why is the A6M Zero's lack of armor emphasized so heavily

[Shortround6]

Doesn't the Fw 190 have four guns within the propeller arc, counting the two inboard wing-guns?

Sort of, P-38s outboard guns are about 20in apart. FW 190 used a 52in dia cowl,

Wing root guns were around 6 ft apart, better than guns outside the propeller arc but not at all the close spacing of the guns on a V-12 powered fighter.
Germans used electrically primed ammo to make synchronization easier and less loss of rate of fire.
109s used normal primed 20mm ammo with a complication in ammo supply/logistics.

How about a Hurricane IIB or IIC? Wing guns on a P-39?

P-39 fuselage was small compared to P-47. Inner P-47 guns were 47.7in below the line of sight.
F4U was pretty bad.
P-47's inner most guns were just about 18ft apart.

 

[Steamed_Banana]

• Gyro gunsights increased strike rates, particular at longer ranges, by as much as 500%. So a 2.5% hit rate goes up to a much more significant 12.%
• These were used by USN (and RN?) AAA guns and greatly improved accuracy there as well. They were found to be of critical value vs. Kamikaze in particular
• Aerial gunnery training was very lacking by the Allies in many Theaters during the early years of the war
• This was gradually improved through the war (one of the reasons why the importance of high speed target tugs is debated in recent threads on here)
• It seems pretty clear that the unusually high standard of gunnery training by US navy pilots during their early engagements (and continuing through the war) is a major reason why the F4F was able to hold it's own with the A6M,
• Accurate gunnery -and at ranges up to 250 meters- was also one of the key aspects of the Thach Weave tactic successfully employed by F4F and other US Navy pilots from Midway onward.
• The biggest problem in gun accuracy for fighters was not range per se but rather deflection shooting against a maneuvering target. Enemy aircraft rarely flew strait and level for a long time unless they A) already had separation and B) had a reasonably high expectation of being able to out run or out dive or maybe out-climb their opponent, or C) were unaware they were under attack. If they were aware even when trying to out run a pursuing enemy they still flew evasive patterns like slipping or rolling and 'reversing' small turns repeatedly to throw off enemy aim, or flew in spirals etc (like when evading in a shallow high speed climb).
• Gyro gunsights helped a great deal with deflection shooting in particular.
• It's also important to keep in mind that from roughly 1936-1942 guns on aircraft, particularly in the wings, were very vulnerable to jamming, (especially while maneuvering / pulling G) which was effectively another major limitation to accuracy, as often only the first burst would even fire. Some fighter guns could be fairly quickly and reliably manually or electrically cleared by the pilots, some could not. One reason why nose mounted guns were liked by many pilots is because the charging handles extended into the cockpit allowing them to be manually cleared when they jammed.
• I think this is yet another reason why many Soviet fighters used nose guns.
• Rates of jamming gradually improved for Allied fighters from mid-1942 but this was still a problem for some types well into 1944. For example, the 12.7mm wing guns on the P-51B/C had serious issues with jamming until the configuration of the gun was changed on the P-51D
• Other types which were chronically prone to stoppages or jams included the German MG 131 13mm HMG and Mk 108 30mm cannon, the French / British / American Hispano 20mm, the Japanese Ho-5 20mm, and the US 37mm M4 on the P-39
• Many early fighters in WW2 had very limited ammunition. Particularly for the 20mm cannons, the A6M2, Bf 109E, and Spitfire Mk VB all had a limit of 60 rounds each for their 20mm cannon. Also the French made fighters like the Dewoitine D.520, the (otherwise very promising) British Westland Whirlwind and many others. Most Soviet planes continued to have very limited ammunition capacity late into the war, especially for cannon and heavy machine guns.
• This partly helps explain why the Soviets used to train their pilots to shoot from almost point blank range.

I do think that nose mounted guns (and in particular, hub cannon) were much more accurate than wing mounted, though the latter often brought more bullets to bear if shooting accuracy was good, and was clearly best for strafing ground targets, and could be better for shooting down bombers (though clearly accurate nose mounted guns were very good for this too with the right training).

 

[wrathofatlantis]

Now I'm super confused, weren't A6M achieve significant domination over F4F at start of the war due to having superior turn rate?. And that only start to change once F4F started to use boom and zoom tactic.
The F6F that introduced later on and successful achieve 20-1 kill ratio over the Zero also has worse turn rate than F4F and Zero.
What you are telling me is that they all used boom and zoom from the start and Zero could have dominate till end of the war if the pilot were trained to turn fighting instead?

Credit has to be given to the US Navy that it was never dogmatic against turns, and this from the very start. The Japanese were dogmatic against turns, hence the USN pilot quote above.

Boom and Zoom is a pre-War 1930s idea. That is where those twin-engine heavy fighters came from. They literally thought these things could Boom and Zoom their way out with the heavy nose firepower...

The problem is, you need point-blank range to get out of the 2% hit zone, and that means the overtaking is too slow for the Zoom part.

