How long does the fuel last?

[Seto Kaiba]

Like I said, its not a turbine, and is only vaguely like the described engine.

It's funny you should say that, because the extract I quoted very clearly and concisely states that it IS functioning as part of a jet turbine engine... of the turbofan type, to be specific. As described right there on page 31, the reactor effectively is the jet turbine engine's burner, with the reactor's waste heat being transferred to intake air to produce thrust. This is effectively the same tactic used in the thermonuclear reaction engines in Macross, as described in the previously cited publications.

And far FAR more importantly its fuel ratings, and thrust ratings are massively smaller.

The thrust ratings are, but remember that this is explicitly a scalable system and improvements in technology are expected to yield as much as fourfold improvement in efficiency. Such as it is, the projected 2.8lb of fuel per circumnavigation of the Earth as given both in Section 2.4.9 (page 34) and Section 2.5 (page 35) is nothing to sneeze at and wholly consistent with the OSM giving reaction engines an "effectively unlimited" sortie range in atmospheric service.

To get to the levels described in the show and OSM you are required to invoke handwave level improvements. Improvements that then take it off of "based on a theoretical device" to "technobabble that uses existing science for the buzzwords". At that point its sort of a stretch to claim that it is 'more realistic' than any other technobabble based non-realistic system.

Yes, there is some handwaving involved with respect to overtechnology... but that's not the point. The point is that the principles of the engine's operation are scientifically sound and that the kind of endurance cited in the RPG is a massive underrepresentation of a fusion engine's endurance even without that handwaving going on.

My assumption is that we have literally NOTHING to go on for the ease or efficiency of EITHER fuel. meaning that speculation on the relative merits of their production is quite literally simply dueling opinions as there are zero facts to support either stance.

We have multiple published papers to give us a fair indicator of how difficult it is to produce metallic hydrogen and slush hydrogen. These have both been cited already, and in the absence of a handwave to indicate that SLMH can be produced as easily as its more conventional cousins, we would have to accept that the data available thus far from research institutions indicates that producing a metallic hydrogen fuel in ANY quantities is going to be significantly more difficult than slush hydrogen simply because of the frankly colossal amount of energy that needs to be brought to bear. Are they both complex? Certainly. The difference is that the metallic option is orders of magnitude more difficult to make precisely because of the physics involved.

However since SLMH>HS if it were possible to make SLMH in our world it would also be being looked at as a fuel.

If, and only if, it were possible to produce SLMH in a fashion that was comparably economical to slush hydrogen or liquid hydrogen.

This is infact why MH is the subject of research, because it would make a great fuel, if we could just get it.

Can you cite a source for that? Because the only uses I've seen mentioned in connection with its experimental pursuit are as a high-temperature superconductor. Theoretically it could be used as a rocket fuel, but at present I'm not aware of anyone pursuing it for that reason because of the logistical impossibilities of making it.

Since the RT material establishes that they can make SLMH (unless we are going to claim that the canon RT material is wrong, [...]

Funnily enough, canon Robotech material makes no mention whatsoever of SLMH. The VF-1 Infopedia entries only say:

Powered by fusion engines, the VF-1 is fully space-capable, and is carried in great numbers on the SDF-1 as well as the Armor series of carriers.

From remarks I've seen copy-pasted from Jason Marker's facebook, SLMH was something he came up with in the absence of guidance from Harmony Gold on what the fusion engines used.

Amalgamated Fiction - Detroit: Yeah, except it's not. Not in the Macross part of the story anymore. Harmony Gold changed that, and now Protoculture isn't really A Thing until into the Southern Cross stuff. Do you think I just invented SLMH for the hell of it? To make a bunch of people mad? Because I get that **** /all/ the time from Robotech fans.
August 10, 2012 at 4:24pm

So short answer is "no there is nothing whatsoever to allow us to make any judgment on the relative merits of the production, or the required infrastructure."

Nothing except the known requirements for the formation of both substances as documented by credible research institutions... and that paints a picture that's rather unfavorable to metallic hydrogen.

I would also add that if the gravity systems that are used are found on spaceships.....then that would be a plausible reason for ship based SLMH production. I mean if you already have the gravity controls....

That's still operating on the baseless assumption that gravity control technology in the setting can reproduce the pressures needed to produce metallic hydrogen...

(If we were talking Macross, I could give it to you on the basis of VF engines catalyzing fusion via gravitational force as noted on the previously-cited technical documents... but in Robotech, we have no evidence to support the contention.)

I would also point out that we don't know the power needs of the gravity system, simply that they are found on spaceships with Reflex Furneces. There are light bulbs on those ships too, that does not mean that the light bulbs on the SDF-1 are special super power draining ones that can only be run off of Reflex Furnaces....

The RPG doesn't give fusion-powered spacecraft gravity control systems, which suggests that the technology is very energy-intensive as it can only be operated by reflex furnace-equipped craft.

I will check this out as well.

Happy reading, and may the eye-strain fairy forget to visit you after you're done... I cannot tell you the number of times I've slaved over a translation and had to knock off early with a headache because they print everything so bloody small.

[eliakon]

Like I said, its not a turbine, and is only vaguely like the described engine.

It's funny you should say that, because the extract I quoted very clearly and concisely states that it IS functioning as part of a jet turbine engine... of the turbofan type, to be specific. As described right there on page 31, the reactor effectively is the jet turbine engine's burner, with the reactor's waste heat being transferred to intake air to produce thrust. This is effectively the same tactic used in the thermonuclear reaction engines in Macross, as described in the previously cited publications.

I think we disagree on terminology...but that's fine its not a huge issue.

And far FAR more importantly its fuel ratings, and thrust ratings are massively smaller.

The thrust ratings are, but remember that this is explicitly a scalable system and improvements in technology are expected to yield as much as fourfold improvement in efficiency. Such as it is, the projected 2.8lb of fuel per circumnavigation of the Earth as given both in Section 2.4.9 (page 34) and Section 2.5 (page 35) is nothing to sneeze at and wholly consistent with the OSM giving reaction engines an "effectively unlimited" sortie range in atmospheric service.

-You do realize that the engine you are talking about weighs 20 tons...or 125% of the weight of the entire VF-1 itself..... (though it does
have a nice calculator that says it is 938lbs/MW of power...so how many MW of electrical power is needed to get the thrust you want?

-Not to mention that it uses H1-B11 fuel not pure H1 but I guess we can just pretend that the Boron is in some other tank or something....although as written this engine cant use HS, because HS doesn't have Boron in it.

To get to the levels described in the show and OSM you are required to invoke handwave level improvements. Improvements that then take it off of "based on a theoretical device" to "technobabble that uses existing science for the buzzwords". At that point its sort of a stretch to claim that it is 'more realistic' than any other technobabble based non-realistic system.

Yes, there is some handwaving involved with respect to overtechnology... but that's not the point. The point is that the principles of the engine's operation are scientifically sound and that the kind of endurance cited in the RPG is a massive underrepresentation of a fusion engine's endurance even without that handwaving going on.

Other than of course the minor detail that the engines in discussion have totally different fuels, and operate on totally different principles? Because the efficiency of a HS or SLMH engine is not something that a H/B engine can help us to figure out.

My assumption is that we have literally NOTHING to go on for the ease or efficiency of EITHER fuel. meaning that speculation on the relative merits of their production is quite literally simply dueling opinions as there are zero facts to support either stance.

We have multiple published papers to give us a fair indicator of how difficult it is to produce metallic hydrogen and slush hydrogen. These have both been cited already, and in the absence of a handwave to indicate that SLMH can be produced as easily as its more conventional cousins, we would have to accept that the data available thus far from research institutions indicates that producing a metallic hydrogen fuel in ANY quantities is going to be significantly more difficult than slush hydrogen simply because of the frankly colossal amount of energy that needs to be brought to bear. Are they both complex? Certainly. The difference is that the metallic option is orders of magnitude more difficult to make precisely because of the physics involved.

And once again nothing we have in the current literature takes into consideration the presence of Robotechnology, which sort of means that we have nothing to go on what the effects of RT on these processes is. This is rather important because the game establishes that SLMH can be produced. Ergo for any discussion of the game it is a provable fact that RT allows the creation of SLMH.

However since SLMH>HS if it were possible to make SLMH in our world it would also be being looked at as a fuel.

If, and only if, it were possible to produce SLMH in a fashion that was comparably economical to slush hydrogen or liquid hydrogen.

I remind you that energy density and remass needs are also important considerations. Since SLMH provides 10x the remass of HS, then it has its own values. An important consideration, where as cost is a secondary one.

This is infact why MH is the subject of research, because it would make a great fuel, if we could just get it.

Can you cite a source for that? Because the only uses I've seen mentioned in connection with its experimental pursuit are as a high-temperature superconductor. Theoretically it could be used as a rocket fuel, but at present I'm not aware of anyone pursuing it for that reason because of the logistical impossibilities of making it.

Correct, it is impossible to make it with current technology. However since it is provable that we can make it with Robotechnology, then the use of it in a Robotechnology setting becomes viable.

Since the RT material establishes that they can make SLMH (unless we are going to claim that the canon RT material is wrong, [...]

Funnily enough, canon Robotech material makes no mention whatsoever of SLMH. The VF-1 Infopedia entries only say:

Powered by fusion engines, the VF-1 is fully space-capable, and is carried in great numbers on the SDF-1 as well as the Armor series of carriers.

From remarks I've seen copy-pasted from Jason Marker's facebook, SLMH was something he came up with in the absence of guidance from Harmony Gold on what the fusion engines used.

Amalgamated Fiction - Detroit: Yeah, except it's not. Not in the Macross part of the story anymore. Harmony Gold changed that, and now Protoculture isn't really A Thing until into the Southern Cross stuff. Do you think I just invented SLMH for the hell of it? To make a bunch of people mad? Because I get that **** /all/ the time from Robotech fans.
August 10, 2012 at 4:24pm

Since this discussion was specifically what the fuel endurance of a vehicle in the RT game is, which was asked on a forum for the RT game, then it follows that the game is the area of discussion.
Jason Marker wrote that SLMH exists. HG blessed off on the book. Ergo the book is the canon for the game. Dot. Period. End of story.
Now you can argue what the fusion fuel in the anime was. Although personally when I see the fuel trucks fueling the VTs...they look like they are room-temperature fuel trucks and not cyrofuels....which would suggest that the anime was using some sort of room temperature liquid, and not a cryogenic, pressurized liquid.

