Jack vs. Tojo - Which was better? Why?

[tomo pauk]

Well, if you are satisfied with a 350-360mph aircraft in 1942/43 you might have gotten it (barely). If you are trying for the 370mph airplane the things are harder.

Or will the A6M with the 1942 Kinsei engine be fast enough? Or do you have to wait for 1943?

Seems like the Ki-46-III was flying with water-injected Ha-112-II (a member of the Kinsei family) in December of 1942 as prototype. Talk mid-1943 in-service, 360-370 mph?
For 1941, the Kinsei 50 series were good for 1100 CV at 6200m ft, as installed eg. on the G3M3 bomber. Sakae 21 on A6M3 in 1941 (1st flight) was good for 980 Cv at 6000 ft, providing the max speed of 545 km/h (339 mph).
We'd possibly gotten at ~345 mph with the Kinsei 50s, and a few mph more with deletion of hook etc?
In retrospect, a Zero with the water-injected Kinsei 60 engines in 1943 was no worse than what the IJN had 1944, even if such the Zero is only land-based.

Another engine option is Ha-41, yes, the engine from the competition, as it was the case with Sakae on the Zero.

Just opened my new book on Japanese aero engines and it is missing 4 pages right at the end of the Mitsubishi chapter on the pacific war period (all the Mitsubishi engines we are interested in) all but one of the data tables for the Mitsubishi engines.

Bummer
The translated book on the Mitsubishi engines from this forum (thank you, Shinpachi ), as well as the TAIC manual from here are really great assets IMO.

The Japanese were short on power and tried to substitute aerodynamic tricks
Some planes could get away with it, some gave more troubles with poor vision or cooling or whatever.

No tricks can be seen on that picture, just a job well done
Japanese engines have had good power, reliability and low weight, but most of these went into bombers, not fighters.
They also have had hard time figuring out that 1000 HP engines will not cut it, and have persisted for too long on eg. making Zuiseis instead of focusing on the other 2-3 more powerful engines at Mistsubishi (Kinsei, Kasei, as well as Ha-42 of 2000 HP). Going with two licences for the DB 601A was another grave mistake, both Kawasaki and Aichi should've been exclusively making radial engines under licence. Another mistake was ending the Ha-109 engine production.
The J2M with as-is Kasei (ie. no extension shaft) was another missed opportunity.

 

[Reluctant Poster]

A major strategic failing of the IJN was its insistence that all its aircraft have supremely long range. Zeroes (or really any of their carrier aircraft) often doubled as scout aircraft (despite having horrible radios, which limited their effectiveness). This also gave the IJN the advantage of being able to conduct attacks beyond the strike radius of enemy carriers.

The blunder here was that the IJN brass didn't want any of their early-to-mid war frontline aircraft to have even the lowest grade of self-sealing fuel tank, despite objections from designers. The B6N series, for example, could do 2,400 miles as a scout or 1,400 with a full bomb load. It's borderline insane that their most shot-up bombers lacked self-sealing fuel tanks.

As such, the Imperial high command didn't assign much value to carrier-based interceptors with short ranges as they couldn't pull double duty as scouts. This overemphasis on offense and strike power would cost them at Midway, although it also aided the IJN's tactical victories throughout '42 and part of '43.

A Raiden-like interceptor at Midway would have been exceptionally effective at intercepting dive bombers. Except for one thing: its laminar wing would have made for longer take-offs and landings. Which means a Raiden may only have been able to operate from the largest of carriers, if at all. The Raiden's stall speed, with flaps, was something like 92 MPH. A Zero, in comparison, was something like 65 MPH (according to TAIC).
AFAIK, the only "laminar" airfoil to see service during WW2 was on the Japanese C6N Saiun/Myrt. So there may have been some issue adapting low-flow wings to carrier craft.

Getting back to the Tojo-Jack comparison, the Tojo's stall speed (with its non-laminar wing) was around 93 MPH, according to Martin Ferkl. However, other sources list it as being around 85 MPH. I think both could be correct and the higher limit is flaps up. Overall, the Tojo's size and lower landing speed would have made it a better fit for carrier operations.

The problem with the Zero at Midway wasn't its performance. It had for its era an exceptional rate of climb which is the key parameter. It failed due to a complete lack of a fighter direction system. The USN proved during 1942 that, while their fighter direction system didn't perform up to expectations, an underperforming fighter direction system was much, much better than none at all.

