Nakajima B5N2 Kate

One of Japan’s modern types that shook the Western World at the start of the Pacific War.

Let’s take a look at a particularly significant example.

There was arguably nothing shocking about the B5N. As a Naval bomber it could even be considered obsolescent at the start of the Pacific War. Except, it was faster and more modern than either the Douglass TBD Devastator or Fairey Swordfish. That combined with a much better torpedo that could be dropped from higher and faster than allied types, and had significantly better performance in the water, meant the Kate delivered massive damage to allied shipping in the opening moves of the War. Particularly in the early carrier battles (Coral Sea, Midway; even as late as Eastern Solomons and Santa Cruz) this led to the anti-torpedo fighter screen being stationed too low to make a really effective intercept. This last is very important, my quick research failed to turn up the exact numbers, but the Kate would fly en route at several thousand feet, then descend for a torpedo drop much later and much faster than comparable allied aircraft did. USN fighter directors would figure this out and adjust accordingly, but much later than one might expect. From 1943 US carrier forces would become massively dangerous targets for any attack aircraft, but through 1942 they were still learning the game.

The B5N entered service in 1937 and was used in the Sino-Japanese War. It had a crew of three; Pilot, Observer/Navigator/Bombardier, and Radio Operator/Gunner. Unlike western navies, the Observer (middle seat) was usually the aircraft commander. Although generally identified as a torpedo bomber it could also carry a single armor piercing 800 kg bomb, two 250 kg bombs, or six 60 kg bombs. The improved B5N2 entered service in 1939 and had replaced the B5N1 in all front line units by the start of the War.

The two 250 kg bombs were carried off-center and staggered.

On June 4, 1942, this aircraft was flown on two missions by Lt Joichi Tomonaga. Lt Tomonaga was a veteran of the China War, but these were his first missions against the US. He was the air group commander on the IJN Hiryu, flagship of the second carrier division. The first mission that morning was the air strike, the intended complete neutralization, of Midway Island. Cmdr Fuchida, the Kido Butai’s usual strike leader (and Akagi air group commander), was out of action that morning while recovering from an appendectomy. So it fell on Lt Tomonaga to be strike leader. The fleet air commander, Minoru Genda, felt it would be good to get Lt Tomonaga some command and combat experience against the Americans in this slightly less critical mission (compared to a major fleet action).
All Kates would have launched from near the rear of the flight deck, fully loaded with bombs and fuel it carried significantly more weight than either the A6M Zeroes of D3A Vals which all had roughly equal horsepower. In short, the plane was a bit of a pig getting off the deck (according to Parshall and Tully in Shattered Sword).
110 aircraft (36 Zeroes, 36 Vals, 38 Kates) composed the morning strike on Midway. The Kates carried two 250 kg bombs for land attack. They were intercepted by Marine fighters, a mix of Wildcats and Buffaloes, that were pushed aside with little loss. Anti-aircraft fire over Midway was moderate, actually heavy for that point in the War. Enough that when Tomonaga radioed the fleet at 0730 “there is need for a second attack” he had lost a number of aircraft and many of those remaining were damaged.

B5N Kate in flight [public domain]
Japanese carrier air group for the first year of the War consisted of the B5N Kate, A6M Zero (Zeke), and D3A Val. All three aircraft here are from the Hiryu. The Zeke and Val are in Pearl Harbor markings, which is why they have two blue stripes and a “BII-” tail code. At some point before the Battle of Midway, Admiral Yamaguchi switched his flag for Carrier Division 2 from the Soryu to the Hiryu. This led to identifying markings on the two ships’ air groups to be switched as well. I don’t know the reason for this, beyond observing the Hiryu was three years newer and slightly bigger.