So short answer is "no there is nothing whatsoever to allow us to make any judgment on the relative merits of the production, or the required infrastructure."

Nothing except the known requirements for the formation of both substances as documented by credible research institutions... and that paints a picture that's rather unfavorable to metallic hydrogen.

No, its a picture that says that HS is theoretically possible if certain technical issues are solved and that no one has figured out how to provide the conditions for making MH. Since we know that MH can be made in the RTgame, it follows that it is possible to make.

I would also add that if the gravity systems that are used are found on spaceships.....then that would be a plausible reason for ship based SLMH production. I mean if you already have the gravity controls....

That's still operating on the baseless assumption that gravity control technology in the setting can reproduce the pressures needed to produce metallic hydrogen...

Half true, it is pointing out that gravity control is one plausible way to get the needed pressures. And since the existence of something that can provide the pressure manifestly exists....

(If we were talking Macross, I could give it to you on the basis of VF engines catalyzing fusion via gravitational force as noted on the previously-cited technical documents... but in Robotech, we have no evidence to support the contention.)

Correct the discussion was the RT game. A game that has canonically established that SLMH exists, ergo something has to be able to make it.

I would also point out that we don't know the power needs of the gravity system, simply that they are found on spaceships with Reflex Furneces. There are light bulbs on those ships too, that does not mean that the light bulbs on the SDF-1 are special super power draining ones that can only be run off of Reflex Furnaces....

The RPG doesn't give fusion-powered spacecraft gravity control systems, which suggests that the technology is very energy-intensive as it can only be operated by reflex furnace-equipped craft.

Half true, the RPG doesn't say anything about what ships have gravity systems other than that the SDF-1 was equiped with 8 anti-gravity generators that it lost.
There is no word anywhere else about the presence of lack of gravity systems. Though since the SDF-1, and all zentradi ships, had to have artificial gravity (since they are not free-fall environments) we can infer that there was some gravity generation besides the lift systems. AFAIK there are no shots of the insides of any other ships to tell us if they had gravity systems or not.

[Seto Kaiba]

I think we disagree on terminology...but that's fine its not a huge issue.

Fair enough.

-You do realize that the engine you are talking about weighs 20 tons...or 125% of the weight of the entire VF-1 itself..... (though it does
have a nice calculator that says it is 938lbs/MW of power...so how many MW of electrical power is needed to get the thrust you want?

-Not to mention that it uses H1-B11 fuel not pure H1 but I guess we can just pretend that the Boron is in some other tank or something....although as written this engine cant use HS, because HS doesn't have Boron in it.

At the risk of poking a hole in this digression, the article is a proof of concept... not a statement that this exact implementation and its set of underlying assumptions is used as-is. It serves to illustrate that the principles behind the engine are sound and that SLMH isn't necessary to produce the endurance stated in the RPG.

Other than of course the minor detail that the engines in discussion have totally different fuels, and operate on totally different principles? Because the efficiency of a HS or SLMH engine is not something that a H/B engine can help us to figure out.

Three points here:

• The nitty-gritty details of the implementation are not relevant, this serves to demonstrate that the underlying principles behind the engine design are sound and that the endurance figures cited in the RPG do not actually require a superfuel like SLMH.
  
• Fusion is fusion... there's nothing that says these engine concepts can't run on other fusion-suitable materials, just that Hydrogen and Boron-11 were chosen for the set of assumptions in the study.
  
• We're only talking orders of magnitude here, so getting the efficiency of the engine down to a few minutes of runtime is not strictly necessary.

And once again nothing we have in the current literature takes into consideration the presence of Robotechnology, which sort of means that we have nothing to go on what the effects of RT on these processes is. This is rather important because the game establishes that SLMH can be produced. Ergo for any discussion of the game it is a provable fact that RT allows the creation of SLMH.

The game does not establish that robotechnology is used in the production of SLMH (or, really, say anything about SLMH's production at all). Even if we assume robotechnology cheats like gravity manipulation are in play, that doesn't eliminate the conditions needed to produce metallic hydrogen... it just potentially means they go about imposing those temperatures and pressures differently.

I remind you that energy density and remass needs are also important considerations. Since SLMH provides 10x the remass of HS, then it has its own values. An important consideration, where as cost is a secondary one.

Operating cost is normally a primary consideration, particularly when it comes to fuel...

Correct, it is impossible to make it with current technology. However since it is provable that we can make it with Robotechnology, then the use of it in a Robotechnology setting becomes viable.

Forgive me for saying so, but that has nothing to do with your contention that metallic hydrogen fuel research is being conducted...

Since this discussion was specifically what the fuel endurance of a vehicle in the RT game is, which was asked on a forum for the RT game, then it follows that the game is the area of discussion.
Jason Marker wrote that SLMH exists. HG blessed off on the book. Ergo the book is the canon for the game. Dot. Period. End of story.

Okay, that's rather different from what you initially said... I'll simply accept this as clarification of scope and say no more about it.

Now you can argue what the fusion fuel in the anime was. Although personally when I see the fuel trucks fueling the VTs...they look like they are room-temperature fuel trucks and not cyrofuels....which would suggest that the anime was using some sort of room temperature liquid, and not a cryogenic, pressurized liquid.

So... a few points again:

• When, precisely, do we see fuel trucks in the animation? There's a hangar shot where we see a tank of something, but it isn't identifiable as fuel and the hose coming out of it is not hooked up to any of the identified fueling ports on the VF-1.
  
• Palladium's art for the tank in question has a conspicuously visible pressure gauge, and it is described as capable of transporting cryofluids.
  
• Cryofluid transport trucks don't always look all that different from a normal tanker truck... this I know from firsthand experience, being that I work in alt-fuels for the auto industry and the walk from my office to my lab takes me right through the fuel yard where we store, among other things, liquid hydrogen and nitrogen.

Half true, it is pointing out that gravity control is one plausible way to get the needed pressures. And since the existence of something that can provide the pressure manifestly exists....

It's theoretically possible, but it's not within the scope of the demonstrated capabilities of the technology in the series... so it's still baseless.

Half true, the RPG doesn't say anything about what ships have gravity systems other than that the SDF-1 was equiped with 8 anti-gravity generators that it lost.
There is no word anywhere else about the presence of lack of gravity systems.

Actually, on review, you are completely correct on this.

[eliakon]

-You do realize that the engine you are talking about weighs 20 tons...or 125% of the weight of the entire VF-1 itself..... (though it does
have a nice calculator that says it is 938lbs/MW of power...so how many MW of electrical power is needed to get the thrust you want?

-Not to mention that it uses H1-B11 fuel not pure H1 but I guess we can just pretend that the Boron is in some other tank or something....although as written this engine cant use HS, because HS doesn't have Boron in it.

At the risk of poking a hole in this digression, the article is a proof of concept... not a statement that this exact implementation and its set of underlying assumptions is used as-is. It serves to illustrate that the principles behind the engine are sound and that SLMH isn't necessary to produce the endurance stated in the RPG.

That's the point though. It DOESNT show that, since the system shown wont work for these needs. The H/B engines are too massive for the VF project....which might be solvable by using a fuel with 10x the energy density though.....

Other than of course the minor detail that the engines in discussion have totally different fuels, and operate on totally different principles? Because the efficiency of a HS or SLMH engine is not something that a H/B engine can help us to figure out.

Three points here:

• The nitty-gritty details of the implementation are not relevant, this serves to demonstrate that the underlying principles behind the engine design are sound and that the endurance figures cited in the RPG do not actually require a superfuel like SLMH.

Except that the demonstrated principles don't work with the listed fuels....so we do need either a better engine, or a better fuel.

Fusion is fusion... there's nothing that says these engine concepts can't run on other fusion-suitable materials, just that Hydrogen and Boron-11 were chosen for the set of assumptions in the study.

Uh no, different forms of fusion have different energy releases. That is the entire reason why H/B, HS, and SLMH would exist, each one has a different energy density. One cant just say 'well all internal combustion is the same, so diesel and jet fuel are interchangeable'

We're only talking orders of magnitude here, so getting the efficiency of the engine down to a few minutes of runtime is not strictly necessary.

Ummmm I would say that 'orders of magnitude' is a HUGE issue when talking about if a technology can be implemented.
Especially when one possible solution to that is to use a fuel that is an order of magnitude more energetic.....

And once again nothing we have in the current literature takes into consideration the presence of Robotechnology, which sort of means that we have nothing to go on what the effects of RT on these processes is. This is rather important because the game establishes that SLMH can be produced. Ergo for any discussion of the game it is a provable fact that RT allows the creation of SLMH.

The game does not establish that robotechnology is used in the production of SLMH (or, really, say anything about SLMH's production at all). Even if we assume robotechnology cheats like gravity manipulation are in play, that doesn't eliminate the conditions needed to produce metallic hydrogen... it just potentially means they go about imposing those temperatures and pressures differently.

It doesn't say that they aren't. ALL we know is that a RT capable civilization is capable of making SLMH.

I remind you that energy density and remass needs are also important considerations. Since SLMH provides 10x the remass of HS, then it has its own values. An important consideration, where as cost is a secondary one.

Operating cost is normally a primary consideration, particularly when it comes to fuel...

Not for military operations. For the military mission needs come first, and budget comes second. So if the fuel that allows the mission to work costs ten times as much than a fuel that doesn't....then the fuel that works will be selected.
The ONLY important criteria is "will it do the job" THEN after that is settled you can look at the options that will do the job. If SLMH works and HS doesn't....then HS will never be selected regardless of cost.

Correct, it is impossible to make it with current technology. However since it is provable that we can make it with Robotechnology, then the use of it in a Robotechnology setting becomes viable.

Forgive me for saying so, but that has nothing to do with your contention that metallic hydrogen fuel research is being conducted...

My point was that we can not do any of the research we need, because we don't have the tools that the people in the show have.

