# J2M Raiden Jack vs. P-38J



## Soundbreaker Welch? (Jan 28, 2009)

Ok, maybe this could be interesting.

Who do you think could win?


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## drgondog (Jan 28, 2009)

Soundbreaker Welch? said:


> Ok, maybe this could be interesting.
> 
> Who do you think could win?



For any aircraft of near equal capability the outcome of a fight will depend on the tactical situation and pilot skill - same here.


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## Fokker D21 (Jan 28, 2009)

In comparison: P-38J vs J2M5

The P-38J has a speed advantage (402 mph versus 382) and is problaby more manoeuvrable at low speeds. The J2M has a climb rate advantage (3838 ft/m vs 3076 ft/m). The J2M5 has more firepower (4 x 20 mm vs 1 x 20 mm and 4 x .50) but the P38 has everything in the nose and the J2M in the wings. 

In a fight in the vertical I would say the J2M wins.
A low speed turning battle favors the P-38.
In a boom and zoom anyone can win.


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## delcyros (Feb 1, 2009)

I see it from a different perspective wrt low speed maneuverability.
A low speed turning battle is much to the taste of the J2M, a dive zoom favour the P-38´s significantly better zoom climb.


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## proton45 (Feb 2, 2009)

The P38 had the numbers...maybe not the type of answer you where looking for (lol), sorry...


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## fly boy (Feb 2, 2009)

i have never seen a jack


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## Soundbreaker Welch? (Feb 2, 2009)

Here's one, the only restored Raiden in a museum.


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## Pong (Mar 4, 2009)

Wow. Where is that museum?


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## Thorlifter (Mar 4, 2009)

drgondog said:


> For any *aircraft of near equal capability* the outcome of a fight will depend on the tactical situation and pilot skill - same here.



Agreed.


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## Ivan1GFP (Mar 4, 2009)

Both aircraft were seriously underrated for speed. The 371 mph typically quoted for a J2M was done with external tanks. TAIC test actually put the speed of this aircraft at 407 mph.

- Ivan.


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## Soundbreaker Welch? (Mar 4, 2009)

> Wow. Where is that museum?



I think it's at Chino Airport in California. Wish I could visit.


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## RabidAlien (Mar 6, 2009)

Agree with everyone who said "depends on pilot/situation"....but I voted for the P-38 just cuz I love that bird!


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## Sweb (Mar 7, 2009)

I read in a book - don't remember now - that the Japanese planes were in most ways superior to ours in performance. Robustness was our claim to fame and, of course, the Allies had some pretty remarkable machines with heavy firepower and range. The report was based upon Allied testing of captured planes that were returned to flying condition. One thing the Japanese could not do was produce the 100 octane fuels needed for their engines. The best they produced was 80. With 100 octane a couple types flew circles around all period Allied inventory during the Allied testing of them. The Hayate (Ki-84) in particular was the best of them. The Shiden came next. With 100 octane fuel the Ki-84 was faster than any Allied type, had an embarrassingly better ROC and with its combat flaps and airfoil out maneuvered all of its period counterparts and opponents. Because it was much lighter than its opponents it could literally firewall the throttle and take advantage in a fight or simply run away never to be caught by any other type except perhaps the H version of the P-51 which had some pretty good giddy-up. I remember reading it in one of the books I bought when building a 1/4 scale RC model of it. If the Japanese had the higher octane fuels the PTO might have turned out much differently than it did.


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## evangilder (Mar 7, 2009)

Sweb said:


> If the Japanese had the higher octane fuels the PTO might have turned out much differently than it did.



I highly doubt it. Prolong the war, maybe, but change the outcome? No.


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## FLYBOYJ (Mar 7, 2009)

There is no doubt that the Japanese produced some superior hardware however maintainability and interchangeability presented a problem though out the war and of course got worse later in the war. I think someone posted on here a narrative by a Japanese fighter pilot based in the Solomons complaining about the quality and maintainability of his aircraft.


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## Soundbreaker Welch? (Mar 7, 2009)

I think a P-47M could still beat the Hayate in speed. It could go over 500 miles per hour, one of the fastest fighters of the war.


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## Ivan1GFP (Mar 10, 2009)

I believe that there are quite a few misconceptions floating around here at the moment. I'll try to address a few (and hopefully get a little backup from those who have more actual involvement with aircraft than I do).

The typical Japanese fuel during WW2 was spec'd at 92 octane. They did not do as the Germans did and have a lower octane (more easily ignited) fuel for starting the engines. A test of fuel taken from captured Japanese army aircraft gave numbers around 96 octane. Either way, a few Japanese army fighters were equipped with fuel coolers presumably to reduce the possibility of detonation.

