Technical questions re military hardware.

Jonathan_S wrote:

MaxxQ wrote:OTOH, that is *exactly* how countermissiles work. Even though they are much smaller than regular missiles, their wedge is extremely overpowered in order to generate a wedge big enough to take out a missile. That's also why a CMs run-time is so short - the wedge is *so* overpowered, it burns out the nodes much quicker.

You say that, but at least by the Mk31 (Manticore's fairly new extended range CM for those of you who don't have all the missile designations memorized ) it's got the same 75 second run time as an Extended Range Missile running at full power; more than the 60 seconds of full power that single drive missiles had during the first war with Haven.

For a full power shot, it doesn't burn out quickly at all


I'm assuming though that CM drives can't be stepped down to 50% power for 3x endurance. (Otherwise with Viper dogfighting missile would outrange Havenite LAC missiles; instead of the other way round. But we were told it doesn't when we saw it first used against them).


Heck based on some number crunching I did a while ago I'm fairly sure that even as far back as HMS Fearless at Basilisk the CMs had a 60 second runtime; attack missiles only last longer because they're normally fired at 50% power.

Not quite correct.

The nodes of current generation Manty CMs have profited from the same general RMN R&D as brought us the Mk 14 shipkiller, the MDM and the improved beta nodes of the Shrike. That is, all of the nodes in question are tougher and have more endurance than their predecessors had, extending node life and/or power levels (but not both; endurance and power [i.e., accel] have always been a tradeoff), which explains the greater endurance of the Mk 31 and the Viper. CM missile nodes always have --- and still do --- burn out much more quickly than attack missile nodes built by the same technology, however, and the overpowered nature of their wedges mean that they can't be "stepped down" for extra endurance. Even at the most minimal level possible for the desired wedge strength, they are operating at too high a level to extend endurance significantly and, just as the shipkiller, the wedge can't be "throttled" after launch. Not that this means it can be throttled neither down nor up[/I. It can't be changed [I]at all, which means that several notions which have been proposed over the years are nonstarters. For instance, even if the power supply were available, and even if the nodes could (theoretically) stand the power levels required by the notion of "surging" wedge strength just before the missile reaches its target, it is literally impossible to alter the preset power levels/acceleration. Can't be done on something you can then fit into a missile body and produce the maximum accelerations you need for a practical weapon. You can stick a "scalable" set of nodes into a drone only because (a) maximum power levels are way lower and (b) there's more space for a more robust node and the necessary supporting hardware.

Shipkiller missiles (and their nodes) are very specialized pieces of hardware which are literally in a "self-destruct" mode from the moment of launch. They're designed for an operational regime in which simply turning them on is inevitably going to end in their destruction. At least as a live weapon of war; an "inert" missile at the end of its run could theoretically continue to drift as an intact hulk, were there not self-destruct features built into them to prevent them from becoming hazards to navigation (and any inhabitable planets in the vicinity.)

Everything I just said above about the shipkiller is true on steroids for the CM, however.

Wasted, cool it. be polite, or ignore him.

Jonathan_S wrote:

WLBjork wrote:Jonathan, it's worth rereading Storm from the Shadows, particularly the scene where Helen has to calculate the route.

Some grav waves limit you to the lower hyper bands - can't remember if RFC explained why.

There are also times when you need to travel more slowly to avoid the rogue waves, e.g The Selker Shear.

I remember it, though I believe the passage you're thinking of was actually in Shadows of Saganami (when Helen was asked the plot a least time course from the Lynx Terminus to the Spindle System). I had it in mind when I alluded to being forced to drop into a lower band (because of something like a rouge wave).

But the transit times compared to the velocity multipliers RFC gave us for each hyper band show that in this specific instance there isn't time for the ships to have had to go into a lower hyper band. They could barely make the stated transit times if they bee-lined straight there in the Theta bands at full speed. There's barely time for them to accelerate; much less to drop a band or two, come back up, and reaccelerate.


Though I'm still unclear why a warship in a hurry would ever want to follow a wave into a lower hyper band. Yes, avoiding a rouge wave might force you to. But Helen's example made no sense to me; least time courses pretty much mandate that you keep to the highest hyper band you can (to keep your velocity multiplier up) and that you deviate from the straight line path as little as practical. (Though at the beginning it can be worth following a grav wave a little out of the way where the 10x accel bonus outweighs the extra distance. But once up to cruising speed there's no speed advantage to being in a wave)

If there are areas to avoid then the routing gets more interesting. How big an area, does it extend to all bands, is it quicker the pay the energy losses and reduction in velocity multiplier to dive "under" in in lower bands and have to climb back - or to add lots of distance to go around in in your current band. But that didn't seem to be what Helen was calculating <shrug>

(And More than Honor had a background essay that included some historical limitations of sails; like having to tack when going "up wind"; but gave the impression those basically didn't apply anymore)

Now a warship on a long patrol might prioritize fuel over speed; so you'd make tradeoffs for following grav waves whenever that didn't overly delay you (where that's a bit of a subjective determination). But that wasn't the request in SoS - that was to plot a least time course.

