High Pressure Tube Plugs

[pyronaught]

For a thin wall inflated tube, 5 psi might not seem like much pressure but it is significant. Consider the average inflatable has less than one half PSI and the Goodyear Blimps are inflated at .07 PSI. While you can't really see the 3D printed two-piece plugs holding the ends of the 24 ft long tube below, you can see that they hold up to the pressure without leaking and are designed to avoid any 90 degree sheer stress on the film. I spent almost two weeks printing all kinds of plug designs, blowing up tubes and shooting plugs across the room like a cannon when they failed--- but it would have taken MUCH longer to prototype this any other way. Doing it on a lathe would have taken more skill than I have due to the curves and matching tapers involved. This is my first use of a 3D printer to solve a problem and it really worked out great!

tube_plugs.jpg (675.61 KiB) Viewed 13294 times

[jimc]

interesting. so what would someone do with a clear inflatable tube?

[pyronaught]

interesting. so what would someone do with a clear inflatable tube?

The tubes are so rigid even with just a few PSI that they can be used as structural elements. They have been used as inflatable supports in temporary outdoor structures such as tents and shade covers, with the ability to quickly assemble and disassemble with minimal storage space. NASA is even using them for inflatable structures to be deployed in space due to how little space they take in storage and the high strength to weight ratio. I am experimenting with using them as structural elements sewn into the fabric of a new type of hot air blimp I am designing. It's a very ambitious and expensive project I've been working on for years now in the form of scale RC prototypes, so I'll need to get a roll of smaller diameter tubing next to use for the RC model. The one in the picture is the size that would be used for the full sized blimp. A development history of the RC model can be found here: http://www.rcgroups.com/forums/showthread.php?t=1405313

[jimc]

huh, thats very interesting. keep us posted on your progress.

[pyronaught]

The blimp progress will be posted to the build log linked to above. I'm working on an RC flying saucer that will likely be using some 3D printed parts too so I can post that here. It's not a run-of-the-mill quad being passed off as a flying saucer, it legitimately looks and flies like a flying saucer and is about 9ft diameter. Last year I built a large 16' x 8' CNC fabric cutting table to be used for both these projects. That one took three months to pull off since there are no kits or plans available for building CNC fabric cutting tables, and certainly nothing out there on making heat sealers for seam welding. The details on that build is documented here: http://www.cnczone.com/forums/diy-cnc-r ... c-cad.html

[jimc]

hahaha a 9ft flying saucer. your gonna spook some people with that one. all those sightings on the news over the past 20 yearsare probably from you! lmao

[pyronaught]

hahaha a 9ft flying saucer. your gonna spook some people with that one. all those sightings on the news over the past 20 yearsare probably from you! lmao

Well, I haven't got mine working yet but I'm not gonna lie-- freaking people out is a big part of the motivation

Most of those UFOs you see on the news are sky lanterns, and I've sent up my share of those too. They are easy to identify once you know what they look like, but the TV news people take the bait every single time.

[jimc]

haha thats awesome!

[Tim]

freaking people out is a big part of the motivation

You're going to freak out the FAA, too, with that one. But I'm all in favor of it!

[pyronaught]

freaking people out is a big part of the motivation

You're going to freak out the FAA, too, with that one. But I'm all in favor of it!

Currently the RC saucer wouldn't violate any FAA rules, but if they ever rammed through some of those draconian "drone" rules being proposed then it could depending on how they defined "drone," which is a very misused term these days.

The FAA would be a bigger problem for my long term blimp project, since they do not have a type certificate for hot air blimps. Whenever they don't have a classification for something they just lump it into the next closest thing because they are too lazy to make up a new classification. So currently to fly a hot air blimp, you would either need a fixed wing pilots license or a gas blimp license-- neither of which would give you the skills to actually fly a hot air blimp while requiring a bunch of unrelated skills you would not use at all. Hot air blimps are closer to hot air balloons more than anything else, but a specific classification needs to be created for them just like Europe has otherwise the current rules would severely impact the ability to sell hot air blimps to the public.