January 30, 3900 in the continental year of the existence of the complex of Jin.

It is the last day of January in the Ars world calendar.

In the sky of , which is located in the southern hemisphere, flying objects of various shapes and sizes were flying around.

"Oh!　That's good work!"

"Hmm, is it still a little unstable?　Maybe I should increase the wing dihedral angle by 1 degree.

"Not so bad. It would be nice if we could increase the speed by another 10%. ......

The monologue of those who are flying the plane is leaking out.

"Hmmm, you guys are really good!"

Looking up in admiration is Nido Jin, the <>.

< and respect him. However, Jin himself is not fond of this terminology, so he has settled for being called <>.

And tomorrow is the day of the <>.

And tomorrow is the day of the <>, so the participants are making final adjustments to their planes.

I like the fact that we are all like a family, so there is no need to hide or cheat at this point in time.

The final regulations (rules for participation) are as follows

Size: Must fit into a cube of 1.5 meters on each side.

Weight : No limit.

Material ：Materials found on must be used.

Propulsion: Must be powered by a rotating engine with a screw propeller. The number of engines is not limited.

Floating type: Lift force must be generated by the wings. Direct levitation using a propeller will be disqualified.

Shape: No restrictions.

Cockpit type cockpit must be used as specified by Jin.

Special note: The provided by Jin must be used.

That is all.

Since this is the first competition, Jin thinks that there may be some imperfections.

If we notice anything during the competition, we will add it to the list as appropriate.

In the conceptual stage, we thought that the size of the robot should be within a cube of 1 meter on each side, but we decided on this size after considering that a small robot would not be stable and would not be easily visible from the ground.

I thought about making it 2 meters, but decided against it because it would be much taller than Rubina's height (123 cm).

The cockpit-type pilot's seat designated by Jin was used, based on the previous car race, so that there would be little difference in the way the car was piloted.

In addition, the provided by Jin must be used, in order to allow the pilots to fly the plane as they wish, without complicated attitude adjustments.

The competition will consist of the following events: 1.

Speed competition (high speed): The competitor who flies around two poles and takes the shortest time is the winner. The first place is 100 points, the second place 80 points, the third place 60 points, the fourth place 40 points, the fifth place 20 points. The shorter time is the higher rank. 2.

Speed competition (low speed): The contestant who has the longest time to complete the lap around the 2 poles will be placed first. The winner will be awarded 100 points for 1st place, 80 points for 2nd place, 60 points for 3rd place, 40 points for 4th place, 20 points for 5th place, and so on. The longest time is the higher rank.

The contestant will be disqualified when he/she touches the ground. 3.

Aerobatics (Pattern): The contestants will draw the prescribed flight pattern and compete for the accuracy of the pattern.　Scoring will be done by the management brain of < on . 100 points is the maximum score.

Aerobatics (free): free flying and evaluation of the performance.　All spectators are scored out of 100 points. (Each spectator has 100 points / number of spectators). 5.

Race: The competitors compete for the fastest time around a course with a ring of gates. If a competitor fails to pass through the gate, he/she will be disqualified. However, it is allowed to turn around and go through the gate again, 100 points for 1st place, 80 points for 2nd place, 60 points for 3rd place, 40 points for 4th place, and 20 points for 5th place.

As a bonus,

6. design: All the spectators are asked to score the appearance, gimmick, performance, etc. The maximum score is 100 points. (Each spectator has 100 points/number of spectators).

The score is 100 points (each spectator has 100 points/number of spectators).

is surrounded by wards, the strength and nature of which can be adjusted to make it impervious to outside influences such as wind and rain.

Therefore, the competition was to be held in windless conditions, and it was an advantage not to have to worry about unnecessary things such as countermeasures against gusts of wind.

The competition was held in windless conditions, which was an advantage of not having to worry about gusty winds.

Of course, Jin also participated as a guest. Or rather, he was eager to participate.

Jin built a variable wing aircraft.

The main wing has three layers,

At low speeds, the three layers slide together to widen the wing area and reduce the wing loading, thus increasing lift at low speeds.

At high speeds, the three overlap each other and become a retracted wing to enable the aircraft to attain high speeds.

The propulsion system is a pseudo-jet engine using a ducted fan.

A ducted fan is a cylindrical exterior (called a duct or nacelle) in which the engine and propeller are mounted.

Since the fan (propeller) diameter is smaller, the engine will inevitably rotate at higher speeds and may be more suitable for models than for actual aircraft (efficiency decreases when the propeller tip exceeds the speed of sound).

The engine, which tends to be heavier than the actual model, can be placed near the center of gravity, depending on the design, which has the advantage of increasing maneuverability in the air.

However, it also has disadvantages such as greater resistance at high speeds and higher costs.

The main reason for Jin's adoption of this engine was to emphasize speed.

As with jet engines, the nozzle on the exhaust side can be narrowed to increase the injection speed, which in turn leads to higher speed.

With propeller propulsion, it is impossible to fly faster than the wind generated by the propeller, but this is possible with a ducted fan. Taking this one point, we decided to ignore the other disadvantages or to solve them technically.

This is probably due to a misunderstanding on the part of Jin.

The thrust of propeller propulsion is not the wind generated by the propeller, but the lift force of the propeller itself, and the wind is generated as a result.

And ducted fans are supposed to be disadvantageous at high speeds, but ......nin is just unaware of this due to his own manufacturing capabilities.

"Oh, that looks nice."

Sitting in the cockpit-type pilot's seat, Jin was enjoying the view of the actual aircraft.

There is a magic screen in front of the cockpit, which displays images sent from the aircraft in real time, giving the pilot a realistic feeling of flying the aircraft.

This time, the Magic Eye installed in the sky above the aircraft allows the pilot to switch to a bird's-eye view of the aircraft.

The reason why we have been free-flying until the day before is to get used to the feeling of the flight.

I am still very much looking forward to the next flight.

Jin-sama's plane is really amazing.

Rubina was in the pilot's seat to the right, one seat away from me, doing a final checkup ......, or rather, a familiarization flight.

Her aircraft is a so-called with triangular wings. It is a plane that achieves a high balance between stability and high speed.

It is, of course, suitable for high speed, but surprisingly, it can also fly at low speeds.

In such a case, the nose of the plane is raised to a large angle of attack against the direction of travel, but the delta wing can handle angles of attack that would cause stalling in the case of an ordinary tapered wing.

This is probably the reason why origami airplanes can fly surprisingly slowly. The light weight is the most important factor. .......

Delta wing planes are very agile and can easily perform a "roll" or "twist" flight.

"Ugh......I'm still dizzy...... and it makes me sick. ......<>"

Rubina is committed to piloting from the passenger's point of view, which is why she is trying to get used to <>.

Whenever she feels sick, she applies <> to herself and heals herself while practicing.

He was practicing while healing himself.

"Yes, yes, yes, yes, yes, yes, yes, yes, yes, yes, yes, yes, yes, yes, yes, yes, yes, yes, yes, yes.

<

It was designed to provide lift at low speeds and high turning performance.

The increase in weight and drag is compensated for by the high power propulsion system.

We are now testing the stability at low speeds, and it is very stable.

The other participants have also completed their tests and practices, and are eager to compete in the main event on the following day.

The island of Onogoro is slowly sinking into the evening darkness after the preparation of the venue was completed.