The Earth Federation Army will suffer a major defeat at the Lumum battle which is the first war of the one year war by the success of humanoid mobile weapon = mobil suit introduced by Zeon dictatorship army. The Earth Federation Army, which received this result heavily, thoroughly studied "MS - 06 Zaku II" which was the main force of the Army of Zeon Army, and made the Earth Federation Army Mobile Suit Development Plan "RX Plan" ("V strategy" It is also called).
We developed three kinds of mobile suits: "RX - 75 Guntank", "RX - 77 Gun Cannon" and "RX - 78 Gundam". Among them, "RX - 78 Gundam" is a high - performance aircraft that emphasizes approaching battle of mobile suits while taking advantage of the versatility of mobile suits that allow for the change of arms according to the battle situation, ignoring production cost Design and development were carried out as aircraft.
"RX-78 Gundam" has been changed in specifications at the development stage, the end of model number has been changed due to differences in specifications. The first specification at the time of rollout is the aircraft called "prototype Gundam" which has the model number of "RX - 78 - 1". In this specification, "RX - 78 Gundam" put emphasis on the close battle between the mobile suits, and thorough weight reduction was applied. Also, with regard to the main rifle beam rifle, we adopted a hand shot gun type that fixes the barrel on the forearm and shoots with one hand. And on the right waist side there was also a holster mount to fix the hand shotgun type beam rifle.
Three aircraft were produced as "RX-78-1 prototype Gundam" which is the initial specification, "Color 1" was decorated with black and red on the main body of silver in "RX-78 Gundam". After that, verify the data by simulation etc. of the completed aircraft. As a result of careful examination, specification changes such as shape change of the forearm and slit-shaped ankle guard, adoption of beam rifle capable of canceling the forearm fixed type, holding of both arms, and abolition of the waist holster are presented. The "RX-78-1 Gundam" developed at Jaburo is carried to the side 7 and collection of the production data is carried out, but the specification change presented at this time was given and both models have model number "RX- 78-2 ", and the painting was also reworked into tricolor color.
"RX - 78 - 1 prototype Gundam" was a vision specification that existed only for a very short time just after rollout. After that, Unit 1, which became the "RX-78-2" specification by the assault of the Zeon Duke Army on Side 7, wrecked. Unit 2 will be a legendary aircraft handed down after Amuro Ray boarding. Unit 3 was piled on the white base as a spare part of Unit 2 until it moved to Jaburo, after being rebuilt after arriving at Jaburo, after undergoing renovation to the third specification "RX - 78 - 3", the subsequent Gundam type It was used as a base for improvement and development of the mobile suits.