Jack vs. Tojo - Which was better? Why?

[DarrenW]

Darren, sometimes "good" is a good thing.

Lol yes you're absolutely right Corsning, especially when one of those ratings could have easily been considered "bad". Oh well. So I guess that the Japanese, unlike the Americans, didn't know a "good" thing when they saw it and decided to go with other designs instead....to their determent of course.

 

[DarrenW]

Not sure where you are getting all your objections, but the only ones that seen true to me are engine and landing gear problems.

My sources are:

J2M Raiden and N1K1/2 Shiden/Shiden-Kai Aces (Izawa/Holmes) and Imperial Japanese Navy Aces 1937-45 (Sakaida)

 

[DarrenW]

It had two 20 mm cannons and two 30-cal MG, which is effective enough considering the number of Allied aircraft shot down by that exact combination, which is ... like ... almost all of them.

I didn't bring up armament but now that you have do you happen to have statistics concerning the actual victory count for the J2M series using these cannons?

 

[GregP]

Then some source is very wrong. 138 mph is about 119 knots and that is Lockheed T-33 speeds for landing, not Radien speeds. Ditto the rest. What you are saying just isn't right.

 

[DarrenW]

Then some source is very wrong. 138 mph is about 119 knots and that is Lockheed T-33 speeds for landing, not Radien speeds. Ditto the rest. What you are saying just isn't right.

I never flew the airplane so all I have is my source material to go by. Much of what is in these books are eyewitness testimonials which were given to the respective author. If any of the material is incorrect than it can most likely be traced back to a Japanese pilot or ground crew member.

If you're saying it had a landing speed similar to a WWII carrier aircraft then who am I to disagree with you...but feel free to throw another red X my way if it makes you feel any better.

 

[DarrenW]

The J2M-3 (most-produced: 435 built) hit 370 mph and had a 360° turn time of 18 seconds (speed not specified), which is right in there with a Yak-3, widely regarded as the best turner in modern WWII fighters. The J2M-1 (8 built) turned in 16 sec and the J2M-2 (141 built) turned in 17 seconds. A Hellcat could not match 18 seconds and neither could a Mustang. Really. A Messerschmitt Bf 109G was 22.6 - 22.8 sec. A Mustang I was 23 sec.

What is your source for these numbers? I'm not trying to be difficult, just interested is all.

 

[Shortround6]

Just throwing this out there.
Sometimes stalling speed, landing speed and approach speed get confused or badly translated. Stalling speed especially is affected by weight but so are the other two.

P-40D/E had an approach speed of 90mph at 8400lbs even though stall speed was in the 70s.
Throw in a bad translation that confuses mph with knots and we get 166,6kph and turn that back to MPH and we get an approach speed of 103 mph

Or just bad proof reading/typo.

 

[DarrenW]

Just throwing this out there.
Sometimes stalling speed, landing speed and approach speed get confused or badly translated. Stalling speed especially is affected by weight but so are the other two.

P-40D/E had an approach speed of 90mph at 8400lbs even though stall speed was in the 70s.
Throw in a bad translation that confuses mph with knots and we get 166,6kph and turn that back to MPH and we get an approach speed of 103 mph

Or just bad proof reading/typo.

Excellent observation thanks for the insight.

 

[taly01]

The Kasei 20 series engine was water injected and there was "rough" running troubles getting the water injection right on both G4M and J2M, it is possible the frequency of the rough engine running matched critical vibration speeds of J2M propellor/shaft, until they changed the prop which removed the failure cause, but not roughness.

Now enter the designer who wants a prop to generate more cooling flow near its hub and dissipate more horsepower outside the cowl diameter without increasing blade count or overall diameter. ..........................It's become a stiff board with a hinge at one end, concentrating the bending action at the root and creating a huge metal fatigue issue.

This reminds me of the confusion I have over cuffed propellors, I assume they were seperate to the prop blades so they could be sized for engine cooling requirements,

but then I see pictures of P-51 with cuffed blades? What cooling is needed there!

