If there’s one aircraft that has captivated the public imagination like no other, it’s undoubtedly the North American P-51 Mustang fighter. To many, especially the young pilots who manned it during the concluding stages of combat in Europe, the P-51 stood as the emblem of Allied dominance in the skies over Europe.
Yet, despite the widespread acclaim lavished upon the Mustang, the reality diverges from the romanticized narrative. Initially, the aircraft struggled to find its footing, its prowess as a fighter evolving over time. Curiously, the genesis of the Mustang was accidental, driven more by corporate pride than strategic foresight. Its subsequent evolution followed a similar happenstance trajectory. The U.S. Army had little interest in its inception, and even upon receiving it, the British expressed dissatisfaction with the initial model.
North America manufactures their own fighter.
Prior to America’s involvement in the conflict, the British Purchasing Commission initiated orders for a diverse array of American-manufactured military aircraft. Among these were Curtiss fighters, propelled by Allison engines, designated as the P-40 Tomahawk by the U.S. Army Air Corps. However, Curtiss found itself ill-equipped to fulfill the British demands and proposed a collaborative arrangement with North American Aircraft for licensed production. This proposition, however, did not sit well with James S. “Dutch” Kindelberger, the President of North American, hailing from West Virginia. Instead, he advocated for the development of an entirely new fighter, leveraging the Allison V-1710 engine that powered the P-40, with the aim of creating a more aerodynamically advanced aircraft and harnessing innovative mass production techniques emerging in the American aviation industry.
Upon request, North American promptly embarked on a preliminary design study, astonishingly committing to deliver a prototype within a mere four months. Leveraging data graciously shared by Curtiss from their P-40 design, North American effectively circumvented several months of preliminary design work for the new fighter project. Assurances were made to the British regarding the commencement of deliveries by January 1941, with a projected production rate of 50 aircraft per month until the year’s end. The nomenclature “Mustang” was bestowed upon the aircraft by the British, purportedly drawing inspiration from the untamed equines that roamed the American frontier, though the rationale behind this choice remains elusive. In a bid to expedite production, North American opted for a non-turbocharged variant of the Allison V-1710 engine, albeit at the expense of the aircraft’s performance at higher altitudes.
An Underpowered Engine Ruined the Design
Upon the arrival of the first Mustangs in England, Royal Air Force test pilots swiftly discerned a limitation in their performance. Despite their remarkable agility and speed, these new fighters exhibited a decline in effectiveness beyond altitudes of 15,000 feet due to the loss of power in the Allison engines, which lacked supercharging. Consequently, the RAF opted to allocate the Mustangs to its Army Cooperation Command, a domain hitherto dominated by the nimble Westland Lysander aircraft.
Tasked with tactical reconnaissance, the Mustangs were fitted with cameras, a role they retained throughout the war. Their inaugural operational sortie under the RAF ensign coincided with the ill-fated Dieppe raid in August 1942. Similarly, the U.S. Army Air Corps, following the redirection of 57 Mustangs from British production post-Pearl Harbor, deployed them in a support capacity.
Inspired by the RAF’s utilization of the Mustang within the Cooperation Command, the U.S. Army opted to repurpose the aircraft as a dive-bomber. The prevailing dive-bomber in Army service at the time, the Douglas Dauntless (designated A-24), suffered significant losses in the Southwest Pacific during early 1942 due to its inadequate defensive capabilities. This catalyzed a quest for a more agile and better-armed alternative.
To transform the Mustang into a dive-bomber, enhancements such as dive brakes and bomb-carrying hard points capable of accommodating up to 1,000-pound ordnance were integrated into the base design, resulting in the designation A-36. Deployed to North Africa in the spring of 1943, the 27th and 86th Bombardment Groups (Light) were among the first units equipped with A-36s. Concurrently, RAF Mustangs participated in combat operations in North Africa, although the British predominantly relied on Curtiss Kittyhawks and Hawker Hurricanes for tactical air superiority.
