Kawasaki Ki-100

The Kawasaki Ki-100, a fighter aircraft was first used by the Imperial Japanese Army in World War II and was given the designation “Type 5 Fighter” by The Japanese Army. It was a result of an emergency measure of adapting a Ki-61-II-KAI fighter to carry a Mitsubishi radial engine thus leading to the invention of an excellent interceptor fighter, one of the best used by the Army during the entire war. The Ki-100 took its first flight on the night of 9 March 1945 and but soon suffered its first loss on 7 April 1945, when a Ki-100 flown by Master Sergeant Yasuo Hiema was shot down by a B-29.

Since starting Ki-100 showed its good qualities against the USAAF B-29 heavy bombers at high altitudes, and was equally effective against U.S. Navy carrier fighters. Although fewer Ki-100s were available but proved to be one of the most important fighters during the whole world war.

Due to the success of Ki-100, it was decided to initiate production of this aircraft, the resulting Ki-100-Ib differing only by having the cutdown rear fuselage and all-round-view canopy that had been designed for the proposed Ki-61-III. A more effective version which is to be powered by the Mitsubishi Ha-112- Ilru engine is also being planned which includes a turbocharger to improve high-altitude performance, but only three of these Ki-100-II prototypes had been built and flown by the end of the war.


Crew: 1
Engine: 2 x Mitsubishi Ha-112-II, 1125kW
Take-off weight: 3495 kg (7705 lb)
Empty weight: 2525 kg (5567 lb)
Wingspan: 12 m (39 ft 4 in)
Length: 8.82 m (28 ft 11 in)
Height: 3.75 m (12 ft 4 in)
Wing area: 20 m2 (215.28 sq ft)
Max. speed: 580 km/h (360 mph)
Cruise speed: 400 km/h (249 mph)
Ceiling: 11000 m (36100 ft)
Range w/max.fuel: 2200 km (1367 miles)
Range w/max.payload: 1400 km (870 miles)
Armament: 2 x 20mm cannons, 2 x 12.7mm machine-guns

14 thoughts on “Kawasaki Ki-100

  1. Ron

    The Type 5 (Ki 100) was compared to the unreliable Ki 61-II: “It had a much better rate of climb than the Ki-61-II and was much more maneuvrable at high altitude.”
    This is interesting since the Ki 61-II sparkles up high, potentially.
    The other comparison I ran across was that the Ki 100 Type 5 outmaneuvered any contemporary US fighter and matched the post-war F8F Bearcat!

    I know the Ki 100 lost some performance with altitude but not as sharply as other Japanese fighters.
    In mock dogfights, it beat the Ki 84 every time. With altitude advantage, it could hold down 3 Ki 84s to a draw! It had superior climbing turns. They switched pilots but still with the same results.

    In combat with P-51Ds the Ki 100s would end up down low, where the Mustang was at a disadvantage. Or even successfully diving away, it could escape.
    Some units were capable of trading losses equally even though heavily outnumbered. Attrition was very high anyway. The 57 plane 111th regiment lost almost 100 Type 5s in a few months time (150 fighters were supplied them in total).

    That Ha-112-II engine was around for along time. This means the Ki 100 could have been built long before 1945.
    It’s speed would not have been such a big handicap then. However, in context, the new 1945 A6M7 Zero was maxing out some 20 mph slower still. And this Kawasaki fighter was everything the Zero wasn’t. It was the toughest built Japanese fighter even with pilots surviving multiple B-29 ramming. It had the most armor too.
    While it’s nose cannon RoF was slowed by over half @ 400 rpm, it had more than double the range of wing cannon to compensate. The wing 12.7mm MGs had a RoF @ 900 rpm and less prone to jam than 20mm during high-g combat flexing wings.

