Re: Science of Pern
 

I'm pretty sure there are references to Bauxite (i.e. aluminium) in DDawn, as well as the rest of the rather limited mineral wealth of Pern.

As far as HNO3 goes, flamethrowers were developed in DDawn, but I'm not sure if they describe what chemicals were used in those ones or not. Although isn't that the first place we here HNO3 slurred into agenothree?

Re: Science of Pern
 

I don't think we hear "agenothree" in DDawn, but we do hear it in DE/RSR during the ground crews' flamethrower drill.

Re: Science of Pern
 

You do.

DD online:

Re: Science of Pern
 

If I am reading correctly, the books ALL imply that the HNO3 was not just sprayed as a mist/vapour (although it WAS used as a liquid in AWOP to erode the anti-matter engines) but was ignited to produce flame. HOW?

Re: Science of Pern
 

Okay, thanks Chi, that was the quote I remembered. Drat! Wrong book again!

Re: Science of Pern
 

Yep, that was the one I was thinking of as well. I first read -Dawn round about the same time as I started using HNO3 in chemistry, and the memories of those passages have stuck fairly well. Needless to say, it was way before RSR got published....

Re: Science of Pern
 

In RSR it's described as one of 2 liquids. It is an oxidising agent. But you'd need 2 tanks and it's pretty corrosive stuff so everything would have to be lined somehow, I did a diagram of fandarel's machine (which I need to re-draw) and I lined everything that came in contact with it with enamal- I'm assuming they had enamel or the metal tanks wouldn't last long- not would the pipes! But it all seems over-complicated if you look at other flame throwers which use a flamable liquid or gas (Mum's Organic Gardening magazine is full of them)

But fandarel's machine, which, despite the enthusiasm that was shown for it in DF sprays HNO3 directly on the Thread.

Re: Agenothree (HNO3, nitric acid)
 

There is conflicting information about what the flame-throwers really are: in some books they talk about a fine mist, in others it's definitely a flame. I seem to remember a six-meter flame at least mentioned in either DD or RSR. Probably DD just after they're so disappointed golds can't ingest firestone. Maybe someone with access to e-books could look it up?

There are other mentions of HNO3 being a great fertilizer, and this definitely implies a spray rather than a burn. Although I suppose thread ash could be a good fertilizer as well.

Re: Agenothree (HNO3, nitric acid)
 

as far as I can remember...
in DF they are trying to make a flamethrower but Fandarel comes up with a device that sprays HNO3 instead which impresses D'ram as it's a little bit safer.
In ATWOP theres a reference to it being nitric acid in the flame throwers
and in RSR there's a reference to 2 chemicals being used, one of which is nitric acid.

thats all I've got in my database but I may have missed something!

Re: Agenothree (HNO3, nitric acid)
 

Didn't the queen riders carry flame throwers as well? I could have sworn they carried them in the 9th Pass as well and shot out flame, not just spraying the chemical...

Re: Agenothree (HNO3, nitric acid)
 

Spiff, I was thinking the same thing while reading this. Queen riders do use flame throwers. And Edith is correct that D'ram thought the HNO3 sprayers were safer, they didn't have them in his time. So I'm thinking that eventually both were used.
Maybe HNO3 was used over crops and forested areas to help fertilize and keep the plantings safe. Flamethrowers by queen riders and also ground crews over rocky, weedy areas that could take a good burning.

Re: Agenothree (HNO3, nitric acid)
 

TWD online:

Selianth wants me to stay above her at all times so her flamethrower won't singe me, Ruth said, his mental tone muffled as he retained fire-breath. He altered his position and now all the wings began to move.

They had fire.

Re: Agenothree (HNO3, nitric acid)
 

That makes sense :D

Re: Agenothree (HNO3, nitric acid)
 

Just want to put in here, because the nitric acid/flamethrower issue is something I've run across in passing in my recent reading - I think Anne has confused the two different methods of Thread-destruction with each other.

HNO3, as I understand it, isn't flammable - it's corrosive. Fandarel's agenothree sprayer literally sprayed a mist of nitric acid to destroy Thread. The flamethrowers that the Oldtimers brought forward to the Ninth Pass used a flammable fuel to burn Thread either on the ground or from dragonback. But in the Second Weyr, when Torene is contemplating her flamethrower tanks, she muses that - "sometimes a fine spray was blown back before the HNO3 ignited". The same confusion between an acid sprayer and a flamethrower crops up in Moreta.

