I would translate “人有多大胆，地有多大产” into “The world of ingenuity is as big/vast/great as man’s daring”, or perhaps to match the pun he’s evoking with 胆 and the large diameter bombs, “The world of ingenuity is as big/vast/great as man’s bombast”.
The images below are an example of his enigmatic style. Obviously the they don't match any known airframe. The accompanying poetic verse expresses something along the lines of (in my awkwardly poetic translation): "however bigly people dare to dare, the 'earth' can spring a match for that dare." Of course, part of his Weibo username means "grassroots", and grass and their roots are from the ground. So 'earth' could simply mean his imagination, or maybe not. I'm getting carried away.
I'd keep a watch on his account but not take everything he posts too seriously.