    It was more like a US fighter than a Zero. Imagine if the huge production quantities of the Zero after it was obsolete, had been Type 5s instead! No Zero could dive 528 mph and retain high speed on pullout like the Ki 100. It could have also replaced the Ki 61 mid-war, after it lost it’s advantage and became a mechanics nightmare in the tropics.
    When the Tony had more losses on non-combat flights than losses to US pilots, the urgency should have been enough to give birth to the Ki100 then and there.
    That would have given ample time for the high altitude Ki 100-II and more.

    1. Heinkel Wulf

      Ron I believe you said the Ki 100 wasn’t just the toughest but best armoured Japanese fighter. I know all three of Japans top trio of late war fighters (Ki 84 Ki 100 N1K2) were rugged and heavily armoured as well, but how is the Kawasaki different in this regard? Was the earlier Ki 61 as tough as these other two as well as being as tough as the Ki100, or did the later ki 61 2 and ki 100 possess a stronger structure and heavier armour? How did the durability of all three compare, and what about the ruggedness of the N1K1 vs N1K2? Was the Ki 100’s speed on par with Japans other two late war types when tested on high octane? I dont see how it wouldnt be. Also I’ve heard some claim these fighters somehow weren’t as tough as their american counterparts despite TAI giving Japanese armour and fuel tank protection used late war a clean bill of health. I find it hard to believe these aircraft were somehow less tough than their american rivals despite the weight difference. For example, a T 55 tank may be lighter than a Tiger 1 but is arguably more heavily armoured despite the weight difference. and both using steel armour. Doesn’t the same possibility apply here? I can’t help but suspect there is a subtle level of subconscious racism in people from forums UBI for example assuming the Japanese late war types were somehow inferior to the American ones, when the facts clearly contradict this. Curious as to your thoughts Ron.

      1. Heinkel Wulf

        Also, when you mentioned the Ki 100s ability to ram multiple times with the pilots surviving, did you mean in the same sortie, or the fact that it was tough enough for the pilot to survive most of the time to switch to another Ki 100 to do it again another day?

      2. Ron

        The Kawasaki fighters started with pilot armor and progressively increased the thickness over time.
        The Ki 100 had 16mm in places as did the Ki 61-II.
        The dive speed is partly a result of robust build, pulling out at 528 mph wasn’t a problem. The other fighters you mentioned were well shy of that- – even the Reppu. The Ki 100 retained speed on pullout very well, so calling it a 360 mph fighter can be misleading. I know Japanese fighter speed is a subject of controversy since they recorded speed at military power and not boosted WEP speed like in the West. But what do I know?
        For example the Zero 21 is published most capable of 331 mph at around 14,000′. But Sakai said with the proper settings for boost, it went 345 mph. But that wouldn’t have been published had he not said it.
        The captured Zero 21 was not properly set for that speed due to US ignorance of the settings the aces used. Forgivable though. It’s like the bogus roll rate of the captured Fw 190A vs the F4U. The US had the control cables adjusted wrong. Thus the Corsair matched the roll of the Fw 190A.
        In Germany these results would vary considerably.

        On the firepower, the Army 30mm Ho-155 cannon as installed on the Ki 61 was a problem. It had nil accuracy and cracked the wingspar. It was withheld from combat. I don’t know if the Ki 84 so armed, saw combat. I know the Navy 30mm cannon experiment with the Zero didn’t catch on. In the case of the Ki 44, it had stubby wings and they were strengthened. True, the 40mm Ho-301 cannons had no recoil. But I tend to believe the Russian account of capturing Ki 44s with 37mm Ho-203 cannons. I don’t know the affect on the wing, but the Ki 44 was the most accurate gun platform. A Raiden prototype with 30mm Navy cannons did knock down a B-29 with one head-on salvo. A few were subsequently armed with 2x30mm Type 5 cannons but I don’t know the combat results. Obviously, this heavier cannon would impact the Raidens dogfighting prowess to survive the US fighter escort, which was already problematic that high.
        The A7M2 Reppu flew with the same armament as the A6M8 but was designed to pack more firepower. The subsequent models never flew, but planned to had not only 4x20mm cannons but 4x30mm Type 5 wing-cannons and twin dorsal 30mm cannons for good measure on the long-nose A7M3-J! The Reppu was a big strong fighter. The A8M2 Rifuku was the same but dropped the dorsal twins and up-engined from the Ha-43 to the Ha-44 of 2400 hp. 1946 was the target.
        I like the 400 r/m high velocity 37mm Ho-204 cannon. I think the Ki 46 Dinah should have had it mounted in the nose like the Ki 102 Randy instead of the dorsal angle. This cannon was the fastest 37mm of WW2.

