h a l f b a k e r yNaturally, seismology provides the answer.
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Conventional parachutes are heavy and bulky partly because they are designed for multiple re-uses.
BorgCo are developing a single use disposable paper parachute. The enclosure is a cardboard box. The Drogue and main chutes are made of specially treated paper. The shroud lines are thin cord which will
stretch slightly on use (thus precluding re-use) but will be strong enough to support the wearer.
Intended for emergencies only. Purchaser must have proof that they have undergone conventional parachute training.
Still in development - testers required. Training given, no previous experience necessary.
Oh the humanity!
http://image.minyan...e/ParachuteBurn.jpg
[2 fries shy of a happy meal, May 08 2010]
Bullet proof paper
http://4entrepreneur.net/?p=1166
[2 fries shy of a happy meal, May 08 2010]
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why would a purchaser require training but not a tester? [8th] up to his usual tricks. |
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Conventional parachutes are actually quite light and compact
- the chute itself will pack into something the size of typical
handbag (though this is not often done for logistical
reasons). If you can develop a paper which is stronger and
also more rip-proof than the ripstop nylon which is used for
chutes, yet is significantly thinner or lighter, I would be
really rather surprised. |
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Could I suggest that you have never, in fact, used a
parachute? |
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He has certainly never, in fact, used one of his parachutes. |
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Put it down to "high staff turnover" ... |
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// you have never, in fact, used a parachute? // |
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This is true. While we are thoroughly familar with the "pilot parachute" (which resembles a thin rucksack), we have never had occasion to deploy it, or any other chute for that matter. |
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We consider leaving a perfectly serviceable aircraft at any point other than when it is on the ground and stopped to be foolish in the extreme. |
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We have observed parachute- related foolishn ess in others, recklessly flinging themselves from aircraft, and have subsequently conversed with the survivors. Apparently they do it for "the thrill". |
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The product is intended for sale via vending machines in airport departure lounges. |
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[baconbrain], you are correct. On the plus side, we can reveal that during the testing phase, the prototypes have performed perfectly consistently. When we see them start to perform inconsitantly with previous trials, then we might me more inclined to try one. |
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// the chute itself will pack into something the size of typical handbag //
..but this is not done for reasons of slow deployment, when it gets lost under the packs of tissues, mints, lipsticks, old airline tickets... |
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I like the idea of someone dropping from the sky
effortlessly in a mess of tattered old newspapers. A 5
dollar parachute could make a new form of travel as
bomber planes carpet cities dropping souls off to
hell. This idea isn't exactly that, but I think this idea
is basically a cheap parachute so, +. |
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If I find myself hurtling gracefully toward the ground at
indisputably terminal velocity, I personally would be
comforted to know that there is more than 5 dollars' worth of
thing between me and a very abrupt deceleration. |
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Purchase price refundable if not completely satisfied.* |
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(*Void where prohibited. Claims must be made in person. BorgCo's liability is limited to the purchase price of the item. No consequential loss, damage, or injury claims will be entertained. Purchaser must return item and original packaging for inspection). |
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I think I see a way to reassemble the pieces of this idea
into something that makes sense. What's wanted is a
parachute that's much cheaper than the ordinary one, with
the savings realized partly through the use of cheaper
materials, resulting in decreased reliability and/or
effectiveness. |
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These would stand in the same relation to ordinary
parachutes as do the oxygen masks that drop from the
ceiling in commercial airliners to the "real" ones used by
pilots (or even hospitals). |
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As in that case the low-cost / low-quality would be
justified by the combination of two factors
1) they'd be very rarely used, and
2) even very low (say, 20%) effectiveness would be great,
'cause the alternative is 100% mortality or serious injury. |
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... Although I think [po]'s right & this is just a scheme to
get people to jump out of airplanes with bits of string &
newspaper tied to their backs. |
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Do you really thing that we are so mean-spirited, exploitative and malevolent ? |
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But you're right. Since the use of this device is "non-elective" there is actually an acceptable failure rate, unlike normal parachutes which are expected to have five-nines reliability. |
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Be assured that our researchers and our few remaining testers are working quite hard to bring the prototype units up to the 20% level you have suggested. |
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I just thought of another line for "Monty Python and the Holy Grail: |
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<French accent>
