Am I the only person in the world who's a fan of the Ki-43

[tomo pauk]

I wonder if the low top speeed of the Ki-43 was necessarily a consequence of the Japanese desire for maneuverability, or if it was fault of a lack of more powerful engines in Japan. People assume the Oscar and the Zero were slower than Allied fighters of their class (like the P-40) because the Japanese wanted planes basically for dogfight. I'm skeptical about this, because in order to enter in a dogfight, you have to reach your enemy first. If you can't or if this is difficult, it just doesn't make sense.

Apart from the Kasei, there was no powerful radials in 1938-40 for the Japanese engineers to choose from. It is my understanding that any Kasei Mitsubishi was to produce was dearly needed for the G4M that was in design proces. The Japanese have had no 3-engined bomber in pipeline until too late, so 2 x ~1500 initial HP was dearl needed for the combination of bombload/range/speed neccessary.
The Oscar and Zero were much faster than Nate and Claude, but Japanese have had a proble that Europe and USA were introducing ever faster aircraft in a much faster tempo than the Japanese themselves. The Zero and p-40 were in see-saw battel for performance, one sometimes faster, then another, depending on engine and how much they were burdened by firepower and protection. Installation of engine on the Zero got improvements much earlier than on the Oscar.

Just look at the Yak-3 for instance. Very light, very agile, but adequate in terms of performance. And as I have said earlier, the Zero did not had this performance issue against the Wildcat. It did lacked pilot and fuel tank protection, and dive speed, but not level flight speed. So it's pilot's could chase Wildcats in level flight without having to worry about performance. Now a Ki-43 against a P-40E, I guess the IJA pilot's must have felt lack of performance. Specially in the first production model of the Hayabusa.

Yak-3 introduced a tiny wing, of a thinner profile when compared with prevoius Yak fighters, that were already with small wings when compared with Oscar/Zero (nod for Soviets). Neither Zero nor Oscar were with thin wings, either (again a nod for Soviets). Almost a brand new aircraft. It also helps when low powered engine is a V12 rater than a radial (3rd nod for Soviets). The Yak 3 was a much later design (4rth nod), drawing from experiences of the major war against a formidable opponent.
A problem for the Yak-3 is that it was without the long range capabilities needed in Asia/Pacific, even if we attach the drop tanks on it. On the other hand, had the Japanese came out with an aircraft powered by Ha-40 V12 engine, featuring the tiny wings from the Ki-44...

Then, there was the interesting Ki-12 fighter from the 1930s, but IJA got cold feet and ordered the simple Ki-27.

 

[ChrisMcD]

I wonder if the low top speeed of the Ki-43 was necessarily a consequence of the Japanese desire for maneuverability, or if it was fault of a lack of more powerful engines in Japan.

For the Ki-43 I think the answer was yes, insomuch as that was the way that the specification was written and the way that the Japanese wanted that generation of aircraft to perform.

It's successor, the Ki-44 was optimised for speed and climbing performance and then the Ki-84 was a superbly rounded fighter - arguably the best Japanese fighter of the war. Nakajima were excellent fighter designers and worked their way to a superb final fighter.

I find the subject of Japanese engines interesting. AFAIK the Sakae was a development of the Rhone 14 series and as such was a very compact engine of superb economy, but not amenable to further development. The Mitsubishi Kinsei and Nakajima Homare were good, powerful engines but significantly bigger and, I believe, originally intended for bombers.

It took a while for the Japanese to accept that speed and climbing performance from high engine power were more important than maneuverability from lightness at all costs.

In all fairness the lightweight, "jockey fighter" was a popular idea in the early 30's in a lot of countries and the Japanese versions were undoubtedly the best. Zero and Hyabusa both

 

[Shortround6]

The Zero and Hyabusa were not really jockey fighters. Granted definitions changed over time (and with countries).
But the Zero and Hyabusa were within a few hundred pounds of contemporey fighters like the MK I Spitfire, the Bf 109E. the P-36 (or Hawk 75). Macchi 200, or even Lagg-3 (noraml take-off not max with under wing loads).

Jockey fighters were more like.

and later evolved to the the French Caudron 714 and 4 competitors

Very few of the late 1930s versions went much past 4500lbs clean for take off, if that, the Caudron pictured was 4145lbs, about 1500lbs lighter than a Hyabusa.

 

[tomo pauk]

...
Jockey fighters were more like.

...

Interesting fighter - what type was that one?