        As far as racism goes. It was a different world then. Can we judge by todays views? Having said that, it still bugs me too. Of course all sides were racist

        I’m not infallible. I’ve posted things I’ve had to amend.

        1. Heinkel Wulf

          Danke Ron. 🙂 Its always refreshing to speak with a second world war aviation enthusiast who isn’t blinded by national bias. As for the Ki-100, I can see why so many regard it as the finest of Japan’s fighters to see combat. As you stated, even when compared to the Reppu it was quite a beast. Fast, with phenomenal maneuverability, very good high altitude performance, a tough as iron airframe, long range hard hitting armament, and insane dive speed and pullout retention. All these things combined with the three things Japan’s other late war superprops such as the Hayate and Shiden were a bit lacking it: reliability, ease of serviceability, and ease of handling, made it all but perfect for the conditions the Japanese air forces found themselves in during 1945. With materials and quality pilots running scarce, a top tier machine that could be repaired and loaded out quickly, with a dependable high performance engine, and handling that could allow for even green pilots fresh out of flight school to have a fighting chance, the Ki-100 was about the best there was for the job. Japan’s Douglas Bader Yohei Hinoki (also known as the “Master Falcon” I believe) had nothing but postitive things to say about it, and achieved some quite impressive feats in it against Mustangs over Okinawa I believe. It’s nothing short of phenomenal that this aircraft was not only able to match the post war American Bearcat, but hold down not one, not two, but THREE Hayate’s to a draw even when pilots were switched. To think it could of come well before 1945 is quite remarkable as well. The Kinsei and Hien were both available, but I suppose nobody thought to mate the two together until the bombing of the factory/factory’s producing inline engines was destroyed. Again, I appreciate your taking the time to read through the huge bricks of text I sent to answer my questions Ron. You may not be infallible, but you’re easily one of the most knowledgeable individuals I’ve seen speak on the topic, and it was a pleasure conversing with you. ^_^

  2. Heinkel Wulf

    One last thing Ron. I read somewhere that there was a bomber destroying “ic” variant of the Ki 100, with the same 2 20mm ho5 and 2 30mm ho155 cannons as the Ki 84 ic. Is this true, or just a rumor? If its just a rumor, than were any other Ki 100s planned or built with an all cannon gun mount, or were they all fitted with the standard 2 50 cal and 2 20mm cannon load out? This seems like an already solid gun fitting, and out of curiosity was wondering how effective it would be against heavily armoured p47s and the large b29s. That’s all I’ll bother you with. Thanks.

    1. Heinkel Wulf

      Ok my bad ROn, just one more thing. I would also like to know your thoughts as to the comparative features of the A7M Reppu as well. Sorry, I’ve seen you on other sites like Avistar, (I think?) and your about the most well read and unbiased person on the topic I’ve yet seen. You’ll have to forgive me, but I simply can’t resist the chance to pick your brain here. XD

      1. Heinkel Wulf

        I guess to be specific Ron, I meant the features I brought up of the aircraft I mentioned, but compared with the Reppu as well. Thanks. Also, I totally misspelled Aviastar. My bad. XP

  3. Heinkel Wulf

    Correction, how effective was the stock weapons package, as I know they shot down B-29’s and P-47’s on a fairly regular basis. Seems to pack an adiquate punch to me, especially with the 20 mil’s being concentrated in the nose, with the 12.7’s in the wings being less likely to jam from what you’ve pointed out. Was just curious as to your thoughts.

