The Effects of the P-51 Mustang In World War II


This paper deals with the contributions of the P-51 Mustang
to the eventual victory of the Allies in Europe during
World War II. It describes the war scene in Europe before
the P-51 was introduced, traces the development of the
fighter, its advantages, and the abilities it was able to
contribute to the Allies' arsenal. It concludes with the
effect that the P-51 had on German air superiority, and how
it led the destruction of the Luftwaffe. The thesis is
that: it was not until the advent of the North American
P-51 Mustang fighter, and all of the improvements,
benefits, and side effects that it brought with it, that
the Allies were able to achieve air superiority over the
Germans. This paper was inspired largely by my grandfather,
who flew the P-51 out of Leiston, England, during WW II and
contributed to the eventual Allied success that is traced
in this paper. He flew over seventy missions between
February and August 1944, and scored three kills against
German fighters.
Table of Contents Introduction Reasons for the Pre-P-51 Air
Situation The Pre-P-51 Situation The Allied Purpose in the
Air War The Battle at Schweinfurt The Development of the
P-51 The Installation of the Merlin Engines Features,
Advantages, and Benefits of the P-51 The P-51's Battle
Performance The Change in Policy on Escort Fighter Function
P-51's Disrupt Luftwaffe Fighter Tactics P-51's Give
Bombers Better Support Conclusion Works Cited
Introduction On September 1, 1939, the German military
forces invaded Poland to begin World War II. This invasion
was very successful because of its use of a new military
strategic theory -- blitzkrieg. Blitzkrieg, literally
"lightning war," involved the fast and deadly coordination
of two distinct forces, the Wermacht and the Luftwaffe. The
Wermacht advanced on the ground, while the Luftwaffe
destroyed the enemy air force, attacked enemy ground
forces, and disrupted enemy communication and
transportation systems. This setup was responsible for the
successful invasions of Poland, Norway, Western Europe, the
Balkans and the initial success of the Russian invasion.
For many years after the first of September, the air war in
Europe was dominated by the Luftwaffe. No other nation
involved in the war had the experience, technology, or
numbers to challenge the Luftwaffe's superiority. It was
not until the United States joined the war effort that any
great harm was done to Germany and even then, German air
superiority remained unscathed. It was not until the advent
of the North American P-51 Mustang fighter, and all of the
improvements, benefits, and side effects that it brought
with it, that the Allies were able to achieve air
superiority over the Germans.
Reasons for the Pre-P-51 Air Situation The continued
domination of the European skies by the Luftwaffe was
caused by two factors, the first of which was the
difference in military theory between the Luftwaffe and the
Royal Air Force. The theories concerning the purpose and
function of the Luftwaffe and RAF were exactly opposite and
were a result of their experiences in World War I. During
WW I, Germany attempted a strategic bombing effort directed
against England using Gothas (biplane bombers) and
Zeppelins (slow-moving hot-air balloons) which did not give
much of a result. This, plus the fact that German military
theory at the beginning of WW II was based much more on
fast quick results (Blitzkrieg), meant that Germany decided
not to develop a strategic air force. The Luftwaffe had
experienced great success when they used tactical
ground-attack aircraft in Spain (i.e. at Guernica), and so
they figured that their air force should mainly consist of
this kind of planes. So Germany made the Luftwaffe a ground
support force that was essentially an extension of the army
and functioned as a long- range, aerial artillery. The RAF,
on the other hand, had experimented with ground-attack
fighters during WW I, and had suffered grievous casualty
rates. This, combined with the fact that the British had
been deeply enraged and offended by the German Gotha and
Zeppelin attacks on their home soil, made them determined
to develop a strategic air force that would be capable of
bombing German soil in the next war. Thus, at the beginning
of WW II, the RAF was mostly a strategic force that
consisted of heavy bombers and backup fighters, and lacked
any tactical dive- bombers or ground-attack fighters.
(Boyne 21)
The Pre-P-51 Situation Because of these fundamental
differences, the situation that resulted after the air war
began was: bombers in enemy territory vs. attack planes.
