On April 9th, barely finishing his breakfast, Jin dashed out of the laboratory to conduct a test flight of the Eagle Unit 2.
"Father, please let me be the test pilot."
Reiko firmly volunteered.
"All right, I'm counting on you."
"Yes!"
Jin then called Hope over.
"Hope, you pilot the Eagle Unit 1. I'll ride along with you."
"Understood."
He planned to trail the Eagle Unit 2 in the Eagle Unit 1 to observe its subtle movements and handling in real time.
This method was only possible because a Blow Plane flew at such low speeds.
The Eagle Unit 1 carrying Jin was already waiting aloft.
"Well then, here I go."
Reiko contacted him over the manacam.
"All right, go!"
The Eagle Unit 2 lifted off the ground.
"Stability: nominal."
"Looks like it."
Observing from above, Jin saw no problematic behavior whatsoever as the Eagle Unit 2 demonstrated a perfectly steady takeoff.
"No instability during liftoff."
The Taube, Eagle Unit 1, and Eagle Unit 2 all shared the same circular wing design, but their curvatures differed.
While the wings of the Taube and Eagle Unit 1 were curved convexly upward, the Eagle Unit 2's wing was almost entirely flat. Because of that, there was a greater loss of blown air when generating lift.
To compensate, Jin had increased the output of its levitation Blow Engine.
"Transitioning to level flight."
"All right, go ahead!"
After climbing to an altitude of about fifty meters, the Eagle Unit 2 leveled out into horizontal flight.
"First, setting propulsion engine output to ten percent."
"Yeah, looking good."
Here, the benefit of the flattened circular wing made itself known.
On a Blow Floater or Blow Plane, the main circular wing generated the vast majority of aerodynamic drag.
By flattening it out almost completely, its speed had improved.
Even with the same propulsion engine, its velocity was up by over forty percent.
"Testing directional turns."
Next, Reiko proceeded to test its maneuverability.
"Oh, it's turning on a remarkably tight radius."
Making the half of the fuselage that served as a vertical stabilizer movable, allowing it to double as a rudder, had paid off.
However...
As they pushed the limits of how tightly it could turn, the Eagle Unit 2 suddenly jerked, destabilizing its attitude.
"My apologies, Father. It stalled."
"Looks like it. Hmm, seems tilting the circular wing too far into the turn triggered the stall."
Jin felt a pang of disappointment, realizing that prioritizing agility had severely compromised its stability.
After running through the rest of the handling checks, Jin decided to call an end to the trial.
"All right, bring it down for now."
Both the Eagle Unit 1 and Eagle Unit 2 touched down in the plaza outside the laboratory.
"Hmm, I suppose that's the limit for this design..."
Jin reflected that, in an effort to make it more responsive, altering the shape had turned it into an overly finicky machine to handle.
"I suppose it has its place, but still..."
Since it hadn't achieved the performance he had envisioned, Jin wore a troubled frown.
It simply hadn't turned out the way he hoped.
"Father, was it not to your liking?"
Reiko looked a bit dejected.
"No, it's not your fault at all, Reiko. It's a flaw in the design."
Jin comforted her with a reassuring smile.
"It might be fine for racing, but it's a bit too impractical for everyday use."
Jin judged it unsuitable to bring along to Avalon.
"Hmm, in that case, maybe I should try out that other idea..."
Jin had been harboring another concept for a Blow Plane—one built from the ground up rather than modified from previous designs.
It was a Blow Plane equipped with four circular wings arranged in the front, rear, left, and right.
The front and rear circular wings were small, while the left and right ones were large.
The Pegasus 1 Jin had built before featured lift-generating Magi Jet Engines at both wingtips, but this design placed them at the front and rear as well.
It resembled what modern Japan would call a quadcopter drone, though rotated forty-five degrees relative to its direction of travel.
The intent was to control pitch up and down using the front and rear circular wings, while altering roll and yaw with the left and right circular wings to execute turns.
A short fuselage and cockpit would be set in the center, bridging the left and right circular wings.
Combining the surface area of all four circular wings roughly equaled that of previous Blow Planes or Blow Floaters.
Consequently, the footprint of the aircraft itself would be larger.
Since there was still time before lunch, Jin decided to build a prototype along those lines.
"Reiko, lend me a hand."
"Yes, Father."
With Reiko assisting him and several Smith golems called in to help, Jin's idea took physical form in about an hour.
This time, the circular wings were curved convexly upward.
After running through a full inspection, Jin spoke up.
"There's still about thirty minutes until lunch, so let's run a quick test."
True to form, once he built something, he couldn't wait to test it.
"In that case, allow me."
"Yeah, I'm counting on you."
Since Reiko volunteered again, Jin left the controls to her.
"Vary the output of the left and right Blow Engines when turning. Use the front and rear for climbing and descending."
"Yes, understood."
With the control mechanisms still unproven, they had to rely on Reiko's lightning-fast reaction speed. It was still too risky to entrust this to Hope.
"Be careful."
"Yes, Father."
Because it utilized an unprecedented new attitude control system, caution was paramount. Jin summoned fifty Smith golems to deploy a shock-absorption barrier just in case of a crash.
It was the same type of barrier used during the air race.
"All right, go!"
"Reiko, taking off!"
The prototype's Blow Engines roared to life, and the aircraft slowly began its ascent...