Pimp my Zero!

Just a fantasy wish list about gearing up the A6M5 Zero, for late-war fights.

1) Kinsei 62 Engine

The Zero really needed an engine upgrade after two years. 1100 hp just wasn’t going to do it, and you can’t squeeze any more from the old Sakae engine. The Zero was very good at pulling its nose up, and was very light so that the initial climb seemed impressive, but the speed soon levelled off. Allied planes could run going up (eventually) or diving down.

It should have had the Kinsei 62 engine (1550 hp) for the A6M5 upgrade, like the engineers wanted.

2) Aileron servo tabs

Very important to improve the roll rate at high speeds. The Zero’s ailerons became very stiff at 300mph, barely moveable. Servo tabs increase leverage and will make them usable. Rolling well makes the plane’s movements less predictable and pilots can respond more quickly.

The Zero actually had them in the beginning, but pilots went wild and overstressed the wings doing high-speed roll and tight turns, risking break-up in mid-air. So Horikoshi removed them to get the pilots to slow down.

Put them back on. Late-war aces don’t do steep turns, they fly fast, barrel-roll and slide a lot.

3) IJAAF Ho-5 cannon

The Navy’s Type 99-1 autocannons had poor firing rate and muzzle velocity. You had to be close in to hit anything. The Type 99-2 had higher muzzle velocity but worse firing rate, you can shoot further out but tend to miss. You could install a bunch of them and compensate for the firing rate, if the plane could take it, like the Shiden-Kai and the Raiden. But the Zero is just too small. There’s just no room.

Meanwhile the Imperial Japanese Army Air Force had a good autocannon of their own, the Ho-5. Muzzle velocity like a Type 99-2, and firing rate like a machine gun.

A couple of hot Ho-5 on a Zero would be just nice. You turn your plane and rip your target at a shocking distance, just when he thinks he’s beyond range.

4) A Working Radio

Team tactics are hard to do without a working radio. Actually there was nothing wrong with the radio itself. The engine’s ignition system was interfering with it, every time a spark plug fired. Somehow it took them almost three years to realize it and shield the radio.


So… increased engine power, tabs for better high-speed roll, Army autocannons, and a shielded radio. Not too much ask for, Shirley?

Aww, forget the Zero. Put four hot Ho-5 in a Shiden-Kai please.


Japanese Air Force Cannons

The Imperial Japanese Navy and Army Air Forces took two different approaches when they decided to equip their aircraft with 20mm autocannons.

The Navy tested some Oerlikon 20mm autocannons, liked it and started local production of two Oerlikon-types, which they called Type 99-1 and Type 99-2. They’re really local copies of the Oerlikon FF and and the larger FFL. The Oerlikons (and therefore both Type 99’s) had a rather low rate of fire. Type 99-1 had low muzzle velocity in addition.

The A6M Zero was equipped with wing-mounted Type 99-1, muzzles flush with the leading edges. Later versions of the fighter were equipped with the longer Type 99-2 with muzzles portruding from the wing edges. Zero pilots generally didn’t like firing the earlier cannons, they were slow-firing and only good at very close range on slow-moving targets. Pilots relied more on their cowl machine guns. Instead of blasting their foes with a few cannon shots, pilots like Saburo Sakai would hang on their target’s tail and pour their two machine guns on it. And sometimes the target would just keep on flying.

The Army got in a bit later and with an approach I found very interesting. They started out with the Ho-103 12.7mm machine gun, a local version of the American Browning 1921 .50 caliber that Americans nickname the “Ma Deuce”, modified to use shorter cartridges to improve rate of fire.

Then they simply scaled up all the parts, loaded it with explosive shells, and got a very decent autocannon indeed, the Ho-5 , with faster muzzle velocity and higher rate of fire than the Navy’s Oerlikon derivatives. Some have called it the best autocannon of WW2, and even some Americans wonder why their own forces didn’t simply upsize their beloved “Ma Deuce” to fire shells. The Ho-5 was only slightly heavier than the 50 cal Browning, and packed a bigger punch per weight.

