Vintage MS: Playing With Specs

The future is now. This is the place for mecha and science.
toysdream
Posts: 3164
Joined: Mon Mar 06, 2006 12:24 pm
Location: San Francisco, CA
Contact:

Vintage MS: Playing With Specs

Two of my pet peeves when it comes to discussions of Gundam mecha are obsessing over specs, and futile attempts to reconcile conflicting info from incompatible sources. Of course, that makes me a big old hypocrite, because I ponder this stuff all the time. So let's see if I can turn my shame into a source of diversion for other mecha freaks!


General Principles
When it comes to One Year War mobile suits, the situation with their specs is really chaotic. Over the years, various sources -- Sunrise, Gundam Century, model kit manuals, the Entertainment Bible series, Hobby Japan's Gundam Mechanics books -- have proposed a huge range of different numbers for these vintage machines. (The recent MS Encyclopedia further muddies the waters by listing Sunrise-approved specs in its color pages and Gundam Mechanics specs in its black-and-white line art section.)

Even if we attempt to narrow things down by using the official anime specs as a guideline, it doesn't help much. In particular, the thruster layouts of the Zeon mobile suits are listed differently for pretty much every show. In Gundam 0080, the specs of the Rick Dom II and Gelgoog Jaeger include only their backpack and skirt thrusters. The specs for Gundam 0083 generally include only backpack and foot thrusters, and the total thrust of the Rick Dom II and Gelgoog Marine is about half of their Gundam 0080 analogues. The vintage machines in Gundam ZZ aren't even internally consistent; the Dowadge's thrust comes almost exclusively from its skirt and calf thrusters, while the ReGelgu's specs only list thrusters in its backpack and shoulder binders, suggesting that the thrusters in its skirt and legs -- which provided the entire propulsion of the original Gelgoog -- don't do anything at all!

As far as total thrust is concerned, I think I find the numbers from Gundam 0080 the most convincing. Gundam ZZ demonstrates pretty conclusively that vintage machines like the Dowadge and Gelgoog can fly for short periods under Earth's gravity, and in the animation, these older machines don't seem to handle any worse than the "modern" ones of the Zeta Gundam era. The notion that the Rick Dom II has 110,000 kg of thrust doesn't distress me; it's absolutely jam-packed with rocket engines, and I have no problem believing it has the same thrust-to-weight ratio as the Rick Dias.

Before we get into specific cases, I'll suggest one other rule of thumb. According to Entertainment Bible 1, the Guntank weighs 80 tons and has 88,000 kg of thrust, and the MSM-10 Zock weighs 229 tons and has 253,000 kg of thrust. Both of these machines have virtually no leg motion to speak of, they're both capable of launching vertically upwards using their thrusters alone, and they're both credited with 1.1 gees of thrust. This seems like a useful benchmark for things like the Dom series, but more on that later.


Case Study: MS-06R Series
As a warmup, let's look at the MS-06R High Mobility Type Zaku II. There are basically four sets of published figures to work with here:

* The old MSV kit manual says that the backpack thrusters of the standard MS-06R produce 218 tons of thrust apiece, and the six leg thrusters contribute 45 tons each. (This is based on the specs from Gundam Century, in which the regular Zaku's backpack thrusters are rated at about 105 tons each.)

* Entertainment Bible 1 says that the R-1A type has a total thrust of 49,800 kg. Its base and full weights are also listed as 61.8 tons and 76.8 tons respectively. The former figure was revised to 56.8 tons in recent editions of the MS Encyclopedia, which also claims that the R-2 type has a base weight of 58.2 tons.

* Hobby Japan's Gundam Mechanics series credited the MS-06R-1A with 52,000 kg of thrust. The R-2 type is listed as having 60,000 kg of thrust, and its base and full weights are given as 49.5 tons and 75.0 tons respectively.

* And finally, the original Master Grade MS-06R-1 and R-2 model kits included backpack stickers which read "hp 49,700kg" and "hp 56,200kg" respectively. It's not obvious whether we should read that as an electrical power output in horsepower or as a thruster output in kilograms, but the number for the R-1 is suspiciously close to the specs from Entertainment Bible 1, so I'll assume the latter.


MS-06R Thruster Specs
Looking at all these conflicting figures, the ones from Entertainment Bible 1, the MS Encyclopedia, and the MG kits appear to be the most "official". The thrust-to-weight ratio, however, seems to be really low for a rocket-boosted high-performance machine. So it stands to reason that this is probably a Gundam 0083-style figure that only includes the thrusters in the backpack and the soles of the feet, omitting the rocket engines in the legs.

So how powerful are those foot thrusters, anyway? We can find an answer by consulting Gundam 0083, which tells us that the MS-06F2 Zaku II has four 3,100 kg thrusters in its legs -- two in the calves, and two on the soles of its feet. If we subtract out the foot thrusters, then the contribution from the backpack would be: 49,800 - 6,200 = 43,600 kg. Which breaks down to two 21,800 kg thrusters. Which is exactly one-tenth of the figure in the MSV kit manual! What a handy coincidence!

In this case, can we just divide the rest of the MSV thruster outputs by ten? I don't see why not! After all, the specs for the MS-06G Zaku II in the current MSV-R series say that its very similar leg thrusters have an output of 3,500 kg each, so 4,500 kg for the leg thrusters of the R-1A type seems perfectly reasonable. This gives us the following...

Thruster output: 21,800 kg x 2 (backpack), 3,100 kg x 2 (feet), 4,500 kg x 6 (legs)

By another uncanny coincidence, this comes to a total of 76,800 kg. So if the full weight spec from Entertainment Bible 1 is still valid, then the R-1A type has a thrust-to-weight ratio of exactly 1.0.

What about the R-2 type? Well, if we take the output listing on the backpack of the MG kit and subtract the standard foot thrusters, we get: 56,200 - 6,200 = 50,000 kg. Which means that each backpack thruster is rated at 25,000 kg, a nice round number. As for its leg thrusters, these are a new design that was apparently repurposed from the abandoned MS-11 project, and so we can only guess. However, they should be at least as powerful as those of the R-1A type, and so this machine would have well over 80,000 kg of thrust in total.


