Stop Sticks

[Jacks Complete]

We have had topics on caltropes, carpets with nails in them, and even ultra-tough fibre nets that destroy tyres, but we haven't had one on the "StopStick".

http://www.bonowi.com/prod/ng_EN_STOP_ug_BARRAC.htm is an example.

The Barracuda and other "stop sticks" are a neat idea, and could be improvised really really quickly and easily, and actually be better than the commercial one!

First, we get some steel tube and cut it at the right angle to be an effective penetrator. Do both ends. That site tells us that a 2" tube will defeat even anti-puncture tyres without trouble, so that gives us a good guide. I'd think that even a 1" hole would be plenty!

The comercial design is fitted with two rubber circles and a weight, so that it lands and automatically rolls to the right way up, spikes exposed. However, this means that the operator is obviously carrying a stopstick! They might cut themselves, too. We can do better.

Take a triangular length of foam (Toblerone shape), and into it insert the cut bits of tube. Rotate them such that the first one points from one face to the 2nd, the next from the 2nd to the 3rd, and so on. Stagger them down the length, no more than 1/3rd of a tyre width apart. Now you are good to go. It looks like a foam triangle. Hit someone with it, and you'll do some damage, though!

If you want fast effect, chuck it under a car tyre. Any way up will do. The core will be punched out of the tyre with rapid results on any hard surface. The foam should also drag up and into the wheel arch, which will make driving even harder.

If you want to do the same on soft ground, and/or have a faster effect (about 1 tyre rotation to flat) you want to use a flat board with a few of these in it (obviously cut only at one end.) If you want to conceal it, you can put the foam on top of the spikes, and it will ensure that it remains unheaded (paint it grey or like wood or something) These will actually be sure to core the tyre, leaving a 2" hole for the air to leave through. No tyre sealant will stop that! You would probably also find that the board will smack the underside of the car too.

[Sausagemit]

Good idea!!

But,
The key elements of Michelin's PAX system are special wheels with unique tire bead locks and a solid insert that can fully support its share of the vehicle's weight and let it continue rolling even without any tire pressure.

Run-flat tires may allow the assailant/target to get to safety because they will support the weight of the car for 40-60 miles with zero air pressure and a golf ball sized hole in the sidewall.

I think we can do one better and figure out a way to completely destroy a tire with an improvised stop stick.

Maybe some sort of cheap cast incendiary device inside the puncture tube with a with a wood cap at the end that would ignite once the car rolled over it. And mount it in such a way so that the puncture tube will stay with the tire.

Tire rubber burns pretty well once it hits ignition temp.

As for the ignition, I'm thinking a layer of KMnO4 and a water balloon filled with sucrose, duct taped off then hot glued with a nail in the hot glue pointing at the balloon. But alas, I have never experimented with KMnO4 and sucrose so I wouldn’t know if this would work as it is way more sucrose than is necessary. I'm sure someone else can come up with a better way too.

[JakeGallows]

The Bonowi company also appears to not just to have 2 inch quills but coat them with Teflon as well...

[Jacks Complete]

The teflon is just to ease entry and exit, it's not essential by any means. In fact, if you are sure you really, really want to stop them, having the board nailed to the car tyre is probably more effective.

Screws. That might be the answer. Use screws, which would grip the tyre hard, and not pull out. The board would be solidly attached, and hit the underside of the car. Either this would break the board and leave a solid lump which would seriously limit forward speed due to unbalanced tyres which are no longer round, or the board would break something under the car, stopping it.

Tyres have a lot of forced air, so they would probably stay lit, but I don't know. I imagine any super-advanced run-flat would be made of a fully synthetic non-flamable rubber?

If the screws were wired together with strong (steel?) wire and the board was designed to fragment into smaller chunks, you might well get a good tangling effect. Shredding the tyres in a non-explosive manner is far preferable.

[the_twitchy1]

I'm not sure if it would work, but how about over-pressurizing the tires? I know that the average tire is rated for 40 psi, and will 'blow loose' somewhere around 100 psi, so if you can get the pressure of the tire up to that kind of pressure, rather than depressurizing it, you could have some nasty effects... and the runflats won't be effective at all as they are designed to run low, not high.

