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Fall 1924: What will the Admiralty build next

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Re: Fall 1924: What will the Admiralty build next
Post by Somtaaw   » Sat Jun 25, 2022 9:32 pm

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Jonathan_S wrote:Did I? Guess I forgot. And it's a lot easier to remember the book quotes were they just give you the numbers.


Agreed, the book quotes are usually easier. Your calculations were done in the topic about Ghost Rider compensators (July 2016 actually), and your math came out with ~20000 gravs then too.

In another post in 2017, we got off-topic (like usual) about Eridani violations and were discussing Hermes buoys, and I again brought up the observed timers about Mobius, acceleration and the Hermes buoy being deployed at the exact moment the GR drones were decelerating to Mobius.

In ~2.5 hours a Hermess Buoy zipped ahead of Terekhov's makeshift squadron and made a close approach to the Solly destroyers in orbit of Mobius also undetected. But I don't think we have nearly enough information to figure their possible accel curve.

Here's what I can determine if you wanna take a pass:
-Terekhov's distance was again 215.9 million km, starting velocity was 913 KPS, and acceleration of 5.7 KPS squared.
-9 minutes later they're upwards of 4000 kps (not very exact I know), Sollies specifically mention
three hours and fourteen minutes to a zero/zero intercept with the planet…and us, of course. Turnover in about an hour and a half. Velocity at turnover will be right on thirty-five thousand KPS.


More datums for (trying to) calculate Hermes Buoy acceleration & stealth profile:
Quentin Saint-James had reentered normal-space twenty-six minutes earlier. During that time, she’d increased her n-space velocity to just over ninety-four hundred kilometers per second and traveled just under 7.8 million kilometers towards the planet officially designated Mobius Beta.


The Ghost Rider drones had to close from 96 light-seconds to 92 to detect the Solly ships, and Helen made her suggestion involving Hermes Buoys within approximately 5 minutes of that happening.

Terekhov regarded her thoughtfully for a moment, then nodded. “Works for me,” he said, and smiled at Pope. “And now that Ensign Zilwicki has so masterfully summarized her proposed approach, let’s give some thought to making it work most effectively.”


We don't know how long it took him to flesh out her summary and launch the Buoy, but it wasn't likely to be longer than approximately 15 minutes after the Ghost Riders hit that 92 light-second distance.

so our final datum is Terekhov was in-system approximately 26-30 minutes (how long would the Ghost Riders take to decelerate 4 light-seconds?), and then an unknown amount of time for Terekhov to quiz Helen, then plan and only Himself or Bu9 know how long it takes to actually kick a Hermes over the side and accelerating on its own drive. But let's assume he kept it brief, and overall he had the Hermes activating it's own drive after being in system for exactly 45 minutes?

Then for it to actually transmit
The (Manties)'d been in-system for almost two and a half hours now. In fact, they’d made their turnover and begun decelerating forty-eight minutes ago. The range was down to thirty-one million kilometers—under two light-minutes—and he’d started sweating the moment it dropped to forty million.


At some point prior to this, the Hermes buoy was already on station 40,000 km away from the Sollies and the ONLY reason they knew that was because it started broadcasting to them at that time. So it made the trip over I don't have the calculations for how many km's, in an absolute maximum of 105 minutes and stayed completely covert, although it probably made it faster.
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Re: Fall 1924: What will the Admiralty build next
Post by Jonathan_S   » Sat Jun 25, 2022 10:20 pm

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Somtaaw wrote:
Jonathan_S wrote:Did I? Guess I forgot. And it's a lot easier to remember the book quotes were they just give you the numbers.


Agreed, the book quotes are usually easier. Your calculations were done in the topic about Ghost Rider compensators (July 2016 actually), and your math came out with ~20000 gravs then too.

