RG 1/144 #28 Tallgeese EW

Designed by the five scientists, the Tallgeese was the first armed mobile suit, and is the common ancestor of both the Gundams (specifically their prototype, the XXXG-00W0 Wing Gundam Zero) and the mass-produced military mobile suits (most notably the OZ-06MS Leo and its variants). The Tallgeese was a well-rounded unit featuring both long-range and melee weapons, and also has heavy armor coupled with high power "Super Vernier" boosters.
Unfortunately, performing high-speed movement put an immense g-force strain on the pilot, with one theory saying the pilot would experience as much as 15 Gs.[1] To solve this problem and reduce production costs, the Tallgeese's design was simplified to create the Leo. After Zechs defected from OZ, Mike Howard, one of the original designers of the Tallgeese, equipped the suit with a large detachable booster unit that allows it to escape the Earth's atmosphere.