MS-06R Weight Specs
I'm not sure how much I want to get into weight specs here, since these are really all over the map. But in Zeta Gundam and Gundam ZZ, we're given detailed weight specs complete with a "mass ratio" figure, which we can use to figure out how many tons of propellant each machine carries. The difference between base weight and the "unfueled" weight would be the optional carried weapons, and in the Zeta and ZZ specs this almost always turns out to be a nice round number (which suggests that these weapon payloads, and thus the full weight spec, are actually just estimates).

The Hizack, which is based on the MS-06R series, has a base weight of 38.7 tons, a full weight of 59.6 tons, and a mass ratio of 1.33. That's a difference of 20.9 tons between the base and full weight, and using the mass ratio spec, we can break it down into 6.0 tons of weapons and 14.9 tons of propellant.

If the MS-06R-1A has a base weight of 56.8 tons and a full weight of 76.8 tons -- which seems to be the current official line -- then that's a weight difference of 20.0 tons. Hypothetically, we could break this down into 5.0 tons of weapons (one notch below the Hizack) and 15.0 tons of propellant (virtually identical to the Hizack).

The R-2 type, meanwhile, is said to have 18% more propellant than the R-1A version. Based on the above figures, this would come to roughly 17.7 tons. Add that to the base weight of 58.2 tons, and the same 5.0 tons of weapons cited above, and we get a full weight of 80.9 tons. We could round this up to 81.0 tons if we aren't too picky about hitting that 18% figure, and it would go up or down slightly if we adjust the weapons-versus-propellant breakdown for the R-1A type. But it's also possible that the R-2 type has a higher weapons payload -- after all, it uses the same bazooka as Dom-series machines like the Dowadge, which carries 6.0 tons of weapons -- so the figure should perhaps be in the ballpack of 82 tons. This still gives the R-2 a slightly better thrust-to-weight ratio than its predecessor, although we know from the MSV background info that its performance isn't quite as high as that of the Rick Dom.


Speaking of which: Next time, the Dom series!

-- Mark
User avatar
Geoxile
Posts: 974
Joined: Thu Dec 11, 2008 11:48 pm

Re: Vintage MS: Playing With Specs

Well

I guess those Zeeks better cash out for the track model for better performance.
User avatar
MrMarch
Posts: 1093
Joined: Thu Nov 30, 2006 2:58 am
Location: Toronto, Ontario, Canada

Re: Vintage MS: Playing With Specs

A very interesting read and I really liked how you were able to come up with a highly plausible rating for thrusters based on a process of elimination and collation of published facts. I often have to do the same when building my own website. Your analysis made for a good read. I've also scratched my head at the incorrect thruster counts for several Gundam mobile suits. Some counts seem to forget the feet, while others will miscount the legs or include thrusters where they shouldn't be. Great to see a fan do some research on it. Well done!

Speaking of which an interesting situation occurred when I was recently building the Gundam profiles for the "More Mecha" section of my site and enjoying the first episode of Gundam Unicorn. I realized that they've published enough thrust/weight information for the Gundam Unicorn mobile suits to calculate ratios, something that hasn't been done in years. So as a fan exercise, I went through many Gundam series and calculated a list of T-W ratios, both empty and gross (so they could be compared to those mobile suits that only featured an "empty" weight). I found some official figures were in error and noted them. I figure if my findings can help you, I'll post them here for your information.

Mobile Suit Gundam (UC 0079)

RX-78-2 Gundam (empty) = 1.28
RX-78-2 Gundam (max gross weight) = 0.93

RGM-79 GM (empty) = 1.35
RGM-79 GM (max gross weight) = 0.94

MS-06F Zaku II (empty) = 0.74
MS-06F Zaku II (max gross weight) = 0.59

Mobile Suit Gundam: The 08th MS Team (UC 0079)

RX-79[G] Gundam Ground Type (empty) = 0.98
RX-79[G] Gundam Ground Type (max gross weight) = 0.71

Mobile Suit Gundam 0080: War in the Pocket (UC 0079-0080)

RX- 78NT-1 G-4 Gundam Alex (empty) = 3.3
RX- 78NT-1 G-4 Gundam Alex (max gross weight) = 1.82
RX- 78NT-1FA G-4 Gundam Alex (full armor empty) = 3.48
RX- 78NT-1FA G-4 Gundam Alex (full armor max gross weight) = *1.93
(*officially listed as 1.83, but the math result is 1.93)

MS-06FZ Zaku II Kai (empty) = 1.41
MS-06FZ Zaku II Kai (max gross weight) = 1.07

MS-18E Kämpfer (empty) = 3.66
MS-18E Kämpfer (max gross weight) = 2.03

Mobile Suit Gundam 0083: Stardust Memory (UC 0083)

RX-78GP01 Gundam "Zephyranthes" (empty) = 2.72
RX-78GP01 Gundam "Zephyranthes" (max gross weight) = 1.66

RX-78GP01-Fb Gundam Full Vernian "Zephyranthes" (empty) = 5.42
RX-78GP01-Fb Gundam Full Vernian "Zephyranthes" (max gross weight) = 3.16

RX-78GP02A Gundam "Physalis" (empty) = 2.85
RX-78GP02A Gundam "Physalis" (max gross weight) = 1.87

RX-78GP03S Gundam "Dendrobium Stamen" (empty) = 4.52
RX-78GP03S Gundam "Dendrobium Stamen" (max gross weight) = 2.69

RX-78GP03 Gundam "Dendrobium Orchis" (empty) = 10.00
RX-78GP03 Gundam "Dendrobium Orchis" (max gross weight) = 5.00

Mobile Suit Gundam Zeta (UC 0087)

MSZ-006 Zeta Gundam (empty) = 3.92
MSZ-006 Zeta Gundam (max gross weight) = 1.81

RX-178 Gundam Mark II (empty) = 2.43
RX-178 Gundam Mark II (max gross weight) = 1.50

RX-178+FXA-05D Super Gundam (max gross weight) = 1.77

RMS-106 Hizack (empty) = 1.67
RMS-106 Hizack (max gross weight) = 1.09

Mobile Suit Gundam Double Zeta (UC 0088)

MSZ-010 Gundam Double Zeta (MS mode empty) = 3.09
MSZ-010 Gundam Double Zeta (MS mode max gross weight) = 1.48
MSZ-010 Gundam Double Zeta (G-Fortress mode) = 2.46 G
MSZ-010 Gundam Double Zeta (Core Top with Neo Core Fighter) = 1.73 G
MSZ-010 Gundam Double Zeta (Core Base with Neo Core Fighter) = 2.76 G

