History Friday — Revisiting the P-51 Mustang Historical Narrative

James Perry Stevenson and Pierre Sprey recently (Dec 2, 2016) wrote a column over on the War Is Boring media blog titled “Arrogant U.S. Generals Made the P-51 Mustang a Necessity — With better leadership, the iconic fighter plane might’ve been unnecessary” that used my September 2013 Chicagoboyz blog post “History Friday: Deconstructing the P-51 Mustang Historical Narrative” as a basis for a lot of their article with a link back to my Chicagoboyz post with a comment to the effect that it was a “detailed post.” Given who those two men are, that is the military history good housekeeping seal or approval. ***

Yeah Me!! — Glyph of a middle age fat man doing a happy dance!

Go over and check it out at this link:

“Arrogant U.S. Generals Made the P-51 Mustang a Necessity — With better leadership, the iconic fighter plane might’ve been unnecessary”

The 165 Gallon Lockheed Drop Tank in Front of a P-38 Lightning Fighter dated Nov 1943
A 150/165 Gallon Lockheed Drop Tank in front of a P-38 Lightning Fighter. Production of the tank increased from 300 in September 1943 to 22,000 in December 1943.

That said, it turns out their closing paragraph,

“Arnold’s mindset, which caused him to forbid drop tank development in 1939, doomed thousands of unescorted bomber crews 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 ranged P-51B’s.

….and my Sept 2013 blog post are going to need a rewrite thanks to my research partner Ryan Crierie’s latest find, a September 1943 fighter range chart from the Gen. Hap Arnold Microfilms Reel 122.

The “truth in the details” is that the tragically poor decision General Hap Arnold made in 1939 to halt the use drop tanks in the US Army Air Force that made the disaster the 2nd Schweinfurt–Regensburg mission inevitable was also the decision that made the P-51B technically possible.

The 2nd order effects of that procurement decision on the USAAF’s “technological development tree” gave Wright Field fighter development engineers the “design chops” to place in the P-51B the additional 85 gallon internal fuel tank that Mustangs used to reach Berlin in early 1944, when it was needed in late 1943.



High technology warfare, whether of the 1940s or the early 21st century is a three legged stool made up of technology, doctrine, training with a logistical support structure capable holding the three legs stable and properly balanced.  This is why the German Panzer Divisions with pop-gun 37mm gun armed tanks could overwhelm large numbers of the Soviet Union’s T-34 and KV-1 tanks in Operation Barbarossa (German: Unternehmen Barbarossa).  The Soviet tanks lacked the proper balance of doctrine, training and logistics to take advantage of their superior tank technology.

Similarly, the Eight Air Force’s October 14, 1943 Schweinfurt–Regensburg mission was where the USAAF’s adequately trained, logistically well supported bomber force, flying the superbly designed B-17 bomber and using the flawed self-escorting heavy bomber doctrine met a Luftwaffe that had put together the complete aerial combined arms team, a high tech “three legged stool” of radar controlled heavy rocket fighters (ME-110) and lighter Me-109/FW190 fighters with a doctrine of choreographed large formation attacks.  The results — 60 lost heavy bombers —  speak for themselves. The Luftwaffe demonstrated that it could destroy any unescorted Eight Air Force heavy bomber combat box formation, no matter the size, that lacked fighter escorts through out the entire mission.

The Luftwaffe’s Heavy twin and light single engine combined arms fighter force trumped an American single arm heavy bomber force. To quote the Australian Airpower Expert Carlo Dr Carlo Kopp, Associate Fellow AIAA, Senior Member IEEE, PEng and Co-founder, Air Power Australia: http://www.ausairpower.net/

The heavy bombers did inflict the critical attrition on the production base and POL. But they did so only once they were properly supported by escorts. Air power performs best when operated as an integrated whole. The ideologues tend not to accept this. Yes the historical record is unambiguous.