Now you can argue what the fusion fuel in the anime was. Although personally when I see the fuel trucks fueling the VTs...they look like they are room-temperature fuel trucks and not cyrofuels....which would suggest that the anime was using some sort of room temperature liquid, and not a cryogenic, pressurized liquid.

So... a few points again:

• When, precisely, do we see fuel trucks in the animation? There's a hangar shot where we see a tank of something, but it isn't identifiable as fuel and the hose coming out of it is not hooked up to any of the identified fueling ports on the VF-1.

How many tanker trucks do you have in military hangers that are NOT fuelers?

Palladium's art for the tank in question has a conspicuously visible pressure gauge, and it is described as capable of transporting cryofluids.

Cryofluid transport trucks don't always look all that different from a normal tanker truck... this I know from firsthand experience, being that I work in alt-fuels for the auto industry and the walk from my office to my lab takes me right through the fuel yard where we store, among other things, liquid hydrogen and nitrogen.

The problem with these is that HS has to be kept at an exact specific pressure/temperature or it fails. This is different than liquefied gas that just needs to be kept cool.

Half true, it is pointing out that gravity control is one plausible way to get the needed pressures. And since the existence of something that can provide the pressure manifestly exists....

It's theoretically possible, but it's not within the scope of the demonstrated capabilities of the technology in the series... so it's still baseless.

I wasn't saying it WAS the solution. I was saying that it provides a POSSIBLE solution, thus proving the claim 'it cant be done' false.

[Seto Kaiba]

That's the point though. It DOESNT show that, since the system shown wont work for these needs. The H/B engines are too massive for the VF project....which might be solvable by using a fuel with 10x the energy density though.....

*Sigh* No, you're fixating on the specific set of assumptions in the article... all it serves as for our purposes is proof of the basic implementation concept's viability.

Except that the demonstrated principles don't work with the listed fuels....so we do need either a better engine, or a better fuel.

Uh no, different forms of fusion have different energy releases. That is the entire reason why H/B, HS, and SLMH would exist, each one has a different energy density. One cant just say 'well all internal combustion is the same, so diesel and jet fuel are interchangeable'

Where is this coming from? The CBFR design is intended for aneutronic fusion reactions... Hydrogen-Boron[sup]11[/sup] is one of the candidate fuels, but Hydrogen-Hydrogen fusion is also aneutronic. Yes, different forms of fusion have different energy releases, but the CBFR technology can be applied to any fusion that can be catalyzed by inertial confinement and bombardment, and the principles behind the engine concept will work with any kind of fusion reactor because the sole requirement is the production of waste heat.

ALL we know is that a RT capable civilization is capable of making SLMH.

True, but that doesn't change the physics behind the creation of metallic hydrogen.

How many tanker trucks do you have in military hangers that are NOT fuelers?

Depends where you are... in the field, you could just as easily have tanker trucks full of water, fire suppressant foam, or various system-vital fluids like lubricants, coolants, etc.

The problem with these is that HS has to be kept at an exact specific pressure/temperature or it fails. This is different than liquefied gas that just needs to be kept cool.

[/quote]
Doesn't mean the tank there is meant for long-term fuel storage... could just as easily be for short-term fuel transfers between a storage depot and the hangar deck. There's plenty of room on the chassis of the refueling vehicle in the RPG for there to be a chiller system as well.

[glitterboy2098]

the CBFR is not being used as a means of direct thrust.

Pg23: "Both ends of the CBFR would be "closed.""
Pg24: "There is no exhaust;"
"Unlike chemical reaction-based P/P systems, there would be no measurable aircraft weight
change during flight"

so the reactor is fully closed, with nothing escaping. it generates no exhaust and thus no thrust, and all it's byproducts are stored on the aircraft until landing.

so how does it generate propulsion?

pg23: "Electric motors that drive fans would be used for propulsion, as previously presented."

so how does that work?

pg4: "ultralight, ultraefficient cryogenic electric motors, coupled to fans, to provide
propulsion;"

so wow, not a fusion rocket at all, nor is it a traditional jet engine set up.
in fact it's a pure electric Ducted Fan. Remote control aircraft technology scaled up to full sized planes.

wait you'll say, what about the "turbojet" variant?
well that one isn't using the reactor for thrust, it's using its waste heat to heat the air passing through the ducted fan. this saves it half a ton of mass (goes from 20 tons to 19.5) and nets it.. a total of 12,655 lbs of overall thrust.

pg31: "This section presents a high level investigation and analysis of a concept of not merely removing
CBFR surface heat but incorporating the CBFR into the equivalent of a turbojet engine so that
this heat may provide some of the propulsive force required by the aircraft.
In this concept, the CBFR is to be thought of as a (nearly) fueless burner. Ambient air is
compressed, heated by the CBFR, expanded, and exhausted through a turbine and nozzle,
thereby providing thrust. There are no combustion-related chemical compounds to change the
composition of the air as it passes through the engine"

for referance, a modern F110 Jet engine (used on most NATO jets) is about 29,000lbs of thrust. at a mass of 2 tons.

so not only is is not a fusion rocket, it is not even better than a currently cutting edge military jet engine. this NASA ducted fan system 10x the mass and less than half the thrust.


nor does the fuel work out.. it's not slush hydrogen or metallic hydrogen.

pg22: "The preferred fusion reaction for either geometry is the one between ordinary hydrogen (H1) and
the most common isotope of boron with atomic weight 11 (B11):"
pg23: "There would be no cryogenic hydrogen (LH2) onboard the aircraft."

so non-cryogenic, ambient condition hydrogen gas, and a supply of Boron, which being solid at ambient conditions, is probably in powder form.


sorry seto.. this whitepaper on hypothetical high endurance low thrust electric ducted fans is not applicable to robotech or macross fusion rocket design.

[eliakon]

However since SLMH>HS if it were possible to make SLMH in our world it would also be being looked at as a fuel.

If, and only if, it were possible to produce SLMH in a fashion that was comparably economical to slush hydrogen or liquid hydrogen.

This is infact why MH is the subject of research, because it would make a great fuel, if we could just get it.

Can you cite a source for that? Because the only uses I've seen mentioned in connection with its experimental pursuit are as a high-temperature superconductor. Theoretically it could be used as a rocket fuel, but at present I'm not aware of anyone pursuing it for that reason because of the logistical impossibilities of making it.

http://www.nasa.gov/directorates/spacet ... rogen.html
http://www.nature.com/news/metallic-hyd ... ed-1.10817
http://www.nasa.gov/directorates​/spacetech/niac/silvera_metallic_​hydrogen.html#.Vj-3QCvuEX8
https://www.newscientist.com/art​icle/mg21128253-100-nasa-bets-on-​metallic-hydrogen-and-cosmic-gas-​stations/
http://nextbigfuture.com/2012/03​/metallic-hydrogen-game-changing-​rocket.html
http://iopscience.iop.org/article/10.10 ... 012194/pdf

I think that is pretty good evidence that Metalic Hydrogen is being explored as a viable and desirable rocket fuel.

[Seto Kaiba]

wait you'll say, what about the "turbojet" variant?
well that one isn't using the reactor for thrust, it's using its waste heat to heat the air passing through the ducted fan.

You really should have read the previous posts before posting, as we have already covered the subjects you're attempting to raise in considerable detail.

As noted previously via the citations from Macross Journal Extra: VF-1 Valkyrie Special Edition, Macross Chronicle, the various volumes of Variable Fighter Master File, Great Mechanics.DX, and other sources, this is in principle almost the exact implementation used on Macross's thermonuclear reaction turbine engines in their air-breathing mode. The key area of difference in function is that thermonuclear reaction turbine engines of the Macross OSM have the reactor set up to operate in both the "closed" mode like the CFBR turbojet described on page 31 and an "open" mode like the CFBR-SPS rocket presented in that diagram on page 21. When the engines are operating in atmosphere, the reactor is "closed" and the heat from the reaction is used for heating intake air in what would be the combustion stage on a normal turbine engine. In space, the reactor is run "open" and it works like a fusion rocket... albeit with a helping hand from an ion engine system in the tail end of the turbine.

so not only is is not a fusion rocket, it is not even better than a currently cutting edge military jet engine. this NASA ducted fan system 10x the mass and less than half the thrust.

As noted previously, this document was cited as an example of the principles behind the engine concept.

nor does the fuel work out.. it's not slush hydrogen or metallic hydrogen.

The document cites one of several different aneutronic fusion fuel options... that doesn't invalidate the point by any means.

sorry seto.. this whitepaper on hypothetical high endurance low thrust electric ducted fans is not applicable to robotech or macross fusion rocket design.

[/quote]
Please refer to the remarks above in and previous posts for a detailed explanation as to why your conclusion here is incorrect.

[eliakon]

wait you'll say, what about the "turbojet" variant?
well that one isn't using the reactor for thrust, it's using its waste heat to heat the air passing through the ducted fan.

You really should have read the previous posts before posting, as we have already covered the subjects you're attempting to raise in considerable detail.

As noted previously via the citations from Macross Journal Extra: VF-1 Valkyrie Special Edition, Macross Chronicle, the various volumes of Variable Fighter Master File, Great Mechanics.DX, and other sources, this is in principle almost the exact implementation used on Macross's thermonuclear reaction turbine engines in their air-breathing mode. The key area of difference in function is that thermonuclear reaction turbine engines of the Macross OSM have the reactor set up to operate in both the "closed" mode like the CFBR turbojet described on page 31 and an "open" mode like the CFBR-SPS rocket presented in that diagram on page 21. When the engines are operating in atmosphere, the reactor is "closed" and the heat from the reaction is used for heating intake air in what would be the combustion stage on a normal turbine engine. In space, the reactor is run "open" and it works like a fusion rocket... albeit with a helping hand from an ion engine system in the tail end of the turbine.

so not only is is not a fusion rocket, it is not even better than a currently cutting edge military jet engine. this NASA ducted fan system 10x the mass and less than half the thrust.

As noted previously, this document was cited as an example of the principles behind the engine concept.

