The Messerschmitt Bf 109 and the Mitsubishi A6M Zero are remembered as the Axis forces primary fighters in World War 2. Both served from the start of the war until its end. Which was the superior machine?

Notes:

During world war 2, both the Germans and Japanese developed many fighter aircraft. In the multitude of aircraft rolling off the production line, both air forces continued to rely on fundamentally prewar designs; for the Germans, it was the Messerschmitt B-f 1-owe-9, and for the Japanese, it was the Mitsubishi A-6-M Zero. Both aircraft saw service from the beginning of world war 2, through till the very end.

An opinion, often attributed to Japanese fighter ace Saburo Sakai, held that if the Germans had used Zeros rather than B-f 1-owe-nines during the Battle of Britain, then the Germans would have seen greater success in the air. There is no doubt that early in the war, the Zero outclassed much of its competition, but how correct is this opinion?

During the Battle of Britain, 1-owe-9 pilots frequently pulled out of fights early due to fuel shortages. This was noted as one of the greatest limitations on the aircraft.

Whilst the commonly held view is that the Blitz helped the RAF rebuild their Air Force, since Luftwaffe firepower had been redirected towards London, it could also be suggested that if the Germans had aircraft capable of operating for longer during the early stages of the battle, then a swift elimination of all RAF air power could have been achieved. Whether or not this holds any weight is up for debate, but what is often forgotten is just how capable the A6M Zero was during the first half of the war.

It could be argued that during the early days of world war 2 – when the US and Japan first entered the conflict – that the Zero was the most capable aircraft in the skies, outmatching early versions of the 1-owe-9, the spitfire, and any US aircraft operating at the time. So how does the Zero actually compare to the B-F-1-owe-9? In this comparison, we will look at available data, alongside other important factors which defined the performance of both aircraft.

 

COMBAT RECORD

To begin with, lets start with the combat record of both aircraft. The most obvious place to begin is overall kill count. This is where both aircraft differ the greatest; the Zero racked up a total kill count of roughly 1500 aircraft.  In contrast, the BF 109 achieved somewhere around 20,000 aerial victories. Not only does this clearly put the 109 above the Zero, but this kill count is unmatched by any other aircraft ever produced, making the 109 the highest scoring aircraft of all time.

But kills are only one aspect. What about the win loss ratio.

One consideration when looking at this data is that this ratio would have reflected performance better during the early years of the war, and would have been thrown off as both Axis nations collapsed. During the last year of the war, both Germany and Japan were throwing thousands of inexperienced pilots into combat, sometimes on deliberate suicide missions, which would have warped the legitimacy of the performance data. This is important when comparing axis aircraft to those of the allies, who would not present the same statistical anomalies bought about by the frantic collapse of a regime.

So, in 1941, during the first year of the pacific war, the Zero was relatively unchallenged, achieving a kill ratio of 12:1. This set it apart from any American aircraft widely in use. However, by the end of the war, this ratio had dropped far lower, and is hard to confirm. Japanese ace Saburo Sakai pinned the loss of the Zeros superiority to the incredible strength of American aircraft, which he noted could take several hundred machine gun rounds and still fly. Sakai recalls that kill statistics were perhaps most effected by this strength difference, remembering how many Allied aircraft would technically lose dogfights, but would still retreat riddled with bullets. Sakai says that the same was not true for the Zero; just a few hits and the aircraft would go up in flames.

In contrast to this early kill ratio of 12:1 in the Zero, the actual kill ratio of the 109 remains the subject of much dispute. What is known is that Finnish 109 G models held a 25:1 kill ratio against the Soviets. It is also reported that it held a 1.47:1 victory ratio over RAF aircraft; 1.22:1 over the Spitfire, and 1.78:1 over the hurricane, although this is only based off of victories in which the victims aircraft type was specified, which did not always happen.

– Early on – during the Battle of Britain – one other element also played into the high victory count of the 1-owe-9; which was tactics. During these early months of the war, British tactics such as flying in three man ‘vic’ formations, and engaging in Fighter Area Attacks, proved problematic. The German method of flying in dispersed pairs or in finger four, whilst engaging in vertical climbs were tactical advantages that could deny early spitfires from gaining the upper hand.

