RCX-76 Guncannon: Why did it suck so bad?

[doghunter1]

On the idea of the RCX-76 being a "Guntank with legs," based on the the fact the hands of all RCX-76s aren't exactly like ours, whereas Zeon's mobile suits and the Project V equipment do have human-esque hands, I'd say "Guntank with legs" was the idea the Anaheim bigwigs went with. Tem Ray suggested they ought to perfectly replicate all ten fingers of a human being, but said Anaheim bigwigs opposed the idea. Come Mare Smythii, and the rest is history.

[Gelgoog Jager]

I ran into an interesting concept about the Gundam Mk III while checking Deacon's site:

...the Gundam Mk-III was perfected and was said to have been the latest evolution of general purpose mobile suits due to the concept which focused on returning to the starting point of mobile suits: organic movement, similar to that of the human body.

http://www.zeonic-republic.net/?page_id=4048

This got me thinking if this could be the key difference between the RCX-76 and Zeon's MS: the approach to achieve organic human-like mobility. The Zakus and Bugu seem to be running and jumping around swiftly all over the place while the Guncannons are depicted as being more clumsy and stiff. Also, I suppose that in order to properly support their artillery cannons they were given a more rigid structure, as well as different weight distribution to better deal with the recoil. For instance, the GM Cannon has bigger and heavier legs that can be assumed have that same purpose.

[JEFFPIATT]

I ran into an interesting concept about the Gundam Mk III while checking Deacon's site:

...the Gundam Mk-III was perfected and was said to have been the latest evolution of general purpose mobile suits due to the concept which focused on returning to the starting point of mobile suits: organic movement, similar to that of the human body.

http://www.zeonic-republic.net/?page_id=4048

This got me thinking if this could be the key difference between the RCX-76 and Zeon's MS: the approach to achieve organic human-like mobility. The Zakus and Bugu seem to be running and jumping around swiftly all over the place while the Guncannons are depicted as being more clumsy and stiff. Also, I suppose that in order to properly support their artillery cannons they were given a more rigid structure, as well as different weight distribution to better deal with the recoil. For instance, the GM Cannon has bigger and heavier legs that can be assumed have that same purpose.

BSWD ON QHt i have seen on the RGC-80 GM Cannon's developemnt the first prototype units were stock RGM-79 GM bodies with Guncannon backpacks and heads attacjed and due to the GM using the Gundam's lighter close combat frame the units could not keep balance while firing with the recoil knocking them over. the final unit used only one cannon and the heavy leg armor was added as a counter balance.

[Gelgoog Jager]

One quick correction: RGC-80 units are not converted from RGM-79, according to Mark they were built as that from scratch:

Nah, the GM Cannon was never a "field mod of a stock GM." All the Japanese sources make it very clear that it was planned and developed as a mass-produced version of the Guncannon, and just ended up using all those GM parts for the sake of economy. At any rate, they were all produced like that, and none of them were converted from existing GMs.

viewtopic.php?f=17&t=12502#p272580

So, basically they are mass produced Guncannons made with GM parts in order to reduce costs.

From the examples we know, recoil do is a big problem for land-based MS. It's not surprising that first attempts for both sides were tank type units: the Guntank series and the Hildolfr.

The concept of the MS-06K started as an anti-air unit (supposedly with the gatling gun backpack from MSV-R), which likely worked worked with a standard Zaku frame, but upon trying to produce a MS like the Guncannon, it should have become evident that the Zaku frame was not ideal for that job. The unit seen on 08th MS team should be a clear example of how bad the recoil was for a MS-06K, ultimately preferring to have the unit as fixed artillery.

In Zeon's case, the Dom frame seemed to be the ideal solution: it is heavy and has large legs that allow it to withstand the recoil, and it hovering system allows it to quickly relocate after firing. It's not surpassing that two variants for different roles were made: the long-ranged MS-09K1 and the middle-range MS-09K2. Later on, the concept would evolve into the YMS-16M, a machine which has a torso resembling the Hildolfr and using a 680mm cannon (over twice as large as the YMS-05T 300mm), which likely was the artillery weapon mounted on a MS at the time.