I don't wanna talk to you no more, you empty headed animal food trough wiper! I piss on your parachute and throw you from the parapet! You mother was a hamster and your father smelt of elderberries! |
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//no previous experience necessary//
...and no future experience guaranteed. |
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I like the idea of a McGyvered parachute made from a worn-out pair of nylons and the sunday paper. |
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//We consider leaving a perfectly serviceable aircraft at any point other than when it is on the ground and stopped to be foolish in the extreme.// |
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Would you consider BASE jumping from an airplane safely parked in a location suitable for that sport? |
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Clearly he has never encountered an in-flight snake infestation. |
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/worn-out pair of nylons/ |
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Even better - a perfectly good pair from the actress our hero is rescuing, and a complicated instruction manual instead of the newspaper. |
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Just have to hope the instruction manual isn't on CDROM ... |
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//The product is intended for sale via vending machines in airport departure lounges. // |
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There's your bun - right there. |
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[8th] the hero prints the manual out using his laptop and portable printer, obviously. |
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It occurred to me that a heroine could use her own hosiery (as she just came from a fancy party) and that such a chute would have a better chance of saving 1 than 2. |
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This idea is now partially Baked at 1/4 scale, using a Tyvek
canopy and polypropylene shroud lines in a waxed Kraft paper
backpack; the harness is made from polypropylene webbing. |
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The cost of a full scale version would be less than USD $100. |
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A scale of 1/4 was selected as an immature human of 640mm
stature is relatively easy to physically overpower and attach to
the unit, and easier to persuade that this is a Fun Game. |
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Tyvek is made from High density polyethylene
fibers. It seems to me that you could get more
strength per pound (and volume) using plain HDPE
like the stuff used for grocery bags. Tyvek is of
course stronger than your typical grocery bag, but
it is also nearly 10 times thicker. (0.15mm vs.
0.017mm). Tyvek is not stretchy. HDPE bags can
stretch significantly before breaking. The
manufacturing process would need to make the
parachutes from continuous material or figure out
a more effective bonding method since the plastic
bags do seem to have a disturbing tendency to
break at the seams. It seems like it might work to
make the shroud lines and canopy from a
continuous sheet of HDPE for a reliable
connection. |
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I don't know what is required for the canopy to
inflate reliably, but based on my ability to open
new bags at the grocery store, that would
definitely need to be addressed. |
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When stretched in one direction HDPE seems to
get narrower in the other direction. Maybe this
principle could be used to make a cheap one-size
fits all harness. The user could put on what seems
like a loose fitting coveralls (with VERY low crotch
and closed foot holes). When the canopy inflates,
the suit stretches lengthwise and shrinks in
diameter, uniformly distributing the force
comfortably distributing the force over gripping
the user over their entire body. Be sure to
remove all sharp object like belt buckles before
use. |
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Producing continuous HDPE sheets in parachute like
dimensions would be relatively simple. Doing it with molded
in lines for extra strength (which could also be melted
through and provide anchor points for the harness lines)
would be relatively simple as well, as long as those lines are
in one axis. |
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I would probably buy several of these, on the theory
that each deployment might slow me somewhat
before failing. Plus I would have something to do;
screaming might get tiresome after the first few
thousand feet. |
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I have jumped out of planes about 500 times,
invariably wearing a parachute. You really, really
really want a material that has the right porosity, the
right strength and above all rip-stop properties.
HDPE (or any continuous film of material) is
fantastically ill-suited to making a parachute. |
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//Tyvek is made from High density polyethylene
fibers. It seems to me that you could get more
strength per pound (and volume) using plain HDPE//
You see, that's just wrong. The strength of Tyvek
comes from the fact that it's a woven material, which
means that rips can't easily propagate. At the tip of
a rip, fibres can shift and shrug so as to dissipate the
stress concentration over a large area. Continuous
HDPE, on the other hand, has no such option and the
stress concentration propagates easily. If you want
proof, go and throw a half-brick at a sheet of
fibreglass and then at a sheet of solid glass (or, for
that matter, solid fibreglass resin). |
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You can buy ripstop nylon (for general use; but in
reality good enough to make a chute from) for about
$1-2 per square metre. You can make a landable
chute with about 40 square metres of fabric. You
could probably make a survivable chute with 20
square metres of fabric (people have actually landed
chutes with a wing area of 3.5 square metres,
involving about 12 square metres of fabric altogether,
but there's a knack to it). |
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So, $40 buys you enough proper material to land
under. |
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