Rising Sun warbirds

[FLYBOYJ]

one other interesting fact about the design of the Zero........ the IJN wanted the design of the airframe to allow for the engine to be changed quickly. I think it took less than 30 minutes for a complete engine change as compared to hours with the F4F.

Indeed, former Vought Engineers claim that the Zero's QEC package drew heavily from the Vought V-143 fighter prototype, sold to Japan in 1938. One Engineer stated that the entire accessory section layout was pure Vought.

Japan did not copy western aircraft per se, but they were wise enough to borrow useful technology, as did everyone else. Even Kurt Tank admitted to having been greatly influenced by Palmer's design (aka, the Hughes H-1). No one designs in a vacuum, not Mitchell, not Kartvelli, not Willie or even Camm. Everyone draws from the work of everyone else.

My regards,

NAVAIR

Agree - I read somewhere the F8F had some inspiration from the FW-190 (landing gear)

 

[R Leonard]

the IJN wanted the design of the airframe to allow for the engine to be changed quickly. I think it took less than 30 minutes for a complete engine change as compared to hours with the F4F.

I don't know from where "hours" to change out an F4F engine comes from. I spoke this evening with a wartime F4F maintenance type who reported that, presuming one had all one's tools at hand, a couple of engine hoists, and a three or four of extra pairs of hands coupled with brains that knew what they were doing, you could change out, one for another, an F4F engine in under an hour, if you took your time; faster if you were in a hurry.

Frankly, incorporating ease of maintenance is not rocket science. I know of one USN F4F driver (same gent who was flying A6M2 #4593 in the fall of 1944) who had a barrier landing on the night of 7 May 1942 aboard USS Yorktown. His plane was struck below. He debriefed and then went to chow. He then went to the hangar deck to see how his plane was coming along and found the VF-42 maintenance guys were just starting to put on the cowl ring, having already replaced the engine. He hung around until the engine had been tested and then turned in. He flew that plane the next day.

Regards,

Rich

 

[FLYBOYJ]

Great info Rich!!!! Even if an F4F engine change took "hours" say with two guys, you got the ole CPO's mentality - "Here's six guys, get it done in an hour."

 

[carpenoctem1689]

It didnt matter if the F4F took four, or five hours really, becaue theyre were more planes, engines, and better trained maintenance crews to do the job. the zeros werent produced in good enough numbers, and the same can be said about the pilots, maintenance crews, and powerplants. I repsect the IJNAF and the IJAAF because they accomplished alot with what they had, but the americans, could outpace them in technology, trainign, and numbers.

 

[syscom3]

The IJN did have concerns about the quality of the recruits for maint. of the aircraft, thus did incorporate such things into the design, where they could.

"Frankly, incorporating ease of maintenance is not rocket science. ".... well that might be true, but it isnt always implimented. Plenty of products then and now that the design groups decided it wasnt necessary.

 

[FLYBOYJ]

Speaking as a maintainer - with the tools and equipment readily available, it should take under an hour to change an engine on either airplane....

 

[carpenoctem1689]

Yes, with the tools and equipment readily available, something the japanese lacked later on in the war. while the conditions and availability for the allies was growing...if you look at the service like of the sakae engine that powered the zeroes, or the engine of an F4F, later in the war, maintenance time, changing speed, and service life were probably all longer, due to quality of products and technicians.

 

[evangilder]

Having turned a wrench on the Zero a couple of times, I can tell you that there were parts that were obviously not mass machine produced. The prop spinner only fits on in one position. If you are off one screw hole, you have to keep turning until you find the right alighment. The obvious thing to do is mark the alignment before disassembly! Lesson learned. The cowling on the Zero is not a fun item to put back on. The turn buckle screws don't leave much room for turning a wrench on them.

That being said, aside from issues with hand sizes (Americans today have bigger hands than the Japanese of the 1940s, generally), it's not too bad. But our Zero has quite a few Dzus fasteners, not standard for the time on Japanese aircraft.

 

[Parmigiano]

Rich,
thank you for your search and info.
Yes, the report in my book (the great book of WW II airplanes, Crescent books, AAVV - a wonderful book specially for the many detailed drawings from R.Watanabe) is the same you linked.

