How bad would a Euro-spec A6M Zero be?

[Shortround6]

If they could get the A6M8 into play by early 1942 how does it compare against the best possible Spitfires over Darwin.

They can't, the engine isn't quite ready yet.
While they didn't stick the engine into the A6M8 until 1945 the engine was ready earlier, It was used in the D4Y3 starting in May of 1944 and might have been used a bit earlier?
But not 1942. Lower powered versions were used.

 

[FLYBOYJ]

They can't, the engine isn't quite ready yet.
While they didn't stick the engine into the A6M8 until 1945 the engine was ready earlier, It was used in the D4Y3 starting in May of 1944 and might have been used a bit earlier?
But not 1942. Lower powered versions were used.

And I also think engines were changed because of the factory being bombed if I recall. When this model of the zero was first developed it also had engine heating issues as well.

 

[PAT303]

This is where you get it wrong: it haven't ended the war with 'basically the same guns it started [with]'.
The Type 99-2 was more powerful, heavier and bigger than the 99-1. It fired more powerful ammunition, it carried much more rounds. The 13mm HMGs installed were not the 7.7mm guns.

In 1945 it had guns the European fighters had in 1941-42, the ''upgraded'' 13mm guns were the equivalent of the medium velocity .5 Vickers the RAF tested back in the late 1930's and deemed to be not worth the effort, the Spitfire Tempest Typhoon and most likely the P47 P51 had by 1944 armor proofed against the MG151/Type 99-2 AP rounds yet the A6M didn't have armor proofed against any of the Allied in service ammunition like M8 API and SAPI's would just cut right through it, from what I can find out no A6M variant went much over 350mph which is pretty useless when every single plane you will be facing can do 440-450mph and have 500mph+ all with good pilot control. A Euro spec A6M, it's not happening.

 

[PAT303]

They can't, the engine isn't quite ready yet.
While they didn't stick the engine into the A6M8 until 1945 the engine was ready earlier, It was used in the D4Y3 starting in May of 1944 and might have been used a bit earlier?

It's all too little too late, the Japanese boxed themselves into a corner with the design, personally I don't understand why they didn't recognise the need for continual development of newer fighters, like the Germans they were arrogant I guess and thought everyone would give in, the BoB should have taught them that was not the case and given them a glimpse of future airfighting.

 

[Shortround6]

the ''upgraded'' 13mm guns were the equivalent of the medium velocity .5 Vickers the RAF tested back in the late 1930's and deemed to be not worth the effort

The Japanese used a copy of the German 13mm MG 131 as a flexible gun out the back of a few aircraft. A bit less powerful than the .5 Vickers.
HOWEVER, the Zero used a copy of the big Browning chambered for the Hotchkiss 13.2mm X 99mm round. You take the US .50 cal round (12.7mm) and neck it up to 13.2mm.
Bullets are a little heavier, velocity a little lower.

Some Zeros had one in each wing and one in the cowl in addition to the 20mm cannon in each wing.

the Spitfire Tempest Typhoon and most likely the P47 P51 had by 1944 armor proofed against the MG151/Type 99-2 AP rounds

Not sure the Japanese had an AP round for the 99-2 cannon. A better way to look at it is that fired 20mm Hispano HE rounds at 750 m/s. Kinetic energy was about 24% higher than the MG 151.
And no, nobody was carrying armor "proofed" against such 20mm projectiles. The armor they were carrying may have worked pretty well against shells that had to penetrate a certain amount of aircraft structure and/or "stuff" (radio gear?) before it hit the armor plate.

 

[tyrodtom]

The A6M2 had 1x 38 USgal fuselage tank (that weighed 22 lbs), plus 2x 51 USgal wing tank (that weighed 24 lbs each) for a total fuel load of 141 USgal. The tanks were non-SS and were welded aluminum with anti-slosh baffles. They were not integral to the structure (ie they were not a "wet wing" type) and they were designed to be replaceable.

The most common type of SSFT used on UK aircraft (Hurricane, Spitfire, Mosquito, Lancaster to name a few) for most of the war, was the CIMA type (manufactured by FPT and others). It was a .5" thick multi-ply laminate applied over the outside of a metal tank, weighing about .96 lbs/ft2.

The A6M2 fuel tanks were approximately the following size (I looked for accurate dimensions but did not find any, so I approximated from the cut-aways and blueprints I did find.)