Meanwhile, the 311th Bombardment Group, also outfitted with A-36s, was dispatched to China. Despite the production of over 300 A-36s, the U.S. Army eventually deemed the dive-bomber concept overrated. Consequently, all A-36s were gradually replaced by either fighters or light and medium bombers. While dive-bombing retained its allure in the Navy and Marine Corps, the Army relinquished the practice altogether.
Revamping the P-51 Mustang With the Rolls Royce Merlin Engine
By entrusting the Cooperation Command with its latest Mustang aircraft, the Royal Air Force made a strategic decision to uphold the ongoing development of the renowned Supermarine Spitfire as its primary interceptor. Nevertheless, among RAF test pilots, there lingered a conviction that with the integration of a high-altitude engine, the Mustang could excel in air-to-air combat at the altitudes prevalent in European skies. The turbocharged Rolls Royce Merlin emerged as the prime contender for this enhancement, yet the entirety of Merlin-61 production had been earmarked for Spitfires.
To bolster Merlin production, Rolls Royce entered into a contractual agreement with the Packard automobile company in the United States, commissioning them to manufacture engines under license. Despite Packard’s renown in luxury automobiles, its heritage extended to the design and production of the Liberty engine, pivotal during the Great War and powering U.S.-manufactured aircraft well into the 1920s. The inaugural flight of a British Mustang equipped with a Merlin engine transpired in October 1942. Mere weeks later, a Packard-built Merlin-powered Mustang rolled off the assembly line for the U.S. Army, marking its maiden flight shortly thereafter.
The incorporation of the Merlin engine marked a pivotal transformation for the Mustang. Comparative analyses between Mustangs and Spitfires underscored the North American design’s substantial increase in range, coupled with a notable enhancement in high-altitude performance. This fortuitous amalgamation coincided with the exigencies of the U.S. Army Air Forces’ European operations, which underscored the imperative for a high-performance, long-range fighter aircraft.
Modified for escort missions.
Throughout the years 1942 and 1943, the Mustang fighters remained relatively inactive in the theatre of war, with the exception of the A-36 and RAF Cooperation variants which saw engagement, notably in North Africa. However, unfolding events in Europe paved the way for the Mustang’s evolution into what would later be hailed as the premier Allied fighter of the conflict. By the summer of 1942, the U.S. Eighth Air Force had commenced an escalating strategic bombing campaign against Axis targets across occupied territories, operating from bases in England. In early 1943, this campaign extended into German airspace, where B-17 groups, constituting the backbone of the VIII Bomber Command, faced severe losses from relentless German fighter attacks. The once-assured belief in the invincibility of the Flying Fortresses was shattered as they tangled with Luftwaffe fighters, prompting the suspension of deep-penetration daylight raids into Germany until a suitable long-range escort fighter could be developed.
Throughout 1943, the European theatre relied on RAF Spitfires and USAAF Lockheed P-38 Lightnings and Republic P-47 Thunderbolts for escort duties. Although the P-38 boasted the range to reach Berlin, the P-47s, with their radial engines consuming more fuel, faced limitations, exacerbated by a shortage of available P-38s. The P-38s stationed in England had been redeployed to North Africa early in the year, with replacements only arriving in late summer, leaving Spitfires as the sole escorts until the arrival of operational P-47s in April. It wasn’t until September that P-38s returned to the skies over England, leaving the bombers vulnerable once they surpassed the Spitfires’ range.
Meanwhile, engineers at Wright Field in Dayton, Ohio, sought a swift solution for a mass-producible escort fighter, ultimately turning their focus to the Mustang. The adoption of the Merlin engine had resolved the Mustang’s high-altitude performance issues, while its maneuverability, though constrained by weight and balance considerations, was notable. Enhancing the aircraft’s effective range emerged as the primary challenge, prompting engineers to explore modifications aimed at augmenting the Mustang’s fuel capacity. Additional fuselage tanks were introduced to complement existing droppable external fuel tanks, previously developed for other aircraft types.