At 24 square metres, the F4F Wildcat has a larger wing than the Ta-152H... The F6F at 31 square metres had the largest single engine fighter wing of WWII (P-47N still a distant second at 28 square metres).

Note that Sakai in his A6M2 barely gains (if at all) by turning with the Wildcat, and is forced to use a loop to finally get behind it...

The later 5 gun Zero could barely beat the Hellcat in turns (maybe), and the early War Zero pilot was probably the most heavily indoctrinated against Turns, as Justin Pyke discovered (to his surprise)...

Still, I doubt the Hellcat had 19:1 over Japanese types. The Corsair is claimed to have had 11:1.

In Osprey's "Corsair vs A6M", the author examined both Japanese and US sources, using strict "failed to return" data in fights where no other types were present: In the entire 1st year of the Corsair (up to March 1944), the Zero and Corsair were 1 : 1 air to air. (No accidents or flak mixed in.)

One of the top Corsair aces had 11 kills, including 8 Zeros. He lost 5 airframes to do that, 3 of them air to air: That is 2.6 :1 on Zeros, but about 3:1 overall.

Decide for yourself if 19:1 for the Hellcat sounds plausible...

The Zero could never have dominated with its put-putting 20 mms, and these, along with bad radios, were its biggest liabilities. But the last 1500 Zeros made, with an extra 3 X 13mms (+250 pounds), plus using turning tactics, certainly would have taken a much bigger bite than the early ones did.

That is honestly go opposite of everything I ever read about WW II combat. I mean literally the only program which seemingly produce lighter fighters than previous version are the XP-51J, XP-51G and XP-51F. The rest seem to emphasize speed over agility

It is true the engineers kept adding power to the prop fighter concept...

But it is also true that, by 1945, using 60% power, flaps, and turning all the time, all this was becoming normal. One anecdote really illustrates the point:

I forget the name of the pilot, unfortunately, but he was a 190A-8 pilot fighting in 1945, almost exclusively at low level... A painter presented to him a painting of his aircraft in combat with the wings level, close to a snowy scene that was on a specific date.

He had the painter re-do the painting... This is what he said, I kid you not: "Our wings were never level in combat. We turned all the time, without interruption. By 1945 we were so outnumbered, it was the only way to survive."

Again, it is up to you if you want to go with that, or go with descriptions of "energy fighting" by boomer historians.

 

[Greg Boeser]

Credit has to be given to the US Navy that it was never dogmatic against turns, and this from the very start. The Japanese were dogmatic against turns, hence the USN pilot quote above.

Boom and Zoom is a pre-War 1930s idea. That is where those twin-engine heavy fighters came from. They literally thought these things could Boom and Zoom their way out with the heavy nose firepower...

The problem is, you need point-blank range to get out of the 2% hit zone, and that means the overtaking is too slow for the Zoom part.

At 24 square metres, the F4F Wildcat has a larger wing than the Ta-152H... The F6F at 31 square metres had the largest single engine fighter wing of WWII (P-47N still a distant second at 28 square metres).

Note that Sakai in his A6M2 barely gains (if at all) by turning with the Wildcat, and is forced to use a loop to finally get behind it...

The later 5 gun Zero could barely beat the Hellcat in turns (maybe), and the early War Zero pilot was probably the most heavily indoctrinated against Turns, as Justin Pyke discovered (to his surprise)...

Still, I doubt the Hellcat had 19:1 over Japanese types. The Corsair is claimed to have had 11:1.

In Osprey's "Corsair vs A6M", the author examined both Japanese and US sources, using strict "failed to return" data in fights where no other types were present: In the entire 1st year of the Corsair (up to March 1944), the Zero and Corsair were 1 : 1 air to air. (No accidents or flak mixed in.)

One of the top Corsair aces had 11 kills, including 8 Zeros. He lost 5 airframes to do that, 3 of them air to air: That is 2.6 :1 on Zeros, but about 3:1 overall.

Decide for yourself if 19:1 for the Hellcat sounds plausible...

The Zero could never have dominated with its put-putting 20 mms, and these, along with bad radios, were its biggest liabilities. But the last 1500 Zeros made, with an extra 3 X 13mms (+250 pounds), plus using turning tactics, certainly would have taken a much bigger bite than the early ones did.





It is true the engineers kept adding power to the prop fighter concept...

But it is also true that, by 1945, using 60% power, flaps, and turning all the time, all this was becoming normal. One anecdote really illustrates the point:

I forget the name of the pilot, unfortunately, but he was a 190A-8 pilot fighting in 1945, almost exclusively at low level... A painter presented to him a painting of his aircraft in combat with the wings level, close to a snowy scene that was on a specific date.

He had the painter re-do the painting... This is what he said, I kid you not: "Our wings were never level in combat. We turned all the time, without interruption. By 1945 we were so outnumbered, it was the only way to survive."

Again, it is up to you if you want to go with that, or go with descriptions of "energy fighting" by boomer historians.

