Books You Should Read: IGNITION!

Isaac Asimov described the business of rocket fuel research as “playing footsie with liquids from Hell.” If that piques your interest even a little, even if you do nothing else today, read the first few pages of IGNITION! which is available online for free. I bet you won’t want to stop reading.

IGNITION! An Informal History of Liquid Rocket Propellants is about how modern liquid rocket fuel came to be. Written by John D. Clark and published in 1972, the title might at first glance make the book sound terribly dry — it’s not. Liquid rocket fuel made modern rocketry possible. But most of us have no involvement with it at all besides an awareness that it exists, and that makes it easy to take for granted.

Most of us lack any understanding of the fact that its development was the result of a whole lot of hard scientific work, and that work required brilliance (and bravery) and had many frustrating dead ends. It was also an amazingly dangerous business to be in. Isaac Asimov put it this way in the introduction:

“[A]nyone working with rocket fuels is outstandingly mad. I don’t mean garden-variety crazy or a merely raving lunatic. I mean a record-shattering exponent of far-out insanity.

There are, after all, some chemicals that explode shatteringly, some that flame ravenously, some that corrode hellishly, some that poison sneakily, and some that stink stenchily. As far as I know, though, only liquid rocket fuels have all these delightful properties combined into one delectable whole.”

At the time that the book was written and published, most of the work on liquid rocket fuels had been done in the 40’s, 50’s, and first half of the 60’s. There was plenty written about rocketry, but very little about the propellants themselves, and nothing at all written about why these specific substances and not something else were being used. John Clark — having run a laboratory doing propellant research for seventeen years — had a unique perspective of the whole business and took the time to write IGNITION! An Informal History of Liquid Rocket Propellants.

Liquid rocket propellant was in two parts: a fuel and an oxidizer. The combination is hypergolic; that is, the two spontaneously ignite and burn upon contact with each other. As an example of the kinds of details that mattered (i.e. all of them), the combustion process had to be rapid and complete. If the two liquids flow into the combustion chamber and ignite immediately, that’s good. If they form a small puddle and then ignite, that’s bad. There are myriad other considerations as well; the fuel must burn at a manageable temperature (so as not to destroy the motor), the energy density of the fuel must be high enough to be a practical fuel in the first place, and so on.

The actual process of discovering exactly what materials to use and how precisely to make them work in a rocket motor was the very essence of the phrase “the devil is in the details.” For every potential solution, there was a mountain of dead-end possibilities that tantalizingly, infuriatingly, almost worked.

The first reliable, workable propellant combination was Aniline and Red Fuming Nitric Acid (RFNA). “It had the one – but magnificent – virtue that it worked,” writes Clark. “Otherwise it was an abomination.” Aniline was difficult to procure, ferociously poisonous and rapidly absorbed through skin, and froze at an inconvenient -6.2 Celsius which limited it to warm weather only. RFNA was fantastically corrosive, and this alone went on to cause no end of problems. It couldn’t be left sitting in a rocket tank waiting to be used for too long, because after a while you wouldn’t have a tank left. It needed to be periodically vented while in storage. Pouring it gave off dense clouds of remarkably toxic gas. This propellant would go on to cause incredibly costly and dangerous problems, but it worked. Still, no one wanted to put up with any of it one moment longer than they absolutely had to. As a result, that combination was not much more than a first step in the whole process; there was plenty of work left to do.

By the mid-sixties, liquid rocket propellant was a solved problem and the propellant community had pretty much worked themselves out of a job. Happily, a result of that work was this book; it captures history and detail that otherwise would simply have disappeared.

Clark has a gift for writing, and the book is easy to read and full of amusing (and eye-widening) anecdotes. Clark doesn’t skimp on the scientific background, but always in an accessible way. It’s interesting, it’s relevant, it’s relatable, and there is plenty to learn about how hard scientific and engineering development actually gets done. Download the PDF onto your favorite device. You’ll find it well worth the handful of evenings it takes to read through it.

Watch The Diesel Effect in Ballistic Gelatin

A striking video appears to demonstrate an explosion via the diesel effect in clear ballistic gel. The diesel effect or “dieseling” refers to when a substance ignites from the effects of pressure, and it’s the operating principle behind the gadgets known as Fire Sticks or Fire Pistons.

diesel-effect-ballistics-gelBallistic gel is a broad term referring to a large chunk of dense gel generally used in firearms-related testing to reliably and consistently measure things like bullet deformation, fragmentation, and impact. It’s tough, elastic, and in many ways resembles a gigantic gummi bear. Fans of Mythbusters (or certain DIY railguns) will recognize the stuff. Water-based blocks made with natural gelatin can be easily made at home, but end up with a yellow-brown color and have a limited shelf life due to evaporation. Clear blocks exist that are oil-based and don’t dry out like the water-based ones. It’s one of these that is in the embedded animation below.

Slow motion video capture is a natural companion to just about anything that you’d need ballistic gel for, and good thing — because the video captured what appears to be a diesel effect! The block is hit with a bullet, and as the bullet rapidly expands and dumps its energy into the gel, a cavity expands rapidly. During this process, some of the (oil-based) material in the cavity has been vaporized. After the expanded bullet exits (to the right of the gif above but easier to see in the video below), the cavity in the block begins to collapse. The resulting pressure increase appears to ignite the vaporized material, which explodes with a flash followed by some exhaust.

