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Normal
Main wingThe main wing for the Kyofu was a mid-wing configuration that had less interference resistance with the fuselage and was less likely to be hit by water splashes during takeoff. A laminar flow wing was also adopted as the wing shape. A laminar flow wing is a wing shape that delays the turbulent transition of the airflow over the wing and reduces air resistance, and it was expected to be effective in increasing speed. At the time, various shapes of laminar flow wings were researched and were also used on several military aircraft (such as the P-51 and the Saiun), but the one adopted for the Kyofu was the LB-type laminar flow wing invented by Professor Ichiro Tani of Tokyo Imperial University (now the University of Tokyo). The maximum thickness position of a normal wing's cross section is around 30% of the wing chord, but the maximum thickness position of the LB-type laminar flow wing is at about 40% of the wing chord, which makes the pressure gradient positive and expands the area where the airflow flows stably (the wing of the Shiun is also an LB-type laminar flow wing). In order for a laminar flow wing to be effective, the wing surface must be very smooth, but there is also a view that it may have been difficult to achieve the necessary precision with the machining technology of the time . The Kyofu that required high speeds also meant high wing loading, and in order to balance takeoff and landing performance, the wing root angle was an unusually large 4 degrees for a fighter, and on the first flight, as soon as the flaps were retracted, turbulence from the wing root stall struck the horizontal stabilizer, causing vibrations. As a countermeasure, the fillets were enlarged.
Main wing
The main wing for the Kyofu was a mid-wing configuration that had less interference resistance with the fuselage and was less likely to be hit by water splashes during takeoff. A laminar flow wing was also adopted as the wing shape. A laminar flow wing is a wing shape that delays the turbulent transition of the airflow over the wing and reduces air resistance, and it was expected to be effective in increasing speed. At the time, various shapes of laminar flow wings were researched and were also used on several military aircraft (such as the P-51 and the Saiun), but the one adopted for the Kyofu was the LB-type laminar flow wing invented by Professor Ichiro Tani of Tokyo Imperial University (now the University of Tokyo). The maximum thickness position of a normal wing's cross section is around 30% of the wing chord, but the maximum thickness position of the LB-type laminar flow wing is at about 40% of the wing chord, which makes the pressure gradient positive and expands the area where the airflow flows stably (the wing of the Shiun is also an LB-type laminar flow wing). In order for a laminar flow wing to be effective, the wing surface must be very smooth, but there is also a view that it may have been difficult to achieve the necessary precision with the machining technology of the time . The Kyofu that required high speeds also meant high wing loading, and in order to balance takeoff and landing performance, the wing root angle was an unusually large 4 degrees for a fighter, and on the first flight, as soon as the flaps were retracted, turbulence from the wing root stall struck the horizontal stabilizer, causing vibrations. As a countermeasure, the fillets were enlarged.