You cannot use a quote like that to insist that circle fighting was the only way to win. Of course, the german pilot had to keep turning! Flying straight and level meant somebody was going to hop on your tail and shoot you down. Defensive turns increased the difficulty of a shooter. But he didn't just fly in a circle. He flew a constantly changing flight path. Flying in a circle is predictable. This is why the Lufbury circles flown by the RAF in North Africa were so easily exploited by people like Marsaille.

 

[Steamed_Banana]

You cannot use a quote like that to insist that circle fighting was the only way to win. Of course, the german pilot had to keep turning! Flying straight and level meant somebody was going to hop on your tail and shoot you down.

Agreed, turning doesn't necessarily mean pulling G / combat maneuvering

Defensive turns increased the difficulty of a shooter. But he didn't just fly in a circle. He flew a constantly changing flight path. Flying in a circle is predictable. This is why the Lufbury circles flown by the RAF in North Africa were so easily exploited by people like Marsaille.

Lufbury circles were indeed exploited by Marseille, but according to the German pilots in his unit (JG 27), his ability to do so was almost unique. The tactic, while a long way from ideal, could be effective when used correctly. DAF did eventually use it much more effectively (in combination with "Big Wing" tactics) in the Western Desert, and it was also used successfully by Ki-43 pilots to cope with energy fighting tactics from faster Allied fighters in Burma and New Guinea.

 

[wrathofatlantis]

You cannot use a quote like that to insist that circle fighting was the only way to win. Of course, the german pilot had to keep turning! Flying straight and level meant somebody was going to hop on your tail and shoot you down. Defensive turns increased the difficulty of a shooter. But he didn't just fly in a circle. He flew a constantly changing flight path. Flying in a circle is predictable. This is why the Lufbury circles flown by the RAF in North Africa were so easily exploited by people like Marsaille.

Precisely the wrong conclusion. That becomes obvious when you study this for thirty plus years.

Do you think these guys were worried about circles being predictable?:

Clayton Gross, P-51 ace:
"I had a ten minutes turning battle with a Me-109. Hard to say if I was a little better than him, or the machine was a little better, but I slowly gained over about 70 to a hundred circles."

P-51D ace Joe H. Joiner: "Who can out-turn the other will win the air battle."

You are trying to visualise in your mind how this would work. Yes, you could trash about before the circle was locked-in.

The problem is you can't visualise how the circle locks you in. But it does lock you in: Some WWII pilots have described it in these exact terms.

You don't even know that very basic thing.

And please forget how jet pilots describe turn-fighting: They obviously don't have the slightest clue how it works for props.

As soon as you hear "energy" in a WWII context, you know the tactics discussion is a goner.

 

[Greg Boeser]

I've read enough pilots' descriptions to know that maneuver combat - be that dogfighting, a furball, or whatever, is a chaotic experience that can't be distilled to one size fits all bromides. The pilot who shot down Klaus Mietusch, a Luftwaffe veteran with over 70 kills, describes a very wild chase, involving all sorts of maneuvers and stunts. But, you will say, if only he had turned in a circle.
No.

 

[Steamed_Banana]

Some first hand combat descriptions from Shores Bloody Shambles Vol III. I'll let the reader decide if this describes exclusively low speed turn fighting in a circle or 'energy fighting'

2/Lt William W. Fetner , P-38 pilot, November 4, 1944

"We were at 14,000 feet and just before the 'Libs' [B-24s] went on the bomb run, the Zeros [sic] hit us. I was the 'tail end Charley' in our flight and right after we dropped our belly tanks and shoved the throttles forward, I found myself way behind because I was flying an old 'H' model and the other guys had 'Js'. I couldn't pull as much manifold pressure. My right engine was detonating and smoking and i wasn't sure whether it was going to hold out.

Anyway, imagine my surprise to see a Zero in front of me shooting at the rest of the flight. I called Wood immediately to hit the deck, but the Zero kept right on following them and was not closing the gap very fast so I let him have a long burst and I saw my tracers going all around him and off came his right wingtip or aileron. He immediately did a split 'S', I only hope my film comes out Ok becaue I know he's damaged.

Well I'm still trying to catch up with my flight when I look around (my head had to be on a swivel) and there sits a Zero coming like mad at me. Naturally, I dump the nose and I soon lose him in the mad rush. I climb to join my flight again and as I'm closing the gap, another Zero dives down on my flight and I've got another shot. Even though he is out of range, I let him have the 50's and cannon because he is spraying the flight with lead. My tracers go all around him and he makes a sling shot 180 turn (damn those Zeros can turn) to the left and we almost make a head-on collision. We passed so close that I could see the facial features of the pilot in the cockpit and he was grinning like a monkey.

Well I go on trying to catch up and somebody yells over the horn that a Zero is on my tail. I look in the mirror and see two cannon in the wings winking red at me [this may be a Ki-84]. Down I go again. I dive into some clouds and lose him but as I come out, another Zero drops on me and I am just about to catch up with my flight when from out of nowhere another one is back on my tail with his guns smoking like crazy. My shoulders are aching from trying to get small behind my armour plate. I look back and see Broadfoot's flight drop on him and then scare him away. It was a classic mad scramble but as I look back it was an awful lot of fun. We could have given them a better fight but Rangoon is so far down and you just can't afford to pull war emergency too long. This sweep lasted five hours and everybody was sweating gas coming home."

