The flamethrower was impressive!

I am a pansy in at least one sense, and I love flames. WhaddayamakeaTHAT?

Xopher - that you're a flaming pansy? [ducks, runs away]

re: jacob's ladders
My many-years-back memory says it's a step-up transformer; I've seen it demonstrated at least once. But it does require a hefty output voltage.

I had one physics class where we used a ABC power supply unit (that's the supply rating) and a large dry cell to run a cathode-ray tube. The dry cell was the hot spot in the setup, although the power supply was much higher voltage. I seem to recall that it was running about 1 kilovolt out of the supply unit, for a maximum deflection of maybe four centimeters.

Grrrr! I'm a Premium Subscriber and Teresa was able to buy a copy first! Hisss!

A future issue should have an article on how to build a disappointingly safe and sane PVC model rocket launch pad.

* * *

A college friend built a Jacobs Ladder when he was getting his degree at Texas Methodist. He and his roommate used it for infernal purposes. The figured that, if you laid pennies around the base, you could create a pretty light show and make the neighbor's phone ring. Continuously.

I'm with Xopher. Big homo, check; things going boom, check. Pyromaniac pansies of the world, represent!

I checked my husband's temperature last night. He had tossed the mail into the hallway basket without looking through it closely enough to find his copy of MAKE.

Similar in some respects to the PVC flamethrower, I discovered that I had actually built a pneumatic poodle launcher (actually, any small animal would suffice) while trying to construct a prototype active plethysmograph. But the addition of fire just raises the whole PVC weapon threshold to a giddy new height.

Love you guys.

Way back in high school, a friend built a PVC bazooka that used lighter fluid to launch tennis balls. I suppose hamsters would've worked as well.

prototype active plethysmograph

What is a plethysmograph? Just from curiosity, you understand.

(I remember hearing Dr Jerry [Pournelle] talking about soaking the desk blotter for one of his teachers in nitrogen tri-iodide, said teacher having the habit of whacking it with a ruler. Fans like things that go bang!)

Hm, maybe I should talk to my landlord about building a Jacob's ladder...

To quote Marvin the Martian:

"There was supposed to be a big Earth-shattering ka-boom."

My first-year college room mate and some friends made pvc swords. We went ot the park and beat the crap out of one another. It was fun, but nowhere neear as fun as if we had had flamethrowers.

Now if I just didn't have a toddler in the house, I could make that flamethrower.

*chases protected static around with fire-poi*

My former housemate makes shoulder-mounted PVC rocket launchers. They use a battery operated trigger to ignite and launch model rocket engines. It's like G.I. Joe for grownups.

I think I'll show him this thread.

Then there was the time one of the other housemates let it off in the house...

I'm actually not a big fan of loud booms. What I really like is the sound big wads of burning oil-soaked kevlar make as they whiz by my ears.

Whoosh. Zhhhooom.

I once read about a fellow who made the mistake of inserting an electric match igniter into the nozzle of an "I"* class model rocket motor.

Electric matches can, under freak circumstances, be set off by radio waves or static electricity.

This happened.

While still in his hotel room. With his dog and wife present.

The rocketeer managed to hang onto the motor for the duration of the burn, aiming the nozzle at the corner of the room least likely to contain burnable objects and/or loved ones.

No one was injured. I imagine they had to clean the carpet. Maybe in several spots.

The victim / perp wrote up the incident himself, for the edification of others tempted to save time at the expense of safety.

Stefan

* An "I" has at least 32 times the total get-up-and-go as the little model rocket motors sold in stores.

Ooooh... fire juggling...

I've always been more of a loud boom guy, myself - but there's definitely a time and place for plain-old fire.

Yes, there is. All around me, as often as possible.

So, I sent these links to my friend and he wrote back this:

"You're a bad bad person for sending me these. Now I have to build them."

Heehee. Not a pyro myself, but I suppose I'm a bit of an enabler.

Y'all know how to make rockets from a paper match, some aluminum foil, and a pin, with a bent paperclip as a launch rack, right?

Take the match. Lay the pin along its length with the point up at the matchhead. Wrap the top half of the match in aluminum foil. Remove the pin (leaving a nozzle). Put the foil-wrapped match on a partly unbent paperclip, aimed up at about a 45-degree angle.

Heat the foil with another match. When the match ignites, it flies! Hurrah!

But that isn't the point of this post. If you do have a toddler around the house, here are workshop plans for building said toddler a working scale model Sherman Tank with firing main gun:

http://www.gizmology.net/tanks.htm

"If you do have a toddler around the house . . ."

OK.

That settles it.

My parents didn't love me when I was a kid.

If they did, they would have built one of these tanks for me. If they cared it would have utterly obvious that this was what they should have done.

Hey, I'm not bitter. They got me a grey polyester blend suit from Sears when I graduated college.

I was going to put this over on the "To the Artist..." thread, but this one's newer and shorter:

The folks at Fiddler's Green, mentioned over there, have a paper model of the Norge, the blimp that took Roald Amundsen and the unfortunate General Umberto Nobile over the North Pole in 1926.

This is a big darn model, 29" long. I'm pretty sure it would fly if the envelope were sealed and filled with not-hydrogen* (or if you cleverly constructed it so a helium balloon could be tucked inside). Control, of both the model and any high-strung cats in the room, are left as exercises for the reader.

*You can fill your paper Hindenburg with whatever explodes your boat. Once, in the Smithsonian Air & Space LTA hall, I heard a gentleman loudly explain to his family that them Krauts were too stupid to put helium in their airships. I decided it was not a discussion I wanted to contribute to.

Hydrogen would be fine -- it was the outside that burned, not the hydrogen.

Xopher writes:

I'm actually not a big fan of loud booms. What I really like is the sound big wads of burning oil-soaked kevlar make as they whiz by my ears.

Whoosh. Zhhhooom.

Though many of you have seen it before, I must here contribute my all-time favorite Jon Singer quote:

"The sharp, 'Krac!'-type explosions don't do it for me,
and the big rumbly booms only partly do it,
but a good solid 'KBAM!'
just makes me fall over laughing."

BSD: As I've heard it put, "Don't paint your aircraft's envelope with rocket fuel, and you should be okay."

