Building a hot air balloon (sort of)

VipertheSniper · 11-26-10, 03:58 AM

I just had an idea for something which might look awesome, but I don't know if it's possible to pull it off... Building lanterns in different colors that can lift up from the ground.

So I've got a question, which some here might be able to answer: How big would such a lantern have to be to lift itself and maybe some lenght of fishing line off the ground, if the air is only heated by a tealight?

The lantern of course would have to be as light as possible. I don't know how much a tealight weighs but I'm guessing somewhere around 25 grams, so maybe the weight of the lantern with light should be somewhere around 50 grams. How much volume would one lantern need to lift off, repsectivly would a tealight produce enough heat at all?

11-26-10, 04:15 AM

So you want to build some chinese sky lanterns with different coloured papers instead of buying them?

VipertheSniper · 11-26-10, 04:16 AM

Yeah I want to build them myself... feels like more of an accomplishment, than just to buy them.

11-26-10, 04:23 AM

In that case would a taper be better than a tea light to keep down the weight or would you be going for the 2 hour burn?

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, 05:46 AM

Quote:

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

Basicly a taper is a typical candle shaped candle and is not in its own container like a tealight is, so while the heat given off from both with a single wick would be the same one will be at the start heavier and remain heavier throughout but will give off the same heat for much longer as all the fuel is burnt.

VipertheSniper · 11-26-10, 07:05 AM

The translator just gave me the word "Konus" which is just a description for the shape of the candle, so I was a bit confused what you mean exactly.

Yeah a taper would be lighter as there's no metal surronding it. I've done a bit of calculating and it should be feasible to produce some lanterns with enough volume that still have a reasonable size... so I might do this after all. That would be definitely something else to greet the new year around these parts.

Armistead · 11-26-10, 09:29 AM

Are we gonna see you on TV chasing a ballon with a kid in it....remember that guy,.....

11-26-10, 03:58 AM	#1
VipertheSniper Ace of the Deep Join Date: Sep 2002 Location: Austria Posts: 1,070 Downloads: 0 Uploads: 0	Building a hot air balloon (sort of) I just had an idea for something which might look awesome, but I don't know if it's possible to pull it off... Building lanterns in different colors that can lift up from the ground. So I've got a question, which some here might be able to answer: How big would such a lantern have to be to lift itself and maybe some lenght of fishing line off the ground, if the air is only heated by a tealight? The lantern of course would have to be as light as possible. I don't know how much a tealight weighs but I'm guessing somewhere around 25 grams, so maybe the weight of the lantern with light should be somewhere around 50 grams. How much volume would one lantern need to lift off, repsectivly would a tealight produce enough heat at all?

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.

11-26-10, 04:15 AM	#2
Tribesman Stowaway Posts: n/a Downloads: Uploads:	So you want to build some chinese sky lanterns with different coloured papers instead of buying them?

11-26-10, 04:16 AM	#3
VipertheSniper Ace of the Deep Join Date: Sep 2002 Location: Austria Posts: 1,070 Downloads: 0 Uploads: 0	Yeah I want to build them myself... feels like more of an accomplishment, than just to buy them.

11-26-10, 04:23 AM	#4
Tribesman Stowaway Posts: n/a Downloads: Uploads:	In that case would a taper be better than a tea light to keep down the weight or would you be going for the 2 hour burn?

11-26-10, 07:05 AM	#7
VipertheSniper Ace of the Deep Join Date: Sep 2002 Location: Austria Posts: 1,070 Downloads: 0 Uploads: 0	The translator just gave me the word "Konus" which is just a description for the shape of the candle, so I was a bit confused what you mean exactly. Yeah a taper would be lighter as there's no metal surronding it. I've done a bit of calculating and it should be feasible to produce some lanterns with enough volume that still have a reasonable size... so I might do this after all. That would be definitely something else to greet the new year around these parts.

11-26-10, 09:29 AM	#8
Armistead Rear Admiral Join Date: Dec 2008 Location: on the Dan Posts: 10,880 Downloads: 364 Uploads: 0	Are we gonna see you on TV chasing a ballon with a kid in it....remember that guy,.....