Except of course that the principles DONT WORK
Unless we apply magical super science to increase the power by orders of magnitude, while assuming (with out any basis mind you) that we can simply change the fuel for any other fuel we like, while changing the kind of fusion engine....
In which case we have changed all the starting principles and are left with "fusion engines on airplanes might work"....
And that takes us back to "Why pick HS over SLMH" because this article has nothing to do with HS, and thus shows no reason, what so ever, to assume that HS should be used over SLMH.
Quite literally this paper is equally supportive of SLMH as it is of HS (or any other fusion fuel that is not H(gas)/B.

[Jefffar]

And none of these papers presupposes a society with the limitless powersource of Protoculture or gravity control technology, both of which exist in Robotech and make the production of SLMH in industrial amounts very plausible.

[Seto Kaiba]

Except of course that the principles DONT WORK
Unless we apply magical super science to increase the power by orders of magnitude, while assuming (with out any basis mind you) that we can simply change the fuel for any other fuel we like, while changing the kind of fusion engine....

Step back for a moment. Right now you're so fixated on the minutae of the paper you're missing the bigger picture.

What do the basic facts here tell us?

Is it possible to have one reactor technology that can function equally well as both a space-use fusion rocket AND an atmospheric fusion-powered jet turbine engine? Emphatically yes.
Is it possible to have that reactor-based engine deliver far more flight time than even the RPG says? Again, the answer is yes.
Is the fundamental technology underlying the reactor concept described in the paper workable with hydrogen-based fuels? Yes.[sup]1[/sup]
Beyond the specifics of the reaction itself, do the engines in the OSM work on the principles outlined in the paper? Yes.
Is metallic hydrogen going to require vastly more energy to produce than more conventional and accessible alternatives like slush and liquid hydrogen? Yes.
Is metallic hydrogen necessary to achieve the endurance described in the RPG or the paper? No.
Is metallic hydrogen going to produce more energy per unit of fuel mass than conventional alternatives? No.

And none of these papers presupposes a society with the limitless powersource of Protoculture or gravity control technology, both of which exist in Robotech and make the production of SLMH in industrial amounts very plausible.

You're right that the papers don't assume the existence of protoculture or gravity control, but you're wrong to assume these things are factors in the fuel equation at all.

We have not seen a single piece of evidence that humanity is able to produce gravity control technology with the precision or the power to do anything other than lift a starship via anti-gravity. There is no evidence that gravity control in Robotech is even capable of producing an intense enough gravitational field to apply 3.2 million atmospheres of pressure to hydrogen... or, really, any levels of gravity between 1g and (apparently) -1g.

Second, protoculture is not by any means a limitless power source. It's the most scarce substance in the universe, and all we have as far as official statements of its potency is that it has greater energy density than "conventional nuclear sources". What exactly a "conventional nuclear source is, they don't say. Is it fission fuels like Uranium and Plutonium? Fusion fuels like hydrogen isotopes? It's not said... and protoculture is depicted as being used in very small quantities, so while your protoculture reactor's fuel slug may have more energy per unit of mass than a "conventional nuclear source", that doesn't mean a protoculture power source will trump conventional alternatives at any scale.


1. The typical fuel for an inertial confinement fusion reactor is hydrogen or hydrogen isotopes.

[eliakon]

Except of course that the principles DONT WORK
Unless we apply magical super science to increase the power by orders of magnitude, while assuming (with out any basis mind you) that we can simply change the fuel for any other fuel we like, while changing the kind of fusion engine....

Step back for a moment. Right now you're so fixated on the minutae of the paper you're missing the bigger picture.

Okay, I'll bite

What do the basic facts here tell us?

Is it possible to have one reactor technology that can function equally well as both a space-use fusion rocket AND an atmospheric fusion-powered jet turbine engine? Emphatically yes.

Yep...and this applies to both engines so there is nothing to support either one

Is it possible to have that reactor-based engine deliver far more flight time than even the RPG says? Again, the answer is yes.

The answer is No actually. Because the RPG engine has a radically higher thrust needed. More thrust needs more fuel....
You cant look at the MPG of a smart car and assume that the numbers will apply to a drag racer.

Is the fundamental technology underlying the reactor concept described in the paper workable with hydrogen-based fuels? Yes.[sup]1[/sup]

Again not argued, because we are both talking about Hydrogen fuels.

Beyond the specifics of the reaction itself, do the engines in the OSM work on the principles outlined in the paper? Yes.

No. I highly disagree here. This is not the described technology, it is vaguely similar but it still has major differences. Its like saying that we should assume that all forms of steam engine are the same....

Is metallic hydrogen going to require vastly more energy to produce than more conventional and accessible alternatives like slush and liquid hydrogen? Yes.

Not supported. Since we have not actually SOLVED the issue of HS, the issue of what is required to make MH is still being worked on, and of course there is the infrastructural costs.
Basically your making an unfounded assumption on this based on your personal interpretation of what is needed.

Is metallic hydrogen necessary to achieve the endurance described in the RPG or the paper? No.

The endurance in the RPG is not at all relevant to the paper.
The amount of fuel needed for the simple, low power, low density engine in the paper is utterly irelevent to the amount of fuel needed for a high power, high density engine.
This is quite literally comparing Apples and Oranges.

Is metallic hydrogen going to produce more energy per unit of fuel mass than conventional alternatives? No.

Sorry, but based on the links I provided NASA seems to think that it will. As such I am going to have to side with them and their expert opinions. Though if you have a peer-reviewed paper that you have written on the subject I would be happy to entertain it.

And none of these papers presupposes a society with the limitless powersource of Protoculture or gravity control technology, both of which exist in Robotech and make the production of SLMH in industrial amounts very plausible.

You're right that the papers don't assume the existence of protoculture or gravity control, but you're wrong to assume these things are factors in the fuel equation at all.

Actually we don't know anything involed in the fuel equasion, so claims either way are unsupported opinion.
THAT said when we know that they DO have access to the vast energy supply of Reflex Furnaces it is odd to claim that they will not have the energy needed for the creation of their fuel as it is demonstrable that they DO have sufficient energy supplies.

We have not seen a single piece of evidence that humanity is able to produce gravity control technology with the precision or the power to do anything other than lift a starship via anti-gravity. There is no evidence that gravity control in Robotech is even capable of producing an intense enough gravitational field to apply 3.2 million atmospheres of pressure to hydrogen... or, really, any levels of gravity between 1g and (apparently) -1g.

Actually we have evidence that they are able to use gravity control to make artificial gravity for their ships allowing earth normal gravity fields. And since we see this in the canon comics as occurring on human built space ships we know that human built systems can do this.

Second, protoculture is not by any means a limitless power source. It's the most scarce substance in the universe, and all we have as far as official statements of its potency is that it has greater energy density than "conventional nuclear sources". What exactly a "conventional nuclear source is, they don't say. Is it fission fuels like Uranium and Plutonium? Fusion fuels like hydrogen isotopes? It's not said... and protoculture is depicted as being used in very small quantities, so while your protoculture reactor's fuel slug may have more energy per unit of mass than a "conventional nuclear source", that doesn't mean a protoculture power source will trump conventional alternatives at any scale.

Apparently they had enough supplies of what ever is needed to make Reflex Furnaces work to build 2+ Grand Cannons, all the ARMD space ships, the Mars base and the rest....

1. The typical fuel for an inertial confinement fusion reactor is hydrogen or hydrogen isotopes.

And now we are simply proving that Hydrogen is the fuel.
Since BOTH HS and SLMH are Hydrogen this proves literally nothing.

[Jefffar]

And none of these papers presupposes a society with the limitless powersource of Protoculture or gravity control technology, both of which exist in Robotech and make the production of SLMH in industrial amounts very plausible.

You're right that the papers don't assume the existence of protoculture or gravity control, but you're wrong to assume these things are factors in the fuel equation at all.

We have not seen a single piece of evidence that humanity is able to produce gravity control technology with the precision or the power to do anything other than lift a starship via anti-gravity. There is no evidence that gravity control in Robotech is even capable of producing an intense enough gravitational field to apply 3.2 million atmospheres of pressure to hydrogen... or, really, any levels of gravity between 1g and (apparently) -1g.

That goes both ways, as there is an equal lack of proof that their gravity control technology doesn't allow them to achieve the necessary pressure to produce SLMH effectively and safely. Their is also a lack of proof that they don't have some other way to produce SLMH.

All we have is that in the RPG SLMH is the fuel of choice for two generations of mecha which means it has to be produced, stored and transported in significant quantities which implies that they have found a way to make it economically or the unique properties of SLMH are such that it is worth the expense to produce over cheaper fuel sources.

[Seto Kaiba]

Is it possible to have that reactor-based engine deliver far more flight time than even the RPG says? Again, the answer is yes.

The answer is No actually. Because the RPG engine has a radically higher thrust needed. More thrust needs more fuel....
You cant look at the MPG of a smart car and assume that the numbers will apply to a drag racer.

Even if we account for that by, say, assuming that the engine is consuming ten times as much fuel to produce the necessary speed, we're still 2x or better the RPG's estimate.

Admittedly, this is more a problem for the Robotech engine's conventional fusion process... where the engine is likely getting only 0.42 MeV out of the hydrogen-hydrogen reaction via inertial confinement or magnetic confinement fusion, compared to the 8.7 MeV a H1-B11 reactor gets. The Macross OSM's thermonuclear reaction power system is controlled via gravity manipulation, which would enable the engine to exploit the proton-proton chain to push the H1-H1 total power yield up over 26.22 MeV. (A little over 3x the output of H1-B11 for the same quantity of fuel.)

No. I highly disagree here. This is not the described technology, it is vaguely similar but it still has major differences. Its like saying that we should assume that all forms of steam engine are the same....

The only appreciable difference is how we're producing the reaction... that doesn't actually make a difference to how the engine itself functions.

Not supported. Since we have not actually SOLVED the issue of HS, the issue of what is required to make MH is still being worked on, and of course there is the infrastructural costs.
Basically your making an unfounded assumption on this based on your personal interpretation of what is needed.

We're making an estimation based on the sheer amount of energy necessary to impose the pressures under which metallic hydrogen forms... it's an orders-of-magnitude energy difference between that and slush hydrogen via the vacuum continuous-freeze process, and I'm being charitable enough to assume (impossible) perfect efficiency in the compression system.