 

PERFORMANCE

ENGINE

When it came to the power plant of both aircraft, the Bf 109 consistenly came out on top. The majority were fitted with varying types of Daimler Benz DB601s and later DB605s; powerful liquid cooled V12 engines, complete with superchargers. The DB605 often produced 1300 horsepower, and coud be built and tuned to produce far more. Late war 109 K4s could output 2000 horsepower. It could be pushed to War Emergency Power without risk of blowing up the engine – as was the case with practically every other aircraft of the time – thanks to an automated injection system, which would inject a water-methanol mixture at the upper ranges of throttle.

In contrast, the Zero used a 14 cylinder radial engine; the Nakajima Sakae. This initially produced 940 horsepower, although later models could produce 1130 horsepower. A modest amount in comparison to its competition, these engines were still decent, preserving fuel allowing for the Zeros long range, while not necessarily being underpowered.  However, as the war progressed, the availability of high octane fuel needed to keep the engine in optimal performance ranges was low. Instead, the Japanese had to turn to either 85 octane fuel – far too impure for good performance – or to create makeshift solutions, such as extracting elements from palm trees which could be mixed with fuel to increase volatility.

It is obvious that even thought the Zeros engine was not necessarily bad, it simply couldn’t compete with the DB605 in the 109.

SPEED

Speed is where we see a considerable difference.
The A6M5 was capable of reaching 350mph, which it achieved at 15000 feet.
The Bf 109 K4 was clocked at achieving 452mph at 20000 feet.
At sea level, the A6M2 peaked at 270mph, whilst the 109 K4 could reach almost 380mph.
While the Bf 109 would see major improvements in terms of speed as the war progressed, the Zero would remain relatively the same. With the exception of a slight performance boost with the final widespread model – the A6M5 – characteristics were largely the same. It is still unknown exactly why this was the case.

 

ALTITUDE

In terms of service ceiling, the Zero was capable of reaching up to 33000 feet. In contrast, the Bf 109 could operate up to 39000 feet, with some experimental models flying higher thanks to modified forced induction methods.

At the start of the pacific war, American P-40s were notorious for operating poorly above 16000 feet. As such, Zeros were able to win fights by climbing above this altitude and attacking from above, giving both a manoeuvrability and speed advantage. However, the Zero did not have optimal high altitude performance, and newer US aircraft would highlight this.

This is an obvious win for the Messerschmitt. Limited to 33000 feet, and lacking a high performance method of forced induction and cockpit pressurisation, the Zero was clearly not designed for high altitude missions. This was inexcusable later in the war, as B-29 flights with P-51 escorts could sometimes cruise above this 33000 service ceiling. Thus, other Japanese aircraft had to take over in this role. The Luftwaffe would also design aircraft for high altitude fighting, but even then, Bf 109s could still operate at these altitudes, and would regularly be sent up alongside newer aircraft to intercept bombers and fighters.

CLIMB RATE

The climb rate of both aircraft was good. The A6M2 could climb from sea level at 3100 feet/minute. This was comparable, and in some cases better, than most US aircraft at the time.
The Bf 109 would outperform this by a huge margin; late war G-6 variants had a 3900 feet/minute climb rate – better than the P-51D it was competing with, while some G-2 variants were clocked at 4700 feet/minute. Most impressive was the K-4, which could climb at 4850 feet/minute, and in particularly conditions was measured at exceeding 5000 feet/minute. This puts it above the Mark 9 and Mark 14 Spitfires of the late war running on 150 octane fuel, and puts it on an equal footing with Americas state of the art prototype fighter, the P-51H.

The US noted that the Zero had a tradeoff when it came to climbing; it could pull into a climb faster than aircraft such as the F4F Hellcat, but once in consistent climb, the rate would remain similar to that of US aircraft. The reason was simple; the Zero was light, but its engine was only moderately powerful. This initial burst into the climb was known as ‘zoom climb’, and was measured as a seperate statistic to actual consistent climb rate.
The 109 possessed a similarly fast zoom climb ability, which was employed tactically against aircraft such as the spitfire, which would stall out when trying to sustain such a manoeuvre.