Hah! Good to know I'm (eventually) consistent.
But boy would it have been nice to have just saved that old spreadsheet. (But I probably did the same thing I did this time, which was to temporarily hack up my missile performance spreadsheet and then test and fit variations of acceleration and duration until the numbers made sense)

But this time I'm putting my results (if not all my calculations) into my missile survey sheet so hopefully I'll find it again if this comes up again in another 6 years :D
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Re: Fall 1924: What will the Admiralty build next
Post by ThinksMarkedly   » Sat Jun 25, 2022 10:27 pm

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Relax wrote:NIT: They would not be moving at half speed except at short ranges where you are understating how badly they actually would perform compared to a missile with 96,000G. In that aspect they would be WOEFULLY underperforming. Medium range is just blah at best. Due to FTL, ranges are going to blow up quite large. Also as we know we have ~23,500G in the tank for the RD, range to 0.8c is roughly 130Mkm. So, in between to sucks pathetically at short range. :P


The limitation in speed is not due to capability, it's stealth. The premise was "negating the CM basket," which would imply the ships being attacked cannot know where those drones are. But we know from TEiF that a drone carrying a missile travelling at 0.4c produces enough of a bowshock to be detectable. We don't know how much more detectable they are at double that speed, but it's not unreasonable to think it grows more than linearly with the speed and also grows roughly linearly with the time spent at high speeds, because faint detections accumulating over time would lead CIC to call it a real detection.

I think there's still scenarios where a Mistletoe or Silver Bullet, but it's not to attack an alert warship. Instead, I'd use them to sneak up on unsuspecting targets and decelerate to near zero relative velocity so they have time to orient a graser beam at the best angle.
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Re: Fall 1924: What will the Admiralty build next
Post by Somtaaw   » Sun Jun 26, 2022 12:20 am

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Jonathan_S wrote:
Somtaaw wrote:Agreed, the book quotes are usually easier. Your calculations were done in the topic about Ghost Rider compensators (July 2016 actually), and your math came out with ~20000 gravs then too.

Hah! Good to know I'm (eventually) consistent.
But boy would it have been nice to have just saved that old spreadsheet. (But I probably did the same thing I did this time, which was to temporarily hack up my missile performance spreadsheet and then test and fit variations of acceleration and duration until the numbers made sense)

But this time I'm putting my results (if not all my calculations) into my missile survey sheet so hopefully I'll find it again if this comes up again in another 6 years :D


I just searched the forum for Mobius + drone, because it's one of the best, if not only samples where we have known distances & velocities at several key intervals in the intercept, with all the factors we need to get a fairly good guesstimate.

Until the Ghost Rider drones get improved impellers, so we can figure by the time Honor comes out of retirement they'll be pushing 30,000 gravs if not 40 with both improved dwell time and even more ridiculous stealth.

inb4 Cthia can suggest tree-cat commandos with micro-rifles being inserted onto Darius Prime station via Ghost Rider drone that has so much stealth it actually got inside a shuttle bay? :lol:
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Re: Fall 1924: What will the Admiralty build next
Post by Jonathan_S   » Sun Jun 26, 2022 12:57 am

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Somtaaw wrote:In another post in 2017, we got off-topic (like usual) about Eridani violations and were discussing Hermes buoys, and I again brought up the observed timers about Mobius, acceleration and the Hermes buoy being deployed at the exact moment the GR drones were decelerating to Mobius.

In ~2.5 hours a Hermess Buoy zipped ahead of Terekhov's makeshift squadron and made a close approach to the Solly destroyers in orbit of Mobius also undetected. But I don't think we have nearly enough information to figure their possible accel curve.

Here's what I can determine if you wanna take a pass:
-Terekhov's distance was again 215.9 million km, starting velocity was 913 KPS, and acceleration of 5.7 KPS squared.
-9 minutes later they're upwards of 4000 kps (not very exact I know), Sollies specifically mention
three hours and fourteen minutes to a zero/zero intercept with the planet…and us, of course. Turnover in about an hour and a half. Velocity at turnover will be right on thirty-five thousand KPS.


More datums for (trying to) calculate Hermes Buoy acceleration & stealth profile:
Quentin Saint-James had reentered normal-space twenty-six minutes earlier. During that time, she’d increased her n-space velocity to just over ninety-four hundred kilometers per second and traveled just under 7.8 million kilometers towards the planet officially designated Mobius Beta.


The Ghost Rider drones had to close from 96 light-seconds to 92 to detect the Solly ships, and Helen made her suggestion involving Hermes Buoys within approximately 5 minutes of that happening.

Terekhov regarded her thoughtfully for a moment, then nodded. “Works for me,” he said, and smiled at Pope. “And now that Ensign Zilwicki has so masterfully summarized her proposed approach, let’s give some thought to making it work most effectively.”


