Chapter 74 - Turned Over

Once Taquoho descended low enough to actually translate my words, I’m sure it wasn’t lost on the Ifrit that, if they wanted similar treatment, they would have to learn to communicate with words, befriend goblins, and earn their favor. After all, every hobgoblin and noblin understood the fundamentals of flight thanks to the quasi-gestalt nature of the Goblin Tech Tree.

With one swoop, I’d turned them from obstacles to goals in their own right and given more Ifrit a reason to leave their xenophobia at the door. Sustained flight is a powerful motivator. Sure, an Ifrit could copy the design, and probably even improve on it. But I’m betting it would lack that Goblin Tech Tree special sauce that greased the applied sciences on Rava. Gliders and coaxial Ifrit vessels were, for the moment, a monopoly of Tribe Apollo. And soon, we’d have another.

I checked on the engine seals for our first rotary engine and found that they had cured enough for a test, and that the single rotor design with pinion gear translating torque properly to the eccentric shaft, which serves a similar function to the cam shaft in a piston-driven engine. Normally an engine would have multiple rotors applying energy to the eccentric shaft (called so because it’s got offset lobes to make up for the way the rotors spin slightly off-center in the housing). But iron was short around here, so our first engine would only have one rotor, fed by a bladder of natural kerosene from the bog springs.

There’s a lot of advantages to rotary engines that made them ideal for material-starved goblins. They could be built small and light, they had only a handful of moving parts, and they could burn the gnarliest, filthiest crud-laden bunker fuel mixes. Which meant a rotary engine should gobble up the impure raw bog sludge and come back for seconds.

If they’re so great, why aren’t they more popular, you might ask.

Well, just like my first roommate in undergrad, they’re weird and a bit gross. It’s tough to get their output clean enough to pass emissions standards without reducing the output below a useful level or making the engine prohibitively expensive. Luckily, I’d not yet encountered Rava’s version of the EPA. It was time to get our rotary on.

I watched Sally get the engine bolted to the test block with brass bolts the Ifrit had supplied, while two wranglers came up with the custom spark plugs held at arms length as they cracked and popped. What they really were, was small ceramic jars with a pair of tesla wasps inside, ornery and sparking. The bog had supplied everything we really needed to create an engine. Ringo didn’t know the goldmine upon which he sat. He had been using the slick-sheen oil to grease down his hair when I’d met him. He was lucky he hadn’t gone up like a chimney when I pulled my escape.

The engineers took the plugs from the wranglers and fitted them to the side of the engine casing. The pops and snaps grew muted. With the business end of the tesla plugs pointed toward something inert, Sally herself brought up the bladder of fuel. And, fun fact, it was an actual bladder from some poor creature. I fitted it to the valve on the fuel intake and gave a little squirt to make sure the flow was good.

“Promo!” I called. The burly noblin trundled up with a leather band that he wrapped around the shaft of the motor. Our throttle was just a simple brass wrench the Ifrit had given us, connected to another valve. I pulled on it to open it up.

“Ready, boss,” said Promo.

“Pull it!”

The noblin chief yanked on the leather band, spinning the shaft, and with it, the rotor.

Pop.

A tiny puff of smoke came out the exhaust port and the engine went still.

Stolen content warning: this content belongs on Royal Road. Report any occurrences.

Prometheus leaned down and looked at it. “What went wrong?” he asked.

“Nothing,” I said, practically giddy. “It turned over first try!”

I flipped the fuel valve choke to on and had Promo repeat the process until it popped again to clear the fuel left in the system. Then I gave it slightly less fuel.

I learned a lot about small engines when I’d gotten my motorcycle—a hunk-of-junk old Triumph that had been neglected by the first owner. It wasn’t a rotary engine, of course, but most of the principles were the same. The hardest part is getting the fuel-air mix right. Too much fuel meant not enough air. I needed to lean the mixture.

Unless you want to give it to me based on theory, I suggested. It did turn over, after all.

Stingy system. I gave the nod to Promo, who took the belt again. This time, when he yanked it, nothing happened.

I frowned. “Hmm. Armstrong?”

“Yeah boss?” my bodyguard asked.

“Help him out, put those muscles to use.”

Armstrong flexed his arms and cracked his knuckles, strutting over to the eccentric shaft and taking the belt. Despite noblins being bigger, hobgoblins were still stronger. It seemed like noblins were more suited to cerebral pursuits while hobgoblins tended to be more physically skilled variants. He let out a grunt and yanked on it, and I heard the wood of the stump strain under the mounting bolts.

Pop, pop.

Closer. But we needed more torque on the shaft. At the flying field I’d seen more than a few old timers hand-start their planes, be it via strap, hand-held starter, or just grabbing the tip and whipping the thing down. Seen a few broken fingers, too.

I had a second belt brought up, and this time Promo and Armstrong stood on opposite sides of the engine and yanked at the same time. Unfortunately, I’d been fiddling with the engine and didn’t realize they’d wrapped in opposed directions, so all that happened was they both slipped and bonked their skulls on the shaft.

Once the two knuckleheads got that issue sorted out, and I doublechecked to make sure they were spinning the rotor in the right direction, I had them try again.

Pop pop pop POP POP pop pop… pop.

I moved the throttle, trying to give it enough fuel, but it still just didn’t have the initial gusto with only goblin muscle. I could tie a longer band around it and have a few goblins take a swan dive off the bluff, but we weren’t going to be able to rely on blue fuzzy counterweights every time we wanted to crank an engine up to idle. A decent chunk of the crowd started to disperse, interest waning. But Taquoho hovered nearby in his new ultralight helicopter vessel. He’d been flying around in it almost since I’d given it to him, with only brief breaks to rest. He’d been a right menace with the thing, flying all around the bluff.

“I’m not sure what the issue is from out here. Would you like me to investigate from within?” he asked.

I cocked my head. “Would that be alright? I don’t want to put you at any risk.”

By way of answer, Taquoho touched down and slid from one device to the other, infusing the rotary engine with a pale blue flame. We went through the startup procedure again, getting a handful of pops.

“I’m afraid I’m not an expert at this manner of artifice,” said Taquoho. His voice came out the exhaust port. “But it seems that the angular piece is struggling to gain enough speed from the expansion of hot gasses to sufficiently sustain the cycle.”

“Yeah,” I sighed. “That’s what I figured.”

Armstrong and Promo were huffing and puffing after their multiple attempts. Even with two strong variants working together, it was looking just like with the early attempts at a pedal-powered glider, goblin muscle just wasn’t up to the task. Even Armstrong was probably only matched in strength to maybe a 12-year old boy, and he was the strongest goblin in the entire tribe. And when I was 12, I’d had a hell of a time trying to pull-start our old, battered lawn mower. This rotary getup wasn’t nearly as well refined as a gas mower engine. I kicked the stump in frustration. What I wouldn’t give for a battery-powered starter. But turning our raw materials into a battery and brushed motor was, if anything, a more time-consuming task than just figuring out the solution.

Taquoho streamed out from the exhaust port and back into his little aircraft, as though worried one of his kin might steal it if he left it idle too long. The blades began to spin, and after a moment to gain momentum, he was off the ground again. I watched him climb into the air. At least something had worked today.

I had worried that the static friction of his rotors would be too much to overcome. I’d considered co-opting an old mid-1900’s design from before they really got helicopters figured out and most people thought auto-gyros were the future of rotary aviation. There’d been one design in my history of aviation class that was really ridiculous. Instead of power from a central hub, the static friction had been overcome by…

Huh…

It had been overcome by rockets.