Arrogant U.S. Generals Made the P-51 Mustang a Necessity
With better leadership, the iconic fighter plane might’ve been unnecessary
by JAMES PERRY STEVENSON and PIERRE SPREY
The benefits the P-51 Mustang brought to aerial battles in World War II, particularly over Germany, are reasonably well known. The iconic fighter plane could fly higher, faster, farther and generate more kills per sortie than the U.S. Army Air Force’s aviation bureaucracy’s preferred P-47s or P-38s.
However, the real P-51 Mustang story is just as much about the difficult gestation of a great new fighter as it is about the quashing of the drop tanks urgently needed to extend the range of existing fighters. Then there’s the guerilla tactics some officials unleashed in the corridors of power to overcome the Army’s “not invented here” hostility to the plane, as well as the mendacious post-war rewriting of history by the newly minted U.S. Air Force.
Between World War I and World War II, bombers began flying higher and faster than existing obsolete biplane fighters. Still, the U.S. Army Air Corps’ bomber generals refused to foresee that enemy fighters might prevent the lumbering aircraft from always getting through to the target.
These officers even ran field exercises designed to support their premises of bomber invincibility. U.S. Army Lt. Col. Henry “Hap” Arnold, a leading bomber advocate who would eventually become chief of the service’s Air Corps, was particularly determined to prove this point.
“Exercises held in 1931 seem to reinforce the idea that fast bombers could fare well on their own,” military historian Dr. Tami Davis Biddle wrote in Rhetoric and Reality in Air Warfare. “Arnold reached this conclusion, as did the umpires, one of whom proclaimed: ‘[I]t is impossible for fighters to intercept bombers and therefore it is inconsistent with the employment of air force to develop fighters.’”
This rigid mindset became embedded in the Army’s air power strategy, its budget battles and its endless barrages of air power propaganda.
Within just a few years, however, fighter war games and actual air combat abroad provided ample evidence the Army Air Corps brass was committed to the wrong conclusion.
“[I]n 1933, … squadrons intercepted 55 percent of enemy day-formations as they flew toward the target, … another 26 percent as they left it; [and] 67 percent of individual night raiders were intercepted,” Biddle noted. “But what might have seemed clear defensive victories were not perceived as such: proponents of strategic bombing refused to grasp the devastating bomber attrition forecast by these exercise outcomes.”
“When assessing results, the bomber advocates created both formal rules and cognitive filters [to insure] they would see what they expected to see: the primacy of the aerial offensive waged by determined bombers,” she added. “The rules under which the exercise were run gave advantages to bombers, and umpire rulings explained away unexpected, [inconvenient] results.”
Contrary combat evidence came soon after, starting in July 1936. The 33-month Spanish Civil War offered the opportunity to observe fighters demonstrate just how lethal they really were against bombers, and their ability to survive the bombers’ machine guns. The decidedly unfavorable bomber loss ratios experienced in Spain clearly foretold what American bombers would face in the next war.
“The escort of bomber formations proceeding to and from their objective by double, and more than double, their number of fighters, has been found by both sides to be a necessity notwithstanding the ability of the bomber to shoot down fighters,” Army officials declared, according to Biddle.
U.S. Army Cpt. Claire Chennault, the chief fighter instructor at the Air Corps Tactical School, argued the bomber was not immune to the “ancient principle that for every weapon there is a new and effective counter weapon,” Biddle explained. As a reward for his clear and prophetic tactical teachings, the Tactical School’s bomber leadership passed him over for promotion, prompting the officer to resign in 1937.
Ironically, that made Chennault available to train and lead China’s legendary Flying Tigers. Their brilliant combat record using his tactics vindicated all his ideas about the devastating effectiveness of small fighter groups against vastly larger Japanese bomber forces.
Just as the Army Air Corps leadership ignored Chennault’s ideas and results, its mindset would not brook an objective interpretation of the Spanish Civil War. The conflict suggested that fighter escort was essential to avoid unsustainable bomber losses.