Is metallic hydrogen going to produce more energy per unit of fuel mass than conventional alternatives? No.

Sorry, but based on the links I provided NASA seems to think that it will. As such I am going to have to side with them and their expert opinions. Though if you have a peer-reviewed paper that you have written on the subject I would be happy to entertain it.

... per unit of fuel mass? I think you may want to rethink that one.

A cubic centimeter of metallic hydrogen is going to be (approximately) ten times as dense as a cubic centimeter of slush hydrogen, and consequentially have (approximately) ten times the mass. The mass of hydrogen is a constant.

THAT said when we know that they DO have access to the vast energy supply of Reflex Furnaces it is odd to claim that they will not have the energy needed for the creation of their fuel as it is demonstrable that they DO have sufficient energy supplies.

There's that overestimation of the availability and output of reflex furnaces again... we don't know what the output of a reflex furnace is, even by rough approximation. We know only that the fuel, per unit of fuel mass, can produce more energy than a "conventional" nuclear source. The implementations described in Robotech seem to put much more emphasis on endurance rather than high output...

Actually we have evidence that they are able to use gravity control to make artificial gravity for their ships allowing earth normal gravity fields. And since we see this in the canon comics as occurring on human built space ships we know that human built systems can do this.

See again, 1g to -1g. That's a long, LONG way from the kind of force necessary to produce metallic hydrogen.

Apparently they had enough supplies of what ever is needed to make Reflex Furnaces work to build 2+ Grand Cannons, all the ARMD space ships, the Mars base and the rest....

Several points of order...

• Captain Gloval tells Lisa in the series (Ep15, IIRC) that the Grand Cannons are powered by Earth's gravitational field.
• The RPG says the ARMDs are powered by fusion reactors.
• Mars base had a single reflex furnace, which the comics establish was a test unit.
• Later ships are, per the RPG, built around salvaged reflex furnace systems from Zentradi ships.
• The Shadow Chronicles movie indicates that the UEEF's total fuel stockpile is only sufficient to keep them operating for 1 year, which is actually less than the stated endurance of most ships in the RPG...

Those points poke an awful big hole in the idea that they had massive stockpiles of protoculture...

[ShadowLogan]

Is it possible to have that reactor-based engine deliver far more flight time than even the RPG says? Again, the answer is yes.

The answer is No actually. Because the RPG engine has a radically higher thrust needed. More thrust needs more fuel....

Actually more thrust does not by default require more fuel. Thrust in a reaction engine, like a rocket, is based on several variables:
-mass of the propellant, used per unit of time (second)
-velocity of the propellant being expelled (which itself is determined by several factors, including temperature and pressure) in the same time frame as the rate the mass is being used
-pressure of the escaping gases in certain parts of the engine, and even external ambient environment pressure
-exit area size for the escaping gases
-unless we are dealing with an aerospike engine, the nozzle design itself can have an impact on producing more or less thrust

... per unit of fuel mass? I think you may want to rethink that one.

I've seen estimates for Metallic Hydrogen Rocket engine that produces 6000K+ temperatures (IIRC that is using it as a pure mono-propellant, and not with LOX), which far exceeds available materials used in rocket engines today. From a Specific Impulse standpoint, the Metallic Hydrogen fuel offers much higher values than LH2 (and likely slush, though I haven't seen any values for slush than I can recall), the Shuttle's LH2/LOX main engines have efficiency of around 460seconds. Metallic Hydrogen Fuel is estimated to be over 1000seconds (the exact value depends on how/if it is diluted and if using LOX or not). So yes per unit of mass, the energy contained in Metallic Hydrogen is greater than LH2 and Slush.

Captain Gloval tells Lisa in the series (Ep15, IIRC) that the Grand Cannons are powered by Earth's gravitational field.

And in "Force of Arms" the facility is calling for Reflex Modules to be brought online in relation to the Grand Cannon, IIRC (I know it was Reflex something as i don't have the quote handy).

[glitterboy2098]

Reflex furnaces. the Canon comic "Invasion" with its mars base sera sidestory confirms reflex furnaces as well.. the zentreadi detect one on mars, built to similar specs as the SDF-1's, and investigate in such a way to trigger a shooting incident. the base commander then uses a prototype reflex cannon to destroy the zent ship. the reflex cannon is described as a human development. they couldn't duplicate the SDF-1's twin boom design, but found a way to draw extra power from the gravitational field of a planet to boost the yield, and their design uses gravity generators to shape the beam and release it in one "synchronous" burst.

the visuals of the prototype look a lot like the Synchrocannons on ships in shadow chronicles. (also establishes that humanity was fairly adept at gravity control before the first war.. the date was 2005)

the end scene of the 2005 part of the comic was admiral hayes receiving a letter from Lang, where it's established that Lang has modified the gravity generators on the SDF-1. that since i no longer had a crew of 40ft giants, they didn't need as much regular gravity control, and he'd instead rechannelled that excess power into more anti-gravity capability. though he expresses his crew's doubt as to whether the SDF-1's frame can handle the extra strain from the extra antigravity ability.

which frankly also establishes humanity was fairly adept at gravity control even early on, and that the antigravity would have been values greater than just "1 to -1".

[Seto Kaiba]

I've seen estimates for Metallic Hydrogen Rocket engine that produces 6000K+ temperatures [...]

Lemme stop you there for three reasons...

The first is that we're talking about [liquid/slush/metallic] hydrogen as fuel for a fusion reactor, not a rocket. It doesn't matter how dense the fuel material is, you will never get more than 0.42 MeV out of a H1-H1 fusion reaction unless you can produce the fusion reaction at a temperature/pressure sufficient to exploit either the proton-proton chain or CNO chain. Apples and oranges, man.

The second is that the only paper on the subject I've been able to locate (here) makes no bones about those figures being purely theoretical and the math to validate their assumptions is noticeably absent.

The third is that you're trying to compare two different forms of energy release... combustion vs. dissociation. Again, apples and oranges.

the reflex cannon is described as a human development.

Which is odd, to say the least, since the one on the SDF-1 is factory-original equipment... it's not exactly a human development if they just copied something someone else built.

they couldn't duplicate the SDF-1's twin boom design, but found a way to draw extra power from the gravitational field of a planet to boost the yield, and their design uses gravity generators to shape the beam and release it in one "synchronous" burst.

That makes even less sense than the above... reflex cannons are canonically particle beam weapons, gravity would be useless as a way of focusing the beam.

(also establishes that humanity was fairly adept at gravity control before the first war.. the date was 2005)

It establishes that humanity had found a way to generate power from a gravitational field, yes...

the end scene of the 2005 part of the comic was admiral hayes receiving a letter from Lang, where it's established that Lang has modified the gravity generators on the SDF-1. that since i no longer had a crew of 40ft giants, they didn't need as much regular gravity control, and he'd instead rechannelled that excess power into more anti-gravity capability. though he expresses his crew's doubt as to whether the SDF-1's frame can handle the extra strain from the extra antigravity ability.

which frankly also establishes humanity was fairly adept at gravity control even early on, and that the antigravity would have been values greater than just "1 to -1".

That the gravity control systems literally tore their way out of the ship instead of lifting it rather strongly argues that they weren't nearly as adept with the technology as you give them credit for. Even if we accept this as "proof" that the SDF-1's gravity control system was capable of more than 1G to -1G of power, that doesn't put it anywhere near the ballpark of inducing gravity levels high enough to impose pressures of hundreds of gigapascals.

(In Robotech, they don't establish that that was the alien boobytrap scrambling an otherwise perfectly functional system the way they do in Macross's version of Global Report.)

[eliakon]

I've seen estimates for Metallic Hydrogen Rocket engine that produces 6000K+ temperatures [...]

Lemme stop you there for three reasons...

The first is that we're talking about [liquid/slush/metallic] hydrogen as fuel for a fusion reactor, not a rocket. It doesn't matter how dense the fuel material is, you will never get more than 0.42 MeV out of a H1-H1 fusion reaction unless you can produce the fusion reaction at a temperature/pressure sufficient to exploit either the proton-proton chain or CNO chain. Apples and oranges, man.

The second is that the only paper on the subject I've been able to locate (here) makes no bones about those figures being purely theoretical and the math to validate their assumptions is noticeably absent.

The third is that you're trying to compare two different forms of energy release... combustion vs. dissociation. Again, apples and oranges.

*Flag on the play. Moving goalposts*
Wait a second. So now your claiming that NO fusion will work. If SLMH doesn't work, HS doesn't work either. At which point we are left with either arguing that the canon is wrong and that they don't really have fusion engines, OR assuming that some sort of improvement has been made and that hydrogen fusion works.
You cant have it both ways, either H-H fusion works for both HS and SLMH or it doesn't work for both. You don't get to just claim that your favored fusion works because of super science and that all other fusions don't.

And since HG has explicitly said that these craft use fusion engines there is literally no room to argue that point. Ergo the only question becomes what kind of fusion engine, and what fuel does that use.

And THAT is where SLMH v. HS comes into play, when trying to figure out why you would pick one Hydrogen fuel over another Hydrogen fuel.

[Seto Kaiba]

*Flag on the play. Moving goalposts*

*blows whistle* Technical foul, unsportsmanlike conduct on the part of the straw man.

Wait a second. So now your claiming that NO fusion will work.

False. My argument from the beginning has been that SLMH is not necessary to achieve the results described.

SLMH offers no benefit over any other form of hydrogen in terms of the amount of energy released during fusion per unit of mass, and under any basic estimation of the physics involved requires significantly more energy to produce.

Your premise that an equivalent of greater amount of energy to the H1-B11 reaction is necessary to produce equivalent or greater thrust is dependent on a hasty generalization of all turbine designs (military and commercial) being created equal.

At which point we are left with either arguing that the canon is wrong and that they don't really have fusion engines, OR assuming that some sort of improvement has been made and that hydrogen fusion works.
You cant have it both ways, either H-H fusion works for both HS and SLMH or it doesn't work for both. You don't get to just claim that your favored fusion works because of super science and that all other fusions don't.

That would be a valid point if that were anything even remotely resembling my argument... but, of course, this is a straw man you set up to knock down instead.

