Nakajima Ki-43 Hayabusa / OSCAR
1939
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Nakajima Ki-43 Hayabusa / OSCAR

With its relatively low-powered radial engine, two-blade propeller and twin rifle-calibre machine-gun armament, the Nakajima Ki-43 Hayabusa (peregrine falcon) was the most dangerously underestimated Japanese fighter of the early months of the Pacific war; yet, with its outstanding manoeuvrability, it gained complete mastery over Brewster Buffalos and Hawker Hurricanes in Burma. It was the result of a 1937 design which emerged as a light- weight fighter-bomber that required no more than its 709kW to meet its speed demands. In common with other Japanese fighters of the time, however, its armament was puny by RAF standards, and it possessed neither armour nor self-sealing fuel tanks. As the Allied air forces pulled themselves together after the first shock of defeat, the Ki-43-I's weaknesses were discovered and increasing losses suffered, resulting in the introduction of the Ki-43-II (codenamed 'Oscar' by the Allies), with pilot armour, rudimentary self-sealing fuel tanks and reflector gunsight; the engine was also changed to the 858kW Nakajima Ha-115 radial which increased the top speed to 530km/h, roughly the same as that of the Hurricane Mk II. The Ki-43-IIb entered mass production in November 1942, first with Nakajima and six months later with Tachikawa. Final variant was the Ki-43-III with 917kW engine and a top speed of 576km/h, but relatively few examples reached operational units. The Ki-43 was numerically the most important of all Japanese army air force aircraft, production totalling 5,886, plus 33 prototypes and trials aircraft.

Nakajima Ki-43 Hayabusa / OSCAR


Specification 
 MODELKi-43-IIb
 CREW1
 ENGINE1 x Nakajima Ha-115, 858kW
 WEIGHTS
    Take-off weight2590 kg5710 lb
    Empty weight1910 kg4211 lb
 DIMENSIONS
    Wingspan10.84 m36 ft 7 in
    Length8.92 m29 ft 3 in
    Height3.27 m11 ft 9 in
    Wing area21.4 m2230.35 sq ft
 PERFORMANCE
    Max. speed530 km/h329 mph
    Ceiling11200 m36750 ft
    Range w/max.fuel3200 km1988 miles
 ARMAMENT2 x 12.7mm machine-guns, 2 x 250-kg bombs

3-View 
Nakajima Ki-43 Hayabusa / OSCARA three-view drawing (752 x 1003)

Comments1-20 21-40
Ron, toolkeeper123=roadrunner.com, 14.04.2014

I was just wondering about the margin of improvement the 'butterfly' combat flaps gave the turn performance of the Nakajima fighters.
They enabled an Oscar pre-service test plane with more features than the typical production model of 19 lbs/sq ft wingloading to turn at least as well as a Ki 27 Nate (unknown version) typically with 16.4 lbs/sq ft wingloading but without the new combat flaps. Those wingloadings are for production versions but the planes in the comparison should be relatively close to these. If anything the loaded down test Oscar is even more remarkable to turn so tight.
I don't know the non production figures.
But in broad terms the flaps were good for equalling at least 2.6 lbs/sq ft difference in wingloading.
Enough to go from a thumbs down to a thumbs up by the test pilots.

Think what this means for the Tojo and Frank wingloadings. They had these flaps too. Subtract in effect 2.6 lbs/sq ft from theirs too. 37.7 is effectively 35.1 for the Ki 44-IIb
and 35.1 is like 32.5 for the Ki 84-Ia in a turn... more or less. Again these are based on typical known production loaded weights unlike the test comparison.

Point is you can't judge the turn performance merely by their wingloading or they may surprise you.

Ron, toolkeeper123=roadrunner.com, 14.04.2014

Hey Hiroyuli,
You're right. They say about 1,000 Ki 43-IIIa Oscars were made in WW2.

Too bad it just had the 2 MGs.
No mass production of the 20 mm cannon armed Ki 43-IIIb seems to have occurred in time.

