Jack vs. Tojo - Which was better? Why?

[alejandro_]

Many years ago I made a comparison of Ki-44 with different fighter aircraft of 1942-43 and 44-45. Even late in the war the climb rate was competitive.

1942-43:

1944-45:

I am planning to update the article at some point. Perhaps someone has suggestions on other aircraft to which it could be compared, especially in 1942-43 (Buffalo, Hurricane...).

 

[Kevin J]

A better comparison for the Raiden would be the Ki-61-II / Ki-100. They're deliverable in the same timescale.

 

[CORSNING]

Ivan,

The speed advantage is also mostly at very high altitude where the J2M probably would not be.

The P-47N escorted the B-29s. Original bombing of the B-29s over Japan was its
cruising altitude of 30,000 ft. Later it was restricted to night missions at a lower
level. I am not a historian of bomber aircraft, so I do not know at what altitude
the night missions were flown at.

The J2M as mentioned has a particularly high power to weight ratio and probably a very good acceleration as a result and that may lessen the apparent speed difference.
Agreed sir. The Raiden was a more dynamic aircraft.


Jeff

 

[Greg Boeser]

Night bombing was conducted under 10,000'.

 

[XBe02Drvr]

I'm not saying the Raiden will outperform the P-47N even if its only at 52", but data sheet racing isn't combat proof

So what does history have to say about combat proof? How often did they actually meet in combat? What were the outcomes? What did the pilots have to say?
The scenario depicted above by Mike Rauls makes a lot of sense. Given the P47's altitude performance and the B29s' daylight bombing altitudes (pre LeMay), they were likely flying top cover, if they were there at all, and thus likely to be bouncing Raidens from above. (Port Moresby redux, with the roles reversed.) I had always understood those long range B29 escort missions to be a Mustang show.
Cheers,
Wes

 

[Zipper730]

Night bombing was conducted under 10,000'.

Just to be clear, did they climb to 14000-25000 feet then drop to below 10000 feet prior to bombing or just cruise in and out at below 10000 feet above MSL.

 

[Shortround6]

It might depend on the mission, but climbing to 25,000 on the way in could burn hundreds (many hundreds) of gallons of fuel. By not climbing to 25,000ft they could carry more bombs further.

 

[Zipper730]

It might depend on the mission, but climbing to 25,000 on the way in could burn hundreds (many hundreds) of gallons of fuel. By not climbing to 25,000ft they could carry more bombs further.

From what I remembered...

1. Cruising high allows more speed for the same engine power
2. Climbing to higher altitude expends more energy than climbing to a more moderate altitude (big problem if climb-rate is far too slow)

I would have thought that climbing to 10000' would reduce energy to climb, but would have required more energy to carry it along, I figured 15-25k would be high enough to reduce drag and increase speed, yet not too much to undermine fuel consumption.

 

[Ivan1GFP]

Ivan,

The speed advantage is also mostly at very high altitude where the J2M probably would not be.

The P-47N escorted the B-29s. Original bombing of the B-29s over Japan was its
cruising altitude of 30,000 ft. Later it was restricted to night missions at a lower
level. I am not a historian of bomber aircraft, so I do not know at what altitude
the night missions were flown at.

The J2M as mentioned has a particularly high power to weight ratio and probably a very good acceleration as a result and that may lessen the apparent speed difference.
Agreed sir. The Raiden was a more dynamic aircraft.


Jeff

Hello Corsning,
Years ago, I asked a related question to a fairly knowledgeable fellow about why the B-29s didn't continue to bomb from around 30,000 feet where they were pretty much immune to interceptions.
His explanation was that although the B-29 could easily sustain those altitudes, bombing accuracy was pretty lousy because of the wind conditions (Jetstream) at that altitude. It made more sense to bring the bombers down lower so they could actually hit something. By that stage of the war, interceptions by fighters were not considered to be as risky to the point that most of the bombers were not carrying all their defensive armament anymore anyway, though tail guns were usually retained.

Another interesting tidbit to consider is that the J2M3 as tested by TAIC was actually a bit faster than your chart shows. It should be 417 MPH. 407 MPH is the speed attributed to the J2M2 that was tested.
The J2M3 sometimes had broad blade propellers installed, but the one that was tested did not have those.
They can be recognized by corners at the root of each propeller blade. I don't know if that difference would have improved speed, but I would expect that a bigger propeller would not have been installed if it didn't help anything.

- Ivan.

 

[XBe02Drvr]

It might depend on the mission, but climbing to 25,000 on the way in could burn hundreds (many hundreds) of gallons of fuel. By not climbing to 25,000ft they could carry more bombs further.