We don't know how long it took him to flesh out her summary and launch the Buoy, but it wasn't likely to be longer than approximately 15 minutes after the Ghost Riders hit that 92 light-second distance.

so our final datum is Terekhov was in-system approximately 26-30 minutes (how long would the Ghost Riders take to decelerate 4 light-seconds?), and then an unknown amount of time for Terekhov to quiz Helen, then plan and only Himself or Bu9 know how long it takes to actually kick a Hermes over the side and accelerating on its own drive. But let's assume he kept it brief, and overall he had the Hermes activating it's own drive after being in system for exactly 45 minutes?

Then for it to actually transmit
The (Manties)'d been in-system for almost two and a half hours now. In fact, they’d made their turnover and begun decelerating forty-eight minutes ago. The range was down to thirty-one million kilometers—under two light-minutes—and he’d started sweating the moment it dropped to forty million.


At some point prior to this, the Hermes buoy was already on station 40,000 km away from the Sollies and the ONLY reason they knew that was because it started broadcasting to them at that time. So it made the trip over I don't have the calculations for how many km's, in an absolute maximum of 105 minutes and stayed completely covert, although it probably made it faster.

Well let's see what I can do.
tl;dr version: It seems it could have an accel around 825 gees.


Okay, first step is verifying the numbers on Terekhov are consistent and make sense. And they initially seem close enough; allowing for some rounding.

Time 0
* Initial velocity 913 KPS
* Acceleration 5.7 KPS squared (581.63 gees)
* Range 215.9 million km

Time 9 minutes (540s)
* up to ""just under four thousand KPS" -- from 913 KPS, 540s @ 581.63g = 3,991 KPS

Time 99 minute (5940s) [projected]
* Turnover at 90 min from T=9m, at "right on thirty-five thousand KPS" -- 5940s @ 581.63g = 34,771 KPS and 105,981,480 km

Time "almost two and a half hours"; 48 minutes (2880s) after turnover [if turnover was as projected this is 2h 27m (8820s) from emergence]
* "range was down to thirty-one million kilometers" -- from 34,771 KPS, 2880s @ -581.63g = 18,355 KPS and 182,482,920 km. 215,900,000 km total distance - 182,482,920 km = 33,417,080 km.
Not perfect but probably within a rounding error.

Time 3 hours 23 minutes (12180s) [projected]; 1h 44m (6240s) after turnover
* Zero/zero in 3h 14m from the same 9 minute mark -- from 34,771 KPS, 6240s @ -581.63g = -797 KPS and 211,980,360 km.

Not quite perfectly 0 KPS and 215,900,000 km; but presumably still within a rounding margin of error. (Actual zero velocity would be more like 6100s, 1h 41m 20s and that'd actually put them 55,720 km closer to the planet; as they wouldn't yet have started accelerating away again)


Problem is this bit in the middle
Shadow of Victory wrote:Quentin Saint-James had reentered normal-space twenty-six minutes earlier. During that time, she’d increased her n-space velocity to just over ninety-four hundred kilometers per second and traveled just under 7.8 million kilometers
Because, from 913 KPS, 26m (1560s) @ 581.63g gives you 9,805 KPS and 8,360,040 km.
Not 9,400 KPS and 7,800,000 km.

Still that's within the range of possibilities. He'd need to adjust acceleration at least twice within the 17 minutes between those observations; as there's no fixed accel that would hit both velocity and range given his known values at the 9 minute mark. And even going to no accel for a while and back to 581.63g won't so it. However one example that would is from the 9 to 10 minute mark drop to 0g accel, then from 10-26 minutes come up to 575 gees -- which would end up at said 26 minute mark with a velocity of 9,401 KPS and a distance of 7,752,048 km.

However if he's varying things up that much then we might as well throw the rest of the flight profile out; he could have turned over at a different time, increased acceleration to above 5.7 KPS^2, or anything else.


And we seemed to be doing so well. Ugh.

----

Still, that 26 minute fix is in the same scene as the Hermes buoy appears to be launched -- so let's take the dangerous approach of ignoring the inconsistencies and using its data for velocity and range at buoy launch.