Yeah I did mean Saganami, not sure how I got to Storm now. And another whoops for misinterpreting your point about faster travel, not slower travel.

Although for that I have an alternative: a neutral wormhole that can be used by DBs

runsforcelery wrote:

Jonathan_S wrote: ["MaxxQ"]
OTOH, that is *exactly* how countermissiles work. Even though they are much smaller than regular missiles, their wedge is extremely overpowered in order to generate a wedge big enough to take out a missile. That's also why a CMs run-time is so short - the wedge is *so* overpowered, it burns out the nodes much quicker.You say that, but at least by the Mk31 (Manticore's fairly new extended range CM for those of you who don't have all the missile designations memorized ) it's got the same 75 second run time as an Extended Range Missile running at full power; more than the 60 seconds of full power that single drive missiles had during the first war with Haven.

For a full power shot, it doesn't burn out quickly at all


I'm assuming though that CM drives can't be stepped down to 50% power for 3x endurance. (Otherwise with Viper dogfighting missile would outrange Havenite LAC missiles; instead of the other way round. But we were told it doesn't when we saw it first used against them).


Heck based on some number crunching I did a while ago I'm fairly sure that even as far back as HMS Fearless at Basilisk the CMs had a 60 second runtime; attack missiles only last longer because they're normally fired at 50% power.

Not quite correct.

The nodes of current generation Manty CMs have profited from the same general RMN R&D as brought us the Mk 14 shipkiller, the MDM and the improved beta nodes of the Shrike. That is, all of the nodes in question are tougher and have more endurance than their predecessors had, extending node life and/or power levels (but not both; endurance and power [i.e., accel] have always been a tradeoff), which explains the greater endurance of the Mk 31 and the Viper. CM missile nodes always have --- and still do --- burn out much more quickly than attack missile nodes built by the same technology, however, and the overpowered nature of their wedges mean that they can't be "stepped down" for extra endurance. Even at the most minimal level possible for the desired wedge strength, they are operating at too high a level to extend endurance significantly and, just as the shipkiller, the wedge can't be "throttled" after launch. Not that this means it can be throttled neither down nor up[/I. It can't be changed [I]at all, which means that several notions which have been proposed over the years are nonstarters. For instance, even if the power supply were available, and even if the nodes could (theoretically) stand the power levels required by the notion of "surging" wedge strength just before the missile reaches its target, it is literally impossible to alter the preset power levels/acceleration. Can't be done on something you can then fit into a missile body and produce the maximum accelerations you need for a practical weapon. You can stick a "scalable" set of nodes into a drone only because (a) maximum power levels are way lower and (b) there's more space for a more robust node and the necessary supporting hardware.

Shipkiller missiles (and their nodes) are very specialized pieces of hardware which are literally in a "self-destruct" mode from the moment of launch. They're designed for an operational regime in which simply turning them on is inevitably going to end in their destruction. At least as a live weapon of war; an "inert" missile at the end of its run could theoretically continue to drift as an intact hulk, were there not self-destruct features built into them to prevent them from becoming hazards to navigation (and any inhabitable planets in the vicinity.)

Everything I just said above about the shipkiller is true on steroids for the CM, however.

Oh, that is interesting. How about this; the missile uses the normal nodes for the run to the ship, but just before it reaches it (the last 30 seconds or so) those nodes go down and another set turns on. This set of nodes being overpowered that will burn out in a minute or less, but hit the ship's wedge a lot harder. I can see there being some technical problems though. Mainly getting a small enough power source in the missile to power the 'warhead' nodes. It might be a matter of trading some endurance for a much more powerful gravity warhead. With the current range though, I can see the idea being a nonstarter. Possibly useful, but not really feasible for now. More of a technical puzzle. If they were able to wreck the nodes of a ship, that traps it in the current system.

Although it might be a good weapon for raiders. Use it to blow merchant ship wedges without the risk of blowing the ship (maybe) that standard laser heads pose.

Another question, I've read about fusion and fission reactors (it was funny reading the Manticore reaction to fission nuclear reactors) and nuclear powered warheads, is antimatter used for anything or is it still more of a curiosity rather than a somewhat dangerous power source/explosive?

Zakharra wrote: Another question, I've read about fusion and fission reactors (it was funny reading the Manticore reaction to fission nuclear reactors) and nuclear powered warheads, is antimatter used for anything or is it still more of a curiosity rather than a somewhat dangerous power source/explosive?