Things that go boom, or things that go whoosh, or just Whoomp!.

Bliss.

Mighty white of you to except the Taunton Press. Keen use of hovering whatsits with the asterisk though. And the article on manufacturing your own security bits was worth the price of admission by itself. I've got some battery powered keypad doorlocks that require a special bit, and if the inimitable Hardwick's Hardware (of course you know from Hardwick's, yes?) does not yield a set of the bits then at least I now have an alternative. This is of a goodness.

The Make:Blog is one of my favorite reads of the day. While I don't dabble in pyromania or PVC cannon-type devices, my brother does. I feed him info and store up links for the days I have the time and inclination to work on them.

Good stuff.

I found many years ago that one of the best ways to make an earth-shattering kaboom doesn't require explosives at all. Just drop a pumpkin off the top of the Green Building (MIT Earth-Sci; 22? stories tall). (No, I didn't get to drop it; I was just there.) It made a much more impressive noise than the howitzers used each year for the 1812 Overture.

One of my Train People says that Model T ignition coils are good for building Jacob's Ladders. He says they're also good for starting Tesla coils. (Warning: your neighbors won't appreciate the Tesla coil as they should. High in RFI.)

Teresa, you are my daughter's idol. She says, if she was half as cool as you (or me, but she's hallucinating there) she would not be upset with her life. "Flamethrowers are awesome!"

Clearly her father's daughter. Quadroon toon.

I'm delighted to find such a wonderful thread on Making Light as I'm spending tonight trapped in the Swedish Hospital Sleep Clinic. It brought wonderful things to mind such as my very favorite birthday present from my husband, my rifled PVC potato gun. It's wonderful, it has gauges, and tubing, and looks like a Star Wars double-barreled bazooka. It doesn't make a large boom - just a phoot! as the potato leaves the barrel.

P.S. Bruce, if you're reading this, yes, you can subscribe to Make.

Building 20, CHip, the Cecil and Ida Green Building. I don't remember seeing you there at the pumpkin drop(s) which my dormfloor did. I don't remember the noise, but I do remember the circular wavefront of mashed pumpkin with the proper Bessel function zero rings.... somewhere or other I have a couple of (blurry, because they were taken at night with a long exposure with the camera hand-held) pictures of the results).

Other things my floormates dropped included a lead brick (it bounced, it got deformed, and it had heated up quite a bit) and a small refrigerator.... and then there was the time Roberts lit off his miniature replica cannon, which being a black powder weapon, was not technically banned from being shot off from a dorm...

Someday I have a bar trick (former bar trick, that is) I want to show off to some people, I keep forgetting about that, though... it is not something I expect I will ever again do it in a bar, it will be obvious why to anyone I get to successfully demonstrate it to... (it was one of the the I learned in a military bar.... not that I expect it would be allowed in even those, anymore! (and no, I'm not talking about "afterburners" which I don't expect I will ever drink, or attempt to drink, another of, I survived essentially unscathed the ones I did drink w/h/e/n y/o/u/n/g a/n/d s/t/u/p/i/d, though perhaps sheer dumb luck, not all people who tried were so fortunate (I only heard about the unfortunate results cases, never saw one for myself, or "carrier landings" which I never tried myself, but did witness (without the obstacle of broken glasses, however, the version I saw was not the true Vietnam War military bar version....)

The Model T ignition coil for high-voltage output: a long time ago in a model rail article, the great Frank Ellison (which makes it a long time ago) described using one in a trackside diorama of a welding shop. Wire in hand of welder figure, large metal pipe for him to work on. Add switch, either manual or (given the period) a rotating disk with a moving contact. Hey presto, actinic spark. This would have been in O scale -- in HO the spark would be more appropriate to Dr. Frankenstein's (or maybe Dr. Franklin's*) laboratory. And he did suggest that you surround it with non-flammable stuff (dirt, metal junk) and arrange it so that the spark wouldn't be in direct view; the flare against the shop interior, and casting shadows, would be as effective.

*Not the one from Babylon 5.

I just received the "other" theremin kit in the mail, the kit sold by an Australian guy. I saw people playing theremins in the Moog documentary, and I just had to have one. I doubt this one will be as good as the Moog Etherwave kit, but at $95 + shipping it's under 1/3 the price, so I can kind of afford it. (I bought it as a reward to myself for landing/completing my first freelance coding job. It's motivational, damn it!)

First impressions: Tiny little thing. Further impressions after I actually build it and try it out.

I recall Dad building a scoop with spring-powered launcher, for purposes of yard cleanup after a neighbor's dog. (This was at my aunt's house.)

Dad and my uncle put the thing quietly away after missing the target of the neighbor's lawn and hitting their roof.

Friend of mine built a shoulder-fired rocket launcher with an NI3 payload because he was tired of having to walk round the outside of the field with the bull in it on his way to school, and reckoned that a startled, slightly singed bull coloured purple over one flank would be less of a threat. Stability was the problem, though - couldn't get the projectile to fly straight enough. (Test flights were very unsatisfactory. Think of that sequence in 'The Right Stuff'; like that.)
Ah, NI3. There's a time in every boy's life when he finds out what can be done with, as Burt Gummer said, "just a few household chemicals in the proper proportions". (nostalgic *sniff*)

Potato guns are good fun too. Pipe; valve; flammable gas canister; igniter; potato (or orange, honeydew melon, etc). Guys I dived with used to bring one along. One time they got the beers in on a night dive and sat on the beach firing it at the rest of us as we struggled ashore. Great long blooms of fire from the muzzle and splashes of overripe oranges landing near us in the surf - it was like a very low-budget version of Saving Private Ryan.

It used to be that the interpretation of British law on bomb-making made model rockets -- even the safe commercial sort -- illegal. Putting the motor in the model was seen as making an explosive device. Eventually that changed.

I'm not sure if I want to find out the current status of some of those sites you're linking to, in a world where the Police want laws to ban toy guns.

So, be careful out there. We're living in a crazy world.

Dave -- indeed we are. Which means that I didn't, while a student, make a biro mortar by filling one end of a thin PVC tube with black powder, adding a biro and ramming it down, placing firmly on the ground (not pointing upwards or at anything... delicate) and igniting it using a device formed from a crushed 12v incandescent lightbulb and grated match heads.