Late in the conflict, both sides embraced the idea of replacing ballistic cannons with beam cannons, which also happened to solve the recoil problem. The order in which this happened is not quite clear, but I'm of the opinion that the MS-14C was probably the first unit that employed the concept, but not for recoil problems, but rather because Zeon had yet to produce E-Cap based beam weapons. The YMS-14 was rolled out on October, but Zeon's E-Cap based weapons wouldn't be ready u too a couple of weeks before the end of the war, and as such the MS-14C's beam cannon backpack, which included its own generator for providing direct feed to its weapon, essentially served as a step gap measure for the Gelgoog series.

On Earth, California Base continued their their own MS development projects, which late in the war produced the MS-05L and the MS-14GD. The MS-06K, which externally seems to be a hybrid design that incorporates features from other units such as the YMS-09 and MS-14C, has some obscure background mentions of actually having a beam cannon, which given the afore-mentioned recoil issues, do would be an option for a Zaku frame unlike a large ballistic canon, like this of the MS-09K series. The existence of the MS-05L also proves that California Base was working on generator-driven beam weapons for their units with insufficient generator output.

As for the EF, after they managed to recapture California Base, where they developed RX-77-4 unit, the EF's own attempt at a support artillery MS that replaced ballistic cannons with a recoiled beam weapon. This do hints that the EF researchers likely found data or even captured units with such features, which they decided to imitate. The EF would continue to play with the concept in he following years, resulting inunits such as RGC-83.

[JEFFPIATT]

Ieonically the Test type GM cannon does look like they took parts from both a RX-77-2 and a RGM-79 and combinded the parts to do the first units but the GM frame being much lighter led to issues with keeping the ballence like the zaku cannon units had. the final model basically moved the armor around and removed one cannon to solve the issue and manage to get 60% parts commonality with the RGM-79 GM. the cannon on the final model seems to have the same ammo cartridge as the BLASH HB-L-03/N-STD Hyper Bazooka while the RGTM-80-1 just has a boxier version of the guncannon backpack.. the only real compedeter for the GM cannon line was the RX-77D Guncannon MP- type a scaled down version of the RX-77-2 but lacked Parts compatibility.
http://gundam.wikia.com/wiki/RGC-80-1_G ... _Test_Type
http://gundam.wikia.com/wiki/RGC-80_GM_Cannon
http://gundam.wikia.com/wiki/RX-77D_Gun ... ction_Type

[Gelgoog Jager]

the only real compedeter for the GM cannon line was the RX-77D Guncannon MP- type a scaled down version of the RX-77-2 but lacked Parts compatibility.

I wouldn't call the RX-77D a scaled down version of the Guncannon, but rather a naturally more modern approach, with higher emphasis on mobility and cost:

Much like the GM Sniper II, it was built with Titanium Ceramic Composite armor, and seemed capable of using the RGM-79G's beam gun. It was also as light as a RGC-80, which used a lighter GM frame as a base (51.0 MT VS 49.9 MT), despite being bulkier and better armored. More importantly, it was significantly lighter than the original Guncannon, which had a base weight of 70.0 MT. While the obvious tradeoff is the loss of the the durable (but expensive) luna titanium alloy, TCC is supposedly better than the vanilla titanium armor of standard MG, and supposedly also provides slightly better protection against beam weapons. Cost-wise, TCC is certainly more cost-effective than luna titanium alloy.

It's worth noticing that more advanced variants of the Guncannon, such as the RX-77-3, RX-77-3D and RX-77-4, all have become lighter and added more thrusters, confirming the trend of seeking to make these artillery support units more mobile.

The RX-77D do seems to have been mass produced to some degree, given that the White Dingo Team got ahold of some units and Lydo Wolf, the EF's Black Dancing Death, also piloted one.

I think the real reason it wasn't further adopted is that the EF preferred to have all it's mass production machines based on the GM series, with the RGC-83 looking more like a Full Armor option of the RGM-79N rather than a variant of it.