RANGE

The Zero was capable of flying up to 1160 miles just off of internal fuel, and up to 1400 miles with an external tank. At the start of the war, this was almost unparalleled. Its primary competition – the F4F Wildcat – could realistically reach 1000 miles only when fully fuelled and equipped with external tanks.  The Bf 109 had no such capability. Off internal tanks, it could reach anywhere between 450 and 750 miles, depending on conditions and variant. Various external tanks were developed or modified, which increased this by various amounts, but never to the point of being able to compete with the Zero.

In this regard, the Zero clearly wins. Long range was a critical consideration during the development of the A6M, as the Japanese knew that any war they engaged in would require long stretches of flying between islands, over large unoccupied territories in Asia, and from carriers. The Germans had no such requirement, and this costed them dearly during the Battle of Britain, in which 109s were often forced to return home either midway through a fight, or before the fight had even begun.

TURNING

In terms of pure aerobatic performance, both aircraft differed greatly. The strength of the Zero was low speed fighting, whilst the 109 performed relatively well at various speeds.
However, the roll rate of the Zero was slow, rated at just 56 degrees per second. In contrast, the 109 roll rate was roughy 90 degrees per second.  But when it came to turning, the Zero held the obvious advantage, being unrivalled in this department. The 109 was manoeuvrable, but turn rate was never its primary focus. However, the Zeros aerobatic performance did come at the cost of such things as armament and armour.  Also, as mentioned, speed did cause impediments with the Zero. Thus, while the Zero could perform better in the turn, this was limited to very specific speeds. The 109, in contrast, could keep consistent performance at both low, medium, and high speeds.

Both the 109 and Zero also had low stalling speeds. The 109 E4 was rated at stalling below 75mph, whilst the Zero was known to reach 63mph before stalling.

One final performance factor worth noting is that the Zero could outperform practically any aircraft of the time in one aspect, and that was its ability to pull into a vertical climb at practically any speed, but stay out of a stall. This was noted by US pilots, who witnessed Zeros pulling into the vertical when being pursued, reaching extremely low speeds, and then pulling the aircraft around to reverse the fight. Practically no allied aircraft could do this, as they would either overshoot the Zero they were pursuing, or enter into a stall, thus losing any ability to accurately pull the Zero into the gunsight. The authority of the Zero at lower speeds was unparalleled throughout the war – hence Allied pilots were taught to fly at higher speeds, and avoid getting into slower fights with a Zero.

 

ARMAMENT

In terms of armament, both aircraft are difficult to compare, given the wide variety of weaponry the Luftwaffe attempted to use on the 109.

Generally speaking, the Zero operated with two 20mm cannons, two .303 machine guns, and the space to be loaded with two 60 kilogram bombs. Differing variants included racks for rockets. Early in the war, this was advantageous, as it allowed for both light strike missions and close air support. The adoption of cannons also meant that the Zero was technically better armed then most early US aircraft, which had 50mm machine guns as standard armament. The Zeros .303 machine guns were also somewhat comparable to the German 20mm MG, which could pack a serious punch.
However, one major drawback was the lack of ammunition. Depending on cannon and machine gun type – which varied over time – the Zero would generally carry 60 rounds per cannon, and 500 rounds per machine gun. Later versions could be loaded with up to 200 rounds per cannon, although generally this was the exception. As Saburo Sakai had said, American Hellcats, Wildcats, and other sturdy aircraft could technically lose dogfights, but still escape alive thanks to their strength, thus such a low reserve of cannon ammunition in the Zero only exacerbated this fact.

In contrast, the 109 utilised a massive variety of weapons during the war, but generally was outfitted with two MG 131 machine guns, and cannons – either a 20mm or a 30mm. MG 131s would often hold 300 or more rounds per gun, while the 20mm cannon would hold 200 rounds. If a larger 30mm cannon was equipped, then roughly 65 rounds were carried. Cannon pods could also be fitted – two under the wings – each with 135 rounds or more. Many different ground attack setups were experimented with. Generally, G models could carry a single 250 kilogram bomb, or up to four smaller 50 kilogram bombs – almost double that of the Zero. Various rockets could also be fitted, including small air to air or air to ground rockets, or larger ones, such as the 45 kilogram BR21.
An important difference here is that the use of 30mm cannons on the 109 drastically increased the probability of a kill. A single 30mm shell could destroy an airframe, and in many cases its fragmentation would wound or kill the pilot.