Nor did I launch a rocket made from a steel drink can tied to a piece of wood with similar fuel to the primer in that igniter. It didn't clear the roof of a nearby 3 story building.

(I would particularly disrecommend the latter as unsafe unless you are at a very respectful distance, BTW)

Why is pyromania the #1 correlate of wierdness?
All myriad, divergent, little-else-in-common kinds of NOT-normal seem to be pyros.
Why?

And the Best Novel About Flamethrowers is:

MOST SECRET, by Nevil Shute

(Also has one of the more interesting narrative methods I've seen. Chronological overall, but non-chronological in terms of the characters.)

Considering the explosive tone of this thread... People might want to take a look at tonight's new episode of Mythbusters on the Discovery Channel. Adam & Jaimie explore the possibility that Johnny Reb had a secret weapon involving rocketry. They probably won't top the time they strapped their dummy Buster to a Chinese rocket chair, nor the time they put a few hundred pounds of explosive inside a concrete mixer, but one takes one's kabooms where one can find them.

"Way back in high school, a friend built a PVC bazooka that used lighter fluid to launch tennis balls. I suppose hamsters would've worked as well."

This made me laugh hysterically, at least partially because it reminded me of the brilliant* Outpost.com commercial with the gerbil cannon. For anyone who hasn't seen it, they basically cut out the second 'O' and then fired gerbils, from a cannon, trying to get them through the 'O'. My favorite bit of the commercial was the "pkow" of the cannon, followed by the "thip" of the gerbils hitting the backdrop, and then the "squee" as they scampered away. The super at the end of the commercial directed all complaints to outpost.com, and, as I've heard it, traffic tripled overnight.
I miss commercials like that.

*ymmv, of course.

Oh my goodness. I've never heard of this MAKE magazine before. And there are four issues out? Ghah!

WANT!

Oh, I've heard the story about the CSA rocketry...

What would be plausible would be some sort of field artillery rocket, as deployed by the British in the Napoieonic Wars, with the advantage of better engineering. There were British rockets fired in North America. as our patriotic readers well know, but the Congreve rockets were not all that reliable.

(Pauses to make offering to Google)

Apparently, the Hale rocket was used by US forces in the war against Mexico.

Anyway, I can see enthusiasts on both sides advocating the use of rockets, even really big rockets, and I s'pose the story just growed.

I knew that rockets had been used in the Napoleonic Wars. (I remember that episode of Sharpe where Sean Bean's character was less than impressed by the geeks in charge of the rather erratic rockets although they did pull thru eventually.)

I'm not sure what would then be special about the Confederates using them. Then again the MythBusters are always game for any excuse to blow things up, even a Portolet.

the "other" theremin kit

There's a company called PAiA (www.paaia.com) which sells theremin kits, with case parts, for about US$90.

Then again the MythBusters are always game for any excuse to blow things up, even a Portolet.

I think you mean, "especially" a Portolet. How could you improve on blowing up a portable toilet? Aside from filling it with watermelons first, of course.

I just outright bought my theremin, not being an electronics whiz. Since I'm not an instrument whiz, either, I never managed to actually get music to come out of it.

Wonder who I know who IS an instrument whiz and would like to come play it, or invite me to bring it over (it's not heavy)?

HINT.

How could you improve on blowing up a portable toilet? Aside from filling it with watermelons...

Why, by putting the appropriate person IN the portable toilet, of course. I've got a little list...

Ah, Mythbusters. Can I just say how much we love that show? The husband and I only discovered it a couple months back, and we've been TiVo-ing it with abandon.

Mythbusters is geek porn.

There is an account in the diary of one of Jackson's aides -- it's quoted in Jack Coggins's Arms and Equipment of the Civil War -- about the one use of Congreve rockets by the Confederacy. It wasn't much of a success, but it's not mythical. The Congreve is a big, unwieldy object, and the words "precision-guided munition" are not spoken in its neighborhood; they are mainly useful for sieges, and the Confederacy didn't do a lot of besieging.

And of course they were used by the British in the War of 1812, to attack Fort McHenry, where they are famous for glaring redly, if you get my drift.

Back to Coggins: The Confederate diarist says that "Some British chap had gotten it up for the occasion." The friend I was looking at the book with and I having both read Flashman at the Charge, we at once looked at each other and said something to the effect of "Naaaah. Couldn't be him."

Thanks for the info, John. As for tonight's MythBusters, since rockets WERE used, I'm not sure what exactly what 'myth' they'll be exploring, but we shall see. And things will go kaboom.

Last week they tested the case of the Flaming Canadian Air Force pilots. Apparently there was this pilot who enjoyed using hair cream even when flying. So, one day, off he goes into the blue yonder, until a spark in his helmet's doodads makes his hair catch fire and blows his head off. The MBs tested the plausibility of that with their usual maniacal approach. It turns out that yes, your brylcreemed hair will indeed catch fire. But no decapitation.

Well, the Discovery Channel website says that the Confederate rocket in question was to be launched from Richmond at Washington. A hundred-mile-plus range would indeed be impressive.

And the digital-cable guide says that it was "steam-powered." Now I'm beginning to think this story is from Earth-Artemus Gordon (which is apparently also the setting of the new Zorro movie). Or perhaps it was designed by the Native American scientist immortalized in an episode of Hoppity Hooper, Wernher von Braunbear.

Hoppity Hooper ?

A rocket with a 100-mile range in the mid-19th Century. Yeah, that would have been impressive. Heck, what was the range of the V-1?

This is starting to sound like the premise of a Turtledove novel. Until one comes across the part about the rocket being steam-powered... Then, yes, this sounds like something from The Wild Wild West. Miguelito Loveles, anyone?

Hoppity Hooper was an attempt to bring Rocky and Bullwinkle-style comic adventure into the world of frogs.

It was not a success.

The V-1 (or, as its friends called it, the Fieseler Fi-103) had a range of about 240 Km (150 mi.). There were some late models that could make 370 Km, but only a handful of those flew.