The "in enemy territory" was the second reason for the
domination of the Luftwaffe. At the beginning of WW II, and
for many years afterward, the Allies had no long-range
escort fighters, which meant that the bombers were forced
to fly most of their long journeys alone. (Perret 104)
Before the P-51 was brought into combat, the main Allied
fighters were the American P-47 Thunderbolt and the British
Spitfire, neither of which had a very long range. The
rule-of-thumb for fighter ranges was that they could go as
far as Aachen, which was about 250 miles from the Allied
fighters' home bases in England, before they had to turn
around. Unfortunately, most of the bombers' targets were
between 400 and 700 miles from England. (Bailey 2-3) This
meant that bombers could only be escorted into the Benelux
countries, northern France, and the very western fringe of
Germany. When these unescorted, ungainly, slow,
unmaneuverable bombers flew over Germany, they were
practically sitting ducks for the fast German fighters. On
the other hand, the bombers were equipped with several
machine guns and were able to consistently shoot down some
of their attackers. Because of this, "U.S. strategists were
not yet convinced of the need for long-range fighters; they
continued to cling to the belief that their big bomber
formations could defend themselves over Germany." (Bailey
The Allied Purpose in the Air War The Allies knew that they
had to drive German industry into the ground in order to
win the war. Since the factories, refineries,
assembly-lines, and other industry-related structures were
all inland, the only way to destroy them was by sending in
bombers. The only way that the bombers could achieve real
success was by gaining air superiority, which meant that
nearly all of the bombers would be able to drop their bombs
without being harassed by fighters, and return home to
fight another day. The problem with this sequence was that
the Allies did not have this superiority, (Bailey 28)
because their bombers were consistently getting shot down
in fairly large numbers, by the German fighters that kept
coming. The Allies soon realized that in order to gain this
superiority, they would have to destroy more German
fighters. In order to destroy the fighters, they would have
to be forced into the air in greater numbers. In order to
get more German fighters into the air, the more sensitive
German industries would have to be attacked with more
aggression. Following this logic, the Allies began a
intensified bombing effort that resulted in the famous
bombings of Hamburg (July 24-28, 1943) and Ploesti (August
1, 1943), among others. And, indeed, this did cause more
fighters to come up to meet and engage the bombers.
Unfortunately, the bombers were overwhelmed by the German
opposition, and their losses soon began to increase. (Copp
359) The Allied air forces had, in effect, pushed a stick
into a hornets' nest, hoping to kill the hornets when they
came out, and been stung by the ferocity of their response.
The Battle at Schweinfurt The culminating point of this
backfiring plan was the second bombing raid on Schweinfurt,
which occurred on October 14, 1943. Schweinfurt was the
location of huge ball-bearing factories that supplied most
of the ball-bearings for the entire German military. The
U.S. Eighth Air Force had staged a fairly successful raid
on the same city two months earlier, but the second time
around, the Germans were ready for them. The official
report afterwards said that the Luftwaffe "turned in a
performance unprecedented in its magnitude, in the
cleverness with which it was planned, and in the severity
with which it was executed." Of the 229 bombers that
actually made it all the way to Schweinfurt, 60 were shot
down, and 17 more made it home, but were damaged beyond
repair. This was a 26.5% battle loss rate for the
Americans, while the Germans only lost 38 airplanes the
whole day, from all causes. (Boyne 327) This battle was one
of the key battles of the war, and undeniably proved to the
Allies that the bomber offensive could not continue without
a long-range fighter escort. (Copp 444) Even before October
of '43, some had begun to realize the need for this kind of
fighter. In June, the Commanding General of the Army Air
Forces, General Hap Arnold, wrote a memo to his Chief of
Staff, Major General Barney Giles, which said:
This brings to my mind the absolute necessity for building a
fighter airplane that can go in and out with the bombers.
Moreover, this fighter has got to go into Germany. . . .
you use an existing type or have to start from scratch is
problem. Get to work on this right away because by January
'44, I
want a fighter escort for all our bombers from the U.K. into
Germany. (Copp 413-414)
The Development of the P-51 In April of 1940, "Dutch"
Kindleberger, president of North American Aviation, visited
Sir Henry Self, the head of the aircraft division of the
British Purchasing Commission, asking if Britain would like
to buy some of his B-25 bombers. Self was not interested in
buying any more bombers, but was interested in buying a
good fighter. He directed Kindleberger to the Curtiss
company, who had a new fighter design, but were too busy
building P-40's to do anything with it. Kindleberger went
to Curtiss and bought their design for $56,000. He promised
Self to have the planes ready by September of 1941. The
prototype of the NA-73, as it was called, was ready to fly
in October of 1940 and proved to have an excellent design.
The NA-73 had a revolutionary wing design that allowed it
to fly at high speeds without adverse compression effects.