The 38.0 USgal tank was about 1.36' x 1.5' x 2.5' which equals a volume of 5.1 ft^3 and a wall square footage of 21.8 ft^2
Each 51.5 USgal tank was about 1.00' x 2.2' x 3.2' which equals a volume of 6.9 ft^3 and a wall square footage of 24.9 ft^2

NOTE that 1 ft^3 = 7.48 USgal by volume

1 x 38.0 USgal 21.8 ft2 x .5" x .96 = 10.5 lbs added weight
1 x 51.5 USgal 24.9 ft2 x .5" x .96 = 12.0 lbs added weight
1 x 51.5 USgal 24.9 ft2 x .5" x .96 = 12.0 lbs added weight

The .5" thickness would also reduce the dimensions of the metal structure and the volume of the tank by an amount proportionate to the square footage of the tank walls, so:

1 x 38.0 USgal = 5.1 ft3 - 21.8 ft2 x .5" x 12"^2 / 12"^3 = 0.91 ft^3 yielding a reduction in volume of 6.8 USgal
1 x 51.5 USgal = 6.9 ft3 - 24.9 ft2 x .5" x 12"^2 / 12"^3 = 1.04 ft^3 yielding a reduction in volume of 7.8 USgal
1 x 51.5 USgal = 6.9 ft3 - 24.9 ft2 x .5" x 12"^2 / 12"^3 = 1.04 ft^3 yielding a reduction in volume of 7.8 USgal

The increase in weight due to the SSFT materials would be about 34.5 lbs and the decrease in fuel load would be 22.4 USgal.
Fitting the same amount of armor as the 1941 Spitfire carried would add about 150 lbs.
Adding a more capable radio such as the TR.1133 would add another 30 lbs or so.
Increase in weight due to the SSFT, armour, and radio, would be 34.5 + 150 + 30 = 215 lbs.
Decrease in weight due to reduction in fuel load would be 22.4 USgal x 6 lb/gal = 135 lbs.

Net change in TOGW would be 215 - 135 = +80 lbs.

So the increased TOGW would be 5335 + 215 - 135 = 5415 lbs, while the wing loading at combat weight would only increase by about .9 lb/ft^2.

Decrease in range would be significant, at a bit over 22.4 / 141 = 16% or about 200 miles, leaving a range of 1000 miles at 250 mph TAS/200 IAS (max economic cruise at 15,000 ft), with enough fuel for 20 minutes of combat (max power) and 30 minutes reserve (at best economic cruise).

In addition to the above weight increases you would probably have to strengthen the underlying metal structure of the fuel tanks. I do not know how much weight this would add to the above calculations, but I doubt it would be more than 50-60 lbs (That is just a guestimate on my part, as I am not familiar with the structure required to withstand the forces imposed on the tank by the impact and penetration of the projectiles).

The A6M3 had a TOGW of ~5500 lbs and according to the US, Australian, and UK tests, it was still ridiculously more maneuverable than the Allied fighters at low-medium speeds so I figure the same mods could be done to the A6M3 with little loss in combat effectiveness.

(I am doing this late at night so let me know if I made any errors. )

edit: The above 1000 mile range is predicated on the maximum range not being limited by the internal fuel load. The fuel load at TOGW would be 141 - 22.4 = 118.6 USgal internal plus the normal 87 USgal DT, for a total fuel load of 118.6 + 87 = ~205 USgal.

In your math equation to see how much weight is added to a tank by the self sealing material it was .96 lb per square foot.

Why in each equation to find that weight did you add a .5 ?

 

[Admiral Beez]

I agree, the lack of a more powerful engine seriously limits what can be done to upgrade the Zero.

Did other radial fighters of 1940-41 have SSFT and cockpit armour? Maybe the latter, but not the former? Perhaps it's unrealistic to expect SSFT on anyone in 1940-41? This P-36 below has armour for the pilot's back.

Same with this MB.152

I'm thinking our heavier Zero is now equal to about the P-36, Bloch MB.152, Re.2000 and early F4F. Heavens.... would it be as bad as the Buffalo?

 

[PAT303]

The Japanese used a copy of the German 13mm MG 131 as a flexible gun out the back of a few aircraft. A bit less powerful than the .5 Vickers.
HOWEVER, the Zero used a copy of the big Browning chambered for the Hotchkiss 13.2mm X 99mm round. You take the US .50 cal round (12.7mm) and neck it up to 13.2mm.

I'm getting my guns mixed up, it's the type 97 that was the Vickers .5?.

And no, nobody was carrying armor "proofed" against such 20mm projectiles.

The RAF aircraft after from 1944 were definitely proofed against German 20mm AP ammunition, I have a document that I will have to find that explains it.

 

[ThomasP]

Hey tyrodtom,

Thank you very much for pointing out my error of incorporating the x.5 factor in the added weight calculation for SSFT materials. I have now corrected that calculation and changed the resulting total weight increase from 34.5 to 69 lbs. I have also corrected all the values in the subsequent posts (I think) that were a result of the incorrect value.