A powered glider would probably have been the best way of getting long range . . . if glider technology had been advanced enough in the 1860s. If one were going to speculate about aërial kaboomery during that war, balloons with impact fused bombs (extant, though very unreliable) would seem the likeliest -- probably windborne, though the obvious Seceshpunk image is of one with a furiously asthmatic steam engine (its exhaust keeping the envelope heated), trailing black smoke crookedly across the sky on its way to wreak heavenly fury.

I probably shouldn't get started on the long and dismal history of the Double-Barrelled Cannon Firing Linked Projectiles -- which during that war actually killed somebody, if you consider a cow "somebody."

Yes, John, do get started on the long and dismal history of the Double-Barrelled Cannon Firing Linked Projectiles. Sounds quite interesting. Were they the ancestors of Big Bertha?

Civil War Rockets:

By the start of the Civil War in 1860, military rockets had all but disappeared. Rockets declined in importance due to the deadly accuracy of conventional artillery, most notably weapons with rifled barrels and breech loading. However, both sides in the Civil War remembered how well rockets served armed forces during the Mexican War two decades earlier. But, it was quickly discovered that Hale, and even Congreve, rockets that had been stored for long periods of time were rendered useless because their gunpowder charges failed to remain properly bonded to their casings.

This forced both sides to develop new rockets if rockets were to be used at all. The resulting rockets were considered primitive, even by the standards of the day, due to their inaccuracy and unreliability. But, a variety of rockets were used during the Civil War by both sides. On July 3, 1862 Confederate forces under the command of Jeb Stuart fired rockets at Union troops during the Battle of Harrison's Landing. Colonel James T. Kirk of the 10th Pennsylvania Reserves later wrote that one of his men was wounded by a projectile carried on a rocket fired from "a sort of gun carriage". Rocket batteries of this type were most often used by Confederate forces in Texas during campaigns in 1863 and 1864. These rockets and their launchers were first manufactured in Galveston, and later in Houston. The New York Rocket Battalion was the first Union force to be issued rockets. The group was organized by British officer Major Thomas W. Lion and was made up of 160 men. Rockets employed ranged in size from 12 to 20 inches long by 2 to 3 inches wide.

The rockets could be launched from light carriages carrying four wrought iron tubes, each of which was about 8 feet long. They could also be launched from 3.25-inch diameter guiding rods bound together in an open framework, or from individual 3-inch diameter sheet-iron tubes. Each rocket was primarily designed to deliver flammable compounds, but could carry musket balls placed in a hollow shell and exploded by a timed fuse. Although the New York Battalion rockets could fly a remarkable maximum distance of 3 miles, they were extremely erratic and were never used in combat.

Apparently the rockets from Texas were built under the direction of a Swiss-American engineer named Kellenberg or Kellenberger; there's a website dedicated to him.

Excellent! Whole new, creative ways in which I can hurt myself, duly bookmarked for later (-:

-Suzanne

"It was not a success."

However, I now have the theme song going through my head.

Thanks.

Thanks a lot.

I can't remember the theme song. Neener, I say, neener neener.

P J Evans asked:

"What is a plethysmograph?"

Dictionary.com has a pretty good definition.

An instrument that measures variations in the size of an organ or body part on the basis of the amount of blood passing through or present in the part.

The fun part is imagining exactly how we got from that to "pneumatic poodle launcher".

An instrument that measures variations in the size of an organ or body part on the basis of the amount of blood passing through or present in the part.

It sounds really invasive to me. (I don't like shots, either; YMMV.)

Knowing how there had to be some historical reference for every name in Star Trek, so the studio lawyers could point to it and sneer at any litigant, I wonder if that Colonel of the Pennsylvania Reserves was the official source for Captain Kirk.

C.H. Gibbs-Smith gives 1852 for the first practical airship, built by Henri Giffard; powered by a steam engine, it could make 5mph. By 1860 there had been some steam engines with impressive power/weight ratios built - a practical payload would probably have been possible. I've no idea what the ballpark range would have been.

As with so many revolutionary ideas *cough*V-weapons*cough*, the effort involved in getting it to work would be better spent on building more conventional weapons; field guns and the like. The most profitable use of balloons would have been for aerial observation, in which role I believe a few were employed - my American Civil War knowledge is patchy at best.

Cicada> Excellent! Whole new, creative ways in which I can hurt myself, duly bookmarked for later (-:

(Not meaning to pick on you, but it makes me physically uncomfortable to discuss playing with fire without throwing some safety talk in.) My experience is in fire juggling, which is to say liquid fuel and low flame temperatures, but these are a few guidelines I find useful:

Distinguish between safe area, prep and assembly area, and performance area. (The performance area may also be temporally distinct.)

No flames or sparks anywhere at all except in performance (performance includes testing). No fuel in the safe area, and keep your medical resources and your spare person looking out for trouble here, too.

If in doubt, abort.

Only keep as much fuel on hand as you will actually use; if you need more, shut the whole performance down while moving it from secure store to prep and assembly.

Think about your clothing: natural fabrics char, most synthetics melt. Melting is worse.

If in doubt, abort.

…you would not believe how much better I feel for that. Shame I couldn't find something more interesting for first comment here, but hey. Now I shall go and set my laundry on fire. It's a renewable resource, y'know.

Hmmm, wish I'd seen that Paia theremin kit before I ordered this one. It looks a bit better value for the money. No problem though, any kind and size will be cool.

Xopher: You don't need to be an electronics whiz to solder parts according to instructions!

Heavens above. Here was I, thinking that the Great Panjandrum and the Bates six-barrel bottlethrower and the Roman Army's anti-elephant cart (and Mithradites' scythed chariot corps) were the most egregiously idiotic military devices in history, and now Mr Ford speaks of the double-barrelled cannon firing linked projectiles.

The mind boggles.

"The victim / perp wrote up the incident himself, for the edification of others tempted to save time at the expense of safety."

This is of the "learn from other people's mistakes; you don't have time to do them all yourself" variety.
---------
I am reminded of the look of unholy glee a young friend of mine got when I explained about NI3. He had been telling me about his potato cannon. I told him he should paint large boulders with NI3 and fire potatoes at them. He thought this much more fun than firing potatoes at the double metal doors of his school, setting off the security alarms.

