Impeller wedge against ground target

Jonathan_S wrote:

Lord Skimper wrote:A bubble sidewall might work on a planet, it is gravatic but likely would have less effect on the atmosphere, than someone shooting at the planet, or a wedge. Plus most of the atmosphere would be inside the bubble.

Book 2 - Honor of the Queen has something to say about that idea.

Honor of the Queen wrote:“I don’t think they could have turned Blackbird into any kind of real fortress,” Matthews said quickly. “Not unless they can generate a sidewall bubble around a moon eight thousand kilometers in diameter.” He looked questioningly at Honor, and she shook her head.
“No, Sir. Not even Manticore can work miracles yet,” she said dryly.

Admittedly that's a damn big moon; over twice the diameter of Earth's. But its still smaller that most habitable planets are likely to be. So if its a "miracle" to shield the moon its even less possible to throw a bubble sidewall around a planet.

To be fair, I don't think he means enclosing the planet with a bubble sidewall. I believe what he means is using a bubble sidewall in a way that makes it mimic a dome over a city, like on Grayson.

Problem is, that doesn't work either. It's not as powerful as a wedge, but it works the same way - it's a field with a *very* high gravity gradient. High enough to still bend or otherwise distort incoming laser/graser fire, as well as stopping anything physical from getting through.

That's fine as far as it goes, but it will *also* have serious effects on the atmosphere, or the ground if it comes anywhere near it, which it would have to if you want complete coverage. Generate it high enough that it doesn't affect the ground, and it ends up being useless, as you can send any attack through from the sides, *underneath* the sidewall.

Anybody ever wonder why the sidewalls on a ship are generated 10km from the broadsides of the ship? I would speculate that a bubble sidewall would need the same clearances. Not to mention, it's very name implies complete enclosure, not partial.

As for his comment about "most of the atmosphere would be inside the bubble", yeah, it would... for a very short while. The sidewall gravitic gradient would still be strong enough to destroy atmospheric molecules, or if not destroy, attract them to its gravity field, creating a vacuum in the enclosed area, except *very* close to the sidewall itself.

OTOH, if he *did* mean enclosing the entire planet... well, you've already taken care of that.

I see three problems with this idea.
1) We have never seen an Impellar wedge of the right size (100 meters across)

2) It may not be possible to get it working in an atmosphere, I think there are some sort of limits on how close a wedge of a given size can be operated in an atmosphere

3) There's the issue of the rest of the planet exploding, remember when Harkness made Randsom's BC blow up the BC was a lot bigger then the pinace he had bring up the wedge

SCC wrote:I see three problems with this idea.
1) We have never seen an Impellar wedge of the right size (100 meters across)

Although size is never mentioned, there are two instances where we've seen smallish surface to air missiles used to take out targets. I would guess that the wedge size for those are *at most* 100 meters across, but most likely it's somewhat smaller.

SCC wrote:2) It may not be possible to get it working in an atmosphere, I think there are some sort of limits on how close a wedge of a given size can be operated in an atmosphere

Oh, a wedge can definitely work in an atmosphere. It's just that there are *so* many problems when you do. Even on a pinnace, disregarding the size of the wedge (over 10km on a side, most likely), there's also the issue of how far the wedge is from the pinnace. The center of each wedge plane is probably going to be somewhere around 2-3km away from the pinnace, which would place the leading edges at around 4km above *and* below the plane of the pinnace.

Safety (all other considerations aside) would require that a pinnace approach no closer than 6-7km from the surface. Any closer than that, and you start tearing up rocks, dirt, trees, people, buildings, near-dogs and pseudo-cats, mountains, and so on.

SCC wrote:3) There's the issue of the rest of the planet exploding, remember when Harkness made Randsom's BC blow up the BC was a lot bigger then the pinace he had bring up the wedge

That would only happen if the wedge was lit up underground, and even then, I doubt it would tear the planet to shreds like that. The largest wedges are those attached to SDs and they're only 300km on a side. A livable planet would be roughly 10,000km diameter or so. That's a big difference in ratio from that of a pinnace wedge inside a BC - the pinnace wedge is still *larger* than the size of the BC, whereas in the planetary scenario, the *planet* is orders of magnitude larger than the wedge.

Hi MaxxQ,

Kudos.