The only problem is that I'm not sure how you could overpressurize the tires in that type of way. A pucnture & stay mechanism would be needed obviously to do it, but any tank that could do this would be too big. Hmm...

Anyway, it's a thought. I think that the unbalancing effect with the screws would probably be your cheapest, most reliable, and most cost-effective solution. A few boards wired together in a cross formation, so that some of them would slam up into the sidewalls would probably increase the damage potential, too, thereby causing more pressure loss and possibly ripping the tire to shreds.

[Jacks Complete]

Nice idea. If you had a bit of time to set a trap, dig a trench and put the board over it so that it drops away when they drive over the "speed bump". It will drop the car downwards into the slit trench and stall it, plus the board will be hammered home really well. Once they are stopped with a big board hammered in place across both wheels they probably won't start up again.

As for the overpressure idea, I'm not sure. Think how long a tyre pump takes! Perhaps with a butane cylinder it would work fast and hard? And if it failed, the tyres are full of flamable gas, which might help you.

[the_twitchy1]

I love that! Just so I understand, I've attached a few rough sketches... Is this what you mean? It's a classic one-way trap, too. because the trap will just slap the bottom of your car before resetting itself if you go over it the untrapped way, but hammer those boards home if you go over it the 'trapped' direction...

The only way to get the pressure high enough to blow the tires would be an explosive presurization. No pumping, just have a superpresurized tank that can blow the required amount of air into the tires to put them at exploding pressure. The problem with this is twofold; one, you need to get a lot of air into the tires to do this, which means that a small tank holding that much air would have to be at a very large pressure (especially considering that when it's connected to the tire, blowing air, it's part of the loop and needs to be at tire-bursting pressure, too), and getting the container that holds the pressurized air to release it all at once (or at least fast enough to do what you want). To be honest, I don't think it's possible. The physics of the situation kinda make it, well, hard. But it's an interesting thought, anyway.

BTW, if you really want to be nasty, the trap listed for cars can easily be scaled up to human-catching. Just dig a 10' trench and cover it with a heavy slab instead of a board (or even use boards, but make them sturdy.) Counterbalance the board so that when the person walks over it, the whole rig tips them into the trench, but when their weight is no longer on the slab it bounces back up to the top of the trench. The people inside can't get out because the slab is too high up to grab and to heavy to move anyway. if they can get a hold of it, they can drag it down, but only on top of themselves. I know, it's big, useless, and esoteric... but it's really just a really overdeveloped pit trap at that point.

[Sausagemit]

Tyres have a lot of forced air, so they would probably stay lit, but I don't know. I imagine any super-advanced run-flat would be made of a fully synthetic non-flamable rubber?

They are usually made out of silica compound rubber, which I think acctually melts and burns easier than regular tire rubber. I've seen racing slicks made out of silica compound rubber ignite just from driving on them.

Pretty much all the BMW (the ///M models are the exception) models from '02 till now have been equiped with Michelin's PAX system. They are currently the most widely used run-flat tire on the market. And if I recall corectly, use silica compound rubber.

I might have to shave a little bit off of one of my Dunlop SP Sports and see how easy it ignites. Just to make shure that I'm correct in saying what I just said.

[Skean Dhu]

The only way to get the pressure high enough to blow the tires would be an explosive presurization. No pumping, just have a superpresurized tank that can blow the required amount of air into the tires to put them at exploding pressure. The problem with this is twofold; one, you need to get a lot of air into the tires to do this, which means that a small tank holding that much air would have to be at a very large pressure

A simpler solution would be to use actual explosives, Sodium azide(used in airbags) when detonated converts into a whole lot of nitrogen in a very short amount of time.

So theoretically all one would need is a container to hold the blast(say an airbag canister) a puncture tube to deliver the gas and a means to detonate the sodium azide when the tube is in the tire. All one would need to do is rig it similar to the VC bullet mine( dig a hole, place a board with a nail in the bottom, place a tube over the nail, set a bullet on the point of the nail), use the cars weight to set off the explosion.

http://www.chemistry.wustl.edu/~edudev/LabTutorials/Airbags/airbags.html
According to the above site you have around 60L of nitrogen to cram into the tire in a matter of 40 milliseconds. If one were to use a standard airbag canister as the gas generator.
That should put a little bit of stress on even the best made tires.