He then shared with me the story of the ballista used to launch a large chunk of metallic sodium into the pool. The pool next to the group of teachers celebrating having survived another year of school. The pool that lost about a third of its water, half drowning the teachers and completely drowning their feeling of survival.

I have put the assorted links in this thread under a new category in Favorites: Toys.

Damn, I love this place!

Well, the Smith Gun was quite enough...

It fired anti-tank grenades.

Which were a glass bottle containing an incendiary mix which included benzene and white phosphorous.

And it actually saw service with the Home Guard. It is reported that if a bottle broke in the barrel you had to pay attention to the wind direction when opening the breech.

Compared to that, the Blacker Bombard was wonderful.

Plethysmograph: An instrument for determining and registering the variations in the size or volume of an organ or body part and the variations in the amount of blood in it.
Some pix of different models: early version; one in use for thoracic medicine (lung capacity); a multi-channel plethysmograph

Although these, and versions like the air displacement plethysmograph, which assesses infant body composition, or Impedance Plethysmographs measure the impedance of body tissue in response to blood flow, useful as blood pressure sensors which can just be attached to a finger, or adapted for measuring blood flow or oxygen balance non-invasively* in various situations, are used mostly for humans [especially the penile plethysmograph, which has some rather dubious applications], there are many applications involving non-human animals.

Looking at pictures of some of these, I can imagine adaptation for poodle launching occurring to the prepared mind.

John M Ford referred to "balloons with impact fused bombs (extant, though very unreliable)". I presume that extant refers to the "Fu-Go", Japanese balloon bombing of the USA in World War II, which resulted in the only direct mainland US deaths in that war. (Note that, like the great majority of snakebites in Australia, these were caused by the actions of the victims unfortunately interfering with Something Best Left Alone.)

The thing to remember about the Home Guard is that it wasn't (as in 'Dad's Army') a collection of old men and sickly boys - since it was a part-time force, it could draw on everyone.
Members included: Socialist veterans of the Spanish Civil War who had interesting ideas about killing tanks with fougasse; gamekeepers (and poachers) with 12-bore shotguns firing solid shot; any number of Great War veterans now too old or whose jobs were too important to be conscripted; scarily enthusiastic seventeen-year-olds waiting until they were old enough to enlist; University chemists who made pyro devices in their spare time... I suppose the best way to put it would be "A moderately-well regulated militia". Or "Making Light in puttees".

I too am curious about the evolutionary chain from "attempted active plethysmograph" to "pneumatic poodle thrower".

I can think of a couple of ways that a rocket could be described as steam-powered. Either it was launched from a steam catapult of some sort and either had a solid fuel sustainer motor or was just a glider (not really a rocket in that case, more a winged projectile from a steam cannon), or it was powered by hydrogen peroxide over a silver catalyst decomposing into water (or rather steam) plus oxygen. But I've no idea whether either would have been possible in the 1860s.

As to the joys of many of these things, I will remain silent. DHS, and all that. I will remark, however, Olson's Fourth Observation: The fundamental difference between smart people and stupid people is that smart people get to do stupid things more than once.

As to ad-hackery, last project was converting the BSD Desktop to SCSI storage. BOR-ING. The project before that was a headphone amplifier optimized to drive headphones with very low input impedance (namely, Grados.) I'm still deciding if it is done (so I can hook up the volume pot and close the case) or if it could stand BUF-634 buffers on the output channels (the ground is already buffered.)

And, of course, if I make that change, we start the whole cycle of "try these op amps, change this bias resistor, etc. etc." Fortunatly, the Grados have more than enough detail to make many of these changes instantly obvious, and since this is my headphone amp, for my ears, the only real spec is "Does it sound better or worse to me?"

HTH. HAND. And don't throw chainsaws into volcanos.

John -- thanks for the advice. Though in all honesty, having accidentally lit my own head on fire once*, I'm not inclined to do anything likely to cause me to repeat that experience.

(* in some places, having long hair is a detriment. Working in a foundry is one of those places)

Well, no kaboom yesterday night when the MythBusters tested their Civil War rocketry. But impressive. Especially when Jaimie's gunpowder-using Hale rocket flew off and landed about 3 miles away and 5 feet into the ground. Good thing they did this near Edwards.

As for the rocket with a 100-mile range... The actual range was wayyyyyy less than the planned one, but it was quite a sight. And it showed that the Civil War could have used liquid-fuel rockets. Not liquid oxygen because that technology wasn't available the 1890s, but the liquifaction of nitrous oxyde was.

Overall, an impressive show.

I am reminded that Someone Else's Backyard (the bigger, the better) is the place to do many of these things. Although I will say that 5 acres of easement/cornfield/woods is a pretty decent place to play with a 5 ft spudgun. (Although it does spook the deer.)

Erik- throwing chainsaws into volcanoes is fine. Just use a launcher. And make sure you know what the alloy of the body is.

Cicada- that's what ponytails and hardhats are for. Only needed one person in foundry lab to get a spark in his hair, and the rest of them bundled their hair up under the hardhat. To this day, I still don't know whether Dennis was using him as an example or not. That was one of the few times that Dennis had sparks flying during a pour.

For those in the mood for a little PVC fun but not quite ready to risk a lengthy vaction in the burn ward, here's instructions for making a Mark II Potato gun (reportedly ~10x power of your regular spud cannon)

http://www.thebugshop.org/othersites/airspud/airspud_home.html

A guy in my office reports eminently satisfactory results.

Liquefied nitrous oxide? Hmm. Interesting. So the 'steam-powered' thing was just a misunderstanding?

For playing with this sort of thing in general, the best place is generally a deserted beach - assuming you don't want to retrieve any projectiles. Also has ample supplies of a) sand and b) water for firefighting. Of course, not everyone lives close to a deserted beach. Forest is not quite so good because you can't check it's empty as easily; also forest burns, unlike sand and water.

On the grounds of silly weaponry; anyone interested in the Napoleonic period will have heard of Thomas, Lord Cochrane, model for Jack Aubrey, cousin of the man who burned the White House and inventor of the explosion ship.