Donald Blakeslee: Championing the Use of Mustangs as Escort Fighters
Interestingly, the decision to embrace the Mustang as the principal escort fighter didn’t immediately follow the adoption of the Merlin engine. At first, the Merlin-powered P-51Bs were designated to the tactical air forces forming to bolster ground troops in Europe. The 354th Fighter Group, equipped with the first P-51s, entered combat in Europe in October 1943, joining the freshly organized Ninth Air Force in England. Previously stationed in the Mediterranean, the Ninth shifted its focus to England following the Allied triumph in North Africa, transforming into a tactical air force primed to support Allied ground troops for the impending invasion of Western Europe in mid-1944. With the Ninth slated to accommodate numerous fighter groups, the Eighth Air Force advocated for Ninth fighters to temporarily serve as bomber escorts.
In November 1943, Lieutenant Colonel Donald Blakeslee, deputy commander of the 4th Fighter Group and among the most seasoned American fighter pilots in Europe, was dispatched to fly with the 354th Fighter Group. Blakeslee, a former RAF Eagle Squadron Spitfire pilot who had been flying Thunderbolts, harbored little affection for the P-47 Thunderbolt. Whether he orchestrated the assignment to the 354th or was chosen to evaluate the group’s P-51Bs remains unclear; however, his fervor for the remarkably agile aircraft is evident. The primary advantage of the new P-51 lay in the Merlin engine’s reduced fuel consumption compared to the radial engine P-47, then the principal escort fighter. Although the initial Mustangs in England were equipped only with 184-gallon wing tanks, the Merlin engines’ decreased fuel usage significantly extended their range compared to similarly equipped P-47s. Plans were underway to install an additional 85 gallons in a fuselage tank, while the hard points under the wings allowed for an additional 150 gallons when carrying two 75-gallon drop tanks. Blakeslee was convinced that the Mustang held the key to the long-range escort dilemma, yet all Mustangs were destined for the Ninth Air Force.
In the winter of 1943, Allied military strategists in Europe geared up for the invasion of Western Europe and the subsequent advance toward Germany. Experiences in North Africa and New Guinea had underscored the pivotal role of air power as a “force multiplier,” bolstering ground commanders in their age-old pursuit of territorial conquest.
The Ninth Air Force, a tactical unit tasked primarily with supporting the theater commander, launched a colossal endeavor to bolster its fleet of fighter-bombers, light, and medium bombers to aid ground forces. Once troops were ashore in France, the European theater’s focus shifted from primarily an aerial battle against the Luftwaffe to a ground war aimed at capturing Berlin and defeating Germany. The new Mustangs were viewed as an ideal asset for securing and upholding air superiority over the battlefield and for striking enemy rear areas.
The Mustangs are received by the Eighth Air Force.
At this juncture, the arena of military strategy bore its grim countenance, as Blakeslee and the foremost figures of VIII Fighter Command commenced their intricate dance to wrest control of the Mustangs for the Eighth. They perceived the overarching mission of the Eighth Air Force as strategic bombardment and grasped the pivotal importance of a long-range escort fighter capable of accompanying the bombers deep into German territory, engaging adversaries at high altitudes. With much of Western Europe still under German occupation, aerial assaults on strategic targets retained primacy in the hierarchy of air force objectives.
Their persuasive discourse found fertile ground within the echelons of the Army Air Forces headquarters in England and ultimately prevailed. Measures were set in motion to outfit nearly all squadrons under VIII Fighter Command with the new Mustangs. Meanwhile, P-51s under the purview of IX Fighter Command (alongside other fighters) operated under the operational umbrella of the Eighth Air Force, fulfilling escort duties. Although three P-51 groups were slated for assignment to the Ninth, a compromise led to the allocation of one such group to the Eighth in exchange for the transfer of the recently arrived 358th Fighter Group and its P-47s to the Ninth Air Force. Equipped with Mustangs, VIII Fighter Command assumed control of the 357th and commenced preparations to transition all P-47 and P-38 groups to the new aircraft.
