Previously, we compared America's
two most iconic Pacific War fighters, the F4U Corsair
and the F6F Hellcat. Drawing the conclusion that the Hellcat
with its massive kill count and the Corsair with its statistically
performance advantages, were likely on an equal footing
at the end of the day. But what comparisons can we make about
aircraft operating in the European theater? Two US aircraft are well known for their late war
operations - the P-51 Mustang and the P-47 Thunderbolt. Which of these were better aircraft? Both the Thunderbolt and Mustang differed
greatly in terms of design, but despite their differences
when it came to combat, both would emerge as near equal matches
in many regards. These two aircraft
had very different powerplants. The Mustang, most famously,
used the Rolls-Royce Merlin, a 27 liter V12 engine, whilst
the P-47 used the radial Pratt & Whitney R-2800 The same engine used on the Coursair
and Hellcat in the Pacific. For the sake of argument, let's ignore
the earlier versions of the Mustang, as these versions were powered
by an early model of the Alison V-1710. This V12 engine had poor high
altitude performance and simply could not compete
with Luftwaffe aircraft. The P-51, B and C variants
overcame this with the Merlin engine. This engine was modified
and licensed built by the U.S. as the Packard V-1650, which was fitted
into the P-51D, which arrived in 1944. The final version worth
considering was the P-51H which outperformed
the D model in many areas. However, these aircraft, 2000
of which were ordered in anticipation for a land invasion of Japan,
never saw combat in WWII. So our comparison here
will focus primarily on the performance of both the P-51D
and the P-47D variants. Let's start our comparison with the combat records
of both aircraft. Both entered service in 1942, serving
with the RAAF in various capacities. Generally, both aircraft were used to escort bombers on long range
missions into enemy territory. This was initially the primary role
of the Thunderbolts, but would later be
handed off to the Mustang. As far as kill count is concerned,
the Mustang reigned supreme with somewhere between 4,200 and 4,950 claimed victories
unmatched by any other U.S. aircraft in the European theater. The Thunderbolts, on the other hand, held
between 2,600 and 3,700 claimed victories, significantly lower,
but nevertheless an impressive record. The kill ratios of both aircraft
fall behind that of the nearly 20:1 win loss ratio of the
F6F Hellcat in the Pacific. And it must be said that the kill ratios
of the Thunderbolt and Mustang are heavily disputed. Most claims
pin the Mustang's kill ratio at 10:1 and the Thunderbolts ratio at 4.6:1. Much of this uncertainty comes down
to disputes over air victory claims. The lower ratios of both aircraft
compared to the 11:1 kill ratio of the Corsair and near 20:1
ratio of the Hellcat in the Pacific could be attributed to the higher number
of experienced Luftwaffe pilots. Although this is pure conjecture. As mentioned in the previous Corsair
versus Hellcat comparison, a kill count must be considered
within the operational context. In the Pacific Theater, for example,
the number of experienced Japanese pilots
decreased as the war dragged on. The same was the case for the Germans,
who, despite possessing an overwhelming majority of World
War Two Aces, were short on experienced pilots
after six long years of warfare. While both aircraft
initially served as long range support for bombers
based in England in 1942, over time, the Mustang would become the primary long
range support fighter for such missions, while the Thunderbolt
would focus on other roles. And it is within this rather
complex context that we compare the Thunderbolt and Mustang. Most test results placed the
P-51D climb rate from sea level at around 3,400 feet per minute. Whilst evaluation of the late war
P-51H model saw that number
increased to 5,120 feet per minute. Perhaps the best claim rate of
any American prop aircraft during the war. Surprisingly, evaluations
demonstrated that the earlier P-51B model actually outperformed the D model
with a climb rate of 4,400 feet per minute. Early P-47D variants had a climb rate of 2,300 feet
per minute, while some later D variants achieved climb rates of up to
3,300 feet per minute. These late war P 47Ds demonstrated an increase in climb rate
performance with an increase in altitude peaking at around 10,000 feet. The P-51D in contrast, held
maximum climb rate potential at sea level, which immediately
began to drop off above 4,000 feet. In terms of speed both aircraft were exceptionally fast
within their class, capable of surpassing 400 miles per hour. This was achieved at higher altitudes
and in most cases, higher speeds were necessary
for the aircraft to perform optimally. The P-51B was known to be capable
of reaching 450mph achievable at around 28,000 feet. The P-51D model performed similarly
with a maximum speed of 440mph, which it could achieve
slightly lower at 24,000 feet. The Thunderbolt was almost equally matched. Late-war P-47Ds were clocked
at achieving 445mph, albeit at an even lower altitude of 23,000 feet. The one exception was the later N model
of the Thunderbolt, which was claimed to have been capable of reaching
470mph under the right conditions At sea level the Mustang held the advantage,
but not by much. P-51s were clocked at reaching
almost 380mph, whilst P-47Ds maxed out at around
345mph. If anything, this latter
comparison is more important as the later P-51D held the speed authority closer
to sea level where dogfights were more likely to descend to. At high altitudes,
exceeding 35,000 feet, both aircraft were equally capable