The Midway strike aircraft returned to the fleet around 0815, which is part of the whole cascade of events that fell on the Japanese this day. Admiral Nagumo, in charge of the Kido Butai, needed to land his strike group, fuel and arm the next wave of aircraft to attack Midway (or the American fleet as events unfolded) all while under attack from planes from Midway and the US carriers. The uncertainty of if enemy aircraft carriers were present or not added to the problem. I’m sure most readers have read the story of if the bombers were to carry bombs or torpedoes; for the B5N this is particularly a big deal as it meant changing out all the brackets for the ordnance, torpedoes and bombs do not use the same size mounts. A detail that often gets overlooked too is that the Kido Butai’s entire fighter strength was aloft at this time, so any attack would be delayed while a number of fighters were landed and serviced as well.
We know catastrophe hit the Japanese from 1010 to 1020 that morning. Essentially the laundry list of things to do was too much and they ran out of time. With 3 out 4 aircraft carriers in flames that left Hiryu alone.
The Japanese could still demonstrate remarkable efficiency, the first counter attack on the American carriers of 18 Vals and 6 Zeroes was launched from 1054 to 1058. This force, led by the Hiryu’s dive bomber squadron commander Lt Kobayashi was able to follow Yorktown Dauntlesses that had just blasted their own fleet right back to their own ship. Kobayashi’s attack did succeed in damaging Yorktown, but at the cost of 14 dive bombers and all six fighters (technically 1 dive bomber and 3 fighters were only “damaged”, but the distinction proved irrelevant). The attackers thought the damage done was serious.
The next strike would be Lt Tomonaga’s second of the day. During the morning attack on Midway his B5N had suffered damage to the left main fuel tank. Repairs were attempted during servicing but failed. So the Lt knew this was likely a one-way trip. Other pilots in the squadron offered to fly the damaged plane but the offers were declined. The force Lt Tomonaga led was ten B5Ns and six zeroes. One hour after the dive bomber attack they found an apparently undamaged aircraft carrier and attacked. This was Yorktown again, under way and not nearly as badly damaged as believed. But the Kates scored two torpedo hits that caused significant damage. 5 Kates and 2 more Zeroes were lost (with another 2 Kates and 3 Zeroes damaged beyond repair; the Japanese paid a heavy price for their lightly built aircraft). Tomonaga was among those who didn’t survive. He was shot down by Yorktown’s fighter squadron commander and leading ace John Thach just as he dropped his torpedo. The torpedo missed.
This left Hiryu with 5 Kates, 5 Vals and 10 Zeros for one more strike. Quite a change from over 200 aircraft available that morning. But Dauntlesses from the Enterprise located and destroyed the Hiryu before such a mission could be flown.

Two torpedo bombers that led attacks on June 4, 1942. Both were lost with their crews.

This is the Hasegawa kit. It was a special Midway boxing that could be marked as any Kido Butai B5N in use on June 4, but the box art features this plane and I never considered building any other. The kit has armament for either the morning’s bombing mission or the fatal torpedo attack. I chose the bombs because I have a couple more Hasegawa Kates, but I don’t think I’ll have another excuse to build one with this load.

June 4, 1942 also marked the combat debut of Grumman’s big new TBF Avenger. A much bigger and more powerful aircraft, it represented a new generation of US combat aircraft that the Japanese would never quite equal.

About atcDave

I'm 5o-something years old and live in Ypsilanti, Michigan. I'm happily married to Jodie. I was an air traffic controller for 33 years and recently retired; grew up in the Chicago area, and am still a fanatic for pizza and the Chicago Bears. My main interest is military history, and my related hobbies include scale model building and strategy games.
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15 Responses to Nakajima B5N2 Kate

  1. Pierre Lagacé says:

    Reblogged this on My Forgotten Hobby IV.

  2. Pierre Lagacé says:

    Is it a new build Dave?

  3. Kevin Kennedy says:

    Always informative, a great read… as well as another job well done on the build… Congrats, Amigo!

    I am very interested in the IJN, and very much enjoy expanding my knowledge of the Kido Butai, with particular emphasis on carriers Akagi and Kaga, especially Kaga!! I do not know exactly why, but IJN Kaga captures my imagination most, and was elated to discover, that a few years ago, she had finally been found by philanthropist, (the late) Paul Allen, and the Research Vessel, Petrel. I remember a couple of decades ago, Bob Ballard, expidition leader for Titanic and Bismarck, had searched for Kaga, but was unsuccessful. Now, I believe, almost all the carriers involved in the Battle of Midway, have been located.

    Anyways, earlier this year, Artist Ron Cole released a very limited art print of a ‘Kate’, flown from IJN Kaga, by F1c Shuzo Kitahara, for the 7 December 1941 Pearl Harbor attack… attached to the print, is a small fragment of the very ‘Kate’ depicted in the print. The (rare) fragment was part of a (bit) larger piece that had been removed from the vertical stabilizer, which had been cut, and saved, all those decades ago… an historical treasure to be sure! And, of course, I had to obtain one of the prints for my collection.

    Thank you, again, for sharing the fantastic build, and for the effort to keep history, (those who lived and experienced it), alive. All the best!

    • atcDave says:

      Wow Kevin, that’s really cool. No doubt the Japanese carriers have a unique and interesting look to them. And they caused enormous damage in a short time. Even so, in the end they seem to have been glass cannons!

  4. Pierre Lagacé says:

    Hasegawa will be releasing in December a limited edition of the Kate, the Zero and the Val from the Akagi with Pearl Harbor markings.

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