It took months after the 2nd Schweinfurt–Regensburg for the Eight Air Force to deploy its own “three legged stool” of fighter drop tanks, training in “Long of lean” fuel management techniques, and a _doctrinal change_ that allowed the use of existing fighters with droppable auxiliary fuel tanks. Fighters with drop tanks were used in three shifts to cover the bomber formations during

  1. Penetration of enemy air space,
  2. At the target area and
  3. During withdrawal,

…too which the long range P-51 was added.

The three shift fighter escort doctrine allowed USAAF fighters to drop external fuel tanks and dog fight for 30 minutes with full engine power with German fighters, while still protecting the bombers. Enemy fighters that attacked American fighters were not attacking US bombers, and enemy pilots dying in such fights did not come back to kill anything.

Drop tanks were the technological glue that allowed a USAAF offensive aerial combined arms team to develop.  Only large numbers of American daylight heavy bombers could deliver the payload to damage oil and aircraft production plant targets badly enough to make Luftwaffe fighters come up and fight. Only American fighter escorts could break up Luftwaffe fighter formations before they could organize a combined arms attack large enough to break bomber “combat box” formations.

The fighter penetration missions — organized in shifts — to cover the bomber formations required long range radar, VHF band frequency crystal modulated radio and radio intercept stations to track both our own aircraft and enemy fighter reaction to get the penetrating fighters to shield the bomber streams.  (The best resource I’ve found that explains the development of this  doctrine is Stephan McFarland and Wesley Phillip Newton’s “TO COMMAND THE SKY – The Battle for Air Superiority over Germany, 1942-1944” from the Smithsonian History of Aviation Series.)

However, the P-51B would still not have been able to play a role in this team – even with drop tanks – without the second order effects of Gen. Hap Arnold’s 1939 decision.

For which, see Ryan Crierie’s slide below:

A September 1943 range chart from Hap arnold Microfilm real 122. It shows various radius of action for fighters with combinations of internal fuel tank kits and the Lockheed 150 gallon drop tank.
A September 1943 range chart from General Hap Arnold Microfilm real 122. It shows various radius of action for fighters with combinations of internal fuel tank kits and the Lockheed 150 gallon drop tank. (Click on photo for a larger view)


The September 1943 slide above shows that both the P-51B and P-38Js fighters needed internal fuel tank kits to function as long range escorts.  And that new production P-47Ds could, with two 150 gallon Lockheed external tanks, escort B-17s the distance.  General Arnold acted swiftly after seeing that slide. Between September 1943 and December 1943 the 150 gallon Lockheed external tank production went from 300 a month to 22,000!!!  And hundreds of internal tank fuel kits were airlifted to England.

These internal tanks were added to P-51Bs in English fighter depots and shipment processing centers in the fall/winter of 1943-1944.   These were the planes that made the P-51 legend.

(The P-38J, on the other hand, was snake bit.  Its C-54, carrying all the available internal fuel tank kits for several months production, was shot down by the RAF in a friendly fire incident in the late fall of 1943.)

The story behind those kits comes from General Benjamin S. Kelsey in “THE DRAGON’S TEETH? — The Creation of United States Airpower in World War II,” and General Mark Bradely’s story “Bradley Vs. the P-75” in Penn Leary’s (editor) “TEST FLYING AT OLD WRIGHT FIELD – By The “Wright Stuff” Pilots and Engineers.”

General Kelsey explained in his book that while external drop tanks were outlawed, the operational requirement to move short ranged fighter’s long distances inside America remained.  To take up the slack of the now outlawed external tanks. Wright field engineers developed a series of temporary internal fuel tank kits replacing guns, ammo and just plain empty internal spaces for long range ferry flights.

This was a pain to do and finally Kelsey got General Arnold to reverse his safety policy by dint of pointing out the wartime requirement for shipping fighters to Europe versus the lack of shipping tonnage for same.  Arnold approved the use of Lockheed external fuel tanks for P-38 and P-47 ferry flights to Europe in 1943.