P-51A pilot 1st Air Commando Group Capt. Olin Carter, 19 May 1944
(describing an engagement with Ki-43s)

".... I followed him. I got fairly close and gave him a burst. He pulled up very sharply and fire was coming out all underneath the plane and then he fell over. At the time I saw a couple of other Oscars above, so I had to dive out. hen I looked around and rejoined the formation and it was confirmed that I had shot down an Oscar, which was a big thrill for me."

[he apparently shot down and killed Cpl. Kimie Kato of 50th Sentai.]

Hurricane II pilot Flt Lt C.G.H Ditmas from 11 RAF Sqn (this one does sound like at least partly a turn fight, but for specific reasons obvious in the text) describing an attack on three Ki-48s escorted by Ki-43s from 64 Sentai. 26 April 1944

"I have very little difficulty remembering this day. My No 2 called up with engine overheat so he departed and yours truly arrived over Imphal Main the same time as the Japs. They were about 2,000 feet below, crossing left to right, so I tried a rolling attack but no sooner had I started to fire my four cannons than I was hit by .5 fire from their escorting aircraft. Their first burst took away my air-lines to the guns. Of course, I didn't know this at the time, only that a number of unfriendly folk with high powered armament were very close and getting closer. One, a black night fighter, was highly persistent. I had gone into a vertical dive, but could not release my long-range tanks. They were stuck, so my speed was limited and he followed me to ground level, where there began a very lonely, and to me, prolonged battle of wits. The Hurricane was a good gun platform used against troops, tanks and transport, but no match for a Zero. For all of fifteen minutes I flew between, under and almost through trees, hills and occasionally huts. The technique was to fly sideways with maximum slip, and it seemed to work. It's always hard to sight and fire at a twisting target within a few feet of the ground. Add considerable slip and gauging deflection becomes even more difficult. Anyhow, I can vividly recall he tracer passing just to one side, over and over again. I was close enough to hear the rattle of his .5s.

He must have run out of ammo and / or lost me, because suddenly there he was - 20 feet in front and a wing-span to the right. That's when I found I had no air pressure to my guns! He went home and so did I. The landing was officially called a 'crash' but I walked away so it was Ok. "

RAF Spitfire VIII Pilot Flg Off. Alan Pert of 81 Sqn RAF (it was not clear if he was with 81 or 607 Sqn, but one of the two) 17 April 1944, engaging 12 Sentai Ki-21s escorted by 50th, 64th and 204th Sentai Ki-43s

"We were scrambled from the trip on a clear day and I think I was leading B flight of four Spitfires. We climbed hard under instruction from the controller and intercepted a large force of the enemy. There were six bombers at medium altitude, say 15,000 feet, with covering fighters up to 30,000 feet. We positioned ourselves and then attacked the top cover. At high altitude the Japanese aircraft performed poorly in comparison with the Spitfire and they rapidly joined their medium cover fighters. This is where the main combat took place.

The Oscar I claimed destroyed was badly hit and fell out of the sky obviously not under control. It spun, recovered, spun and recovered in that sequence until a gout of flame appeared from the jungle well below. I was assembling my flight for a further attack when one Oscar came from underneath firing at me until he could climb no more and stall-turned away. As we were reassembling I only took evasive action and did not press this further good opportunity.

The Spitfire VIII had a considerable advantage over the Oscars, being armoured, more highly powered, faster, and because of it's two-stage supercharger had the advantage of altitude. They on the other hand were extremely manoeuverable, had greater endurnce in the air, and generally outnumbered the intercepting Spitfires. Our tactics were to position ourselves above the Oscars, attack at speed using the sun, surprise if possible, and power to climb away out of range. Thus we could mount continuous attacks with relative impunity."

That is pretty bloody clear about what tactics used I would say. But draw your own conclusion. It's also clear to me that these pilots are still not exactly fearless when it comes to dealing with the Oscars in their more advanced machines.

This is an excerpt from the same RAF Spitfire MK VIII pilot, Flg Off. Alan Pert, in a letter he wrote to the father of his wingman, Sqn. Leader "Babe" Whitamore, who died in an engagement with 64th Sentai Ki-43s on 17 March 1944. This one (IMO) shows a mix of turn fighting and energy fighting, as the engagement was right over the British airfield at low altitude.

"We had barely got up to 3,000 feet when four Oscars (Army 01s) came shooting over the aerodrome boundary and commenced to strafe the rest of our machines. Plt Off Coulter caught a full burst right in the cockpit and died shortly later. The other three all had miraculous escapes. Both of us immediately turned and dived on the Japas, but could only upset their second strafing run, as we were not in a position to get in an effective burst of fire. We pulled up together, rolled over and made a second attack without success as the Japanese all took evasive action. On our breakaway this time we found ourselves right in the middle of a formation of from 12 to 14 more Oscars. I shall explain our method of attack so you may see how we became split apart.