(The Americans really did consider cannon-arming their single-engine fighters, as can be seen in the P-39 Airacobra. They tried producing Hispano-Suiza cannons but their contractors botched it.)

The Ho-5 went to equip the Ki-44 Shoki, Ki-84 Hayate and Ki-45 Toryu, and generally, the Army pilots fired their cannon more often than their Navy counterparts.

If the Navy’s aircraft cannons were so inferior, why didn’t they switch to Army gear? Well, there was a fierce rivalry between the two arms. They would even design aircraft that shared no common spare parts, and use mutually incompatible ammunition.

And then there was the cartel of retired-Admirals-turned-contractors supplying the Type-99’s, they were really tight with the Navy and elbowed out any competition, let alone allow Army equipment into the Navy system.

The Navy worked around the Type 99-2’s low rate of fire by putting more of them on their planes when possible: the Kawanishi N1K Shiden and Shiden Kai carried four of them, as did the Mitsubishi J2M Raiden. Late-war A6M5 Zeros complemented their two wing cannons with two wing-mounted heavy machine guns. They would have mounted four cannons in the Zero if only there had been room, and the weight of doubled armament compromised the Zero’s chief advantage: agility.

Late war Japanese Army fighters made do with two Ho-5. It was enough.

Zeros equipped with Ho-5 would have remained useful late-war, retaining its agility while delivering a good punch from longer range. When your enemies are faster than you, you need to be able to hit them even as they pull further away and make the kill before they escape. Having a good firing rate helps to hit the target as well.

It was a strange compliment to the Browning Ma Deuce, that an upsized version of it firing shells became a favourite weapon of the Imperial Japanese Army Air Force.

Some data:

Army Ho-5:

Caliber: 20 mm (0.8 in)
Ammunition: 20 x 94 (84.5 g)
Weight: 35 kg (77 lb)
Rate of fire: 450-600 rounds/min (some sources put it as high as 950 )
Muzzle velocity: 750 m/s (2,460 ft/s)

Navy Type 99:

799px-Navy Type 99-1 & 99-2


Type 99-1:
Caliber: 20 mm
Ammunition: 20x72RB
Length: 133 cm (53 in)
Weight: 23 kg (51 lb)
Rate of fire: 520 rounds/min
Muzzle velocity: 600 m/s (1970 ft/s)

Type 99-2:
Caliber: 20 mm
Ammunition: 20x101RB
Length: 189 cm (74 in)
Weight: 34 kg (75 lb)
Rate of fire: 480 rounds/min
Muzzle velocity: 750 m/s (2460 ft/s)

Hack jobs of the skies

I have a soft spot for “hack job” WW2 fighters. Usually it involved replacing a problematic inline engine with a radial (eg La-5 and Ki-100), although in some cases it went the other way(Fw-190 D); resulting in a plane that had a fat nose, or an elongated one. Sometimes as in the Nakajima K-44, it was the result of an unusual requirement leading to an unusual design. Sometimes they just hacked up a plane designed for one role and got a better one for an entirely different niche (eg. Kawanishi Shiden).

Lavochkin La-5
Originally it was the LaGG-3, which had been designed for a powerful inline engine. The LaGG-3 was supposed to address an aluminium shortage by building large parts with phenol-impregnated wood, which also made it heavy. However that engine was found to be unreliable, so they substituted it with a weaker inline, and got an underpowered overweight fighter that moved like a slug. Even Stalin started to notice how awful it was and started breathing down Lavochkin’s collective necks.

Nervously (who wouldn’t be nervous with Stalin watching?) Lavochkin fitted a rather large radial engine, and got a surprisingly decent fighter with a wide cowl for the radial and narrow body originally designed for the inline, which was renamed the La-5 (no G because Godunov was kicked out). When aluminium became more available they replaced the wooden parts with metal and cleaned up the aerodynamics a bit and got the even better La-7.