Quite right.

Although a couple of slight nits; 8000 km is more than 2.3 times the moon's diameter of less than 3500km.

We have textev that some wedges or sails including the larger freighters are up to 500 km in radius.

Given the very limited textev on bubble sidewalls, fortresses are thus protected but just how big bubble sidewalls can be is still speculative since HH's response seemed rather rhetorical to me, as in not even close to 8000 km.

OTOH, that was the limit 20 years ago and given what wonders RMN R&D have created, what might they have come up for fortress sidewalls?

Then again if the Lenny Det's are around 20 MT, could they have much more powerful bubble sidewalls, in lieu of traditional wedge based sidewalls?

L

MaxxQ wrote:

Jonathan_S wrote:**quote="Lord Skimper"**
A bubble sidewall might work on a planet, it is gravatic but likely would have less effect on the atmosphere, than someone shooting at the planet, or a wedge. Plus most of the atmosphere would be inside the bubble.

Book 2 - Honor of the Queen has something to say about that idea.

Honor of the Queen wrote:“I don’t think they could have turned Blackbird into any kind of real fortress,” Matthews said quickly. “Not unless they can generate a sidewall bubble around a moon eight thousand kilometers in diameter.” He looked questioningly at Honor, and she shook her head.
“No, Sir. Not even Manticore can work miracles yet,” she said dryly.

Admittedly that's a damn big moon; over twice the diameter of Earth's. But its still smaller that most habitable planets are likely to be. So if its a "miracle" to shield the moon its even less possible to throw a bubble sidewall around a planet. **quote**

To be fair, I don't think he means enclosing the planet with a bubble sidewall. I believe what he means is using a bubble sidewall in a way that makes it mimic a dome over a city, like on Grayson.

Problem is, that doesn't work either. It's not as powerful as a wedge, but it works the same way - it's a field with a *very* high gravity gradient. High enough to still bend or otherwise distort incoming laser/graser fire, as well as stopping anything physical from getting through.

That's fine as far as it goes, but it will *also* have serious effects on the atmosphere, or the ground if it comes anywhere near it, which it would have to if you want complete coverage. Generate it high enough that it doesn't affect the ground, and it ends up being useless, as you can send any attack through from the sides, *underneath* the sidewall.

Anybody ever wonder why the sidewalls on a ship are generated 10km from the broadsides of the ship? I would speculate that a bubble sidewall would need the same clearances. Not to mention, it's very name implies complete enclosure, not partial.

As for his comment about "most of the atmosphere would be inside the bubble", yeah, it would... for a very short while. The sidewall gravitic gradient would still be strong enough to destroy atmospheric molecules, or if not destroy, attract them to its gravity field, creating a vacuum in the enclosed area, except *very* close to the sidewall itself.

OTOH, if he *did* mean enclosing the entire planet... well, you've already taken care of that.

MaxxQ wrote:the *planet* is orders of magnitude larger than the wedge.

But the planet's crust is thinner than the size of the wedge (Earth 5 to 50 km).

MaxxQ wrote: SNIP for Brevity
There is no textev that indicates anything like this is possible. Of course, David is always free to add previously unmentioned research into this sort of defensive emplacement, but I kinda doubt he will.

Thank you for the break down. Spelling was always my worst subject D'OH!

So, it is completely illogical to do so. I wasnt sure, and had completely forgot the gravitaltional effects it would have. Oh, and I wasn't aware that you needed 2 on oppistie sides. I thought you could generate just one.
Thanks again.

MaxxQ wrote:Anybody ever wonder why the sidewalls on a ship are generated 10km from the broadsides of the ship? I would speculate that a bubble sidewall would need the same clearances. Not to mention, it's very name implies complete enclosure, not partial.

Yep, I've speculated that it's necessary standoff to be effective. We know that along with blocking or degrading energy hits the sidewall also deflects them. I'd guess the 10 km standoff is needed to allow beams that aren't 100% blocks to bend or diffuse to reduce their damage. But you have a good point that you probably also need a non-trivial safety clearance to keep the sidewalls' grav effects clear of the ship.


