Super Macross Mecha Fun Time Discussion Thread!

[pengbuzz]

31 minutes ago, Seto Kaiba said:

I dunno, per the old material I translated the ARMD-class was designed to withstand some pretty intense acceleration stresses... and being shielded from the impact by a portable immovable object made out of twisted-up space-time means the ship doesn't have to deal with any of the physical consequences of the impact.  The barrier's basically a wall made of twisted space holding a relative position from the ship, so it wouldn't be pushed around by the impact because it's not a physical object.

Okay, thanks for the clarification Seto. I wondered about that for some time now...

[Sir Galahad®]

Does the EX-Gear transforming as your pilot seat assist in withstanding the high G-Forces? If it does, are there some sort of technical information about it?

[Seto Kaiba]

10 hours ago, Sir Galahad® said:

Does the EX-Gear transforming as your pilot seat assist in withstanding the high G-Forces? If it does, are there some sort of technical information about it?

It helps, but the primary anti-G mechanism in the 5th Generation Valkyries is the Inertia Store Converter (Inertia Capacitor).

Essentially, the EX-Gear pilot seat acts as a movable seat that automatically adjusts the pilot's posture in various ways to reduce the tendency of blood to pool in the extremities and slightly cushion the impact of acceleration to enable the pilot to function better under g-loads.

(The VF-19's pilot seat did something similar, though primarily against lateral g-forces via rotation.)

[marthf1]

The Macross 7 Dynamite OP has a whole sequence showing an assembling of a VF-19 starting with, visually, traditional jet engines. Of course things are not always as depicted, but Is there any information available to indicate how (typical? standard?) it is as a representation of a VF's engines?

Some initial pondering made me think there would be less traditional aspects given the overtechnology thermonuclear reaction engine & other applicable overtechnology, especially if there were space-focused models might not bother with atmospheric capabilities. Now, to begin some rambling:

 

When searching up the VF-1 technical sheets, since I recall seeing some before, & finding some on mecha journal (hopefully the images on this topic correspond to official versions, some of which seem to be in the Valkyrie Cut Away from Movie Artbook thread - which has an interesting discussion on the compressor stages that died out due to the lack of, presumably, series technical data), the various cutaways appear to trend in that direction. The engine core has been substituted, the exhaust section is not just an open duct, there's a pre-compressor stage as a module due to how nearly all VF legs are designed, & what it claimed to be geometry shift for a FF-2001 to operate in RAM/SCLAM jet mode.

On the hand, the external engine views indicate little is different other than length, being in two modules, &, well, the VF-1 is a far cry from the VF-19 which is vastly different from the YF-30....

One of the Q&A threads mentioned the series has been increasingly less willing to create or release this type of information since around the Frontier era & that the Delta era is absolutely anemic, so perhaps the YF-24 & later will be more speculation than not. Though there are some FF-3001/FC1 Stage II details with significant differences that I recall being mentioned, although those probably wouldn't affect their visual representation much.

Presumably, then, things in the Plus/7 era might have some hints? The Zero era might not have much new since those were stated to be overtuned standard modern jet engines. Oh, but it seems there still is a separate compressor module since it's visible right at the intakes & the leg transformation is the same? In that respect, wouldn't it be the same for the VF-19 & the rest that have that setup? Hmm, upon examining the OP more closely, maybe the VF-19 engines do have a separate compressor module, but have it connected to the main section with that accordion section.

Argh, maybe it's as simple as there being no reason to reinvent the wheel....

[Seto Kaiba]

4 hours ago, marthf1 said:

The Macross 7 Dynamite OP has a whole sequence showing an assembling of a VF-19 starting with, visually, traditional jet engines. Of course things are not always as depicted, but Is there any information available to indicate how (typical? standard?) it is as a representation of a VF's engines?

As drawn in the Macross Dynamite 7 OP, no... those engines are drawn much too large.

Of course, it could easily be dismissed as artistic license either in or out of universe, since those are holograms for a public concert... not exactly a place where you'd show a true 3D representation of a state-of-the-art military aircraft engine.

 

 

4 hours ago, marthf1 said:

When searching up the VF-1 technical sheets, since I recall seeing some before, & finding some on [REDACTED] [...]

Let's never mention that page again.