 

[GregP]

Hi DarrenW,

A red X is not a negative, it means "I disagree." Agreement and disagreement are the basis of discussion.

There weren't many WWII carrier planes with a landing speed of 81 mph. Most were slower.

I have not posted any "flame attempts" or said anything about you personally. The specs on the J2M I can find simply don't match what you've posted and I have the rather unique opportunity to see one live anytime I want to. Perhaps that makes a difference to me, but the J2M-3 seems like a pretty good fighter from all I can find, and that is backed up by a Planes of Fame Museum member from Japan.

I have no dog in this hunt. I just like the Raiden and you don't seem to. There is absolutely nothing wrong with either opinion.

Let's try a calculation. A basic wings-level stall speed should be about: Vs = 17.2 * square root (W / (CLmax * sigma * S)), where Vs = stall speed in knots, W = weight, CL max = max lift coefficient, sigma = altitude density ratio, and S = wing area (sq ft). Let's try sea level, 7,077 lbs combat weight, 215.8 sq ft wing area, sigma = 1 at sea level ... and I'll go with CL max = 1.5 for a decent WWII fighter wing average. It could be better. Calculated stall speed without flaps using the above formula is 80.4 knots TAS, making the flaps down stall speed of 81 mph in the specs look pretty darned close. And, it's a far cry from 138 mph. Let's say the flaps aren't very good and drop the stall speed by only 5 knots. That puts it at 75.4 knots or 86.7 mph. Considering I don't have the real CL max, I'd believe the 81 mph any day. If the real CL max goes to something like 1.65, the flaps-up stall speed calculates to 76.7 knots. The real number SHOULD be somewhere around 1.45 - 1.65, I can't say where it actually falls.

The J2M is rather widely regarded as a pretty good fighter when it was operating correctly.

We don't have to agree on the Raiden. There is only one left, and it isn't flying at this time. So, we just disagree on its merits. No biggie. Cheers to you.

Several sources: I can find the wing area at: Mitsubishi J2M Raiden (Jack) Info or any number of websites. Try: Mitsubishi J2M Raiden (Thunderbolt) 'Jack' , too, for number produced and Mitsubishi J2M Raiden - Specifications - Technical Data / Description, too. I also have a book, "Japanese Aircraft Performance and Characteristics," written by Ed Maloney, founder of the Planes of Fame. His quoted specs come straight from TAIC. I have other books, but they say the same things.

Cheers again.

 

[DarrenW]

Hi DarrenW,

A red X is not a negative, it means "I disagree." Agreement and disagreement are the basis of discussion.

There weren't many WWII carrier planes with a landing speed of 81 mph. Most were slower.

I have not posted any "flame attempts" or said anything about you personally. The specs on the J2M I can find simply don't match what you've posted and I have the rather unique opportunity to see one live anytime I want to. Perhaps that makes a difference to me, but the J2M-3 seems like a pretty good fighter from all I can find, and that is backed up by a Planes of Fame Museum member from Japan.

I have no dog in this hunt. I just like the Raiden and you don't seem to. There is absolutely nothing wrong with either opinion.

Let's try a calculation. A basic wings-level stall speed should be about: Vs = 17.2 * square root (W / (CLmax * sigma * S)), where Vs = stall speed in knots, W = weight, CL max = max lift coefficient, sigma = altitude density ratio, and S = wing area (sq ft). Let's try sea level, 7,077 lbs combat weight, 215.8 sq ft wing area, sigma = 1 at sea level ... and I'll go with CL max = 1.5 for a decent WWII fighter wing average. It could be better. Calculated stall speed without flaps using the above formula is 80.4 knots TAS, making the flaps down stall speed of 81 mph in the specs look pretty darned close. And, it's a far cry from 138 mph. Let's say the flaps aren't very good and drop the stall speed by only 5 knots. That puts it at 75.4 knots or 86.7 mph. Considering I don't have the real CL max, I'd believe the 81 mph any day. If the real CL max goes to something like 1.65, the flaps-up stall speed calculates to 76.7 knots. The real number SHOULD be somewhere around 1.45 - 1.65, I can't say where it actually falls.