[FUTI]

I heard once about assasination method which involves replacing a portion of air in a car tyre with propane/butane gas. Then the victim goes to the highway and when the tyre go hot enough it blows. At the speed the car normaly goes at highway driver has little chance to survive the crash and I really want to see how would police CSI that...maybe by mercaptane trace if they manage to find it (hardly) or partial rubber depolimerisation by the mercaptane present in gas (unlikely). I know this is OT but over-pressurisation story digg-up this from my mind.

[akinrog]

I heard once about assasination method which involves replacing a portion of air in a car tyre with propane/butane gas. Then the victim goes to the highway and when the tyre go hot enough it blows. At the speed the car normaly goes at highway driver has little chance to survive the crash and I really want to see how would police CSI that...maybe by mercaptane trace if they manage to find it (hardly) or partial rubber depolimerisation by the mercaptane present in gas (unlikely). I know this is OT but over-pressurisation story digg-up this from my mind.

If the above scheme is feasable (which I don't know for sure), one can use propellant butane used in deodorant sprays, instead of regular LPG gas. I don't know how it's in other countries but in my country it's mandatory to use propellant grade butane/propane in pressurized sprays since other propellant gases deplete the ozone layer.

Since this butane/propane gas used in vicinity of humans, they do not contain mercaptans. Think for a moment you have a deodorant which stinks like a skunk :D.

[FUTI]

Yes and I manage to find a cigaret lighter refill LPG or propan/butane container that doesn't contain mercaptane (now that should be illegal in my country but... if it isn't pressed under the nose of the law, the eyes of the law won't see it ;)).

I doubt that it is reliable to ignite that mixture when the tyre heat up, but it is plausible and smart assasin can make explosive mixture (you know the volume of the tyre, pressure of air, add LPG to a certain point where the pressure of the mixture corespond to a perfect explosive composition (which should be close to a tyre blow-out limit)). There is a legend that some old local politician (in my neighborhood) is "removed" that way.

[nbk2000]

You could take a piece of encapsulated sodium or potassium, coat it with superglue, slip it into the tire through the stem (using a stem-core removal tool), let it set, then rotate the tire 180 degrees and add a couple cups of water.

If you then inflated the tire with an ideal gas/air ratio, when the car was driven, the water would contact the sodium metal capsule, dissolving the coating, react with the water, igniting the gas, and BOOM!. :)

But how fucking complicated is that compared to putting a bomb under the car?

[ShadowMyGeekSpace]

There's one problem with that, have you ever taken a fully inflated tire, deflated it quickly, and then taken it off the rim? Water condenses on the inside of tires when they're inflated and put under pressure.

[nbk2000]

Hence the encapsulation.

It'll take some time to dissolve, and require immersion in liquid water, not just dew, to dissolve enough to expose the sodium.

Or screw a squid into the the tire stem, with a centrifugal switch that'll close the circuit once the vehicle gets up to freeway speed. :)

[teshilo]

I heard once about assasination method which involves replacing a portion of air in a car tyre with propane/butane gas. Then the victim goes to the highway and when the tyre go hot enough it blows. At the speed the car normaly goes at highway driver has little chance to survive the crash and I really want to see how would police CSI that...maybe by mercaptane trace if they manage to find it (hardly) or partial rubber depolimerisation by the mercaptane present in gas (unlikely). I know this is OT but over-pressurisation story digg-up this from my mind.
Propane can be replaced on hydrogen. After explosion find only traces of water.

[Jacks Complete]

Hydrogen is the best one. It would be utterly impossible to find anything from any investigation, unless there was, perhaps, a little hydrogen embrittlement of the steel rims, or a video of the tyre going bang. Plus the great thing about H2 is that it burns/bangs at almost any mixture level, unlike most fuel gases which are actually quite fussy.

