How capable was the Ki-44?

[Shortround6]

I like the Ki-44. It's the first Japanese fighter that was robust and armoured, trading light weight and fragility for survivability. It just needs a better engine.

When??

In Dec 1941 with the 9 preproduction aircraft used for combat trials?
The Ha-42 installed is claimed to have had 1250hp at 4,000 meters which is not bad for Dec 1941 and certainly better than 970hp at 3400 meter engine used in the Ki-43 I.
The Ha-109 engine giving 1320hp at 5250 meters the fall of 1942 was certainly better than the 980hp at 6000 meters used in the Ki-43 II.

Maybe they could have used more power later but much lauded engine used in Ki-100 was only good for 1250hp at 5800 meters. The Ki-100 is bit over rated.
What the Ki-44 needed was slightly bigger wing and fuel tanks in the wing to raise fuel capacity a bit for a good performing general purpose fighter instead of a specialized interceptor.
The Ki-44 was slightly faster than the Ki-100 and climbed a lot faster and had a similar ceiling. With a bit bigger wing they could have had the Ki-100 (or close) in the Spring/Summer of 1943.

 

[Steamed_Banana]

I like the Ki-44. It's the first Japanese fighter that was robust and armoured, trading light weight and fragility for survivability. It just needs a better engine.

It's a small plane, a lot smaller than I think people realize. Smaller wingspan than a Bf 109.

 

[beers]

and I think Corsairs are fairly close to a Hellcat in turning circle though I haven't looked at it in a while

Japanese pilots respected the Hellcat far more than the Corsair or P-38 because it specifically was capable of keeping up enough in a turn to still shoot them. It also had the largest wing area of any single engine WW2 fighter.

 

[GregP]

The general consensus is the Hellcat could out-turn the Corsair.

I've never heard a time for the F4U Corsair.

I heard 20.5 seconds and 20.0 seconds for the F6F Hellcat for a 360° turn at 10,000 feet and best corner speed.

 

[Steamed_Banana]

Ok but the wing loading on a Ki-44 with those tiny, weirdly shaped wings was a not very svelte 38 lbs / sq foot. i don't know how efficient the wings were, but that compares fairly well to both the F4U and the F6F, depending on loadout, for example based on this (which I find here on this site, where you can find a lot more detail)

...especially keeping in mind that US units encountering the Ki-44 will usually be over the base of the Ki-44, having flown there some distance, so they'll be a little bit lighter than their maximum fuel load.

And the above chart does seem to indicate that while F6F does have a lighter wing loading than the F4U, it is indeed pretty close, particularly for the earlier mark. F4U wing loading actually wasn't bad, and it's roll rate was quite good which also matters a lot in a dogfight. The F4U at some point did have a maneuvering flaps setting at 10 degrees though this would only be used at lower speeds.

Speaking of which, you also mentioned the Kittyhawk, the P-40E's wing loading is around 35lbs/ sq ft fully loaded, and it has a very high roll rate for WW2 fighters, like in the top 5 for major types. From what I understand, it also had flaps which could be partly deployed via the hydraulic switch on the control stick to any amount you wanted. P-38 had a poor roll rate initially but once they got the boosted ailerons they were right there in the top 3 or 4 IIRC. P-38J and L also had improved maneuvering flaps settings and of course, more power.

 

[Steamed_Banana]

Soviet 360 degree turn time test results in seconds (some turn different rates in different directions, which is why you see two for some of these. These turn times are also low altitude - 1,000 meters I believe)