The J2M is rather widely regarded as a pretty good fighter when it was operating correctly.

We don't have to agree on the Raiden. There is only one left, and it isn't flying at this time. So, we just disagree on its merits. No biggie. Cheers to you.

Several sources: I can find the wing area at: Mitsubishi J2M Raiden (Jack) Info or any number of websites. Try: Mitsubishi J2M Raiden (Thunderbolt) 'Jack' , too, for number produced and Mitsubishi J2M Raiden - Specifications - Technical Data / Description, too. I also have a book, "Japanese Aircraft Performance and Characteristics," written by Ed Maloney, founder of the Planes of Fame. His quoted specs come straight from TAIC. I have other books, but they say the same things.

Cheers again.

Sorry Greg, I didn't mean to turn this into an emotional debate for you. The points I've made have nothing to do with liking or not liking the aircraft. I find it fun to talk about old airplanes and that's really the size of it. I have my sources and you have yours and obviously they don't agree. We can leave it at that.

Lastly, you seem to be hung up on stall speed but Shortround pretty much explained some very plausible reasons for the discrepancy. I'm satisfied if you are.

Cheers to you as well.....

 

[Ivan1GFP]

Besides a better than average climb rate at medium altitudes, what was so "impressive" about it's performance? The J2M was the least favored of the late-war Japanese fighters, with many pilots commenting that it lacked the handling and maneuverability to successfully dogfight with a Mustang or Hellcat. They also disliked the very high landing speed (138 mph) and poor forward visibility. Pilots had to be proficient at dead sticking the plane as engines seized so often. When given the choice some even reverted back to the older but trusty Zero. Only a seasoned pilot like the eccentric Sadaaki Akamatsu had any words of praise for it.

Hello DarrenW,

The problem with some of these pilot opinions is that they may be the result of the "Culture" of how they were trained.
If you have the book about Mitsubishi Zero by Robert Mikesh (Motorbooks), it gives a pretty good account of some discussion that went into the design requirements for the A6M:
Two very experienced fighter pilots had vastly differing views on requirements for speed versus maneuverability.
Genda preferred Maneuverability.
Shibata preferred Speed and argued that pilot training could compensate for shortcomings in maneuverability.
Genda won the argument and we know how short the effective life span of the resulting A6M design was as a result.
By the end of the war, Shibata was proven correct, but there were probably still quite a few pilots left who had the same opinion as Genda did.

When compared to the A6M or Ki 43 in a low speed fight, nothing else is going to be that close.
Keep in mind that the Japanese also had the opportunity to test the Me 109E and the FW 190A and didn't like either one.

How would these same Japanese pilots have liked the Corsair, Yak-3, or La-5FN? Does it mean that those were inferior fighters to the A6M or just that the pilots doing the evaluations were not accustomed to the style of fighting that those aeroplanes required?

- Ivan.

 

[Ivan1GFP]

Just throwing this out there.
Sometimes stalling speed, landing speed and approach speed get confused or badly translated. Stalling speed especially is affected by weight but so are the other two.
.......
Or just bad proof reading/typo.

Hello Shortround6,

I believe we ran into the same problem a while back in a translated manual for the Ki 43 in which speeds in KPH were mistaken for MPH with some resulting numbers that looked OK at a glance but made no sense in physics.

- Ivan.

 

[GregP]

Cheers DarrenW. It's all good.

I'm not hung up on stall speed. It is just tough to wrap my head around a 7,000 pound fighter supposed to have a landing speed higher than a B-26 Marauder.

I surely wish we had more voluminous information about Japanese warbirds. Alas, we seem to have to make due with a few bits of information that vary among sources, sometimes rather widely. I like the late-war Japanese fighters including the Ki-84, J2M, N1K, and Ki-100. I could include the Ki-44, too. They aren't collectively especially fast but climbed well and were enough to give most Allied fighters a run for their money.

Of these, the Raiden would seem to have the most quality issues.