We know he transmitted with the buoy at "less than forty thousand kilometers out!" from the SLN ships, and that at that point he's been in the system for "almost two and a half hours" and make "turnover [...] forty-eight minutes ago"; which we previously estimated was actually 2h 27m (8820s) from emergence.

So if we take those paragraphs both as true, and assume that the buoy decelerated to zero at that 40,000 km, and that it did so only just before the Manties transmitted then we'd have the following data points.
* Launch of Buoy T=0s
velocity 9,400 KPS, range 138,000,000 km from planet.
(215.9 million km upon emergence - 7.79 million km [just under 7.8] at launch)

* Arrived Buoy T=7,260s
velocity 0 KPS, range 40,000 km

And some fiddly trial and error later I've got a usable set of numbers. (Mind you, the precision is way beyond what I should use given how comparatively large the uncertainties in the starting numbers are).
If the buoy has an acceleration of 825.25g then it fits the above numbers.

From 9,400 KPS, 3048.853s @ 825.25g give us 34,057 KPS and 66,247,683 km downrange; and we turnover and accelerate for 4211.147s @ -825.25g which brings up down to 0.0054 KPS at 137,958,150 km downrange (or 41,850 km short of the planet where the SLN ships are)

---
But if he launched later, or the buoy arrived earlier, then all those numbers are off and we're back to having to guess how long he waited to launch (and what accelerations he adopted during that time; in order to get the new base velocity) and/or how much sooner it arrived. Either of those would produced a higher acceleration number.

Or if the buoy was flying by with a non-trivial remaining velocity then it could have had a lower acceleration.

Or hell, if for some reason it flew a variable acceleration path and/or didn't follow the least time route then all these numbers are totally out the window.
---

(Now, why did I just spend around 2 hours working on all this? :lol: )
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Re: Fall 1924: What will the Admiralty build next
Post by cthia   » Sun Jun 26, 2022 1:07 am

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Jonathan_S wrote:
Somtaaw wrote:Agreed, the book quotes are usually easier. Your calculations were done in the topic about Ghost Rider compensators (July 2016 actually), and your math came out with ~20000 gravs then too.

Hah! Good to know I'm (eventually) consistent.
But boy would it have been nice to have just saved that old spreadsheet. (But I probably did the same thing I did this time, which was to temporarily hack up my missile performance spreadsheet and then test and fit variations of acceleration and duration until the numbers made sense)

But this time I'm putting my results (if not all my calculations) into my missile survey sheet so hopefully I'll find it again if this comes up again in another 6 years :D


Somtaaw wrote:I just searched the forum for Mobius + drone, because it's one of the best, if not only samples where we have known distances & velocities at several key intervals in the intercept, with all the factors we need to get a fairly good guesstimate.

Until the Ghost Rider drones get improved impellers, so we can figure by the time Honor comes out of retirement they'll be pushing 30,000 gravs if not 40 with both improved dwell time and even more ridiculous stealth.

inb4 Cthia can suggest tree-cat commandos with micro-rifles being inserted onto Darius Prime station via Ghost Rider drone that has so much stealth it actually got inside a shuttle bay? :lol:

:lol:

Wait, you just might have something there! I have never understood humanity's need to put clothes on dogs and cats. It seems like such a restricting and inhumane punishment, except for the most dire of emergencies. Have you ever seen a cat or dog in an outfit? "Hey, get me out of this girdle!"

But that new smart cloth might have a certain appeal to a Treecat.

Son, your mother says I have to hang you. Personally I don't think this is a capital offense. But if I don't hang you, she's gonna hang me and frankly, I'm not the one in trouble. —cthia's father. Incident in ? Axiom of Common Sense
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Re: Fall 1924: What will the Admiralty build next
Post by Relax   » Sun Jun 26, 2022 1:09 am

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Jonathan_S wrote:And RD able to coast a warhead in a that kind of velocity would be moving so fast it's bow wake could be detected and and it's likely course swept by CMs.

Common man you know damned well you cannot vector CM's in that fast at that distance unless we go against what the books write. CM, assuming it is outside 'x' distance from ship and able to use its impeller has 130,000G for less than 3 seconds. That is essentially zero distance changed. That is a mere 8000km my man.