EDIT: Let's just say, it's a very bad website that contains a lot of misinformation... this space previously held a bit of a rant about my views on that matter.

 

 

4 hours ago, marthf1 said:

The engine core has been substituted, the exhaust section is not just an open duct, there's a pre-compressor stage as a module due to how nearly all VF legs are designed, & what it claimed to be geometry shift for a FF-2001 to operate in RAM/SCLAM jet mode.

On the hand, the external engine views indicate little is different other than length, being in two modules, &, well, the VF-1 is a far cry from the VF-19 which is vastly different from the YF-30....

 

When you get right down to it, the standard design of the thermonuclear reaction turbine engine that has remained essentially unchanged across the ~60 years of Variable Fighter designs in-universe is largely unmodified low-bypass turbofan jet engine.  The main differences being that the low-pressure compressor is decoupled from the engine body and is electrically driven, and the burner is replaced by high-temperature plasma exhaust from a compact thermonuclear reactor.

Minus the pre-/low-pressure compressor stage, the entire engine resides in the lower leg in the vast majority of VF models.  

Externally, there isn't a lot of visible difference from a conventional engine aside from the length... though that's because, externally, there's not a lot to an engine except various feed lines for coolant, fuel, lubricants, etc.  (On VFs, there's a certain degree of simplification as it's been indicated the cryogenic fuel slush is also used as a system coolant.)

 

 

4 hours ago, marthf1 said:

One of the Q&A threads mentioned the series has been increasingly less willing to create or release this type of information since around the Frontier era & that the Delta era is absolutely anemic, so perhaps the YF-24 & later will be more speculation than not. Though there are some FF-3001/FC1 Stage II details with significant differences that I recall being mentioned, although those probably wouldn't affect their visual representation much.

The amount of detail published in official setting materials has been declining somewhat, yes... though supplementary official setting publications and non-setting materials like the Master File series have seen less of a decline in that respect.  Nevertheless, at the very least there has been adequate detail about how various new generations of engine tech have differed from each other.

You are correct to assume the FF-3001/FC2 design changes don't affect its external appearance much... they're mostly internal design changes only to the parts of the engine that aren't moving parts, connected to the reactor, GIC, and plasma confinement.

 

 

4 hours ago, marthf1 said:

Presumably, then, things in the Plus/7 era might have some hints?

Not s'much, no.

 

 

4 hours ago, marthf1 said:

Oh, but it seems there still is a separate compressor module since it's visible right at the intakes & the leg transformation is the same? In that respect, wouldn't it be the same for the VF-19 & the rest that have that setup?

Yeah, the precompressor/low-pressure compressor is a common feature to virtually all engine designs.

Edited February 10, 2022 by Seto Kaiba

[aurance]

So what’s the deal with the very narrow exhausts (feet) in majority of the valks from -4 to -19 when they’re folded up for fighter mode? Wouldn’t that cause a lot of turbulence and compression of exhaust gases? Is that a thing you would want for some reason?

[Bolt]

I'm seeing a different launch arm set up, I believe it's from the digital mission VFX. Is what I'm seeing the launch or recovery ? 

I thought the launch was from a long ramp/boom from the stealth cruiser..

[Seto Kaiba]

52 minutes ago, aurance said:

So what’s the deal with the very narrow exhausts (feet) in majority of the valks from -4 to -19 when they’re folded up for fighter mode? Wouldn’t that cause a lot of turbulence and compression of exhaust gases? Is that a thing you would want for some reason?

I'll have to look into it and get back to you, since my brain is a bit fried at the moment due to fatigue... but if it's anything like a normal C-D nozzle flow compression is the point.  In normal operation, the converging nozzle increases the exhaust velocity and it can diverge to accommodate afterburner operation.

 

27 minutes ago, Bolt said:

I'm seeing a different launch arm set up, I believe it's from the digital mission VFX. Is what I'm seeing the launch or recovery ? 

I thought the launch was from a long ramp/boom from the stealth cruiser..

So, that appears to be the Valhalla III-type stealth special forces carrier setup... which is a handoff from a hangar gate like that one to a rotating inertial catapult system.  The fighter drops out of the body of the ship on an arm (for that purpose, this picture is technically upside-down) and is released after the catapult arm connects to it.  Then it's spun like it's on a centrifuge to build up launch speed before being released by the catapult arm.