I re-read the report, and I still have the impression that the zero was holding very well or outperforming the other aircrafts.
- the lower performance above 500 kmh (300mph) fall in a limited envelope of use, most of the dogfight was below that speed. It only tells that zero should not try to escape by diving and could be escaped in a steep dive, assuming there is enough space below.
- the zero SN 4593 was recovered after a forced landing due to engine trouble. The machine landed wheels down on a marsh, breaking landing gear, flipping over and breaking tail, propeller and canopy in the process: not a small damage, that had to be rebuilt without any supporting documentation. It seems fair to assume that a factory-fresh zero would have probably performed a bit better.
Consider that probably (unless the US manufacturer behaved against their natural attitude to competition ) the US fighters sent for comparison were in mint conditions.
- the engine cut-off is reported only for this zero, at least I never heard/read of this as a general problem of the machine. Also because the US pilots (.. that were NOT slow in learning) would had used this as a standard escape tactic, like the 109 pilots did with the early spits.
- Although the pilots who flew the zero were surely great pilots they did not know very well the ship, and were probably not in condition to 'squeeze' the best out of it, while the pilots in the local planes of course knew them 'like their pockets' : put a Saburo Sakai in the cockpit and the zero would had performed better in climbs and turns!

All this, specially if you read the comparison with the F4F where no numbers are given but just a kind of concerned statements (..zero was superior in speed and climb at all altitudes above 1000 ft .. superior in ceiling... no comparison between the turning circles... in combat F4F is basically dependent in mutual support..) states that at the end of 1942 the zero model 21 was at least a terrible customer for the US planes, and that the new generation of US fighters (Corsair) was better than the Zero.

What was not highlighted is the fragility of the zero in sustaing battle damage.

The problem of the japanese fighter is that it was not substantially improved in the following 3 years, with an evolution path similar to her western counterparts (because of HQ policy? because the structure could not hold more power and weight? because no better engines were available?), making it completely obsolete by 1943.
.. put a 1700hp BMW 801, some armour and metal ailerons in that frame and, if it holds together , you probably have an airplane that can match the opponents in 43-44

 

[evangilder]

Metal ailerons wouldn't make a difference. Even as they were, beyond about 275 MPH, the ailerons are like concrete, according to the pilot that flies our zero. Armor would help, but it adds weight, as well as a bigger engine would. These could also effect the performance of the airplane.

 

[syscom3]

The Zero seems to have been a dead end evolutionary wise. Excellent plane to start out the war, but was eventually neutralized by better allied designs.

At Chino 2000, I was talking with a 475th FG pilot and he mentioned that no matter how much training the Allied pilots had, there was always someone who didnt believe how deadly the Zero could be, and once in awhile they would pay the price.

Several years ago I worked frequently in Japan and had some interesting conversations with my Japanese colleagues, and one of them summed up the state of Japanese aircraft industry in 1942....."we could build lots of existing planes.....or.....design new planes, but we didnt have the resources to do both".

 

[Parmigiano]

Armor would help, but it adds weight, as well as a bigger engine would. These could also effect the performance of the airplane.

Exactly Evan, it would have moved the zero attitude from the 'turn-and-burn' to 'boom-and-zoom' side, like the evolution that Spitfire and 109 had.
Less endurance and manouvrability traded for higher speed, payload and durability, that was the right recipe from 42 to 45!

I just mentioned the aileron per analogy, because I remember it cured the same issue on the spitfire, whose fabric surfaces were 'balooning' at high speed making the stick unmovable. I think it was fixed during MkV production with aluminium covered ailerons.
I read that the zero was improved in high speed handling by cutting the wingtips and fitting smaller ailerons, but I believe the old saying 'there is no plane better than her engine' and 1100hp were about half the power of the competition.

 

[Parmigiano]

Armor would help, but it adds weight, as well as a bigger engine would. These could also effect the performance of the airplane.

Exactly Evan, it would have moved the zero attitude from the 'turn-and-burn' to 'boom-and-zoom' side, like the evolution that Spitfire and 109 had.
Less endurance and manouvrability traded for higher speed, payload and durability, that was the right recipe from 42 to 45!

I just mentioned the aileron per analogy, because I remember it cured the same issue on the spitfire, whose fabric surfaces were 'balooning' at high speed making the stick unmovable. I think it was fixed during MkV production with aluminium covered ailerons.
I read that the zero was improved in high speed handling by cutting the wingtips and fitting smaller ailerons, but I believe the old saying 'there is no plane better than her engine' and 1100hp were about half the power of the competition.

 

[evangilder]

Ballooning is not the problem with the ailerons in the Zero, it is the size. I would agree that smaler ailerons would have helped as the stick forces were the problem with the large ailerons. Obviously it would require quite a bit of engineering as added weight needs to be balanced right or the CG changes and thus the manueverability gets effected. Even then though, weight itself will also decrease manueverability somewhat.

 

[FLYBOYJ]

Ballooning on control surfaces will normally not occur when the fabric is new and in good condition. Early in the war I would guess "Irish Linen" was used which could easily weaken if put under continual strain and weather....

