I have searched over and over trying to find this, so now finally posting the question to see if anyone else has a clue about this. My details are vague, but here goes. I remember watching a cartoon in the 80s about big robots. I do not believe it was Voltron and I know it is not Transformers or GoBots. I believe that people were in the robots. It could have been Mazinger, Robotech, Gundam, maybe?
I am thinking about one episode in particular. The good robot/robots/mechas had to protect a city that was under attack by TWO villain monsters. One was a typical walking robot and it had wings, sort of spherical, which I believe were red, and it closed itself up in those wings, using them as a shield which the good robot could not penetrate. My naming of them as wings could be wrong, I just know it would close up like a clamshell to protect itself from blasts.
The other monster robot was (again, I think...I was very young) a white robot, a scorpion I think. I remember the good guys thinking the city was lost, as they could not stop the winged/shielded robot that was attacking the city. Then they realized/figured out that the real thing they needed to destroy was the white scorpion robot. That is all I can remember.
I do remember there being a very anime art to it, with dark cannon blasts, damage, etc. Think Voltron.
Hoping anyone out there has an idea, I realize it is not much to go on.