of 400mph. Thus, in terms of speed, it could be said
that both aircraft were equally matched (If we smooth out slight variations
in altitude performances). Both aircraft in this respect
also retained similar service ceilings. The P-47D could operate up to 42,000 feet, whilst the P-51D could operate
at just over 41,000 feet. Again, both aircraft on an equal footing. However, the range of the two aircraft
differed significantly, although both served as long range escorts
for bombing missions over Europe. The Mustang's capability
was practically unmatched. The Thunderbolts could reach near
900 miles at optimal altitude and could be outfitted
with large external drop tanks, increasing its range to somewhere around
1400 miles. There were later tanks
that could extend the range to 1900 miles. In contrast, the P-51D could fly up
to 1200 miles just on internal fuel. However, it was often
fitted with external tanks and could fly just over 1600 miles
when fully fueled. Late war P-47N variants were improved
to match the P-51, in some cases
capable of flying 2000 miles. Maneuverability is another area where we find significant differences
between the aircraft. Whilst the Thunderbolt
certainly wasn't slack in a dogfight, the Mustang would outperform it
by a large margin when it came to roll in turn rates. The P-47 was simply too
heavy to compete in this regard, weighing more than any other single seat
piston aircraft produced by the U.S. at the time. Many pilots who flew the P-47 were later
retrained to fly the P-51, and it was a common testimony to say that
the Mustang was their preferred aircraft. The Mustang's improved
maneuverability and speed, which allowed it to compete with late war
German aircraft such as the BF-109 K4 is what probably won many pilots over. On the other hand,
the smaller number of pilots who preferred the P-47 would cite the Thunderbolt safety
as a significant factor When it came to the safety factor, the Thunderbolt was more robust
than the Mustang. The Thunderbolt was known to be capable
of taking multiple hits without compromising the aircraft. While the Mustang was far more vulnerable. Many say this was due to the Thunderbolt’s
use of an air cooled radial engine. The Mustang relied on liquid cooling, thus any hits to the coolant lines
would result in leaks and soon after, the overheated engine would seize. The Thunderbolt’s airframe was a stronger
overall build and pilots recall the aircraft was better suited
for emergency landings. The lighter Mustang, however, had a higher chance
of breaking apart on ground impact and also flipping over the nose
when the air intake under the fuselage hit ground or water. The Thunderbolt had wider and stronger
landing gear with extreme heavy duty tires, making it easier to land
and safer on makeshift airstrips. Both aircraft were armed with 50
caliber machine guns. This was the standard for the US Air Force
and would remain as such until the Korean War. The P-51D had six such 50
caliber machine guns whilst the P 47D had eight. The Thunderbolt also carried twice
the amount of ammunition 3400 rounds, whilst the Mustang carried 1800. It is hard to gauge
how much of a difference the increased armament of the thunderbolt
made, although it likely helped. Obviously more guns firing simultaneously
increased the possibility of a direct hit. Toward the end of the war many German aircraft were using various
combinations of machine guns and cannons. A single cannon round
could knock out an aircraft, whereas a spray of machine gunfire may
find the target more easily than a cannon. When it came to bombing duties, the
Thunderbolt was the more capable aircraft. Its larger airframe allowed it to carry
two 1,000 pound bombs, one on each wing and a 500 pound bomb under the fuselage, thus allowing for 2500 pounds of explosive. The extra weight did require a long runway for takeoff,
but the solidly built Thunderbolt kept pilots safer from ground fire
could deliver more firepower per sortie, albeit at shorter ranges than the P-51. In the final analysis,
we find both aircraft were very different, demonstrating strengths in differing roles. In the years following WWII, the P-51 (later called the F-51) performed well as a fighter, escort and light
strike aircraft in the early days of the Korean War, but was eventually tasked for close
air support missions. In the close air support role the Mustang struggled
being prone to damage from ground fire. At the time,
pilots believed that the P-47 Thunderbolt would serve this role perfectly, given
its heavy armor and greater firepower. However, their request to fly
the aircraft would be denied and Thunderbolts
would not see the Korean War. One cannot help to think
that the Thunderbolt would have thrived in such a role, leaving the Mustangs
for fighter escort missions. Nevertheless, the Douglas A-1 Sky Raider, a heavy prop aircraft
built at the end of WWII, fulfilled the close air support role
rather well in the Korean War and also later in Vietnam. If we were to draw a final conclusion,
it would not be unreasonable to suggest that during WWII, the P-51
Mustang was the better aircraft overall. Whilst the thunderbolt was safer
and could go further with more, the Mustang was the more agile aircraft
that could get in a fight and kill the enemy at twice
the rate of a Thunderbolt. Killing before being killed
was a supremely motivating priority and given the Luftwaffe’s aerial arsenal,
the Mustang offered exceptional performance
for the task at hand. This is not to dismiss the importance
of the Thunderbolt. It was a remarkable aircraft
serving its role well in WWII, having achieved thousands of victories
and helping secure allied victories throughout Southern
Europe and the Mediterranean.