Kawasaki Ki-100
It started as the Ki-61 Hien, Japan’s one and only inline-powered fighter. The engine was a copy of the German Daimler-Benz that powered the Bf-109, making the plane look like an Italian design (eg. Macchi C.202 Folgore), thus the Allied codename “Tony”.

High powered liquid-cooled inlines were harder to mass-produce. Kawasaki never really solved the problem of quality control. Ki-61 fighters spent a lot of time grounded at their bases due to engine problems, while in Japan there were many more airframes gathering dust in warehouses due to bad engines being rejected.

Then Kawasaki’s engine factory was bombed in 1945, halting all production of that problematic inline. They fitted a Mitsubishi Kinsei radial on the airframes and found a surprisingly good fighter, one that Japanese Army aces said outperformed their Nakajima Hayate. They called it the Type 5 Fighter (Go-Shiki-Sen). Like the La-5, it had a large radial-engine cowl and narrow inline-engine body. It appeared so late that the Japanese and the Allies never gave it a proper codename.

Why didn’t they do this sooner like Lavochkin? Maybe if the Emperor ordered them to or else commit seppuku…

Focke-Wulf Fw-190 D
The highly successful Fw-190 A was a radial engined fighter with one problem: poor high altitude performance. Its powerful BMW engine had been intended for transports and airliners! No one had expected it to power a fighter at high altitude. The engine had been chosen because the more obvious high-altitude inline engines had been snapped up by Messerschmitt, Heinkel, Henschel and Junkers. Even the radial originally picked by Focke-Wulf had been snatched. Only the airliner engine was left.

That made the Fw-190A a sort of hack job already, but at least the plane was designed to accommodate a radial engine of that size. It was a tough bird that shrugged off ground fire and absorb much damage because there were no leaky radiators to worry about.

But high-altitude work was left to the Bf-109, which by 1944 needed a bit more help.

So Kurt Tank of Focke-Wulf put a huge Jumo inline bomber engine on the Fw-190, and stretched the fighter’s body a little for balance, resulting in the gangly and awkward-looking long-nosed Fw-190 D, the “Dora”. It was supposed to be a stopgap until he finished testing the more advanced Ta-152, but the Luftwaffe pilots couldn’t get enough of it, they loved it! A remarkably successful hack-job.

The Ta-152 looked very similar to the Fw-190D, using the same engine and similar fuselage. The difference was in the internal structure which was strengthened to accommodate the increased weight and power and to rebalance the fighter. The Dora was pretty much a fast and high climbing straight-line fighter, the Ta-152 was supposed to be more balanced and able to manoeuvre better. Only a few got into the air before the war ended.


Nakajima Ki-44 Shoki
This is not quite a hack-job: the fighter was designed that way from the beginning. But it deserves a mention anyway. When Nakajima was told to design a bomber-interceptor with a furious rate of climb and speed, the only way they could do it at the time was to fit the biggest radial engine they had on as small a body that could still hold it.

I think it made the designers at Nakajima wince. Their other designs were beautiful.

But it was a reasonably successful design, having a performance remarkable for 1941-42 in climb and top speed that matched the later J2M Raiden (1945).

Nakajima had to stop building them because they had to retool their factories to produce their new fighter, the Ki-84 Hayate. There simply weren’t enough factories to produce all the types of Nakajima planes, although they kept cranking out Zeros until the end.

Yes, Nakajima built Zeros under licence and eventually built more than Mitsubishi did.

Why not stop Zero production and keep building Shokis and Hayates?

Stop Zero production? Kinjiru! (Forbidden!)

Kawanishi N1K1-J Shiden
This is probably the most remarkable hack-job of them all. It was originally the N1K1 Kyofu, a sea-plane with floats under the fuselage and wings. When the Navy decided not to buy any more than a dozen, Kawanishi modified the plane into a land-based fighter by removing the floats, and installing retractable landing gear.

They replaced the engine: the large Mitsubishi Kasei was replaced with the more powerful Nakajima Homare. Now there was no more room for the cowl-mounted machine guns but the holes were left there anyway, it was welcome ventilation in the tropics. The original round cowl now sprouted oil-cooler intakes above and below the nose.