Ron, toolkeeper123=roadrunner.com, 24.12.2012

Hi X,
Anyone would agree at least at first.
But bear in mind most Hayabusas had light machine guns or a mix of one reliable 7.7-mm and one 12.7-mm that was less reliable. Only later did they improve to the point of twin heavy machine guns. Still they had claimed more allied planes than any other Jap fighter! And mostly US planes tough as any in the war. The difference that I suspect accounts the most for this would be that no allied plane could shake one on their tail close-in (short of diving away) like they could a Luftwaffe plane. If the Ki 43 pilot (and his buddies) had all day to shoot at you, it had enough ammo to do damage; but if you tried the same on his six, its like trying to swat a fly (or a swarm of flies). Anyway, that's my opinion.
Too many Allied pilots were slow to learn not to give the Oscar the firing time on target required.
Overclaiming is another factor but not so much more so than with any other Japanese fighter type.
Also the Ki 43 and Ki 84 confused Allied pilots who mistook one for the other with favorable consequences for the Nakajima pilots. Just take the death of ace Tom McGuire for instance.

Of course by mid-war, the slow (max. speed) but quick (accelerating) Oscars were losing the battle left and right despite many above average pilots, but that's true also in the rest of the Axis. Against the Japanese (especially Oscars and Zeros), US pilots learned their lesson and kept up their speed with hit and run tactics only.

X, 07.07.2012

2 x 12.7mm machine-guns are totally useless in fierce battles like the ones over Europe

Ron, toolkeeper123=roadrunner.com, 14.04.2012

I want to make a slight correction to my last post.
The Ki 43-II got the more powerful engine and the IIa got the armored seat etc.. in Nov. 1943 as I said but the A6M5b entering production in June only had the armored glass. The armored seat came in the A6M5c starting production in Oct. 1944 - 11 months after the Hayabusa and furthermore the Zero did not get a more powerful engine and performance was degraded compared to the Ki 43-IIa. So for whatever it's worth, the Zero needed the new 1560 hp MK8P Kinsei-62 by then as planned by the design team (A6M5 in time for autumn 1943 combat) but nooo! Only the postwar A6M8 got that thanks to the Navy higher-ups.
So the armor issue makes the Oscar look good when compared to the Zero at least.
So the Zero became the kamakazi standard.

Ron, toolkeeper123=roadrunner.com, 11.04.2012

I believe the last pre-series Ki 43 had the experimental 1150 hp Ha-105, pilot armor, and 12.7 mm cowl guns in 1940 and still surpassed the Ki 27 (Nate) in maneuverability due to the new combat flaps. Unfortunately on January 9, 1941 it began production with the old but plentiful 7.7 mm guns and the underpowered 975 hp Ha-25 radial and you guessed it, armor protection was thus all unloaded as a result!
Why make things difficult to mass produce? Right?
Thus it didn't have to be obsolete off the bat but it was for expediency. Big mistake!
The cost in pilots lost proved too high and those missing upgrades were slowly restored over the years. In the Ki 43-Ib had mixed armament of one 12.7 mm and one 7.7 mm. The Ki 43-II had the Ha 115 type 2 motor with 1150 hp at just under 10,000 ft. By November 1943 the Ki 43-IIa had it's armor back. 2 years gone and we're almost back to 1940 prototype level! It had TWO 12.7 mm guns though. That was on it's way too. Patience...
I must admit that the A6M Zero was still without any armor until mid 1944 by comparison. And after that it's performance constantly fell while that of the Ki 43 surpassed it. The Hayabusa only progressed... then the Ki 84 Hayate replaced it (Ki 44 as well) and in good numbers too. It's Mitsubishi rival was the ill fated A7M Reppu (Sam) no show. Credit Nakajima!

