N1K2-J Shiden-Kai Performance

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taly01 said:
I believe I read a US informal test of N1K1-J in Philippines and they said it got close to 400mph (before it was written off by landing gear collapsed).
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Was this speed obtained in level flight? According to a post-war interrogation of Minoru Genda the N1K2 had a nasty habit of having it's landing gear "fall apart" when diving at 420 mph or more....
 
The N1K1-J seems to have been 360mph in the US test, and the landing gear collapsed upon landing in a crosswind.
I found the thread here N1K1-J Shinden Model 11 contains a linked magazine article of the report. The original test report is floating around on the web somewhere.

Japanese sources are scathing about the N1K1-J poor speed for all combat versions and 343Ku mostly used them for training and recon after they got the 2-J, the N1K2-J test pilot claimed 644kph (400.2 mph).

It depends what Laurelix is trying to model, wartime performance or best case performance. I think these are pretty close.

N1K1-J w/gondola cannon
583km/h (362mph) at >6000m - MIL
607km/h (377mph) at <6000m - WEP

N1K2-J
611km/h (380mph) at >6000m - MIL
637km/h (396mph) at <6000m - WEP

I might try to make these Flight Models for il2:1946 and see if the same engine really can be used for both for these performances!
 
taly01 said:
The N1K1-J seems to have been 360mph in the US test,
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I read the report you provided, thank you for posting it.

It says that the aircraft was tested from a stall up to 360 mph indicated. This is a bit ambiguous as it doesn't say whether it was achieved in level flight or a dive, and without a stated altitude or an airspeed indicator correction factor it's hard to say with any assurance what the true airspeed really was.

And if those figures you present are "best case performance" then I am in complete agreement with you. I never claimed that the Shiden-Kai couldn't match the level speed of the Hellcat IF it were in "factory working order" and maintained/operated as specified by the manufacturer. The problem is that this wasn't the case late in the war for all the reasons that I have explained up to this point.

I feel it's safe to say that, just like with German aircraft during this same period, it would be logical to reduce maximum speed by 20-30 mph (30-50 km/h) from accepted and verified performance figures for the aircraft in question.
 
Excellent post, great info and I think your dissemination of what happened is pretty much spot on. I was always suspect of the claims about the latest IJN/IJA fighters knocking down Hellcats (and Corsairs) at will, sounded like a lot of bollocks to me. I've seen other boards where apparently all the N1K2 had to do was show up and droves of F6F's simply fell from the skies against this mighty giant killer.

I shudder to think, well, an N1K2 pilot might shudder to think what would happen if they ran into the latest P-47N or P-51H, which people tend to forget in their breathless "what if" comparisons, is what they'd be running into. Had the war continued into 1946 those were the USAAF fighters they should be compared with, not to mention the P-80.
 
I was always suspect of the claims about the latest IJN/IJA fighters knocking down Hellcats (and Corsairs) at will,
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I think people translated WW2 era Japanese reports as gospel when they were wartime newspaper propaganda. The actual amazing thing about 1945 is that a large Japanese fighter sweep may have 50 planes but then find themselves against some 400 US ones, often it was more like 20 vs 200.
 

Yes, it would have been even a worse blood bath for the Japanese. Thankfully for both sides the war ended before such events took place.

And people tend to forget that most American fighters flying over Japan in 1945 were concentrating on the destruction of airfields for the expected invasion so they normally weren't flying at heights conducive for the element of surprise (a tactic necessary when entering a dogfight). The Japanese on the other hand were waiting over their own territory and could vector on the Americans by means of radar, coast watchers, and reconnaissance aircraft. They most surely had the tactical advantage but still suffered great losses in the end.
 
Peter Gunn said:
Eye of the beholder I guess, its looks don't do much for me, reminiscent of the svelte A6M after one too many wagyu steaks. It's not ugly but not (to me) beautiful.

Again, just my personal opinion on its looks, not performance.
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Yeah to me it just has that look of a kind of flying muscle car, while being reasonably elegant (compared to say, a P-47)
 
taly01 said:
The actual amazing thing about 1945 is that a large Japanese fighter sweep may have 50 planes but then find themselves against some 400 US ones, often it was more like 20 vs 200.
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While this definitely was the case when one counts the total numbers of US warplanes participating in fighter sweeps throughout any given day, individual units of 12-24 aircraft where often tasked with neutralizing Japanese air resistance in localized areas solely on their own or in tandem with another. There were a multitude air bases throughout mainland Japan that could respond locally to attacks at any time with a couple dozen fighters or more. For instance, the 343rd Kokutai were able to muster 40 'Georges' out of a total of 63 airborne before attacking 20 Hellcats of VBF-17 on the 19th of March. Outnumbered two-to-one the Americans brought down four of the enemy while losing six in return. The outcome for the rest of the day was fully in favor of F6F pilots, with eight more verified shoot downs and no losses. The F4U units involved with the 343rd broke even with three victories and three losses to Shiden-Kais. All of these results have been cross referenced and verified.
 
