Aitor Alert! Manuballista found!

[D B Campbell]

"Why did they ever block up what little view they had on the wood-framers with decorative metal sheeting?"

It wasn't really a question of blocking it up. The narrow aperture was a consequence of the arrow-shooter's euthytone design. Setting the springs farther apart (to create a better view) would presumably have placed intolerable strain on the wooden framework (Heron's peritrêta). Remember, this design was the result of years of trial and error, and was judged to be the optimum by engineers like Heron.

Why did Heron specify that the width should be more that 2X arms length? Wouldn't one length have been enough?

I'm not sure what you're referring to here. Width of what?

More importantly, why does everyone focus exclusively on the flat trajectory direct fire mode? Just because a weapon does one thing very well doesn't mean it can't do others.

That's true. But I think I've explained why, in my opinion, a high trajectory is less desirable for an ancient gunner.

Even if the air resistance could stop the bolt in mid air, it would fall at terminal velocity with all it's mass. I guarantee you wouldn't want to be under it when it did.

But remember -- we're talking about an arrow, not a shell. By its very nature, a catapult targets individuals. Unless you actually hit an individual (and I would argue that indirect, high trajectory shooting reduces your chances of doing this), the catapult loses its effectiveness as a weapon of terror. You may as well use archers.