A 1943 ferry flight of a P-47D in Iceland with the early 150-Gallon version of the Lockheed drop tank, later uprated to 165 Gallons. — Page 16 “P-47 Thunderbolt in Action” Aircraft Number 67, Squadron/signal Publications”

General Mark Bradley’s tale is the story of his involvement with getting the 85 gallon fuel tank the P-51B, after the experience of test flying the General Motors XP-75 Eagle.  The “Eagle” was as misnamed a fighter design as could be imagined, it was built around a 24 cylinder Allison R2600-20 engine that was supposed to deliver 3,000 horsepower, but barely made 2,300 HP.  Its air frame had the wings of a P-40, the center section of a Vought design for the Navy and the tail of a Navy SBD dive bomber. It was big, clumsy, unstable in flight and its six bladed counter rotating prop was too heavy.  Even if it could get the range needed for a long range escort, it could not defend itself when it got to a German target.

Bradley’s P-75 experience saw him become part of the P-51 mafia and he saw to it that the 85 gallon internal tank was added to the P-51B and tested at Wright Field.

Wright field engineers, without  the 1939 to 1943 experience with internal fuel tank kits caused by General Hap Arnold’s 1939 decision, would not have been in the position to rapidly make the P-51 into the long range escort fighter it eventually became.

And now you know why James Perry Stevenson and Pierre Sprey and I need to do  article rewrites.



***  James Perry Stevenson is the former editor of the Topgun Journal and the author of The $5 Billion Misunderstanding and The Pentagon Paradox.


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.


Sources and Notes                

Mark Bradely “Bradley Vs. the P-75” pages 23 – 26 in Penn Leary’s (editor) “TEST FLYING AT OLD WRIGHT FIELD – By The “Wright Stuff” Pilots and Engineers,” Wpasb Educational Fund; 2nd edition (May 1995), ISBN-13: 978-0961791728

Robert A. Eslinger , “THE NEGLECT OF LONG–RANGE ESCORT DEVELOPMENT DURING THE INTERWAR YEARS (1918–1943)”, 1997 (E-book) and 2012 (Paper) ISBN-13: 978-1249415558, http://www.dtic.mil/dtic/tr/fulltext/u2/a393237.pdf

Drop Tanks
Adding external fuel tanks to existing pursuit aircraft seemed like a logical solution to extending pursuit range. Making the tanks dropable in flight preserved maneuverability and performance when required for combat. Experiments with dropable fuel tanks had been conducted throughout the 1920s and 1930s. The greatest concern about drop tanks was the hazard of fire. In February 1939, Curtiss–Wright wanted to test a 52–gallon tank mounted on the bomb rack of a P–39C, but the “Chief of the Air Corps directed that no tactical plane be equipped with a dropable fuel tank” because of the potential for fires.18″

COL. WALDO H. HEINRICHS, A.C., A.U.S.,, INTELLIGENCE OFFICER (A-2) 66TH FIGHTER WING “A HISTORY OF THE VIII U.S.A.A.F. FIGHTER COMMAND,” WITH A FOREWORD BY MAJOR-GENERAL WILLIAM E. KEPNER, COMMANDING GENERAL, dtd 31 OCT 1944, link: http://cgsc.contentdm.oclc.org/cdm/compoundobject/collection/p4013coll8/id/317/rec/116 Accessed 9/21/2013

Benjamin S. Kelsey, “THE DRAGON’S TEETH? — The Creation of United States Airpower in World War II,” C 1980 Smithsonian Institute Press, Washington D.C. ISBN 0-87474-574-8

Stephan McFarland and Wesley Phillip Newton’s “TO COMMAND THE SKY – The Battle for Air Superiority over Germany, 1942-1944” Smithsonian History of Aviation and Spaceflight (Paperback) (Book 45879), University Alabama Press (March 6, 2006), ISN-13: 978-0817353469