The Army’s aviation branch certainly didn’t want to divert bomber money to buy escort fighters. With generals fixated on flying deep in an enemy’s heartland, the stronger objection was that the short range of available fighters prevented bombers from reaching these distant targets.
In truth, this was a self-inflicted wound. The Army’s P-47s and P-38s could indeed have escorted the bombers deep into Germany from the moment they deployed to Britain. Arnold made that impossible by prohibiting external drop tanks on fighters.
Since drop tanks cut into the bomb load he considered so all-important, “[i]n February 1939, Arnold forbid the development of a 52-gallon drop tank for the P-36 fighter because of ‘safety reasons’,” Trent Telenko wrote in a detailed post for the blog Chicago Boyz. “A fuel tank rack that had a 52 gallon fuel tank could carry a 300 pound bomb.”
Arnold did show occasional moments of clear tactical reasoning. In April 1940, he reviewed the recommendations of the board he had established to set priorities for the Army Air Corps.
The Emmons Board recommended, unsurprisingly, a very long range heavy bomber as its first priority. The fourth priority was an escort fighter with 1,500-mile range.
To Arnold’s credit, he swapped the first and fourth priority, moving long-range fighter escort to first place. The attacks on Pearl Harbor and the Philippines no doubt increased his incentives to solve the fighter range problem.
At a meeting on Feb. 20, 1942, “Arnold ordered the all-out development of auxiliary fuel tanks,” U.S. Air Force Maj. Robert Eslinger wrote in a research paper at the Air Command and Staff College. This decision came just two and a half months after Japanese Zero fighters used bamboo-and-paper drop tanks to escort bombers that wiped out America’s own Philippine-based B-17 bomber force.
Unfortunately, in the heat of his budget battles for more and larger four-engine bombers, the bomber general failed to follow up on the nickel-and-dime drop tank issue.
Eight months later, in October 1942 “… Eighth Air Force … inquired whether jettisonable fuel tanks could be made available for the P-47,” scholar William Emerson said in a lecture, titled Operation POINTBLANK: A Tale of Bombers and Fighters. “Nothing came of the request.”
“In February 1943 [another request was made],” Emerson continued. “It is not clear from the record what response was forthcoming to this request … but it is clear that little was accomplished up to June 29, 1943, when [Army Materiel Command] belatedly held a final design conference on P-47 auxiliary tanks.”
“On August 8, 1943, … [Army Materiel Command] had to confess that although some experimental types had been completed, none were yet available for use in operational theaters.”
Out of frustration, the Eighth Fighter Command in England made its own tanks. In addition, the unit hired local British craftsmen to make some out of glue-impregnated kraft paper.
Elsewhere, U.S. Army Gen. George Kenney’s Fifth Air Force in the Pacific developed its versions from old Spam cans. These tanks turned out better than the ones that finally arrived through official Army Air Forces channels.
Upon discovering this, Arnold wrote “there is no reason in God’s world why General Kenney should have to develop his own belly tanks,” according to Emerson. “If he can develop one over there in two months, we should be able to develop one here in the States in one month.”
Of course, it was Arnold’s failure to follow up on the issue that allowed 20 months to pass without anyone supplying a single U.S.-built belly tank to American fighter pilots in combat. The Army bureaucracy’s perennial hostility to ideas from the field — especially really cheap and embarrassingly effective ones — surely didn’t help matters.
Throughout World War II, the Army Air Forces bombarded the American public with press releases about the accuracy of the Norden bombsight and how it and the four-engine bomber would bring Germany to its knees. Both the gullible public and the politicians, believing in the integrity of high ranking officers, swallowed the propaganda about American bombers flying so high and so fast that enemy fighters and surface-to-air guns couldn’t possibly prevent them from destroying the Hun’s means and will to wage war.
Indeed, even before the war started, the Army was already pushing the idea of winning wars through air power without any need to send in the troops at all. American bomber generals, having preached that the B-17 was an invincible, self-defending flying fortress, couldn’t wait to start bombing Germany — even without fighter escort and drop tanks.