The breakaway was done by pulling up into a vertical climb and half-rolling to keep the opposition in sight. When maximum height was reached, the machine was pulled onto it's back and half-rolled out. Consequently both of us were caught in a stalled position. Before either of us knew what had happened we had at least three Japs sitting under each of our tails, and hanging on like grim death. I heard your son call out over the R/T, 'Scramble the rest.' And we both went into violent evasive action, and became split up. For a while I didn't see Sqn Ldr Whitamore as the sky seemed full of Japs, but both of us evidently stayed within the vicinity of the aerodrome.

During one part of the melee about a mile away I saw your son come diving down on an Oscar and the machine went down in flames. Immediately after a Jap came streaking down and sat under his tail. I didn't see any more then as I ran into another bunch of Japs and spent the next ten minutes with them. I will now continue the story as it was told to me verbally by an Army officer who saw the actual tragedy.

He said he saw what I have just related, but that the Spitfire seemed to stagger and stalled. It didn't go into a spin but came down in a series of swoops, as though out of control, and just after the pull out from the last one it crashed into the jungle about a mile from the aerodrome."

Shores notes in the text that 136 and 81 Sqn lost three Spitfires, while 4 Japanese Ki-43s were shot down, and that Pert's own aircraft "...landed with the engine bearers broken, extra dihedral on the wings resulting from the violent manuevering, sprung tail rivets, and a shell hole behind the cockpit."

High G turns could put a serious strain on a fighter airframe.

After another combat on 15 February 1944 Spitfire pilot Dudley Barnett from 136 Sqn noted in his diary:

"A bad day, 81 got a completely new opinion of Japs. Reckon ME and UK squadrons would be very surprised. Most of their (81's) aircraft u/s for rippled skins and warped engine bearings! We've a bit of it too."

On 26 Dec 1943, Spitfire pilots from 615 Sqn engaged Ki-43s from 33rd, 64th and 98th Sentais escorting 21 x Ki 21s against Chittagong. Flg Off G.W. 'Bill' Andrews wrote the following in his diary:

"... first saw fighters about 5,000 feet below. Chat (Sgt Chatfield) and I went scooting down, gave one a sharp burst (he was later seen to crash) and pulled back up into the sun. Then saw the bombers covered by swarms of fighters. Had lashings of speed, we dived right through them onto the bombers. Attacked one, saw strikes on him, very narrowly missed ramming him. Chat also got in an attack and from that attack two of them went strait down. We pulled up and climbed into the sun and then repeated the act. Chat got another 'flamer' and mine stayed put though I saw numerous strikeso n him. We got plenty of return fire, and heard a couple hit my kite. Checked my gas and found i would not have enough to climb back at high revs and do it again, so called hat up and said i was going home. He was doing the saem (we had then got separated.). Could see a hole in my wing which I figured was very close to my port tyre, so put her down gently. She swung but managed to hold her strait until I had lost my speed."

He then notes

"I was always struck by the beautiful paintwork and turn-out of the 'Oscars', they looked like beautiful overzsized toys and it was hard to think of them as lethal, but they were, and could out turn us. It was most unwise to tangle with them without a height and speed advantage."

I don't know if that sounds like energy fighting to you, but it does to me.






I would like to be clear that the little commentaries these pilots made about their aircraft relative to the Japanese fighters are their direct quotes and do not come fro me.

 

[Greg Boeser]

One interesting observation from an Oscar pilot. The Ki-43 and the Spitfire could turn at the same rate, the Spitfire's turn was wider due to it's higher speed.

 

[R Leonard]

Still, I doubt the Hellcat had 19:1 over Japanese types. The Corsair is claimed to have had 11:1

Bear in mind that the F6F ratio is total credited victories. Using official USN statistics:

F6F losses are recorded as 270, against fighters, credits were 3718; against bombers and all other types 1445.

I would imagine that starting in mid 1944 a goodly number of the fighter credits were fighters toting bombs but were probably counted as fighters anyway. After all an F6F or an F4U carrying one or more bombs was still considered a fighter.

F4U losses were recorded as 189, against fighters credits were 1660; against bombers and all other types 478; the same caveat regarding fighters carrying bombs might apply.

Both of these types were about twice as likely to be brought down by AA fire as A2A tangling.

 

[skultew]

Returning to the topic of the Zero's armor one of the interesting questions is why the A6M received armor so late.

To summarize what is written in the どうして？で読み解く零戦発達史 about this theme and adding some my thoughts:

According to initial plans IJN wanted to cease Zero production by 1944 switching to the production of new-generation fighters. However due to the failures of the J2M, A7M, and other aircraft these plans were thwarted. And looks like to the desire to stop production of A6M development of new modifications was slowed down.

Therefore urgent work began on improving the Zero and one of the results of which was the A6M5 Hei. It was not developed by Jiro Horikoshi, but by the team of Eitaro Sano, the designer of the F1M2.

In essence, the A6M5 Hei was not a "logical evolution of Zero" but an attempt to bring the performance of an outdated aircraft up to that of a new generation of fighters. Therefore its design incorporated armored glass (front and rear), armored back plate and self-sealing fuel tanks (only planned).

