Kawanishi N1K Kyōfū / Shiden Design Evolution

Kawanishi N1K1 Kyōfū 強風 “Mighty Wind” (Allied reporting name “Rex”) was designed to an Imperial Japanese Navy specification for a floatplane fighter to operate in the Pacific where conventional airfields were unavailable.  The prototype first flew on 06MAY42.  The prototype featured contra-rotating propellers to eliminate the torque of the 1,460 hp Kasai 14 engine.  The color of the prototype is debated – silver dope, light gray, and orange-yellow are each represented in various profile artwork.
Problems with the propeller gearbox lead to the substitution of a more conventional three-bladed propeller for the production Kyōfū series.  Powered by a 14-cylander Kasai 13 engine, 97 were produced.
The Kyōfū served operationally in Balilpapan, Borneo, and finished the war on Lake Biwa defending the Tokyo area.  This example is from the Sasebo Kōkūtai and is fitted with a more conventional engine arrangement, it features individual exhaust stacks and a standard propeller spinner.
Even before the first Kyōfū took flight, Kawanishi engineers realized the potential of the design as a land based fighter and proceeded with development as a private venture.  Retractable landing gear were substituted for the floats, and a Homare 11 engine was installed, driving a four bladed propeller.  Armament was increased by adding two additional 20 mm Type 99 Model 2 cannon in gondolas under the wings.  The land based prototype first flew on 27DEC42.  It was designated the Kawanishi N1K1-Ja Shiden 紫電 “Violet Lightning” (Allied code name “George”).
The 201 Kōkūtai deployed to Cebu in the Philippines where several of their Shiden were disabled or destroyed on the ground by American fighters.  The design was plagued by engine problems and weak landing gear, but was reported to be a worthy opponent when in the air.
The capture of the airfield on Cebu afforded the Americans to get their first detailed examination of the new fighter.  This shot affords an excellent view of the cannon gondola under the wing and the interior of the wheelwell.  Note the extreme length of the landing gear legs, a weak point of the design and continual source of problems.
A redesign of the wing to house all four Type 99 20 mm cannon internally resulted in the N1K1-Jb.  Most photographs of operational Shiden show the 400 liter belly tank fitted, as seen here.
An N1K2-Jb shown on a rainy airfield apron.  The twin 20 mm guns in the wing are clearly seen, as is the landing gear position indicator projecting up out of the wing over the landing gear leg.
Kawanishi took the design in hand once again, lowering the wing position and deleting the fuselage mounted 7.7 mm machine guns.  The result was the N1K2-J Shiden-Kai, and it possessed performance on par with contemporary American fighters.  This is an aircraft of the most famous Shiden-Kai unit, the 343 Kōkūtai, and one of its most famous pilots, LT Naoshi Kanno, taken in April 1945.  The white 15 in the Hinomaru is a temporary marking used for training. Compare the sizes of the vertical stabilizers of these aircraft.
A trio of 343 Kōkūtai Shiden-Kai in flight, LT Kanno’s aircraft is to the left.  The two yellow command stripes were applied on Kanno’s orders in hopes they would attract American aircraft to him.
The first one hundred Shiden-Kai produced had a broad vertical stabilizer, a hold over from the design’s origins as a floatplane.  Subsequently it was realized that the size of the stabilizer could be reduced, and for the remainder of the production run the Shiden-Kai was fitted with a smaller rudder.  Here is an example with a small rudder seen in the U.S. after the war.
Four Shiden-Kai survive in museums today, three in the U.S. and one in Japan.  All are late production examples with the smaller vertical stabilizer.