In other planes, as they approached a certain speed,
usually around 450 mph, the air would be flowing around the
wing at nearly the speed of sound, putting huge amounts of
pressure on the wings, which were unable to deal with the
stress. The NA-73 did not have this problem, which meant it
could fly safely at much higher speeds. Another
revolutionary idea in the plane was the way heated air from
the radiator was dealt with. The NA-73's engineers designed
it to expel this air and boost the planes speed by 15 or 25
mph. The engineers also worked especially hard on making
the plane as aerodynamic as possible, and so they
positioned the radiator in a new place, made the fuselage
as narrow as possible, and set the cockpit low in the
fuselage. (Perret 118-119) It was at this point that an
error was made that made the Mustang useless as a
long-range offensive fighter. When the NA-73 was mass
produced as the P-51, it was powered by a 1550 horsepower
air-cooled Allison engine, which did not have a
supercharger and lost performance above 11,800 ft. At high
altitudes air pressure goes down, and so there is less
oxygen in a given amount of air, which means that engines
do not burn as cleanly, and so lose power. Superchargers
compress air before it is pumped into the engine cylinders
so that there is enough oxygen for the engine to function
well. The early Allison-engined planes did not have the
supercharger, and so were limited to low-altitude
operations. Even without a high- altitude capability, the
Mustang was an impressive plane and was bought in quantity
by the RAF. It flew its first mission on May 10, 1942,
against Berck-sur-Mer on the French coast. (Grant 17-18)
The Installation of the Merlin Engines So, for the next
eighteen months, the P-51A's continued to fly with the RAF,
doing their unexceptional jobs well. After the plane began
to go into combat, some people began looking into the idea
of fitting the Mustang with a more powerful engine. As the
RAF said, it was "a bloody good airplane, only it needs a
bit more poke." (Grant 22) One day, an RAF test pilot was
flying a P-51A and the thought occurred to him that the
plane could be fitted with a Rolls-Royce Merlin engine,
which had about 300 more horsepower and included a
supercharger. He suggested it to Rolls-Royce's Chief
Aerodynamic Engineer and "both men realized that the
combination of this sort of performance with the
aerodynamically efficient airframe of the Mustang would
revolutionize its potential." (Grant 22) This plan was duly
carried out and in November 1943, the first group of
P-51B's arrived in England.
Features, Advantages, and Benefits of the P-51 This final
Mustang design was superior to anything else that flew at
the time. The P-51B had a huge internal gasoline tank
capacity (around 425 gallons) and its engine was very
economical, using about half the gasoline of other American
fighters. This meant its range was 1080 miles and could be
extended to 2600 miles when extra drop-tanks were attached
to the wings. This made its range far more than any Allied
or German fighter's. As far as performance went, it was
superior to all others as well. Neither of the other two
main American fighters could compete; the P-47 was too
heavy and the P-38 had too many technical problems. The
British fighters, the Spitfire and the Hurricane did not
have the range, speed, or power. But most important was its
superiority over the German fighters, the most important of
which were the FW-190 and the Me-109. The Mustang was 50
mph faster than the Germans up to 28,000 ft beyond which it
was much faster than the FW-190 and still substantially
faster than the Me-109. The Mustang had between 3000 and
4000 lbs more weight, and so was able to outdive either
German plane. The tightness of its turns was much better
than the Me-109 and slightly better than the FW-190. (Grant
31, Boyne 389-390, Bailey 153) The result of all of this
was that the Allies now had a plane that could go with the
bombers all the way to and from their targets, fight and
defeat the bombers' German attackers, and not run out of
The P-51's Battle Performance So, at the end of 1943 and
the beginning of 1944, the new American P-51B's began
arriving in England in force. (Dupuy 34) For the first few
months of the year, the Mustangs were settling in and
having their systems perfected. But by March, the Mustangs
had decisively taken control. The arrival and subsequent
heavy use of the P-51's had several effects. The first
effect that the Mustangs had was in the running air battles
over Europe. Before the beginning of 1944, the bombers had
been alone as they approached their faraway targets. But
the P-51 changed this, and quickly made an impression on
all concerned, enemy and ally alike. For example, on
January 11, 1944, the Eighth Air Force launched its first
deep penetration of Germany with P-51 coverage. The
bombers' targets were the cities of Oschersleben and
Halberstadt, where many German planes were being
constructed. When they arrived, there were 49 Mustangs
covering a force of around 220 bombers. Even though the
bombers suffered heavy casualties, they were able to
inflict substantial damage on their target factories. But
the most significant thing about the battle was the shining
performance of the P-51's. Since the bombers were attacking
two different cities, the Mustang force had to divide into
two groups, to support the different attacks. Because of
the sensitive nature of the bombers' targets, the Luftwaffe
came out in force to defend their factories. During the
ensuing melee, the 49 P-51's shot down 15 enemy planes
without suffering a single loss. Major Howard, the group's
leader, was credited with four kills within minutes.