Yet, there existed an outlier—the 56th Fighter Group, the pioneering unit in P-47 deployment, steadfastly adhered to the Thunderbolt until war’s end. Dubbed the Wolfpack for their ferocious tactics akin to hunting German targets like a pack of wolves, the 56th emerged as the highest-scoring American fighter group in the European Theater. Notching a total of 674 aerial victories and 311 ground kills by war’s end, the 56th outstripped all counterparts. Conversely, Blakeslee’s 4th Fighter Group, the inaugural Eighth group to transition to P-51s and boasting the longest combat tenure among American fighter groups in Europe, concluded the war with 583 aerial victories and 469 strafing successes.
While the 4th, having flown Spitfires and P-47s prior to adopting P-51s, laid claim to a marginally higher tally of destroyed aircraft, the P-47-equipped 56th notched nearly 100 more aerial victories. Such findings debunked the oft-touted assertion of the P-51’s superiority. Remarkably, the third-ranking group, exclusively flying Mustangs, was the 357th Fighter Group, the vanguard P-51 unit within VIII Fighter Command. This group boasted 609 aerial victories and 106 ground kills to its credit.
Was Allied air superiority over Europe achieved by the P-51?
Numerous authors have erroneously posited the notion that the advent of the Mustang as an escort fighter marked the turning point in Allied air dominance over the European skies. However, reality diverges from this assertion. The P-51’s advantage lay in its extended range compared to the P-47s, enabling it to penetrate deeper into Germany. Nevertheless, these long-range Mustangs did not make their debut in England until the midpoint of 1944. By then, the efficacy of the Luftwaffe had already begun waning due to various factors, including disruptions in petroleum supplies from Eastern European refineries—largely attributed to Soviet advancements into the oil-rich Balkans—and sustained Allied air campaigns targeting transportation infrastructure such as railways and bridges. Initial U.S. Army Mustang deployments in Europe lacked the additional fuel capacity crucial for deep incursions into German territory.
Another contributing factor to the Luftwaffe’s decline was evident. Throughout 1942 and 1943, German fighter pilots predominantly avoided direct engagement with Allied forces, opting instead to target bombers once their escorts had exhausted their fuel and turned back. By spring 1944, advancements by the VIII Fighter Command had significantly extended the range of P-38s and P-47s through the addition of external fuel tanks, enabling escorts to penetrate deeper into German airspace alongside the bombers. Remarkably, the twin-engine P-38s even reached Berlin. Leveraging their enhanced range, the VIII Fighter Command sanctioned ground-level attacks on Luftwaffe airfields, decimating both airborne and grounded German fighters. Consequently, by the time P-51s became prevalent in Europe, Allied air superiority was firmly established.
However, the transformation of Mustangs into long-range fighters was not devoid of challenges. Incorporating 85-gallon internal fuel tanks posed control issues during combat maneuvers when filled to capacity. To mitigate this, VIII Fighter Command regulated fuel levels to a maximum of 35 gallons upon entering potential combat zones. Additionally, the inclusion of external tanks, although essential for range extension, exacerbated aerodynamic drag and stability concerns, limiting the effective range of Mustangs. Moreover, akin to the early hurdles faced by the twin-engine P-38s, Mustangs encountered heating deficiencies at high altitudes during their initial combat phases.
Contrary to popular belief, the deployment of P-51s did not relegate P-47s solely to the fighter-bomber role, with Mustangs exclusively tasked with escort duties. Instead, VIII Fighter Command adopted a nuanced approach. It allocated more seasoned P-47 groups to patrol regions vulnerable to Luftwaffe assaults on the bomber formations, while the longer-ranging P-38s and P-51s spearheaded assaults deep into enemy territory.
Mustangs in the role of ground attack aircraft.
