RobotWars101

Hi Guys,

I'm building a model zeppelin for my college project. I know where to get all the parts for it apart from one important bit. The material to make the balloon (or envelope as i keep finding it refered to) Without it I will just have a frame and all the helium will escape

I keep finding references to Mylar (BoPET is it's technical name) as the most common material to make it (it's the same stuff shiny party balloons are made of), but i cannnot find a UK supplier anywhere, and i need the material soon.

Does anyone know where i can get some or know of any other materials that will do the job just as well?

Links to what i'm looking for
http://en.wikipedia.org/wiki/BoPET
http://www.rcgroups.com/forums/showthread.php?t=368026

Any help would be great

Thanks

Problem with helium is it's such a small molecule it's difficult to stop it escaping
Mylar really is the stuff to use, but unfortunately I have no idea where to obtain it. Only solution I can offer is to buy some (un-inflated) party balloons and cut & stick to form what you need.

I suppose aluminium foil might keep the helium in, but could be a bit heavy. The advantage of Mylar is that it can be made in very thin sheets, therefore it's very low weight.

Mylar film is available commercially, but it may be difficult to find a "hobby" supplier. Might be worth approaching a commercial stockist to see if you can blag enough for your project - worth an ask...
Try: http://www.katco.eu/mandm.htm perhaps?

BTW "balloon gas" actually contains very little helium, just enough to make a balloon lighter than air. Helium is rather expensive stuff in any decent concentration.

I have actually just recently been using mylar in a university geological mapping exercise - with that in mind, would a specialist stationer's carry sheets of it?

BeligerAnt wrote:Only solution I can offer is to buy some (un-inflated) party balloons and cut & stick to form what you need.

erm.. my zeppelin is about 2m long by 1m wide, i need alot. Perhaps not that method . I am going to try some local model shops, and phone up some balloon manufacturers see if i can get some. In the mean time i bought a metalized survival blanket. It says on the box "strong metalised polyester" which i think is basically what i'm looking for, so i will be experimenting with that.

Thanks anyway for the advise everyone.

Depending on how long you need it to remain buoyant for, ordinary polythene (bin liners?) might work. The metallised blanket is also worth a try, sounds like it might work.
Good luck!

Aren't crisp packets foil coated plastic aka near enough to mylar?

Get eating.

Me again, new problem.

I'm using a deltang board but i want to check that i won't overload it with the 6V battery i'm using. I've attatched the proposed circuit diagram. The speaker at the top is a Pringles speaker i'm using.

Do you think this will work? (i hope so as i have to submit my project next tuesday)

thanks for any advice

The only problem might be if your "6V" battery gives more than 6V. The Deltang is unlikely to cope very well with more than 6V. If you are using 4xAA alkaline cells then you will probably be OK, but a 6V lead-acid battery is actually around 6.8V when fully charged.

I've added a voltage regulator into the circuit so the main board does not overload. Voltage going in was indeed 6.8V but now it is 5.9V max.

the rest of the circuit is still running on "6V".

I will begin programming it tomorrow, and then the final assembly of the whole project .