A6M5 Otsu (as the first Zero with armor) got its front armored glass because it was decided to implement some of the solutions from the A6M5 Hei to the A6M5 Otsu due to the almost parallel production.

Self-sealing fuel tanks were planned for the serial production of A6M6c (Model 53) but due to problems with the water-methanol injection system on Sakae 31 this version did not enter production.
Meanwhile A6M5 Hei did not receive self-sealed fuel tanks due to problems with the production of synthetic rubber for the inner rubber layer. (looks like creating fuel tanks with an outer layer required a complete redesign of the tanks and part of the wing which was apparently abandoned due to the urgent need for mass production)

Also there is a certain paradox regarding armor. Many photographs of the A6M5 Hei and A6M7 show the rear armored glass missing. It is impossible to see from these photographs whether the rear armored back plate is present. It is also possible missing.

Photo of A6M5 Hei with armored glass clearly seen and it is the only with it I could find at the moment

Modern photo of A6M7 which clearly shows how cockpit with armored glass should look like

And some examples with clearly missing armored glass

But the front armored glass is present in all photographs.
It is unclear whether the lack of rear armor was due to the pilots' desire to lighten the aircraft (the rear armor were removable and manual clearly stated the stage for removing it) or because the aircraft were already being delivered without rear armor.

Zero was also equipped with automatic fuel tank fire suppression systems (tbh this system is surprisingly rarely discussed despite its widespread use among naval aircraft and even some army aircraft manufactured by Mitsubishi)

Fuel tank fire extinguishers were initially developed in the late 1930s after the fighting in China but entered mass production only in spring of 1943 on the G4M.

A6M5 Model 52 received this system only in December 1943 and it only worked on the wing fuel tanks. Overall according to various literature this system proved quite effective and many squadrons praised its performance and expressed official gratitude to engineers.

However there were complaints that the system did not extinguish the fuselage fuel tank so on A6M5 Otsu also added fuselage fuel tank fire extinguisher.

After activation (in memories of one G4M crew member said that it was activated before combat) this system automatically detected fire and released CO2 for extinguish fire.

A6M5 had two CO2 ballons: one extinguished both left wing tanks another - the right wing tanks (I don't know if a third ballon was added for the fuselage tank on the A6M5 Otsu).

Scheme of automatic fire extinguisher on early A6M5

Photos of CO2 ballons (full green) and system control box in A6M5 from Robert C. Mikesh book (interesting that it is described as engine fire extinguisher bottles but since engine fire extinguishers was deleted from A6M5 and it placed same as on scheme above - it is fuel tanks extinguishers)

The topic of the A6M5 Hei armament was also raised. Although it was standardly armed with three Type 3 13.2mm machine guns sometimes (pretty rare) fuselage Type 3 was removed (can be seen on one of the photo above). And I think it was removed not so much to reduce weight as to free up space in the fuselage.
Type 3 took up a lot of space in the fuselage and possibly it was placed on right side of fuselage to avoid interfering with pilots entering the cockpit from the left.

Rear of Type 3 is clearly visible in cockpit.

 

[elbmc1969]

This is confusing, weren't radial engine supposed to be a lot more resistance to damage compared compared to liquid cooled engine since liquid engine have coolant line and what not?

In addition to Shortround's reply, modern inline engines have a single cylinder head for all of the cylinders in one bank, with a head gasket between it and the block. If an impact cracks the cylinder head, damages the gasket, or what have you, the engine can suddenly have several or all of the cylinders in that bank leaking. This is bad.

In addition, there's a single liquid cooling system for all of cylinders in a bank. If a heavy round hits the engine and cracks it just enough to cause a coolant leak, all of the cylinders will suffer the effect, although the ones in the cracked block will be affected worse.

Radials have the advantage of their cylinders being essentially independent of each other. If you damage one cylinder so much that gas can escape, it doesn't cause other cylinders to leak. In addition, radials don't have cylinder heads that are bolted on.

Of course, the cooling "systems" are just metal fins, so smashing one cylinder has little effect on the cooling of the other cylinders.

The Hispano-Suiza 12Y, being an archaic design, didn't use monolithic cylinders heads. Each cylinder had a head shaped a bit lit a tall drinking glass that slid down the cylinder liner and (IIRC) screwed into the engine block.

 

[MiTasol]

The Ki-84 having the Ho-5 in the wings allowed the full 800 rpm rate of fire, while the Ki-100 had its two 20 mm Ho-5s in the nose, and because Ho-5s were Browning designs, the prop synchronisation dropped the rate to 500-550 rpm... The Ki-84 could be considered to have a firepower advantage because of wing location. This is why Browning .50s rarely if ever fired through the prop in US designs...

P-36, P-39, P-40 early, P-43, etc etc etc.

 

[Greg Boeser]

P-36, P-39, P-40 early, P-43, etc etc etc.

SBD, F2A, Mustang Mk I, A-36, P-35, CW-21, P-66.

