The Kawanishi N1K1-J Shiden was a
single-engine Japanese fighter that entered service in the closing
stages of the Second World War. It became one of Japan's most successful
land-based fighters despite its unlikely origins. Facing overwhelming odds, it didn't get
the recognition it perhaps deserved.
The Kawanishi Aircraft Company specialized
in floatplanes and flying boats, with the H6K "Mavis" and the H8K "Emily" being
probably the most well-known of its products. The N1K1 Kyofu was a floatplane fighter
that flew for the first time on May 6, 1942. Known by the allied reporting name
of "Rex", the Kyofu’s main purpose was to support amphibious landings where land-based
fighters had no airfield to operate from. But when the Kyofu made its operational
debut, the Japanese advance had halted, and it quickly became clear that such an aircraft
would have less use than a land-based interceptor. For this reason, only 97 were ever produced,
with the last few delivered in March 1944.
Meanwhile, the Kawanishi Company had been working
on a land-based version of the N1K1 since December 1941. This version’s prototype made its maiden
flight on December 31, 1942. Initially, it was received with suspicion by the Imperial Japanese
Navy Air Force since it was a private venture and had little input from that organization, but,
after a thorough evaluation of the prototype in July 1943, it proved to be superior to all
Japanese operational fighters at that point, and so, Kawanishi received the go-ahead and the N1K1-J
was officially born. It was baptized Shiden, Japanese for Violet Lightning, and it started
equipping units in early 1944 after some delays.
The Shiden was baptized with the allied-codename
"George." It was fitted with an 18-cylinder Nakajima NK9H Homare 21 radial engine that could
develop 1990 hp, connected to a huge four-bladed propeller with a diameter of almost 11 ft. This
engine was based on the Nakajima Sakae used in the A6M2 Zero, and, even though it was quite powerful,
it was also troublesome due to unreliable carburettors and the usage of poor-quality fuel.
It was armed with four 20 mm (0.78 in) Type 99 Model 2 Mk 4 cannons and two 7.7 mm (0.303
in) Type 97 machine guns. It had automatic combat flaps that would retract or extend when
needed, relieving the pilot from operating them. This system was a feature of late-war Kawanishi
fighters. It was highly appreciated by pilots, and testing proved that it gave an edge in dogfights.
The N1K1-J saw action for the first time in the fall of 1944, mainly in the Philippines,
opposing the American campaign to retake them. It flew 303 sorties there, and its pilots
claimed more than 40 air victories.
Still, the Shiden’s operational debut quickly
exposed a huge flaw in its landing gear. Due to its origins as a floatplane, the Japanese
fighter had a wing that consequently joined the fuselage at a mid-point. Its huge propeller also
begged for a large ground clearance. Consequently, the landing-gear "legs" were quite long and
complex, leading to a large number of accidents with a collapsed undercarriage. Due to this, the
Shiden could only be operated from paved runways.
The number of accidents was high, but Kawanishi
had always seen the N1K1-J as an interim fighter on the way to the definitive version, the
N1K2-J Shiden-Kai, with Kai meaning modified. This improved version flew for the first time on
the last day of 1943. By June of the following year, the first examples left the factory, and by
early 1945, the Shiden-Kai was equipping frontline units. The improved version differed considerably
from its progenitor. The main differences were:
allowing for smaller landing-gear
"legs", increasing their sturdiness.
Japan had few fighters that could adequately
intercept the B-29s that were becoming common over the Japanese main islands, and the Shiden-Kai
was one of the biggest threats Japan could muster against those. So, the Imperial Japanese Navy Air
Force placed considerable hope in the Kawanishi fighter, and, in January 1945, a new unit was
created. Named the 343rd Kokutai it was composed mainly of veteran pilots. It was entirely equipped
with Shiden-Kais and a few Shiden that were left.
That unit’s operational debut was on March
19, when Task Force 58 approached the Japanese home islands to attack Kure harbour and several
airfields in the region. More than 300 American aircraft were sent, and of those, more than
half were fighters, mostly F6F-5 Hellcats. The 343rd Kokutai mustered about 72 Shiden-Kai.
Ignoring the usual gross overclaiming by both sides, this day resulted in the Japanese losing
15 N1Ks to 14 Hellcats lost by Task Force 58. This 1 to 1 ratio was probably the best ever
achieved by Shiden-Kais, and it was a good result given the odds it was up against.
Between March and August 1945, Shiden-Kais, tasked with the defense of Japan, claimed
more than 170 aerial victories and lost more than 100 of their number in combat.
When the Japanese surrendered on August 15, only a few Shiden-Kai were still operational.
A total of 97 N1K1, 1007 N1K1-J, and 393 N1K2-J were built. Four of these are still
around today. Three are in American museums, and the last is in Japan. The Japanese one was
rescued from the bottom of the sea and rebuilt.
Many American pilots reported that the "George"
was able to fight on an even footing against their Hellcats. So, let’s compare the two aircraft
as they met over the Philippines in late 1944.
