diy high altitude balloon project in australia

and legalities... I'd suggest your local model rocket club/associsation would be a good place to start.

Dave.

Go for a tour of a BOM weather station at an airport or country centre where they launch weather balloons / sondes. You'll get some good ideas there. Google Vaisala sondes and see if you can get the specs on weight size etc.

hi, hmmm theres no model rocket/club around here for about 300 plus km`s !!!

mark k

High altitude glider project

dmm

Hi, here are some basic equations to help.

density of air (nitrogen) = 1.18221 kg/m^3 density of helium = 0.178 kg/m^3 balloon lifting capacity = 4/3 * pi * r^3*(density air - density helium)-mass of balloon. where r is the ballon diameter

Also PV=nRT , so as the balloon rises it's diameter will increase, so don't fully fill a balloon.

As the balloon rises the air density decreases, so if there isn't enough initial lift in the ballon it will reach an equilibrium height rather than the balloon limit.

Hope that's a start, recommend a trip to the library for a physics book or two

have a look here too

Good luck

Greg

Troll the web. I remember there is at least one page out there. Not very common in Australia, partly as we have highly controlled airspace.

Caveat; at high altitude, your lifting gas expands greatly, which is why the high altitude weather kit is like it is.

Well, i know someone locally is still at the orange garbage bag hot air ballon stage of developing their own high altitude(?) balloon. They have found that night times are the best time for maximum height(and best local newspaer coverage of "Flying Saucer Scare" {:-).

Hi again, of course you want the ballon to burst at some point so it returns to earth. It's a matter of knowing the burst diameter of the balloon and then working out at what height that will occur.

Density of air as a function of height can be calculated, have a look here

Cheers Greg

When I was 15 I sent up a hot air balloon that was reported in the local paper as a UFO. I used one of those bags the dry cleaners put over your clothes when they've been cleaned.

Oh no,no,no, You want something a bit better controlled then that. you really need gas release at a certain height, with auto parachute deployment, plus emergency release, such as you suddenly discover that your previous payload is making for Antartica.

It is/was a common brussel sprout activity at one stage. The local person is obviously using orange garbage bags.

These are very easy to make, You just make a loop of light wire to hold the bag open and tape bag mouth around it. Support cotton wool ball in middle on two thin wire cross arms. Preheat air with metho stove or similar(do this for longer flight), then when it is lifting, light metho soaked cotton wool ball and let it lift off.

Works great with no crosswinds and on coldish nights.

Bingo!

Hi Mark, Where do you live? I've an interest in doing the same. Sydney's not a great place from a free air-space perspective though :)

Terry

hi, i live in renmark , south australia , " perfect weather one day , beautiful the next ....."

mark k