Railgun

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Discussion

anonymous-user

Original Poster:

61 months

Saturday 27th January 2018
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Railgun tech is getting better, it just to be a lot more sustainable to use it to launch into space combined with a rocket, why no investments in this area.

Beati Dogu

9,193 posts

146 months

Saturday 27th January 2018
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There’s a lot of research money being spent on it as a weapon, especially by the US Navy for use as a replacement for the conventional gun. BAE Systems are working on it.

The acceleration is brutal, so nothing live would survive and anything else would need to be specially hardened as well. Perhaps on the moon it would be a viable way of getting some things off the surface, but I can’t see it being used on Earth for that anytime soon.

IIRC curious droid has a YouTube video about it.

Fugazi

564 posts

128 months

Saturday 27th January 2018
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A similar concept for orbital insertion are 'ram accelerators' which are basically cannons shooting a shaped projectile into a barrel full of oxygen and hydrogen. The projectile acts like a ramjet and compresses the gases via shock waves, then combusts the mixture behind it. It has the same issues as coilguns and railguns, in that the forces involved are huge and require things like electronics to be potted so that bits don't detach. I imagine the forces involved on solder joints during a trip from zero to Mach 8 over a few metres are going to strip boards of components. Also ram accelerators don't require huge electrical power and don't suffer from ablation due to the high temperatures generated by arcing. Incidentally I believe this concept was similar, if not the same as the Baghdad supergun.

I have wondered about how you would use them for orbital insertion as surely there must also be some kind of size limit imposed due to the forces involved and material stresses, so the thing doesn't start to deform or break apart during launch and I can't imagine something bigger than a Cubesat surviving intact. Unless you can control the initial accelerations. My thoughts are that if you're going to build one to launch into space, it's going to need to be a lot longer than a ship's main gun so you might be able to stage the power applied along the barrel length? Interesting concepts though.


anonymous-user

Original Poster:

61 months

Saturday 27th January 2018
quotequote all
the acceleration issue can be mitigated by making it a few miles long and building speed up,

Beati Dogu

9,193 posts

146 months

annodomini2

6,913 posts

258 months

Sunday 28th January 2018
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The problem with 'cannon' launch on earth is the muzzle velocity, LEO is mach 25. So due to air resistance you need to be going much faster than that at launch.

Launch altitude is critical and yet still, thermal will be a major problem, even if you launched it from the top of everest.

The other issue is that you must take a rocket to circularise your orbit and this all has to be able to cope with the stresses of launch.

Beati Dogu

9,193 posts

146 months

Tuesday 30th January 2018
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Should be doable. Even in WW2 they developed the valve-based 'VT' proximity fuses that were fired from all sorts of canons. Quite the secret weapon they turned out to be be too.

FourWheelDrift

89,640 posts

291 months

Wednesday 31st January 2018
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In 1966 Gerald Bull was firing objects into space, the 180kg Martlett 2 reached 590,000 ft a record to this day. If that had continued with proper funding I think he would have achieved a payload orbit, wouldn't have taken the Iraqi job and wouldn't be assassinated by Mossad.

Project HARP - https://en.wikipedia.org/wiki/Project_HARP

Beati Dogu

9,193 posts

146 months

Thursday 1st February 2018
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Pretty cool

Using a big gun to launch things into space has been an idea for a long time.

From 1902

https://www.youtube.com/watch?v=BNLZntSdyKE

annodomini2

6,913 posts

258 months

Thursday 1st February 2018
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FourWheelDrift said:
In 1966 Gerald Bull was firing objects into space, the 180kg Martlett 2 reached 590,000 ft a record to this day. If that had continued with proper funding I think he would have achieved a payload orbit, wouldn't have taken the Iraqi job and wouldn't be assassinated by Mossad.

Project HARP - https://en.wikipedia.org/wiki/Project_HARP
Space yes, orbit no.

2.1km/s is well shy of orbital velocity.

FourWheelDrift

89,640 posts

291 months

Thursday 1st February 2018
quotequote all
annodomini2 said:
FourWheelDrift said:
In 1966 Gerald Bull was firing objects into space, the 180kg Martlett 2 reached 590,000 ft a record to this day. If that had continued with proper funding I think he would have achieved a payload orbit, wouldn't have taken the Iraqi job and wouldn't be assassinated by Mossad.

Project HARP - https://en.wikipedia.org/wiki/Project_HARP
Space yes, orbit no.

2.1km/s is well shy of orbital velocity.
That was in 1966 do you think they wouldn't have improved in the following 50 years with proper funding?

annodomini2

6,913 posts

258 months

Friday 2nd February 2018
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FourWheelDrift said:
That was in 1966 do you think they wouldn't have improved in the following 50 years with proper funding?
See my previous post re Muzzle velocity.

FourWheelDrift

89,640 posts

291 months

Friday 2nd February 2018
quotequote all
annodomini2 said:
See my previous post re Muzzle velocity.
No problem if you are launching multi-stage rocket assisted projectiles.

AshVX220

5,933 posts

197 months

Friday 2nd February 2018
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Saw a post on a facebook group I'm in, a Chinese ship PLA Haiyang Shan has been spotted with what is thought to be a Railgun in place of the class's usual 37mm Gun. I expect that it's being used as a test bed, but apparently is the first ship to sail with one.

https://www.msn.com/en-gb/news/world/chinese-navy-...

anonymous-user

Original Poster:

61 months

Friday 2nd February 2018
quotequote all
they are amazing tech and once fired unstoppable. it is a shame no proper development as a payload carrier, add scram jet and earth rotation and i bet you could get anywhere on the planet.