That these craft use fusion engines is indisputable. That a fusion-powered fighter would require metallic hydrogen fuel to produce the levels of performance and endurance described in the RPG is not supported by the evidence.



EDIT: As we're not really getting anywhere with this topic anymore, it's probably best for us to both step back from this one before a mod is prompted to lock it. To that end, I'm going to tentatively make this my final public post on the matter. We can pick it up via PM if you'd like.

[ShadowLogan]

Lemme stop you there for three reasons...

Re: Point 1 & 3. I do not dispute that you are only going to be able to get X-amount of energy from a fusion reaction, but in the fuel's raw form, the energy density of H2 in its various states is not the same (that is all I am saying) it only differs at the application level that the energy release is different.

It does occur to me though, that SLMH might have some advantage over L/Slush-H2 not at the end product level (energy output of the fusion reaction), but in the preceding stage(s) of the reactor's operation. Ex: SLMH might have simply been chosen for its physical density, since it requires less volume for the same amount of mass as H2 in another state. Ex2: the dissociation's release of energy into another state to the required temperatures in plasma for fusion, might require less input of energy using SLMH vs L/Slush-H2.

Re: Pt2. That is the material I'm thinking of specifically. I know it is theoretical work. I'm not sure what you mean by the math is missing.

[Alrik Vas]

How much more dense is SLMH than SH? Would it really be that much better if you're cutting a few inches of volume off the fuel tanks?

[eliakon]

How much more dense is SLMH than SH? Would it really be that much better if you're cutting a few inches of volume off the fuel tanks?

It is about 10x the density.
So for every cubic inch of SLMH you are replacing 10 cubic inches of SH.
Or put another way to store the same weight in fuel a SLMH tank is 1/10th the size of a SH tank.

[glitterboy2098]

How much more dense is SLMH than SH? Would it really be that much better if you're cutting a few inches of volume off the fuel tanks?

It is about 10x the density.
So for every cubic inch of SLMH you are replacing 10 cubic inches of SH.
Or put another way to store the same weight in fuel a SLMH tank is 1/10th the size of a SH tank.

which is good because SLMH is not cryogenic, that is, it doesn't have to be cooled down to super low temps the way slush hydrogen does. which means in addition to being 10 times bulkier slush hydrogen requires massively more bulky systems built into the fuel tank to keep it cold (think like a refridgerator but hundreds of times colder.. the tank has to be built with special insulation to keep the heat out, has to be lined with tubes circulating even colder liquids to suck heat way, etc)

[Jefffar]

How much more dense is SLMH than SH? Would it really be that much better if you're cutting a few inches of volume off the fuel tanks?

It is about 10x the density.
So for every cubic inch of SLMH you are replacing 10 cubic inches of SH.
Or put another way to store the same weight in fuel a SLMH tank is 1/10th the size of a SH tank.

which is good because SLMH is not cryogenic, that is, it doesn't have to be cooled down to super low temps the way slush hydrogen does. which means in addition to being 10 times bulkier slush hydrogen requires massively more bulky systems built into the fuel tank to keep it cold (think like a refridgerator but hundreds of times colder.. the tank has to be built with special insulation to keep the heat out, has to be lined with tubes circulating even colder liquids to suck heat way, etc)

And, as there are no flamable vapours, the storage is also less dangerous and more resistant to battle damage.


Basically, even if it produced no greater energy per kg than Slush Hydrogen, SLMH is a superior fuel in terms of energy per litre and handling qualities.

[Alrik Vas]

But much more energy intensive to make, it would seem.

[eliakon]

But much more energy intensive to make, it would seem.

True. But since you make it ahead of time that's not a huge issue.
It would be like noting that Composition B is more energy intensive to make than Black Powder....and than extrapolating that since this is the case militaries would stick to using Black Power since it is easier to make.

[glitterboy2098]

But much more energy intensive to make, it would seem.

to get it made yes.. roughly (tricky to compare between cooling something to 14 degrees above absolute zero and putting it under intense pressures equal to thousands of atmospheres)

but slush hydrogen requires the same amount of energy to be expended constantly to keep it slush. remove it from the cooling system and it turns back into a gas quite rapidly. if the cooling fails you quickly get empty tanks (because hydrogen gas can actualyl slip through between the gaps in molecules.. the gas always leaks out)

while SLMH stays the way it is once that pressure is released, and afterwards is just a very flammable liquid than can be stored not to different than jet fuel.. in cans, drums, sitting around in ambient temps and pressures. no energy required to store it.

[Jefffar]

But much more energy intensive to make, it would seem.

to get it made yes.. roughly (tricky to compare between cooling something to 14 degrees above absolute zero and putting it under intense pressures equal to thousands of atmospheres)

but slush hydrogen requires the same amount of energy to be expended constantly to keep it slush. remove it from the cooling system and it turns back into a gas quite rapidly. if the cooling fails you quickly get empty tanks (because hydrogen gas can actualyl slip through between the gaps in molecules.. the gas always leaks out)

while SLMH stays the way it is once that pressure is released, and afterwards is just a very flammable liquid than can be stored not to different than jet fuel.. in cans, drums, sitting around in ambient temps and pressures. no energy required to store it.

Actually, since it wouldn't evaporate as posited earlier, it'd be safer and easier to store than conventional fuels as you wouldn't have to prevent evaporation or deal with potentially explosive vapours.

[Seto Kaiba]

It does occur to me though, that SLMH might have some advantage over L/Slush-H2 not at the end product level (energy output of the fusion reaction), but in the preceding stage(s) of the reactor's operation. Ex: SLMH might have simply been chosen for its physical density, since it requires less volume for the same amount of mass as H2 in another state. Ex2: the dissociation's release of energy into another state to the required temperatures in plasma for fusion, might require less input of energy using SLMH vs L/Slush-H2.

Example 2 is an interesting thought... though that would depend on the type of reactor you were using. In a magnetic confinement fusion reactor that might actually be a significant asset, but from the very brief descriptions of the reactor-engine arrangements in the RPG it seems like they're using inertial confinement fusion. You don't want your reactant explosively cooking off prior to being heated to the fusion threshold by the lasers (or ion beams).

And, as there are no flamable vapours, the storage is also less dangerous and more resistant to battle damage.

Basically, even if it produced no greater energy per kg than Slush Hydrogen, SLMH is a superior fuel in terms of energy per litre and handling qualities.

Actually, there's one risk with storing SLMH that is much, MUCH greater than storing slush or liquid hydrogen. If the tank it hit by a weapon that causes thermal effects, you have a much greater explosion risk than with liquid or slush hydrogen. The cryogenic fuel can more readily disperse the heat from the strike, and even if you push it to the dissociation threshold it doesn't release nearly as much energy. Hit the metallic hydrogen tank with a similar strike carrying enough heat or electrical energy, and you basically turn the entire fuel tank into a massive high-energy bomb.

But much more energy intensive to make, it would seem.

to get it made yes.. roughly (tricky to compare between cooling something to 14 degrees above absolute zero and putting it under intense pressures equal to thousands of atmospheres)

That's inaccurate. Production of slush hydrogen typically entails drawing a vacuum on the fuel production vessel while cooling it to about 14 kelvin. (See page 3 of this document.)

While it does need to be kept cold, there's a fair amount of flexibility in the amount of tank/line pressure.

It's metallic hydrogen that requires the vast input of pressure to produce... millions of atmospheres, normally, though there is a significant amount of debate as to the conditions best suited for its production. (The expected range is 3.2 million atmospheres or more, though some experiments have claimed to produce it at about 2.6 million atmospheres.)

Actually, since it wouldn't evaporate as posited earlier, it'd be safer and easier to store than conventional fuels as you wouldn't have to prevent evaporation or deal with potentially explosive vapours.

As noted earlier in the thread, you still need to observe special fuel handling practices because the fuel's ignition energy is a LOT lower than gasoline or jet fuel. You would still need to observe a lot of the same fuel handling protocols in AIAA G-095-2004 and NSS 1740.16.

[eliakon]

And, as there are no flamable vapours, the storage is also less dangerous and more resistant to battle damage.

Basically, even if it produced no greater energy per kg than Slush Hydrogen, SLMH is a superior fuel in terms of energy per litre and handling qualities.

Actually, there's one risk with storing SLMH that is much, MUCH greater than storing slush or liquid hydrogen. If the tank it hit by a weapon that causes thermal effects, you have a much greater explosion risk than with liquid or slush hydrogen. The cryogenic fuel can more readily disperse the heat from the strike, and even if you push it to the dissociation threshold it doesn't release nearly as much energy. Hit the metallic hydrogen tank with a similar strike carrying enough heat or electrical energy, and you basically turn the entire fuel tank into a massive high-energy bomb.

So what is the flammability/explosion hazard of pure gaseous hydrogen? (Since HS that loses its cooling, or presureization quickly boils away into gas)

But much more energy intensive to make, it would seem.

to get it made yes.. roughly (tricky to compare between cooling something to 14 degrees above absolute zero and putting it under intense pressures equal to thousands of atmospheres)

That's inaccurate. Production of slush hydrogen typically entails drawing a vacuum on the fuel production vessel while cooling it to about 14 kelvin. (See page 3 of this document.)

While it does need to be kept cold, there's a fair amount of flexibility in the amount of tank/line pressure.

I was pretty sure that the papers said that HS had to be keep at a precise pressure point or it boiled/froze.

It's metallic hydrogen that requires the vast input of pressure to produce... millions of atmospheres, normally, though there is a significant amount of debate as to the conditions best suited for its production. (The expected range is 3.2 million atmospheres or more, though some experiments have claimed to produce it at about 2.6 million atmospheres.)

Where are you getting these numbers? The experimental data has a wide range of pressures/conditions needed. Since the experimental science on this is still in the initial phases no one has proved the exact pressure/conditions needed. This means that the pressure could still be as low as the original predictions of 25gpa and not 260gpa.
No one doubts that it will take pressurization to make, but inflating the required pressure by a factor of 10 doesn't prove anything about how hard it is to actually make, nor does choosing to engage in speculation about the needed factors.
This is very important since lithium doping has been suggested to reduce the pressure, and other forms of alterations have also been put forth. Since we do not know the molecular make up of SLHM it is hard to speculate on if it was doped, and if so, with what.