Fueling an aircraft with higher octane fuel doesn't necessarily improve performance. In most cases, it will probably perform worse without some timing adjustments to match the fuel. The higher octane fuel would allow higher compression or higher supercharger boost. Compression is not adjustable. Boost is, but I would hope that folks testing a captured foreign fighter would try to stick by whatever the manuals told them. From reading test reports, the TAIC folks did that. Also required with significantly higher octane fuels is a better ignition system. I doubt THAT would be redesigned to test a captured fighter.

The Japanese had a strange way of stating aircraft performance which tended to underestimate a good condition late model aircraft in the field. The US tests of the Ki-84 actually pretty much matched the specs the Japanese arrived at in one of their less commonly quoted documents. Even then, 425 to 430 mph at 20,000 feet is not blazing fast for a fighter at the end of the war.

Regarding climb performance and maneuverability, I believe that their climb performance was very good down low, but deteriorated badly as altitude increased. Maneuverability at low to medium speeds was good, but not necessarily as good at high speeds.

Also, the descriptions I just gave are of aircraft at their peak performance. The Japanese had lots of trouble maintaining their manufacturing quality. I believe that is why planes such as the Ki-100 were so well rated. The peak numbers aren't great, but the aircraft is much more likely to perform as claimed by the manufacturer.

Another factor is that production numbers are generally pretty low. Even major types such as the J2M and N1K only had a few hundred or a thousand produced.

Keep in mind that this is basically my own interpretation after doing a LOT of reading, so please feel free to argue any points.

- Ivan.


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## Timppa (Mar 10, 2009)

Couple of threads from other discussion forums about late Japanese fighter performance:

Ki-84 report...USAAF test...

ki84 speed????

Busa from this latter thread is Japanese, he dug out some info that was generally not known.


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## Ivan1GFP (Mar 10, 2009)

Hi Timppa,

The Japanese language table posted by 200th Sakagawa is actually what I am quoting from. For folks who are interested, I recommend you download the image and print it out full page. About 2/3 of the way down on the page, there is a line with maximum speeds. The third column quotes 689 kph (6100 meters) or 428 mph which is pretty close to what the US got with their test aircraft.

I asked my wife to translate quite a lot of this page for me some time back. A lot of the numbers are recognisable and she gave me her interpretations before I told her what I thought they were. She isn't Japanese, but a lot of the writing is in Kanji which is about the same as written Chinese which she can read.

- Ivan.


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## Pong (Mar 11, 2009)

I agree with Evan. Even if they had the high octane fuel, there were more trained pilots in the allied carrier force. When the Battle of Santa Cruz happened, that was it. 400 of the 700 pilots that fought in Pearl Harbor were KIA. Yeah, the Japanese had some advanced planes but there were hardly any properly trained pilots to fly them.


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## davebender (Mar 11, 2009)

If Japan has more and better fuel then they will have more and better pilot training. The same holds true for Germany.


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## FLYBOYJ (Mar 11, 2009)

davebender said:


> If Japan has more and better fuel then they will have more and better pilot training. The same holds true for Germany.


How do you rationalize that? Just because you have better or more fuel doesn't mean you're going to have better trained pilots. It depends how new pilots are being taught to fly and what type of combat training they are receiving. Time in the air is a big factor but if the pilots aren't receiving training to meet the combat need, then all the fuel in the world isn't going to help.


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## Ivan1GFP (Mar 15, 2009)

Hi folks,

For what it's worth, the Germans at least typically used fuel that was quite high in octane. Their C3 fuel was nominally only 96 or 100 octane, but was much superior to the US 100 octane fuel. Look for the flight testing of FW 190 EB-104 - 140 grade fuel was used because it was equivalent to the German fuel. It is superior to 130 grade (100 octane). The numbers vary a little from what we expect because there are two octane ratings for a given fuel (calculated for running at rich and lean mixtures). There is also the question of whether the numbers being quoted are Research or Motor octane.

Consider also that the power output of an engine isn't going to change much if you put in higher octane fuel unless you are going to change the ignition timing or supercharger boost settings. 

Yes, I know that most cars don't have superchargers, but has anyone here noticed performance improvements by using a higher grade of pump gas? I have a car that NEEDS premium, but my other car pretty much drives the same with whatever I put in. Consider that these are modern cars with computers that probably retard timing based on sensors detecting detonation and that computer controls are much more sophisticated than mechanical controls from the 1940's.

- Ivan.


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## HoHun (Apr 16, 2009)

Hi Welch,

>Who do you think could win?

Here is a comparison based on TAIC data for the J2M2. Note that the engine rating given for example here ...

The Pacific War Online Encyclopedia: J2M "Jack", Japanese Fighter

... is a bit lower than TAIC MIL, which would result in reduced climb and turn rates (assuming that the 650 km/h @ 6.2 km top speed was valid for whatever engine was installed).

Regards,

Henning (HoHun)


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## Soundbreaker Welch? (Apr 16, 2009)

Thanks! It looks like the Lightning does pretty well agains't the Jack in some areas.


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