It works like this: you know fireships? You take an old brig, at the end of its useful life, pack it full of pitch and pyro, get a skeleton crew of volunteers and sail it into the middle of the French fleet at anchor, light the fuses, and then get into the lifeboat and row away as it drifts into the moored ships and sets them on fire? You do? Right.
What we do is, we get an old brig and we put in it, say, fifteen hundred barrels of powder. Yes, fifteen hundred. Then you get about two thousand 13-inch mortar shells and put 'em on top. Have we got any hand grenades? We have? Good. What's that? How many would I like? Ooh, all of them, I think. Get some Congreve rockets as well. Yes, I know they're inaccurate. Believe me, it won't matter. Pack it all in fairly tight, and lay out some fuses.
My Lord Admiral, this baby is gonna make 'em wish they'd picked another line of work.

Yup, ajay. Liquified laughing gas.

Speaking of Napoleon, can you name the two movies in which he was played by Ian Holm?

And did you know

Oops... Forget the And did you know of my last post. Darn thing was supposed to have been deleted.

Make magazine has podcasts availabe for free on iTunes.

iTunes is available as a free download, for both Mac and PC, here.

ajay: what with that whole concussive wave, spewing shrapnel, screeching rockets whizzing every-which-way thing going on there, I'm thinking the first ones who're going to wish they'd chosen another line of work will be the crew of aforementioned exploding ship... If anyone else comes out feeling that way, it'd be a happy (for the owners of the explosive brig, not the recipients) accident.

Serge: Time Bandits was the first.
And a comedy from within the last three years was the second.

And IMDB is my friend, but honor demended I work from memory. Now I'll go look it up.

Yes, Patrick, Time bandits indeed is the first movie where Ian Holm played the short guy from Corsica. The other one is The Emperor's New Clothes.

You know, it's kind of funny how Napoleon is shown as a bad guy in American fiction, even though we were on his side, kind of. Where I come from (hint - French is my native language), he's not perceived as a bad guy. Maybe a bit megalomaniac, but nothing like Hitler in the villainy department.

One more bit about the Napoleonic Era... Of all the movies set in those times, would the Hornblower movie with Gregory Peck be considered the most realistic one where naval battles are concerned?

spewing shrapnel

This brings up one of my personal bete noirs:

Shrapnel isn't the same thing as shell fragments. Shrapnel specifically refers to a kind of artillery shell invented by Lieutenant Henry Shrapnel in the late 18th century. You could describe it as long-distance cannister shot. I doubt that it's been used anywhere in the world since the end of WWI, and clearly couldn't exist before its invention.

Erik V. Olson writes:

I will remark, however, Olson's Fourth Observation: The fundamental difference between smart people and stupid people is that smart people get to do stupid things more than once.

I like this. I'm putting it up on the safety department whiteboard here.

HTH. HAND. And don't throw chainsaws into volcanos.

You learned this from Dale, didn't you? Had dinner with him last night. Still appears to have all fingers.

Epacris: no, I was thinking of impact-fused devices extant in the 1860s, which could be used in Confederate Balloons of Doom* aimed (for certain values of the word) at Washington.

There was a lot of entrepreneurial weapons design during that war -- stuff produced in small quantities that individual soldiers could buy from local merchants or sutlers. These infernal devices were not nearly so much Smith & Wesson as Jethro Bodine & Peck's Bad Boy. Among them were various sorts of impact grenades that worked on the principle of placing a percussion cap on a stud and throwing the object; on landing, the cap would, theoretically, detonate a larger charge. (The central principle of modern grenade design, that it isn't how much bang but how many fast-moving bits, was unknown.) Anyway, one of these was a thin cast-iron sphere, roughly softball-sized, filled with black powder, with fourteen such studs on its surface. You put caps on all the studs, put it inside another iron shell, and threw it. If you were smart, you threw it gently. This thing, which doesn't seem to have ever been used in battle, was called the "Excelsior," doubtless because it was a strange device.

Having now seen the Mythbusters episode, it looks like the "steam-powered" bit was the fancy of a blurb writer. And the search for a liquid oxidizer that would have been available to the Confederate Rocket Society** was rather bewildering to those of us who have read up on the subject -- I mean, there was [series of R2-D2 noises].

The thing is, I've been through a lot of material on the war in question, including a good deal of weapons-tech stuff, and I've never once heard this yarn about firing a Newtonacious bolide at Washington. The Confederate Secret Service destroyed a lot of its documents as the end loomed, for understandable reasons, and the postwar Congress might have indeed harbored ill feelings toward people who had tried to bring the war so directly into their oratory and gin-hall, but the Mythbusters generally offer some sort of source.

Though the image of the New Americans peering through a crater-mounted periscope as Neil and Buzz trample their sacred countryside would be worth a sketch.

*Not him, though possibly a Latverian expat ancestor.
**"The Richmond Hypergoldurns."

ajay
At a tall ships gathering recently, they had an exhibit of a Confederate submarine. The idea was to go under the Union fleet, ram a harpoon (with a load of black powder) into a ship under the water-line, move back 200 yards and light the fuse. All well and good. Except...

The harpoon struck the weapons magazine, which was packed to the gills with gunpowder. We were told that the crew of the submarine were instantly pulverized and never knew what hit them.

(Just then, one of the ships playing in the harbor shot off one of its cannons. The timing was impecable!)

My bad re: shrapnel. Learn something new everyday. (Tho' at this point, isn't it like 'kleenex' or 'xerox'? You don't mean the brand, but everyone knows what you mean...)

John:

One does wonder where the MythBusters came up with the idea of the Confederates possibly having had long-range liquid-fuel rockets. Maybe it tells in their blog. I understand that some of their fans are VERY nitpicky.

Maybe they just read something written by some drunkard way back when and they just grabbed that as an excuse. It's no worse than their source for testing the idea of an ancient Chinese astronaut.

The bottom line is that it showed that the technology was there. I wasn't fascinated by the warfare aspect of it. It's the SF aspect that got me. If even people like Jules verne had not dismissed the idea of traveling on rockets, who knows where we might be today.

You learned this from Dale, didn't you?

No, it was a much more personal and interactive lesson -- but yes, Dale was the proximate cause, or better put, the trigger.

throwing chainsaws into volcanoes is fine. Just use a launcher.

Yep, but that's now launching, now throwing, and I stand by my statement.

And make sure you know what the alloy of the body is.