[pengbuzz]

41 minutes ago, Seto Kaiba said:

I'll have to look into it and get back to you, since my brain is a bit fried at the moment due to fatigue... but if it's anything like a normal C-D nozzle flow compression is the point.  In normal operation, the converging nozzle increases the exhaust velocity and it can diverge to accommodate afterburner operation.

 

So, that appears to be the Valhalla III-type stealth special forces carrier setup... which is a handoff from a hangar gate like that one to a rotating inertial catapult system.  The fighter drops out of the body of the ship on an arm (for that purpose, this picture is technically upside-down) and is released after the catapult arm connects to it.  Then it's spun like it's on a centrifuge to build up launch speed before being released by the catapult arm.

I can only imagine the inside of the pilot's helmet after that one! Ewwwwwwwwwww....

[Bolt]

1 hour ago, Seto Kaiba said:

I'll have to look into it and get back to you, since my brain is a bit fried at the moment due to fatigue... but if it's anything like a normal C-D nozzle flow compression is the point.  In normal operation, the converging nozzle increases the exhaust velocity and it can diverge to accommodate afterburner operation.

 

So, that appears to be the Valhalla III-type stealth special forces carrier setup... which is a handoff from a hangar gate like that one to a rotating inertial catapult system.  The fighter drops out of the body of the ship on an arm (for that purpose, this picture is technically upside-down) and is released after the catapult arm connects to it.  Then it's spun like it's on a centrifuge to build up launch speed before being released by the catapult arm.

Thanks @Seto Kaiba yes that is an underside picture as i wanted some clue how it is mounted.  

[Seto Kaiba]

 

The launch is shown in reasonable detail in the OP...

 

1 hour ago, pengbuzz said:

I can only imagine the inside of the pilot's helmet after that one! Ewwwwwwwwwww....

's probably pretty clean... the human centrifuges used for g-force training are WAY WAY worse.  NASA's goes up to 20G!

[pengbuzz]

5 minutes ago, Seto Kaiba said:

 

The launch is shown in reasonable detail in the OP...

 

's probably pretty clean... the human centrifuges used for g-force training are WAY WAY worse.  NASA's goes up to 20G!

Ah.... guacamole.

[Bolt]

1 hour ago, Seto Kaiba said:

 

The launch is shown in reasonable detail in the OP...

 

's probably pretty clean... the human centrifuges used for g-force training are WAY WAY worse.  NASA's goes up to 20G!

I see.  Hadn't noticed that detail before. Thanks again!

[JB0]

2 hours ago, pengbuzz said:

I can only imagine the inside of the pilot's helmet after that one! Ewwwwwwwwwww....

Pilot's probably comfy the whole time. Hooray for inertial management systems! 

[sketchley]

6 hours ago, aurance said:

So what’s the deal with the very narrow exhausts (feet) in majority of the valks from -4 to -19 when they’re folded up for fighter mode? Wouldn’t that cause a lot of turbulence and compression of exhaust gases? Is that a thing you would want for some reason?

It's for the same reason that real world jet fighters have exhaust vanes: they compress the outflow to get greater speed at lower throttle settings.

The Macross era fighters you've mentioned were all designed when the F-22 Raptor was the big hot thing in aerospace news, thus a lot of those Valkyries emulate its thrust vectoring vanes.

There is, of course, artistic licence—Macross's fictional Otech allows for more heat resistant materials, thus enabling even more narrowing in the exhaust vanes.  However, some of what you're perceiving may just be the distortion caused from the 3/4 views that Kawamor-san tended to draw VFs at.  Also keep in mind that the top and bottom of a VF's thrust vectoring (feet) have dissimilar shapes, and that may be skewing our perception of how narrow (or not) the exhaust port may actually be.

 

As for turbulence... narrow, rectangular exhaust nozzles don't appear to negatively affect the F-22 in RL.  If there are any downsides to the shape, they appear to be outweighed by all the benefits those types of nozzles provide.

[aurance]

31 minutes ago, sketchley said:

It's for the same reason that real world jet fighters have exhaust vanes: they compress the outflow to get greater speed at lower throttle settings.

The Macross era fighters you've mentioned were all designed when the F-22 Raptor was the big hot thing in aerospace news, thus a lot of those Valkyries emulate its thrust vectoring vanes.