I would have thought that climbing to 10000' would reduce energy to climb, but would have required more energy to carry it along.

Turbocharged recips don't suffer the huge low altitude fuel penalties that gas turbine aircraft do. A jet or turboprop B29 would have needed to climb to FL300 or higher for the long haul, even if attack altitude was 10K or less. Flying all the way at attack altitude would burn less fuel overall and keep them under the radar horizon much closer in to the target. That last 10K of climb in the thin air above 20K would be a long, slow, thirsty slog for heavily laden B29s.
On my way back from Aircraft Escape and Rescue Training at NAS Cecil, I hitched a jump seat ride in an Eastern DC9-10 from JAX to MIA with a couple of Navy trained Eastern pilots, both still active in the reserves, and both former "mustangs". Our flight profile (not the standard filed flight plan) was a max rate climb to FL260, 50 miles NE of Orlando, then a flight idle descent into MIA. It was late at night, we were high on the approach profile, traffic was dead, and the crew talked the controller (another ex-squid) into letting us do a high altitude military style teardrop penetration approach (not a peep from the cabin, just snores). The power levers stayed at idle until it was time to dirty up for landing. Fuel burn beat the programmed number for the standard FL180 flight plan by 15%, and we beat the scheduled flight time by 7 minutes. That's how dramatic the altitude difference is with turbines.
One of my buddies from the flying club taxied up to the gate as we were deplaning about 0100 (on to the tarmac; jetways all occupied by morning departures), and got me back to NQX in time to catch a few winks before morning muster.
Biff, Flieger, and any other active airline pilots out there, that was nearly fifty years ago, and rules were a tad different then. I even got my Commercial and CFI without an Instrument Rating at first. Had to upgrade in 1975.
Cheers,
Wes

 

[taly01]

However if you are trying to decide which was the better plane in late 1942, all of 1943 and most of 1944 then the Tojo wins

More widespead use of the Ki-44 in 1943 is one of the great "what-ifs" for Japanese aircraft. It never happened for several reasons
1) Range for Ki-44 was much less than Ki-43/61, and in the South Pacific range is king,
2) Handling of Ki-44 was much more difficult than Ki-43/61 both in flight and especially landing for new pilots.
3) Ki-61 was the standard new fighter for 1943 that met all requirements. (unfortunately was unreliable maintenance nightmare).

They did send extra Ki-44 to Burma in mid'44 to counter the newly arrived Spitfire VIII. From memory they didn't perform much better than the Ki-43 already there.

 

[CORSNING]

Hello Corsning,
Years ago, I asked a related question to a fairly knowledgeable fellow about why the B-29s didn't continue to bomb from around 30,000 feet where they were pretty much immune to interceptions.
His explanation was that although the B-29 could easily sustain those altitudes, bombing accuracy was pretty lousy because of the wind conditions (Jetstream) at that altitude. It made more sense to bring the bombers down lower so they could actually hit something. By that stage of the war, interceptions by fighters were not considered to be as risky to the point that most of the bombers were not carrying all their defensive armament anymore anyway, though tail guns were usually retained.

Thank you for the added information sir.

Another interesting tidbit to consider is that the J2M3 as tested by TAIC was actually a bit faster than your chart shows. It should be 417 MPH. 407 MPH is the speed attributed to the J2M2 that was tested.

Hi Ivan, if you are referring to the chart on post #33 the numbers posted are for a J2M2 Jack 11..

The J2M3 sometimes had broad blade propellers installed, but the one that was tested did not have those.
They can be recognized by corners at the root of each propeller blade. I don't know if that difference would have improved speed, but I would expect that a bigger propeller would not have been installed if it didn't help anything.

More great information sir. I will have to look into this.

- Ivan.

 

[BiffF15]

Turbocharged recips don't suffer the huge low altitude fuel penalties that gas turbine aircraft do. A jet or turboprop B29 would have needed to climb to FL300 or higher for the long haul, even if attack altitude was 10K or less. Flying all the way at attack altitude would burn less fuel overall and keep them under the radar horizon much closer in to the target. That last 10K of climb in the thin air above 20K would be a long, slow, thirsty slog for heavily laden B29s.
On my way back from Aircraft Escape and Rescue Training at NAS Cecil, I hitched a jump seat ride in an Eastern DC9-10 from JAX to MIA with a couple of Navy trained Eastern pilots, both still active in the reserves, and both former "mustangs". Our flight profile (not the standard filed flight plan) was a max rate climb to FL260, 50 miles NE of Orlando, then a flight idle descent into MIA. It was late at night, we were high on the approach profile, traffic was dead, and the crew talked the controller (another ex-squid) into letting us do a high altitude military style teardrop penetration approach (not a peep from the cabin, just snores). The power levers stayed at idle until it was time to dirty up for landing. Fuel burn beat the programmed number for the standard FL180 flight plan by 15%, and we beat the scheduled flight time by 7 minutes. That's how dramatic the altitude difference is with turbines.
One of my buddies from the flying club taxied up to the gate as we were deplaning about 0100 (on to the tarmac; jetways all occupied by morning departures), and got me back to NQX in time to catch a few winks before morning muster.
Biff, Flieger, and any other active airline pilots out there, that was nearly fifty years ago, and rules were a tad different then. I even got my Commercial and CFI without an Instrument Rating at first. Had to upgrade in 1975.
Cheers,
Wes