MSA-003 Nemo (empty) = 1.77
MSA-003 Nemo (max gross weight) = 1.15

AMX-006 Gaza-D (empty) = 3.42
AMX-006 Gaza-D (max gross weight) = 1.44

Mobile Suit Gundam: Chars Counterattack (UC 0093)

RGM-89 Jegan (empty) = 2.29
RGM-89 Jegan (max gross weight) = 1.03

RX-93 n Gundam (empty) = 3.51
RX-93 n Gundam (max gross weight) = 1.55

AMS-119 Geara Doga (empty) = 2.35
AMS-119 Geara Doga (max gross weight) = 1.06

MSN-04 Sazabi (empty) = 4.36
MSN-04 Sazabi (max gross weight) = 1.87

Mobile Suit Gundam Unicorn (UC 0096)

RGZ-95 ReZEL = 3.16

AMS-129 Geara Zulu (base weight) = 2.85
AMS-129 Geara Zulu (full weight) = 1.13

RX-0 Unicorn Gundam = 6.02

Mobile Suit Gundam F91 (UC 0123)

Gundam F91 (empty) = 12.28
Gundam F91 (max gross weight) = 4.44

XM-01 Den'an Zon (empty) = 10.99
XM-01 Den'an Zon (max gross weight) = *4.99
(*another error, officially listed as 3.99 but the math result is 4.99)

Mobile Suit Victory Gundam (UC 0153)

LM312V04 Victory Gundam (empty) = 10.49
LM312V04 Victory Gundam (max gross weight) = 4.50

LM314V21 Victory 2 Gundam (empty) = 5.90
LM314V21 Victory 2 Gundam (max gross weight) = 4.26
maximum thruster acceleration: mobile suit mode 20 G (note the obvious inconsistency)

G-Saviour (UC 0223)

G-Saviour Origin (dry) = 14.57
G-Saviour Origin (basic) = 10.35
Thrust to Weight Ratio (max load) = 1.85

G-Saviour Space Mode (dry) = 31.90
G-Saviour Space Mode (basic) = 7.18
G-Saviour Space Mode (max load) = 5.93

New Mobile Report Gundam Wing: Endless Waltz (AC 195)

XXXG-00W0 Wing Gundam Zero (empty) = 11.02
XXXG-01D2 Gundam Deathscythe Hell (empty) = 10.17
toysdream
Posts: 3164
Joined: Mon Mar 06, 2006 12:24 pm
Location: San Francisco, CA
Contact:

Re: Vintage MS: Playing With Specs

Thanks, MrMarch! Personally, I don't see to much value in figuring thrust-to-weight ratios using the empty weight; this includes neither carried weapons nor propellant, so in this situation a mobile suit could neither fly nor fight. But as for the questionable cases you flagged...

Full Armor Alex: There's a typo in the MAHQ profile. Its full weight should be 95.0 tons.

Den'an Zon: Another typo in the MAHQ profile. That should read "2 x 17,310 kg", for a total thruster output of 69,500 kg.

Victory 2 Gundam: I think I've written about this a bunch of times already (most recently in a fairly stupid thread here). Based on the original Japanese sources, the 20G figure appears to be a theoretical limit of the Minovsky Drive system itself, and may not reflect its performance once installed in the V2 Gundam. On the other hand, the thrusters listed in the official specs are sub thrusters and these thrust specs specifically don't include the Minovsky Drive. As a result, the effective thrust and performance of the V2 is unknown and unknowable.

Moving over to Gundam Unicorn: We don't have full weights for the Unicorn and the ReZEL, so there's no point in figuring their thrust-to-weight ratios. On the other hand, we're starting to see more and more specs dribble out from this series, so we can actually fill in a few other gaps...

RGM-96X Jesta: Full weight 57.2 tons, thruster output 89,030 kg, 1.56 gees.

NZ-666 Kshatriya: Full weight 74.02 tons, thruster output 197,800 kg, 2.67 gees.

YAMS-132 Rozen Zulu: Full weight 72.6 tons, thruster output 257,200 kg, 3.54 gees.

AMA-X7 Shamblo: Full weight 283.9 tons, thruster output 226,480 kg, 0.80 gees (plus Minovsky craft system).

-- Mark
jtrainor
Posts: 67
Joined: Sat Mar 18, 2006 7:09 pm

Re: Vintage MS: Playing With Specs

I'd like to suggest that most MS will generally accelerate at between 1.0 and 2.5 Gs to make things easier on the pilot. F-91 era MS may be able to accelerate at 4+ Gs, but I can't imagine that's very comfortable, even with a special suit.
User avatar
domtropen
Posts: 502
Joined: Fri Dec 15, 2006 6:07 am

Re: Vintage MS: Playing With Specs

the V2's 20G thrust is an urban legend now :twisted:

Anyway at least in MS-06F/J and RX-79[G] what appears in the anime is not possible by t/w ratio anyway. There are many instances where MS-06F/J just rockets itself straight up in the air, and in 08th MS Team episode 4 IIRC Sanders's Gundam basically scoots and flys up to Apsalas with rocket thrusters.

It would be interesting to see how MS-06S compare to MS-06R with all the data avaliable too.
toysdream
Posts: 3164
Joined: Mon Mar 06, 2006 12:24 pm
Location: San Francisco, CA
Contact:

Re: Vintage MS: Playing With Specs

domtropen wrote:Anyway at least in MS-06F/J and RX-79[G] what appears in the anime is not possible by t/w ratio anyway. There are many instances where MS-06F/J just rockets itself straight up in the air, and in 08th MS Team episode 4 IIRC Sanders's Gundam basically scoots and flys up to Apsalas with rocket thrusters.
Very true! At that point, we either have to assume that they're kicking off really hard against the ground, or that there's some kind of "overboost" setting on their thrusters. At least in the case of the Guntank and Zock, we can rule out the first of those possibilities. :-)
It would be interesting to see how MS-06S compare to MS-06R with all the data avaliable too.
Ever since the MSV era, it's been consistently claimed that the thrusters of the MS-06S (or at least its backpack thrusters) are 30% more powerful than those of a standard Zaku. Since the current sources all agree that the standard version has either 43,000 or 43,300 kg of thrust, Char's Zaku should have about 56,000 kg... plus whatever's contributed by the little calf thrusters they like to add to the model kits.

