h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

I decided I needed a bit of a project to work on, so I'm planning to work out how to launch my own mini hot air balloon. All work and no play and all that

My plan is to design and launch my own balloon from some remote Devon hillside in the next fortnight. My design is quite simple. I've inflated a balloon, covered it in paper mache, and plan to dangle from it a Styrofoam cup containing a tealight candle. The idea is that the candle will provide the hot air, and the paper mache will be light enough to be lifted by the hot air.

There are some potential design flaws; flammability of the mache, weight, possibility of the candle blowing out and so on. I think it's going to be fun to work out, though. The idea of using a tealight is that it will burn for a long time, so a well-designed balloon could fly for quite a long time.

The reason I'm posting here is that I thought it would be fun to see if anyone else had any ideas for getting a hot air balloon to fly. I know some people might be able to tell me that my plan won't work for whatever reason, but I also hoped that maybe one or two of you might have ideas of your own. So I thought I'd challenge the good folk of SEx - can you design a hot air balloon that will fly better than mine?

Here's the rules:

1. You just need to describe how you'd make your hot air balloon in a way that I'll be able to make it here. Make it clear and easy for me. There are some designs on the Internet that involve cutting bits of tissue paper in exact shapes and connecting them in very specific ways, but I don't have the patience for that, so keep it simple if you can.
2. I should be able to assemble your design on a kitchen table using stuff I can find around the house or in a local hardware shop, so nothing technical please.
3. Self-powered balloons would be ideal - one of the tests I'll be subjecting my design to will be length of flight, so if you want me to fill it with hot air from a hairdryer you'd better make sure the heat will stay in it for a while!
4. Avoid plastic bags if you can, because I live by the sea and they tend to choke whales and turtles. Anything heavy that might cause injury if it lands on someone is also out.

If anyone does have a design, I'll film the construction and flights for an Aviator film to accompany a future Post article (or if we're especially good, for the EG) on the subject. I plan to launch any attempts of mine that may work from a field on or near Dartmoor, and I'll do the same for any of your suggestions. Mad ideas along the lines of 'This might not work, but...' are especially welcome - I think it will be fun to experiment.

Over to you

to make your paper mache' use a fire resistant PVA

dont use a styro foam cup as the tea light base gets very hot and might melt through the base of the cup leaving the balloon powerless

construct some sort of metal funnell (cut from a drinks can) to direct the hot air into the mouth of the balloon

thats all that comes off the top of my head at the moment

Get some Borax for fireproofing. Best stuff, without a doubt.

AND, if you mix PVA glue with Borax, you can make Silly Slime.

B

Check whether your personal insurance covers you for damage caused by incendiary missiles

My brother makes hot air balloons Rich. He uses tissue paper, a thin base frame made from wire, and it's elevated using a wodge of cotton wool soaked in turps. The advantage of the tissue paper is that it's light and if you set it off at night you can see it go for miles.

Dad used to make and launch them on Bonfire Night every year and one time we watched as it came down in flames over the Stanlow Oil Refinery on the Mersey Fortunately there was nothing in the News the next morning

I can ask bro for his 'recipe' if you'd like?

Fb

Yes please, FB

Where can you get Borax, then? We've tried Boots and Sainsbury's to no avail.

I don't think papier mache is light enough, unless you make the balloon about 10 feet in diameter. Tissue paper is a good material for hot air balloons, but I don't know how you stop it going on fire.

My brother has a template he uses, which makes sure that the whole thing is perfectly balanced. Of course, a gust of wind creates havoc

Request sent to big brother for his formula

Wow... some people have given this a lot of thought. A quick google for "candle balloon" (I was searching for something I've recently read about very similar balloons being launched as a tradition, but I couldn't remember where or why or exactly how they were made) and I find pages like this.

http://www.overflite.com/rosebud.html

There were several how-to sites and a couple of videos. One of the videos lists a website on how to make solar powered ones as well. No fire risk from those. http://www.solar-balloons.com/

Yes papier mache is rather heavy. The ones I have seen used rice paper. I also helped construct a larger one from thin plastic, I can´t remember if that ever worked.

Borax is often used in detergents and dry cleaning - ask whoever does the hotel laundry where they get theirs. They might even slip you a bit - it's dirt cheap.

B

You can fire proof tissue paper by spraying it with a bi-carbonate of soda solution. When it dries it forms a black carbon deposit when a flame is played on it, that protects the structure of the tissue paper.

Of course you could try these...

http://www.skylanterns.com/skylanterns/index.php?option=com_content&view=article&id=50&Itemid=60

The thing about these that worries me is the fire hazard. The ones run on candles seem a bit safer. A candle flame is unlikely to survive the wind of a fall. Even in the above mentioned skylanterns video I see at least one lantern drop part of its flame and the flame keeps burning as it drops.

I'd also recommend that the balloon material be something that either doesn't burn at all or burns quickly. If it burns quickly then by the time it reaches much altitude at all, if it ignites it will burn completely before landing. Rice paper might work well.

Silk is traditional... I'd steer away from any kind of polyester or other man-made fibres, since they tend to melt and drip very hot drips when they catch fire.

How about some form of origami balloon?

The solar-powered ones all seem to involve blowing up a black balloon or foil bag and waiting for the sun to heat the air inside. Unfortunately, that kind of material is unsuitable because of the danger to sea life...

If you didn't want self-powered, I could get the directions from one of the 6th grade teachers at my school--the first spring I was working there, the whole school turned out to watch his class's balloons. I seem to remember that they were filled over a stove-type thing, though...