During the banquet at Jin Nidou Castle, Rubina sought Jin out for some advice.
She wanted to know whether Blow Floaters and conventional aircraft were fundamentally incompatible technologies.
It hardly seemed like appropriate party banter, but since Rubina was too young to drink, it was only natural for her mind to wander elsewhere.
Besides, Jin personally loved conversations like this.
"Rather than seeing them as incompatible, I consider it the next evolutionary step," he explained.
"An evolutionary step?"
"Right. Taking Marikka's Blow Floater as a foundation and developing it further toward maneuverability and speed... That's what a Blow Plane is."
"A 'Blow Plane'?"
Rubina tilted her head at the unfamiliar term.
"Ah, yeah. I figured that's what we could call a Blow Floater that uses aerodynamics for attitude control and steering."
"A 'Blow Plane,' huh... That sounds kind of cool."
"You think so?"
Jin smiled, then added, "In a way, you could also say the Hurricane is just a Blow Floater scaled up to increase its transport capacity."
While the Hurricane was shaped like an airship, its underlying operating principle was that of a Blow Floater.
"Ah, that's true... The scale is just so entirely different that I almost forget sometimes."
Rubina giggled.
At that moment, Lordtoss strolled over to join them.
"Are you talking about the Blow Plane? Everyone was wide-eyed seeing your Taube Kai in action, Jin-san."
"Is that so? Personally, I'd like to experiment a lot more with the shape of the main wing."
The airflow generated by a Blow Floater's blow engine was not limited to a circular profile. It could easily be shaped into an ellipse or even a square.
Since it could be adjusted simply by altering the magi-formula scripting, its greatest asset was that it added no extra weight.
"That way, we could make airframes shaped much closer to a tailless aircraft, and if we manage that, we can leverage aerodynamics to push maneuverability even further."
"Ah, that sounds like so much fun!"
"I want to make one too!"
Both Lordtoss and Rubina chimed in, their enthusiasm practically bubbling over.
"I see. Well then... since today is meant for celebrating, let's find some time to sit down and talk through the details starting tomorrow."
"Okay!"
"Sounds great to me."
With that decided, the banquet carried on in high spirits.
Since the guests were practically family at this point, not a shred of ill will lingered from the competition.
Praising each other's technical triumphs and pointing out areas for improvement, the representatives of the Nord Federation enjoyed themselves immensely.
Eris and Freddie remarked that this was their first time ever witnessing, let alone participating in, such a lively gathering at Jin Nidou Castle.
"The atmosphere here is truly wonderful, isn't it?"
Jin felt relieved seeing how much they were enjoying the festivities.
As an amusing side note, hearing the cheerful noise drifting from Jin Nidou Castle, several villagers from Kaina Village came up to see what was happening; Butler B and C tactfully treated them to complimentary drinks.
Word quickly spread, and villagers trickled in one after another throughout the evening.
The following morning, Lordtoss and his group departed for the Nord Federation aboard their Blow Floaters.
The assistants, family members, and Sion who couldn't fit aboard were escorted home by Jin aboard the Hurricane.
Rubina, Amanda, and Greena remained behind in Kaina Village, choosing to spend the next two or three days relaxing alongside Freddie and Eris.
Of course, since Eris and Freddie were the official lords of Kaina Village, they were technically the ones hosting Greena's party.
"Please, make yourselves right at home," Eris told them.
Since it had been a while since they last saw each other, Greena and Freddie were entirely absorbed in reconnecting, while Rubina holed up in the Jin Nidou Castle Library to pore over research materials.
Specifically, she was reading the books concerning the "aircraft" of Jin's original world.
"Hmm, so that's how it works..."
The content centered primarily on what Jin remembered about model airplanes, supplemented by the results of various practical experiments he had conducted in this world.
Because the notes were practical rather than purely theoretical, they were ideal for Rubina's purposes.
"I see, I see..."
When she had skimmed them in the past, she had thought she understood the concepts, but rereading them now with hands-on crafting experience brought a flood of new revelations.
"Even though rudders and ailerons both serve to change the craft's orientation, their mechanics are completely different..."
With model airplanes, turning the rudder was enough to bank and swing the craft around.
In reality, however, banking the aircraft induced a sideslip, and that lateral force acted as centripetal force to pull the plane through a turn.
In practice, ailerons and rudders had to be used in tandem.
"Model airplanes are small and light, so a rudder alone was sufficient, but full-scale aircraft are large and heavy, which is why both controls are necessary... I suppose."
Rubina interpreted the concepts in her own way as she read on.
"Balancing a tailless aircraft seems tricky, though. Jin-sama really made it look effortless..."
She gained a much deeper appreciation for the elevons Jin had incorporated into his design—the seamless combination of ailerons and elevators.
"Jin-sama's flight really was incredible, wasn't it?"
"Yes, truly."
Freddie and Greena were reflecting on the breathtaking display of craftsmanship they had witnessed, filled with admiration.
As topics for a date went, it was utterly devoid of romance, but since both were engineers at heart, neither minded in the least. They were simply two of a kind.
"I'd love to fly freely through the sky myself someday."
"Me too."
Greena readily agreed, prompting Freddie to look at her in surprise.
"Wait, Greena, you haven't flown in an aircraft of your own making yet?"
"No... Well, to be precise, I've done short test hops, but never anything that let me soar around freely like that."
"I see. In that case..."
Freddie gazed into the distance for a moment before turning back to her with a gentle smile.
"If you'd like, would you want to develop one together?"
"Oh, I'd love that."
Greena eagerly jumped at the offer.
"Aiming for Jin-sama's level right off the bat would be reckless, so I want to build up our skills until we can reliably make a craft that flies safely."
"I completely agree."
For now, Greena was still the more proficient magi-craft engineer, but she knew that at this rate, Freddie would soon catch up and surpass her.
Even so, she accepted that natural progression, finding quiet satisfaction in how genuinely happy she felt watching the person she cared for grow so capable.
Perhaps it was that very gentleness of character that had caused her to narrowly fall behind Rubina during the Magi Craft King and Magi Craft Queen selection matches.
"In that case, shall we use the workshop in Jin Nidou Castle?"
Naturally, that depended on getting Jin's permission first, but he was hardly the type to turn down an earnest request like theirs.
"Yes, gladly."
Greena agreed with an eager nod.