It followed the usual premise in the giant robot series being spewed out by the Japanese at that time. Aliens besieging earth and the humans using giant robots to fight them. The unique aspect with this series was that they only had about a minute to fight in the Mekanda Robot because the aliens had a satellite orbiting the earth that would release omega missiles at anything powered by nuclear energy.
Since that was a long, long (loooonng) time ago I doubt that I'd still really remember the entire concept of the show. Not to mention that television stations in my country had this bad habit of not finishing the series, leaving the kids with closure issues that they eventually have to deal with in the future.
Given that, guess I'd have to take wikipedia's explanation of the series as canon.
Three command jets combine to form one larger jet known as Mechander Max, which would then would dock at the back of Mechander Robo. Some of the trademark weapons include spiked shields, missile pod forearms, chest flame throwers and missiles shaped like sharks. Halfway through the series, Mechander Robo is severely damaged, but is rebuilt as four component ships combining to form the robot before docking with Mechander Max
One of the "cool" features of this robot was that it had bootlaces
Part of its arsenal was the Shark Missiles that shot out of its boots.
The back of the robot was the docking station of the Mekandar Max. 3 jets that would combine into one big jet.
Here's the Mekandar Max
Here's the Omega missile that would crash down towards the Mekanda robot. Yes, it was really designed to be ugly and to look like it was spewing nuclear radiation from its tip.
The other cool thing about this series was the cool opening song. It always made me want to sing it after hearing it... and maybe punch and kick something while I was at it.
Here's some sample video's I found of it at Youtube. Judging from the english dub, it must have come from the Philippines.