
The Tragic Tale of Saddam Hussein's “Supergun” - rm_-rf_slash
http://www.bbc.com/future/story/20160317-the-man-who-tried-to-make-a-supergun-for-saddam-hussein
======
pascalmemories
Oddly, the article fails to mention the UK government attempt to railroad into
prison the directors of the UK company asked to make the pipe components, by
covering up the fact they had approved the export using 'public interest
immunity' certificates to hide evidence from the courts.

[https://en.wikipedia.org/wiki/Arms-to-
Iraq](https://en.wikipedia.org/wiki/Arms-to-Iraq)

~~~
tonmoy
BBC is really a great source of unbiased new when UK is not involved in the
story.

~~~
beeboop
That's like saying RT.com is unbiased when it doesn't involve Russia, which is
very much not the case.

~~~
sydneysider
I'd disagree, along with Al Jazeera, RT is one of my staple news sources.

~~~
pizza
[https://www.rt.com/news/321121-lesin-dies-heart-
attack/](https://www.rt.com/news/321121-lesin-dies-heart-attack/)

Now I'm not saying nothin' bout RT in general, but this particular story isn't
exactly non-problematic...

~~~
tamana
That's a story about Russia

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nkurz
_A powder gun like the one used in Harp and a gas gun like Sharp both work in
the same basic way – expanding gases. The lighter the gases molecular weight,
the faster it expands in air. Gunpowder has a molecular weight of 22, slightly
less than air at around 28, but ignited gunpowder is incredibly hot, so that’s
why it expands so quickly. The hydrogen used in gas guns, however, has a
molecular weight of two so expands extraordinarily quickly in air._

I couldn't understand from the article how the hydrogen was being used in a
"gas gun". Since pure hydrogen doesn't ignite, wouldn't we care about the
molecular weight of the oxidizer as well?

It turns out the "light gas" is important just for it's low molecular
molecular weight. It's never ignited, and one could substitute Helium for
Hydrogen if one wanted. The gas is a second stage in addition to, rather than
instead of the gunpowder. It's like a spring-air gun, but instead of spring
you use an explosive charge.

Here's Wikipedia: [https://en.wikipedia.org/wiki/Light-
gas_gun](https://en.wikipedia.org/wiki/Light-gas_gun)

And here's some PVC experimentation: [http://www.chrisfenton.com/2-stage-
light-gas-gun/](http://www.chrisfenton.com/2-stage-light-gas-gun/)

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brandonmenc
There was a great HBO movie from 1994 called "Doomsday Gun" about this.

[http://www.imdb.com/title/tt0109650](http://www.imdb.com/title/tt0109650)

~~~
teh_klev
I agree, I watched that a couple of years ago and very much enjoyed it.

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theklub
This reminds me of the huge pumpkin guns people make.
[https://www.punkinchunkin.com/registered-
machines.html](https://www.punkinchunkin.com/registered-machines.html)

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zaroth
I love the twist of submerging almost the entire barrel in the ocean, pretty
awesome to wrap your brain around how that could actually work out. It was
also really interesting to hear Hunter's thoughts that even if the physics all
works and launch costs could be cut 1/10th, how it would still be unworkable
for someone SpaceX to invest in the R&D alongside their reusable rockets.

~~~
maxander
It would be interesting to see a quantitative head-to-head comparison, but my
guess would be that once you have the technology to retrieve first-stage
rocket engines after launch space-guns aren't economical- the fuel used
lifting the engine itself may be expensive, but the energy losses from hitting
sea-level atmosphere at ~8km/h would have to be _astronomical_.

...As it were.

~~~
mrfusion
I disagree. With a rocket you have to lift all your fuel. With a space gun the
fuel stays on earth and only the payload goes to space.

Look up the rocket equation to see what a huge difference this makes.

~~~
maxander
Does it, though? I mean, I've played KSP, I know the rocket equation. But with
a space gun, your vehicle only winds up moving as fast as the propellant
pushing it out- so that mass of fuel (more explosive than fuel, I guess)
_still has to be accelerated_ to near-orbital speeds in order for the gun to
work.

~~~
pizza
What about a railgun or some similar accelerator prior to the first stage?