 

[DarrenW]

Hello DarrenW,

The problem with some of these pilot opinions is that they may be the result of the "Culture" of how they were trained.
If you have the book about Mitsubishi Zero by Robert Mikesh (Motorbooks), it gives a pretty good account of some discussion that went into the design requirements for the A6M:
Two very experienced fighter pilots had vastly differing views on requirements for speed versus maneuverability.
Genda preferred Maneuverability.
Shibata preferred Speed and argued that pilot training could compensate for shortcomings in maneuverability.
Genda won the argument and we know how short the effective life span of the resulting A6M design was as a result.
By the end of the war, Shibata was proven correct, but there were probably still quite a few pilots left who had the same opinion as Genda did.

When compared to the A6M or Ki 43 in a low speed fight, nothing else is going to be that close.
Keep in mind that the Japanese also had the opportunity to test the Me 109E and the FW 190A and didn't like either one.

How would these same Japanese pilots have liked the Corsair, Yak-3, or La-5FN? Does it mean that those were inferior fighters to the A6M or just that the pilots doing the evaluations were not accustomed to the style of fighting that those aeroplanes required?

- Ivan.

True, but it's no coincidence that the IJNAF ultimately chose the Shiden/Shiden-Kai series as their primary interceptor-fighter. In that decision the opinions of front-line pilots/ground crews were relied heavily upon, probably just as much as the technical side of the equation. My sources conclude that pilots continually complained about it's lack of performance, which only got worse as weight increased with the addition of both heavier armor and armament.

 

[DarrenW]

Cheers DarrenW. It's all good.

I'm not hung up on stall speed. It is just tough to wrap my head around a 7,000 pound fighter supposed to have a landing speed higher than a B-26 Marauder.

I surely wich we had more voluminous information about Japanese warbirds. Alas, we seem to have to make due with a few bits of information that vary among sources, sometimes rather widely. I like the late-war Japanese fighters including the Ki-84, J2M, N1K, and Ki-100. I could include the Ki-44, too. They aren't collectively especially fast but climbed well and were enough to give most Allied fighters a run for their money.

Of these, the Raiden would seem to have the most quality issues.

Good, I'm glad we have come to a sense of understanding.

On another note there is something related to the J2M3 at Planes of Fame that has me puzzled. Why are the tail markings consistent with a Raiden assigned to 302nd Kokutai, while the fuselage is adorned with lightning bolts that are often associated with the 352nd Kokutai? Is it supposed to be a hybrid of sorts in order to represent both units?

 

[Ivan1GFP]

True, but it's no coincidence that the IJNAF ultimately chose the Shiden/Shiden-Kai series as their primary interceptor-fighter. In that decision the opinions of front-line pilots/ground crews were relied heavily upon, probably just as much as the technical side of the equation. My sources conclude that pilots continually complained about it's lack of performance, which only got worse as weight increased with the addition of both heavier armor and armament.

Hello DarrenW,

I believe the choice of the N1K2-J over J2M was for different reasons and is a different argument altogether.
Assuming a J2M was in good running order, it was a pretty good interceptor. It was not a good general purpose fighter because it had no range.
As for weight increases with additional armour and armament there were obviously differences between J2M3 and earlier models, but there really weren't any other significant changes during the rather short production run other than attempts with installing different variations of the Kasei engine with and without turbochargers. The only really significant armament change between J2M2 and J2M3 with the cowl MG being replaced by an additional pair of wing cannon.

The preference of Japanese pilots for N1K2 over J2M probably also goes back to the culture situation I described earlier though in this case the overall straight line performance wasn't that different. They just aren't going to like a fighter that doesn't maneuver as well.
The quality of N1K2 versus J2M wasn't really the subject of this thread in any case. The bottom line was that NEITHER aircraft was reliable in service though both had great potential if everything was working correctly which usually was not the case.

- Ivan.

 

[GregP]

Hi DarrenW,

I do not know about the chosen paint scheme for our J2M-3, but most of our aircraft are painted in the schemes of actual combat aircraft. Next time I see him, I'll ask John Maloney. He painted it.

