The RX-78-2 Gundam relied on the Gunperry for transportation at the early stages of the One Year War. During Operation Odessa, the Earth Federation replaced the Gunperry with the G-Amour, a support craft that was able to use the Core Block System.
The G-Armour was the combination of the RX-78-2 Gundam with the Core Block System modular units, known as the G-Parts. There were two sets of G-Parts: the A-Parts and the B-Parts. A-Parts consisted of a nose with a canopy cockpit, a set of caterpillar treads, and a pair of beam cannons. The B-Parts was a fuselage with four thrusters.
The Gundam’s torso was connected to the A-Parts at the top and B-Parts at the bottom to form the G-Armour. The support craft was able to quickly undock and split into the Gundam and the G-Fighter when there was a need for a change in battle tactics.
The G-Armour increased the battle stamina of the G-Fighter by tapping on the Gundam’s power generator. However, the increased mass reduced the manoeuvrability of the G-Armour, especially on the ground where it was outmatched by the fast mobile suits from the Principality of Zeon such as the MS-09 Dom.
The G-Armour was armed with beam cannons and missile launchers for ranged attacks. These were mounted on the A-Parts modular unit of the support craft.
There were a pair of beam cannons mounted on the top of A-Parts, just behind the canopy cockpit. The cannons could operate longer in the G-Armour configuration compared to the G-Fighter because of the additional generator from the Gundam torso.
The G-Armour had a missile launcher on each side of its nose. The missiles could be used against enemy mobile suits, ships or ground targets.
The G-Armour was mounted with two RX*M-Sh-008/S-01025 (Renpou eXperimental Medium Shield) shields, one on each side. Renpou means Federation in Japanese.
The shield was able to block most ballistic and explosive projectiles, providing greater protection for the A-Parts module in the G-Armour where the canopy cockpit was located.
Behind the scenes
Kunio Okawara was the original mechanical designer.
The G-Armour only appeared in the Mobile Suit Gundam anime series. It was removed in the compilation movies, because Yoshiyuki Tomino wanted to make the movies closer to his vision of for the series. So elements that were considered closer to the super robot genre were replaced with real robot elements.
However, Yoshiyuki Tomino felt that the G-Armour was considered closer to the super robot genre, instead of the real robot genre that he envisioned for the series. Thus, the G-Armour was removed in the compilation movies, and was replaced by the FF-X7Bst Core Booster.
The G-Armour appeared in Mobile Suit Gundam Extreme vs Maxi Boost as a playable unit. Although it was just another playable form of the Gundam, it was actually a reference to it being more of a super robot machine. It was able to combine with other segments to augment its abilities.