 

[Shortround6]

D.H. 77

 

[The Basket]

If the question is that the Hayabusa and Zero by 1945 is better than nothing and desperate measures call for the Hayabusa to be a front line fighter then I have no problem with that. Plenty of aircraft have historically played that role. Polikarpov I-16 and I-15.
However....Minimum fighter threat in 1945 skies of Japan for me is P-51 and minimum bomber threat is B-29. You must at least match both these machines. If you can't intercept a B-29 then you're not much of a fighter. The 'worst' aircraft you might meet is a Hellcat and that still has better performance than a Hayabusa.

 

[The Basket]

Is that the Vickers Jockey or the Venom? That was a weak engined fighter that had good performance.
Certainly good enough mid 1930s.

 

[Jenisch]

One can find on the internet mentions that a version of the Ki-43 III produced by Tachikawa from 1944 had a top speed of 358mph. This is quite comparable to the P-40. It would be a decent plane for 1942, and to some extent 1943. If this speed was indeed achieved by the Oscar, and it's power curve was comparable to the P-40 in different altitudes, then I guess the plane was not that bad. The airframe was not that bad. It just needed a better engine. The "only" problem is that this engine should have been fitted to the plane in 1941, not in 1944!

 

[taly01]

The P-40 is a good contemporary of the Ki-43 to compare with. The P-40 did 350-370mph over its entire production run, whereas the Ki-43 improved 310-350mph. But the lack of guns was a flaw that never was solved. P-40 pilots said their plane could "take it" from the 2xMG of the Oscar, but if they hit an Oscar with 6x0.50 it really blew up.

 

[The Basket]

P-40 is only a good contemporary because it was available.
If you compare Hayabusa with Me109 or Spitfire it becomes a different sport.
First flight was 1939 for the prototype which compares with the FW190 also both aircraft entered service roughly same time
And the 190 absolutely is a trillion times better than any Hayabusa.

 

[GregP]

I seriously doubt the Japanese pilots felt any lack of performance since almost ALL military pilots, both then and now, train on their own aircraft. Nobody has them fly, say, 3 aircraft and then select the worst-performing one.

If they flew the Hayabusa, it was the ONLY fighter they had flown and outperformed ALL the trainer sthye had ever seen by a large margin.

They certinaly had NO disadvantage in maneuverability versus the USA, but may have severely wished for bigger and more numerous guns, plus maybe more ammunition capacity.

Very few worried about the armor or lack thereof since, if they survived, they had never been "hit."

 

[MiTasol]

I'll have to scratch the idea of installing the Ho-3 without the wing going through a major redesign - looks like the wing was with at least 3 spars - cutaway.

hi Tomo

This cutaway has at least one error and that is the drop tank is very wrong.

I will have to find my photos but the Ki-43 drop tank installation was a far more advanced design than any equivalent US drop tank of the period.

I will compare it with the P-39, P-39 and P-40 installations using photos.

Once the tank was dropped the K-43 wing was totally clean whereas the equivalent American aircraft were festooned with aerodynamic arse-holes

Mi

 

[taly01]

Most pictures of Ki-43-III i've seen have pylons fitted to the wings even when no ordnance is been carried.

Still thinking about only 2 x MG guns on all the Ki-43, a single 20mm was really essential by 1943, the Yak-9 and Bf109 (both 30,000 built!) mostly relied on a single 20mm.

 

[Greg Boeser]

By the time the Ki-43 III came out, Ki-43 units were pretty much relegated to ground support (and Kamikazes). The air superiority and intercept roles had been taken over by Ki-44, Ki-61, and Ki-84 units.
The illustrious 64th Sentai, for example, finished the war performing ground support in Burma.

 

[Ivan1GFP]

Hello Gentlemen,
I had just been searching for data on the Ki 43-II and stumbled upon yet another interesting thread.
I don't suppose anyone here would know what the capacities of the fuel tanks were on the Ki 43-II?
I already have the numbers for the Ki 43-I.
Anyone happen to know where I can find what the throttle settings and RPM were for Military, Normal, and Emergency Power?
The numbers from TAIC documents don't seem to match up with the Sakae 21, so I am not inclined to trust them for the Ha 115.

From these discussions, I am inclined to agree with GregP that the late model Hayabusa was a pretty dangerous adversary up until the very end of the war. Yes, there was about a 20-50 MPH advantage with the typical Allied fighter in 1945, but this is at their critical altitude and that I not where the battles were being fought in general. At low altitude, the maximum speed disadvantage is less for Hayabusa (and Ki 100 also) and the engagements do not start at maximum speed.
Here is where the Hayabusa had an advantage. It was light and had a lot of power for its weight and had very fast acceleration at low speeds.

