Zhang Tie stowed away the Chaos Armor at once, revealing his face beneath it. He glanced at Heller and the others, then burst into laughter...
"Edward, you've worked hard these past few days. The Flying Spears you made this time are indeed excellent. Your judgment was right: in kinetic attacks, round-headed Flying Spears truly encounter less resistance and travel faster than pointed ones..."
Edward was overwhelmed by the favor. The back he had just straightened bent toward Zhang Tie once more. "It is my honor to serve the Fortress Master!"
Over the past few days, Zhang Tie had worked with Edward in the Castle of Black Iron to trial-manufacture Flying Spears suited to his kinetic combat skill. After hundreds of experiments, Zhang Tie determined that the optimal weight for a Flying Spear he could use without affecting his throwing speed was 680 kilograms. Though he could still throw heavier Flying Spears, they would not travel as fast. After weighing everything together, he ultimately settled on that weight.
At first, Zhang Tie and Edward had disagreed over the Flying Spear's design. In Zhang Tie's view, since the Flying Spear would move at high speed, its tip naturally ought to be sharper, as that would reduce air resistance. Yet Edward insisted that the spearhead should be more rounded and did not need to be so sharp. Since they could not agree, Edward simply made Flying Spears in several different styles and let Zhang Tie test them himself. Having just done so, Zhang Tie discovered that, at the same weight, the round-headed Flying Spears made according to Edward's design really did fly faster and meet less resistance. The Flying Spears made according to his own design, though their tips were sharper, actually encountered greater resistance while flying through the air than Edward's round-headed