HARP Gun, microsatellite launcher

[Xantcha]

I'm trying to make simple addon project - basically it's a gun for launching microsatellites (it was closed before anything was actually launched into orbit, but overall it was interesting and looked like a possible thing).
Here is description of the thing, and there one can find lots of pictures (compared to what is on aeronautics). There is an article on wikipedia as well.


The initial idea was to model a Babylon project gun (Gerald Bull's late design, interesting man he was, btw) It was envisioned as 800 mm, 195 caliber - big impressive thing .
But there is too few pictures of it for my taste and description is rather vague. So I have choosen HARP's 16 inch L86 gun. As "ammo" I plan to use Marlet-4 rocket (for similar reasons - it's article on astronautics is more detailed .
Anyone aware of orbiter's microsatellite addons, that can find this usefull? Guess, I'll have to do one first then. Something like crystall bal with miniature of DG inside.

Not the best way to deliver large cargo into orbit but (if it was built as planned) most cheap, fast and "realizable". Plus I found the whole idea of "gun-boost" rather amusing - it's so old-style

Here are some pics:
* Overview

* horizontal position close-up

* Ready position close-up

Also - anyone knows how I should animate a cannon fire? I think after shot I have to move the whole thing down, like this:

but I'm not sure.. Also three tubes on top of gun confuse me - are they supposed to compress, and if yes, when?

Oh, and another thing - the tough physics part - how to calculate muzzle velocity for payloads of different mass? From data I have (speeds for payloads of 500, 1000, 1500 lbs) it looks mass like it is inversly proportional to cube of velocity. So say i'm increasing mass 9 times and velocity is 3 times less What better assumption I should use, or just limit payload between thos values and use interpolation?

 

[Xantcha]

Looks like no one yet is interested in space artillery.

Anyway, for me it's too late to stop, so I'll try to make the thing as good as I can. The gun is nearly finished, now so i'm working on marlet-4 now.

Finally added animations to gun, and started tinkering with particles. Not an excellent result but at least it is somewhat comparable:

Now I have to find some good BANG sound - making a gun that fires silently is pointless methinks
Any idea where i could find one?

 

[Andy44]

The tubes appear to be shock absorbers of some sort. On most modern field guns, there are tubes mounted on the gun which are filled with a fluid and which have a piston inside. When the gun recoils, the inertia of the piston forces it to resist the movement of the fluid, which absorbs some of the shock and keeps the gun from breaking off the carraige.

But the tubes in this picture appear to be connected at one end, so they must work differently. Also, a gun this big will require external bracing to keep the barrel from sagging as you elevate it. It seems to big for the usual shock absorber-type of recoil control.

BTW, I was wondering if you were interested in adopting some of your experience with space gun addons to developing a War of the Worlds Martian gun someday? If you've read the novel you know what I mean. The Martians launched their invasion of Earth from a giant gun forged in place in a hole in the ground, perhaps the caldera of a volcano. If I knew how to code a DLL for such a thing I would have made this add-on quite some time ago; the models would be easy enough.

 

[tl8]

Looks like no one yet is interested in space artillery.

Anyway, for me it's too late to stop, so I'll try to make the thing as good as I can. The gun is nearly finished, now so i'm working on marlet-4 now.

Finally added animations to gun, and started tinkering with particles. Not an excellent result but at least it is somewhat comparable:

Now I have to find some good BANG sound - making a gun that fires silently is pointless methinks
Any idea where i could find one?

Go to Global security and look through some video's for sount

 

[Chode]

Now I have to find some good BANG sound - making a gun that fires silently is pointless methinks
Any idea where i could find one?

The HBO movie "Doomsday Gun" is a very nice accounting (although semi-fictional) of the history (and demise) of Gerald Bull. For any fan of "ballistics-to-orbit", this is a must view. You might find some nice sounds for your project there.

Regards

 

[Xantcha]

2 CHode: thanks for the hint, I'll try to find it. Could be cool if addon used "autentic" sounds. Should I fail at obtaining the film, then I'll use some generic boom sound then. May be site suggested by tl8 can be a good place for that.

2 Andy44:
That will be a big project - there is little point in just hittting earth, some Earth-activity is a must. And this means a lot of meshes are required. Plus calculating necessary trajectory. making autopilot or navtools can be really hard. Besides, there is plenty of classics which I have never read. War and Peace is on such thing, War of the Worlds is another, so I'm mostly clueless about precise details.

Still it sounds like a fun thing addon - that's one-impulse transplanetary transfer after all. And with cool Earth activity in the end

And about that gun - what it was, Undergound steam gun with no visible barrel? And how much time it take for martians to deliver their canisters?

 

[Whatu]

Hey Xantcha, I remember seeing a documentary about this many years ago in Discovery Channel.. And now your making it, :speakcool:.
Looking forward to try it, and indeed it looks very cool, the particles look quite like the real photo...
Very nice :lol:

 

[Urwumpe]

About the shock absorbers... I recommend searching information about naval guns. The large guns on the Iowa class battleships have a very similar shock absorber layout as your gun, this might help you understanding, which part of the gun moves where.

I have no URL at my hands, was a while ago, I looked at it. The general idea behind I remember, was that the gun is made of multiple movable layers.

 

[Andy44]

2 Andy44:
That will be a big project - there is little point in just hittting earth, some Earth-activity is a must. And this means a lot of meshes are required. Plus calculating necessary trajectory. making autopilot or navtools can be really hard. Besides, there is plenty of classics which I have never read. War and Peace is on such thing, War of the Worlds is another, so I'm mostly clueless about precise details.

Still it sounds like a fun thing addon - that's one-impulse transplanetary transfer after all. And with cool Earth activity in the end

And about that gun - what it was, Undergound steam gun with no visible barrel? And how much time it take for martians to deliver their canisters?

Well, the beauty of it is that the reader never really finds out what the gun looks like on Mars. In the beginning of the novel, the characters are observing Mars through a telecope in England and they notice a bright light on the surface, which they deduce was the Martians pouring molten metal to forge the gun, and later I think they witness the muzzle flashes, followed sometime later (days or weeks, I think) by the invaders. That's it, so what the gun actually looks like is left to our imagination.

To get from Mars to Earth that fast would require enormous speeds and enormous decceleration upon arrival, but I don't think H.G. Wells had his interplanetary navigation well thought out, so we'd be forgiven for altering the transit times a bit, maybe.

Doing the canisters and emerging war machines shouldn't be too difficult with spacecraft3.dll, I think I could do it, and building the meshes would be fun, but the gun-launch system I don't understand.

As for navigation, If you put a vertical gun on the Martian equator, you can use the planet's rotation to control the right ascension angle of the launch, so there will be an optimal time each Martian day for a launch. Having an adjustable muzzle velocity and a canister with a modest propulsion system for course corrections and you should be able to find a set of good launch times, after launch you can use TransX for targeting and Aerobrake MFD to choose your landing site.

Just a thought, I'll shut up now and let you finish your curent project.