Actually, since it wouldn't evaporate as posited earlier, it'd be safer and easier to store than conventional fuels as you wouldn't have to prevent evaporation or deal with potentially explosive vapours.

As noted earlier in the thread, you still need to observe special fuel handling practices because the fuel's ignition energy is a LOT lower than gasoline or jet fuel. You would still need to observe a lot of the same fuel handling protocols in AIAA G-095-2004 and NSS 1740.16.

Interesting...where are you getting this information on the ignition energy and explosiveness of SLMH? Since I am not familiar with any experiments on the flammability of any sort of MH let alone whatever SLMH is.....this sounds more like an unsupported opinion rather than an actual fact.

[Jefffar]

Seto, you are incorrect about that.

Flammable liquids don't burn. It's the vapour given off by the liquid that ignites. The temperature of the burning vapour then vapourizes more of the liquid providing more fuel for the flames. For some liquids (ie Gasoline) this can happen explosively.

However, the vapour doesn't burn on its own, it needs another chemical (typically oxygen in the case of hydrogen burning) for the reaction to be sustained. This is why shooting a full tank of gas with incendiary ammunition doesn't set it off, but a three-quarters empty tank will burn easily.

Since SLMH doesn't evaporate (as posited above) there is no vapour cloud without some kind of mechanical assistance (similar to a fuel injector or carburetor) so raw heat or electricity shouldn't set it off any more readily than LH or SH. Indeed, it should be more resistant to being set off as both of those can vaporize easily.

Not to forget, the total explosive energy of a tank of SLMH and a tank of SH is going to be equal if the total mass of the fuel is equal. So setting off a mass of SH is going to be just as catastrophic as setting off an equal mass of SLMH, it's just that the SLMH can be stored in a smaller tank, which makes it harder to set off for a couple of reasons.

First, as the smaller tank empties, there is a smaller void. A smaller void means less room for a vapour (if one is somehow created) and less room for an oxidizer to fuel the burn/explosion.

Secondly, the smaller fuel tank for SLMH would be harder to score a direct hit on and easier to armour than the larger tank. Being harder to hit and better protected goes a long way to preventing an explosion.

[Seto Kaiba]

So what is the flammability/explosion hazard of pure gaseous hydrogen? (Since HS that loses its cooling, or presureization quickly boils away into gas)

The ignition level should be roughly the same, the difference being that the energy released by combustion is much less...

I was pretty sure that the papers said that HS had to be keep at a precise pressure point or it boiled/froze.

The paper I linked in that post indicated there were several atmospheres of pressure worth of leeway for storage and transfer, and that was a report from NASA's lab specifically on the production, storage, and transfer of bulk quantities of slush hydrogen fuel.

Where are you getting these numbers? The experimental data has a wide range of pressures/conditions needed. Since the experimental science on this is still in the initial phases no one has proved the exact pressure/conditions needed. This means that the pressure could still be as low as the original predictions of 25gpa and not 260gpa.

Lawrence Livermore University's testing cited 140GPa, Cornell and the Commissariat à l'énergie atomique et aux énergies alternatives were still having difficulty getting the band gap to true metallicity at 320GPa+, Harvard's study indicated 260GPa+... I could go on. I have been unable to find any actual experiment in producing non-doped metallic hydrogen that used less than 1.38 million atmospheres of pressure.

Interesting...where are you getting this information on the ignition energy and explosiveness of SLMH? Since I am not familiar with any experiments on the flammability of any sort of MH let alone whatever SLMH is.....this sounds more like an unsupported opinion rather than an actual fact.

I linked to the article on the reactiveness of metallic hydrogen earlier in my reply to ShadowLogan, I found a matching article on ntrs.nasa.gov as well. The ignition energy of hydrogen in the presence of oxygen is a known property of the element.

Since SLMH doesn't evaporate (as posited above) there is no vapour cloud without some kind of mechanical assistance (similar to a fuel injector or carburetor) so raw heat or electricity shouldn't set it off any more readily than LH or SH. Indeed, it should be more resistant to being set off as both of those can vaporize easily.

Unless you've found a magical way to turn off thermodynamics, there's no such thing as a truly vaporless fluid... so you still have to be concerned about the 0.02 millijoule ignition energy. There's less danger if it's liquid at STP, but you still need to worry about the vapor and static sparking (esp. during refueling operations). Being stable in a liquid state does not magically make it safe... recall that this IS essentially rocket fuel.

Not to forget, the total explosive energy of a tank of SLMH and a tank of SH is going to be equal if the total mass of the fuel is equal. So setting off a mass of SH is going to be just as catastrophic as setting off an equal mass of SLMH, it's just that the SLMH can be stored in a smaller tank, which makes it harder to set off for a couple of reasons.

The dissociation energy threshold is the one you have to worry about as far as tank damage in combat... because in space you're not going to have oxygen for a combustion explosion. Metallic hydrogen releases a LOT more energy in dissociation because of its higher density.

[eliakon]

So what is the flammability/explosion hazard of pure gaseous hydrogen? (Since HS that loses its cooling, or presureization quickly boils away into gas)

The ignition level should be roughly the same, the difference being that the energy released by combustion is much less...

So no, you don't know the numbers for either of these nor how they compare. Got it.

I was pretty sure that the papers said that HS had to be keep at a precise pressure point or it boiled/froze.

The paper I linked in that post indicated there were several atmospheres of pressure worth of leeway for storage and transfer, and that was a report from NASA's lab specifically on the production, storage, and transfer of bulk quantities of slush hydrogen fuel.

Since it says that the HS has to be made and kept at precisely the Triple Point of Hydrogen that seems to be the opposite of 'has leeway' Can you point me to the exact page/paragraph where it talks about this leeway?

Since SLMH doesn't evaporate (as posited above) there is no vapour cloud without some kind of mechanical assistance (similar to a fuel injector or carburetor) so raw heat or electricity shouldn't set it off any more readily than LH or SH. Indeed, it should be more resistant to being set off as both of those can vaporize easily.

Unless you've found a magical way to turn off thermodynamics, there's no such thing as a truly vaporless fluid... so you still have to be concerned about the 0.02 millijoule ignition energy. There's less danger if it's liquid at STP, but you still need to worry about the vapor and static sparking (esp. during refueling operations). Being stable in a liquid state does not magically make it safe... recall that this IS essentially rocket fuel.

Okay I'll bite, where are you getting the evaporation rate of SLMH and the ignition point of MH (Hydrogen GAS has an ignition point of .02millijoules...so that would, for instance cover the vapors that outgas from HS),

Not to forget, the total explosive energy of a tank of SLMH and a tank of SH is going to be equal if the total mass of the fuel is equal. So setting off a mass of SH is going to be just as catastrophic as setting off an equal mass of SLMH, it's just that the SLMH can be stored in a smaller tank, which makes it harder to set off for a couple of reasons.

The dissociation energy threshold is the one you have to worry about as far as tank damage in combat... because in space you're not going to have oxygen for a combustion explosion. Metallic hydrogen releases a LOT more energy in dissociation because of its higher density.

What is this 'dissociation energy threshold' of which you speak?
The only Dissociation Energy I can find reference to relates to breaking atomic bonds. Since there are no atomic bonds in MH I am curious where this 'explosion' is coming from.

<EDIT>
I am curious about something

That makes even less sense than the above... reflex cannons are canonically particle beam weapons, gravity would be useless as a way of focusing the beam.

Where is it stated in canon what a reflex cannon is? I would love to be able to cite this for my gaming group as it has relevance to game operation.

[Jefffar]

Also, as particles have mass, and mass is subject to gravitational forces, wouldn't gravity controlling devices be a plausible focussing method?

[glitterboy2098]

Also, as particles have mass, and mass is subject to gravitational forces, wouldn't gravity controlling devices be a plausible focussing method?

Einstein and hawking would agree with you. gravity effects all things.. matter and energy, regardless of whether it has mass or not. this is why we gets stuff like gravitational lensing (where the gravity of an object alters the course of light (a massless particle/wave duality.) it is also why we see things like black holes.. not even light can escape because gravity is so high.

gravity is the warping of space remember. anything that exists in space-time will be effected by gravity. and anything that does not exist in spacetime can't interact with our universe at all and thus might as well not exist.

[guardiandashi]

Also, as particles have mass, and mass is subject to gravitational forces, wouldn't gravity controlling devices be a plausible focussing method?

Einstein and hawking would agree with you. gravity effects all things.. matter and energy, regardless of whether it has mass or not. this is why we gets stuff like gravitational lensing (where the gravity of an object alters the course of light (a massless particle/wave duality.) it is also why we see things like black holes.. not even light can escape because gravity is so high.

gravity is the warping of space remember. anything that exists in space-time will be effected by gravity. and anything that does not exist in spacetime can't interact with our universe at all and thus might as well not exist.

nitpick photons actually do have mass. Its very small and under basic physics they have a rest mass that very closely approximates (or equals) zero, however they do have a relativistic mass based upon their frequency.

[Jefffar]

Since SLMH doesn't evaporate (as posited above) there is no vapour cloud without some kind of mechanical assistance (similar to a fuel injector or carburetor) so raw heat or electricity shouldn't set it off any more readily than LH or SH. Indeed, it should be more resistant to being set off as both of those can vaporize easily.

Unless you've found a magical way to turn off thermodynamics, there's no such thing as a truly vaporless fluid... so you still have to be concerned about the 0.02 millijoule ignition energy. There's less danger if it's liquid at STP, but you still need to worry about the vapor and static sparking (esp. during refueling operations). Being stable in a liquid state does not magically make it safe... recall that this IS essentially rocket fuel.

Actually the point that SLMH doesn't evaporate isn't mine, it was made above, I'm just following up on that.

And what you're indicating doesn't make it any more dangerous than LH or SH, both of which should have about the same energy per unit mass. SLMH just lets it be stored in a smaller package.

Not to forget, the total explosive energy of a tank of SLMH and a tank of SH is going to be equal if the total mass of the fuel is equal. So setting off a mass of SH is going to be just as catastrophic as setting off an equal mass of SLMH, it's just that the SLMH can be stored in a smaller tank, which makes it harder to set off for a couple of reasons.

