the Destroyer future - a new take, with fission!

SharkHunter wrote:Known items. (1) Even back in HotQ the fusion reactors were kept operating while in the grav wave, so some power/bunkarage consumption was taking place -- but I'd think a fission core could manage it at fractional max-speeds in a given hyper band, and (2) what I am referring to as "afterburners" is really my way of saying that "maximum power" from a fission driven power plant isn't nearly enough" to accelerate and/or drive the ship under battle conditions.

(1) It is possible for a ship to completely turn off it's generator while running under sail in a grav wave. (2) Maximum power from a fission plant is not nearly enough to accelerate and/or drive a warship under non-battle conditions, too. Forget it--a fission generator is not enough for a destroyer.

Really the bigger issue is that the ship has to get to and outside the hyper limit with sufficient time to dropping back to .3C without getting trapped.

Ships almost never have to "drop back to .3C" because they almost never reach 0.3 c. To get up to .3c requires accelerating for much longer than crossing the entire sphere of the hyper limit.

SWM wrote:

SharkHunter wrote:Really the bigger issue is that the ship has to get to and outside the hyper limit with sufficient time to dropping back to .3C without getting trapped.

Ships almost never have to "drop back to .3C" because they almost never reach 0.3 c. To get up to .3c requires accelerating for much longer than crossing the entire sphere of the hyper limit.

Mmm, I wouldn't say "much" longer. At 5 km/s2 (~510 gee), going from 0 to 0.3c would take a ship 5.2 hours, during which it would cover 48 light-minutes. The diameter of a G0's hypersphere is 44 lt-min. And of course, there are faster ships and more massive stars.

Bill Woods wrote:Mmm, I wouldn't say "much" longer. At 5 km/s2 (~510 gee), going from 0 to 0.3c would take a ship 5.2 hours, during which it would cover 48 light-minutes. The diameter of a G0's hypersphere is 44 lt-min. And of course, there are faster ships and more massive stars.

But the point really is you are rarely dipping further in a system than 1/2 the radius of the Hyperlimit (1/4 the discussed diameter) because that is where the planets normally are.
Most attacks attempt a 0/0 intercept on a least time vector, so you only accel for 1/2 that anyway. As for the translation, the same decel usually happens in peacetime, as a lower translation speed is easier on the crew.

So unless you are really running for it, or are deliberately sneaking through the system the long way and doing a high speed flyby past the planet, You are rarely going to accel for more than 1/8 the hyperlimit diameter, and rarely hit .3c leaving a system - even a massive one.

Theemile wrote:

Bill Woods wrote:Mmm, I wouldn't say "much" longer. At 5 km/s2 (~510 gee), going from 0 to 0.3c would take a ship 5.2 hours, during which it would cover 48 light-minutes. The diameter of a G0's hypersphere is 44 lt-min. And of course, there are faster ships and more massive stars.

But the point really is you are rarely dipping further in a system than 1/2 the radius of the Hyperlimit (1/4 the discussed diameter) because that is where the planets normally are.
Most attacks attempt a 0/0 intercept on a least time vector, so you only accel for 1/2 that anyway. As for the translation, the same decel usually happens in peacetime, as a lower translation speed is easier on the crew.

So unless you are really running for it, or are deliberately sneaking through the system the long way and doing a high speed flyby past the planet, You are rarely going to accel for more than 1/8 the hyperlimit diameter, and rarely hit .3c leaving a system - even a massive one.

Sure, I was just nitpicking about the "much longer than crossing the entire sphere" thing.

Bill Woods wrote:

Theemile wrote: But the point really is you are rarely dipping further in a system than 1/2 the radius of the Hyperlimit (1/4 the discussed diameter) because that is where the planets normally are.
Most attacks attempt a 0/0 intercept on a least time vector, so you only accel for 1/2 that anyway. As for the translation, the same decel usually happens in peacetime, as a lower translation speed is easier on the crew.

So unless you are really running for it, or are deliberately sneaking through the system the long way and doing a high speed flyby past the planet, You are rarely going to accel for more than 1/8 the hyperlimit diameter, and rarely hit .3c leaving a system - even a massive one.

Sure, I was just nitpicking about the "much longer than crossing the entire sphere" thing.

Sorry Bill, I was trying to add to the point, not niting any statement in general.

SharkHunter wrote:Really the bigger issue is that the ship has to get to and outside the hyper limit with sufficient time to dropping back to .3C without getting trapped.

SWM wrote:Ships almost never have to "drop back to .3C" because they almost never reach 0.3 c. To get up to .3c requires accelerating for much longer than crossing the entire sphere of the hyper limit.