Trent J. Telenko, “History Friday — MacArthur’s Fighter Drop Tanks,” 12 July 2013, https://chicagoboyz.net/archives/37392.html

Trent J. Telenko, “History Friday: Deconstructing the P-51 Mustang Historical Narrative, September 27th, 2013, https://chicagoboyz.net/archives/38801.html

17 thoughts on “History Friday — Revisiting the P-51 Mustang Historical Narrative”

  1. The P 38, which was perfect for the Pacific, still had a couple of flaws that were not fixed until the J model. One was the lack of a reliable cockpit heater. The engines were in the wings and the cockpit heater did not work well in cold European skies.

    The second flaw was the compressibility problem.

    From the specifications:

    Tricycle undercarriage was specified as preferred and large internal fuel capacity was mandatory, to circumvent an administratively imposed ban on the use of drop tanks by fighters.

    The 322 had by that time also demonstrated problems due compressibility in dives which caused ‘Mach tuck’, a severe nose down pitching moment due to the aft of the CoP. This often led to the breakup of the aircraft and usually, loss of the pilot. Like prop rotation sense impaired engine out handling. The 322 affair escalated into a major dispute between Lockheed and the RAF and in the end, all Lightning I airframes were transferred to the USAAF which used them as trainers, under the designation of P-322. The turbocharged Lightning IIs became USAAF production P-38Gs.

    To aggravate these problems, inadequate cockpit heating resulted in severe pilot frostbite, while the Luftwaffe quickly learned about the compressibility problems in dives, with German pilots evading the P-38s by executing a split-S at high speed. The initial roll rate was not spectacular and the easily recognized planform provided the Luftwaffe with yet another advantage to play.

    Training was also a problem.

    Many of the P-38 handling techniques developed in the SWPA to counter the highly manoeuvrable and skilled Japanese opposition, such as differential throttle and rudder assisted roll entries, were never practiced widely in the ETO.

  2. Mike K,

    The two biggest problems with the P-38 was the lack of a second factory for them (until the summer of 1945) that would have allowed faster cut in of design changes and the lack of a multi-engine, tricycle landing gear, transition trainer between the AT-6 Texan and the P-38.

    All such trainers were reserved for B-24 training and the B-26 Marauder suffered higher accident rates from that same lack because of its higher wing loading and speed.

  3. Great work Trent. And God bless those boys at Wright Field. Solving problems they didn’t even intend to solve saved us all. Here’s to the nerds and tinkerers.

  4. I always enjoy reading these history posts. I’ve never heard much about the P-47 so I went looking for details. It was a monster, with that rear-mounted turbocharger and all the associated piping.

  5. “the B-26 Marauder suffered higher accident rates from that same lack because of its higher wing loading and speed.”

    The B 26 was a widow maker from the start and it was immediately discontinued in active service when the war ended.

    The P 38 could have used the Merlin engine, too and the cooling system was too efficient for European skies in winter.

  6. This past summer a P-51 was on display near us. I just looked at it because I wasn’t about to pay $2000 for the half hour flight. I found out about this event when I came home on Friday afternoon, and just as I stepped out of my car the B-17 emerged above my neighbors tree line and flew directly over my house. I was surprised to say the least. I was trying to think how they must’ve felt in old Hammerbrook when hundreds came over to set the city on fire.

  7. I flew in a B 17 and a B 24 and took my son on the B 17 for his birthday present.

    The P 51 was not much of an attraction but there was a Spitfire when I visited Duxford a few years ago, It was a trainer with two seats. That would have been fun.

  8. The 1962 Harmon Memorial Lecture was titled — “Operation POINTBLANK: A Tale of Bombers and Fighters” and is currently at this link :


    The issue with the Air Superiority campaign was covered well in the lecture and specifically it mentioned the drop tank issue.