The dissociation energy threshold is the one you have to worry about as far as tank damage in combat... because in space you're not going to have oxygen for a combustion explosion. Metallic hydrogen releases a LOT more energy in dissociation because of its higher density.

My understanding is the disassociation energy isn't related to density, but to the chemical composition of the molecule. So hydrogen-hydrogen bonds should have the same amount of energy be they SLMH, SH or LH. The only difference here is the greater density means you have the same amount of energy in a much smaller (and therefore harder to hit and damage) fuel system.

What I'm seeing here is that SLMH is no more dangerous than other hydrogen-based fuels, but provides a greater energy per litre and is safer to store and handle. If we assume that economical production of SMH is within the technological capabilities of a society that is demonstrably capable of inter-planetary space travel, high out put energy weapons, compact fusion power plants, transformable robot aerospace fighters and artificially intelligent soda vending machines then its hard to find a reason for using any other available fuel type for mecha and similar other than possibly some sort of magical alien plant juice derivative.

[Seto Kaiba]

For clarity's sake, I'm splitting the various questions aimed at me into two replies.

I am curious about something

That makes even less sense than the above... reflex cannons are canonically particle beam weapons, gravity would be useless as a way of focusing the beam.

Where is it stated in canon what a reflex cannon is? I would love to be able to cite this for my gaming group as it has relevance to game operation.

The Infopedia page for the SDF-1 has a parenthetical note on the armament line item for the reflex cannon which explicitly identifies it as a "heavy particle beam" weapon.

The Tirolian Mothership entry also identifies the reflex cannon as being a heavy particle beam weapon in exactly the same fashion as the SDF-1 entry.

Almost all shipboard energy weaponry in the Robotech.com Infopedia is identified as particle beam weaponry in the Infopedia, but there was one interesting aberration of note that I found while I was digging out the links for you. The Infopedia Mecha Database article for the Tirolian Heavy Cruiser gives the ship a battery of four reflex cannons and identifies them as "electromagnetic fusion beam" weapons in the armaments entry, but refers to them as "bombardment fusion cannons" instead of "reflex cannons" in the vessel's description.[sup]1[/sup]

The RPG's Macross Saga sourcebook declines to identify the nature of a reflex cannon in the SDF-1's writeup, but the write-up of the Masters' motherships in the Masters Saga sourcebook (pg251 of the manga size) identifies the Masters' reflex cannons (and those of the SDF-1 and SDF-3, presumably pre-retrofit in the latter's case) as being a form of "particle acceleration weapon".

Also, as particles have mass, and mass is subject to gravitational forces, wouldn't gravity controlling devices be a plausible focussing method?

The gravity wells of large stellar objects like planets, moons, and stars are capable of bending light... but the mass of elementary particles is so low that it would be a wildly inefficient method of doing so compared to using electromagnetic fields, which can be used to both focus the beam and provide acceleration at the same time. (This is basically how every particle accelerator works.)

Reflex furnaces. the Canon comic "Invasion" with its mars base sera sidestory confirms reflex furnaces as well.. the zentreadi detect one on mars, built to similar specs as the SDF-1's, and investigate in such a way to trigger a shooting incident. the base commander then uses a prototype reflex cannon to destroy the zent ship. the reflex cannon is described as a human development. they couldn't duplicate the SDF-1's twin boom design, but found a way to draw extra power from the gravitational field of a planet to boost the yield, and their design uses gravity generators to shape the beam and release it in one "synchronous" burst.

On reflection, I strongly suspect this is Tommy drawing connections to the OSM and missing a couple connections along the way.

The OSM version of what Robotech calls "reflex cannons" did use gravitational manipulation via fold technology as part of the firing mechanism (see below), and the Grand Cannons and other high-angle beam guns used a focused spatial distortion to aim the guns in lieu of a turret mount, redirecting the beam by bending the space in front of the barrel with an effect not dissimilar to pin-point barrier technology.

(Of course, in Robotech, "reflex cannons" are simply particle beam guns of extraordinary size and the barriers are just sci-fi generic shielding rather than a focused distortion of space-time... but you see where Tommy and co. were probably going with this.)



1. This may be a legacy of the uRRG and OSM sources that was never corrected in the Infopedia when the other examples of reflex weaponry were identified as particle weapons.

In the Macross OSM, almost all ship-mounted energy weaponry belongs to a class of weapons called super dimension energy cannons. These weapons are based on fold technology, and operate by pulling superdense matter from the 10+ dimensional sub-universe called super dimension space into the three-dimensional universe. The mass of that super-dense matter (also known as "heavy quanta") is such that, when drawn into realspace, it "crushes" three-dimensional space so hard that the heavy quanta fuse, releasing a huge amount of energy in the process. The end result is an enormously powerful fusion plasma beam. (This piece of technology is described in brief in Macross Perfect Memory pg.60-62, and in greater depth in more technically-focused books like Macross Chronicle, on Technology Sheet 13A "Dimension weapons")

[eliakon]

For clarity's sake, I'm splitting the various questions aimed at me into two replies.

I am curious about something

That makes even less sense than the above... reflex cannons are canonically particle beam weapons, gravity would be useless as a way of focusing the beam.

Where is it stated in canon what a reflex cannon is? I would love to be able to cite this for my gaming group as it has relevance to game operation.

The Infopedia page for the SDF-1 has a parenthetical note on the armament line item for the reflex cannon which explicitly identifies it as a "heavy particle beam" weapon.

The Tirolian Mothership entry also identifies the reflex cannon as being a heavy particle beam weapon in exactly the same fashion as the SDF-1 entry.

Almost all shipboard energy weaponry in the Robotech.com Infopedia is identified as particle beam weaponry in the Infopedia, but there was one interesting aberration of note that I found while I was digging out the links for you. The Infopedia Mecha Database article for the Tirolian Heavy Cruiser gives the ship a battery of four reflex cannons and identifies them as "electromagnetic fusion beam" weapons in the armaments entry, but refers to them as "bombardment fusion cannons" instead of "reflex cannons" in the vessel's description.[sup]1[/sup]

The RPG's Macross Saga sourcebook declines to identify the nature of a reflex cannon in the SDF-1's writeup, but the write-up of the Masters' motherships in the Masters Saga sourcebook (pg251 of the manga size) identifies the Masters' reflex cannons (and those of the SDF-1 and SDF-3, presumably pre-retrofit in the latter's case) as being a form of "particle acceleration weapon".

Okay, that is interesting, I will agree Reflex Beam weapons appear to be heavy particle beams.

Also, as particles have mass, and mass is subject to gravitational forces, wouldn't gravity controlling devices be a plausible focussing method?

The gravity wells of large stellar objects like planets, moons, and stars are capable of bending light... but the mass of elementary particles is so low that it would be a wildly inefficient method of doing so compared to using electromagnetic fields, which can be used to both focus the beam and provide acceleration at the same time. (This is basically how every particle accelerator works.)

Um you do realize that the mass of the elementary particle has no effect on if it will be affected by outside gravity right?
And since we know that
1) officially some sort of gravity system was involved in these
2) there is no known way to project an electromagnetic field (you can have one inside your magnets, but not outside....meaning that to do so will require rubber-science of some kind anyway)

it seems likely that they simply chose to make gravity the chosen rubber.

Reflex furnaces. the Canon comic "Invasion" with its mars base sera sidestory confirms reflex furnaces as well.. the zentreadi detect one on mars, built to similar specs as the SDF-1's, and investigate in such a way to trigger a shooting incident. the base commander then uses a prototype reflex cannon to destroy the zent ship. the reflex cannon is described as a human development. they couldn't duplicate the SDF-1's twin boom design, but found a way to draw extra power from the gravitational field of a planet to boost the yield, and their design uses gravity generators to shape the beam and release it in one "synchronous" burst.

On reflection, I strongly suspect this is Tommy drawing connections to the OSM and missing a couple connections along the way.

It sort of doesn't matter what you suspect was done. The simple fact of the matter is that the canon says that they used gravity ergo gravity was used.

The OSM version of what Robotech calls "reflex cannons" did use gravitational manipulation via fold technology as part of the firing mechanism (see below), and the Grand Cannons and other high-angle beam guns used a focused spatial distortion to aim the guns in lieu of a turret mount, redirecting the beam by bending the space in front of the barrel with an effect not dissimilar to pin-point barrier technology.

And since there is nothing at all to suggest that the Grand Cannon did NOT use its already-established-to-exist gravity systems in its aiming (which as pointed out allows for the observed beam effect)

(Of course, in Robotech, "reflex cannons" are simply particle beam guns of extraordinary size and the barriers are just sci-fi generic shielding rather than a focused distortion of space-time... but you see where Tommy and co. were probably going with this.)

And the source for this claim about the shields?
Especially since AFAIK there is no discussion at all about the mechanics of the shield system, or how it works. Just that it is some sort of energy shield.

[ShadowLogan]

(Of course, in Robotech, "reflex cannons" are simply particle beam guns of extraordinary size and the barriers are just sci-fi generic shielding rather than a focused distortion of space-time... but you see where Tommy and co. were probably going with this.)

I am not sure that the "generic shielding" applies 100% of the time since dialogue for the Pin Point Barrier system in Ep6 is connected with a "reaction" that generated from a "distortion" in space-time when the Fold Generators disappeared. How much of that works for the Omni-Barrier and others I don't know since they don't get discussed like that w/n the show AFAIK, but it does appear that distortions in space-time are connected with at least some RT barriers.

The second is that the only paper on the subject I've been able to locate (here) makes no bones about those figures being purely theoretical and the math to validate their assumptions is noticeably absent.

Metallic Hydrogen is mentioned here in this article w/n a broader concept summary for "High Energy Density Materials" (I've also seen Matter): https://fas.org/spp/military/docops/usaf/2020/app-i.htm

They list Metallic Hydrogen with an Isp of 1800seconds (a bit higher than first), but other wise don't really get into it much.

I would also remind you that according to theory doping the H2 with another material (Lithium was the example IIRC) can theoretically reduce the required pressure.