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Honorverse ramblings and musings

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Re: Honorverse ramblings and musings
Post by Jonathan_S   » Wed Jul 19, 2017 6:32 pm

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Jonathan_S wrote:Presumably. And in exchange for greatly increased risk you'll get somewhat better performance.

(For simplicity I'm going to ignore acceleration time and in-system manouvering as they should be irrelevant to the variable of hyper generator safety - though Truman was probably also redlining her compensator which I should calculate as it affects total passage time)

Even so, unless acceleration has a much larger impact than I assume, I can't get the numbers to make sense for Truman's speed run back to Manticore in HotQ.

It's only 31 light-years between Manticore and Grayson so even a warship traveling sedately down in the Eta bands (2576 c) needs less than 106 hours at full speed make the hyper transit.
We're told turning off all the interlocks let the damaged light cruiser Apollo "cut thirty hours off the old passage record". But to cover that distance in even 76 hours you need 3575 c. Which is basically warship in Iota bands speed (3600 c), substantially better than we're told a warship can do in the Theta bands (3000 c).
So already seems implausible even if we assume the old passage record was made loafing around in Eta bands.


It we assume is was set in the Theta bands, where warships can go (and dispatch boats routinely utilize) the hyper passage time should be under 91 hours at full speed. Chopping that to 61 hours would require a multiplier of 4500 c; exceeding what a streak drive can do (Kappa bands - 4354 c)

So something seems is screwy in HotQ. But like I said redoing the full calc, assuming no compensator safety margin might clear that up. I'll see if I can find time with my spreadsheets to run that.

Okay, going back to my reference material and attempting to do the full calcuations.

Apollo started out at Blackbird, within Uriel's 5 LM hyper limit. As what I believe is an Apollo-class CL her standard 80% accel was 418.8 G.

And for all of these we assume the small grav wave we know lies near Grayson on the way to Manticore either is too far, or too low a band, to be helpful.

Normal leisurely transit
Assume warship stays at 80% accel and only uses Eta bands

Boost for 111 minutes at 80% accel gets you 5 LM out (and up to 27.034 km/s)
Jump up to the Eta bands drops your velocity to roughly of that 0.00431% - 1.1659 km/s
Then 738 minutes to 0.6c (12 hours 18 minutes)
Then another 5960 minutes (99 1/3 hours) at 0.6c to reach Manticore
Then dropping back to n-space drops Apollo's velocity to 7.75 km/s (but she can now radio for help; her trip is complete)

Total transit time 6809 minutes (113.48 hours)


Emergency transit w/ hyper generator interlocks in place
Boost for 100 minutes at 100% accel (517.8 gees) gets you 5 LM out (and up to 30,448 km/s)
Jump up to the Theta bands drops your velocity to roughly 0.00207% of that - 0.630 km/s.
Then 591 minutes to 0.6c (9 hours 51 minutes)
Then another 5139 minutes (85.6 hours) at 0.6c to reach Manticore
Then dropping back to n-space drops Apollo's velocity to 3.72 km/s (but she can now radio for help; her trip is complete)

Total transit time 5800 minutes (96.66 hours)

So a savings, over a leasurly cruise, of 16.82 hours just from the higher hyper band and the full accel. We just need another 13.18 hours from the generator safety interlocks. That would reduce the effective times c multiplier from the 3575 c calculated before to "only" 3547.5 c.
A reduction of almost 0.77% - and still almost the speed of the Iota bands.

So factoring in acceleration time still doesn't explain how the hell Apollo managed to shave 31 hours off. (Unless the old record was set down in maybe the Epsilon or Zeta bands - but then the majority of the improvement wouldn't be any surprise) I remain baffled.
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Re: Honorverse ramblings and musings
Post by cthia   » Thu Jul 20, 2017 4:39 am

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Jonathan_S wrote:
Jonathan_S wrote:Presumably. And in exchange for greatly increased risk you'll get somewhat better performance.

(For simplicity I'm going to ignore acceleration time and in-system manouvering as they should be irrelevant to the variable of hyper generator safety - though Truman was probably also redlining her compensator which I should calculate as it affects total passage time)

Even so, unless acceleration has a much larger impact than I assume, I can't get the numbers to make sense for Truman's speed run back to Manticore in HotQ.

It's only 31 light-years between Manticore and Grayson so even a warship traveling sedately down in the Eta bands (2576 c) needs less than 106 hours at full speed make the hyper transit.
We're told turning off all the interlocks let the damaged light cruiser Apollo "cut thirty hours off the old passage record". But to cover that distance in even 76 hours you need 3575 c. Which is basically warship in Iota bands speed (3600 c), substantially better than we're told a warship can do in the Theta bands (3000 c).
So already seems implausible even if we assume the old passage record was made loafing around in Eta bands.