(Bailey 155) In the grand scheme of things, this battle was
insignificant, but it goes to show how much of advantage
the P-51's had over their German counterparts. Considering
that these were essentially first-time pilots in the
Mustangs' first big battle, this is very impressive.
The Change in Policy on Escort Fighter Function Another
thing happened at the same time as the arrival of the P-51
that greatly aided the Allies and fully utilized the great
capabilities of the Mustang. Before the beginning of 1944,
the bomber escort's primary function was to fly alongside
the bombers, repel any attacks made on the bombers, and
generally make sure the bombers stayed safe. Indeed, the
motto of the Eighth Air Force Fighter Command was "Our
Mission is to Bring the Bombers Back Alive." One day at the
beginning of the year, Jimmy Doolittle, who was the
commander of the Eighth Air Force, saw a plaque on the wall
with this motto on it and said, "That's not so. Your
mission is to destroy the German Air Force. . .Take that
damned thing down." (Copp 456) And just days before, in his
New Year's Day address to the Eighth Air Force command,
General Arnold had said, "My personal message to you-this
is a MUST- is to destroy the enemy air force wherever you
find them, in the air, on the ground and in the factories."
(Copp 456) What this meant was that the escort fighters
were not tied to the bombers anymore, and were free to roam
over the countryside and through the towns and cities,
destroying at will. The sweeping Mustangs were released to
ravage German convoys, trains, antiaircraft gun
emplacements, warehouses, airfields, factories, radar
installations, and other important things that would be
impractical to be attacked by bombers. The fighters were
also able to attack German fighters when they were least
prepared for it, like when they were taking off or forming
up in the air. What made this possible was the increase in
the number of American planes present in Europe. This
increase in the number of Allied planes compared to the
number of German planes continued to the point that, on
D-Day, the Allies used 12,873 aircraft while the Germans
were only able to muster a mere 300. (Overy 77) By using
this overwhelming numerical advantage, the Allied fighters
were able to swamp their opponents in an unstoppable flood
of planes.
P-51's Disrupt Luftwaffe Fighter Tactics This increase in
the number of fighters plus the change in fighter
philosophy allowed the escorts to cover the bombers while
simultaneously ranging far from the bomber stream and
destroying all that they could find. This caused the
disruption of several effective German fighter tactics that
had been used successfully in the past. One of these
tactics was the deployment of slow, ungainly German planes
that would fly around the bomber formations, out of gun
range, and report back on where the bombers were and where
their weak spots were. The free-ranging P-51's soon wiped
out these planes. Another popular tactic was to mount
rocket launchers on the wings of some of these slower
craft, have them linger just out of range of the bombers'
guns, and send rockets flying into the bomber formations.
These rocket attacks were terrifying to the bomber crews,
and often broke up formations, sending some planes to the
ground. Obviously, these attacks also came to a halt. Most
importantly, the fast German fighters had to change their
attack tactics. Beforehand, they would fly alongside the
formations and wait for the right moment to swoop in and
attack a bomber. Now, they were forced to group together
several miles away from the bombers, and then turn and made
a mad rush at the bombers, hoping to inflict sufficient
damage on one pass to shoot down some number of enemy
bombers. They could not afford to stay with the bombers for
very long for fear of being attacked by the Mustangs.
(Perret 293) Indeed, soon after the P-51's entered onto the
scene, Hermann Goering, the commander of the Luftwaffe,
recommended that the German defensive fighters avoid combat
with the P-51, and only attack bomber formations when there
were no fighters around. The result of all of this is that
the American fighters, led by the P-51's, soon began to
gain air superiority. Not long after Goering's
recommendation, a sarcastic Luftwaffe officer commented
that the safest flying in the world was to be an American
fighter over Germany. (Dupuy 35-36) It is obvious that the
P-51, once it was supplied to the Eighth Air Force in great
quantities, and unleashed by Doolittle and Arnold's new
fighter policies, soon took a heavy toll on German air
P-51's Give Bombers Better Support Another profound effect
that the increased fighter coverage had was on the most
important people, the bombers. After the entrance of the
P-51, and the virtual elimination of the German fighter
threat, the bombers were in much less danger from German
fighters. The result of the decreased danger to the bombers
is subtle, but obvious when thought about. Imagine a bomber
crew sitting in their cramped plane, unable to move around
or evade attack during their bombing run while numerous
German fighters speed past their plane firing at them.