 

[Thumpalumpacus]

The problem with the Zero at Midway wasn't its performance. It had for its era an exceptional rate of climb which is the key parameter. It failed due to a complete lack of a fighter direction system. The USN proved during 1942 that, while their fighter direction system didn't perform up to expectations, an underperforming fighter direction system was much, much better than none at all.

IIRC, at Midway fighter direction consisted of screening cruisers firing in the direction of an incoming wave, at points even using main-battery guns. About as inefficient as one could imagine.

Hell, if nothing else, orbit one fighter or Kate above KdB, using its long range to stay up for the entire engagement, directing elements from its vantage point at, say, 15-20,000 ASL.

 

[Admiral Beez]

A major strategic failing of the IJN was its insistence that all its aircraft have supremely long range.

What Japan needed was a consolidated fighter for both services. An F4 Phantom II, serving everyone, for example. Impossible because the army and navy couldn't get along.

 

[Thumpalumpacus]

What Japan needed was a consolidated fighter for both services. An F4 Phantom II, serving everyone, for example. Impossible because the army and navy couldn't get along.

That certainly would have simplified supply chains. But I think Consolidated was an American company.

 

[Reluctant Poster]

IIRC, at Midway fighter direction consisted of screening cruisers firing in the direction of an incoming wave, at points even using main-battery guns. About as inefficient as one could imagine.

Hell, if nothing else, orbit one fighter or Kate above KdB, using its long range to stay up for the entire engagement, directing elements from its vantage point at, say, 15-20,000 ASL.

That was the Japanese system. Radar would have helped immensely but without a "Filter Room' to coalesce the data even radar doesn't do much.

 

[Thumpalumpacus]

That was the Japanese system. Radar would have helped immensely but without a "Filter Room' to coalesce the data even radar doesn't do much.

True enough, the Americans discovered this in the autumn of 1942. Eastern Solomons and especially Santa Cruz were the prime drivers for the implementation of the CIC on ships sized destroyer and larger, to my understanding. American fighter patrols were found to be weak in numbers and often out of position because the radar information wasn't collated and delivered in a timely manner.

Information is great, dissemination is priceless.

 

[Shortround6]

Tojo's stall speed (with its non-laminar wing) was around 93 MPH

We really do have to be careful we are comparing the same things. Especially with translations from other languages.

Stall speeds are often quoted at different weights (full load, mean weight or light)
but the next step up is often called different things like landing speed or alighting speed .
Which is different from approach speed.

Looking at the reports for the Hurricane I prototype we can find

Stalling speed (weigh not given unless full weight) but with flaps open
Stalling speed with flaps shut (notice not up or down
Landing speed.
Gliding speed.

Hurricane K-5083 Trials Report

WWII Aircraft Performance, wartime flight trials and reports of Hurricane aircraft. Hurricane data.

www.wwiiaircraftperformance.org

You can find other ones.

Stall speed is exactly that, the plane stalls (stops flying and drops quickly) and is dependent on weight/wing loading and flaps.

there is sometimes a suggested landing or alighting speed ( just enough extra above stall to allow for control with a margin of error but not so high that the landing run is excessive.

Landing speed is variable as it may be a somewhat declining speed. You want to cross the fence or threshold with more speed than you touch at so that you don't run out of airspeed too soon.

Sometimes you have to guess as to what is meant.

And sometimes landing stall speed is not the same as take-off stall (different flap settings) and if you drop the flaps too much for take-off the increased drag increases you take-off roll.

 

[Admiral Beez]

That certainly would have simplified supply chains. But I think Consolidated was an American company.

True, true. If the Nakajima Ki-44 can be made carrier-capable without dramatically impacting its performance then the whole IJNAS/IJAF can settle on this one bird. Then both services will move onto the superlative Nakajima Ki-84. We might need cats on the carriers though.

 

[Shortround6]

No tricks can be seen on that picture, just a job well done

the extended wing screen might have been worth 5-6mph?

The small openings in the cowlings may have helped speed. No idea if they overheated in climb.
For a recon plane that cruised fast they may have worked very well.