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jdeibele
Frederick Forsyth's "The Fist of God" is a good read and uses Gerald Bull and
his super gun as part of the plot.

~~~
VikingCoder
Shows up in Michael Flynn's "Firestar" series, as well. "The Boomer" is what
they call it, I think. It was in the side of a mountain in South America, and
it was filled with gas.

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B1FF_PSUVM
Someone needs to pillage Jules Verne's books for movies, so that news writers
know about them ...

There's at least two super-guns in them, both launching to space as described
(one of them "and beyond", it's a Moon shot).

[https://en.wikipedia.org/wiki/The_Begum%27s_Fortune](https://en.wikipedia.org/wiki/The_Begum%27s_Fortune)

[https://en.wikipedia.org/wiki/From_the_Earth_to_the_Moon](https://en.wikipedia.org/wiki/From_the_Earth_to_the_Moon)

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Pxtl
With all the talk of Musk's Hyperloop, now I'm curious if the barrel was
evacuated (if that's worth it).

Even though this wouldn't be appropriate for use for delicate satellites, I
wonder if this would be a critical piece of equipment for industrialized space
- raw materials like fuel and oxygen and structural materials. Unfortunately
full satellites would be a challenge since googling reveals that experiments
involving these things included 10,000 gees of acceleration.

~~~
comicjk
Evacuating the barrel wouldn't do much. It's nice to skip 150m of air
resistance, but when you emerge from the barrel, you still have 15 km to go.

~~~
nickff
The main problem with having an air-filled barrel is that when the projectile
is going faster than the speed of sound, it is compressing all the air in
front it, all the way to the end of the barrel. Once the air can no longer get
out of the way, it is along for the ride (until outside the confined spaces of
the barrel). Carrying 100m worth of air will heat up the barrel and projectile
(as the air is being compressed), as well as adding a great deal of friction.

~~~
arprocter
I'm not sure how/if it scales, but here's an article about different lengths
of 5.56mm barrels, with graphs of pressure and velocity:
[http://www.sadefensejournal.com/wp/?p=1093](http://www.sadefensejournal.com/wp/?p=1093)

In reference to the second graph on the page, mach 1 is apparently 1125.33 fps

Do we know if the space guns are rifled or smooth bore?

~~~
nickff
Smooth bore as far as I know. Even tank cannons are mostly smooth-bore these
days.

The problem with those graphs is that they are not optimizing propellant
quantity for each barrel length. Adding an axis for quantity of propellant
shows that you get diminishing returns to increasing barrel length and
propellant, but there is a limit to how much you can increase both without
increasing the barrel's thickness (as well as the firing mechanism's
strength).

You also have to remember that a gun will require > Mach 25 to get to orbit,
and air acts differently at that kind of speed (, and once past ~Mach 3).

~~~
arprocter
Thanks for the insight - I guess it doesn't scale!

Is there a reason the space gun would be at a 45 degree angle and not pointed
vertically? I know the reason rocket launches happen as close to the equator
as possible, but they still go straight upwards...

~~~
nickff
Rockets only go up for a little while; most of the propellant is used to build
up speed in the 'horizontal direction'. There have been some arguments that a
strictly vertically-firing rocket would be best for going outside of Earth
orbit, but the current strategy for all launches is to go up until outside the
thickest part of the atmosphere, then go horizontal, to build up to orbital
velocity.

~~~
arprocter
After reading about the end of of Project HARP - it seems like they intended
to use the gun to fire a rocket, and after a certain altitude the engine would
ignite to get into space.

~~~
nickff
Yes, and in the years since HARP, there have been a few rocket-assisted
projectiles developed (though none which have been intended for space
launch).[1]

I should also mention that unless the projectile was fired at or above escape
velocity (intended to leave the Earth's gravity well), it would require some
onboard propulsion to 'circularize' its orbit (and avoid crashing back into
the Earth on its first time around).

[1] [https://en.wikipedia.org/wiki/Rocket-
assisted_projectile](https://en.wikipedia.org/wiki/Rocket-assisted_projectile)

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at-fates-hands
I love the tone of the article. It struggles to assert that although the gun
could be used as a weapon, _it had more potential as something to launch a
satellite._

You would have to be pretty naive to think the Iraqi's, who always wanted to
be the dominant Persian Gulf state in the region, would actually use this for
its intended purpose and not weaponize it to intimidate its neighbors in the
region.

~~~
maxander
Guns, unlike satellite launchers, need to be aimed at enemies in order to be
useful- something hard to do if its built into a hill.

I mean, _of course_ the Iraqi military (like everyone else) thought about it
as a weapon first, but if I were Bull I'd have been happy to con them out of
spending the same money on more effective weapons.

~~~
stcredzero
Saddam Hussein was a big Sci-fi fan. I'd guess he knew it was supposed to be a
launcher first, and still went for it.

~~~
effie
> Saddam Hussein was a big Sci-fi fan.

That sounds so weird. Could you post a reference?

~~~
stcredzero
After the capture of his palaces/compounds, there was some media coverage of
his sci-fi cover art collection.

(Just google "saddam hussein sci-fi cover art")

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rdl
University of Washington's Ram Accelerator (RAMAC)
([https://en.wikipedia.org/wiki/Ram_accelerator](https://en.wikipedia.org/wiki/Ram_accelerator))
is what I think will ultimately win. It's basically a long tube with mixtures
of natural gas, designed to work like a ramjet.

