Things that make you go "Hmmmm…"

[Uncwilly]

Originally Posted by retina

They use 80286 CPUs. It won't even run P95 code, but it will control the entire aeroplane.

It might have to do with hardening. A friend of mine did programming for the space station's environmental system, way back in the day. This was back in the Space Station Alpha era. The work was on the boot up sequence and programming the EPROMs. The current processors were Pentiums. But they were programming a 80186.

The boot sequence for the environmental system had coding on reestablishing a environment compatible with life as rapidly as possible and dealing with the most important factors first. This was done assuming a hard start from an emergency loss of power.
First was dump nitrogen to get the pressure up to a certain level. Then when the pressure was in the ok range, deal with the oxygen. And so forth.

They were the first sub-sub-contractor to deliver actual working hardware that was to be used on the space station. (Or so I was told.) My understanding is that this did make it over into the ISIS, in a US module.

[xilman]

Originally Posted by Uncwilly

It might have to do with hardening.

It may also have something to do with the sound engineering dictum: if it aint broke, don't fix it.

A lot of elderly equipment is robust because it is simple --- of which your hardened criterion is an important special case.

A possibly extreme example is a fist-sized neolithic flint tool in my possession which has two sharp worked edges: an axe and a scraper. I still use it on occasion because it works as well now as when it was made a good few millennia ago.

[ewmayer]

Originally Posted by xilman

...a fist-sized neolithic flint tool in my possession which has two sharp worked edges: an axe and a scraper. I still use it on occasion because it works as well now as when it was made a good few millennia ago.

A splendid early example of a multitool - the Swiss Army Knife of its day! If it ever broke you could still throw it, and if the edges ever got damaged you could still use it to brain a foe. Using it as a firestarter alas would've required steel ... but maybe a chunk of meteoritic iron would've worked.

[xilman]

Originally Posted by ewmayer

A splendid early example of a multitool - the Swiss Army Knife of its day! If it ever broke you could still throw it, and if the edges ever got damaged you could still use it to brain a foe. Using it as a firestarter alas would've required steel ... but maybe a chunk of meteoritic iron would've worked.

Actually, it would be almost as easy to repair the edges as it is to resharpen a modern steel knife. You only need to know how to use pressure-flaking. I'm a rank amateur when it comes to flint-knapping. It's about time I started practicing again.

As for using it as a firelighter, I suspect you are very seriously wrong. Think about the physics of a modern cigarette lighter. A tiny flake of flint is abraded and heated to incandescence through friction with another harder and less brittle material. I may be wrong but I (presently) believe that flints were used to start fires long before the invention of steel.

Also apropos your comment, I had a letter published in The Times a couple years back in which the multi-tool aspect was the relevant issue.

[ewmayer]

Originally Posted by xilman

As for using it as a firelighter, I suspect you are very seriously wrong. Think about the physics of a modern cigarette lighter. A tiny flake of flint is abraded and heated to incandescence through friction with another harder and less brittle material. I may be wrong but I (presently) believe that flints were used to start fires long before the invention of steel.

Some backyard experimentation might be in order, though clearly you would want to use a non-Neolitihically-worked piece of flint for that. A pythonesque "That's not a cigarette lighter ... you're just bangin' 2 chunks of rock together" taunt comes to mind. The reply would be "well, we couldn't get a spark from banging the coconut halves together, so we switched to rocks."

[Brownfox]

Originally Posted by ewmayer

Some backyard experimentation might be in order, though clearly you would want to use a non-Neolitihically-worked piece of flint for that. A pythonesque "That's not a cigarette lighter ... you're just bangin' 2 chunks of rock together" taunt comes to mind. The reply would be "well, we couldn't get a spark from banging the coconut halves together, so we switched to rocks."

Some people who know about these things have suggested (https://www.primitiveways.com/marcas...d%20flint.html) that flint can be used to generate a spark using naturally occurring iron sulphides. I have a hazy recollection of this being used in the Clan of the Cave Bear fiction series. So you just need the right rocks.

[xilman]

Originally Posted by ewmayer

Some backyard experimentation might be in order, though clearly you would want to use a non-Neolitihically-worked piece of flint for that. A pythonesque "That's not a cigarette lighter ... you're just bangin' 2 chunks of rock together" taunt comes to mind. The reply would be "well, we couldn't get a spark from banging the coconut halves together, so we switched to rocks."

A good idea, which will have to wait for further testing until I return to the UK.

Young volcanic islands such as La Palma don't have much flint in them The mud of East Anglia is full of the stuff, so much so that it is used as a building material. In my garden, for instance, the average distance between flints exposed on the surface of the soil is about 10cm.

[ewmayer]

Originally Posted by xilman

Young volcanic islands such as La Palma don't have much flint in them.