 

[R Leonard]

It didnt matter if the F4F took four, or five hours really, becaue theyre were more planes, engines, and
better trained maintenance crews to do the job. the zeros werent produced in good enough numbers, . . .

Huh?

First we hear how it takes hours to change out an engine on an F4F, which wasn't true.

Now rises the specter of thousands of F4Fs outnumbering the A6M series production. Well, that, also, is untrue.

A6M series production:

A6M1: 2 prototypes
A6M2-11: 64 includes 21 that could be considered prototypes
A6M2-21: 1429
A6M2-K: 517 includes 7 prototypes
A6M3: 3 prototypes
A6M3-22: 1541
A6M3-32: 340
A6M5: 2151
A6M5a: 105
A6M5b: 2330
A6M5c: 93
A6M6c: 1577 includes 1 prototype
A6M7: 490
A6M8: 1 prototype
Total A6M series production: 10,643

Of course, if you want to include the A6M2-N production of 327 including 4 prototypes, that gives a production
result of 10,970.

Now, F4F production:

XF4F-2: 1
F4F-3: 285
F4F-3A: 95
XF4F-4: 1
F4F-4: 1169
XF4F-5: 1
XF4F-6: 1
F4F-7: 21
XF4F-8: 2
Total F4F production: 1576

And if you want to add in the FM series of 1060 FM-1 and 4777 FM-2 that makes a total of 7,413; still somewhat
short of the non-float type A6M's total of 10,643

And if we look at the primary contemporary antagonists, the F4F-3, F4F-3A, and the F4F-4 production versus
the A6M2-21, A6M3-22, and A6M3-32, and don't count prototypes, the production totals were 1549 for the
F4F types and 3310 for the A6M types. Thus, we find the F4F production was less than half the contemporary
A6M production. We should also keep in mind a couple of other factors, such as the F4F-3 and F4F-3A did
not serve on carriers after May 1942 and not as a land-based front line fighter after June 1942. And that,
while A6Ms were confined to the Pacific theaters, F4Fs also served in the Atlantic, and were, thus, not all
committed to Pacific operations.

I guess that's another theory out the window, F4Fs did not outnumber their A6M counterparts, in anyway
you want to count it.

. . . and the same can be said about the pilots, maintenance crews, and powerplants. I repsect
the IJNAF and the IJAAF because they accomplished alot with what they had, but the americans, could outpace
them in technology, trainign, and numbers.

So, are you saying that the Japanese did well in spite of their almost ubiquitously abysmal long term
strategic planning? I'd pose, rather. that their results were exactly the results of their planning. They went
into a war that they could not have possibly won in the first place, basing their entire strategic concept on
what they thought the US would do instead of thinking about what the US could do.

Regards,

Rich

 

[FLYBOYJ]

Great stuff Rich! Yep - the Japanese planned for a 6 month war - how many times did Yamamoto say that?!?!

 

[R Leonard]

I re-read the report, and I still have the impression that the zero was holding very well or outperforming
the other aircrafts.

I guess I don't read it the same way.

- the lower performance above 500 kmh (300mph) fall in a limited envelope of use, most of the dogfight
was below that speed. It only tells that zero should not try to escape by diving and could be escaped in a steep
dive, assuming there is enough space below.

I believe the point was to remind USAAF pilots to avoid engaging in low speed turning contests and keep their
speed above the A6M2s optimal performance envelope (or maybe I've just read too many of these reports
or talked to too many pilots).

- the zero SN 4593 was recovered after a forced landing due to engine trouble. The machine landed
wheels down on a marsh, breaking landing gear, flipping over and breaking tail, propeller and canopy
in the process: not a small damage, that had to be rebuilt without any supporting documentation. It seems
fair to assume that a factory-fresh zero would have probably performed a bit better. Consider that probably
(unless the US manufacturer behaved against their natural attitude to competition) the US fighters sent for
comparison were in mint conditions.

And how do the performance statistics the tests revealed compare to the Japanese reported performance.
The Japanese rated the A6M2 variously at between 316 and 330 mph. What did the US tests find? How
shocking . . . they only pushed it up to 326 mph! I wonder what a high-time, well and truly used, A6M2
would turn up as opposed to a nice, clean, and tweaked, factory fresh, edition or even this rebuilt version.
The reality is that the average aircraft in action on one side is going to run up against the average aircraft
in action on the other; so what is important is not what the squeaky clean aircraft can do, but what the aircraft
that just returned from it's 100th sortie can do. This is a fairly obvious observation. I see nothing in the
report to indicate that any of the US aircraft involved were factory fresh. Looks to me like old number 4593
was pretty well pushed to it's limit.

One has to ask oneself, if you're going to repair an enemy aircraft in order to test its capabilities, does it
not make sense to repair it to the highest operational extent possible? And if you're going to test it, are you
not going to push to see exactly what it will do? Would any other courses provide the performance information
in which you're interested?