 

[NorthEleanor]

Returning to the topic of the Zero's armor one of the interesting questions is why the A6M received armor so late.

To summarize what is written in the どうして？で読み解く零戦発達史 about this theme and adding some my thoughts:

According to initial plans IJN wanted to cease Zero production by 1944 switching to the production of new-generation fighters. However due to the failures of the J2M, A7M, and other aircraft these plans were thwarted. And looks like to the desire to stop production of A6M development of new modifications was slowed down.

Therefore urgent work began on improving the Zero and one of the results of which was the A6M5 Hei. It was not developed by Jiro Horikoshi, but by the team of Eitaro Sano, the designer of the F1M2.

In essence, the A6M5 Hei was not a "logical evolution of Zero" but an attempt to bring the performance of an outdated aircraft up to that of a new generation of fighters. Therefore its design incorporated armored glass (front and rear), armored back plate and self-sealing fuel tanks (only planned).

A6M5 Otsu (as the first Zero with armor) got its front armored glass because it was decided to implement some of the solutions from the A6M5 Hei to the A6M5 Otsu due to the almost parallel production.

Self-sealing fuel tanks were planned for the serial production of A6M6c (Model 53) but due to problems with the water-methanol injection system on Sakae 31 this version did not enter production.
Meanwhile A6M5 Hei did not receive self-sealed fuel tanks due to problems with the production of synthetic rubber for the inner rubber layer. (looks like creating fuel tanks with an outer layer required a complete redesign of the tanks and part of the wing which was apparently abandoned due to the urgent need for mass production)

Also there is a certain paradox regarding armor. Many photographs of the A6M5 Hei and A6M7 show the rear armored glass missing. It is impossible to see from these photographs whether the rear armored back plate is present. It is also possible missing.

Photo of A6M5 Hei with armored glass clearly seen and it is the only with it I could find at the moment
View attachment 883704

Modern photo of A6M7 which clearly shows how cockpit with armored glass should look like
View attachment 883705

And some examples with clearly missing armored glass
View attachment 883706
View attachment 883707

But the front armored glass is present in all photographs.
It is unclear whether the lack of rear armor was due to the pilots' desire to lighten the aircraft (the rear armor were removable and manual clearly stated the stage for removing it) or because the aircraft were already being delivered without rear armor.

Zero was also equipped with automatic fuel tank fire suppression systems (tbh this system is surprisingly rarely discussed despite its widespread use among naval aircraft and even some army aircraft manufactured by Mitsubishi)

Fuel tank fire extinguishers were initially developed in the late 1930s after the fighting in China but entered mass production only in spring of 1943 on the G4M.

A6M5 Model 52 received this system only in December 1943 and it only worked on the wing fuel tanks. Overall according to various literature this system proved quite effective and many squadrons praised its performance and expressed official gratitude to engineers.

However there were complaints that the system did not extinguish the fuselage fuel tank so on A6M5 Otsu also added fuselage fuel tank fire extinguisher.

After activation (in memories of one G4M crew member said that it was activated before combat) this system automatically detected fire and released CO2 for extinguish fire.

A6M5 had two CO2 ballons: one extinguished both left wing tanks another - the right wing tanks (I don't know if a third ballon was added for the fuselage tank on the A6M5 Otsu).

Scheme of automatic fire extinguisher on early A6M5
View attachment 883708

Photos of CO2 ballons (full green) and system control box in A6M5 from Robert C. Mikesh book (interesting that it is described as engine fire extinguisher bottles but since engine fire extinguishers was deleted from A6M5 and it placed same as on scheme above - it is fuel tanks extinguishers)

View attachment 883709
View attachment 883710

The topic of the A6M5 Hei armament was also raised. Although it was standardly armed with three Type 3 13.2mm machine guns sometimes (pretty rare) fuselage Type 3 was removed (can be seen on one of the photo above). And I think it was removed not so much to reduce weight as to free up space in the fuselage.
Type 3 took up a lot of space in the fuselage and possibly it was placed on right side of fuselage to avoid interfering with pilots entering the cockpit from the left.

Rear of Type 3 is clearly visible in cockpit.
View attachment 883711

Amazing information! Your knowledge of the Zero is truly impressive! I think everyone would be interested in learning more about this remarkable aircraft.

 

[mig-31bm]

Yes. The Ki-100 also turn-climbed much better, and probably climbed better.

I just checked and apparently Ki-84 dive and climb better than Ki-100 also
Weird

 

[mig-31bm]

This idea of all air combat between fighters meant dogfighting which inevitably devolved to low speed turn fights seems to mainly derive from Pierre Clostermann's memoir, and he is definitely an outlier. Many other pilots describe dogfighting at middling speeds (200 -250 mph) which seems to be very common in the mid-war (and was part of official tactics for many US fighters) and it's clear that higher speed (300 mph+) passes were also quite routine.

The high speed shooting passes became much more viable (in terms of getting hits) after the advent of the British designed Mk II Gyro-Gunsight, introduced to British fighters in 1943 and then as the K-14 Gyro Gunsight to US fighters in 1944. I think that had a lot to do with the success of higher speed fighting tactics. Improved tracers and 'flash' bullets also helped.