P-40C -18.0
P-39D-2 -17.7 / 18.7
P-400 -18.2 (P-39D equivalent, former RAF, 20mm cannon plus nose and wing guns, 1942)
P-400 - 18.2 (as above, but no wing guns, 1942)
P-39L - 18.5 (1943)
P-39N-1 - 19
P-39Q-15 - 20/21
P-39Q 19.5 (1943, with gunpods)
Spitfire Mk VB -18.8 (1943)
Spitfire LF Mk IX - 18.5 (Merlin 66)
Spitfire F Mk IX - 17.5
Spitfire HF Mk IX - 19 (Merlin 70, 1945)
P-40E-1 CU -19.2 (1942)
P-40M-5-CU - 18.8 (1943)
Hurricane IIA -17/18 (1941)
Hurricane IIA - 19/20 (1941 with Vokes filter)
Hurricane IIA -19/20 (with 4 x 20mm ShVAK and Soviet 91 Oct fuel)
Hurricane IIB - 20.5 (1942)
Hurricane IIC - 20 (1943)
Mustang Mk 1 - 23 (Allison engine)
P-47D-10-RE - 26 (in 1944)
P-47D - 27/28 (in 1945)

Unfortunately the Soviets didn't test P-38s or any USN fighters. I've seen numbers of 18-20 seconds for different marks of the Wildcat, and 19.8-23.5 seconds for the F6F, and 20-24 seconds for different variants of the Corsair, but I don't know the sources for those numbers.

Japanese sources (quoted by Shores) for turn time for the Ki-43 was around 11-13 seconds, and the A6M between 14.1 and 17 seconds, depending on variant and load out, although I do not have a source for that.

German fighters are usually in the low 20s, with the Bf 109 being better than the FW, and Italian fighters a bit lower than that 19-20 range, Soviet fighters are in the 17-19 range, except for the Biplanes.

According to anecdotal claims in Shores "Bloody Shambles" vol III, the US made Hawk 75, operated as the Mohawk by the British in that Theater, could turn with the Ki-43-I and Ki-43-II

 

[Shortround6]

The Corsair is usually rated at rolling better than the Hellcat. Be careful here as the F6F-5 wee modified to roll better. They traded a bit of low speed roll response for better rolling at higher speeds so make sure you are comparing at the right time period. Most times the story for the Corsair is that they tried 17 different combinations of ailerons and cable routing to get the response they liked.
If it takes too long to roll 60 degrees or more you are not going to follow a good roller into a turn or you wont escape a a good one even if you can turn a little tighter once you have banked the needed amount. This is why the FW 190 was so dangerous. Wing loading was around 45lbs/sq ft depending on exact model and fuel load. But it rolled really well so to bank quickly and was noted for reverse banking (turning in the opposite direction once the other plane and committed to turning) .

And just comparing wing loading, while helpful, doesn't tell the whole story if combat flap settings are used. Hellcats and P-38s extended their flaps somewhat as they depressed to 8-10 degrees (?) adding square footage while altering air flow (changing lift co-efficient). P-40s may have been able to use a shallow flap setting but the flaps are split and the lower serface just hinges down.
Model

F6F

this is landing and not combat but even at a shallow setting you are going to get some additional area and you are not going to get the separated of air flow that the P-40 gets because the upper part of the flap turns downward a bit.
P-40 Flap helped with lift somewhat but it was also part airbrake.

 

[Steamed_Banana]

The Corsair is usually rated at rolling better than the Hellcat. Be careful here as the F6F-5 wee modified to roll better. They traded a bit of low speed roll response for better rolling at higher speeds so make sure you are comparing at the right time period. Most times the story for the Corsair is that they tried 17 different combinations of ailerons and cable routing to get the response they liked.
If it takes too long to roll 60 degrees or more you are not going to follow a good roller into a turn or you wont escape a a good one even if you can turn a little tighter once you have banked the needed amount. This is why the FW 190 was so dangerous. Wing loading was around 45lbs/sq ft depending on exact model and fuel load. But it rolled really well so to bank quickly and was noted for reverse banking (turning in the opposite direction once the other plane and committed to turning) .

Fw 190 rolled like it was on ball-bearings. The P-51 also seems to have changed a lot in this regard - the early Mustang Mk 1 / P-51A types rolled poorly, but the P-51B and later had a different Aileron rigging and rolled very well, especially at high speeds, by my understanding. Corsair as I mentioned also rolled very well at high speeds, i wasn't aware they had boosted roll in the F6F-5, that's interesting.