 

[ThomasP]

Hey PAT303,

The 7.7mm Type 97 carried by all A6M models was a detail modified version of the Vickers E .303 cal. The projectiles were (I think) pretty much the same as the UK .303 cal. MV was 2440 ft/sec and ROF was 900 rpm.

The 13mm Type 3 carried by the later A6M5 was an adaptation of the Browning .30/.50 cal design. Although it said 13mm in its name it actually fired the modern 13.2mm Hotchkiss type projectiles (similar to those used by the Italians, including the HE round) with a MV of 2600 ft/sec and ROF of 800 rpm.

As far as I know the A6M never carried an actual .5"/.50 cal MG or 13mm MG.

 

[PAT303]

Hey PAT303,

The 7.7mm Type 97 carried by all A6M models was a detail modified version of the Vickers E .303 cal. The projectiles were (I think) pretty much the same as the UK .303 cal. MV was 2440 ft/sec and ROF was 900 rpm.

The 13mm Type 3 carried by the later A6M5 was an adaptation of the Browning .30/.50 cal design. Although it said 13mm in its name it actually fired the modern 13.2mm Hotchkiss type projectiles (similar to those used by the Italians, including the HE round) with a MV of 2600 ft/sec and ROF of 800 rpm.

As far as I know the A6M never carried an actual .5"/.50 cal MG or 13mm MG.

Sorry mate I'm getting guns mixed up, the Breda appears to be the Italian version of the .5 Vickers the Type 97 the .303.

 

[tomo pauk]

In 1945 it had guns the European fighters had in 1941-42, the ''upgraded'' 13mm guns were the equivalent of the medium velocity .5 Vickers the RAF tested back in the late 1930's and deemed to be not worth the effort, the Spitfire Tempest Typhoon and most likely the P47 P51 had by 1944 armor proofed against the MG151/Type 99-2 AP rounds yet the A6M didn't have armor proofed against any of the Allied in service ammunition like M8 API and SAPI's would just cut right through it, from what I can find out no A6M variant went much over 350mph which is pretty useless when every single plane you will be facing can do 440-450mph and have 500mph+ all with good pilot control. A Euro spec A6M, it's not happening.

So instead of saying 'I was wrong' for the claim that Zero's guns at the end of the war were basically the same as when it was introduced, you prefer to move the goal post.
Not the 1st time someone tried to do it on this forum.

 

[Shortround6]

Did other radial fighters of 1940-41 have SSFT and cockpit armour?

It doesn't matter what engine type.
1940-41 is a very long time.
All sides started in Sept 1939 with very few aircraft carrying armor. It was being installed in new aircraft and retro fitted to existing aircraft over the 1939/40 winter. At least pilot seat back armor which was fairly easy to do. One or more plates in an area not to hard to access (pull the pilots seat if need be), and close to the center of gravity. SSFT were more difficult. But any plane that could have it's tank/s replaced instead of worked on in place could be modified.
By the end of the BoB most first line British and German fighters had at least some armor and some self sealing tanks (Spit got the upper fuselage tank SS very late in the war, if ever?)
US observing what was going on didn't retro fit many planes but insisted on protection on new builds and designated already built aircraft as either trainers or "R" restricted not for combat, this was before the end of 1940.

Heavens.... would it be as bad as the Buffalo?

No.......................
BTW the Buffalo fuel tanks were made by sealing off part of the main spar. Very difficult to work on. So they sealed off one tank and added 3 small SS tanks to make up the difference.

A lot of planes (mostly Russian but some Japanese and few American ones early) didn't use self sealing, they filled the tanks with inert gas to reduce/eliminate the fire hazard. Thr tanks were "protected" but not self sealing. Some authors get a little sloppy with descriptions. I believe at least one model of the US Buffaloes used a CO2 bottle to displace air in the fuel tanks.

 

[Admiral Beez]

The 7.7mm Type 97 carried by all A6M models was a detail modified version of the Vickers E .303 cal. The projectiles were (I think) pretty much the same as the UK .303 cal. MV was 2440 ft/sec and ROF was 900 rpm.

The 13mm Type 3 carried by the later A6M5 was an adaptation of the Browning .30/.50 cal design. Although it said 13mm in its name it actually fired the modern 13.2mm Hotchkiss type projectiles (similar to those used by the Italians, including the HE round) with a MV of 2600 ft/sec and ROF of 800 rpm.

As far as I know the A6M never carried an actual .5"/.50 cal MG or 13mm MG.