There is, of course, artistic licence—Macross's fictional Otech allows for more heat resistant materials, thus enabling even more narrowing in the exhaust vanes.  However, some of what you're perceiving may just be the distortion caused from the 3/4 views that Kawamor-san tended to draw VFs at.  Also keep in mind that the top and bottom of a VF's thrust vectoring (feet) have dissimilar shapes, and that may be skewing our perception of how narrow (or not) the exhaust port may actually be.

 

As for turbulence... narrow, rectangular exhaust nozzles don't appear to negatively affect the F-22 in RL.  If there are any downsides to the shape, they appear to be outweighed by all the benefits those types of nozzles provide.

It's not, it's mainly from me looking at the toys. The -0, -1, and all the -24 derivatives have a much more open design though.

So the answer seems to be, just artistic whims.

Edited February 11, 2022 by aurance

[Knight26]

3 hours ago, Seto Kaiba said:

 

The launch is shown in reasonable detail in the OP...

 

's probably pretty clean... the human centrifuges used for g-force training are WAY WAY worse.  NASA's goes up to 20G!

I would love to find a high res version of this, always thought it was awesome.

[Knight26]

9 minutes ago, aurance said:

It's not, it's mainly from me looking at the toys. The -0, -1, and all the -24 derivatives have a much more open design though.

So the answer seems to be, just artistic whims.

Incorrect.

As with real world aircraft that have 2-D thrust vectoring certain design concessions have to be made.  A slight constricting of the exhaust, using more thermally resistant materials, allows the thrust vector exhaust vanes to more easily, and precisely, maneuver the exhaust flow direction, though at the expense of higher maintenance costs.  There is a reason why most countries did not adopt 2-D thrust vectoring IRL.   Also, if you watched animation, particularly Macross Plus, there is a scene where the feet/TVC vanes extend during pre flight demonstrating that they do, in fact, open wider for full thrust/afterburner operations, as real world aircraft do.

Also, you have to realize that the toys are scale models of the designs, and as a result the thickness of the materials and parts, as well as their full degree of mobility, are not necessarily consistent with the VF's "Real World" design dimensions.

[sketchley]

1 hour ago, Knight26 said:

Also, you have to realize that the toys are scale models of the designs, and as a result the thickness of the materials and parts, as well as their full degree of mobility, are not necessarily consistent with the VF's "Real World" design dimensions.

I think there is one more thing that has to be addressed: what is the 'flight profile' of the toys/models/etc.?  Are they at rest?  (E.g. maximum constriction)  Full afterburner?  (E.g. least constriction)

Obviously we can't get inside the head of the designer or the engineering team that forced compromises on the positioning of those parts of the toys/models/etc. in that configuration due to materials limitations.  So my question is probably impossible to answer...

Edited February 11, 2022 by sketchley

[sketchley]

1 hour ago, Knight26 said:

I would love to find a high res version of this, always thought it was awesome.

I'm not sure if a higher res version even exists!  That animation in the original PS1 game AND the copy on the Macross 20th Anniversary DVD are marginally better, but not by much (I just checked my copy).  UNiT (the production studio) was really using some low quality compression when they made it back in 1997 to fit on the PS1's CD-ROMs.

Funny thing is the animations in VF-X2 are heads and shoulders higher in quality*, yet it was released only 2 years later in 1999 AND by the same production studio AND on the same CD-ROM format! 🤯

* where Digital Mission VF-X's is full of jaggies and compression artifacts, VF-X2's is pretty much analogue TV quality!

[aurance]

2 hours ago, Knight26 said:

Incorrect.

As with real world aircraft that have 2-D thrust vectoring certain design concessions have to be made.  A slight constricting of the exhaust, using more thermally resistant materials, allows the thrust vector exhaust vanes to more easily, and precisely, maneuver the exhaust flow direction, though at the expense of higher maintenance costs.  There is a reason why most countries did not adopt 2-D thrust vectoring IRL.   Also, if you watched animation, particularly Macross Plus, there is a scene where the feet/TVC vanes extend during pre flight demonstrating that they do, in fact, open wider for full thrust/afterburner operations, as real world aircraft do.

Also, you have to realize that the toys are scale models of the designs, and as a result the thickness of the materials and parts, as well as their full degree of mobility, are not necessarily consistent with the VF's "Real World" design dimensions.