The Mustangs found themselves pressed into service as fighter-bombers, particularly as the Luftwaffe’s fighter squadrons were effectively grounded due to fuel and oil shortages. Thunderbolts and Lightnings maintained their roles in escort missions until the latter part of 1944, when Mustangs gradually supplanted them across most VIII Fighter Command squadrons. However, this transition occurred relatively late in the conflict as more Mustangs became available. Thunderbolts and Lightnings continued to serve as the primary escort fighters in Europe until mid-1944. Interestingly, as Mustangs began to dominate the skies in large numbers, the focus of the air war shifted downward, with providing close air support for ground troops emerging as the primary mission of the Army Air Forces.
Although the Mustang assumed the role of primary escort fighter within VIII Fighter Command, P-51s were not absent from the tactical air commands of the Ninth Air Force. Under Brigadier General O.P. Weyland’s XIX Tactical Air Command, a group of Mustangs became operational on July 31, 1944, supporting General George S. Patton’s Third Army. Additional Mustang groups were transferred in and out as operational requirements evolved. However, the Mustang encountered a significant limitation when it came to low-altitude attacks. The liquid-cooled Merlin engines rendered the P-51s more susceptible to ground fire compared to the radial-engine P-47s, often necessitating their assignment to provide fighter cover over the battlefield to counter German aircraft.
Thunderbolts boasted two additional machine guns compared to Mustangs, making them better suited for attacking German armor and other ground targets. Nonetheless, P-51s undertook their fair share of ground attack missions, utilizing their six .50-caliber machine guns for strafing, firing rockets, and dropping bombs and napalm. Mustangs from the Eighth Air Force frequently transferred to Ninth Air Force control, particularly during the Allied counteroffensive against the German Ardennes offensive in the winter of 1944-1945.
The Red Tails of the Tuskegee Airmen
In the late spring of 1944, Mustang-equipped squadrons joined the ranks of the Fifteenth Air Force, stationed at Italian bases, marking a pivotal shift in combat strategy. Three squadrons, formerly equipped with P-40s, eagerly welcomed the sleek P-51s into their arsenal. Concurrently, the 52nd Fighter Group, operating under the Twelfth Air Force, bid farewell to their Spitfires, embracing the formidable Mustangs as their new aerial steeds. Another significant addition to the Fifteenth Air Force was the 332nd Fighter Group, stirring controversy as an all-black unit famously linked with the Tuskegee Airmen. Transitioning from P-47s, they proudly adorned their aircraft tails with a striking hue of red, a distinct marker amidst the chaos of battle. Members of the group boasted of their impeccable record, claiming to have safeguarded every bomber under their escort, although the veracity of such assertions remains subject to scrutiny.
Establishing the standard for the P-51
Upon the introduction and endorsement of the Merlin-powered Mustangs, the Army Air Forces commenced strategizing to discontinue the production of other aircraft types in order to streamline maintenance and logistical operations. However, not all commanding officers shared the fervor for the Mustang exhibited by Brig. Gen. William Kepner of the VIII Fighter Command. Upon receiving notification from Headquarters, U.S. Army Air Forces that his command’s P-38s and P-47s were to be replaced by P-51s, Far East Air Forces commander Lt. Gen. George C. Kenney adamantly opposed the decision, stating a firm “No!”
In the early stages of the war, Kenney had expressed indifference to the types of aircraft allocated to his theater when speaking to General Henry H. Arnold. However, as the conflict progressed, he developed a preference for the twin-engine P-38. Kenney oversaw a theater encompassing vast stretches of ocean, where he believed the additional engine of the P-38 offered his pilots a better chance of survival compared to the P-51. Moreover, the P-38s of the Fifth and Thirteenth Air Forces had demonstrated considerable success in engaging Japanese aircraft since their combat debut in late 1942. By mid-1944, Far East Air Forces P-38s were undertaking missions spanning distances of 700 miles, surpassing those encountered in Europe. Consequently, the P-38 remained the favored fighter aircraft within the Far East Air Forces until the war’s conclusion.