The 109 clearly wins here. Despite its size, its versatility allowed it to be fitted with a large variety of weapons, and to carry more ammunition.

WEAKNESSES

One weakness the Zero had – which did not prove problematic until later in the war – was its use of a carburettor rather than fuel injection. This meant that any inverted flying, or any movement which resulted in less than positive 1G on the airframe would stall the engine. Even if the pilot were to push the nose down slightly – reducing the aircraft to zero G – the air fuel mixture would be affected. This caused major drawbacks by the time the F6F Hellcat arrived, since American pilots were taught to manoeuvre into the dive if chased by a Zero.
In contrast, the 109 suffered no such issues, as constant improvements effectively overcame such challenges, both in terms of engine performance during manoeuvres, at high altitudes, and in the dive.

The Zero was also recorded as being vulnerable in high speed dives. Firstly, because its carburettor would cause the engine to briefly cut out, and secondly because the control surfaces of the Zero were known to lock up completely above 350mph. In one case, a both wings of a Zero broke off as it reached speed.

The Zero was also a fragile aircraft. Even the lightest damage could bring it down. This was noted by US pilots, who regularly saw Zeros go up in flames or simply crash, due to a lack of self sealing fuel tanks and little pilot armour. Japanese pilots were also well aware of this.

For the 109, one of its consistent weaknesses was range. It was a very small aircraft in contrast to most allied designs, but its engine was still large. While aircraft like the P-51D could fly up to 1200 miles off of internal fuel alone, the 109 would often only reach half that. Modifications could be made to extend that range – either larger internal tanks or external tanks – but this would reduce agility, and at altitudes above 35000 feet, reduced aerodynamic efficiency would cause the aircraft to float and drift all over the place; easy targets for Mustangs.

A second disadvantage – as noted by German pilots – was the 109s canopy. Till the end of the war, the 109 consistently utilised the framed square canopy. There was rear visibility, but it was not as good as the Spitfire or P-51D. There were several supposed reasons for this continued use of this design over a bubble canopy, although it is known that a radial engine 109 was built which featured such a high visibility cockpit.

Some final considerations for this comparison. Firstly, the claim that the Zero would have turned the tide of the Battle of Britain is still unclear. Obviously it could fly far further, but could it have outperformed the manoeuvrable spitfire? This would require its own comparison. Secondly, early war kill statistics with the Zero may have come down to pilot training more than aircraft statistical advantages. Early on, Japanese pilots received far more intense training then the Americans. 109s pilots also had such an advantage, having been taught superior tactics to the RAF early on.

 

CONCLUSION

Summarising, both the 109 and Zero were exceptionally good for their time, but as the war dragged on, both aircraft were forced to adapt. For the 109, this was within reach, whilst for the Zero, such upgrades may not have been possible at all.

The Zero and the 109 were clearly designed for different methods of fighting. The Zero was made to operate over the ocean, at long distances, and fight at medium to low speeds. The 109 was made to fill a variety of roles, and was almost exclusively operating over shorter distances.

By the latter half of the war, the Americans had developed effective tactics of defeating the Zero most of the time; fly high, dive down, fire, and get out. Avoid dogfighting and never fly slow. Thus, the Allies had the Zero figured out, and its lack of a powerful engine meant that it couldn’t compete effectively against these high speed tactics. In contrast, the Bf 109 remained a serious threat from the start of the war until the very end. Models such as the G-10 and K-4 meant that the 109 could always compliment more advanced late war German aircraft.

Over all, the Zero was a great plane, but one which was obviously created for a very specific purpose at a specific point in time. Even with a more powerful engine, the Zeros airframe design limited it from effective high speed fighting, and added weight would have limited its primary strengths; manoeuvrability, fuel efficiency, and low speed fighting. In contrast, the Bf 109 was a truly revolutionary design; small, easy to modify, capable of filling many roles, and most of all, aerodynamically versatile. Perhaps – like many aircraft – it was inferior to the Zero early in world war 2, but its versatile design allowed upgrades to be implemented which not only made it a better fighter than the Zero, but – even by wars end – made it an aircraft capable of competing with anything that was thrown at it.