How does that compare against the available published specs? Hobby Japan's Gundam Mechanics books credit Char's Zaku with 51,600 kg of thrust (exactly 20% more than a standard Zaku). The HG-UC and Perfect Grade model kits say it has 48,500 kg. Those both seem too low, but if we take the latter figure as reflecting only the backpack thrusters, then it actually would be about 30% higher. (If the standard Zaku has the same foot thrusters as the F2 type, then the backpack itself would provide about 37,000 kg of thrust, and the S type backpack provides 30% more.) At that point, we could even make the tongue-in-cheek assumption that figure from Gundam Mechanics is a "typo" - they added in one of the foot thrusters but forgot the other, which would bring the total to 54,700 kg excluding the calf thrusters.

Incidentally, I think the oddball figure of 43,300 kg for the standard Zaku is probably back-figured from Gundam Century and the MSV series. In these sources, it's claimed that the backpack thrusters of the MS-06S are rated at 130 tons each, versus 105 tons for the standard Zaku. If you take the 130-ton figure and divide by three (as per Char's famous "three times faster") then you get 43.3 tons.

-- Mark
User avatar
MrMarch
Posts: 1093
Joined: Thu Nov 30, 2006 2:58 am
Location: Toronto, Ontario, Canada

Re: Vintage MS: Playing With Specs

toysdream wrote:Thanks, MrMarch! Personally, I don't see to much value in figuring thrust-to-weight ratios using the empty weight; this includes neither carried weapons nor propellant, so in this situation a mobile suit could neither fly nor fight. But as for the questionable cases you flagged...

Full Armor Alex: There's a typo in the MAHQ profile. Its full weight should be 95.0 tons.

Den'an Zon: Another typo in the MAHQ profile. That should read "2 x 17,310 kg", for a total thruster output of 69,500 kg.

Victory 2 Gundam: I think I've written about this a bunch of times already (most recently in a fairly stupid thread here). Based on the original Japanese sources, the 20G figure appears to be a theoretical limit of the Minovsky Drive system itself, and may not reflect its performance once installed in the V2 Gundam. On the other hand, the thrusters listed in the official specs are sub thrusters and these thrust specs specifically don't include the Minovsky Drive. As a result, the effective thrust and performance of the V2 is unknown and unknowable.

Moving over to Gundam Unicorn: We don't have full weights for the Unicorn and the ReZEL, so there's no point in figuring their thrust-to-weight ratios. On the other hand, we're starting to see more and more specs dribble out from this series, so we can actually fill in a few other gaps...

RGM-96X Jesta: Full weight 57.2 tons, thruster output 89,030 kg, 1.56 gees.

NZ-666 Kshatriya: Full weight 74.02 tons, thruster output 197,800 kg, 2.67 gees.

YAMS-132 Rozen Zulu: Full weight 72.6 tons, thruster output 257,200 kg, 3.54 gees.

AMA-X7 Shamblo: Full weight 283.9 tons, thruster output 226,480 kg, 0.80 gees (plus Minovsky craft system).

-- Mark
Okay, since those are typos on the MAHQ I'll make sure to note them and correct my own calculations. These appear to be holdovers from the Mecha Domain, since my copy of Rukes old website shows the same typo figures.

I calculated empty thrust-to-weight ratios mostly so all the other mobile suits could be compared to Gundam Wing Endless Waltz (which feature only "empty" trivia figures). Also, the empty figures have value if one wants to compare the relative impact of loads upon mobile suits and how loads have increased/decreased between various Gundam eras. Empty T-W ratios also permit speculative comparison using gross loads of comparable mobile suits. One could theoretically use the empty-to-gross weight ratio of the original RX-78-2 Gundam as an arbitrary baseline for determining the gross weight of a Gundam Wing suit. While it's true any such calculation is simply speculation without credence, as I've stated its a fan exercise that can provide an approximate range of likely results.

At any rate, I hope the information is somewhat useful. I figured if any fan was interested, it'd be you :)
User avatar
Brave Fencer Kirby
Posts: 1308
Joined: Tue Jan 30, 2007 3:14 pm

Re: Vintage MS: Playing With Specs

jtrainor wrote:I'd like to suggest that most MS will generally accelerate at between 1.0 and 2.5 Gs to make things easier on the pilot. F-91 era MS may be able to accelerate at 4+ Gs, but I can't imagine that's very comfortable, even with a special suit.
I feel compelled to note that modern-day fighter pilots wearing g-suits are expected to be able to withstand around 9 gs without losing consciousness, the space shuttle pulls about a max of 3 gs during takeoff, and humans can survive over 100 gs in instantaneous events like car crashes (though not nearly that much in extended timeframes, obviously).

Assuming that MS pilots are trained to withstand high-g maneuvers (why wouldn't they be?) and that pilot suits act something like a g-suit (they're already providing mechanical counterpressure in their role as space suits, so it's not too much of a stretch), I wouldn't be surprised to hear that the mechanical limits of MS are the bottleneck of performance, rather than human tolerance.
Fighting evil so you don't have to!
toysdream
Posts: 3164
Joined: Mon Mar 06, 2006 12:24 pm
Location: San Francisco, CA
Contact:

Re: Vintage MS: Playing With Specs

Brave Fencer Kirby wrote:I feel compelled to note that modern-day fighter pilots wearing g-suits are expected to be able to withstand around 9 gs without losing consciousness, the space shuttle pulls about a max of 3 gs during takeoff, and humans can survive over 100 gs in instantaneous events like car crashes (though not nearly that much in extended timeframes, obviously).
True, although in the case of fighter jets, only a fraction of that comes from the engines. Most of the extreme g-forces a pilot is subjected to come from flying maneuvers, turns, dives, etc, rather than the sustained forward thrust of the jet engines.

Likewise, a mobile suit pilot would be subjected to additional g-forces as the mobile suit turns, maneuvers, fires its maneuvering verniers, kicks other giant robots in the face, etc. If your main propulsion engines were already subjecting you to as much sustained acceleration as a jet pilot experiences while making a brief daredevil maneuver, then actually maneuvering your machine would probably kill you. :-)

-- Mark
User avatar
Areku
Posts: 1216
Joined: Mon Feb 11, 2008 12:00 am

Re: Vintage MS: Playing With Specs

toysdream wrote:True, although in the case of fighter jets, only a fraction of that comes from the engines. Most of the extreme g-forces a pilot is subjected to come from flying maneuvers, turns, dives, etc, rather than the sustained forward thrust of the jet engines.

