Preparations for testing the quarter-scale model of the biplane type Blow Floater were complete.
"All right, wake up! Begin the test!"
Roa Eisker's voice rang out, and the model's Blow Engine sprang to life.
A slightly high-pitched intake whine resonated as the model slowly lifted into the air.
In no time at all, it reached an altitude of roughly ten meters.
"Great! Phase one—liftoff is a success!"
Roa's voice brimmed with joy.
"Pilota, move forward slowly. Make a U-turn just before the far edge of the plaza and come back. Nice and easy."
Following the command, the model began to cruise forward at a gentle pace.
It moved at roughly four kilometers per hour—about walking speed.
The plaza behind the academy measured about a hundred meters square, so the craft reached the far side in roughly a minute and a half.
There, rather than a sharp turn, it traced a wide, 180-degree arc and slowly flew back.
"Yeah, looks like the handling is in top shape."
Rasnat Heilbronn muttered to himself as he watched the craft.
"That Blow Floater is remarkably stable..."
Groma Tray, who was Lordtoss's disciple and had seen his master's Blow Floater several times, murmured in admiration.
"Hmm, flying vehicles look like a lot of fun, too."
Eira seemed to have developed an interest in aircraft.
"So this is just a model."
"I'd love to see a full-scale version."
"If we have golems pilot the real aircraft too, wouldn't that cut down on human error?"
The researchers from the Go-lab seemed to have all sorts of ideas running through their heads.
"All right, pick up the pace. Turn left and circle the grounds."
Having verified the craft's stability, Roa Eisker ordered an increase in speed.
The model accelerated sharply, reaching around twenty kilometers per hour—roughly the speed of a bicycle.
"Oh, looking good."
Watching the model bank smoothly into a wide left turn, Jin could tell at a glance that it was well-crafted.
(Yeah, both the biplane and the small golem are exceptionally well-made. This definitely holds a lot of promise...)
After several circuits around the plaza, Roa issued his next order.
"Carefully bring it up to top speed. But don't push it too hard."
In response, the model accelerated even further.
"Oh, that's pretty fast....Reiko, what's our speed?"
"Let's see... Exactly thirty-eight kilometers per hour."
"I see....Well, the speed won't scale up by a clean four times, but fifty kilometers per hour seems like a safe bet for the full-scale machine."
Biplanes generated significant drag, putting them at an increasing disadvantage the faster they flew.
"If we're prioritizing safety, a cap of around sixty kilometers per hour sounds about right."
This sixty-kilometer figure came from the standard speed limit on public roads back when Jin lived in modern Japan.
In truth, roads with sixty-kilometer limits were relatively rare, with limits of fifty or forty kilometers being far more common.
"You're getting a bit ahead of yourself, Jin-dono..." Roa said, having overheard the exchange with Reiko.
"No, not at all. Using a model to predict the performance and finish of the final product is an important part of the process."
Hearing Jin's explanation, Roa nodded in understanding.
"When a craft gets larger, its oscillation period lengthens, so you have to factor that in as well."
"That is true."
On a related note, beginners learning to fly radio-controlled aircraft were often said to have an easier time getting used to the controls with a somewhat larger model.
Practicing with smaller models just because they were cheaper supposedly took longer to master... or so the saying went.
Jin had never been able to afford such model airplanes due to his financial situation back then, but he had watched acquaintances fly them several times and had listened to them ramble on about the hobby.
"Still, it's a bit frustrating that speed doesn't simply scale up fourfold."
Something about air resistance and fluid dynamic constants... apparently. Jin only had a high school education, so it irked him a little that he didn't know the exact mathematical formulas.
With brief landings interspersed to inspect its components, the test flight concluded safely after about an hour.
"A solid success."
Roa Eisker was in high spirits.
"It was a massive success!"
Zora Himmel was in an even better mood, utterly over the moon.
"Yes, yes, our collaboration was well worth the effort!"
Rasnat Heilbronn was looking just as delighted.
"Flying through the sky in a machine we built ourselves sounds like a blast," Eira murmured softly.
Jin figured that after spending so much time buried in golem research at the Go-lab, it was only natural for them to want to branch out into other fields.
After all, Jin himself was the type to dip his hands into every possible craft.
"If you just want to fly, I have the Blow Floater I brought with me," Jin offered.
"Oh, awesome! I'd love to take a ride!" she replied instantly.
The researchers from the Aviation Research Lab quickly chimed in as well.
"Ah, yes! We'd love to see your machine too, Jin-dono!"
Is this the perfect chance to unveil the new aircraft? Jin thought, checking the time.
"It's only ten thirty. In that case, we have time for a quick look."
With that, he told anyone interested to follow him to the airfield where the Hurricane was parked.
The airfield was a bit of a trek, but since everyone hurried over at a brisk jog, they arrived in about ten minutes.
"...All right then, let's bring out the Southern Cross....Hope!"
"Yes, Master."
At Jin's command, Hope immediately boarded the Southern Cross and started up the Blow Engine.
After releasing the support frame via remote control, the craft floated gently into the air before making a smooth touchdown on the airfield.
"Ooh!"
"Whoa, that's incredible."
"As expected of Jin-dono."
"Well, this is the Southern Cross. By arranging the circular wings like this, it's designed to maximize both stability and maneuverability."
With the engineers gathered around, Jin began his walkthrough of the Southern Cross.