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Introduction of solar hot air balloon

principe d'archimèdeA solar hot air balloon takes advantage of the fact that solar radiation provides about 1000 Watts per square meter. A balloon made of black plastic film and inflated with dry air absorbs enough solar energy to raise the temperature of the air on the inside ; this reduce the air density significantly.

This hot air bubble is lighter than the ambient air. The balloon rises.

Mass of 1 cubic meter of ambient air at 15°C : 1,225 kg.
Mass of 1 cubic meter of air at 35°C : 1,145 kg.
The climbing aerostatics force or lift is therefore 80 grams per m3.





ballon solaire en polyéthylèneA solar hot air balloon for human flight can be piloted vertically by using a valve at the top of the balloon : the solar balloon is oversized compared to it's load. To fly at a desired altitude (level flight), the valve is opened slightly. To ascend, the pilot closes the valve completely. To descend, he opens more the valve.
It is possible :





Animated sequence 110K : How the solar balloon works ?


Video sequence Quick Time


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Solar Balloon - Ignacio Espila Navarro :


Solar Balloons - Alejandro URIBE - BIMANA :


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