Likewise, a mobile suit pilot would be subjected to additional g-forces as the mobile suit turns, maneuvers, fires its maneuvering verniers, kicks other giant robots in the face, etc. If your main propulsion engines were already subjecting you to as much sustained acceleration as a jet pilot experiences while making a brief daredevil maneuver, then actually maneuvering your machine would probably kill you. :-)
That depends. Most cockpits appear to be relatively close to the suit's center of mass, so rotational movements wouldn't be that intense on the pilot.

Also, in the seated position, the human body can sustain greater gee forces when accelerating forward and backward than it can up or down. It has to do with blood flow to the brain (though one mustn't forget the eyes). MS pilots don't normally appear to be accelerating straight up or down (unlike fighter pilots whenever they're experiencing high gees), so they could probably stand higher gees than fighter pilots.

Finally, aside from rotational maneuvers, an MS pilot won't experience gees higher than their suit's current thrust-weight ratio (unless they collide, like kicking other giant robots in the face). Simply changing the direction of thrust (and that's the only effective way to change course outside of a gravity well) won't change the magnitude of acceleration, which caps out at the T-W ratio.
toysdream
Posts: 3164
Joined: Mon Mar 06, 2006 12:24 pm
Location: San Francisco, CA
Contact:

Re: Vintage MS: Playing With Specs

Moving onward, let's take a look at the Dom series...


All Those Thrusters
Aside from its bulky appearance, probably the most obvious trait of the MS-09 Dom and its variations is the huge number of thrusters crammed into its body. The original TV series indicated that the Dom and Rick Dom had thrusters in their backs, skirts, and legs. Later episodes showed visible thruster openings on the soles of the Rick Dom's feet, and the new animation produced for the Gundam III movie depicted the Rick Dom with three thruster nozzles in its skirt and three in each calf. That's a grand total of thirteen thrusters, which are faithfully reproduced in the toys and model kits. However, the animation never shows them all being used at the same time.


Dom Propulsion
The original Dom technically has two kinds of propulsion system. Its legs contain nuclear thermal jet engines which are used for hovering movement, while its back and skirt house conventional rocket engines for forward propulsion. We're told that it can cruise along using the jet engines alone, reserving the fuel-guzzling rockets for emergency speed boosts, and this is exactly what we see in the original series and Gundam ZZ.

One ambiguous point, though, is the nature of those calf thrusters. It's universally agreed that the devices on the soles of the feet are jet engines, but the published sources disagree as to whether the calf thrusters are rockets or additional jet engines, whose output is directed downward by the leg armor to enhance the hovering effect. The waters are further muddied by the Prototype Dom, which has a rocket engine on the back of each calf and hovering vents on the sides. But there are a couple of occasions in the original series where we clearly see the calf thrusters firing, and they emit a bright yellow flare like the rocket engines in the skirt and back. The hovering jets, wherever they're located, have no visible flare and simply kick up a big cloud of smoke or dust around the mobile suit's feet.

This suggests to me that only the nozzles in the soles of the feet are actually hovering jets, and that the calf thrusters are rocket engines for extra forward propulsion, as described in the MG kit manual. Even if the Prototype Dom was set up differently, this seems to be how the production version works, and the Dom Tropen which appears in Gundam 0083 doesn't seem to have any calf thrusters at all.

In practice, the ground versions of the Dom rely mainly on their hovering systems, using their other thrusters only for jumping and emergency maneuvers. Even then, they mostly just use the back rockets, and there are only a couple of occasions where we see them using the skirt and calf thrusters. Most notably, in episode 24 of the original series, the Black Tri-Stars briefly fire their back, skirt, and calf thrusters in order to jump from one hill to another. (This is one of the only times we ever see all these thrusters used simultaneously.)


Rick Dom Propulsion
In the Rick Dom, the jet engines in the soles of the feet are replaced by rocket engines. The animation, however, is less consistent about the usage of all these rockets. The original TV series seems a bit uncertain as to whether the leg thrusters are located in the feet, calves, or both, and the Gundam III movie, having finally figured out what the skirt and calf thrusters look like, uses them as much as possible (especially in the battle with Conscon's fleet).

There's still a general trend, though, and by the time of Gundam 0083 it's been pretty much established that the Rick Dom relies mainly on its back and foot thrusters. The skirt and calf thrusters, no matter how lovingly detailed, are hardly ever used; their main function seems to be providing a brief burst of acceleration to charge into battle, make a quick escape, or thrust directly upward to dodge an enemy attack. For the most part, then, the assumption made by the Gundam 0083 specs - that only the back and foot thrusters are used on a regular basis - is borne out by the animation.

Not to get ahead of ourselves, but this seems to be true of the Gelgoog series as well. Its calf thrusters are hardly ever seen or used (only in Gundam III, as far as I can tell), and although the standard Gelgoog relies on its skirt thrusters as its main propulsion system, the backpack-equipped versions use them only in emergencies. All of this gives the impression that these thrusters are powerful but inefficient (due to limited fuel supply, awkward placement, or both).


Specs At Last
What does this mean in terms of specs? Let's start by considering the Rick Dom II. According to Gundam 0080, it has a total thrust of 110,000 kg (21,000 kg for each of its five skirt thrusters, and two 2,500 kg thrusters which are presumably in the backpack). According to Gundam 0083, it only has half as much thrust - 21,000 kg x 2 in the backpack, and 7,000 kg x 2 in the feet, for a grand total of 56,000 kg.

Based on the animation, the 0083 specs seem pretty reasonable, but they don't account for the seldom-used skirt and calf thrusters. In the spirit of reconciling incompatible sources, let's assume that these extra thrusters account for the remaining 54,000 kg difference. So these thrusters -- in the rare event that they're all used simultaneously -- enable the Rick Dom II to momentarily double its thrust.

This doesn't tell us how to divvy them up, though. In the extreme case, we could credit the entire amount to the skirt thrusters, and some of the specs from Zeta Gundam and Gundam ZZ give us a precedent for mobile suits packing 50-60,000 kg of thrust into their skirts alone. But it seems only fair to show some love to those poor neglected calf thrusters; after all, the official specs for Gundam ZZ's Dowadge indicate that they're almost as powerful as the skirt thrusters, and we previously factored them into the specs of the MS-06R.