They put on extra large propellers to take advantage of the more powerful engine, but that meant they had to make the landing gear taller by telescoping it out for landing.

Oh, and high velocity cannons. There was already room for a pair in the wings in the Kyofu, so they added another pair in pods under the wings. They called the new plane the Shiden “Purple Lightning”, and added “J” at the end of N1K1 to signify the change from seaplane to land-based fighter.

It was an awful looking plane.

The Navy was lukewarm about it, they were waiting for Mitsubishi to finish the Reppu fighter which was supposed to succeed the Zero. Meanwhile the Zero had its wings shortened for speed and roll and had installed high velocity cannons to shoot at longer range instead of knife-fighting distance of the earlier models.

Mitsubishi never finished the Reppu, and the Zero was hacked out of the sky by newer Allied planes and tactics. Suddenly the Shiden was in demand. It was a fast and nimble flying tank. Japanese planes were notoriously fragile, but the Shiden could take hits and still fly; it turned like it had a turret; and with four high velocity cannons it could shoot like a tank. It was also fast and did not suffer the lousy high-speed handling of other Japanese planes.

The 1945 model N1K2 Shiden-Kai (Improved Purple Lightning) reduced the number of parts, improved the aerodynamics and put the extra cannon in the wings. I suspect they also wanted it to look prettier; the mongrel N1K1 model must have made Kawanishi’s designers cringe, it was an effective but awkward-looking plane.

Remarkably, Kawanishi was and still is a company absolutely specializing in seaplanes, not fighters. Everything else it ever built for the Japanese Navy were seaplanes, seaplanes, seaplanes, flying boats, amphibious planes, flying boats and more seaplanes. A land fighter by Kawanishi? Unglaublich! as the Germans say.

Piloting a Zero

I’ve been looking at the Mitsubishi A6M Zero fighter recently. Specifically, ways of flying the plane that allows the pilot to survive against late-war Allied aircraft and score some kills. So I visited some online forums for games such as War Thunder, Il-2 Sturmovik, Aces High and Warbirds Online.

There appears to be two schools of thought. One school advocates keeping the Zero slow and low which is where the fighter does best, turning very tight. One flyer in War Thunder insists on vertical loops. Another never goes above 170mph and using an odd combo of rudder, elevator and aileron to corkscrew: in other words, he and other players have rediscovered the old Hineri-komi manoeuvre, which was actually taught in Japanese fighter schools. In the hineri-komi, the plane banks a bit then uses the rudder to slide sideways, in the direction of the downward wing. It is strictly a low-speed manoeuvre, most often performed when the enemy is following you up  and slowing down as well. One flyer in Aces High never goes above 120 mph, turning the plane on a dime.

I found this depiction of the hineri-komi at a War Thunder forum, where both low-speed and high speed tactics were advocated for the Zero:


The “hineri-komi” manoeuvre in an overhead loop. At (5)  the Zero is turning sideways using the rudder.


The second school advises keeping the Zero fast. Well, fast for a Zero, up to maybe 250mph. And using it as what one flyer in the War Thunder forum calls “micro boom-and-zoom”, using energy tactics over short distances.  Get close to score hits. The Zero’s strengths, other than turning, are high initial acceleration and sharp climb angle. While prolonged dives are bad, you *can* dive a Zero for short sprints. When not shooting, pick up altitude and potential energy so you can pounce downwards.

Bob the Zero up and down, as needed. Western planes like to shallow climb over long distances, Zeros can climb steeply to gain potential energy. Western planes build up heavy speed, shallow diving over long stretches; the Zero (A6M3 and A6M5 models) has better initial dive acceleration at short stretch with full throttle, although the final speed is low.  Just remember to ease the throttle if diving for long, otherwise the controls jam due to the forces exerted on the control surfaces at high speed.

