Questions about the GM Cannon

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False Prophet
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Questions about the GM Cannon

Post by False Prophet » Sun May 24, 2020 3:18 am

1 How much force would a 240 mm cannon exert on the GM Cannon when it fires? Would the machine's humanoid structure makes it unsuitable to bear that much force?

2. Why did they make the GM Cannon in the first place? The EFF had already mass-produced the Guncannon, as well as improved the concept with the Guncannon Heavy Custom and Guncannon II. None of these improvements went into the GM Cannon. And, I am under the impression that there wasn't a big demand for cannon-carrying MS during OYW.

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yazi88
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Re: Questions about the GM Cannon

Post by yazi88 » Sun May 24, 2020 4:28 am

The Project V Guncannon was a very LIMITED production unit as Federation barely rolled out a couple of units before the GM was officially rolled out. GM Cannon was a much cheaper unit with cheaper armor and performance which made it a lot easier for mass production. GM cannon also shared most of the same parts as the regular GM which helped reduced costs too.

As for the structure, compared to a regular GM, the GM Cannon had more armor on the waist and legs to give more balance and address the recoil problems from firing the cannon.

Gunncannon Heavy Custom was also made later during the war and was also a very limited production unit. I believe the Guncannon II was also made near the end of the war too.

The actual Guncannon Mass Production type itself didn't have that many units made either. It was also a late model unit in the OYW.

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MythSearcher
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Re: Questions about the GM Cannon

Post by MythSearcher » Mon May 25, 2020 5:30 am

The original (real-life) design of the Guncannon was supposed to have it fire the cannons while on all fours.(See MSG OP)
Later retcon made it into a heavily armoured MS which uses mass to overcome the recoil.
The GM Cannon, however, did not have all the heavy amour(It only increased the lower body armour) and thus did not have the same stability, reducing to just one cannon helps, but likely gave the unit a torque while firing.
Also, it is designed for support fire, so very likely most of its firing angles are closer to 30~40 degrees, which gives less tipping force to the humanoid shape.
If you want to know if the humanoid structure is suitable or not, try to stand straight and have a friend push you on the shoulder, you will find that if s/he push in the horizontal direction, it is harder for you to keep your pose than pushing at an angle towards the ground. Having one of your legs back can help you stand better when pushed.

The GM cannon's cannon had a few redesigns, the original MSV version(and the Zeta version) uses a 360mm rocket high muzzle velocity cannon, so it likely had low recoil. How it became the current 240mm I have no idea, but the Gun cannon current 240mm likely was shrunk to match the newer Guncannon cannon size(which was not specified in the old models[1/144 and 1/100] pre-dating the MSV GM cannon model) The current Guncannon 240mm is a low recoil cannon, so you have less problem.

Production number wise, the GM Cannon had either 34(old MSV manual) or 58(isn't a retcon because the MSV manual only stated the Oct, 0079 units) which isn't really much more than the Guncannon(4[Z-MSV] or 1+6[prototype+production, MSV 1/100]) RX-77D's production numbers doesn't come up in my mind for now, but shouldn't be many(You don't get a lot of EFF MS for any models in official publications, the most you get is the GM's 42+288 in the MG manual along with the Gundam Officials stating the number is too small but also rejecting the 5000 in a semi-official publication of Enterbrain saying that is too much)
As to why you still want the GM Cannon while the RX-77D seems to be enough, I see it as a shift into utilizing the GM production lines and as much GM parts as possible. RX-77D already use some of GM parts, the GM cannon is just using more of it to lower the cost. It uses 60% of GM parts, basically with some added armour and cannon.

It is a rather good unit as it as recorded as shooting down a Dabude class of Zeon, probably more favourable than having GMs holding bazookas as standins of a supporting MS since a fixed weapon is always more stable than a hand-held weapon, thus giving you a more accurate shot.
It you read the MG GM manual, you can see that the 5 GM team was planned to have 2 GM cannons, but since GM cannons are scarced(the production didn't make it during the war), most teams used Bazooka holding GMs or Balls for support fire instead.

Massignifico
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Re: Questions about the GM Cannon

Post by Massignifico » Mon May 25, 2020 6:41 am

Bear in mind that both GM Cannon Space Assault type and Guncannon Heavy type D are depicted with a 380mm Balzac Rocket Bazooka, so it seems that bazookas are still useful for support units.

And yes, fixed weapons can be more stable but bazookas are supposed to be recoilless and should be easier and faster to aim, not needing to move all the body to face the target.

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Re: Questions about the GM Cannon

Post by MythSearcher » Wed May 27, 2020 5:15 am

Massignifico wrote:
Mon May 25, 2020 6:41 am
Bear in mind that both GM Cannon Space Assault type and Guncannon Heavy type D are depicted with a 380mm Balzac Rocket Bazooka, so it seems that bazookas are still useful for support units.

And yes, fixed weapons can be more stable but bazookas are supposed to be recoilless and should be easier and faster to aim, not needing to move all the body to face the target.
The funny thing about this is, the 380mm bazooka is a calibre used by RX-78 as well, while the regular GM, even if it is assigned to be the support unit, uses the 320mm bazooka instead.

A bigger boom does give you a better support.

Also, I did notice the RGC-80S while being a MSV-R design, Kunio Okawara still gave it a 360mm fixed cannon, instead of the retconned 240mm cannon. I guess he does care about the numbers he put on his designs.

BTW, rocket bazooka? I do not know of any bazooka not using a rocket projectile. Ok, maybe Beam bazookas, but that is not common during OYW and the only instance is the MS-09R weapon.

Massignifico
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Re: Questions about the GM Cannon

Post by Massignifico » Thu May 28, 2020 12:31 pm

MythSearcher wrote:
Wed May 27, 2020 5:15 am
BTW, rocket bazooka? I do not know of any bazooka not using a rocket projectile.
It's just Gundam naming, strange for the sake of it. Or maybe to distract from the fact that this kind of bazooka is named after a french novelist... (not official but they didn't give any other explanation, did they?)

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MythSearcher
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Re: Questions about the GM Cannon

Post by MythSearcher » Thu May 28, 2020 9:42 pm

Massignifico wrote:
Thu May 28, 2020 12:31 pm
It's just Gundam naming, strange for the sake of it. Or maybe to distract from the fact that this kind of bazooka is named after a french novelist... (not official but they didn't give any other explanation, did they?)
Considering they have a (Mega) Bazooka Launcher,I always have this image of it launching volleys of bazookas instead of the beam they depicted in show, I guess you are right.

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Re: Questions about the GM Cannon

Post by JEFFPIATT » Sat Jun 27, 2020 11:10 pm

False Prophet wrote:
Sun May 24, 2020 3:18 am
1 How much force would a 240 mm cannon exert on the GM Cannon when it fires? Would the machine's humanoid structure makes it unsuitable to bear that much force?

2. Why did they make the GM Cannon in the first place? The EFF had already mass-produced the Guncannon, as well as improved the concept with the Guncannon Heavy Custom and Guncannon II. None of these improvements went into the GM Cannon. And, I am under the impression that there wasn't a big demand for cannon-carrying MS during OYW.
for 2 its cost rather than producing a MS with all new toolings the RGC series is a simple mod to a Existing RGM-79 unit aand a production line onlyn needs minor changes. it also streamlines logistics since the RGC-80 and the RGM-79 share parts and can use the same equipment,

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