What about the regular Rick Dom? The official specs say it only has 53,000 kg of thrust, which presumably accounts for the back and foot thrusters as with the Rick Dom II. Although it would also get a considerable boost from its skirt and calf thrusters, this would probably be somewhat smaller than that of the Rick Dom II, since it only has three skirt thrusters. The precise figure depends on how you divvy up the Rick Dom II's "booster" thrust, and whether you assume both machines have the same size skirt thrusters. This is basically an exercise in pure speculation, and it would be mean of me to deprive you of it. :-)


Back to the Dom
Another Dom variant from Gundam 0083 is the Dom Tropen, which has 58,600 kg of thrust -- 22,00 kg x 2 in the backpack, 7,300 kg x 2 in its feet. That's slightly more than the original Dom, which is credited with 58,200 kg of thrust. Perhaps we could account for this difference by assuming that the original Dom uses the same 21,800 kg backpack thrusters as the MS-06R-1A, another machine with Zimmad-manufactured engines which rolled out at roughly the same time.

Based on the animation, it seems like the Dom relies mainly on its back and foot thrusters, with the skirt and calf thrusters used almost exclusively for jumping. When these are factored in, its total thrust would be considerably higher. Even if we ignore the thruster breakdown in the Dowadge's official specs (which credit its thrust almost entirely to the skirt and calf thrusters), its total thrust of 104,300 kg seems perfectly consistent with the figures we were just throwing around for the Rick Dom and Rick Dom II.

What of the original Dom? Once again, it only has three skirt thrusters to the Dowadge's five, and the design of its back thrusters is clearly pretty different. Presumably its total thrust would be a little lower, but we can't really guess how much. I'll throw in another data point, though: According to Gundam Century, each of its jet engines has an output of 95,400 kg. That's obviously too high for a single thruster, but it actually works pretty well as a figure for the Dom's total thrust. In this case, the skirt and calf thrusters are giving us a boost of 37,200 kg. According to the MG kit manuals, the skirt thrusters of the original Dom are somewhat smaller than those of the Rick Dom, so this helps us set a lower limit for the Rick Dom's booster thrust as well.


Whew! There's a bit more I could talk about with these machines, especially when it comes to weight and propellant specs, but I think that's enough for the moment.

-- Mark
User avatar
Wingnut
Posts: 6026
Joined: Sun Mar 05, 2006 7:44 pm
Location: Detroit, MI
Contact:

Re: Vintage MS: Playing With Specs

toysdream wrote:This suggests to me that only the nozzles in the soles of the feet are actually hovering jets, and that the calf thrusters are rocket engines for extra forward propulsion, as described in the MG kit manual. Even if the Prototype Dom was set up differently, this seems to be how the production version works, and the Dom Tropen which appears in Gundam 0083 doesn't seem to have any calf thrusters at all.
This could be that the Dom Tropen/Funf seems to have a bigger footprint and calf section in general than the regular Dom and any other Dom built before it. Thus it could perhaps accommodate a bigger jet engine that would put out enough thrust to where it simply doesn't need the extra rocket engines in the legs to give it its get up and go power. Although the Tropen has a couple of what look like extra engines on the outer ankle which the Funf lacks. Given that these seem to have no exit port and seem to feed back into the leg itself, they could simply be supplemental air intakes for the jet engine.
The Gundam wiki

"Reality makes a crappy special effects crew." - Adam Savage

R.I.P., SDGO.
toysdream
Posts: 3164
Joined: Mon Mar 06, 2006 12:24 pm
Location: San Francisco, CA
Contact:

Re: Vintage MS: Playing With Specs

Wingnut wrote:This could be that the Dom Tropen/Funf seems to have a bigger footprint and calf section in general than the regular Dom and any other Dom built before it. Thus it could perhaps accommodate a bigger jet engine that would put out enough thrust to where it simply doesn't need the extra rocket engines in the legs to give it its get up and go power. Although the Tropen has a couple of what look like extra engines on the outer ankle which the Funf lacks. Given that these seem to have no exit port and seem to feed back into the leg itself, they could simply be supplemental air intakes for the jet engine.
Exactly - these are air intakes with big honking dust filters. The Dom Tropen also has extra gear on its feet with fancy hovercraft skirts. Without all this extra equipment, its feet are actually no bigger than those of the standard Dom, and any thrusters in the calf section would have ample clearance.

Given how infrequently the Dom uses those calf thrusters, it's possible that they didn't even bother to remove them from the Dom Tropen, and that there are a full set of useless thrusters hidden behind the extra foot gear. But I don't think the foot thruster itself is any bigger than that of a regular Dom - the specs indicate it has about the same output as the foot thrusters of the Rick Dom II and Gelgoog Marine, and if the standard Dom's foot thruster were any weaker, it would probably be pretty useless for hovering.

-- Mark
User avatar
domtropen
Posts: 502
Joined: Fri Dec 15, 2006 6:07 am

Re: Vintage MS: Playing With Specs

toysdream wrote:The original Dom technically has two kinds of propulsion system. Its legs contain nuclear thermal jet engines which are used for hovering movement, while its back and skirt house conventional rocket engines for forward propulsion. We're told that it can cruise along using the jet engines alone, reserving the fuel-guzzling rockets for emergency speed boosts, and this is exactly what we see in the original series and Gundam ZZ.
Assuming that the jet engines in the foot are the main ones for cruising, aren't these jet engines need to be much more powerful than indicated in the spec? In order to lift itself off the ground Dom's foot engines should provide close to or more powerful thrust than Dom's own full weight [even counting presumed hovering effect]?
toysdream
Posts: 3164
Joined: Mon Mar 06, 2006 12:24 pm
Location: San Francisco, CA
Contact:

Re: Vintage MS: Playing With Specs

domtropen wrote:Assuming that the jet engines in the foot are the main ones for cruising, aren't these jet engines need to be much more powerful than indicated in the spec? In order to lift itself off the ground Dom's foot engines should provide close to or more powerful thrust than Dom's own full weight [even counting presumed hovering effect]?
I think we've discussed this before, but it would depend on whether the hovering system works by providing enough upward thrust to balance out the mobile suit's own weight (which is the assumption reflected in Gundam Century's specs), or by creating a cushion of high-pressure air underneath the mobile suit's foot like a conventional hovercraft. In the latter case, the hover system basically eliminates all friction with the ground, allowing the mobile suit to slide around like an air-hockey puck.