We knew that, at least, within a very small range of alloys. What we didn't know was how fast it would sink.

Yup, ajay. Liquified laughing gas.

Too expensive, given the cost of LOX nowadays, but a perfectly useful oxidizer. Space Ship One basically flew on this and superballs, ok, hydroxy-terminated polybutadiene. Easier to handle than LOX (though we're pretty good with LOX) -- several high-power model rocket engines are N20/PVC or N20/HTPB powered.

Home Guard: Old men and boys armed with peashooters and ancient shotguns is the usual image, but like most odd images, only accurate for the extremes. Most of them were men of military age in reserved occupations, like agriculture. The almost unarmed period only lasted a few months in 1940. By August of that year most had military rifles, though these were often in the obsolete .300 calibre, and the real problem was ammunition. They even had some artillery, though again it was obsolete - French 75's. Again the problem was ancillary - ammunition and haulage. By 1941 the Home Guard was a force of real military value.

The weird devices were largely legend, though they existed at least in prototype. Great minds seem to have been most exercised as to how to stop tanks, and the Blacker Bombard, the various molotov hurlers and the sticky bomb were all attempts to address this. It had not yet been shown that deep penetration by armoured forces is not nearly so deadly as some thought it was, provided it was met by resolute infantry in suitable positions, capable of all-round defence, and backed up with guns firing both shot and shell.

I ran across a book years ago -- and unfortunately remember neither title or author -- that gave the history of two regiments of Home Guard who received quite serious irregular-warfare training, and were given actual military weapons. Both units had conventional Home Guard designations, and were assumed by their neighbors to be like any other unit, but their actual status was a military secret; the author, decades after the war, had to get a document from the War Office authorizing the surviving members to tell their stories before he could get a single one to admit a thing. (He'd originally run across some declassified documents while researching something else.)

There's an account in the book of an exercise in which a tank company crossed a field, the crews wearing smoked goggles to simulate a night action, and the Guardsmen slipped out of the foliage, applied their magnetic mines, and went back to cover. The crews saw and heard nothing, and the observers concluded that the "Germans" would have lost every vehicle. (I can't recall now if there were infantry supporting the tanks, which would almost certainly have been the real case, unless this action were being directed by Col. Klink.)

More immediately on topic, in addition to a quantity of time pencils* and other soundy-furious stuff, they had a handbook of IEDs** and other boobytraps, with a cover identifying it as The English Country Gentleman's Farm & Garden Handbook for 1939.

*Self-contained mechanical time fuze. Never popular on movie bombs, because it doesn't have a large display showing everybody how long it has left before the bang.
**Insert comment about underinformed American spokesmen here.

JMF: ...with a cover identifying it as The English Country Gentleman's Farm & Garden Handbook for 1939.

That's just great. I am SO Googling for that title RIGHT NOW.

Well, no sign of it in my usual haunts, but it's certainly one worth adding to the list.

It's Turtledove meets Wodehouse....

Bob: I may not have the title precise, but that was the gist -- it was supposed to look (and did) like the sort of thing anyone might have lying around the garden shed.

I used to recall the unit numbers, but won't post approximate guesses. If I find anything else, I'll put it up.

Thanks. I so need that book on my coffeetable.

I suddenly have an idea for a new CafePress product -- fake book covers/dust jackets.

Yes, I know it's not an original idea.

On the subject of WWII improvised munitions, my favourite must be the Explosive Rat.

Sorry. Key point about the explosion ship: after lighting the fuse, the crew get into a small boat and row away, very fast indeed.

I suspect that the reason so many great minds focussed on stopping tanks was recent history. Remember, the French army wasn't really destroyed; it disintegrated, largely under the impact of what the Germans called 'panzer fright'. The Home Guard were largely ex-Great War, so they knew they could beat infantry; the main issue was making them confident enough that they wouldn't run as soon as the first tank appeared.
For a well-written and light-hearted look at this whole period, I recommend 'Invasion 1940' by Peter Fleming (brother of Ian). The chapter on British preparation for invasion has the epigraph "Well, one can't eat cucumber sandwiches in an agitated manner."

Turtledove meets Wodehouse

Now THERE's an idea.

Um...Bob? Might I suggest that trying to lay hands on a book that contains instructions for IEDs, however obsolete, might not be the best thing just at the (political) moment? Just a caution in case you hadn't thought about it.

Xopher: but that's exactly what makes owning The English Country Gentleman's Farm & Garden Handbook for 1939 (or whatever it's called) so appealing.

I mean, everybody has their copy of Anarchist's Cookbook lying around. This would be a bit more subtle.

Ah. French 75's. The cannon and the drink. . .

It turns out that everyone else has been drinking different things than me and calling them French 75's.

(My version is Champagne and cognac; as it was explained to me, they come from the same grapes and it's not mixing. Everything on the internet seems to say "Gin and champagne." Yuk.)

As far as "Shrapnel" I was under the impression that the world needed a word for "white-hot chunks of shell casing in action" and shrapnel was adopted, regardless of original meaning. It's been used that way for a long time- Ernie Pyle used it in WW2, I know.

This would be a bit more subtle.

And probably less likely to end up costing an arm and a leg (of the literal variety).

Sorry. Every time I see a reference to the Anarchists Cookbook I cringe.

I know where to go right now today to put my hands on a whole lot of Army field manuals on improvised explosives, booby traps, and much else. You can pay cash, no questions asked.

The Anarchist's Cookbook: About one third of the recipes would work as advertised. About one third won't do anything at all. About one third are so wrong that they'll kill anyone who tries. I always figured it was an attempt by someone to thin the ranks of the Weather Underground by getting them to blow their own heads off.

John M. Ford: I remember something in the UK papers a while back (a year or so?), in which home guard members that had been picked to form the core of a guerilla force in the case of a successful German invasion were interviewed - I believe the information had just been declassified. They were trained in some of the particularly nasty aspects of irregular warfare. Apparently there are still hidden dugouts strewn across the English countryside that are not marked on any maps. Some of the home guard's training manuals were particularly bloodthirsty, much more so than the regular army's - Joanna Bourke comments on this in her 'Intimate History of Killing'.