Let's look at some of the damage to #4593

4593 engine (USN Photo from my collection)

4593 being shifted for shipment (USN Photo from my collection)

4593 ready for shipment. Note damage to vertical stabilizer (USN Photo from my collection)

4593 under repair by USN personnel at North Island NAS
(USN Photo from my collection)

4593 under repair by USN personnel at North Island NAS
(USN Photo from my collection)

And in its operational condition

4593 in 1944 (USN Photo from my collection)

4593 in 1944 (USN Photo from my collection)

4593 in 1944 (USN Photo from my collection)

4593 in 1944 (USN Photo from my collection)

4593 in 1944 (USN Photo from my collection)

- the engine cut-off is reported only for this zero, at least I never heard/read of this as a general problem
of the machine. Also because the US pilots (.. that were NOT slow in learning) would had used this as a
standard escape tactic, like the 109 pilots did with the early spits.

On the other hand I've read that the problem was corrected in later (the 22, 32, and 52) models.

- Although the pilots who flew the zero were surely great pilots they did not know very well the ship,
and were probably not in condition to 'squeeze' the best out of it, while the pilots in the local planes of course
knew them 'like their pockets' : put a Saburo Sakai in the cockpit and the zero would had performed better in
climbs and turns!

I don't suppose that Eddie Sanders being the Assistant Flight Test Officer at Anacostia NAS might imply that
he knew a little bit about how to wrest the available performance out of an aircraft? Flight Test was where
USN aircraft types were put through their paces prior acceptance. Sanders was in charge of testing
fighter types. Further, when #4593 was tested against the F4F and the F4U, Sanders was flying the USN
types. Flying the A6M2 was Cdr Fred Trapnell ("Mister Test Pilot") who was head of Flight Test, was USN
jet pilot # 1, established the Naval Air Test Center at Patuxent NAS, and started the test pilot school there.
And our unidentified USAAF pilots from Eglin Field? What do you suppose was their unit mission? Having
had some exposure to USN test pilots (plural) from that era, I would observe that these are not average
pilots, but rather some folks who really knew what they were doing and were very serious about it.

All this, specially if you read the comparison with the F4F where no numbers are given but just a kind
of concerned statements (..zero was superior in speed and climb at all altitudes above 1000 ft .. superior
in ceiling... no comparison between the turning circles... in combat F4F is basically dependent in mutual
support..) states that at the end of 1942 the zero model 21 was at least a terrible customer for the US planes,
and that the new generation of US fighters (Corsair) was better than the Zero.

When you re-read the Summary #85 report you should be able to ascertain that it is a USAAF document.
It clearly states that it presents the information from the Eglin AAF Proving Ground Group (the USAAF
equivalent of the USN Flight Test group at Anacostia NAS) addressing test conducted with the A6M2 against
the P-38, P-39, and P-51 in detail. Small wonder that the information on the tests with those particular
aircraft are in greater detail as the Summary was to be issued to USAAF squadrons. The information on
tests against the F4F and F4U is merely summarized as those are not USAAF aircraft. The service politics
are obvious. While there were USN squadrons that operated P-51s, and even Spitfires, I can't think of any
USAAF squadrons that operated F4Fs or F4Us.

What was not highlighted is the fragility of the zero in sustaing battle damage.

This was something they already knew and appears in debrief reports. For example, I have debrief interviews
from Lt Cdr John Thach and Lt Noel Gayler made at BuAer in the summer of 1942 that clearly note the interesting
phenomena when one's rounds strike home on Japanese aircraft, generally, and A6M2s, specifically.

The problem of the japanese fighter is that it was not substantially improved in the following 3 years,
with an evolution path similar to her western counterparts (because of HQ policy? because the structure could
not hold more power and weight? because no better engines were available?), making it completely
obsolete by 1943.

True. What most tend to forget is that the A6M was originally designed to face the enemy the Japanese were
facing in China, both in terms of aircraft types and in the tactics and quality of the tactics employed by
the Chinese. Once the initial conquering rush, against mostly ill-prepared and ill-supplied adversaries, was
over and it became markedly difficult for the Japanese to marshal overwhelming numbers at any
particular point, coupled with finally better supplied and better prepared adversaries who were not flying
Russian cast offs or using, such as they were, Chinese tactics, it became a different ballgame. The A6M
series design really did not lend itself to many improvements and was, as Syscom3 eruditely noted, a
evolutionary dead end.

Regards,

Rich

 

[FLYBOYJ]

Rich, you are truly amazing!

 

[evangilder]

Another great post Rich. The pictures are outstanding!