Okay. I don’t think either of you are understanding what I’m saying. I’m already aware of the facts you two mentioned. And 'toys vary from real thing? Come on man, of course they do but that's not what I'm referring to. Let me try to add a drawing.

Seems like a deliberate change in design but my question was whether this was an in-world thing or just style. I guess we don't know. I should have clarified what I was pointing out.

Edited February 11, 2022 by aurance

[sketchley]

We get what you're saying (refer to my comments on the F-22 above).

Those side on images are also a bit misleading.  Inside, the thrust vectoring vanes (foot assembly) open up, and it's really only where the vanes meet the fuselage (what becomes the ankle armour) is where it's at its narrowest.

There's an excellent picture of that in the Variable Fighter Master File book in the VF-19, but it's not readily available on the net.

Making do... these two should describe what I'm referring to (the VF-19 cutaway does a better job of showing it):

http://www.macross2.net/m3/macross7/vf-19custom/vf-19custom-handandfoot.gif

 

 

 

[camk4evr]

The VF-1 (and, presuumably, the VF-25) have additional structures (vanes maybe) inthe 'foot' section that would, likely, further constrict the exhaust. The other two nacelle/leg designs (-11 and -19?) probably removed or reduced those interior structures to reduce complexity/ make maintence easier.

[aurance]

22 minutes ago, sketchley said:

We get what you're saying (refer to my comments on the F-22 above).

Those side on images are also a bit misleading.  Inside, the thrust vectoring vanes (foot assembly) open up, and it's really only where the vanes meet the fuselage (what becomes the ankle armour) is where it's at its narrowest.

Yes I know that too, but such a choke point does not seem to exist, or is much wider on the fighters on the right.

[aurance]

5 minutes ago, camk4evr said:

The VF-1 (and, presuumably, the VF-25) have additional structures (vanes maybe) inthe 'foot' section that would, likely, further constrict the exhaust. The other two nacelle/leg designs (-11 and -19?) probably removed or reduced those interior structures to reduce complexity/ make maintence easier.

This is the first reply that actually addressed my question. Thanks.😋

Edited February 11, 2022 by aurance

[sketchley]

12 minutes ago, camk4evr said:

The VF-1 (and, presuumably, the VF-25) have additional structures (vanes maybe) inthe 'foot' section that would, likely, further constrict the exhaust. The other two nacelle/leg designs (-11 and -19?) probably removed or reduced those interior structures to reduce complexity/ make maintence easier.

I was looking through the Variable Fighter Master File books, and if they are considered a trusted source (they self describe themselves as not being part of the official setting), then there is a different mechanism being used inside the nozzle of the VF-25 and VF-31.  Specifically: the thrust redirection plates (what "pinch" the flow to increase speed) are separate from the nozzle (foot) assembly itself.

So, going back to Aurance's post with the side-diagrams, the Valkyries should be lumped into 2 categories:

• non-"pinched" nozzles (VF-1)
• "pinched" nozzles (VF-4, 11, 19, 25, 31)

Of the latter, it appears there are 2 versions:

• foot assembly doubles as "pinching" mechanism (VF-11, 19 style)
• foot assembly and "pinching mechanism" are separate (VF-25, 31 style)

 

 

It probably doesn't help that Kawamori-san designed the VF-25 as an homage to the VF-1.  🤷‍♂️

Edited February 11, 2022 by sketchley

[aurance]

10 minutes ago, sketchley said:

I was looking through the Variable Fighter Master File books, and if they are considered a trusted source (they self describe themselves as not being part of the official setting), then there is a different mechanism being used inside the nozzle of the VF-25 and VF-31.  Specifically: the thrust redirection plates (what "pinch" the flow to increase speed) are separate from the nozzle (foot) assembly itself.

So, going back to Aurance's post with the side-diagrams, the Valkyries should be lumped into 2 categories:

• non-"pinched" nozzles (VF-1)
• "pinched" nozzles (VF-4, 11, 19, 25, 31)

Of the latter, it appears there are 2 versions:

• foot assembly doubles as "pinching" mechanism (VF-11, 19 style)
• foot assembly and "pinching mechanism" are separate (VF-25, 31 style)

 

 

It probably doesn't help that Kawamori-san designed the VF-25 as an homage to the VF-1.  🤷‍♂️

Awesome, thank you!