Second lieutenant William Brick, the bombardier of a B-17
bomber, tells about the day he flew to Linz, Austria on a
bombing run:
. . . The remainder of the run must be perfectly straight
level, without the slightest deviation, or our five-
thousand-pound bomb load will fall wide of the target. No
action is possible. . . Then comes the sickening rattle of
machine-gun bullets and cannon fire hitting our ship;
the flak from the antiaircraft batteries, German fighter
zoom in so close that it seems they will ram us. . . Even
at the
sub-zero temperatures of this altitude, salty sweat pours
down my
face and burns my eyeballs. Cursing and praying, I am
gripped by
the same brand of helpless fear that fliers experience
every bomb run. I feel the terror in my hands, in my
even in my feet. Long after returning from the mission, its
effects will remain etched indelibly on my face. . . .
(Brick 61) This kind of terror experienced by the entire
crew of the bombers was sure to affect their concentration
and their carefulness. Indeed, "it is an undeniable, if
unquantifiable, fact that it is easier to bomb precisely
when you know you will probably not be shot out of the
sky." (Boyne 341)
Conclusion In the end, the way that the Allied air forces
gained air superiority was by destroying its opposition.
The ways in which the fighters were able to destroy German
fighters were diverse. The fighters utilized their high
speed and maneuverability to fly low-level strafing
missions that ranged over large expanses of territory and
destroyed many Luftwaffe craft on the ground. This tactic
was responsible for the destruction of many dozens of
fighters that were unable to go on and fight in the air.
Another way that the Allied fighters destroyed their
opposition, and the most important way, was by luring them
into the air. Going back to the hornets' nest analogy, the
Allies stopped pushing the stick and decided to bide their
time until the moment was right. When they did start
pushing the stick into the nest again, they were armed with
a metaphoric insecticide. In real life, this "insecticide"
was the P-51. Beforehand, the Allies had nothing that could
stop the "hornets" and so were helpless to stop their
attack. But after they had developed an "insecticide"
capable of killing the "hornets," they proceeded to lure
the hornets into the open where they could be destroyed. In
real life, the bombers were the lure that brought the
Luftwaffe into the air. Using the long-range Mustangs, the
Allies were able to make their bombing raids more effective
and more deadly to Germany. The approaching end of the
Third Reich was enough to get the German fighters into the
air to try to stop the bombers from wrecking their war
effort. "Air superiority had been won not by bombing the
enemy's factories into oblivion; instead, it was won by the
long-range fighter, using the bomber formations as bait to
entice the Luftwaffe to fight." (Boyne 338) With the advent
of great numbers of the highly superior P-51 Mustang, the
German fighters that came up to attack the bombers quickly
met their match and were easily repelled by the Mustangs.
Works Cited
Bailey, Ronald H. The Air War in Europe. Alexandria,
Virginia: Time-Life
Books, 1979. A simple, straight-forward book that includes
on the development of military aviation, and includes many
pictures that
chronicle the air war.
Boyne, Walter J. Clash of Wings: World War II in the Air.
New York:
Simon &
Schuster, 1994. A very informative and user- friendly book
that dealt
the air aspect of all fronts and theaters of WWII. It
includes much data
numerous planes in its appendices.
Brick, William. "Bombardier." American History, April 1995,
pp. 60-65. A
short magazine article following the story of how a U.S.
airman was shot
down over Austria, and his subsequent imprisonment by the
Copp, DeWitt S. Forged in Fire: Strategy and Decisions in
the Airwar
Europe, 1940-1945. Garden City, New York: Doubleday &
Company, 1982. A
dealing mostly with the U.S. involvement in the War, with
emphasis on the politics of the military officials, and how
the major
strategic decisions were made.
Dupuy, Trevor Nevitt. The Air War in the West: June 1941 to
April 1945.
York: Franklin Watts, Inc., 1963. A short, very basic book
that did not
into depth, but did cover its material well.
Grant, William Newby. P-51 Mustang. London: Bison Books
Limited, 1980. A
relatively short book, but one that dealt solely with the
P-51, and went
into considerable depth concerning its construction and use
during WWII
in later conflicts.
Overy, R.J. The Air War: 1939-1945. New York: Stein and Day
1980. A fairly dry book that dealt mostly with the
economics and
generalities of the air war, without dealing too much with
the actual
Perret, Geoffrey. Winged Victory: The Army Air Forces in
World War II.
York: Random House, 1993. A good book that covered its
topic well,
in-depth discussion of the contributions of the other
allies' forces is
dealt with.

Quotes: Search by Author