Ron, toolkeeper123=roadrunner.com, 31.12.2011

Itokawa and his design staff were not proud when they built the first Nakajima prototype to the unrealistic requirements of the JAAF. It was rejected by the Army as a result. Demoralized, the Itokawa's team set their own more realistic goals, trying different variations of construction, engines, and so on, unhampered by the initial contract specs and design concessions. By the 12th prototype, it was accepted. After the next 10 experimental craft, combat flaps were added for phenomenal turns. Production was now begun.
I found that interesting, compliments of Richard M. Bueschel's Military History.

y.k, 18.12.2011

Yes.
After the end of WW2 captured Japanese planes were operated in Indochina.

hedgehoghollow.com/awoic/japan.html

Naga, 14.12.2011

My limited knowledge of this aircraft does not cover users, but somewhere I heard that France operated a small number of the type. Is this true?

Aaron, eaglefeather43410=yahoo.com, 10.07.2011

Ron,
The A6m2 compared to the Ki.43-1 was only more maneuverable over all in the vertical plane. The Ki.43s tighter/faster turn, quicker roll rate and faster acceleration gave it dominance on the horizontal plane. Fire power and top speed being the A6m's only advantage. Top speed does not come into play in swirling dogfight.

Ron, toolkeeper123=roadrunner.com, 04.07.2011

"As compared to the Mitsubishi A6M2 Reisen, the Ki-43-Ic had a substantially lower wing loading but was nevertheless slightly inferior to the carrier-based fighter in overall maneuverability. The A6M2 was superior to the Ki-43-Ic in zoom climbing speed, although the Ki-43-Ic had a slight edge over the A6M2 in steady climbing rate to 16,400 feet. The primary weakness of the Ki-43-Ic was its light armament..."(Parker info.com).
It had twin 7.7-mm cowl guns at first.
The Nakajima fighters were known to be more work for the pilot in aerobatics than the Zero. The Ki 43-I did 308 mph max. The A6m2 did 331 mph and at a higher altitude despite the higher ceiling of the Oscar. This is before either plane clipped it's wingspan for roll rate.

The record shows Buffalos of Malaya etc.. did make aces against more Hayabusas than Zeros. And my former post wasn't my invention. It's what I read.
I suggest they utilized it's dive advantage for hit and run and steered clear of the cannon armed Zeros (my guess).
Pilot quality is probably a big factor between the Japanese navy and army pilots too. Remember the incident with Russia?

Aaron, eaglefeather43410=yahoo.com, 26.06.2011

aiergirl,
All facts aside, I am very currious as to why you believe a Buffalo could hang on the tail of and Oscar but not a Zero.?
The Ki-43 can outroll, outturn, out accelerate and over distance can out climb the contemporay A6M.

Aaron, eaglefeather43410=yahoo.com, 23.06.2011

Sorry,
I almost forgot the most important features of the Japanese fighters. The large ailerons of the Zero and the combat flaps of the Peregrine Falcon. These features made these two aircraft the tightest turning monoplane fighters of WW2 with one sole exception. The Ki.27 (Nate). (Not real sure about the A5M2-4 Claud)...?

Aaron, eaglefeather43410=yahoo.com, 23.06.2011

aiergirl,
I am truly sorry about your sensitivity, but those are the specifics and they DO make the difference.