Turning hard with flaps spills energy by air resistance; better to do a small high yo-yo (short climb and turn), slowing down by climbing but picking speed up again coming down. High yo-yo is a maneuver devised for planes with poor turning; I find it ironic that some Zero flyers use it. Don’t turn 270 degrees, you get too slow; if you can’t nail him turning 45 degrees, let him go. One surviving Zero ace described his fighting over Okinawa in 1945 as consisting of high speed barrel rolls and violent slidesand avoiding hineri-komi turns altogether since it robbed his fighter of speed. I am still not sure what he means by sliding.

Scare the opponent by pinging with machine guns, make him turn and lose speed, then throttle up and dash in, turning hard to aim the guns a bit ahead of him so the bullets arrive at the right moment, walking the shot from nose to tail, quite possibly killing the pilot. If he’s broadside to you and close, let rip with the cannons! Don’t chase a diving enemy too long, stay up and eventually he’ll have to come back up, climbing slowly: the perfect time to pounce.

I like the idea. It’s like fighting with a short sword, quick and lethal once you get close.

Last of all, the late war A6M5 has strengthened wing skin and shorter wings, improving its dive speed to 400mph. This suggests that a high speed slash and run attack is possible if the Zero starts at higher altitude. Unfortunately the fighter’s handling at high speed is famously bad, especially the aileron roll above 300mph, so I am not sure.

The Power Zero

The Supermarine Spitfire, the Messerschmitt Bf-109, and the Mitsubishi A6M Zero, were contemporary WW2 fighters, introduced roughly around the same period. All three enjoyed successes at their early careers, but while the Spitfire and Bf-109 remained competitive throughout the war, the A6M was left behind and was unable to compete with later Allied aircraft in the Pacific.

The lag in development led to appalling losses after the Allies abandoned low-speed combat in favour of high speed attacks. The Zero was unable to run to pursue, or to escape. Initially the kill:loss ratio was 12:1, that now was reversed!

It is untrue to say that the A6M Zero did not undergo any further development. The war had begun with the A6M2. The A6M3 shortened the wings by removing the folding wingtips and made the engine cowl smaller and more aerodynamic, and improved the Sakae 21 engine by adding a two-stage supercharger for better performance at higher altitude. These modifications improved the fighter’s ability to roll and dive and increased the maximum speed from 313 to 330 mph, without replacing the engine.

The next model, the A6M5 gave the engine individual exhaust stacks that provided extra thrust, and thicker wing skinning to allow faster diving speed without tearing the wing, increasing the speed to 350mph (diving speed now exceeded 450mph), but otherwise it simply formalized the ad-hoc modifications of the A6M3.

The improvement in performance between A6M2 and A6M3 were significant, while the A6m5 model was a more incremental improvement.

Unfortunately for the Imperial Japanese Navy Air Force, the newer Allied aircraft far outpaced the A6M5 in late 1943. An over-emphasis on low-speed turning combat and range had led to neglect in protection and engine power, and above all, high-speed maneuvers.

Could the Zero have been modified further to keep it at least competitive?

Tracing the further development of its contemporaries, the Spitfire and the Bf-109, we find that:

  1. Engine power for British and German fighters kept increasing. Engine development continued as the Rolls-Royce Merlin and Daimler Benz DB-601/605 were tweaked to higher power, exceeding 1500hp and eventually 2000hp. Power increased in leaps and bounds for the Bf-109: while it had been originally designed around a 700hp engine with its high performance gained from exceptional aerodynamics, the late war Bf-109K had a Daimler-Benz DB-605 engine roaring away at 2000hp.
  2. Both aircraft began the war emphasizing low speed turning combat, just like the A6M. Despite having top speed of over 300 mph, most early war turning dogfights took place at only 150-200 mph. The Spitfire’s large elliptical wings reduced the tendency to stall when turning steeply at low speed. The Bf-109 had smaller wings which made slow speed turns more prone to stalling, but it had a trick up its sleeve: automatic leading edge slats that popped out and enabled turning at high angles. But later in the war, ever-increasing engine power and the change to high-speed tactics made these low-speed features superfluous. The Zero relied on its large wing area like the Spitfire, and its very light weight, to excel at turning at low speed.