    Basically, the average plane that killed most of the German aces, group, staffel and flight leaders in 1944 was a P-47 with a pair of 150 gallon drop tanks.

    The P-51’s showed up in overwhelming numbers -after- the Feb-Mar-April 1944 period where the aces and long flight time Luftwaffe pilots were killed.

    The P-51’s had the glory of killing off the the twin engine rocket and night fighters over Germany and wiping out the low flight time fighter pilots that showed up after that period.

  9. This is clipped from the link I posted in the comments above —

    The issue of range extension turned on two matters: an increase in the internal fuel tankage of the P-47, a problem solved easily enough, and the development of external, droppable fuel tanks suitable for combat. Now, auxiliary fuel tanks were not an easyproblem technically. What is more important, the question got bogged down in perhaps the most thorough Air Force bureaucratic muddle of the Second World War. As early as October 1942, Eighth Air Force had inquired whether jettisonable fuel tanks could be made available for the P-47. Nothing came of the request.

    In February 1943, an Assistant Chief of Air Staff, Brig. Gen. Benjamin Chidlaw, requested information from the Air Materiel Command at Wright-Patterson Field about the status of the P-47 belly tank program, among others. It is not clear from the record what response was forthcoming to this request from Wright-Patterson, but it is clear that little was accomplished up to June 29, 1943, when AMC belatedly held a final design conference on P-47 auxiliary tanks, among others under development. On August 8, 1943, however, AMC had to confess that although some experimental types had been completed, none were yet available for use in operational theaters.

    Meanwhile, VIII Fighter Command had developed its own belly tanks by means of contracts with local suppliers, despite shortages of materials in England which forced the English suppliers to fabricate the tanks out of a kind of cardboard. V Fighter Command did the same, producing amid the New Guinea jungles-presumably from old Spam cans – an auxiliary tank for P-47s superior to that produced, belatedly, by Wright-Patterson. General Arnold, who himself had only lately seen the importance of combat range extension, was disconsolate at this. “There is no reason in God’s world,” he wrote, “why General Kenney should have to develop his own belly tanks. If he can develop one over there in two months, we should be able to develop one here in the States in one month.”27 In fact, it took eleven months. Not until Mr. Lovett’s return from England in June 1943, was the program pursued with any ergency. Even so, it was pursued by fits and starts; in September 1943, it was found that monthly production of the 150-gallon belly tanks for the P-47 was only 300, as against Eighth Air Force requests for 22,000. Not until December 1943 did production begin to approximate the plangent and obvious needs of the situation.

    All these delays in a program so long under development and so vital to our air strategy are inexplicable – and indefensible. Materiel development should anticipate and forestall the needs of field commanders; at least, it should seek to accommodate them. In the matter of auxiliary tanks, the Air Materiel Command lagged far behind events and, for that matter, explicit requirements. It is difficult to dissent from the opinion of Brig. Gen. Hume Peabody, who examined the matter for General Arnold in August 1943 and reported that “it indicates a lack of forward thinking.”

    The effects of increased internal tankage and auxiliary tanks on the combat capabilities of the P-47s were extraordinary. On its first entrance into action on escort missions, on May 4, 1943, the Thunderbolt’s range had been about 175 miles; its deepest penetration prior to the development, by VIII Air Service Command, of English – produced auxiliary tanks had been on July 17 when “Jugs” had taken the bombers as far as Amsterdam, about 200 miles. On July 28, using the British cardboard tanks- which restricted altitude to 22,000 feet – they went all the way to Emmerich, 260 miles from their bases, an exploit which greatly discomfited German fighter controllers and, even more, German fighter pilots who encountered them for the first time so far inland. On September 27, the longlegged “Jugs” proved their mettle and underlined the importance of escort. On that day, they took the B-17s all the way to Emden and back. As a result, bomber losses on that mission were only 3% of the attacking force, far below the prevailing averages. By March 1944, the combat range of the P-47s had been extended all the way to Helmstedt, over 400 miles from their bases in East Anglia.28 By January 1944, indeed, most of Western Germany had come within P-47 range. This was crucial. The February air battles, which saved Operation POINTBLANK, were fought almost entirely by Thunderbolts. And they remained the Eighth Air Force’s workhorse fighter until gradually supplanted by the P-51 during the summer of 1944. I hope you will not take it as merely the maunderings of a former “Jug” pilot if I observe that it was the “Jug” that first put the German Fighter Command back on its heels. Others were to exploit the victory; the P-47 won it.