[Seto Kaiba]

34 minutes ago, camk4evr said:

The VF-1 (and, presuumably, the VF-25) have additional structures (vanes maybe) inthe 'foot' section that would, likely, further constrict the exhaust. The other two nacelle/leg designs (-11 and -19?) probably removed or reduced those interior structures to reduce complexity/ make maintence easier.

DINGDINGDING We have a winner, ladies and gents!

At least, for a number of these designs.

 

2 hours ago, aurance said:

Okay. I don’t think either of you are understanding what I’m saying. I’m already aware of the facts you two mentioned. And 'toys vary from real thing? Come on man, of course they do but that's not what I'm referring to. Let me try to add a drawing.

Seems like a deliberate change in design but my question was whether this was an in-world thing or just style. I guess we don't know. I should have clarified what I was pointing out.

So, as others have already noted, the point of a variable nozzle is to adjust the compression of the exhaust flow and thus the conversion of exhaust temperature into an increase in exhaust velocity.  When using an afterburner or afterburner-like function, you need to increase the mass flow through the nozzle to avoid excess pressure causing exhaust gases to flow upstream and cause unpleasant situations like a compressor stall or a fan surge.

There are basically two categories of engine nozzle design here, if you ignore certain extras like thrust reversers and so on:

• Engines with convergent nozzles
• Engines with convergent-divergent nozzles

You could also sum this up as an awful game of "Where's the de Laval nozzle?".

On the VF-0 and VF-1, the thrust-vectoring nozzle functions as a convergent nozzle in its normal position and opens wider at higher thrust levels.

The VF-1, however, has a convergent/divergent structure inside the engine body according to Master File and the older Sky Angels manual... though compared to later models of engine their exhaust temperatures and pressures were relatively low, though still VERY high compared to conventional jet engines.

 

On later models, the convergent-divergent (de Laval) nozzle moved downstream of the engine to take up a position between the engine and thrust vectoring nozzle, adopting a more complex design called a variable geometry convergent-divergent nozzle.  That vertical line marks the actual end of the engine housing, and you can see just aft of it there's that characteristic convergent-divergent bell shape - a de Laval nozzle - which is used to provide further exhaust velocity increase via flow compression.  This can be adjusted via those actuators that are also used to adjust the position of the thrust-vectoring paddles themselves.  (The part where it narrows is called the choke.)

 

The current type is just a slightly more complex version of that.

Instead of the leading edge of the thrust vectoring nozzle playing the role of the de Laval nozzle's choke, the thrust-vectoring nozzle and the choke are now independent of each other... the choke is farther up in the leg inside the ankle and the thrust-vectoring nozzle is now purely on the divergent end.

 

 

Essentially, on the VF-1 the de Laval nozzle was inside the engine.  After that, it moved to behind the engine with the choke being the leading edge of the thrust vectoring nozzles, until engine size increased enough that they could separate the choke from the thrust-vectoring nozzle.

I see @sketchley kind of beat me to the punch there, but I hope these (previously-posted) visual aids help make the point a bit clearer.

Edited February 11, 2022 by Seto Kaiba

[aurance]

That’s some great info, thanks! I wish I could read those Japanese labels.

Edited February 11, 2022 by aurance

[pengbuzz]

7 hours ago, Seto Kaiba said:

DINGDINGDING We have a winner, ladies and gents!

At least, for a number of these designs.

 

So, as others have already noted, the point of a variable nozzle is to adjust the compression of the exhaust flow and thus the conversion of exhaust temperature into an increase in exhaust velocity.  When using an afterburner or afterburner-like function, you need to increase the mass flow through the nozzle to avoid excess pressure causing exhaust gases to flow upstream and cause unpleasant situations like a compressor stall or a fan surge.

There are basically two categories of engine nozzle design here, if you ignore certain extras like thrust reversers and so on:

• Engines with convergent nozzles
• Engines with convergent-divergent nozzles

You could also sum this up as an awful game of "Where's the de Laval nozzle?".

On the VF-0 and VF-1, the thrust-vectoring nozzle functions as a convergent nozzle in its normal position and opens wider at higher thrust levels.