As best I recall RFC mentioned some time back that antimater is still basically a lab curiosity in the Honorverse.

Oh and indecently you're preamble about the fusion and fission reactors reminded me of an interesting military tech tidbit. Unlike our current fusion weapons, which require a fission detonation in order to initiate the fusion reaction, Honorverse fusion warheads are pure fusion devices. They use a very short lived and very strong "burst" gravity pinch implosion to compress their fuel sufficiently to initiate fusion. And they also can use grav len projectors to "focus" the resulting nuclear blast; at least to a certain degree.

(The armor essay at the end of the In Fire Forged anthology goes into a lot of detail about the history of this)

Zakharra wrote:

Oh, that is interesting. How about this; the missile uses the normal nodes for the run to the ship, but just before it reaches it (the last 30 seconds or so) those nodes go down and another set turns on. This set of nodes being overpowered that will burn out in a minute or less, but hit the ship's wedge a lot harder. I can see there being some technical problems though. Mainly getting a small enough power source in the missile to power the 'warhead' nodes. It might be a matter of trading some endurance for a much more powerful gravity warhead. With the current range though, I can see the idea being a nonstarter. Possibly useful, but not really feasible for now. More of a technical puzzle. If they were able to wreck the nodes of a ship, that traps it in the current system.

Although it might be a good weapon for raiders. Use it to blow merchant ship wedges without the risk of blowing the ship (maybe) that standard laser heads pose.

Another question, I've read about fusion and fission reactors (it was funny reading the Manticore reaction to fission nuclear reactors) and nuclear powered warheads, is antimatter used for anything or is it still more of a curiosity rather than a somewhat dangerous power source/explosive?

That sounds like something that's been brought up before:

http://infodump.thefifthimperium.com/entry/Harrington/178/1

And it's a complete non-starter. There is no possible way with anything resembling current technology to put a drive into a missile powerful enough to fry a ship's wedge, except maybe while that wedge is only half-formed. Normally a missile wedge won't even burn out a warship's sidewall, let alone the wedge.

As for pirates using such a weapon, the last thing they'd want to do is fry their target's impeller drive. Much of the value of the haul is in the ship itself, which is in any case needed to carry the cargo away - no pirate ship (maybe 300k tons at most) can carry a worthwhile cargo, let alone the load of a 2.5M ton merchantman. Pirates need to take the ship intact enough that it can fly to a point where it can be sold on, or they're wasting their time.

Dafmeister wrote:

Zakharra wrote:

Oh, that is interesting. How about this; the missile uses the normal nodes for the run to the ship, but just before it reaches it (the last 30 seconds or so) those nodes go down and another set turns on. This set of nodes being overpowered that will burn out in a minute or less, but hit the ship's wedge a lot harder. I can see there being some technical problems though. Mainly getting a small enough power source in the missile to power the 'warhead' nodes. It might be a matter of trading some endurance for a much more powerful gravity warhead. With the current range though, I can see the idea being a nonstarter. Possibly useful, but not really feasible for now. More of a technical puzzle. If they were able to wreck the nodes of a ship, that traps it in the current system.

Although it might be a good weapon for raiders. Use it to blow merchant ship wedges without the risk of blowing the ship (maybe) that standard laser heads pose.

Another question, I've read about fusion and fission reactors (it was funny reading the Manticore reaction to fission nuclear reactors) and nuclear powered warheads, is antimatter used for anything or is it still more of a curiosity rather than a somewhat dangerous power source/explosive?

That sounds like something that's been brought up before:

http://infodump.thefifthimperium.com/entry/Harrington/178/1

And it's a complete non-starter. There is no possible way with anything resembling current technology to put a drive into a missile powerful enough to fry a ship's wedge, except maybe while that wedge is only half-formed. Normally a missile wedge won't even burn out a warship's sidewall, let alone the wedge.

As for pirates using such a weapon, the last thing they'd want to do is fry their target's impeller drive. Much of the value of the haul is in the ship itself, which is in any case needed to carry the cargo away - no pirate ship (maybe 300k tons at most) can carry a worthwhile cargo, let alone the load of a 2.5M ton merchantman. Pirates need to take the ship intact enough that it can fly to a point where it can be sold on, or they're wasting their time.

Ok. I was just throwing out an idea. The amount of information that this site has is mind boggling, so it's likely I have missed some things on the tech. It taking time to form a wedge makes sense and I can see why it would be more or less impossible to make something like that into a missile. Until they can find a way to turn a wedge on fast, it is a definite non-starter. Thanks for the find.