P-40 pilots did report using partial flaps on a couple occasions in interviews, I think just a very little bit. Often in a nose-down turn, a bit like what would be called a low-YoYo today. Robert DeHaven described doing this routinely.

And just comparing wing loading, while helpful, doesn't tell the whole story if combat flap settings are used. Hellcats and P-38s extended their flaps somewhat as they depressed to 8-10 degrees (?) adding square footage while altering air flow (changing lift co-efficient). P-40s may have been able to use a shallow flap setting but the flaps are split and the lower serface just hinges down.
Model
View attachment 850374
F6F
View attachment 850375
this is landing and not combat but even at a shallow setting you are going to get some additional area and you are not going to get the separated of air flow that the P-40 gets because the upper part of the flap turns downward a bit.
P-40 Flap helped with lift somewhat but it was also part airbrake.

I think some US Navy planes had flaps designed to "un-deploy" at higher speeds automatically to prevent their being damaged. Playing with flaps did pose risks!

I don't really understand the relative advantages of split, full (per above) and fowler type flaps for combat maneuvering, but I think both Ki-43 and the P-38 had the fowler type.

 

[Steamed_Banana]

And just comparing wing loading, while helpful, doesn't tell the whole story if combat flap settings are used. Hellcats and P-38s extended their flaps somewhat as they depressed to 8-10 degrees (?) adding square footage while altering air flow (changing lift co-efficient). P-40s may have been able to use a shallow flap setting but the flaps are split and the lower serface just hinges down.

Agree, the efficiency of the wing, which is I guess (?) CL Max, and the power also matter - and this would of course vary by altitude.

One other factor regarding rolling, both the A6M and the Bf 109 allegedly got very tight for roll at higher speeds (edit: Specifically for turning in one direction, i.e. due to torque which I think was right in both cases though I might be wrong. Luckily I'm not going into combat against one of these!). How much this mattered seems to be one of those endlessly debated things, but Allied pilots seemed to be aware of this by later in 1942 and relied on it to escape pursuit quite routinely. This was addressed somewhat in the A6M3 and later with the clipped wings. Trim tabs alleviated this in some US types.

The Ki-43 was limited in dive speed but apparently didn't have this locking up problem, and since Allied pilots often could not tell the difference between A6M and Ki-43, this was a problem in areas like New Guinea where they routinely encountered both types.

 

[Shortround6]

I don't really understand the relative advantages of split, full (per above)

I don't either.
The spit flaps cheap and easy to build and it was one of the first flaps used.
In the early to mid 30s they were just trying to slow the airplanes down and steepen the glide slope.
The P-36s had a wing loading of about 24lbs/sq ft and while they had stall speed of around 65-70mph, like a lot of these mid 30s monoplanes with large wings (6 sq ft less wing area than a Spitfire) they tended to float once they got into ground effect or with too shallow an approach. A lot of runways were small and they wanted to come in at a steeper angle with more drag to slow the plane down.

For the US they went from the Split flap on the P-26 Boeing to the double slotted Fowler Flap on the prototype A-26 in about 10 years with most of the other flap designs squeezed in-between. DC-3s used the split flap, Lockheed 14s used the single Fowler flap but.............

It was costly, when retracted you had 3 layers of wing skin, the upper, the flap upper and the lower, you had all the tracks instead of just hinges and you had all the cables/linkages.
For really high speed planes they wanted to get rid of the guide tracks because of drag.

 

[bf109xxl]

Unfortunately the Soviets didn't test P-38s...

The Soviets tested the P-38L (Serial No. 42-4384) in early 1947. It is not known whether the turn times were measured - the tests were discontinued due to the unavailability of 100-octane gasoline and the irrelevance of piston fighters.

 

[Steamed_Banana]

It seems like most of the Japanese 'maneuvering flaps' systems were fowler type, like on Ki-43, N1K2, Ki-84 etc.

