is ready for launch, more heat is directed into the envelope and the balloon lifts off gradually.
In the United States, hot air balloon pilots must have an FAA license. A new commercial-made hot air balloon will cost $20,000 to $30,000.
The balloons fly at dawn or at sunset when the air is cooler.
The text is based on the article Hot air balloon from Wikipedia
Ben Stiller's Balloon Ride - David Letterman, 2014: Ben Stiller recounts how his family took a balloon ride that was anything but enjoyable.
2004 Heinen Blossom Time Balloon Festival in Chagrin Falls, Ohio
2004 Coshocton Hot Air Balloon Festival from Coshocton, Ohio
Ravenna Balloon A-Fair in September
Flag City Balloon Fest in Findlay, Ohio in August
Grove City Balloon Festival
Albuquerque, New Mexico - City is afloat with excitement - USA Today 9/05
Balloon fire. CNN, 08/2005.