The ability of the Spitfire and Bf-109 to evolve kept them competitive.

What more could have been done to keep the Zero more competitive, if not a war-winner then at least not cannon fodder? It needed to make the transition from low speed turning combat to high speed fighting.

For a start, it needed a new engine. The Sakae-21 engine built by Nakajima was extremely reliable, but low-powered at 1100hp. The Zero had originally been designed for the Mitsubishi Kinsei engine which started with equal power with the Sakae, but later mark Kinsei-62 had been successfully tweaked to 1500hp by 1943.

The Kinsei-powered Zero was an aircraft that almost came into being, except for interference by Navy officers. The designers at Mitsubishi had been overruled at the Zero’s introduction in 1940 and ordered to fit the fighter with the inferior Zuisei engine, then with rival Nakajima’s Sakae. The Navy also overruled the now-tweaked 1500hp Kinsei-62 for the A6M5 upgrade in 1943 due to the necessity of retooling the aircraft factories to produce a different engine mount; pilots would pay very dearly for the stubbornness of the Navy admirals.

A more powerful engine would give the Zero pilot more options for pursuit and escape, and more extreme vertical maneuvers which the Zero already excelled at in addition to its low speed maneuverability. Had the Zero been equipped with the Kinsei in 1940 as intended by its designer, the upgrade would have involved tweaking its engine rather than outright replacement involving redesigning its engine mounts, cowl and plumbing.

The reduction in wing size was a step in the right direction, improving the roll performance and increasing its speed. There was still one very large handicap: at high speed, the ailerons became unusable.  The pressure exerted by the airstream on the ailerons was too much for human muscle to overcome; controls were operated directly by the pilot with cables or rods connected directly to the control stick and rudder pedals. Very few  aircraft had power assisted controls. The Zero’s large ailerons gave it excellent turning characteristics at low speed but were impossible to operate at high speed. At high speed, the Zero could loop up or dive but was unable to roll sideways: rolling was the prelude to turning. It made the fighter too predictable in high speed combat.

Jiro Horikoshi, the Zero’s designer, had originally installed servo tabs on the ailerons to assist high speed roll. A servo tab is a small flap hinged to the trailing edge of the aileron. It requires less force to operate against the high speed airstream due to its small size, and it uses the force generated by the airstream to help move the aileron in the opposite direction the tab is moved. This did indeed free up the ailerons at high speed, but it encouraged the Zero pilots to make extremely aggressive high speed turns that overstressed the wings. Horikoshi was forced to remove them.

The Zero would need strengthened wings as well as servo tabs in order to perform high speed roll and turn. In the meantime, pilots would have to change their style of flying, making the famously steep turns only at low speed, and to roll and make shallower turns at high speed.

Japanese Army fighter aircraft of the Second World War

Japanese Army fighter aircraft of the Second World War
The Imperial Japanese Army and Navy had separate and rival air forces with their own aircraft: separate bombers, fighters, transports, and reconnaissance. Rivalry between the two arms was intense, preventing them from sharing resources, research data and even spare parts. In some regards, the Army air forces had better aircraft than the Navy especially from mid-war onwards.

On the other hand it might be said that the Army was using too many types of fighters, limiting large scale production.

Army Fighters
Nakajima Ki-27 ?/Nate/Abdul

The Imperial Japanese Army Air Forces’ (IJAAF) first monoplane fighter introduced in 1936. Lightweight construction, non-retractable landing gear, highly manoeuvrable and performed well against Soviet Polikarpov I-16 Ishak/Rata at the Battle of Nomonhan and over China.

The Army had held a competition for aircraft manufacturers to select a suitable fighter. Mitsubishi offered a modified Navy fighter that beat everyone else, but the Army was offended and refused to use a Navy design. The Ki-27 was designed to beat Mitsubishi’s Navy prototype (which later served the Navy as the A5M Claude).