Despite General Kenney’s initial resistance to integrating Mustangs into his seasoned fighter squadrons, some newly arrived units were outfitted with the P-51. In early 1945, the 460th Fighter Squadron joined the P-47-equipped 348th Fighter Group, incorporating P-51s, prompting the remainder of the group to transition to the more agile fighter. Notably, the earliest Mustangs deployed in the Southwest Pacific were F-6D reconnaissance aircraft, commencing operations with the 82nd Reconnaissance Squadron in late 1944.
P-51 in the Pacific
A short while following their initiation into combat, Captain William Shomo, leading the squadron, embarked on a reconnaissance flight. Alongside him was Lieutenant Paul Libscomb, his wingman. In the midst of their mission, they stumbled upon a formation of 13 Japanese aircraft, comprising a bomber and 12 fighter escorts. Despite their lack of combat experience, Shomo and Libscomb displayed remarkable prowess, successfully downing the bomber and 10 of its accompanying fighters. Their exceptional bravery earned Shomo the prestigious Medal of Honor, while Libscomb was decorated with the Distinguished Service Cross. Meanwhile, elsewhere in the Southwest Pacific, other Mustangs were in service with the 3rd Air Commando Group.
The Mustang fighters were also deployed by Air Commandos in the China-Burma-India Theater, where they played a pivotal role alongside the Fourteenth Air Force during the war’s concluding phase. Initially supporting British ground operations in Burma, these Air Commando Mustangs transitioned primarily to ground attack missions, targeting Japanese airfields and supply lines. Although not the first Mustangs in the CBI, these agile aircraft made their debut in mid-1943 with the arrival of the 311th Bombardment Group, which boasted two squadrons of A-36s and one squadron of early model Allison-equipped P-51As. Accompanying them was the 8th Photo-Reconnaissance Group, operating the F-6 variant of the aircraft. Subsequently, Mustangs replaced the Curtiss P-40s in the renowned 23rd Fighter Group, the Army Air Corps unit that succeeded the famed Flying Tigers of the American Volunteer Group following the United States’ entry into the war in early 1942.
In the war’s concluding stages, the Army Air Forces commenced deploying P-51s to the Central Pacific to provide escort for Boeing B-29 Superfortresses conducting long-range bombing raids over the Japanese home islands from bases in the Marianas. To establish a forward operating base for the P-51s, U.S. Marines executed a landing on Iwo Jima, an island situated 660 miles southeast of the Japanese mainland. The inaugural mission over Japan occurred on April 29, 1945, with 108 P-51s escorting B-29s. Additionally, Mustangs were stationed on Okinawa, from where they joined other American fighters and ground attack aircraft in conducting raids over Japan.
The P-51 Mustang, Ever-Evolving
Being the inaugural patron of the Mustang, the British Royal Air Force sustained the utilization of this aircraft type across a myriad of roles throughout the duration of the war. Following its initial deployment for reconnaissance purposes, RAF Mustangs undertook duties as escort fighters and ground attack aircraft not only in the European and Mediterranean theaters but also in Asia. Moreover, Mustangs found service with other air forces such as the Royal Australian Air Force, the Royal Canadian Air Force, the Netherlands East Indies Air Force, and the South African Air Force, albeit the latter was operational solely in the concluding weeks of the conflict.
Interestingly, the characteristic that bestowed the Lockheed P-38 with preeminence as a fighter in the Southwest Pacific spurred North American to conceive the notion of crafting a twin-engine iteration of the Mustang. North American pursued this concept with fervor, augmenting its design by incorporating a second pilot. The resultant Twin Mustang, officially designated by the U.S. Army as the F-82, entailed the fusion of two P-51 fuselages conjoined by a compact wing and a solitary stabilizer bridging the two. Although production commenced in early 1945, merely 20 units were completed by the cessation of hostilities.