    1. ron

      With the dwindling supply of rare metals and degrading quality standard toward the end, the IJA 20mm Ho-5 M/V suffered to the point where range went from 900m to 600m. The rate of fire was still top-notch in the wings though at 850 r/m average. (425 cowl, since they were Browning derived).
      Ki 84-Ib 4x20mm Ho-5 WoF: 4.040Kg/s for 10.6 sec (Ki 61-IIb KAI for 8.5 sec) Thereafter, they only 2 nose-cannons firing for around 10 sec. more.
      The IJN 20mm Type 99-II was relatively unaffected somehow.
      Of course it was also the slowest 20mm at around 500 r/m depending on model.
      The 20mm Model 5 of the Type 99-II, was much faster at 680-750 r/m but it is unclear if it saw much action since it was produced from May 1945 on. It was slated to be on the A7M3 Reppu, 6 of them in the wings! I would’ve liked to see The P-47N square off with the A7M3-J which had 6x30mm Type 5 cannons, 2 of them were dorsal. Those were more powerful than the 30mm Ho-155 of the Army, but slower.
      If they did see action, what fighter was most likely armed with them? I don’t know. I wish it was on the contemporary A6M7 Zero. But that makes too much sense which did not often prevail, considering the climate of 1945 Japan.

      1. ron

        I meant the 20mm Type 99-II/5 for the Zero A6M7 oviously. Not the 30mm.

  4. ron

    I believe the J2M5a had 4x20mm fast Type 99-II Mk 5 cannons in the wings (the Reppu A7M3 was planned to pack 6 of these in the wings). This cannon with modified buffer, had a RoF up to 750 r/m like the late-war RAF (Tempest) 20mm Hispano Mk V. These were much more reliable than the U.S. 20mm M2 Hispano
    (P-38L) or even the post-war M3 Hispano cannons (F8F).

    But pilots didn’t like the J2M5 because the turbosupercharger made the high altitude engine, failure prone. Tungsten was rare in 1945 Japan. In the case of the high altitude Ki 100-II with a similar engine, things may have worked out better.
    The Kawasaki Ki 64 and Ki 119 fighter designs did have 4x20mm Ho-5 cannons.
    The Ki 84-Ic with 2×20 and 2x30mm Ho-155-II cannons had about 6kg/s WoF by my estimate.

  5. Heinkel Wulf

    @Ron What are your thoughts on Nakajima’s Ki-87 as compared to other Late war Japanese fighters (specifically the Ki-100, but also the A7M, Ki-84, and N1k) and America’s P-47 and Mustang? I know it was designed from the start to be a high altitude counter to the T-bolt from the start, and seems remarkably comparable in terms of weight and performance to at least the D model, but I’m not sure about the P-47M and N models. I’m most curious about the latter, because imho, the Jug was America’s finest all round fighter of the war, save for the Corsair, which I’ve heard many a story about how high performing, but tricky a handler it was (seems like the most direct American analogue to the N1k) and the Hellcat which seems to have had the best balance of performance/handling for US navy fighters of the day. If I was in the USAAF or US Navy at the time, I’d probably pick the T-bolt or Hellcat as my preferred mounts, while the Ki-100 or A7M would be my pick if I were Japanese.

  6. Heinkel Wulf

    Also, what are your thoughts on Boeings XF8B as compared to the previously mentioned late war Japanese fighters? Now that I think of it, from what I’ve read, I think that would be my US fighter of choice during the war. It’s obviously going to take up quite a good bit of space (biggest/heaviest single piston engine fighter of all time as far as I’m aware) on a carrier, but with the range, performance, armament, and payload, I think it would’ve been a huge winner if Boeing had gone ahead with production.


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