For a fighter that needed to climb or accelerate after a hard turn maybe not so good. High power and low airspeed sometimes didn't work well

I would also note that the F6F's canopy height and slope down to the nose not only helped with landings, it allowed higher angle defelection shots before the target got hidden by the cowl, not a problem with recon aircraft

 

[Shortround6]

True, true. If the Nakajima Ki-44 can be made carrier-capable without dramatically impacting its performance then the whole IJNAS/IJAF can settle on this one bird. Then both services will move onto the superlative Nakajima Ki-84.

That would require repealing the laws of physics.
The KI-44 had a 161 sq ft wing and a wing loading of around 37.7 lb/sq/ft.
The Zeros started at 22 lb/sq/ft. ended closer to 26-27lb sq/ft.

BTW that is for the Ki-44 without underwing fuel. You want to take-off and land like a Zero you need around 70-80 more sq ft of wing.
The bigger wing will weigh around 200-250lbs (or more?)
A roughly 50% bigger wing will do what to the speed performance?

The Ki-84 isn't as bad but unless you can fix the engines (and landing gear, and brakes) you don't have a chance of turning it into carrier fighter.

 

[GrauGeist]

IIRC, at Midway fighter direction consisted of screening cruisers firing in the direction of an incoming wave, at points even using main-battery guns. About as inefficient as one could imagine.

Hell, if nothing else, orbit one fighter or Kate above KdB, using its long range to stay up for the entire engagement, directing elements from its vantage point at, say, 15-20,000 ASL.

There were several eff-ups regarding the IJN's CAP.
First was too few aircraft, coupled with lack of organization.
When the VTs attacked, all the defenders dove down to intercept, leaving none in place to defend against subsequent attacks. This also caused many of the A6Ms to run low on fuel and ammunition, too.
There wasn't a cohesive schedule between the carriers to provide a balanced rotation and zones for the CAP, either. The rivalry between individual carrier groups was almost on a level of the rivalry between the IJN and IJA.

Add to this, the fleet's scouts were not coordinated, either.

In regards to the surface screen, they were too far out to be of any help with their AA.

 

[Thumpalumpacus]

There were several eff-ups regarding the IJN's CAP.
First was too few aircraft, coupled with lack of organization.
When the VTs attacked, all the defenders dove down to intercept, leaving none in place to defend against subsequent attacks. This also caused many of the A6Ms to run low on fuel and ammunition, too.

Yep, that's why I'd think having a master controller airborne would have been a better solution than the "every man for himself" approach that saw CAP concentrating on one formation to the exclusion of others. To be fair, there's quite a bit of hindsight in my writing this; the Japanese had no idea they'd so thoroughly maul the VTs, and probably thought they needed max force against torpedo planes due to threat.

There wasn't a cohesive schedule between the carriers to provide a balanced rotation and zones for the CAP, either. The rivalry between individual carrier groups was almost on a level of the rivalry between the IJN and IJA.

I sometimes wonder if it wouldn't have been wiser to keep one or two of their CVs as designated CAP-carriers (with reserve striking forces stowed in the hangar) rather than parceling out the detail in such an uncoordinated matter. There's a fair bit of hindsight on my part there, too.

Add to this, the fleet's scouts were not coordinated, either.

In regards to the surface screen, they were too far out to be of any help with their AA.

Well, even if the screen had been tucked in tight, the 25mm cannons they carried in relatively small, early-war numbers probably wouldn't have been much use anyway. It'd also mean that an American torpedo which missed a carrier would perhaps have a chance at striking a cruiser standing by on AA duty.

 

[SaparotRob]

In regards to the surface screen, they were too far out to be of any help with their AA.

I think one the main strategies for air defense of the IJN CVs was maneuvering. Close in escorts would get in the way.

 

[Greg Boeser]

Well, if you are satisfied with a 350-360mph aircraft in 1942/43 you might have gotten it (barely). If you are trying for the 370mph airplane the things are harder.

Or will the A6M with the 1942 Kinsei engine be fast enough? Or do you have to wait for 1943?

Just opened my new book on Japanese aero engines and it is missing 4 pages right at the end of the Mitsubishi chapter on the pacific war period (all the Mitsubishi engines we are interested in) all but one of the data tables for the Mitsubishi engines.

The Japanese were short on power and tried to substitute aerodynamic tricks
View attachment 690716
Some planes could get away with it, some gave more troubles with poor vision or cooling or whatever.

Stop!! this is airplane porn!
Oooh, Baby! Don't stop!