[teshilo]

Also as delayed igniter can be used 30% (or more)hydrogen peroxide.

[FUTI]

I think that most reliable idea in this thread (that uses over-pressurisation) is combination of airbag gas generator and centrifugal switch NBK proposed (that is a good one I think you could make it close that circuit only when car reach certain speed)...but it is easy to CSI that from the remains it left behind.

Hydrogen is cool idea from reliability of making a right mixture issue, but it is harder to find a bottle of that gas isn't it? Sodium generation of hydrogen "in-situ" ;) is easy to make (but require good "hands" with a head who knows what they are doing) and also leave good trail to CSI team (higher then average sodium level and maybe splinters of unreacted sodium).

Teshilo I'm curious about your hydrogen peroxide delayed igniter idea...would you please explain with little more details.

I appologise for stealing the thread, please move those posts elsewhere where they are more on the topic or make a new thread.

[teshilo]

Use high concentrated H2O2 mixed with organic substance as delayed igniter for arson discussed in "Silent Death" by Uncle Fester .As these placed in to tire ?May be used pump with hollow needle.

[Jacks Complete]

I doubt you would need anything more than just the peroxide inside the tyre at that concentration (30%). The heat and agitation would easily cause decomposition within a short distance at any speed. It might even cause the rubber to start burning chemically without any ignitor or additional stuff. That way, CSI would only find water and burned rubber.

Anyone want to grab an old tyre and run a test?

[nbk2000]

Even if it didn't ignite, the decomposing peroxide could cause the tire to overpressurize and rupture, though whether or not it would do this while the car is in motion (and not just parked) would have to be tested.

[teshilo]

As about use of corrosive chemical for stopping car?

[Jacks Complete]

I don't think many non-explosives would act fast enough. At least not the sort of things that would agree to being on the road for a while.

[FUTI]

This is stupid maybe but benzoyl-peroxide should be decomposing at 80 degrees Celsius which should make it good peroxide candidate for NBK's and teshilo's idea. That way you done all you can to use peroxide which will be inert until certain temperature of tyre is obtained on road when overpressure blows the tyre.

It can still be found by CSI unless someone mistake those traces of benzene as contamination from solvents used for tyre mould cleaning or even their own procedure for taking tyre "fingerprint" (there is some method where they take some hydrocarbon mixture like ligroin and soak the tyre surface before they roll the tyre over clean white sheat of paper).

[kelb]

I dunno about a "chemical" stop stick. But if I was that damn desperate to get away from the cops and saw one standing by the road about to sling a stop stick in front of me, well lets just saw he better be quick or his ass and my hood would get in the same place.

That being said for the most part there is still a decent amount of steel in the bodies of even more modern cars. Seems like 4-5 hard drive magnets stuck to 1/2 to 1 pound of C4 could be tossed onto the car and stick. Then by remote detonation you could disable the car easily. Think of it as a modern and much less dirty sticky bomb.

[teshilo]

Nazi in WW2 used similar desigh cone-shaped SC magnetic limpet grenades-mines.For protect tanks used special coating on bottom.

[Jacks Complete]

Remote detonation? Why not a 5 second fuse? Cheaper and more use, as well as more reliable. If you leave it more than 30 seconds they will have stopped and either removed it or caught you, and you simply have the fuse light on contact.

You could hide a device like this in a water filled pothole, so it automatically jumps and sticks to the first car to hit the pothole, then 5 seconds later goes bang.

[Sausagemit]

Stop sticks are going to be completely obsolete in a couple of years if Michelin's Tweel hits the market anytime soon.

http://i121.photobucket.com/albums/o240/eurodfp/33.jpg
http://i121.photobucket.com/albums/o240/eurodfp/22.jpg

Oh well, we will just have to keep up on ways to stop cars quickly with Tweels :D

+++++++++

Originally mentioned here (http://www.roguesci.org/theforum/showthread.php?p=85403#post85403). NBK

[festergrump]

Ever see what happens to a bicycle when you ram a broomstick in the front spokes whilst it's travelling?

[nbk2000]

Try jamming a broomstick into a tweel going at 50MPH.