It we assume is was set in the Theta bands, where warships can go (and dispatch boats routinely utilize) the hyper passage time should be under 91 hours at full speed. Chopping that to 61 hours would require a multiplier of 4500 c; exceeding what a streak drive can do (Kappa bands - 4354 c)

So something seems is screwy in HotQ. But like I said redoing the full calc, assuming no compensator safety margin might clear that up. I'll see if I can find time with my spreadsheets to run that.

Okay, going back to my reference material and attempting to do the full calcuations.

Apollo started out at Blackbird, within Uriel's 5 LM hyper limit. As what I believe is an Apollo-class CL her standard 80% accel was 418.8 G.

And for all of these we assume the small grav wave we know lies near Grayson on the way to Manticore either is too far, or too low a band, to be helpful.

Normal leisurely transit
Assume warship stays at 80% accel and only uses Eta bands

Boost for 111 minutes at 80% accel gets you 5 LM out (and up to 27.034 km/s)
Jump up to the Eta bands drops your velocity to roughly of that 0.00431% - 1.1659 km/s
Then 738 minutes to 0.6c (12 hours 18 minutes)
Then another 5960 minutes (99 1/3 hours) at 0.6c to reach Manticore
Then dropping back to n-space drops Apollo's velocity to 7.75 km/s (but she can now radio for help; her trip is complete)

Total transit time 6809 minutes (113.48 hours)


Emergency transit w/ hyper generator interlocks in place
Boost for 100 minutes at 100% accel (517.8 gees) gets you 5 LM out (and up to 30,448 km/s)
Jump up to the Theta bands drops your velocity to roughly 0.00207% of that - 0.630 km/s.
Then 591 minutes to 0.6c (9 hours 51 minutes)
Then another 5139 minutes (85.6 hours) at 0.6c to reach Manticore
Then dropping back to n-space drops Apollo's velocity to 3.72 km/s (but she can now radio for help; her trip is complete)

Total transit time 5800 minutes (96.66 hours)

So a savings, over a leasurly cruise, of 16.82 hours just from the higher hyper band and the full accel. We just need another 13.18 hours from the generator safety interlocks. That would reduce the effective times c multiplier from the 3575 c calculated before to "only" 3547.5 c.
A reduction of almost 0.77% - and still almost the speed of the Iota bands.

So factoring in acceleration time still doesn't explain how the hell Apollo managed to shave 31 hours off. (Unless the old record was set down in maybe the Epsilon or Zeta bands - but then the majority of the improvement wouldn't be any surprise) I remain baffled.


Unless you are willing to investigate her Δx you may be left empty. And you have to move up to calculus to do that. There is much more time saving to be obtained here. Start by reducing the integral of her Δx by half in both of the following figures and I think you'll be surprised. Frankly, I doubt half would even be needed for the modest eta you are driving for...

Then 738 minutes to 0.6c (12 hours 18 minutes)

Then 591 minutes to 0.6c (9 hours 51 minutes)


I will not do the calculations per certain promises I made before joining the forum and a certain little minx is just waiting to pounce. The forum is meant to be a reprieve from my own sordid calculations inside my own research. And because I don't care about RFC's performance figures on his missiles or ships. (Don't have the figures on distance between destinations, etc., anyway.) That rubs me the wrong way. The storyline is just fine for me without it. Besides, if I cared, I'd have stopped reading at the mere mention of Alice in Wonderland missiles being accelerated to .9c and other characters in Wonderland.

But if you or anyone else cares about it, do investigate her Δx.

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: Honorverse ramblings and musings
Post by Jonathan_S   » Thu Jul 20, 2017 8:36 am

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cthia wrote:[
Unless you are willing to investigate her Δx you may be left empty. And you have to move up to calculus to do that. There is much more time saving to be obtained here. Start by reducing the integral of her Δx by half in both of the following figures and I think you'll be surprised. Frankly, I doubt half would even be needed for the modest eta you are driving for...
I don't mind breaking out the calculus when applicable, but for constant acceleration it's unnecessary. (Or rather calculus already showed that integrating Δx for constant acceleration yields the handy formulas V = vi + at and D = vi + 1/2at^2)

Honorverse wedges aren't like chemical rockets, where the acceleration increases as the rockets burns away propellant. Nor are they like cars where drag causes acceleration to slow rapidly as you approach top speed. With those you do need to integrate to account for the change in acceleration over time.

But a wedge powered object, once the wedge comes up to full strength, happily retains a constant acceleration somehow magically ignoring even the effect of relativity until the object has reached whatever velocity it wants (or that it's rad shielding can handle)
And while it does take considerable time, it can be at least 40 minutes for a large ship, to bring a wedge from cold nodes up to the point it can start moving you, from that point to full power appears to be a negligible handful of seconds.