Wes,

My first half of Undergraduate Pilot Training was in the mighty Tweet, AKA the T-37. It was a huge part of instrument flying to regularly do the dreaded teardrop penetrations that your DC-9 friends so readily demo'd. I didn't mind doing them but they are much more demanding than radar vectors to the ILS / visual.

From what I understand the penetration approach was designed for the early jets which had tremendously short legs or very high fuel burns. It allowed for an almost entirely flown in idle descent approach and the navaid was usually on the destination airfield. The Tweet was a fairly early jet.

We even did them in the T-38 which could be a handful as it required a bit quicker thinking and much greater lead turns (for level off or turns from an arc to a radial or vice versa). Penetrations were flown at 300kias (Eagle at 350kias until entering the pattern / downwind) with a Tacan, DME and an ILS. Flight director only for the ILS for both a/c.

KROW HI-ILS OR LOC RWY 21 (IAP) ✈ FlightAware

This one was called the Widow Maker. You would sign the wall under the "I beat it" or "It beat me" areas in the FBO. Yes, that Roswell from little green men fame.

Cheers,
Biff

 

[CORSNING]

2) Handling of Ki-44 was much more difficult than Ki-43/61 both in flight and especially landing for new pilots.

From Aircraft of the Aces 100 by Osprey page 16:
"The Ki-44 was at first restricted to pilots with at least 1000 hours of flying
time because of its tricky handling characteristics, but it was later found
that younger pilots who had not been instilled with the extensive aerobatic
training of earlier cadres could manage the aircraft perfectly well, so the
restriction was removed."
We must remember that the "fast landing speed and trick handling" that so
many publishers use is comparing the Ki.44 to such aircraft as the Ki.27, Ki.43
A5M and A6M. Those terms would apply to every late war US fighter except
the P-40N and FM-2 by comparison.

 

[CORSNING]

1) Range for Ki-44 was much less than Ki-43/61, and in the South Pacific range is king,
Agreed.

Ki.44-II: 740 ml/174 mph/128 g internal fuel, 1,050 ml/166 mph/197 g w/drop tanks.
Ki.61-I: 1,195 ml/215 mph/215 g internal, 2,010 ml/148 mph/299 g w/drop tanks.
Ki.43-II: 1,180 ml/145 mph/149 g internal, 1,745 ml/137 mph/137 g w/drop tanks.
J2M2m11: 650 ml/165 mph/109 g internal, 1,127 ml/156 mph/223 g w/drop tanks.
All ranges are at 1,500 ft.

 

[XBe02Drvr]

From what I understand the penetration approach was designed for the early jets which had tremendously short legs or very high fuel burns. It allowed for an almost entirely flown in idle descent approach and the navaid was usually on the destination airfield.

On weekends when they weren't doing syllabus hops, the F4 and A4 guys would go out and do penetrations over the field from 20K. Unrestricted climb followed by a "dead stick" (flight idle and just enough "boards out" to compensate for the residual thrust) teardrop approach to a touch and go and do it all again. An F4 could manage just about 4 reps on internal fuel; an A4 could just about squeak out 5. We never had to wait for Navy Day or the 4th of July for an airshow; between the Grim Reapers and the Beaufort Harriers, we had an airshow most weekends. But for those hapless mid shift workers who had to sleep in the daytime, it was an unholy PITA.
Cheers,
Wes
PS: OMG, that Roswell approach is one busy SOB! If you're in a Talon, you're category E, right? Way busier than the basic teardrop. The roll in to the localizer's got to be bear at Talon speeds. Peg the needle and go missed. There's no saving it at that point. With circling minimums that high, there must be high terrain nearby.

 

[XBe02Drvr]

The Tweet was a fairly early jet.