I always liked Hoppity Hooper, if for no other reason than the adventure with the Atomic-Powered Corkscrew. (The scene featuring the reactor being installed was a black screen while, as I remember it, a voice over intoned "We're General Atomic. We don't have to tell you anything.") Then again, I was attacked as a racist bastard for admitting in a Usenet newsgroup that I'd liked Calvin and the Colonel when I was little, so what do I know...

I knew a guy in college whose high-school Chemestry class had progressed to guncotten (Thank you, Mr. Verne!) when they had to close things down: one of the class idiots decided to revisit earlier glories and made a FOUR POUND block of NI3. He wanted to play with it in private, so he decided to put it above his sweater and under his nylon windbreaker and walk home. Yes, it did just what you think it did.

A friend who is an electrical engineer built me a Theremin, and an Electric Pickle which I'm delighted to own, but drew the line at a Jacob's Pickle like Teller's. Sometimes my friend is so stodgy.

Margaret's Pneumatic PVC Cannon was pretty easy to make once I found a deranged Texan who had spent several thousand dollars making a PVC pipe rifling machine. Hey, gotta have accuracy with root vegetables.

What I want is a Mattel Agent Zero M Sonic Blaster 5530. In the words of Consumer Reports it "fires compressed air with a deafening blast. Our measurements top out at 157 dB--above a level that can do permanent damage to the hearing of an adult. We rate the toy Not Acceptable."

YAARRR!

Unfortunately, the Buy It Now price for one Mint In Box on eBay is US $2,499.00. Plus shipping. Which is why I've got Jordan's (Hi, Jordan!) Wham-O Air Blaster waiting to be repaired and possibly used to make some molds.

And on the subject of unstable pyrotechnic-type things: my father had a work buddy who was a pyrotechnics guy (they're both dead now, so don't ask). He told us about gold azide, which is less stable than lead azide; neither one is something you want at home, as they apparently tend to go bang if you look at them. I think he was also involved in things that turn night into day. (My father did things at work with safing and arming devices, as well as fuses and timers.)

Do you know what the penalty is for revealing the identity of a Mattel Zero M agent?

Neither do I, but we may be about to find out.

John M. Ford
Technical Consultant to Cobra Commander

I forgot to mention my uncle's science experiment. Uncle Phil worked at McDonnell Douglass. While he was there someone told him that Magnesium would burn under water, so he collected a five-pound coffee can of Magnesium chips, brought it home, and put it in the middle of his driveway. He then filled the can with water, making sure that a corner of one of the chips stuck out of the water, and splashed a tablespoon or two of gasoline on top of the water to act as a fuse for the magnesium. Then he lit off the gasoline.

He learned several things. First, that you'll end up with a column of flame almost a foot across and the better part of eight feet tall. Second, that the water will keep the can cool enough that the solder holding the can together won't melt. Third, that the can gets so hot that the blacktop under the can will melt and run down the driveway. Fourth, that when the L.A. fire department arrives they will have no sympathy to the argument that setting magnesium on fire in your own driveway is your own damn business.

Bruce Durocher wrote:
"I always liked Hoppity Hooper, if for no other reason than the adventure with the Atomic-Powered Corkscrew."

This reminds me of the superhero origin story I once read, wherein the scientist hero has invented the World's First Nuclear-Powered Motion Picture Projector. It was one of those government projects, so this naturally took place on a Secret Government Base, with armed troops protcting the research site, etc. Of course one of the Assistant Scientists was *actually* a Communist Spy, who sabotaged the NPMPP's first test.

In the ensuing explosion, the scientist-hero was badly injured. Heroic efforts by doctors (memorable dialogue: "May God forgive us for what we've done!") saved the scientist's life, but...

...but the scientist-hero ended up with a large radioactive film-reel deeply and permanently embedded in his forehead and brain.

As it turned out, though, the scientist now had the power to project images from his eyes, said images taking on corporeal form and fighting evil. (Sorta like Green Lantern's power ring.)

The scientist quickly took on a costume and a young sidekick, "Sprocket". But it was the story's introductory slogan that I best recall:

"At last! A hero who's a... REEL MAN!"

I remember one time I was with one of my pyromaniac friends whose favourite substance of the time was a mixture of sugar as fuel with sodium chlorate as an oxidiser[1]. One day he got adventurous and added some small clippings of magnesium ribbon to the mix. For some reason, he let it off _indoors_. This was not so ridiculous -- previous mixtures of this size hadn't done a huge amount.

I suspect there are charred marks on the ceiling to this day.

[1] Sodium Chlorate, when sold over the counter in the UK, always has a flame retardant added. It doesn't help.

Bruce E. Durocher II: While he was there someone told him that Magnesium would burn under water...

Back in college, some of my chums went through a Homemade Thermite phase.

Viewed from the tranquility of several decades later, I'm surprised that no one was killed.

In the words of Dr. Frankenstein's creation: "Fire. BURN."

you'll end up with a column of flame almost a foot across and the better part of eight feet tall

Doesn't have to be home-made: one year we had a (as in one only) firework for the Fourth. Aircraft flare. Set in a pile of sand on concrete slab. Lit the back yard very nicely. As a fountain, it was impressive. (No officials were disturbed in the process.)

Hey Teresa,
I just subscribed to MAKE magazine and it's absolutely brilliant! At least, I hope it will be, because it'll take 4-6 weeks to get to me (Iive in Australia) and I forgot to select digital Mag. Anyhow, I was wondering if you could post or send me the complete instructions on making Wizard Crackers because quite frankly, any moderately volatile object that can fool my sister into thinking it's a simple festive decoration, when in fact it's a clandestine ball of flame, is excellent and I'm sure my younger brother (an avid Harry Potter fan) will agree wholeheartedly. Hope you have a Merry Christmas (I've never had a white one...) and remeber, Santa Claus needs his beard to amuse little kids so don't leave any crackers lying around that might singe it off. Yours Truly, Jaymes Carr.

I just realised that I must be the only person on this page to have typed 'Yours Truly'. Damn.

Have any of you guys ever made traps instead of guns? Once I made a dart trap using low class gunpowder, a straw, a bamboo kabob stick, and some duct tape. Lets just say that not much is left to the imagination. Kuh thud