 

[Reluctant Poster]

The problem with the Zero at Midway wasn't its performance. It had for its era an exceptional rate of climb which is the key parameter. It failed due to a complete lack of a fighter direction system. The USN proved during 1942 that, while their fighter direction system didn't perform up to expectations, an underperforming fighter direction system was much, much better than none at all.

One of the major shortcomings of the F4F, particularly in the F4F-4 version, was its anemic rate of climb. I reviewed the test data for the F4F-4 vs the Zero on the WWII Aircraft Performance website and the difference was astounding. Basically, the Zero could climb to 20,000 feet in little more time than the F4F-4 took to get to 10,000 feet. This is a massive advantage in the interceptor role.

I tried to select the best test I could find for each. F4F-4 is at military power.

The Zero was far and away the best performing shipboard interceptor of 1942 but was sabotaged by the Japanese having no fighter control. I think a case can be made that the Japanese made the correct decision in not providing their fighter pilots with self-sealing fuel tanks and armor (I would not say the same for bombers). As I have pointed out in the past the death rate for Zero pilots wasn't significantly higher than for F4F pilots and the death rate for all fighter pilots in general was much, much lower than that for bomber crew. When defending an extremely high value target like an aircraft carrier a 2 or 3 more dead fighter pilots is more than acceptable if it prevents a bomb from hitting the ship.
The greater endurance of the Zero was theoretically also a great advantage as it allowed greater flexibility in CAP operations. Again, this advantage was largely negated by the Japanese lack of fighter direction.

 

[Shortround6]

Unfortunately the often listed sources are often at at odds with each other.

The Zero was a much better at climb that the F4F-4 but something seems off on the F4F figures.

I would note that the F4F has some problems with military power and normal power.

Apparently the R-1830 engine in the F4F-4 had problems with inadequate intercooling or inadequate cooling or both. Military power in hi blower was at the same rpm as normal power while in either neutral or low blower it was allowed to run 150rpm higher. 2700rpm instead of 2550rpm.
The engine was noted as running rough in hi blower at high rpm and there was very little gain in speed (2.5 kts?) and that the carb intake temperature was high (which will increase the cooling load on the engine.)

A number of charts show the F4F-4 climbing in the low 1000fpm range at 20,000ft, not 900fpm. Now 1200-1300fpm isn't on a par with the Zero but it was not as bad as 900.
So far the a only chart that shows 900fpm at 20,000 ft is while carrying a pair of drop tanks.

 

[XBe02Drvr]

The Zero was far and away the best performing shipboard interceptor of 1942 but was sabotaged by the Japanese having no fighter control.

The greater endurance of the Zero was theoretically also a great advantage as it allowed greater flexibility in CAP operations. Again, this advantage was largely negated by the Japanese lack of fighter direction.

I remember reading (long ago, I've forgotten where) that if the Japanese had a better understanding of the significance of bonding jumpers, ignition interference suppression, and static discharge systems in all radio equipped aircraft, not just long range scouts, Midway and the course of the war in general might have been very different. Apparently, radios from captured Japanese combat aircraft worked just fine on the test bench, but very poorly in flight.

 

[Conslaw]

True, true. If the Nakajima Ki-44 can be made carrier-capable without dramatically impacting its performance then the whole IJNAS/IJAF can settle on this one bird. Then both services will move onto the superlative Nakajima Ki-84. We might need cats on the carriers though.

On the other hand, if the IJN and IJA had agreed on a joint service fighter, but if the Army's pull would have resulted in that being the Ki-43 instead of the A6M, The IJN would have ended up with a massively inferior fighter. The Ki-43 in land-based form was both slower and more lightly armed than the A6M. In theory, the Ki-43 would have required extra weight for carrier duty, so the naval version would have performed even worse, maybe losing the Ki-43's outstanding climb rate.

 

[FLYBOYJ]

On the other hand, if the IJN and IJA had agreed on a joint service fighter, but if the Army's pull would have resulted in that being the Ki-43 instead of the A6M, The IJN would have ended up with a massively inferior fighter. The Ki-43 in land-based form was both slower and more lightly armed than the A6M. In theory, the Ki-43 would have required extra weight for carrier duty, so the naval version would have performed even worse, maybe losing the Ki-43's outstanding climb rate.

And "if" it was the other ay around and the JAAF accepted the Zero?

The Ki-43, although slower and lightly armed was no slouch and was reported to be even more maneuverable than the Zero.