Yes, I've heard that life in such locales for the aspiring fire-starting Neo-neolithitician can be quite tuff.

[kladner]

Originally Posted by xilman

Actually, it would be almost as easy to repair the edges as it is to resharpen a modern steel knife. You only need to know how to use pressure-flaking. I'm a rank amateur when it comes to flint-knapping. It's about time I started practicing again.

As for using it as a firelighter, I suspect you are very seriously wrong. Think about the physics of a modern cigarette lighter. A tiny flake of flint is abraded and heated to incandescence through friction with another harder and less brittle material. I may be wrong but I (presently) believe that flints were used to start fires long before the invention of steel.

Also apropos your comment, I had a letter published in The Times a couple years back in which the multi-tool aspect was the relevant issue.

I had the impression, perhaps wrong, that it is flakes of iron which are the sparks, at least in the outback fire-starting context. Perhaps the lighter uses a different principle?
http://survivaltopics.com/flint-and-...es-the-sparks/
(The web site above apparently protects itself from select-and-copy operations. I can't bring any text from the page over.)

EDIT: No, the passage pasted in twice after I had posted. Another Edit: I see now that the site added its copyright. I guess that explains the delays. This my first encounter with such a system, and I applaud it. I also note, with embarrassment, that I neglect the "QUOTE" tags in the end. .....Corrected!

How do you increase the rate of oxidization of iron? One way is to give a fresh un-oxidized piece of iron more surface area in contact with the air. More oxygen touching more iron will cause more oxidation which will give off more heat in a given amount of time. Increased oxidation can be accomplished by breaking off smaller particles of iron from a bigger piece. The smaller the iron particle is, the greater its surface area compared to its total size. Now you know the secret to using flint and steel to start a fire. Have you ever used a metal grinder or seen one in action on a piece of iron? Notice how thousands of glowing hot sparks fly off the wheel as it removes tiny bits of fresh iron off the chunk of iron being worked on. These tiny bits of iron are actually spontaneously catching on fire as they are exposed to the oxygen in the air.

Copyright © SurvivalTopics.com Read more at: http://survivaltopics.com/flint-and-...es-the-sparks/

[Dr Sardonicus]

Originally Posted by kladner

I had the impression, perhaps wrong, that it is flakes of iron which are the sparks, at least in the outback fire-starting context. Perhaps the lighter uses a different principle?
http://survivaltopics.com/flint-and-...es-the-sparks/
(The web site above apparently protects itself from select-and-copy operations. I can't bring any text from the page over.)

I can
:-D

I had to redo the formatting a bit, but hey -- no sweat.

In a nutshell the process of using a flint and steel to start a fire works like this:

• Find a piece of high carbon steel, which is about 98% iron and 2% carbon (a hard, relatively brittle steel).
  
• Find a piece of flint or other hard sharp object such as quartz.
  
• Strike a sharp edge of the flint a glancing blow with the high carbon steel. Doing this just right takes practice.
  
• Very tiny particles of fresh iron fly out from the steel.
  
• Upon contact with oxygen in the air, the surfaces of the iron particles spontaneously ignite and give off heat as they oxidize (rust).
  
• Because the surface area of the iron particles is so large compared to their volume, the particles quickly heat up and glow red hot. They become sparks.
  
• Catch the sparks in prepared tinder and use it to start a fire.

Best Flint and Steel

Iron by itself is relatively soft and tends to bend rather than chip under the stress of a hard blow on a piece of flint. To make iron harder for use in industry, it is made into what we call steel by adding some carbon. However by making it harder, the steel is also becomes more brittle.

The harder a piece of steel the smaller the pieces of iron broken from it will be when struck against a hard sharp object. As discussed earlier, smaller pieces of iron will spontaneously burn hotter due to their increased surface area.

Another way to get hotter sparks is to break off smaller pieces from the steel by striking it against a harder, sharper object. This is why you need to keep the edges of your flint very sharp for optimum creation of hot sparks when striking the steel.

In short, harder steel and sharper flints give better sparks.

Flint isn’t the only mineral that will cause sparks when steel is struck against it. Any hard stone with a sharp fracture can be utilized as long as it can break off very small pieces of steel.

Copyright © SurvivalTopics.com Read more at: http://survivaltopics.com/flint-and-...es-the-sparks/

BTW, an easy'n'fun way to see iron burn is to hang a piece of fine steel wool from a wire or something -- over a fireproof surface, I hasten to add. Then touch it off with a match or lighter. It doesn't produce so much flames, as an incandescent glow that spreads along the strands in an interesting manner.

[Spherical Cow]

Originally Posted by ewmayer

Yes, I've heard that life in such locales for the aspiring fire-starting Neo-neolithitician can be quite tuff.

aargggghh. Worst geologic pun ever. I salute you.