For production purposes, I figure the Hayabusa was treated pretty much like the American F4F Wildcat except that a successor did not come along fast enough. The Ki 44 Shoki was not really the successor. It was a pure interceptor in design. The Ki 84 Hayate was the successor and when production was ramped up, Hayabusa production was relegated to Tachikawa just as Wildcat (F4F-8 / FM-2) production went to General Motors.

I find it interesting to compare the Ki 43 to the A6M Zero. It seems to me that the Ki 43 had many advantages over the A6M.
It had a little less speed in general but had a much better roll rate especially at high speed and probably had at least as good firepower.

- Ivan.

 

[Shortround6]

Firepower was pretty dismal compared to the A6M Zero. Most Ki 43 IIs had a pair of 12.7mm machine guns, and when synchronized the rate of fire wasn't all that great (although better than the US .50) however it used a much smaller cartridge than the US .50 which meant a smaller bullet and lower velocity.

Japanese Army and Italian cartridge is 3rd from left. Japanese Navy 13.2mm is 4th from the left and is pretty much comparable to the US .50 (1st on left).
The IJA did use exploding ammo but usual content was about 1 gram or under per projectile compared to the 10 grams or so in a 20mm Hispano.

 

[Ivan1GFP]

Firepower was pretty dismal compared to the A6M Zero. Most Ki 43 IIs had a pair of 12.7mm machine guns, and when synchronized the rate of fire wasn't all that great (although better than the US .50) however it used a much smaller cartridge than the US .50 which meant a smaller bullet and lower velocity.
Japanese Army and Italian cartridge is 3rd from left. Japanese Navy 13.2mm is 4th from the left and is pretty much comparable to the US .50 (1st on left).
The IJA did use exploding ammo but usual content was about 1 gram or under per projectile compared to the 10 grams or so in a 20mm Hispano.

Hello Shortround6,
I know we are going a bit off topic and I started it.
As I see it, the A6M series, especially the A6M2 before the fighter-bomber versions had only 60 rounds for each 20 mm cannon.
That meant that each cannon was only good for about 3-4 bursts before it was done. The rest of the work was done by the 7.7 mm MGs.
The Ho-103 was basically a Browning gun firing the Italian Breda 12.7 mm x 81SR round.
Yes, it was a small round but velocity (795 meters / second or around 2612 fps) wasn't too bad and it typically used an explosive shell.
Now one might argue that there was not a significant quantity of explosive and perhaps this was correct and perhaps not.
The original Italian cartridge was much more powerful than one might expect as was described by a Hurricane pilot who described the damage on his aircraft. The effect was not atypical of a 20 mm hit and a single hit had almost blown through his wing spar.
There was also a problem with the Japanese projectiles at one point in which they would detonate as soon as they left the muzzle of the gun.
It was necessary to put armour plate under the muzzles to avoid engine damage and this is not even from a direct hit.

As for the problems in synchronizing these guns, I believe there might be a bit more to the story.
Note that the problems with reduced firing rates was noted for the Ki 43-I but not for later versions.
One doesn't read about the Ki 43-II pilots replacing one of their 12.7 mm guns with a 7.7 mm MG.
I am suspecting it was because of the synchronizing mechanism because if it was the typical type, it would be attempting to fire the gun once in each gap between propeller blades.
With a two blade propeller, if you miss one cycle, it is a fairly long delay. It is less with a three blade propeller.
I am not suggesting that there was not an issue but rather than the two blade propeller made it more visible.

The Ki 44 also used the 12.7 mm Ho-103 as a cowl gun without the same horrible reputation.

Now keep in mind also that the 20 mm Ho-5 cannon also was a Browning design with an even slower cyclic rate (850 rpm versus 900 rpm).
Note that the Ho-5 was used as a cowl gun on the Ki 61-Id, Ki 61-II , Ki 100 and the Ki 84 and was even tested on the last Ki 43-III that did not go into production before the war ended.
If all Browning guns were such an issue to synchronize, then why would they continue to be used as cowl guns even on later aircraft?

- Ivan.

 

[Shortround6]

One reason they were used as synchronized guns was because nobody wanted to put a Vickers gun in the wings

Once you have the plane laid out with gunbays and ammo boxes, it is easier to replacement guns where the original's were.

Both the IJA and IJN used versions of the Vickers gun in 7.7mm and even the British rarely (and never on planes that went into combat) put a Vickers gun where a crewman (or pilot) could not reach it.

All of these guns lost 10-20% of their rate of fire when firing through the prop. The US .50 was one of the worst (may have lost even more than 20%) but take another look. With the length of the cartridge you have a fair amount of travel for the bolt. Please remember that these guns pulled the round backwards out of the links before moving the cartridge forward into the chamber.