The Japanese fighter had a lower wing
loading, despite the much smaller wing area. The Hellcat was one of the largest
single-engine fighters of the conflict, but it was also a heavy beast. The time
through 360º tells us how good their continued turn performance was, and it was about two seconds
faster for the Shiden. American pilots stated that many times when closing behind a "George", the
Japanese pilots would snap-roll their aircraft and proceed to escape. This was facilitated by
the aircraft’s innovative automatic combat flaps. When it came to horizontal maneuverability,
the Japanese fighter had an advantage.
The American aircraft had a more
powerful engine, and, furthermore, the Japanese engine had reliability issues
and poor production quality due to a lack of proper materials. In addition, toward the end
of the war, the Japanese used bad quality fuel, with oil from pine tree roots added to the
mixture, ending with a quality of about 85 octane. So, the Homare engine probably produced much
less power than advertised. This might explain why there is a large difference in results from
different tests concerning the N1K1-J. That is more noticeable in the vertical speed and overall
speed values, so I decided to add a range instead of a single value for those characteristics.
The Shiden had a better power-to-weight ratio, weighing almost two tons less. It could take
anywhere between 5.5 and 7.4 minutes to reach 20,000 ft. A huge difference in values, but
all better than the Hellcat’s value of 7.7. So, it seems like it could outclimb the F6F
Hellcat, even if marginally in the worst case.
Once again, there is a wide range of values for
the Shiden’s maximum speed. These go from 362 to 408 mph, a huge difference. Several reports from
Hellcat pilots seem to hint that the Japanese fighter might have had a small advantage in speed.
Be that as it may, with such a range of values, it’s hard to reach any conclusion, so I would
say that their speed was at least comparable.
The Shiden was heavily armed with four 20 mm
cannons. It also carried two rifle-caliber machine guns that were of little consequence.
The Hellcat had six Browning M2 machine guns. There was also a less common loadout
with four of those and two 20 mm cannons. For this comparison, we’re assuming
the Hellcat with the six Brownings.
The Shiden carried 100 rounds per cannon,
compared to 400 per machine gun on the Hellcat. The Japanese fighter took 12.5 seconds to
empty those, while the Hellcat took 30, even though it had a greater rate of fire.
This was a considerable advantage for the American fighter. Its important to add that the
improved Shiden had double the amount of ammo than the version we are comparing here.
To look at how much power each gun packed, we use the tables published in "Flying Guns World
War II", probably the best book ever written on this subject. These tables combine a large number
of factors to arrive at a value for the amount of power contained in each round and each gun. Based
on this, we can see that a Type 99 20 mm cannon HE shell had about three times the destructive
power of a Browning machine gun API round. Although the cannon’s smaller rate
of fire reduced this advantage, a single Type 99 cannon packed much more
punch than a single Browning M2 machine gun.
In the end, the Shiden's weapons were
more powerful and better at dealing with hard targets like heavy bombers, but the
American fighter might have been better at dealing with lighter targets thanks to
its larger volume of fire and ammo pool.
The Shiden reached 2,000 ft higher than the
Hellcat, but it seems that the Japanese fighter’s performance worsened quickly above 20,000
ft. The Hellcat lacked a turbocharger and, as a consequence, didn’t have a stellar
performance at high altitude either.
The American fighter had an advantage in range.
The Shiden was well armoured for a Japanese fighter. It had self-sealing fuel tanks and 55 mm
(2.17 in) of armoured glass. However, the Hellcat was extremely rugged and had 212 lbs (96 kg) of
armour protecting the pilot. Very few fighters could even compare to it in this chapter.
So, based on what we covered, I feel that the Shiden was a close match to the Hellcat,
certainly much closer than the Zero-Sen it was supposed to replace. The fact that it had
a bad kill-ratio against the American fighter comes from factors beyond the aircraft itself.
If the Shiden had been operated with high-quality fuel and made with the best materials,
it might have proven to be superior.
It’s important to add two further notes. First,
the US Navy was also employing the F4U Corsair which had better overall performance than
the Hellcat. The second was that by the conflict’s end, the US already had the Hellcat’s
successor ready to roll out, the F8F Bearcat.
The Shiden-Kai proved to be one of
the best Japanese fighters of the war. It had good maneuverability, stability, and
overall performance, but was seen as hard to fly at lower speeds, and had huge problems with
its brakes and brittle landing gear. All of these flaws made it difficult to land, turning it into
an unforgiving plane for a novice pilot and so, many of the Shiden losses were due to accidents
American pilots commonly misidentified the "George" confusing it with army fighters like
the Ki-84 "Frank”. Due to this, the final overall kill-ratio for the N1K family of fighters is
unknown, but it’s most probably worse than 1 to 1, which isn't surprising as Japan was in a very
difficult situation at the end of the war. Poor quality fuel and production, a lack of
experienced pilots, and overwhelming enemy numbers all contributed to the N1K’s underperformance.
With about 1,400 Shidens produced, they were built in relatively small numbers and
entered the war when there was little that could be done to change the outcome. As
with many weapons for the axis, in the end, the Shiden is a case of too little, too late.
Was this the best fighter available to the Japanese, or do you prefer any other? Let
me know in the comments below. Thank you very much for watching, and please remember to
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