For old sidewalls the standoff distance doesn't affect tactics much (well a much larger distance would make the 'tunnel' formed by the sidewalls at the front or rear of the wedge wider; making down the throat or up the kilt shots easier. But for broadside shots, it could be 100 km out and I don't think, offhand, that would making it any easier or harder to target or hit the ship through it; it's still well inside the wedge's edge.


I started thinking about the standoff distance as a side effect of playing with the geometry of the new buckler sidewalls. It turns out that that 10 km standoff makes a big difference for them because it generates a much narrower 'cone' of protected angles than if they could work from 5 km away.


Enemies or laserheads within that notional cone can't hit your ship without first going through the buckler; enemies or missiles outside the cone can hit some of your ship without encountering any sidewall. Then, much wider out, they start encountering the ends of you side-sidewalls. So if you drew it you'd have an odd looking vulnerability map; much taller than it is wide.[1]


I don't have the numbers handy at the moment, but at "twice the maximum beam" you've got to be careful to stay pointed pretty much straight at your enemies, or they'd be positioned with clear line of sight (down the 'tunnel' formed by your side-sidewalls and past the edge of the buckler) to the mid-to-rear half of your ship's hull. *ouch*

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[1] I've occasionally thought about trying to make such a diagram. Learn to use a 3D modeling tool, model the ship, wedge, bucklers, and sidewalls; from say an 8-10,000 km out viewpoint. Use it to generate different colored zones showing where it's 1) protected by wedge; 2) by sidewall and armor; 3) by only one or the other; 4) unprotected.)

MaxxQ wrote:That would only happen if the wedge was lit up underground, and even then, I doubt it would tear the planet to shreds like that. The largest wedges are those attached to SDs and they're only 300km on a side. A livable planet would be roughly 10,000km diameter or so. That's a big difference in ratio from that of a pinnace wedge inside a BC - the pinnace wedge is still *larger* than the size of the BC, whereas in the planetary scenario, the *planet* is orders of magnitude larger than the wedge.

It wouldn't shred the planet, but even if the wedge only flashed for a few seconds and the crust is thin enough, there could be a volcanic eruption(provided the planet also has a liquid core), with a crater measuring tens or hundreds of kilometres in diameter. Definitely on the scale of the Yellowstone Supervolcano.

If the wedge is moving relative to the planetary surface, it's going to cut a trench. What if a wedge moving at a high velocity(.6-.8c) sideswiped a planet? Even if the ship didn't come close enough for the wedge to contact the ground, it'd still do quite nasty things to the atmosphere.

aairfccha wrote:

MaxxQ wrote:the *planet* is orders of magnitude larger than the wedge.

But the planet's crust is thinner than the size of the wedge (Earth 5 to 50 km).

Aaaand...?

As mentioned downthread, bringing up a wedge on or under a planet's surface will certainly have devastating effects, but what it *won't* do is make the planet explode. The ship would probably be destroyed before the wedge was up long enough to do more than create a rather large crater.

Don't forget that a wedge is open on the sides, although covered by sidewalls, and *completely* open on the ends. Debris and other stuff will still come rolling in and impact the ship. The only stuff to get destroyed will be in fairly close proximity to the wedge/sidewall planes themselves.

Earth has been impacted by much larger asteroids, and is still in one piece.

Commodore Oakius wrote:

MaxxQ wrote: SNIP for Brevity
There is no textev that indicates anything like this is possible. Of course, David is always free to add previously unmentioned research into this sort of defensive emplacement, but I kinda doubt he will.

Thank you for the break down. Spelling was always my worst subject D'OH!

So, it is completely illogical to do so. I wasnt sure, and had completely forgot the gravitaltional effects it would have. Oh, and I wasn't aware that you needed 2 on oppistie sides. I thought you could generate just one.
Thanks again.

Not a problem. Needing two planes only makes sense, since they are planes of gravity. Even if the gravitational force is weak at the distance a ship is from the plane, it's still going to be there. Having two balances that out.

As for me picking on your spelling error... I *am* somewhat of a grammar/spelling Nazi, but over the years, I've suppressed my urge to say anything about it... unless it can be made into something humorous, as yours was.

Jonathan_S wrote:

MaxxQ wrote:Anybody ever wonder why the sidewalls on a ship are generated 10km from the broadsides of the ship? I would speculate that a bubble sidewall would need the same clearances. Not to mention, it's very name implies complete enclosure, not partial.