When the Eighth Air Force dropped the first bombs on German soil on Jan. 27, 1943, the mission exposed the mismatch between this concept and the brutal reality of war. The crews targeted the naval port at Wilhelmshaven in a raid involving more than 90 B-17 and B-24 bombers.
Only 58 bombers — 60 percent — found the target. The bomber force had no escort fighters, but crews claimed they shot down 22 German defenders.
German after-action reports show the Luftwaffe lost seven fighters — confirming the savvy air historian’s working premise that combat claims are usually exaggerated by a factor of pi. The Nazis shot down three bombers — five percent of those that reached the target — killing or wounding 35 American fliers, according to the official record.
This seemingly low loss rate was, in fact, already unsustainable due to the inexorable arithmetic of combat attrition. A five percent loss rate means you’ve lost half your bombers — and more than half your crews because of the extra casualties aboard the shot-up bombers that manage to limp home — after only 11 missions.
Far worse was yet to come.
U.S. Army Gen. Ira Eaker, in charge of the Eighth Air Force in England, persisted in launching bomber raids without escorts deep into Germany. Bomber losses mounted during spring 1943, running 80 per month between April and June and increasing to 110 per month by summer.
Eaker’s commitment to the strategy remained unshaken. In Fall 1943, he launched a major raid on an aircraft and ball bearings plants in and around Schweinfurt, followed by another against automotive factories in Stuttgart. The missions proved disastrous.
Eighth Air Force lost 19 and 17 percent of the bombers sent on each operation, respectively, along with 1,200 crew casualties. The bombing only reduced factory production by one third for a few weeks.
Oblivious to these crushingly unsustainable losses, in October 1943, the unit’s aircraft mounted a whole week of maximum effort bombing. This culminated in Black Thursday — Oct 14, 1943 — the nickname for yet another large Schweinfurt raid.
This attack proved even more brutal on American fliers than the first attempt. After the mission was over, the Eighth had to write off 26 percent of its bombers.
By this time, Eaker’s bomber losses were so high that he would have to replace his entire bomber force every three months — a clearly impossible proposition. Even worse, he would be losing 100 percent of his bomber crews every three months, as well.
In the graph above, the vertical red bars indicate the available bombers for the Eighth Air Force for a given month whereas the green and red line indicate the cumulative loss of bombers. Using the data from Williamson Murray’s Strategy for Defeat: The Luftwaffe 1933–1945, a quick scan indicates that Army bombers on hand were getting replaced too slowly to make up for losses starting in September 1943.
Black October and the 2,030 dead crews lost that month ended the myth of the bomber always “getting through” without the benefit of escorts.
For the nine months from that first raid on Wilhelmshaven through Black October, thousands of bomber crewmen died unnecessarily while British bases were chock full of fighters that could have protected them all the way to their German targets. To Arnold and his failure to implement his belly tank directive must go the responsibility for their deaths.
Black October made it obvious that losses of bombers and crews exceeded America’s ability to replace them. With the utter failure of the bomber mafia’s fanatical faith in the self-defending bomber exposed, Eaker had no choice but to abandon the unescorted bomber raids he had championed so relentlessly.
“With the Schweinfurt missions went the virtual end of the idea that the heavy bomber could ‘go it alone’,” the Air Force conceded in a 1955 history. “The debate that had continued since the early 1930’s was now all but over.”
“To reach targets in Germany would require more than a regrouping of bomber formations and an inculcation of an offensive spirit,” the review added. “These would help, but they were not answers to the German Me-109 and Fw-190 [fighter planes].”
“The Eighth Bomber Command’s Operational Research Section stated: ‘…enemy fighter activity is probably the sole cause of two out of five of our loses, and that is the final cause of seven out of ten of our losses.’”
Turning the bombers loose with fighters that could fly only a short distance was like providing a fire escape that went down to the fourth floor and, when fire broke out, forcing residents to jump the final three stories.