I'm not a scientist, so please do correct me if I'm barking totally up the wrong tree - but it looks to me like Anne has mixed up the two contraptions.

Re: Agenothree (HNO3, nitric acid)
 

oooh....
I just found this in Wikkipedia.

at http://en.wikipedia.org/wiki/Nitric_acid

Re: Agenothree (HNO3, nitric acid)
 

Nitric acid wouldn't burn on its own, but combined with another compound it would self-ignite, as Edith said. That would mean it'd be possible to use agenothree as a flamethrower fuel, but only by combining it with something else, such as turpentine.

Re: Agenothree (HNO3, nitric acid)
 

Okay...just dug up another HNO3 reference in RSR/D'Eye, when they're practising flaming "Thread" on the ground (actually ropes dropped over a cliff). There's talk of a mix of two gases being used to create the flame, which is different again to the Second Weyr reference, which speaks of a fine spray of HNO3 which ignites.

The Wiki reference is interesting, but since the Pernese were so anal about routinely calling the substance "HNO3" in the first place (when 'nitric' or just 'acid' would have been a more workaday term), wouldn't they have specified "the HNO3/turpentine mix" (or whatever) in the first place if it were a combination of two? Is turps good for crops? If, presumably, the two liquids have to be kept in separate tanks, why do we only ever heard about agenothree and never the other stuff? Why would you go out of your way to create what sounds like a potentially nasty sort of chemical reaction to make fire when a simple fuel/thrower combination would work just as well and require substantially less chemistry to manufacture the two substances?

Maybe I'm just a cynic, but I can't help thinking Anne didn't put that much thought into the science of agenothree/flamethrower mechanics...

Re: Agenothree (HNO3, nitric acid)
 

with regards to linings , Manora asks F'nor to take a lined numbweed pot to Smithhall because of discolouring of the numbweed and ask if its safe ( just before F'nor is wounded in a duel over a knife made for a wedding

Nick

Re: Agenothree (HNO3, nitric acid)
 

What, you're suggesting Anne didn't research and plot out the science in nitty-gritty detail in advance? Say it isn't so! :roll:

Re: Agenothree (HNO3, nitric acid)
 

I was thinking about this.
At first glance it does seem stupid, but on further reflection it makes sense to have a self-igniting flamethrower on dragonback at least.

Re: Agenothree (HNO3, nitric acid)
 

This is going a few years back so bear with me...

It was whilst I was studying my first year of HNC Science ( chemistry). I was speaking to one of my lecturers, just general chit-chat. The chap, a Dr. Nigel Freestone, is exceptionally smart, and something of an authority on transition metals...

Anyway, I asked him if nitirc acid was flammable, and got an unequivocal yes in reply. I explained why I'd asked the question, telling him about the Pern books and how HNO3 was used as a flame thrower fuel. He didn't contradict me, so I guess that agenothree is a suitable fuel

Re: Agenothree (HNO3, nitric acid)
 

Did you have a point to make there?

Re: Agenothree (HNO3, nitric acid)
 

Yes: each quote does indeed confirm that agenothree burns, which we were trying to prove.

Re: Agenothree (HNO3, nitric acid)
 

That's acid burn, corrosion - not combustion and flames, which is the burning currently under debate. There is no debate that HNO3 is nitric acid.

Re: Agenothree (HNO3, nitric acid)
 

Ooooooh. That makes sense. Thanks.

Re: Agenothree (HNO3, nitric acid)
 

A bit of Googling ("nitric acid + flammable") reveals that nitric acid itself is not flammable. A spray of the stuff wouldn't burst into flame. It is an oxidiser - that is, it contributes oxygen to reactions that include flammable or combustible materials.

It's highly corrosive to metals and organics, which fits with it being used as a corrosive rather than flame-based weapon against Thread - but they'd have to line the tanks with something non-reactive.

I'm not sure I'd want to be using it airborne with a dragon underneath me, though - the wind would surely blow the stuff back onto me and/or my dragon, which doesn't sound very pleasant.