 

[DarrenW]

I believe the choice of the N1K2-J over J2M was for different reasons...

The bottom line was that NEITHER aircraft was reliable in service though both had great potential if everything was working correctly which usually was not the case.

Hi Ivan,

I disagree with the first statement and agree with the second, but as you stated the topic of the thread doesn't include the Kawanishi fighter so there's no need to discuss it any further here.

 

[cherry blossom]

I have spent some time reading Wikipedia and I wondered if anyone else has noticed that the designs of the Ki-44 and the J2M represent different philosophies. The Ki-44 is rather typical of its generation of Japanese fighters in being very lightly constructed and in lacking armour. However, if we want to find fighters with a similar wing, our best comparisons are the Yak-3, wingspan 9.2 m (30 ft 2 in) and wing area 14.85 m2 (159.8 sq ft), and the original prototypes of the Fw 190, wingspan 9.5 m (31 ft 2 in) and wing area 15.0 m2 (161 sq ft). The Ki-44 II had a wingspan of 9.45 m (31 ft 0 in) and a wing area of 15 m2 (160 sq ft). The Ki-44 with an empty weight of 2,106 kg (4,643 lb) is even lighter than the Yak 3 which has an empty weight of 2,346 kg (5,172 lb). The Fw 190 was designed as a "cavalry horse" and even the v1 weighed 2,768 kg (6,103 lb) whilst an A3 of 1942 weighed 2,900 kg (6,393 lb) empty. As expected from the weights, the Ki-44 climbs best, reaching 5,000 m (16,404 ft) in 4 minutes 17 seconds, whilst Yak-3 can climb to 5,000 m (16,404 ft) in 4 minutes 30 seconds. The Fw 190A3 presumably using a derated engine in November 1942 (just after the Ki-44 II had entered service) takes about 6 minutes to reach 5,000 m http://www.wwiiaircraftperformance.org/fw190/fw190-a3-sheet-26-11-42.jpg as does the La-5.

If we look at maximum speeds, the RAE measurement of Faber's Fw 190A3 with a derated engine was 375 mph at 18,000 ft or an estimated 392 mph had the BWM been fully rated whilst Wikipedia gives the speed of the Ki-44 II as 605 km/h (376 mph, 327 kn) at 5,200 m (17,060 ft), presumably at "military" rating. The Yak-3's smaller and slimmer fuselage gives it a maximum speed of 646 km/h (401 mph, 349 kn) at 4,100 m (13,451 ft) but, of course, nearly two years later.

My tentative conclusion is that the Ki-44 could have been a terrifying if fragile opponent at low to medium altitude and that the USAAF over New Guinea was lucky that their opponents did not deploy it. Of course, the range was inferior to that of the Ki-43 and the Ki-61 and it is possible that Ki-44 had defects such as low Vne or a low rate of roll which have not been mentioned so far in this thread. However, there is no obvious reason why it should not roll rapidly and its acceleration should be the best in the world in late 1942.

By contrast, the J2M seems a typical non-Japanese fighter. The wing area, 20.05 m2 (215.8 sq ft), is almost the same as the Ki-61 or Ki-100 and falls in the middle of the Italian 5 Series being just less than the Re 205's 20.4 m2 (220 sq ft). The empty weight of 2,839 kg (6,259 lb) is heavier than any of those aircraft and close to that of the Fw 190 A3. The larger wing means that the J2M3 climbs to 6,000 m (19,685 ft) in 6 minutes 14 seconds compared to 7.6 minutes for the Fw 190 A3 (note that the J2M3's contemporary the Fw 190 A8 climbed slower due to extra armament and armour and the Raiden could even beat the Fw 190 D9 to 6,000 m). In the thread N1K2-J Shiden-Kai Performance Laurelix argues convincingly that a Shiden could climb quicker if everything was working and this probably caused the IJNAF to prefer it. However, the Shiden's Homare didn't always give the expected power and thus the J2M was the best Navy fighter for attacking B-29s at high altitude.