The Army suspended unescorted bomber raids until 1944. The order came from U.S. Army Brig. Gen. Fred Anderson, head of the Eighth Bomber Command, on Oct. 22, 1943, U.S. Army Maj. Greg Grabow explained in a Command and General Staff College thesis.
Two months later, like the deus ex machina of a Greek play, the Merlin-engine powered P-51B Mustang made its serendipitous debut in December 1943. The new escort fighter could fly almost as far as the bombers could bomb. Equally important, U.S. Army Gen. Jimmy Doolittle, a firm believer in the value of fighter escort, took over for Eaker.
On Dec. 11, 1943, the P-51Bs flew their first escort mission, bringing bombers to Emdem on the German coast, just short of Wilhelmshaven. Two days later the Mustangs escorted bombers on a raid deep into Germany, flying 480 miles to hit the German naval base at Kiel.
With P-51Bs providing escort, losses immediately dropped.
As Pentagon staff officers are fond of saying, “success has many fathers; failure is always an orphan.” Arnold was no exception.
In his post-war autobiography Global Mission, the officer took credit — with the help of an invented chronology — for allegedly fathering the early decision to draft the P-51 into Army Air Forces service:
Briefly, in 1940, “Dutch” Kindelberger, of North American, was asked to build P-40’s for the British. “Dutch” could not see his way to building P-40’s, so he had his engineers dig down in their files, pull out a substitute for the P-40. Our Materiel Division was not particularly interested, but they did say that if North American built these for the British, we were to get two P-51’s for nothing.
The first airplane was completed toward the latter part of 1940. Production was not started until the middle part of 1941 (Jane’s All the World’s Aircraft states December, 1941). When I went overseas in the Spring of 1941, Tommy Hitchcock and Mr. Winant talked to me about the P-51, although they didn’t know much about it at the time. Spaatz and I went out to the North American plant in January or February — anyway, early in 1942 — and it was then that we saw and inspected it and decided that we must have the P-51 for our own Air Force, in spite of the Materiel Division’s turning it down.
In truth, the Mustang’s birth and entry into World War II had nothing to do with the prescience of either Arnold or the Army. The general’s two paragraph explanation differs in important respects from several considerably more detached and detailed histories of the origins of the P-51, including Nelson Aldrich’s American Hero, Ray Wagner’s Mustang Designer, Jeff Ethell’s Mustang: A Documentary History of the P-51 and Lynne Olson’s Citizens of London.
A brief summary of their meticulously documented research into the evolution of the P-51 Mustang makes this very clear.
The Mustang was an example of chance favoring the prepared mind. In early 1940, officials in London set up the British Direct Purchase Commission to use American lend-lease funds to buy from American factories the weapons Britain most urgently needed — and to do so as quickly as possible.
With funds earmarked for a close support fighter — aka “army cooperation,” in British parlance — for the Royal Air Force, the commission decided to buy the in-production P-40 Warhawk. As it turned out, this aircraft was poorly suited for any form of ground attack.
However, the Army Air Corps warned the commission that the United States needed all the P-40s the Curtiss factory could produce. Instead, American officers suggested the British approach North American Aviation’s president James “Dutch” Kindelberger to see if his company might produce additional P-40s under license.
Kindelberger ran this idea by his brilliant young chief designer Ed Schmued, a naturalized citizen born in Germany. Schmued immediately replied he could design a much better airplane in three months. Many years later, one of the authors asked Schmued in interview if he had ever designed a fighter before.
“No, but I had been carrying around in my head concepts of what I would do if ever given the chance,” Schmued replied. “The design that became the P-51 is the result.”
The British accepted North American Aviation’s counter-offer to design and produce a completely new airplane for them on two conditions. First, North American had to deliver planes by January 1941 and second, the design had to use the same Allison engine as the P-40.
The British Direct Purchase Commission approved the contract on April 10, 1940 and the new prototype was on the runway 102 days after North American signed the document. Unfortunately, since Allison delivered engines three months late, the first flight only came on Oct. 26, 1940.