Based on the animation, as well as the current specs, it seems like the Dom is supposed to use the second of these methods (hovercraft style). In this case, you'd expect it to have a hovercraft-style "skirt" around the foot jet to keep the air cushion in place, which is presumably why mecha designer Hajime Katoki added one to the Dom Tropen. (The earliest real-world hovercraft didn't have these, but it quickly turned out to be a major improvement.)

-- Mark
Zeonista
Posts: 1178
Joined: Sun Nov 08, 2009 5:47 pm
Location: in ur colony, steelin ur gundam

Re: Vintage MS: Playing With Specs

Wow, you guys are great, much headaches saved on estimating MS performance for the ongoing RPG. B) Some definite consideration will have to be given for speed and maneuverability, both in design and player tactics. (Somehow I don't think the group will mind being able to go faster. :) )
"I am fire. I am death. I am Hashmal."

"Discontent is the first step in the progress for a man or a nation." - Oscar Wilde
toysdream
Posts: 3164
Joined: Mon Mar 06, 2006 12:24 pm
Location: San Francisco, CA
Contact:

Re: Vintage MS: Playing With Specs

A couple of followup points on the Dom, before we move on to other machines...


Skirts Reconsidered
I hate to admit it, but I've been wracked with tiny pangs of guilt over my assumption that the 54,000 kg of "booster" thrust I attributed to the Rick Dom II comes from the combined skirt and calf thrusters. The more I think about it, the more reasonable it seems to credit this entirely to the skirt thrusters.

For one thing, after reviewing the thruster specs from Zeta Gundam, Gundam ZZ, and Char's Counterattack, it seems as if most mobile suits that have thruster nozzles in their skirts get 10-15 tons of thrust out of each one, and thus 40-60 tons of thrust out of an entire set of skirt thrusters. Examples include the Zeta Gundam itself (12,200 kg x 5), the Gabthley (12,600 kg x 6), the Galbaldy Beta (15,800 kg x 4), the Dreissen (9,800 kg x 4), the R Jarja (11,200 kg x 5), and the Re-GZ (11,000 kg x 4). Ditto for the leg thrusters; although the square vents on the legs of the Alex and Zeta Gundam are rated at just seven or eight tons each, cone-shaped thruster nozzles are typically rated at nine or ten. There's precious little consistency in mobile suit specs, but where these types of thrusters are concerned, there do seem to be a few rules of thumb.

Meanwhile, although we haven't gotten to the Gelgoog series yet, we'll eventually have to consider this machine as well. The official specs for the standard Gelgoog say it has 61,500 kg of thrust, most of which would have to come from its three skirt thrusters. (We've repeatedly seen this machine fly in atmosphere, and the Zaku FZ kit manual says its performance is comparable to that of a Gelgoog, so it must have some extra "booster" thrust that's not included in this baseline figure.) If all the thrusters in the skirt and calves of the Rick Dom II amount to a measly 54,000 kg, then they'd have to be far punier than those of the Gelgoog.

And finally, we have the comparison of the Rick Dom II and the Gelgoog Jaeger. The official specs for Gundam 0080 say that both machines have five 21,000 kg thrusters in their skirts, with the remainder of their thrust coming from the backpack. Even if we're redistributing this output, the fact remains that the Jaeger would still have 105,000 kg worth of thrust in its main body, and the thruster layout of the Rick Dom II is so nearly identical that it's hard to believe it would only have 68,000 kg (that's 110,000 kg, minus the two 21,000 kg backpack thrusters listed in the 0083 specs).


Back to the Dowadge
In this case, maybe we should take the specs of Gundam ZZ's Dowadge more seriously. Officially, this model has five 9,300 kg thrusters in its skirt, six 8,200 kg thrusters in its calves, and two 4,300 kg thrusters in its back. This doesn't account for the jet engines in the soles of the feet, and the backpack thrusters are implausibly weak, but the skirt and calf thrusters are well within the normal range. In this case, the skirt thrusters would be produce a total of 46,500 kg, which is pretty close to the "booster" figures I was throwing about in my earlier post. In particular, the 37,200 kg of extra thrust I wanted to give the original Dom is equal to exactly four Dowadge skirt thrusters - probably a meaningless coincidence, but it suggests that the Dowadge replaced the original thrusters with smaller devices that had exactly 75% of their output.

What about the legs? Well, we could just take the official specs at face value. But if we wanted to take greater liberties, we could assume that the two 4,300 kg thrusters are actually in the feet, and then "borrow" one ton of thrust from each calf thruster to bring these up to the 7,300 kg output of the Dom Tropen's foot jets. At this point, we'd have the terrestrial branch of the Dom family spec'd out as follows:

MS-09: 21,800 kg x 2 (back), 7,300 kg x 2 (foot jets), 12,400 kg x 3 (skirt), 7,200 kg x 6 (legs)
MS-09F: 22,000 kg x 2 (back), 7,300 kg x 2 (foot jets), UNKNOWN (skirt)
MS-09G: UNKNOWN (back), 7,300 kg x 2 (foot jets), 9,300 kg x 5 (skirt), 7,200 kg x 6 (legs)

This gives the Dowadge 104,300 kg of thrust (as per the official specs), plus an unknown amount from the back thrusters. And the original Dom, in the almost unprecedented event that it fires every one of its thrusters at the same time, would momentarily be able to muster 138,600 kg of thrust - more than enough to send it rocketing from one hilltop to another, as we see it do in the original series. More precisely, that hilltop jump is performed using only the rocket engines in the back, skirt, and calves, and not the hovering jets in the feet. I'm pleased to see that, based on the specs above, these rocket engines would produce a total of 124,000 kg of thrust - the kind of nice round number one very seldom encounters with this kind of number-crunching game!

That might seem like an awful lot of thrust - more than twice the official specs, and enough to briefly produce 1.5 gees of acceleration (I'm assuming that the foot jets aren't used while airborne). On the other hand, as I noted above, the Dom and Gelgoog series virtually never use all their thrusters at the same time, so this peak performance is mainly theoretical and doesn't really apply to the situations we see in the animation. In that case, what does this tell us about the Rick Dom?