WHY does it matter ????? The war is over 75 years ago !!!!
 
taly01 said:
There are lots of computer flight simulators that have these planes, some are pay-to-play online competitive games so people like to have "real" plane performance.
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They do and not just the Theoretical on paper or from one off prototypes that had exceptional performance compared to airframes used in service.
 
Really fascinating this reapraisal of Shiden's speed.

I'm very curious, on the N1K1-J, by how much did the gondolas reduced the speed? Why they went for that solution is beyond me. And also that horrible "wart" on the lower right of the nose, i saw it described as a fuel cooler or oil cooler, how much would that cut into speed too?

There is a later N1K1-Jb (i think) variant with all 4 guns in the wing, very curious what kind of speed would it have compared to the initial model?
 
I came across an interesting comment on a YouTube video which mentioned that the mismatch between top speed of IJN aircraft is because of a translation error. According to this comment, the IJN reported all its top speed estimates in knots, which was standard among some naval forces (knots were once used to gauge ship speeds by counting knots on a rope). A French interpreter recorded the knots as MPH.

The commentor said that his source is from archival content contained within the Pacific Theatre Interrogation Reports (held by the Library of Congress). It is significant because this report was used by other "primary" sources such as Francillon and has informed all post-war scholarship on the N1K's performance.
 

Hate to rain on this parade, but...
Why on earth will US military give such an important job to a Frenchman?? And one person to translate all docs dealing with capabilities of Japanese A/C? Francillion used a host of sources for his book on Japanese A/C. .There is a lot of Japanese tables that post modest performance numbers for their latest aircraft.
As they say - extraordinary claims require extraordinary evidence - it was easy even in 2000 to take photos of original docs and spread them via publications. Hopefully the commentator is a more ... straightforward person than the one that claimed that he saw docs saying that Napier Sabre was good for 5000 HP, but, alas, RR made sure that such docs disappear.

I do hope I'll be proved wrong.
 
I'm also very skeptical of the commentor's claim. But there are a few things in it that explain the odd mismatch between IJA and IJN aircraft top speeds.

Regarding your claim that extraordinary claims require extraordinary evidence: we are not dealing with an extraordinary claim. Low IJN top speeds have puzzled researchers like ourselves for years. None of the explanations handle well under scrutiny. Just because someone considers a claim to be extraordinary doesn't mean that the burden of proof is now higher.

But in this case, because the claim is sourced, it's only needed to find the original document in the Library of Congress and then read it for ourselves. It might turn out that the documents or archival footage do not contain what the commentor claims. However, this appears to be a falsifiable claim. There is somewhere recorded tape, video, or documents that can simply read for ourselves and find out the truth.

Regarding the translator, you make a good point. In this case, the commentor said that it was a translator who spoke French (possibly English), and Japanese and they were involved in the interrogations of Japanese ground crew during the TAIC interviews with Japanese groundcrew. However, as you say, there were 6,000+ interpreters who spoke Japanese and English fluently, working for the US military. There would have been no reason to use a French interpreter unless they used diplomatic staff for political reasons.

There are other issues with the claim as well. For starters, the N1K2's top speed was recorded as 369 MPH. If this were knots, it would be completely outside what other sources have claimed. But the commentor claimed that the actual claim was 360 knots for the N1K2 in interrogation. But as all these things are easily scrutinized on examination, it's just a matter of someone getting access to those documents. Unfortunately, the Library of Congress requires people to register in person to access their documents.
 
Just a reminder that N1K2-J max speed wasn't 369mph (595kph)

Someone should just delete Francillon N1K page already…

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N1K1-J estimate for max speed, the version without underwing gondola's was estimated to have 657km/h at 6000m according to TAIC and since both planes have the same engine and more or less same frontal profile except the fact the wings center mounted, the drag should be roughly similar. Obviously the main proof is in the opening post for the N1K2-J.
 
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