Production for the RAF started in early 1941 and the British named the production airplane the Mustang I. In August 1942, the first RAF Mustangs attacked Dieppe in France and enemy ships in the English channel.
In early 1943, the Army Air Forces sent the A-36 Apache version into combat in Italy. These aircraft were predictably vulnerable to even light anti-aircraft fire due to the liquid-cooled Allison engine.
In both RAF testing and in limited air combat over the channel, the Mustang Is showed some promise as an air-to-air fighter at low altitudes. Unfortunately, due to the Allison engine, the initial variant was decidedly inadequate for the high altitude bomber escort mission in the European theater.
Nevertheless, these disappointing early models led directly to the new and remarkably improved P-51 that saved Arnold and Spaatz’s failed bombing campaign. But neither Arnold nor Spaatz nor the Army’s procurement bureaucracy deserve credit for bringing the new, improved aircraft into American inventory.
Instead, it was an internationally-famous polo player, Tommy Hitchcock. He skillfully wielded his high level social and political connections to impose the P-51 on the reluctant bomber generals and a hostile bureaucracy.
Hitchcock came from a wealthy New York family, shot down two enemy planes as a volunteer pilot in World War I, got captured, escaped as a prisoner of war, spent the interwar years becoming what many considered the world’s best polo player, married into the Mellon fortune, served as the model for two of F. Scott Fitzgerald’s most glamorous characters and wanted to get back into the cockpit as soon as World War II broke out.
His age — 41 years old — prevented him from following through with that plan.
Instead, the closest he could get to the war was as the assistant air attaché in the American Embassy in London. On May 1, 1942, nearly five months after Pearl Harbor attack, Hitchcock arrived at the post with the Army rank of major.
Hitchcock served as liaison between the Eighth Air Force and both British forces and the U.K.’s aviation industry. Some Americans found it difficult to accept that the British might have better ideas.
So, one of Hitchcock’s primary functions was to sniff out and pass on useful British innovations without revealing their foreign origins. In this role, Hitchcock learned that a test pilot for Rolls Royce, Ronnie Harker, had observed the nearly identical dimensions of the Allison and Merlin engines.
Harker had been urging Rolls Royce management to drop the Merlin — the powerplant behind the famous Spitfire fighter plane — into the Mustang’s engine bay. Harker and Hitchcock had each flown the Allison-powered Mustang and were impressed with the Mustang’s maneuvering performance at low altitude.
Harker noticed that at similar horsepower settings, the Mustang was both 30 miles per hour faster than the highly regarded Spitfire and had three times the fuel capacity — both clear signs of greatly improved range. Since the Allison engine ran out of power at higher altitudes and the Merlin engine performed superbly there, the potential combat benefits were obvious.
Rolls Royce notified Hitchcock of the planned Merlin-Mustang conversion test. There is some evidence that Hitchcock was already thinking in the same vein and had passed his thoughts to North American Aviation.
Around the same time, the Packard Motor Company was completing negotiations with Rolls Royce for an American license to build the Merlin engine. On July 25, 1942, North American Aviation was authorized to convert two of the British Mustangs to Merlin engines.
American officials dubbed these two airplanes XP-78s, before renaming them as XP-51Bs shortly thereafter. Back in England, British authorities officially authorized the Rolls Royce Merlin-Mustang conversion project on Aug. 12, 1942.
On Oct. 13, 1942, the first converted Mustang took off. With the Merlin engine, the plane’s top speed leapt from 390 to 433 miles per hour, could climb rate of 3,440 feet per minute and had a range of up to 2,000 miles with external drop tanks.
On Nov. 30, 1942, the month after Rolls Royce tested the improved Mustang, North American flew its own version with the Packard-licensed Merlin engine — and got even better results. The XP-51B reached 441 miles per hour in level flight at 29,800 feet — 100 miles per hour more than a Mustang with the Allison motor.