And Rick Doms Again
For starters, let's go back to the Rick Dom II. I'd previously suggested that the "booster" thrusters in the skirt and calves accounted for the 54,000 kg difference between the Gundam 0080 and Gundam 0083 specs. If this comes entirely from the skirt thrusters, then they'd be rated at 10,800 kg apiece. I note, though, that the Gundam 0080 specs include two 2,500 kg thrusters (that's why it has five more tons of thrust in its body than the Gelgoog Jaeger). I think these were originally supposed to be the backpack thrusters, but if we can attribute them to something else - perhaps the "ventilated fins" on the tail of its skirt armor? - then it'll make it a lot easier for us to use the same thruster specs for the Gelgoog Jaeger later on. (Trust me on this one.) That leaves 49,000 kg in the skirt proper, or 9,800 kg per thruster, just like those of the Dreissen.

If we apply the same principle here that we did to the Dowadge and Dom - that the five smaller thrusters are exactly 75% as powerful as the three larger ones - then the skirt thrusters of the standard Rick Dom would be rated at either 13,000 kg or 14,400 kg apiece. In both cases, the output is a rather flimsy extrapolation, and I'd consider it merely a ballpark estimate. But they should be at least as powerful as those of the original Dom, and their combined output should be less than that of the Rick Dom II's skirt thrusters.

The calf thrusters are presumably similar to those of the original Dom, and the Rick Dom may very well use the same type. The Rick Dom II, on the other hand, is a product of the United Maintenance Plan which standardized the components of all Zeon's mass production mobile suits. In this case, I'm inclined to give it the same 7,000 kg thrusters that Gundam 0083 says are installed in its feet, and in the legs and feet of the Gelgoog Marine. (The "standardized parts" excuse would also explain why the Zaku II F2 has 3,100 kg thrusters in its legs, and the Zaku II FZ has 3,000 kg ones.) We could also posit that the Rick Dom and Rick Dom II have the same type of calf thrusters, but I think the United Maintenance Plan excuse is pretty compelling, so I'll go with the following two scenarios...

Scenario one: Simple division.

MS-09R: 53,000 kg (back and feet), 14,400 kg x 3 (skirt), 7,200 kg x 6 (legs)
MS-09R-2: 21,000 kg x 2 (back), 7,000 kg x 2 (feet), 10,800 kg x 5 (skirt), 7,000 kg x 6 (legs)

Scenario two: Factoring in mysterious tail thrusters.

MS-09R: 53,000 kg (back and feet), 13,000 kg x 3 (skirt), 7,200 kg x 6 (legs)
MS-09R-2: 21,000 kg x 2 (back), 7,000 kg x 2 (feet), 2,500 kg x 2 (tail), 9,800 kg x 5 (skirt), 7,000 kg x 6 (legs)

The Rick Dom would have a peak thrust of 139,400 kg in the first scenario, and 135,200 kg in the second one. Either way, the Rick Dom II has 152,000 kg, which is even more huge than Gundam 0080 already indicated. But once again, these figures are mostly theoretical, so I don't find them too hard to accept.

Of these two scenarios, I lean towards the second one. Excluding the backpack and tail thrusters, the Rick Dom II would have exactly 105,000 kg of thrust, which means we can use the very same numbers for the Gelgoog Jaeger.


Rats, I was going to talk about weight specs, but this ended up running way long again! Next time, I guess.

-- Mark
Zeonista
Posts: 1178
Joined: Sun Nov 08, 2009 5:47 pm
Location: in ur colony, steelin ur gundam

Re: Vintage MS: Playing With Specs

The Dom section alone has made my week. B)
toysdream wrote:
Brave Fencer Kirby wrote:I feel compelled to note that modern-day fighter pilots wearing g-suits are expected to be able to withstand around 9 gs without losing consciousness, the space shuttle pulls about a max of 3 gs during takeoff, and humans can survive over 100 gs in instantaneous events like car crashes (though not nearly that much in extended timeframes, obviously).
True, although in the case of fighter jets, only a fraction of that comes from the engines. Most of the extreme g-forces a pilot is subjected to come from flying maneuvers, turns, dives, etc, rather than the sustained forward thrust of the jet engines.

Likewise, a mobile suit pilot would be subjected to additional g-forces as the mobile suit turns, maneuvers, fires its maneuvering verniers, kicks other giant robots in the face, etc. If your main propulsion engines were already subjecting you to as much sustained acceleration as a jet pilot experiences while making a brief daredevil maneuver, then actually maneuvering your machine would probably kill you. :-)

-- Mark
Wasn't the linear seat cockpit supposed to help deal with the additional g-forces? It's been demonstrated that 0080-0083 MS show a lot of acceleration and maneuvering verniers, and thus a greater tendency to challenge (and pummel) the pilot. Given the situation in0087, wouldn't it seem that MS designers came up with the linear seat to help the pilots deal with thrust-happy MS?
"I am fire. I am death. I am Hashmal."

"Discontent is the first step in the progress for a man or a nation." - Oscar Wilde
toysdream
Posts: 3164
Joined: Mon Mar 06, 2006 12:24 pm
Location: San Francisco, CA
Contact:

Re: Vintage MS: Playing With Specs

Zeonista wrote:The Dom section alone has made my week. B)
I'm glad! It feels like it took me a week to write it. :-)
Wasn't the linear seat cockpit supposed to help deal with the additional g-forces?
Yep; one of the key examples that's been cited in the Japanese sources is the Galbaldy Beta, whose performance was more than most pilots could handle before the linear seat was introduced. But that's not a question of straight-line acceleration so much as sheer maneuverability.
It's been demonstrated that 0080-0083 MS show a lot of acceleration and maneuvering verniers, and thus a greater tendency to challenge (and pummel) the pilot. Given the situation in0087, wouldn't it seem that MS designers came up with the linear seat to help the pilots deal with thrust-happy MS?
A good question. One of things I've really noticed in watching all this Dom and Gelgoog animation is that they keep switching between different sets of thrusters to maneuver in different directions - a single machine might start out cruising with the backpack, then lurch upwards with the skirt thrusters, kick out with the foot thrusters, and dodge to the side with the shoulder verniers. (You won't really see all of those in a single sequence, but you do see combinations of them, especially in Gundam 0083.) Aside from being complicated to control, this has got to be tough on the pilot, much more so than if they had one big thruster pointing in the same direction all the time.

This, of course, is part of the reason why we have all these transformable machines popping up in Zeta Gundam. A machine like the Gabthley has just as many "thruster clusters" as these One Year War models, but in mobile armor form they're all pointing in the same direction and can be fired simultaneously. But I think it's also a pretty good reason to attach the pilot to a magnetic shock-absorber, too. :-)

-- Mark
Post Reply