I wasn't thinking of pirates using them, but commerce raiders, like what the SLN CNO Fleet Admiral Kingsford wants to do with the GA. in that type of raiding, you don't want the ship to go back into enemy hands, so making it incapable of translating into hyper helps your cause (as long as you either remove the crew or don't care about them and just kill them after stripping the ship of anything useful and blowing the vessel.

hanuman wrote:Here is my next question, re dispatch boats.

I've just finished rereading Mission of Honor. After the Yawata Strike Mr Weber writes that the dispatch boat sent to recall Honor from Haven made the journey from Trevor's Star in only six and a half days, while the boat informing Manticore of the attack on Grayson's shipyards made the run between Yeltsin's Star and Manticore in four days.

Now why would that be, when the distance between Trevor's Star and Haven is several times the distance between Manticore and Yeltsin's Star?

I believe the statement that it takes 6 1/2 days for a dispatch boat to get from Trevor's Star to Haven is a mistake. We know that the distance from Manticore to Haven is around 300 light-years, and the distance from Manticore to Trevor's star is around 210 light-years, so the minimum distance between Trevor's star and Haven is 90 light-years. At the maximum speed of a dispatch boat, it would take 11 days for the trip--grav waves can't make it any faster than that.

Indeed, there is a reference (I believe in SVW) of a dispatch boat taking 11 days from Trevor's star to Haven.

SWM wrote:

hanuman wrote:Here is my next question, re dispatch boats.

I've just finished rereading Mission of Honor. After the Yawata Strike Mr Weber writes that the dispatch boat sent to recall Honor from Haven made the journey from Trevor's Star in only six and a half days, while the boat informing Manticore of the attack on Grayson's shipyards made the run between Yeltsin's Star and Manticore in four days.

Now why would that be, when the distance between Trevor's Star and Haven is several times the distance between Manticore and Yeltsin's Star?

I believe the statement that it takes 6 1/2 days for a dispatch boat to get from Trevor's Star to Haven is a mistake. We know that the distance from Manticore to Haven is around 300 light-years, and the distance from Manticore to Trevor's star is around 210 light-years, so the minimum distance between Trevor's star and Haven is 90 light-years. At the maximum speed of a dispatch boat, it would take 11 days for the trip--grav waves can't make it any faster than that.

Indeed, there is a reference (I believe in SVW) of a dispatch boat taking 11 days from Trevor's star to Haven.

You're probably right - SVW does state that "Haven was almost three hundred light-years from Manticore"; and I'd already seen that HoS had Trevor's Star at 210 ly from Manticore. (So I guess that does put Hera pretty much dead in line between them, since it's also a sum total of 90 ly from them.)

But SVW didn't have a courier from Haven to Trevor's Star (that I could find).

It had one from Haven to Barnett though (127 ly / 16 days); but that's well past Trevor's Star according to the wiki's maps (which admittedly aren't cannon). And that lines up nicely -- the straight 0.6c travel time for that distance is 15.5 days; leaving some time for acceleration, maneuvering, etc.



Just checked and it looks like 6.5 days for 90 ly is too fast even for a streak drive courier. (Best estimate is ~7.5 days transit time at 0.6c in the Kappa bands; ignoring detours or acceleration time). Definitely looking like an error that (understandably) made it past editing.

Mathematically, it could happen if RFC accidentally used the full velocity multiplier for the Theta bands; instead of 0.6 of it that a warship/courier can actually obtain. But I don't know if that's how the error actually slipped in.

Okay, I found my notes on distances mentioned in the text. Here is what we know about Manticore, Trevor's Star, and Haven.

The Short Victorious War:
"Haven was almost three hundred light-years from Manticore"

Flag in Exile
"Trevor's Star was over two hundred light-years from Manticore. It would take a superdreadnought over a month to make the hyperspace voyage between them"

War of Honor
"Basilisk, for example, was barely two hundred light-years from the Manticore System, while Trevor's Star and Gregor were both even closer than that."

War of Honor
"the dispatch boat took the better part of two weeks to get here [Haven] from Trevor's Star."

Mission of Honor
"Transit time [from Yeltsin to Manticore] was under four days for a dispatch boat, as compared to the roughly six and a half between the Junction's Trevor's Star terminus and the Haven System"

House of Steel:
"the Haven System lay over 250 light-years from the Manticore Binary System"

In addition, several of the maps mark the Manticore-Trevor's Star bridge as 210 light-years.

-----

Taking all this into account, I feel fairly sure that the "six and a half" days in MoH is an error. "The better part of two weeks" from WoH fits the numbers much better. However, House of Steel appears to significantly shrink the distance between Manticore and Haven. If that represents a remapping of the Honorverse, then 6 1/2 days might be possible.