Anyway, there's a PDF at http://click.ucdavis.edu/safety/Chem...ricAcidUse.pdf which describes the properties of nitric in detail - it's an interesting read when considering Pern's use of "agenothree"!

Re: Agenothree (HNO3, nitric acid)
 

I'd really like to know what they used.

It seems that the HNO3 won't work properly, since being a corrosive acid, if it were strong enough to eat Thread in the air, then it would be strong enough to do damage to its own tanks and to the humans and dragons using it.

Once the Thread is on the ground, a super-soaker would work just as well as the fertilizing agent.

As for a flamethrower, using some type of oil or fuel - flamable liquid - plus an 'ignition switch' would be good. A butane lighter comes to mind. Problem is - what happens if your flint is a bit low? Remember that story about the guy who bets that the kid's lighter won't light ten times in a row? Kid wins, he gets a Mercedes. Kid loses, he loses his pinkie finger.

I'm just wondering how the flamethrowers work - if there are times that you have a clump of thread in front of you, try to ignite your thrower, and nothing.

Re: Agenothree (HNO3, nitric acid)
 

Something I wonder about...

Moreta online:

...

How cumbersome is it? Isn't it kinda shaped like a trumpet?

Shalyn - as to a button to press, this might help:

moreta on.

Re: Agenothree (HNO3, nitric acid)
 

Shalyn. HNO3 doesn't corrode glass so lined tanks could be used. I did some work on this but I haven't posted it yet.

Re: Agenothree (HNO3, nitric acid)
 

OK - so the tanks would be fine. But what about the people and the dragons? That is, by using it in the air.

Re: Agenothree (HNO3, nitric acid)
 

There are probably some ceramic linings as well.

Re: Agenothree (HNO3, nitric acid)
 

I'm pretty sure I remember some mention of ceramic linings, somewhere...

Re: Agenothree (HNO3, nitric acid)
 

Maybe you meant this?

DQ online.

Re: Agenothree (HNO3, nitric acid)
 

Queens fly on the lowest level, you fly low and wear protective clothing-as they do!

Re: Agenothree (HNO3, nitric acid)
 

From the descriptions I've read about protective clothing, it protects the eyes, and most of the person. Faces are described as "windchapped", so they don't have anything on some parts of the face.

Dragons don't fly with goggles or protective clothing. So they are still not protected. Now, flamethrowers seem to be combersome, and I believe the nozzles are pointed down (which also seems idiotic - queenriders can't char Thread until it's past them? Seems inefficient.) But pointed down would work for agenothree sprayers - less chance of being hit by corrosive acid.

However, wind is a tricky little point of nature. The least little gust can have something going down come back up. So the dragon still isn't all that safe.

Plus, even protective clothing . . . I don't know. If I'm wearing anything that gets sprinkled or saturated with acid, I don't know that I still want to be wearing it. And if it gets sprinkled or hit over and over again . . . it still doesn't seem like a good way to fight Thread.

Re: Agenothree (HNO3, nitric acid)
 

It's not particulry. And the HNO3 sprayer was designed to be used on the ground wasn't it- as this was DF. How a flamethrower might work would be using the oxidising properties as a sort of lighter to light the flammable liquid, so, possibly, once there's a flame there doesn't have to be anymore used in that flame. I'll have to check though.

Re: Agenothree (HNO3, nitric acid)
 

can i suggest looking how a flamethrower from WW2 works?

Re: Agenothree (HNO3, nitric acid)
 

This may help...

M'reta online:

Re: Agenothree (HNO3, nitric acid)
 

I asked Nick how the Churchill Crocodile tank worked and that used a spark, he said that using an oxidising agent was dangerous, so whether that meant that something else used that system or whether he just thought it was rediculous, I'm not sure!

Re: Agenothree (HNO3, nitric acid)
 

None of the ones I've been able to find used hypergolic fuels (though NASA does for a lot of its rockets).

The early Italian ones used fuel oil + nitrogen as a propellant. the current U.S. ones use oil + benzine as both propellant and accelerant.

Old ones used anything from fuse cord to blank cartriges for the ignition (the U.S. Navy is known to have actually used Zippo lighters). Current ones use a bettery driven spark plug.

Tank (and boat) mounted ones were just much bigger but just as crude.

Try "lone sentry.com" & "howitworks.com".