This effect has been observed in ballistic gel before, but this video shows a particularly clear ignition, followed by a secondary expansion of the cavity, then a flatulent-ish ejection of exhaust as the cavity collapses. If nothing else, it’s a very striking effect clearly captured on film. Slow-motion capture of destructive forces makes visible many things that would otherwise happen too quickly to perceive.

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Hack a Lock, Get a Free Car?

No, we’re not talking about any lock, or car for that matter. The creators of Loxet are so confident in their product, a smart lock for your car, they’ve issued a challenge to the world. If you can defeat it, you can keep the car — sadly the car isn’t anything special though.

The device, after installed on your vehicle, gives you a taste of the premium lifestyle of fancy push-to-start vehicles. It automatically unlocks your vehicle when you come near with your cellphone, and only your cellphone. It also has the option to give access to friends and family using an invite system. It controls ignition access, and works as a proximity lock.

The car is located at ul. Straszewskiego 14 in Krakow. If you’re not from Poland, [Matt] recommends you team up with a local to try your hack. The alternate prize (if you’re not from Poland or don’t want the car) is $2000.

The car is just sitting there. We’d love to see some 1st person attempts from any of our Polish readers living in Krakow! It is currently set to unlock and lock every 10 minutes. You might be able to get into the vehicle — but will you be able to take it? Let us know!

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[Mehdi’s] Shocking Stun Gun Tutorial

[Mehdi Sadaghdar] never lets little things like fire, shocks, or singed fingers get in the way of his projects.  His latest is a tutorial on making a simple electroshock device. A stun weapon creates a very high voltage, and is used in law enforcement to temporarily disable a person. [Mehdi] stresses repeatedly to not use this on anyone. If you do, he won’t like you anymore. Of course, if you’ve seen any of his previous videos, you know he’ll shock himself and set something on fire before the project is complete.

To create his stunner, [Mehdi] used a car ignition to produce a high voltage. The igniton coil, which is a specialized transformer, allowed him to generate the >10000V output needed for the stunner. The coil has a 60:1 ratio and is powered by a 12V DC supply. Since a coil is a short at DC, the system only creates a high voltage pulse when power is disconnected. However, the pulse was too short to create a satisfying arc. [Mehdi] added a capacitor, creating an LC circuit that oscillates as the charge decays, creating a nicer spark. He then used an RC circuit and a relay to create a simple oscillating switch. For the finishing touch, he created a spark gap on the secondary of the transformer with two nails. In typical [Mehdi] fashion, he nearly fried his digital caliper in the process.

The end result is a nice spark that warms the cockles of [Mehdi’s] fibrillating heart. We commend him for being such a brave masochist in the name of science.  Check out his tutorial after the break!

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Using a screwdriver to start your car

screwdriver-key

[Hahabird] uses this screwdriver to start his car. Despite what it may look like, only this particular screwdriver will start the ignition because it still uses the key lock. What he’s done is alter the screwdriver to act as an extension for the key. It’s purely aesthetic, but you have to admit it looks pretty gnarly hanging off of the steering column.

The hack merely involved cutting off the unneeded parts of the key and screwdriver. With the shaft of the tool cut down to size he clamped it in a vice and cut a slot into it using a hack saw. From there he headed over to the grinding wheel and smoothed out the sharp edges.

The key itself had the handle portion cut off and was thinned on the grinding wheel to fit snugly in the screwdriver slot. To permanently mate the two pieces he used a torch and some silver solder.

[via Reddit]

Adding keypad security to your automobile’s ignition system

[BadWolf] managed to make some free time to get back to his own electronic projects. This time around he’s created a security system for his car. It’s patched into the ignition, preventing the engine from starting when the key is turned. A driver must first insert the key, then type the combination on a keypad in the center console before the car will fire up.

While he was working on the project he also decided to add a start button to the dash-board (we think it does make it look like a later model vehicle). The keypad is driven by an Arduino Nano which has the start code stored in it. Power for the system is provided by a USB hub hidden behind the dash which he thinks will also come in handy with future hacks.

When the proper code is entered, you’ll hear a rendition of the Super Mario Bros. theme. The speaker also lends a pleasant beep with each keypress. See the demo clip after the break to hear it for yourself.

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Jeep-uter adds push button control to your vehicle

[Ed Zarick] built a module to control his vehicle which he calls the Jeeputer. The name’s a mash-up of Jeep and Computer; the device itself is a combination of Arduino, character LCD, and a collection of shift registers and relays for interfacing. Watch the video after the break to see what this can do. We were surprised in the beginning when he says that all he has left to do is remove the steering wheel lock and he’ll be able to drive using the interface, but we think he means type in a code to unlock the ignition, not remote control for his car. He then goes on to demonstrate garage door control, power cycling for CB radio, GPS, 110V power inverter, vehicle light control, and much more. This must be the most feature packed car computer we’ve seen so far.

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