Chapter 102 — The Magical Energy Engine

"'Useful motive force' is called 'work,'" Gao Yang seized the chance to instill the terms he was familiar with, and at the same time he had already worked out how to solve the machine "fighting itself." For Earth's four-stroke engines or other classic engines, the piston's return stroke required exhaust to relieve the cylinder's pressure; for this machine, he needed to stop the repulsion array the instant the piston returned. "A rune trigger—we can use a rune trigger to control the repulsion array. When the piston moves away from the base of the power mechanism, the rune trigger connects; when the piston is carried back by the flywheel and approaches the base, the rune trigger breaks the circuit..."

More magical symbols sprang into Hetty's mind. "But how do we control it? The flywheel spins fast, and the piston moves fast too. A magical formula that reacts so swiftly—switching the rune trigger's position in an instant—that would require high-grade runes..."

Before she had even finished thinking it through, Rebecca said offhandedly: "Just tie the rune trigger to the piston. When the piston comes near the base, the base connects, then the piston gets pushed away, and as soon as it comes near it gets pushed away, as soon as it comes near it gets pushed away... Wow, bouncing all over the place."

So just what kind of image had surfaced in this girl's head to make the words "bouncing all over the place" come out of her mouth?

Hetty and Gao Cen stared at Rebecca—the former astonished at how ingenious this solution was, the latter marveling that the silly doe really was a natural-born engineering genius. How did she manage to switch seamlessly between magical knowledge and mechanical knowledge, to leap out of her current line of thought in an instant and produce results in a new one? Did her brain not need to cool down? Or did these two bodies of knowledge somehow run in parallel within her mind—whichever one produced a solution, that was the one she used?

Rebecca, under their stares, shrank back: "Did I say something wrong?"

"No, no, no, this is a very good approach," Hetty said, waving her hand quickly. "And I've thought of more: why carve only one repulsion array? The piston moves back and forth, so we can perfectly well carve a repulsion array at the other end of the power mechanism as well. That way the piston gets two power strokes in a single reciprocation..."

Gao Yang, too, studied the sketch on the table earnestly. Musing on the placement of the rune trigger, he suddenly had another idea: "Also, fixing the rune trigger to the piston isn't the best solution either—it means it only connects for an instant in each cycle. We can mount it on the flywheel's axle instead, and have both rune arrays at either end of the piston controlled by this one trigger, using a 'toggle' device to switch which magical circuit the trigger sits in. That is, while the flywheel turns through its first half-rotation, the rune stays inside the first array; while it turns through the other half, the rune connects to the other array. That way, the whole time the piston is being pushed away from the repulsion array, the first repulsion array is doing its work, until the piston reaches its farthest point—then the first array shuts off, the second switches on, and the piston reverses. What do you think?"

Rebecca gaped, looked at Hetty, then at Gao Yang, and suddenly her mouth drooped in dejection: "I really am the dumbest one after all..."

"You're not dumb in the least!" Gao Yang was caught between laughter and tears by this girl's habitual self-deprecation. "The whole repulsion-array idea came from you. Your aunt and I have only been hammering and tinkering on top of that."

Rebecca's mouth stayed drooped: "But the idea for this machine still came from you, Ancestor Yan."

"But without your inspiration, this machine of mine would probably have stayed a drawing forever," Gao Rong spoke up. "Don't you think you're impressive?"

"Really?"

Gao Yang and Hetty nodded, smiling together: "Really, really."

"Oh!"

"By the way, Ancestor, have you named this device yet?" Something suddenly occurred to Hetty. "This entirely new thing... you have the right to give it a new name."

"A name..." Gao Yang fell to thinking, and a name rose to the surface of his mind. "Then let's call it the magic energy engine."

Hetty listened to this unfamiliar word, pieced together with strange grammar, and a smile slowly spread across her face: "Ancestor, that really is a good name."

Rebecca nodded eagerly too: "Yes, yes! I don't understand what it means, but it sounds so cool!"

Looking at the two "granddaughters" lost in excited delight, Gao Yang instead lowered his head to his sketch, and a new thought surfaced in his mind:

Could this structure be improved any further?

Or rather... since the repulsion array and the rune trigger already laid the groundwork, why not go a step further and build something more advanced, a machine with an entirely different architecture?

For instance, like an electric motor driven by electromagnetic force, one could do away with the pistons, connecting rods, and crankshaft, and instead etch the repulsion array at a certain angle onto a ring-shaped housing to drive the magic-conducting rotor inside?