On top of that, the Merlin doubled the Mustang’s climb rate. The P-51B was better in virtually every dogfighting performance characteristic than either of the two top performing German fighters, the Me-109 and Fw-190.
According to Global Mission, Arnold claims he saw military attaché Tommy Hitchcock in London in spring 1941. This was impossible because Hitchcock did not arrive in London until May 1942.
Arnold’s own diary confirms this. “Tuesday, May 26, 1942 Went to Claridge[’s] Hotel with [U.S. Ambassador Gil] Winant. Breakfast with Winant, Chaney and military attache.”
Although the general didn’t name the “attaché,” Hitchcock arrived on May 1, 1942. It is likely that Arnold was referring to Hitchcock when he wrote the entry.
“Long discussion with Chaney and Winant re [sic] efficiency of U.S. pursuit, P-39 especially,” Arnold continued in his notes. “Chaney doubts efficiency of both P-38 and P-39, thinks we are doing wrong by using either.”
And it appears Hitchcock shared what he learned about the Merlin engine — or that U.K. Prime Minister Winston Churchill had somehow learned about it separately. On Oct. 22, 1942, Churchill met with Arnold and raised a long list of staff-prepared issues for improving allied air operations, one of which was the Merlin-powered P-51.
Churchill “went on to recommend…the development of the P-51 Mustang fighter ‘with the right [Rolls-Royce] engines’,” Arnold noted.
Loaded with engineering estimates for Merlin-powered P-51 performance, in November 1942, Hitchcock flew back to Washington, D.C. to visit Arnold and share the good news. After the briefing, Arnold expressed tepid interest in the P-51, dismissing the data as merely “estimated.”
Hitchcock, un-cowed by four-star rank and not seeking a military career, went over Arnold’s head to Robert Lovett, then Assistant Secretary of War for Air. Presumably Lovett listened attentively.
Both men flew together in World War I. As fellow members of New York’s “400” social elite they often got together with other well-to-do individuals to play polo.
“Pressed hard by Lovett and others in the War Department, Arnold reluctantly gave in, ordering the production of an initial 2,200 P-51Bs, as hybrid Mustangs [with the British Rolls Royce engine] were called,” Olson wrote in Citizens of London. “But while the order was supposed to have the highest priority, there was a lag in producing the planes, and Arnold did little to speed it up.
“‘His hands were tied by his mouth’ Lovett noted,” according to Olson “[Arnold] said our only need was flying fortresses … [that] very few fighters could keep up with them.”
“But as Lovett added, ‘the Messerschmitts had no difficulty at all.’”
The troubling disparities between Arnold’s two paragraph account in his autobiography and the published Mustang histories are best summarized in the table below.
“It may be said that we could have had the long-range P-51 in Europe rather sooner that we did,” Arnold noted in Global Mission. “That we did not have it sooner was the Air Force’s own fault.”
His comment would have been more accurate if he had written: “That we did not have it sooner was my fault.”
In truth, with the right Army leadership priorities, the long range P-51B could have been in combat over Germany five months earlier, in July 1943. This assumes the planes would have been ready a conservative nine months after the first flight in October 1942.
With these fighters, the Eighth Air Force might have avoided devastating bomber and crew losses of the disastrous operations in summer and fall 1943. Even more importantly, Arnold could have added: “that our P-47s did not have the external tanks to accompany bombers deep into Germany far sooner was also my fault.”
Arnold mindset, which caused him to forbid drop tank development in 1939, doomed thousands of unescorted bomber crew members throughout all of 1943 to death and dismemberment. This needless slaughter remained unrelieved until the belated deliveries in 1944 of adequate quantities of drop tanks — and of long range P-51Bs.
Pierre M. Sprey is a co-designer of the F-16 fighter jet, was technical director of the U.S. Air Force’s A-10 concept design team, served as weapons analyst for the Office of the Secretary of Defense for 15 years and has been an active member of the military reform underground for the last 35 years.