Wasn't it the last jet to enter service with centrifugal compressor engines? That J69 is a cute little kerosene powered siren. We had a Tweet drop in at our field with a powerplant casualty when I was working in the shop at the commuter. It sat over at the Air Guard for several days waiting for the AF to fly in a new engine and a engine change crew. The Air Guard offered to do the work, but the pilot, a fresh out of UPT FAIP with a shiny butterbar, said he was not allowed to let weekend warriors touch his bird. So stated, as he gazed longingly at the F16s being upgraded to a later block configuration. Some of my fellow mechs were in the Guard, so when we went on our midrats break, we would stop over and check progress on the Tweet. For what should have been a simple operation, it sure took long enough. The crew they flew in were a bunch of young kids led by an E6 who looked like he belonged in high school.
The Tweet pilot hung around for days with nothing to do and bemoaning his fate. Seems he had his heart set on being a fighter pilot, but instead they made him an instrument instructor and sent him around to do proficiency rides with senior officers who were aviators but assigned to non-flying billets. Not a particularly ego-gratifying activity.
Cheers,
Wes

 

[BiffF15]

Wasn't it the last jet to enter service with centrifugal compressor engines? That J69 is a cute little kerosene powered siren. We had a Tweet drop in at our field with a powerplant casualty when I was working in the shop at the commuter. It sat over at the Air Guard for several days waiting for the AF to fly in a new engine and a engine change crew. The Air Guard offered to do the work, but the pilot, a fresh out of UPT FAIP with a shiny butterbar, said he was not allowed to let weekend warriors touch his bird. So stated, as he gazed longingly at the F16s being upgraded to a later block configuration. Some of my fellow mechs were in the Guard, so when we went on our midrats break, we would stop over and check progress on the Tweet. For what should have been a simple operation, it sure took long enough. The crew they flew in were a bunch of young kids led by an E6 who looked like he belonged in high school.
The Tweet pilot hung around for days with nothing to do and bemoaning his fate. Seems he had his heart set on being a fighter pilot, but instead they made him an instrument instructor and sent him around to do proficiency rides with senior officers who were aviators but assigned to non-flying billets. Not a particularly ego-gratifying activity.
Cheers,
Wes

Wes,

What year was that? I went through in 1988-89 and we had contract MX at Vance AFB. I went through AT-38s at Holloman AFB immediately following and they were contract as well (mostly ex USAF).

It's not unusual for one unit to not let another do work on their jets. In the Eagle when going cross country you usually made every other stop at another F15 base so the jet could get some love from someone familiar with the type. I would often hit Sheppard AFB as well which is where they make Eagle Crew Chiefs.

Cheers,
Biff

 

[XBe02Drvr]

What year was that?

In the winter of 1984/85, I forget the exact date. The Air Guard had just traded in their F4Ds for some 1st generation F16s which needed to be upgraded before they could go on line. They did that so swiftly and efficiently that USAF started sending other units' birds to them for upgrading. They had an experienced and mature maintenance force with a lot of retired career NCOs working there full time (not your average weekend warrior outfit), and became a designated F16 upgrade center, as they had been for the F4, EB57, and F89 previously.

It's not unusual for one unit to not let another do work on their jets.

If that Tweet had contract maintenance at home, I suppose the contractor would be a little leery as to who was going to fiddle with his jets. OTOH, that bunch of kids they sent to do the engine swap looked pretty military to us. A band of 2 and 3 stripers on a shop floor where almost everyone was wearing 5 or more. The old timers labeled them (privately) as "the Keystone Kops" and intervened only once, to prevent what could have been a serious injury.
The Guard even had access to up to date tech pubs on all USAF active aircraft types, and were able to supply an update on the Tweet that the kids were unaware of.
I think it's time to get back to Tojo and Jack (sound like a 1980s cop show?), don't you?
Cheers,
Wes

 

[taly01]

From reading Jiro Horikoshi (who designed A6M and J2M) Zero data book he had a note ...although A6M5 was planned as last Zero, production had to increase due to Raiden problems.....seemed strange and wrong to me. But reading more information from the Japanese sources the Raidan WAS planned to substantially replace the Zero. However over 1943/44 the early production Raiden had some hard to solve resonance failures, and at this time the N1K1-J was almost ready for production, and in comparative trials the N1K1-J easily outmaneouvered the J2M3 and had much longer range.

So the J2M3 production almost stopped in early 1944 and N1K1-J was put into priority production, however by the time all this had happenned the Homare engine in the N1K1-J was quite unreliable in service and also had undercarriage faults and other design flaws. Meanwhile the vibration resonance had mostly been solved in the J2M by new engine mounts and new thicker propeller blades.

Then they found the Raiden was one of the best B-29 intererceptors and tried to bring as many as possible into new specification but only ~600 ever made. Definately unique design!