The spacing is much closer together on the tweel's supports than the spokes of a tire, and traveling at a much faster rotational velocity than you'd ever get with a bicycle.

Of course, there is money to be made by the person who comes up with effective ways to deal with the proliferating numbers of run-flats and future tweels. :)

[Sausagemit]

Sorry about that NBK. I didn't realize you posted a very similar post about the tweel in another topic on the same day almost exactly 12 hours before me. :o It is a pretty strange coincidence though. And just so you don't think I'm plagiarizing you and trying too pass it off like nothing happened, I first heard about the tweel here (http://forums.thecarlounge.net/zerothread?id=1759169) a little less than a year ago and a recent repost (http://forums.thecarlounge.net/zerothread?id=2998343) on a subsidiary forum brought it too my attention again and I thought the roguesci community might like to know about it. Those links probabbly did little to convince you but all I can say is evil minds must think alike. :D

Festergrump, a bike with a person on it weighs at most 5%-10% of what a car weighs. You would have to either get something very stout and thus very heavy and hard to handle or something very sharp if you plan on either seperating the spokes or stopping the car completely by shoving something in the tweel.

Preliminary tests by Michelin show that the Tweel can run over explosives and keep on rolling even if some of the spokes are broken and some tread ripped off. It also directs the blast energy of land mines and other explosives outward rather than up and into the vehicle like traditional tyres.

http://www.tyresite.com/tyrearticle.asp?page=13

And it looks like most small yield explosives are out of the question.

[Jacks Complete]

Good stuff. Of course, they are illegal in the UK, like any tyre that has a zero air pressure!

Liquid nitrogen would deal with these, but timing would be an issue. As regards "keep on rolling even if some of the spokes are broken and some tread ripped off", that's going to be rather like your current tyres, which will merrily drive 5 miles without issue when flat. They won't ever work again, but it is worth knowing that as long as you don't overheat the engine and keep it below 15mph, you can drive on tarmac on a flat without much more than increased road noise. With spokes and chunks missing from a tweel, you are going to have much the same balance and speed issues.

[nbk2000]

I bet they say the 0-PSI tire ban is for 'safety', right? Not so that they can kill your car tires with stopsticks and immobilize you, eh? ;)

[Jacks Complete]

I don't think they had run-flats back then. It's just one of those badly worded laws, we have so many of them. Time and mankind has moved on a long way since Mr. Dunlop first got a law passed to protect his market.

[FullMetalJacket]

I'm thinking that an injection of pirhana fluid into the tire would cause it some grief. Spontaneous ignition, anyone? Mind you, it would leave residue, so it's not as good as some of the other options mentioend.

[Jacks Complete]

http://www.military.com/NewsContent/0,13319,121457,00.html?ESRC=dod-bz.nl

Interesting article on just how far behind the curve the US military are in places. Like Humvees not having run-flat tyres! I mean, how retarded is that? (Apparently it uses an air pump to reinnflate the tyre if it goes down)

The article also shows how dull the thinking is about this. The military guys at the top are saying "We are years away from having a passenger car application," Mann said. "We do have a very early prototype for a passenger car. When you get it up to a high speed, 50 or 60 mph, there is noticeable noise. We need to solve the noise issue."But who cares about running noise at 60 on a Humvee, when the other option is death by RPG?

Pergantis of the Army Research Center said airless tires must provide comfort, no vibrations and little noise, in part because of the sophisticated electronics used in military vehicles. Which is odd, because I would have thought that the tyre should provide mobility first, and everything else second. The burned out humvee is not a better vehicle than the one with a slightly higher level of road noise.

So, apparently stopsticks will kill a humvee.

[nbk2000]

I'd think that since most army units aren't involved in combat, it's better for them to use tires, as the constant vibration and noise of tweels (or tracks) is a constant fatigue factor.

But, when your unit rotates into the sandbox, on go the tweels, since they won't go flat from fragments and bullets in the middle of a firefight.

[FullMetalJacket]

So, apparently stopsticks will kill a humvee.

So will half a pound of plastique and a martini glass.

Humvees = Wheeled coffins.