The Nate was still in use at the beginning of the Second World War, although Nakajima had ceased production and the Army was bringing its successor to the front, the Ki-43 Hayabusa.

Nakajima Ki-43 Hayabusa/Oscar

Another highly manoeuvrable fighter in the IJAAF, and successor to the Ki-27. It was introduced in 1941, but even as the war began, some units were still flying the Nate. Although Nakajima and other manufacturers believed that power and speed with heavy armaments were the future, the Army insisted on lightweight, highly manoeuvrable fighters. Development was delayed by the Army’s insistence on high manoeuvrability at least matching the slower Ki-27. Eventually the introduction of combat flaps made it more manoeuvrable than the Zero.

It was mainly let down by weak armaments: two 7.7mm machine guns mounted above the cowl. The three support spars in the wings were too closely spaced to mount any weapon in the wings. Later the weapons were upgraded to two 12.7mm machine guns firing explosive rounds, but the rounds often exploded prematurely on the surface of target aircraft instead of piercing the skin and exploding within, doing terrible cosmetic damage rather than destroying the target.

It was also fragile and could not withstand much damage. Later versions backed the pilot seat with armour to reduce pilot deaths and also protected the fuel tanks, so that the fighter would break up instead of exploding, giving the pilot time to bail out.

Its manoeuvrability was phenomenal. Allied pilots reported seeing pilots perform double-double Immelmanns, horizontal spins, flip rolls, snaking vertical climbs, and extremely tight turns that would cause even a Zero to stall and crash. An Immelmann is a vertical half loop with the plane ending up flying in the opposite direction. Most aircraft including the Zero would be hard put to perform one, and these aircraft were doing four in succession!

Kawasaki Ki-61 Hien/Tony

Japan’s only fighter that uses a water-cooled engine instead of air-cooled radials. The Hien was introduced in 1943 and was mistaken for an Italian import, thus the Allied codename “Tony”.

While a sizeable number of pilots wanted lightweight highly manoeuvrable fighters, the Japanese Army hedged its bets based on the expert opinions of the manufacturers and commissioned several “speed fighters”, well armed, fast, and giving more protection to the pilots.

Kawasaki’s Hien de-emphasized manoeuvrability in favour of speed, although it still was a very good at turning by Allied standards. At introduction, it was the fastest fighter in the Japanese stable, and faster than most American planes in the Pacific. It had better armament than its contemporary Ki-43, with two cowl machine guns and two cannons.

Most Allied pilots had learned they could escape Japanese aircraft by a shallow power dive, outrunning them, but the Hien nullified this tactic because it too was a good power diver. It could outturn the faster American planes, and outrun the slower ones.

Its engine was a modified version of the engine powering the German Messerschmitt Bf-109E but shaving 40 pounds of metal to make it lighter, but this made the already complex engine very hard to build, with a high rejection rate. Japanese manufacturers found it difficult to match German precision in metal casting. It was also difficult to maintain in the jungle bases of the Pacific, and broke down often in the tropical heat.

While an excellent design, its unreliable engine prevented the fighter from achieving its potential. Engine problems frequently grounded the aircraft, and pilots often did not dare push the engine to maximum power. Sometimes they did and the engine would not deliver.

Its engine problems were solved in the Ki-100.

Unlike most Japanese fighters, the Hien/Tony was very sturdily built and could survive more damage. Not only were the fuel tanks protected and the cockpit armoured, the fuselage itself was very strong. In the final stages of the war, fighter pilots sometimes tried to destroy B-29 bombers by colliding with them. Most other aircraft used disintegrated killing their pilots, but Hien pilots would survive and parachuted safely to do it again!

Nakajima Ki-44 Shoki/Tojo


Introduced in late 1941, the Ki-44 Shoki was intended to be a bomber interceptor. As such, the design de-emphasized manoeuvrability in favour of speed and climb. Nakajima mounted the largest and most powerful engine they had on a small fuselage. It was also more heavily armed than the Ki-43, either carrying four 12.7mm machine guns, or two cowl machine guns and two wing cannons of 20mm caliber.