The VF-1, however, has a convergent/divergent structure inside the engine body according to Master File and the older Sky Angels manual... though compared to later models of engine their exhaust temperatures and pressures were relatively low, though still VERY high compared to conventional jet engines.

 

On later models, the convergent-divergent (de Laval) nozzle moved downstream of the engine to take up a position between the engine and thrust vectoring nozzle, adopting a more complex design called a variable geometry convergent-divergent nozzle.  That vertical line marks the actual end of the engine housing, and you can see just aft of it there's that characteristic convergent-divergent bell shape - a de Laval nozzle - which is used to provide further exhaust velocity increase via flow compression.  This can be adjusted via those actuators that are also used to adjust the position of the thrust-vectoring paddles themselves.  (The part where it narrows is called the choke.)

 

The current type is just a slightly more complex version of that.

Instead of the leading edge of the thrust vectoring nozzle playing the role of the de Laval nozzle's choke, the thrust-vectoring nozzle and the choke are now independent of each other... the choke is farther up in the leg inside the ankle and the thrust-vectoring nozzle is now purely on the divergent end.

 

 

Essentially, on the VF-1 the de Laval nozzle was inside the engine.  After that, it moved to behind the engine with the choke being the leading edge of the thrust vectoring nozzles, until engine size increased enough that they could separate the choke from the thrust-vectoring nozzle.

I see @sketchley kind of beat me to the punch there, but I hope these (previously-posted) visual aids help make the point a bit clearer.

Would it also be fair to say that UN Spacy also revised the designs for the engines based upon the theatre which the craft would operate in (atmosphere vs deep space)? I've read that some fighters like the VF-17 Nightmare were intended for space ops primarily (also, the VF-2 SS, albeit a different Macross reality); would that have any impact on on the design of the engine thrust nozzles?

[sketchley]

1 hour ago, pengbuzz said:

Would it also be fair to say that UN Spacy also revised the designs for the engines based upon the theatre which the craft would operate in (atmosphere vs deep space)? I've read that some fighters like the VF-17 Nightmare were intended for space ops primarily (also, the VF-2 SS, albeit a different Macross reality); would that have any impact on on the design of the engine thrust nozzles?

Yes it would be fair to say that.  Long story short: air intakes (the compressor stages) are less important in space, and the engines would take on more rocket-like aspects (larger fuel/gas inlets as they can't rely on an atmosphere for the gas that gets heated and shot out the rear end).  There'd likely be a greater emphasis on cooling, as well.

This is reflected in the engine output for the VF-19F and VF-19S.  Even though they are "all-regime" fighters, the VF-19F is more optimized for space.  And this is despite having essentially the exact same engines!

Quote

 

• Two 78,500 kg (maximum output in outer space) Shinsei Industry/P&W/Roice FF-2550J [72500 kg [x g] Shinnakasu Industry/P&W/Roice FF-2500F] thermonuclear turbine engines in VF-19F.
• Two 68,950 kg (maximum output in outer space) Shinsei Industry/P&W/Roice FF-2550X [78950 [68500] kg [x g] class Shinsei Industry/P&W/Roice FF-2550J] in VF-19S.

https://macross.anime.net/wiki/VF-19_Excalibur#Powerplant

 

 

 

I don't think it would have an impact on the choke (aka 'pinch') point just inside the nozzle.  On the other hand, the angle that the nozzle opens would have to change to be optimize for atmospheric or space operations.  However, as that's a standard feature in those nozzle (able to open wider or squeeze shut), there shouldn't be any drastic shape changes.

That said, this is where the fantasy of Valkyries slams head first into reality.  All the nozzles that we have seen are, frankly, extremely inefficient in space.  Truly space optimized Valkyries ought to have bell-shaped nozzles like the ones on the back of the Space Shuttle.

Long story short, have a look at the SpaceX Raptor engines on their Starship rocket.  These are the exact same engines.  The difference is one has a nozzle optimized for sea-level flight, the other nozzle is optimized for outer space.  Note that the bell curve angle (especially around the top) greatly differs.

 

 

Edited February 11, 2022 by sketchley

[Master Dex]

Man you guys talk about the stuff I actually got my degree in and researched when I was asleep or at work lol.