Yep, I've speculated that it's necessary standoff to be effective. We know that along with blocking or degrading energy hits the sidewall also deflects them. I'd guess the 10 km standoff is needed to allow beams that aren't 100% blocks to bend or diffuse to reduce their damage. But you have a good point that you probably also need a non-trivial safety clearance to keep the sidewalls' grav effects clear of the ship.


For old sidewalls the standoff distance doesn't affect tactics much (well a much larger distance would make the 'tunnel' formed by the sidewalls at the front or rear of the wedge wider; making down the throat or up the kilt shots easier. But for broadside shots, it could be 100 km out and I don't think, offhand, that would making it any easier or harder to target or hit the ship through it; it's still well inside the wedge's edge.


I started thinking about the standoff distance as a side effect of playing with the geometry of the new buckler sidewalls. It turns out that that 10 km standoff makes a big difference for them because it generates a much narrower 'cone' of protected angles than if they could work from 5 km away.


Enemies or laserheads within that notional cone can't hit your ship without first going through the buckler; enemies or missiles outside the cone can hit some of your ship without encountering any sidewall. Then, much wider out, they start encountering the ends of you side-sidewalls. So if you drew it you'd have an odd looking vulnerability map; much taller than it is wide.[1]


I don't have the numbers handy at the moment, but at "twice the maximum beam" you've got to be careful to stay pointed pretty much straight at your enemies, or they'd be positioned with clear line of sight (down the 'tunnel' formed by your side-sidewalls and past the edge of the buckler) to the mid-to-rear half of your ship's hull. *ouch*

-----------------
[1] I've occasionally thought about trying to make such a diagram. Learn to use a 3D modeling tool, model the ship, wedge, bucklers, and sidewalls; from say an 8-10,000 km out viewpoint. Use it to generate different colored zones showing where it's 1) protected by wedge; 2) by sidewall and armor; 3) by only one or the other; 4) unprotected.)

Quoted the whole thing because I agree with it, but I'm only addressing your "fine print".

We've kinda/sorta done that at BuNine. The only difference is that my 3D model doesn't include bucklers. Not that that's difficult to add to the existing mesh. Andrew needed it to do some figuring for one of his talks at HonorCon last year, except he showed it from attack missile range.

munroburton wrote:

MaxxQ wrote:That would only happen if the wedge was lit up underground, and even then, I doubt it would tear the planet to shreds like that. The largest wedges are those attached to SDs and they're only 300km on a side. A livable planet would be roughly 10,000km diameter or so. That's a big difference in ratio from that of a pinnace wedge inside a BC - the pinnace wedge is still *larger* than the size of the BC, whereas in the planetary scenario, the *planet* is orders of magnitude larger than the wedge.

It wouldn't shred the planet, but even if the wedge only flashed for a few seconds and the crust is thin enough, there could be a volcanic eruption(provided the planet also has a liquid core), with a crater measuring tens or hundreds of kilometres in diameter. Definitely on the scale of the Yellowstone Supervolcano.

Yep. Disastrous, but *not* planet-exploding.

munroburton wrote:If the wedge is moving relative to the planetary surface, it's going to cut a trench. What if a wedge moving at a high velocity(.6-.8c) sideswiped a planet? Even if the ship didn't come close enough for the wedge to contact the ground, it'd still do quite nasty things to the atmosphere.

Aside from having nasty things done to the atmosphere, you gotta admit that it might be a way to do major contruction projects. Imagine how much easier it would be to carve a Suez or Panama canal...

Of course, if one has the technology to do that, one probably wouldn't absolutely *need* a Suez or Panama canal.

OTOH, we've seen people carving wood and ice with chainsaws, and using explosives to carve mountains... who's to say that some oddball artist 2000 years from now wouldn't be using spare moons or asteroids as his sculpting material, using a wedge to do the carving?

MaxxQ wrote:OTOH, we've seen people carving wood and ice with chainsaws, and using explosives to carve mountains... who's to say that some oddball artist 2000 years from now wouldn't be using spare moons or asteroids as his sculpting material, using a wedge to do the carving?

Hey art is art. Who are we to question, just no people on the moons, give a bad though to the idea of San Jus face on the moon over Nouvo Pari.
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