Tire Inner Tube for a BC bladder?

[dannobee]

Well, at least you're using a truck inner tube, they're thicker and some truck tires are rated over 120 psi. Obviously the tube is contained by the tire, so a stand alone tube won't see that much pressure. But hey, we've probably all taken a balloon underwater to see what happens, and they're pretty thin. I wouldn't try it without my regular BC on-even in a pool.

Just get one of those fisherman models with the waders built in. It'd be more interesting when you boat dive. Never mind the wild looks and snickering from the crowd.

Talk about lift though. You'd have plenty.

 

[m3830431]

Where do find one that fits? Goodyear or Firestone?

 

[Sideband]

In spite of what another poster commented, many people do make their own chutes.
BUT
Obviously it would only be as safe as the competence of the person building it.

I don't want to sidetrack this or start an arguement, but I would like you to quantify "many people". I used to hang out and jump at one of the largest, if not the largest DZ, in the states with several hundred jumps happening on a decent day. I have never met anyone that would even consider making their own canopy. I would guess that it would be a very small fraction of a percent of all skydivers that would consider it. I would not call that "many". Maybe you would though.

Joe

 

[O2BBubbleFree]

Given modern materials, rubber & adhesives technology there is no limit to what a DIY enthusiast can do these days.//snip//
Obviously it would only be as safe as the competence of the person building it.//clip//I don't think the economics would work unless you also have access to a lathe & other workshop tools. By the time you've paid for some decent dump valves, d-rings, velcros, clips and an inflater hose & power etc you'd be near the cost of a reliable BC. Certainly above the cost of a good used BC.//chop//The only advantage would be the satisfaction of knowing that you built it yourself.

I agree. The idea is worth thought, but if you can't make your own inflator, dump valve, overpressure valve, etc. than you won't save any money. You could, maybe, buy a used BC for parts, but then you wouldn't need to build one, would you? Even if you bought one that had a bad bladder, it would probably be easier to fix the bladder than replace it with an inner tube. If you stuffed a tube inside a BC you would have to worry about wrinkles in the tube holding air pockets, and stuff like that.

I've run across several home-built rebreathers that use inner tubes as counterlungs. This one even uses an imaginative, low-budget water trap:

http://www.metacut.com/rebreathers/TP2000/Default.htm

Of course, this is definetly an area where you really want to know what you are doing, since rebreathers are devious devices that can sneak up and kill you in a variety of ways, without bothering to warn you. Not that I'm against rebreathers, I just believe that you have to know a lot to dive one, and a whole lot more to design and test one, and you may die anyway.

 

[O2BBubbleFree]

I have never met anyone that would even consider making their own canopy.
Joe

My quick Google search (I'm bored) turned up one unsuccessful attempt, a DB Cooper wannabe who hyjacked a plane, then jumped out with a homemade 'chute:

"An on-ground witness reported seeing someone parachute out of the Philippine Airlines jet. But the homemade parachute did not remain intact...The body was embedded in the ground with only the hands protruding."

 

[miketsp]

I don't want to sidetrack this or start an arguement, but I would like you to quantify "many people". I used to hang out and jump at one of the largest, if not the largest DZ, in the states with several hundred jumps happening on a decent day. I have never met anyone that would even consider making their own canopy. I would guess that it would be a very small fraction of a percent of all skydivers that would consider it. I would not call that "many". Maybe you would though.

Joe

I would just point out that you cannot take a statistic from a jump zone in the USA, where all sorts of up to date technology & products are available just by writing a check, with what happens in 3rd world countries or those with severe import restrictions.
I remember discussing this subject once with one of the few jumpers I know and he told me that he and his friends would design their own chutes and then they would test (with a weighted dummy) a prototype made from a hot-air balloon envelope before sewing the final design from new material. Apparently hot-air balloon envelopes are a cheap source of ripstop nylon as they have a limited life due to regulations.
World-wide I really have no idea how many people do this.

I don't see what's so complicated. Da Vinci designed his in 1400, Louis Lenormand jumped with a home-made one in 1783 and Andre-Jacques Garnerin dropped from a balloon at a height of 680m, using a canvas hemisphere as a parachute in 1797.

Nowadays the availability of tough lightweight fabrics and lot of literature on parachute aerodynamics have made it relatively easy to make a chute in whatever form you want. Anything from large hemispherical to the small rectangular ones used for display drops, boat towing etc.

 

[el-ninio]

I wouldn't try it without my regular BC on-even in a pool.

This is the right time to mention that a bc is NOT LIFE SUPPORT EQUIPMENT IN A POOL!

As for the original question: You would want a small tire. One from a normal car size tire should give you all the lift you need. The pressuer the tire is rated for is probably irelavent. you will have to build a shell, as rubber is not all that durable to phisical abuse. On the down side, rubber has a tendency to fail catastrofically when if fails, and that's not too hot for a bc. One other issue you will need to consider is what sea water may do to rubber.

you should be able to use the hardware from any old BC for this aplication - at least for the hose essembly. you may need to do some more work to get the overpressuer valve to connect. And if you intend to dive this - make double sure the overpressure valve works!

 

[cnctina]

What a great idea, no more bad service at the local dive store when you need a part for it.

 

[Diver Dennis]

I have over 200 jumps and have never heard of anyone making their own parachutes... Are they still alive?

 

[Diver Dennis]

Sorry to get off topic but used hot air baloon nylon that is no longer good enough for the baloon is probably not good enough to manufacture a canopy from. I admire the determination of a lot of people who try to make their own gear but the amount of time and materials, let alone research, that would go into manufacturing a complicated BC or a parachute is not cost effective or time effective. Unless you are retired and have a whole bunch of money, why would you even think of trying something like this? And if you were retired and had a whole bunch of money you would probably want to spend the money and time actually going diving. I can see it if you wanted to make a prototype for a production model, but to just make a one off? Even if you had a used one and took it appart for a pattern, could you buy fabric for the same cost as a large factory? Would your sewing, assuming you had the proper machines, be strong enough and defect free? There is a difference in understanding the theory behind parachutes and actually manufacturing one. Having owned a business in the needle trade for 25 years I can attest to that. I'm sorry but manufacturing your own design of complicated life dependant equipment is best left to the experts.