Top marks on the in-house design and for its time the Nakajima Sakae, but the Zero is a hodgepodge of foreign tech. British and US-origin machine guns, Swiss/German-origin cannons and US-origin propeller.... and yet they relied on domestic design, manufacture and shielding of its radio. Just buy some German radios FFS. Though a German radio will need some mods before it can serve a naval fighter like the Zero.

"The workmanship is very good. However, the equipment as a whole will not meet our requirements which we impose on our commercial equipment with respect to performance under various temperature and humidity conditions. The German equipment will not pass our tests for operational characteristics over a temperature range from -40° to +150° F. Furthermore, since the various metallic surfaces of the German equipment were not protected against corrosion, it could not pass our standard humidity test. In this connection, it should be noted that none of the coils are impregnated with a protective coating of wax; our standard humidity tests would certainly render the equipment inoperable, if not wreck it."

Maybe the US or Brits will sell a radio design to the Japanese in the late 1930s before the embargos came in.

 

[PAT303]

So instead of saying 'I was wrong' for the claim that Zero's guns at the end of the war were basically the same as when it was introduced, you prefer to move the goal post.
Not the 1st time someone tried to do it on this forum.

Well from what I could find only the A6M5c was up gunned so out of all the variants of the Zero fighter just one model that came out 6 months before the war ended had heavier armament than what it started with and so good was it most ended up being used as Kamikazes because it could carry a bomb, so yes I was wrong, happy now.

 

[ssnider]

if remember correctly the typical cruise speeds in the ETO were higher than the PTO. I think the 1000 mile range for the A6M2 was at about 200 mph. If forced to cruise at 275 or even 250 mph to survive, the range would likely fall into the FW 190 realm.

 

[Shortround6]

I believe the early Zeros carried 55-60 rounds per 20mm gun, 99-1, which fired a 128 gram projectile at 600m/s with a rate of fire of 520rpm
A6M3 got 100 rounds per gun for the 99-2 cannon, which fired the same projectile at 750m/s with a rate of fire of 490rpm. Since impact energy goes up with the square of the speed. there was a roughly 50% increase in kinetic energy. I would say that a more powerful cannon with 40% more ammo was an improvement in armament.

After 747 Zero 52s were built the 52a appeared with belt fed 20mm cannon with 125 rpg. still two 7.7mm machine guns in the cowl
391 of the 52a's were built. Then came the 52b in which one of the cowl 7.7mm guns was replaced by the 13.2mm gun. about 470 built.
The 52c had the fuselage 7.7mm gun taken out and one 13.2mm gun added to each wing.
The gun armament was retained on the A6M7.
The two prototype A6M8s had the fuselage 13.2mm gun taken out to help make room for the bigger engine.

Well from what I could find only the A6M5c was up gunned so out of all the variants of the Zero fighter just one model that came out 6 months before the war ended had heavier armament than what it started with and so good was it most ended up being used as Kamikazes because it could carry a bomb, so yes I was wrong, happy now.

One model????

BTW the A6M7 (with the bomb) was initially developed because the D3A-2 was too slow and poorly armed to make a viable strike aircraft and the D4A-3 had too high a landing speed to operate safely from the smaller carriers the IJN was forced to use in late 1944.
The A6M7 had wing mounted drop tanks to keep the centerline clear for the bomb. A reinforced vertical stabilizer to allow a bit higher dive speed was used. The A6M5 series had introduced heavier wing skins during it's run to allow for higher dive speeds.
What was planned and what the planes were used for a number of months late are two different things.

 

[ThomasP]

Hey ssnider,

Range for the A6M5 with DT (238 USgal total) was ~2298 miles at at v for best range of 205 mph TAS at 13,000 ft in Lo SC gear (no combat or reserves) - from: TAIC Report No.38 April 1945 'Comparative Performance Between Zeke 52 and the P-38, P-51, P-47'

Range for A6M2 with DT (227 USgal total) was 1960 miles at 200 mph TAS at 15,000 ft (no combat or reserves) and about 1650 miles at 250 mph TAS at 15,000 ft (no combat or reserves) and 1200 miles (with 20 min combat and 30 min reserve) - from post-WWII intel report, but I do not have a copy to post (it went away when my last computer died) or remember what the title was. sigh . .

 

[PAT303]

BTW the A6M7

Mitsubishi Reisen (Zero-Fighter) A6M7 Model 63 ZEKE | National Air and Space Museum production started in May 1945 and it was a dive bomber not a fighter so doesn't fit the narrative of the conversation.

 

[ssnider]

only data I am aware of for range vs speed I am aware of:
Zeke 32 (Hamp) 102C (wwiiaircraftperformance.org)
Zeke 52 TAIC 102D (wwiiaircraftperformance.org)