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VipertheSniper · 11-26-10, 05:13 AM

I don't exactly get what you mean with the taper, but I'd like to go for the 2 hour burn.

lets say I'd build balloons with a volume of around 7 liters how hot would the air need to be to get that of the ground? I'm guessing very hot, as I've read this on wikipedia:

"For typical atmospheric conditions (20 °C, 68 °F), a hot air balloon heated to (99 °C, 210 °F) requires about 3.91 m³ of envelope volume to lift 1 kilogram (62.5 ft³/lb)."

Which would mean (assuming I understand this right) if the temperature were only 99° in the balloon, I'd need 195 liters of air to get 50 grams off the ground. The temps outside will be much lower of course but still, I think that my idea might not be feasible at all.

Well I read some more, and those kongming lanterns are pretty big, I didn't want to build a lantern, or rather several lanterns that big.

Project canceled

11-26-10, 05:13 AM	#5
VipertheSniper Ace of the Deep Join Date: Sep 2002 Location: Austria Posts: 1,070 Downloads: 0 Uploads: 0	I don't exactly get what you mean with the taper, but I'd like to go for the 2 hour burn. lets say I'd build balloons with a volume of around 7 liters how hot would the air need to be to get that of the ground? I'm guessing very hot, as I've read this on wikipedia: "For typical atmospheric conditions (20 °C, 68 °F), a hot air balloon heated to (99 °C, 210 °F) requires about 3.91 m³ of envelope volume to lift 1 kilogram (62.5 ft³/lb)." Which would mean (assuming I understand this right) if the temperature were only 99° in the balloon, I'd need 195 liters of air to get 50 grams off the ground. The temps outside will be much lower of course but still, I think that my idea might not be feasible at all. Well I read some more, and those kongming lanterns are pretty big, I didn't want to build a lantern, or rather several lanterns that big. Project canceled Last edited by VipertheSniper; 11-26-10 at 05:30 AM.