 

[Steamed_Banana]

It was costly, when retracted you had 3 layers of wing skin, the upper, the flap upper and the lower, you had all the tracks instead of just hinges and you had all the cables/linkages.
For really high speed planes they wanted to get rid of the guide tracks because of drag.

yeah I remember noticing these when I made a Lockheed Hudson model a while back. Interesting point about the fowler flaps potentially taking up space inside the wing (and adding weight etc.)

 

[Admiral Beez]

It's a small plane, a lot smaller than I think people realize. Smaller wingspan than a Bf 109.

I've never seen a Ki-44 up close, but when I visited the Boeing museum in Seattle, I found the small size of the Ki-43 remarkable. The P-47 alongside seemed enormous.

eBay: Japanese airplanes and other hardware.

I visited the Museum of Flight in Seattle in August and was surprised to see a captured Nakajima Ki-43 Hayabusa (Oscar). Home | The Museum of Flight I was also surprised just how small and delicate the Oscar seemed beside the displays of Bf-109, Spitfire, Warhawk and especially the massive...

ww2aircraft.net

Mind, there are lots of compact single engined fighters. For example, both the Lavochkin La-5 and Bf 109E are quite a bit smaller (though heavier, with longer wingspans) than the Ki-44.

 

[Steamed_Banana]

I've never seen a Ki-44 up close, but when I visited the Boeing museum in Seattle, I found the small size of the Ki-43 remarkable. The P-47 alongside seemed enormous.

eBay: Japanese airplanes and other hardware.

I visited the Museum of Flight in Seattle in August and was surprised to see a captured Nakajima Ki-43 Hayabusa (Oscar). Home | The Museum of Flight I was also surprised just how small and delicate the Oscar seemed beside the displays of Bf-109, Spitfire, Warhawk and especially the massive...

ww2aircraft.net

Mind, there are lots of compact single engined fighters. For example, both the Lavochkin La-5 and Bf 109E are quite a bit smaller (though heavier, with longer wingspans) than the Ki-44.

I made 1/72 models of all major fighters and a lot of the tactical bombers and recon aircraft flying in 1940-43, and it's very interesting to see them side by side. The images in books don't give you the sense of scale or a full 3D view. The Ki-43 is indeed extremely slim and elegant. The Soviet fighters and the Bf 109, and the French and Italian fighters are all pretty small as well. The Spitfire is small except for it's big wing.

Some of the later Japanese fighters like the N1K1 are not so slim, nor are some of their bombers. I was surprised how huge the Swordfish is. But it's the P-47, Tempest, TBF / TBM, and Vultee Vengeance that all look so fat and oversized it's like they are at the wrong scale.

The Japanese Ki-46 recon plane is also very slim and small, as is the Soviet Pe-2 dive bomber. The French Bloch 693 is another really tiny one, as is the Westland Whirlwind.

 

[GregP]

If I don't misremeber, P-51 ailerons started out at ±10° travel and later could be rigged at ±10° or ±15° travel. The 15° setting resulted in better roll at all speeds.

The guy who is the authority on P-51s in here is Drgondog, having written several books on the aircraft.

 

[Steamed_Banana]

If I don't misremeber, P-51 ailerons started out at ±10° travel and later could be rigged at ±10° or ±15° travel. The 15° setting resulted in better roll at all speeds.

The guy who is the authority on P-51s in here is Drgondog, having written several books on the aircraft.

I'd be interested in his perspective. The roll for the P-51B on out seemed to be vastly improved, from pilot commentary and some stats that I can no longer find.

 

[Steamed_Banana]

Here's a Ki-44 from me:

View attachment 849711

I've seen a few of your drawings like this, they are really super cool, I love 'em. I think you could sell posters.

 

[Steamed_Banana]

Please see the section starting on page 37 about Allied opinion of the Ki-44.

FWIW

Eagledad

I've been slowly going through this, it's a really neat source, thanks for posting.

 

[GregP]

I've seen a few of your drawings like this, they are really super cool, I love 'em. I think you could sell posters.

Thanks! Appreciate it. I might try that. I was going to make place mats. But the cost didn't seem worth it without some actual interest and advertising it without product is worse.

Cheers to you.

Here's a K-i84 I did.