So I'm not seeing where calculus has room to affect those calculations. But if you point out where there's a change in acceleration over time to integrate I'd appreciate it.
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Re: Honorverse ramblings and musings
Post by cthia   » Thu Jul 20, 2017 1:25 pm

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Jonathan_S wrote:
cthia wrote:[
Unless you are willing to investigate her Δx you may be left empty. And you have to move up to calculus to do that. There is much more time saving to be obtained here. Start by reducing the integral of her Δx by half in both of the following figures and I think you'll be surprised. Frankly, I doubt half would even be needed for the modest eta you are driving for...
I don't mind breaking out the calculus when applicable, but for constant acceleration it's unnecessary. (Or rather calculus already showed that integrating Δx for constant acceleration yields the handy formulas V = vi + at and D = vi + 1/2at^2)

Honorverse wedges aren't like chemical rockets, where the acceleration increases as the rockets burns away propellant. Nor are they like cars where drag causes acceleration to slow rapidly as you approach top speed. With those you do need to integrate to account for the change in acceleration over time.

But a wedge powered object, once the wedge comes up to full strength, happily retains a constant acceleration somehow magically ignoring even the effect of relativity until the object has reached whatever velocity it wants (or that it's rad shielding can handle)
And while it does take considerable time, it can be at least 40 minutes for a large ship, to bring a wedge from cold nodes up to the point it can start moving you, from that point to full power appears to be a negligible handful of seconds.


So I'm not seeing where calculus has room to affect those calculations. But if you point out where there's a change in acceleration over time to integrate I'd appreciate it.


As you've noted, the formula you are using is for uniform acceleration. If the acceleration is not uniform then there is room for improvement. Is there a reason you do not wish to consider a nonuniform acceleration? Textev maybe?

Consider Dom's car in the Fast and Furious movie franchise. Dom's acceleration is uniform until he flips the nitrous oxide switch (NOS). If Dom had a series of these cylinders then his acceleration would not remain constant across the calculation. There would be increases in acceleration much akin to the Project Orion (nuclear pulse propulsion) design.


I'm not saying that this is how I think it all works when the safety interlocks are removed one way or the other.* However, it is obvious that you can account for the variance and reach your goal of shaving 31 hours off of the ETA if you do assume a nonuniform acceleration (perhaps even a pulsed acceleration). If not, then it appears as if you are stuck with trying to squeeze blood out of a turnip.

* Although admittedly when I first read about it in storyline and Alice's engineer went to play with his spanners, I continue to imagine him affixed to his readouts constantly retarding the insane bursts of acceleration to prevent BOOM.

Safety interlocks: I never imagined that the safety interlocks simply subsisted in a vacuum of spanners, but is assisted by computers and algorithms that constantly check/retard acceleration. In removing the safety interlocks, I imagine that the acceleration is no longer monitored as should be by computers and the engineer has to keep a watchful eye on the nonuniform bursts of acceleration.

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: Honorverse ramblings and musings
Post by The E   » Thu Jul 20, 2017 2:07 pm

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cthia wrote:As you've noted, the formula you are using is for uniform acceleration. If the acceleration is not uniform then there is room for improvement. Is there a reason you do not wish to consider a nonuniform acceleration? Textev maybe?


There is no textev anywhere that supports the idea that the maximum allowable acceleration as determined by the compensator fluctuates. Remember, the limit isn't the wedge's ability to provide propulsion, the limit is the compensator's ability to provide a survivable environment.

Consider Dom's car in the Fast and Furious movie franchise. Dom's acceleration is uniform until he flips the nitrous oxide switch (NOS). If Dom had a series of these cylinders then his acceleration would not remain constant across the calculation. There would be increases in acceleration much akin to the Project Orion (nuclear pulse propulsion) design.


Bad example. Neither NOS-boosting nor Orion-style pulsed propulsion are applicable models for how a wedge works.

I'm not saying that this is how I think it all works when the safety interlocks are removed one way or the other.* However, it is obvious that you can account for the variance and reach your goal of shaving 31 hours off of the ETA if you do assume a nonuniform acceleration (perhaps even a pulsed acceleration). If not, then it appears as if you are stuck with trying to squeeze blood out of a turnip.


But, again: This isn't how impellers work. There's an upper ceiling to the achievable acceleration that's determined by the Compensator, you cannot go past it unless you want to turn everyone aboard into smears on the bulkhead.

In removing the safety interlocks, I imagine that the acceleration is no longer monitored as should be by computers and the engineer has to keep a watchful eye on the nonuniform bursts of acceleration.