Number of blades shouldn't have a lot to do with anything. Sakae engine did 2600rpm and used a 0.69 reduction gear? (corrections welcome) so prop was turning 1794rpm (?), with a 900rpm machine gun that is one shot every two full revolutions of the prop, regardless of number of blades. A slightly slower gun may run into more trouble. Machine guns also don't fire real evenly unless a lot of care is used setting them up and the ammo is very, very good. Gun is advancing the belt and depending on weight of belt and arrangement (lots of short layers or a few long layers) that can slow the guns down. US rather famously didn't test prewar installations with full belts and ran into all sorts of problems. You may average 14 shots per second but that doesn't mean the the time between shots doesn't vary.

Synchronizers often fired the gun when the blade was clear vs stopping the gun when the blade was in the way. It may not sound like it but that is a distinct difference. Look at the example again, a 3 blade prop on a Sakae is going to swing 8 or 9 blades past a 7.7mm gun for every time the gun fires in theory.

Two 12.7 guns may have been good armament in the late 30s or even 1940 but it was falling behind in in 1941/42. Japanese pilots in Ki 43s did bring down a number of B-24s but the most favored tactic was to attack from the front (pre nose turret) and use 3-4 fighters, one behind the other to attack a single bomber in the formation. In other words they were using 3-4 planes to bring the same firepower to bear as an single American or British fighter could.

 

[parsifal]

There is simply no comparison in the firepower of the Ki43 to the firepower of the A6M in that critical mid war period.

The Naval 1937 specifications for the 12-Shi fighter called for an armament of two 20mm drum fed cannon, with 60 rpg, two 7.7mm machine guns with over 600rpg and provision for two 60kg bombs. Soon after production of the A6M3 Model 32 commenced (in the latter part of 1942), ammunition supply for the cannon was increased from 60 to 100 rounds per gun, which I think were altered to a belt feed system, and this armament was carried forward to the Model 22 (see below). The designation Model 22KO (A6M3 Model 22a) was used to denote replacement of the standard cannon with the long-barrel type. In a search for even greater hitting power, a few Model 22s were experimentally fitted with 30mm cannon and operationally tested at Rabaul.

Engine change to 1130hp Sakae 21, and removal of the folding wingtip section, giving a clipped wing. To retain the centre of gravity position with the heavier engine, the latter was moved back towards the bulkhead. This reduced the fuel tank volume thus reducing the combat radius.

A6M3 Model 22: Adding the original folding-tip wing to the Model 32 engine/body combination, and incorporating a 12 gallon fuel tank in each wing to reclaim lost range. By the time the Model 22 reached production, the Model 52 was approaching operational status; thus the Model 22, appearing in combat after the Model 32, had a short operational life. 560 were built late 1942 and early 1943 (this figure is thought to include Nakajima production).

The 7.7mm machine guns, with a magazine of 680 rounds per gun, were mounted to fire over the engine cowl and through the propeller arc. These weapons were similar to the Army's Type 89 gun, a derivative of the Vickers LMG. It used disintegrating belt ammunition, could fire at 1000rpm, had an effective range of 600m, a muzzle velocity of 2460ft/sec and had a weight of 26lb per gun.

The wing armament comprised various versions of the Type 99 cannon, a version of the Oerlikon 20mm weapon, manufactured under licence by the Dai-Nihon Heiki Company. The versions used in the Model 22 appear to have been drum-magazine types, but later models were belt-fed. The long-barrel type used in the Model 22a were known as the Model 2 Mark 3, and had a rate of fire of 490rpm with a muzzle velocity around 2000ft/see and a range up to l000m. The 30mm version, known as the Type 5, was fed from a 45-round magazine and had a muzzle velocity of 2460ft/sec.
Aiming was by means of a Type 98 reflector gunsight (based on the German Type 99 I believe), and a Type 89 camera-gun could be fitted to the port wing root.

 

[Shortround6]

Early war many of the Ki 43s had either a pair of 7.7mm or one of each.
Now by later in the war perhaps the factories and armorers had figured out how to keep the rate of fire of the 12.7 gun up. I don't know.
I have hit some information that seems to indicate that the Japanese bought 2 million rounds of 12.7mm HE ammo from the Italians but it is a gaming site so.....

Later in the war the Japanese Navy started sticking 13.2mm guns into the Zero and thus a Zero with two 200m guns and two 13.2mm guns in the wings had a very equivalent amendment to an American plane with six .50 cal guns.

I would note that most Japanese army fighters only carried 250rpg of 12.7mm ammo which affects combat duration. Less than 20 seconds firing time even with slow firing guns.