Mecha featured in the 80s anime TV show Kikou Souseiki Mospeada.
It is a three-form transformable fighter called the Armo-Fighter AFC-01 Legioss, which is used by the humans to fight the Inbit aliens that have invaded Earth.
It has 3 modes: Armo-Fighter (Jet/Starfighter), Armo-Soldier (Giant Robot) and Armo-Diver (Gerwalk). The Legioss can be connected in tandem with the Tread heavy mecha.
This mecha was designed by Aramaki Shinji in the early 80s.
The Legioss is somewhat similar in design to the VF-1 Valkyrie variable fighter from Choujikuu Yousai Macross (1982), which aired a year before Mospeada (1983).