Nothing in the series supports the notion that impellers are prone to such inaccuracies. For all we know, the wedge provides a constant acceleration force all the time (assuming, of course, that no nodes fail; however, the only consequence of node failure that we've seen has been a drop in acceleration, not an increase).
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Re: Honorverse ramblings and musings
Post by Jonathan_S   » Thu Jul 20, 2017 2:09 pm

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cthia wrote:
Jonathan_S wrote:I don't mind breaking out the calculus when applicable, but for constant acceleration it's unnecessary. (Or rather calculus already showed that integrating Δx for constant acceleration yields the handy formulas V = vi + at and D = vi + 1/2at^2)

Honorverse wedges aren't like chemical rockets, where the acceleration increases as the rockets burns away propellant. Nor are they like cars where drag causes acceleration to slow rapidly as you approach top speed. With those you do need to integrate to account for the change in acceleration over time.

But a wedge powered object, once the wedge comes up to full strength, happily retains a constant acceleration somehow magically ignoring even the effect of relativity until the object has reached whatever velocity it wants (or that it's rad shielding can handle)
And while it does take considerable time, it can be at least 40 minutes for a large ship, to bring a wedge from cold nodes up to the point it can start moving you, from that point to full power appears to be a negligible handful of seconds.


So I'm not seeing where calculus has room to affect those calculations. But if you point out where there's a change in acceleration over time to integrate I'd appreciate it.


As you've noted, the formula you are using is for uniform acceleration. If the acceleration is not uniform then there is room for improvement. Is there a reason you do not wish to consider a nonuniform acceleration? Textev maybe?
Because all text-ev I'm aware of described wedges as providing uniform acceleration. And in places where time, accel, distance and/or velocity are all given it's possible to run the numbers and see that the numbers do in fact work out for with uniform acceleration.

If you have any evidence of non-uniform acceleration for wedges running at constant power I'd be very happy to see it.
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Re: Honorverse ramblings and musings
Post by cthia   » Thu Jul 20, 2017 2:32 pm

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I was merely offering an other suggestion of how a nonuniform acceleration could account for the discrepancy. I am in no way claiming a nonuniform acceleration -- certainly from a wedge in "normal" mode. I am not aware of textev of how a wedge reacts when the safety interlocks are removed so that leaves possibilities and room for improvement. 'Course if I missed textev regarding how a wedge functions or reacts with the safety interlocks removed please post, I'd be interested.

And of course, I was ignoring the compensators for sake of calculation and because I don't know how they do what they do, or if there is a notion of a "cushion" with that tech also, thus when the safety interlocks are removed they are pushed to unsafe, ill-recommended limits as well. This is the reason that my initial post warns that these improvements in ETA may be purely MAlign specific, as well as compensator improvements.

However, I don't see any other way to coax 31 more hours off of the ETA. It was only a recommendation for your peace of mind, because well, I don't care one way or the other. And well, the author's time shaving is textev.

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: Honorverse ramblings and musings
Post by munroburton   » Thu Jul 20, 2017 3:28 pm

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cthia wrote:I was merely offering an other suggestion of how a nonuniform acceleration could account for the discrepancy. I am in no way claiming a nonuniform acceleration -- certainly from a wedge in "normal" mode. I am not aware of textev of how a wedge reacts when the safety interlocks are removed so that leaves possibilities and room for improvement. 'Course if I missed textev regarding how a wedge functions or reacts with the safety interlocks removed please post, I'd be interested.


Mixing technologies up there, I think. IIRC, the safety interlocks were on the hyper generator - which has nothing to do with the impeller wedge or the compensator limits.

http://infodump.thefifthimperium.com/si ... gton/267/1

Clearly indicates that hyper generators are only actively used during translations - although they're routinely kept online in hyperspace in case starships need to avoid navigational hazards.

As for an explanation, it might be that the "safety interlocks" includes an automatic braking system which engages if sensors recognise that conditions ahead are worsening and starts shifting the ship towards a lower band or sub-band. It could be that this process is overridable by the helm, but the automatic trigger costs most ships several hours over the course of a voyage.

If that is what happens, then this could be where Alice Truman got her extra hours. Essentially, she pulled a Stig, turned traction control/ABS off and floored it all the way, rain or no rain. Lucky she didn't run into a storm(rogue grav wave).
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Re: Honorverse ramblings and musings
Post by Duckk   » Thu Jul 20, 2017 3:31 pm

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It's quite unambiguous from the text of HotQ that the safeties were on the hyper generator.

Also:

http://infodump.thefifthimperium.com/en ... ngton/68/1
-------------------------
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Re: Honorverse ramblings and musings
Post by cthia   » Thu Jul 20, 2017 6:06 pm

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Was not aware of the location of the subsystem. Although, it does not matter which subsystem the safety interlocks are a part for the theory I posited to hold water.

However, munroburton has a theory as well, so my point may be moot.

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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