Luckily Sketchley and Seto are on point so far in terms of real engine stuff (how it relates to VF being their domain almost fully anyway) so I don't have too much to add but I'll jump in a bit.

Sketchley is right that the VF nozzles are sacrificing a lot of efficiency in space, though the ability to morph the nozzle geometry at all is kind of a holy grail that's just too complex and expensive to do with most rockets (and part of the reason aerospikes will probably always be best on paper only), so we can thank overtechnology for that. The fact that VFs in space use a wildly inefficient propulsion method already by spamming the fusion reactor exhaust as propellant (which is why they have short operation windows in space) kinda highlights that even if the nozzles could be ideal it would only be a minor improvement.

Thus the UN Spacy proves to be very pragmatic in their design. As a test engineer, I respect that. Eventually there is a point where good enough is the best you can hope for, even if on paper you can do better. If only I could make some professional colleagues I know understand that now... I digress though.

Tl;dr, VF engines can be optimized for air or space but the need for both creates operational inefficiencies that while regrettable, are still more than capable.

[pengbuzz]

  

8 minutes ago, Master Dex said:

Man you guys talk about the stuff I actually got my degree in and researched when I was asleep or at work lol.

Luckily Sketchley and Seto are on point so far in terms of real engine stuff (how it relates to VF being their domain almost fully anyway) so I don't have too much to add but I'll jump in a bit.

This is why I value all you folks' input here: everything I learn here goes into my projects in some form and helps with refinement of the ideas, concepts and finished parts that I come up with!

8 minutes ago, Master Dex said:

Sketchley is right that the VF nozzles are sacrificing a lot of efficiency in space, though the ability to morph the nozzle geometry at all is kind of a holy grail that's just too complex and expensive to do with most rockets (and part of the reason aerospikes will probably always be best on paper only), so we can thank overtechnology for that. The fact that VFs in space use a wildly inefficient propulsion method already by spamming the fusion reactor exhaust as propellant (which is why they have short operation windows in space) kinda highlights that even if the nozzles could be ideal it would only be a minor improvement.

Thus the UN Spacy proves to be very pragmatic in their design. As a test engineer, I respect that. Eventually there is a point where good enough is the best you can hope for, even if on paper you can do better. If only I could make some professional colleagues I know understand that now... I digress though.

Sometimes, you just gotta go with what works, even if it turns out to be "looping the belt around your shoulder and crotch" (from an old Gallagher skit) instead of around your waist.

"It would hurt, but it would work!!!"

8 minutes ago, Master Dex said:

Tl;dr, VF engines can be optimized for air or space but the need for both creates operational inefficiencies that while regrettable, are still more than capable.

In other words: they trade off efficiency for utility to some extent, right?

Edited February 11, 2022 by pengbuzz

[Knight26]

27 minutes ago, Master Dex said:

Man you guys talk about the stuff I actually got my degree in and researched when I was asleep or at work lol.

Luckily Sketchley and Seto are on point so far in terms of real engine stuff (how it relates to VF being their domain almost fully anyway) so I don't have too much to add but I'll jump in a bit.

Sketchley is right that the VF nozzles are sacrificing a lot of efficiency in space, though the ability to morph the nozzle geometry at all is kind of a holy grail that's just too complex and expensive to do with most rockets (and part of the reason aerospikes will probably always be best on paper only), so we can thank overtechnology for that. The fact that VFs in space use a wildly inefficient propulsion method already by spamming the fusion reactor exhaust as propellant (which is why they have short operation windows in space) kinda highlights that even if the nozzles could be ideal it would only be a minor improvement.

Thus the UN Spacy proves to be very pragmatic in their design. As a test engineer, I respect that. Eventually there is a point where good enough is the best you can hope for, even if on paper you can do better. If only I could make some professional colleagues I know understand that now... I digress though.

Tl;dr, VF engines can be optimized for air or space but the need for both creates operational inefficiencies that while regrettable, are still more than capable.

Well stated fellow Test Engineer.

[Master Dex]

44 minutes ago, pengbuzz said:

In other words: they trade off efficiency for utility to some extent, right?

In a strictly true sense, though that isn't the intent I figure. More just what they end up with than what they are striving to get.

There are likely ways and methods they could use to improve both but without a doubt they'd increase complexity and cost and you'd end up with the YF-29 problem; everything is great but we can't make more than a few.