Now, here I have to disagree with the author and agree with you, and how he writes the books as I would have the CM's doing figure 8 loops right where you KNOW SDM/MDM have to be to shoot your ship(in layers of ~~ 10,000km out to ~300,000km and utterly forget midrange interception. Long range still is useful as you can fire more CM's/control interception).
_________
Tally Ho!
Relax
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Re: Fall 1924: What will the Admiralty build next
Post by Jonathan_S   » Sun Jun 26, 2022 1:23 am

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Relax wrote:
Jonathan_S wrote:And RD able to coast a warhead in a that kind of velocity would be moving so fast it's bow wake could be detected and and it's likely course swept by CMs.

Common man you know damned well you cannot vector CM's in that fast at that distance unless we go against what the books write. CM, assuming it is outside 'x' distance from ship and able to use its impeller has 130,000G for less than 3 seconds. That is essentially zero distance changed. That is a mere 8000km my man.

Now, here I have to disagree with the author and agree with you, and how he writes the books as I would have the CM's doing figure 8 loops right where you KNOW SDM/MDM have to be to shoot your ship(in layers of ~~ 10,000km out to ~300,000km and utterly forget midrange interception. Long range still is useful as you can fire more CM's/control interception).

I meant to say that it would be detected long before it reached that 300,000 km range; and so CMs could sweep its path out at the longer ranges they're more comfortable with.

Honor's Ghost Rider shell saw the bowshock the 0.4c Hasta armed drones generated while they were still far enough out to engage with CMs. I was simply saying that a 0.8c Ghost Rider could probably also be seen by a similar shell, or picket LACs, or whatever at that kind of further range.

(That's exactly why I went on to say that such a defense likely relies on having FTL equipped picket, whether drones, LACs, or whatever, around the fleet -- so you get enough warning for CMs)
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Re: Fall 1924: What will the Admiralty build next
Post by ThinksMarkedly   » Sun Jun 26, 2022 12:32 pm

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Jonathan_S wrote:Not quite perfectly 0 KPS and 215,900,000 km; but presumably still within a rounding margin of error. (Actual zero velocity would be more like 6100s, 1h 41m 20s and that'd actually put them 55,720 km closer to the planet; as they wouldn't yet have started accelerating away again)


Do note that zero-zero with the planet implies a non-zero velocity relative to the star. The planet is orbiting said star, so it has a velocity in the range of 25 to 40 km/s tangentially. The calculation for Earth is easy: 2*pi AU / 1 year = ~30 km/s on average (Kepler's first and second laws say it won't be constant).

The most likely approach scenario is that they aim to where the planet will be when they begin heading towards it. And in the two and a half hours of the transit time, the planet will have moved a bit too. So the trajectory is going to be a parabola too, with the ship's acceleration vector's direction changing over time.

However, the ships can accelerate to that in less than 6 seconds and the distance the planet will have moved is also negligible (268,000 km for Earth), so the errors in the calculations overwhelm any of this.
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Re: Fall 1924: What will the Admiralty build next
Post by Jonathan_S   » Sun Jun 26, 2022 1:53 pm

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ThinksMarkedly wrote:
Jonathan_S wrote:Not quite perfectly 0 KPS and 215,900,000 km; but presumably still within a rounding margin of error. (Actual zero velocity would be more like 6100s, 1h 41m 20s and that'd actually put them 55,720 km closer to the planet; as they wouldn't yet have started accelerating away again)


Do note that zero-zero with the planet implies a non-zero velocity relative to the star. The planet is orbiting said star, so it has a velocity in the range of 25 to 40 km/s tangentially. The calculation for Earth is easy: 2*pi AU / 1 year = ~30 km/s on average (Kepler's first and second laws say it won't be constant).

The most likely approach scenario is that they aim to where the planet will be when they begin heading towards it. And in the two and a half hours of the transit time, the planet will have moved a bit too. So the trajectory is going to be a parabola too, with the ship's acceleration vector's direction changing over time.

However, the ships can accelerate to that in less than 6 seconds and the distance the planet will have moved is also negligible (268,000 km for Earth), so the errors in the calculations overwhelm any of this.

Agreed. Absolutely right.

And because the effects of that motion and velocity are overwhelmed by errors inherent in uncertainty about the exact numbers used in the calculations it's not really worth the extra complexity of trying to account for -- not when dealing with things capable of hundreds or thousands of gravities covering many millions of km.
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