Bill Woods wrote:Mmm, I wouldn't say "much" longer. At 5 km/s2 (~510 gee), going from 0 to 0.3c would take a ship 5.2 hours, during which it would cover 48 light-minutes. The diameter of a G0's hypersphere is 44 lt-min. And of course, there are faster ships and more massive stars.

Maybe I'm missing something in my math, but dinking around with Excel using a 6km/sec accelerating ship, I got 4 hours plus a little, .3C, but at a distance of only around 10 LM. Granted, that's still Sol to somewhere between the Earth and Mars, but in theory Sol's hyper limit is at least double that. Slower speeds take longer to reach that rate, but the distance covered at the .3C point is similar, yes?

Most of the battles in the Honorverse took a lot longer to set up, RFC just condenses the actions down to the nitty-gritty when the ships are close enough (20 light seconds) to start throwing missiles at each other. AKA plenty of time to get past .3C and still be WELL within the hyper limit. That's why Honor set her attack plan against Thurston at maximum accel-- to disquise what she was coming with a a net result of still getting as far away from Grayson as that accel took them, but nowhere near Yeltsin's hyper limit.

Of course in the DDM and MDM age, fleets start throwing those missile salvos a lot earlier than they used to, which is where Manticore and Haven's (and every other star system's) ability to stage defenses in depth just got "thinned" by an order of magnitude.

Yes/no?

--snipping--

SWM wrote:(2) Maximum power from a fission plant is not nearly enough to accelerate and/or drive a warship under non-battle conditions, too. Forget it--a fission generator is not enough for a destroyer.

Gonna respectfully disagree for a simple reason: the fission plants in a LAC --which weighs around 20K tons is of necessity very tiny, but can provide sufficient power to push a Shrike et. al at +600G maximum accel.

I did specify that the ONLY mission I could see for a combined plant was for a long-duration scout that would spend much of it's time down in "putzing speed" ranges. It's like a ship version of a gazelle -- sits around most of the time watching for trouble but can outrun most predators if alerted.

So scale the fission plant up just by a size factor of 50% (1.5 cubed) would result in about 350% more power, downsizing the accel available to say a "merchie level" of 200K, and you're likely now close to pushing a ship the size of HMS Madrigal, maybe even with a "merchie like" single layer wedge.

Under any high accel circumstances, you absolutely need the multiplied and additive higher fusion plant output for the military wedge and to make a high-G getaway.

SharkHunter wrote:

SWM wrote:Ships almost never have to "drop back to .3C" because they almost never reach 0.3 c. To get up to .3c requires accelerating for much longer than crossing the entire sphere of the hyper limit.

Bill Woods wrote:Mmm, I wouldn't say "much" longer. At 5 km/s2 (~510 gee), going from 0 to 0.3c would take a ship 5.2 hours, during which it would cover 48 light-minutes. The diameter of a G0's hypersphere is 44 lt-min. And of course, there are faster ships and more massive stars.

Maybe I'm missing something in my math, but dinking around with Excel using a 6km/sec accelerating ship, I got 4 hours plus a little, .3C, but at a distance of only around 10 LM. Granted, that's still Sol to somewhere between the Earth and Mars, but in theory Sol's hyper limit is at least double that. Slower speeds take longer to reach that rate, but the distance covered at the .3C point is similar, yes?

I think you slipped up something in your math.

6 km/s works out to about 612g; fast but something many RMN ships can now do.
And 612g for 4 hours does give me about 0.288c top speed.
But I came up with the ship covering 621,831,168 km; or 35.5 LM.

Using Bill's 510g accel I got 5.1 hours to 0.306c, covering 842,386,910 km (46.8 LS) -- right in line with his calculation; if you allow for some rounding.


That's showing that reducing the accel lengthens both time & distance to achieve 0.3c. It seems to take an somewhat usual flight profile before you have to worry about the 0.3c speed limit to enter hyper (OTOH getting jumped while in transit to a wormhole terminus, or an out-system resource extraction node and a warship could easily have worked up to above 0.3c -- so it's hardly an unheard of situation)

SharkHunter wrote:--snipping--

SWM wrote:(2) Maximum power from a fission plant is not nearly enough to accelerate and/or drive a warship under non-battle conditions, too. Forget it--a fission generator is not enough for a destroyer.

Gonna respectfully disagree for a simple reason: the fission plants in a LAC --which weighs around 20K tons is of necessity very tiny, but can provide sufficient power to push a Shrike et. al at +600G maximum accel.

If you want to use logic, then look up how much hydrogen you need to fuse to helium to produce as much energy as 20,000 tons of Pu239.

Playing devils advocate: kzt, all RFC would have to do is invent a very very very very very very very very very very very very very very very very very ver yvery ver yvery vyevyeyeyvyyyyyyy DENSE material to fission.



Uh, pretty sure we do not know what material is being fissioned in those reactors.