Aaron, eaglefeather43410=yahoo.com, 23.06.2011

Hi aiergirl, and WOOPS!,

OK, it is possible that a skilled Buffalo pilot could lock onto the tail of a Ki.43 or A6M2 and do some real damage if he was facing an average JAAF/JNAF pilot. That is true with just about all aircraft of similar power. BUT given pilots of even fairly good skills and the answer is NO WAY...PERIOD.
First the most maneuverable Buffaloes to see combat were the B-239 flown by the Finnish. They mostly carried 4x12.7mm guns. They were much lightened and somewhat modified from the Buffaloes that the U.S. and U.K. put into service. They had early self sealing gas tanks and mild pilot armor. Power was 1,000hp at War Emergency compared to 950 (A6M2) and 980 (Ki.43-I). Now for the important information that determines the ability to maneuver in the vertical and horizontal planes. The power loading of these A/C at Combat power and weight: B-239: 5.325 lbs/hp. A6M2: 5.16 lbs/hp. Ki.43-I: 4.6 lbs/hp. Translation: the lower number means better acceleration, climb and turning ability at lower speeds. The wing loadings at Combat power and weight were: B-239: 25.5 lbs/ft2. A6M2: 20.3 lbs/ft2. Ki.43-I: 19.07 lbs/ft2. Translation: The lower the wing loading the better the ability to turn tight at lower speeds.
The F2A-1 (B-239) would have been one of the most maneuverable aircraft in the U.S. inventory at the beginning of the war. But, it would have been the slowest (301 mph) and the worst equipped.
Finnish pilot Hans Wind did exceptional against poorly trained Soviet pilots in I-153s and even Yak-1s. But he didn't have to face Saburo Sakai in a Zero or Satoshi anabuki in an Oscar.

aiergirl, 20.06.2011

I'm a little over-sensitive about wartime misinformation and over-simplification. A skilled Buffalo pilot could hang with a Ki 43-I but not an A6M2 for example. Knowing specifics could make the difference.

, wholesale=gmail.com, 20.06.2011

Nakajima Ki-43 Hayabusa

Ron, toolkeeper123=roadrunner.com, 05.11.2010

Some tidbits I recently learned about the death of McGuire:
1. There was a 20-mm shell in his P-38s wreckage.
2. The 2 surviving U.S. pilots thought they were in a fight hat dayt with only one Nakajima fighter, until after the war.
They didn't know the plane that shot down Rittmayer was a Ki 84 Frank. They thought it was the same Oscar that started the fight.

Thus the story we know is cooked perhaps. Just a little bit.
The drop tanks used as the reason for his death... something more happened.
True the Hayate was new in the area, maybe mistaken for an Oscar at that point. But that 20-mm shell didn't come from Akira's Ki 43 Hayabusa. It came from Mizunori's Ki 84.
Am I wrong? Did we buy a cover story to save embarrassment?

Ron, toolkeeper123=roadrunner.com, 31.10.2010

In 1942 P-40s and P-39s were out-numbered by swarms of Oscars the limited firepower of the Ki 43 was not an individual 1 on 1 comparison. They could gang up on the US fighters like bees.
Their combined victories could have also lent itself to inflated individual claims in my opinion.
It has been suggested that US P-39s in particular fell victim to the Oscar in comparison to Soviet P-39s fighting the Luftwaffe. While the P-39 could shake a Bf 109 off it's tail at low level, a Ki 43 on it's 6 had all day to pierce the vulnerable coolant lines of the inline engine behind the pilot. There was no out-turning an Oscar. The P-40s may have returned home while the P-39 often didn't because the Warhawk's engine was in the front and the Oscar was in the back. After the US tactics changed and the P-38s and other new US fighters arrived, the Oscar would simply get bounced from on high. However, lest the Allied pilot slipped and did a close-in maneuver and lost speed, the Ki 43 would latch on to the overweight fighter long enough do do damage.

Ron, toolkeeper123=roadrunner.com, 28.10.2010

It is sobering to read that the Oscar racked up more victories than any other Japanese fighter.
50% of all kills by the Japanese were at the hands of Oscar pilots! It's no wonder it was the favorite of so many IJAAF aces. That's interesting when you consider the Zero outnumbered it almost 2 to 1.
On the other hand, individually the very top aces of the Imperial Navy reached scores about double the Armies best (2 or 3 upwards of 100 or more vs 3 or 4 in the 50s).
Also only 5 or 6 IJAAF aces outscored (the top US ace) R. Bong's 40 kills, while 11 IJNAF aces did likewise.

The Ki 43 like the A6M did their Ninja thing like only they could.

1-20 21-40

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