Most units were pulled back to Japan after the Doolittle Raid with some remaining in Sumatra. They saw action and were fearsome aircraft over Sumatra late in the War, although were less successful against B-29 attacks over Japan due to poor engine performance at high altitudes.

In the later stages of the war, Allied aircraft designers tended to favour power and speed over manoeuvrability for fighters. Having these very traits, interceptors such as the Shoki were found to be competitive with middle and late war Allied fighters, and found itself in fighter vs fighter combat as often as bomber interception.

Kawasaki Ki-45 Toryu/Nick

A twin-engined heavy fighter, intended as long range bomber escort, it was unable to outperform enemy single-engined fighters. Like its German counterparts (Me-110 and Ju-88) it was repurposed as a night fighter where it was reasonably successful, even though Japanese pilots relied on night vision instead of on-board radar as the Germans did. Japanese night fighter pilots were selected from among pilots with excellent night vision.

Like the German night fighters, the Toryu was fitted with fixed upward-firing cannons on the roof, to shoot up at the bellies of bombers. The Germans called it Schrag Musik (Jazz Music), but the Japanese had come up with the same idea on their own. The undersides of bombers were seldom equipped with defensive guns since most of the belly space was occupied by the bomb load, and this defensive blind spot was exploited by the Jazz Music guns.

In 1945 the Toryu (“Dragon Slayer”) found itself having to live up to its name, slaying B-29 superbombers that were incinerating Japanese cities with incendiaries.
Nakajima Ki-84 Hayate/Frank

This purpose-built fighter is widely acknowledged to be Japan’s finest, or at least the finest built in large numbers. Clean lines, powerful 2000 hp Homare engine, sturdily built (although not quite as solid as the Hien/Tony), and well-armed. It could do anything the new US fighters could do, climb and dive with them, pounce from above, give chase if they run, and with the combat flaps deployed, outturn the faster planes.

It was mostly let down by the unreliable Homare engine, rated at 2000 hp on paper but delivering 1500-1800 hp in practice, although it was more reliable than the inline powering the Ki-61. There were also problems with its landing gear, which was sometimes not properly heat-treated and could snap off on a rough landing. But overall, a fighter to be reckoned with.

Kawasaki Ki-100 Goshikisen/Tony

This is the Ki-61 Hien/Tony unleashed. While an excellent aerodynamically clean design, the original Hien had suffered from teething problems with its complex engine, which meant that pilots seldom pushed the fighter to maximum power.

That was to change in 1945. A US bombing raid destroyed Kawasaki’s engine factory, leaving hundreds of completed Hien airframes without engines. In dire straits, the Japanese high command ordered Kawasaki to experiment with fitting the aircraft with the Mitsubishi Kinsei radial engine. The results astounded everyone.

The engine was 300 pounds lighter, since it did not require an engine block to contain liquid coolant, nor pipes for them or radiator. Pilots now had 1500 hp to play with, and were no longer afraid to push the engine to full power. It was now possible to use boost, overpressuring the cylinders to momentarily give bursts of extra 300 hp.

Pilots tested the Ki-100 against the Ki-84 Hayate, and concluded that this fighter was better. This fighter is the Hien/Tony as it was meant to fly: a well-armed speed fighter on par with the Hayate.

However, coming as it did at very near the end of the war, meant that only a few hundred were built, with the first 200 or so being conversions.

(Japanese Navy Fighters to follow)



The hardships and sufferings to which Our nation is to be subjected hereafter will be certainly great. We are keenly aware of the inmost feelings of all of you, Our subjects. However, it is according to the dictates of time and fate that We have resolved to pave the way for a grand peace for all the generations to come by enduring the unendurable and suffering what is insufferable.

-Emperor Hirohito, surrender of Japan, 1945-

I seldom feel anything when people make speeches, because mainly it is fake and the words mean very little. But this, the Surrender Rescript of the Emperor, is of great moment, is not fake, and therefore is very moving.