So in your opinion, Allies aircraft often much better than Japanese one in boom and zoom tactic thanks to their gun sight, correct?

I think it was a combination of good performance, good agility and good handling right in a kind of sweet spot balancing the three factors. Plus reliability. A bit like the F6F for the Americans.
Good in most relevant categories vs great in one and poor in another, in other words.

Isn't good agility and good handling basically the samething?

 

[MiTasol]

You didn't want the guns shooting at point of aim when static on the ground, but I suspect that is how many of them were set up...

The AAF manual on gun harmonisation was AAF 200 and I was sure there was a copy on the forum but I cannot find it so here is one version. I had an earlier version but that is gone.

The following is a link to RAF gun harmonisation on the forum

WWII RAF Gun Harmonisation

As mentioned last year: http://www.ww2aircraft.net/forum/aviation/why-did-raf-persist-303-throughout-war-37878.html ... While my article isn't entirely finished and not quite ready for 'prime time', I figured I post my mostly complete write-up as a preview: Gun Harmonisation Love to...

ww2aircraft.net

 

[MiTasol]

So in your opinion, Allies aircraft often much better than Japanese one in boom and zoom tactic thanks to their gun sight, correct?

Isn't good agility and good handling basically the samething?

No - an aircraft can be agile but a pig to fly.

 

[MiTasol]

In essence, the A6M5 Hei was not a "logical evolution of Zero" but an attempt to bring the performance of an outdated aircraft up to that of a new generation of fighters. Therefore its design incorporated armored glass (front and rear), armored back plate and self-sealing fuel tanks (only planned).

Self-sealing fuel tanks were planned for the serial production of A6M6c (Model 53) but due to problems with the water-methanol injection system on Sakae 31 this version did not enter production.
Meanwhile A6M5 Hei did not receive self-sealed fuel tanks due to problems with the production of synthetic rubber for the inner rubber layer. (looks like creating fuel tanks with an outer layer required a complete redesign of the tanks and part of the wing which was apparently abandoned due to the urgent need for mass production).

Adding protection to tanks requires redesigning the tanks some 25-30mm smaller in all dimensions as the covering is typically some 12-15mm thick if they used a similar covering system to what the British used. Wing redesign is relatively minor as all the plumbing is now sitting some 12-15mm higher above the lower skin. Fillers and drains also need attention not just because they have to be extended. On some aircraft (Beaufort and Beaufighter for example) the protected tanks needed additional drains though that might have been a result of operational experience from the tanks sweating and "making" water in humid conditions.

Also there is a certain paradox regarding armor. Many photographs of the A6M5 Hei and A6M7 show the rear armored glass missing. It is impossible to see from these photographs whether the rear armored back plate is present. It is also possible missing.

Photo of A6M5 Hei with armored glass clearly seen and it is the only with it I could find at the moment
View attachment 883704

Modern photo of A6M7 which clearly shows how cockpit with armored glass should look like
View attachment 883705

If you are referring to the smoky colour of the rear glass that is almost certainly the normal discolouration that occurs in clear plastics of that age. I would not expect the rear glass to be curved glass panels as that area of glass would be very heavy. I would expect that the A6M rear glass was either immediately in front or behind the rollover pylon like on allied aircraft as this is not only much lighter but far simpler and cheaper to manufacture
.

But the front armored glass is present in all photographs.
It is unclear whether the lack of rear armor was due to the pilots' desire to lighten the aircraft (the rear armor were removable and manual clearly stated the stage for removing it) or because the aircraft were already being delivered without rear armor.

I would love to see a copy/translation of that process.

However there were complaints that the system did not extinguish the fuselage fuel tank so on A6M5 Otsu also added fuselage fuel tank fire extinguisher.

thank you - I was aware of the wing tank protection but not the fuselage tank issues.

After activation (in memories of one G4M crew member said that it was activated before combat) this system automatically detected fire and released CO2 for extinguish fire.

View attachment 883708

Photos of CO2 ballons (full green) and system control box in A6M5 from Robert C. Mikesh book (interesting that it is described as engine fire extinguisher bottles but since engine fire extinguishers was deleted from A6M5 and it placed same as on scheme above - it is fuel tanks extinguishers)

View attachment 883709

For those interested the mushroom shape above and slightly forward of the CO2 bottles is an anti-chafe for the flotation bag that fills the area when the aircraft is ditched.

The topic of the A6M5 Hei armament was also raised. Although it was standardly armed with three Type 3 13.2mm machine guns sometimes (pretty rare) fuselage Type 3 was removed (can be seen on one of the photo above). And I think it was removed not so much to reduce weight as to free up space in the fuselage. Type 3 took up a lot of space in the fuselage and possibly it was placed on right side of fuselage to avoid interfering with pilots entering the cockpit from the left.

Rear of Type 3 is clearly visible in cockpit.
View attachment 883711

thank you - I had never noticed that before.