  10. I was surprised at learning of the combat radius of the Me109 and the Spitfire – maybe 300 miles?

    The drop tank gave the Mustang such range – did they ever develop a drop tank for the Spitfire?

    They had the same engine and the same basic airframe.

  11. The Spitfire and the ME109 did not have laminar flow wings and neither one had a lot of internal fuel storage.

  12. The reason there was not a long range Spitfire is that the British did not think it was possible.



    This from Jeffrey Quill’s ‘Spitfire , a test pilot’s story’

    Long range escort was the role in which the Merlin Mustang was particularly excellent because of the large load of fuel it was able to carry. True, the Spitfire Mk VIII, in service in 1943, was carrying additional fuel in its wing roots and also in jettosonabale tanks under the fuselage, but it was serving overseas and the problem of accommodating larger loads of fuel in the Spitfire at home was acute. The only available space was in the fuselage behind the pilot, but a tank of significant size there would have a major effect on the centre of gravity.

    However, it seemed to both Joe Smith and myself that, for the purpose of escorting bomber formations in daylight, a degree of longitudinal stability in the early stages of a sortie would be acceptable. Therefore the fuel in the rear fuel tank could be used for take off and climb and during the early stages of the sortie, the main tanks and wing tanks remaining full. In this case the centre of gravity would be moving forward to an acceptable position by the time the aircraft reached hostile airspace. It was decided therefore to embody a rear fuselage tank in a derivative of the MkXIV shortly due to come into production, the Mk XVIII.

    In the meantime a 75-gallon tank was fitted in the fuselage of a Mk IX behind the pilot and we also fitted a bob-weight in the elevator circuit, so what with this and the large horn-balance on the elevator we hoped for the best. However the best and most expedient way to test this aeroplane was to fly it a good long way and see how everything worked. So I took off from High Post on Salisbury Plain with all tanks full, carrying a 45-gallon drop tank in addition, and set off at economical cruising boost and RPM in the general direction of Scotland. The weather was unsettled, so I decided to fly at low altitude which was not, of course, a favourable height for optimum air miles per gallon: but I thought that if I could fly a distance equivalent to John o’Groats and back non-stop at that rather unfavourable height, keeping to the east of the Pennines and the Grampians, it would be a useful demonstration.

    The aeroplane was unstable to start with, but as soon as I had used up the rear fuselage fuel the handling was back to normal and I settled down to a long and enjoyable flight over a great variety of countryside from Salisbury Plan to the Moray Firth and back again, all below 1,000ft. In distance, and not taking into account the various diversions for weather and terrain, it was the equivalent to flying from East Anglia to Berlin and back. It took five hours.

    This flight demonstrated, if nothing else, that there was no fundamental reason why the Spitfire should not be turned into a long-range escort fighter provided that certain problems could be solved.

    A demonstration of this basic fact was also given by the Americans. They had two Mk IX Spitfires at Wright Field and by local modification they added two Mustang overload fuel tanks under the wings and some additional fuel inside the wings. They flew them across the Atlantic by the Northern Route – via Greenland and Iceland – and eventually they were thoroughly examined by the Supermarine design department. Unfortunately some of the structural modifications carried out were detrimental to the strength of the aircraft and so could not be considered for production

    They seemed to have the same reasoning as the long range Mustang designers did as that was unstable at the start of the mission and take off was rather long – I think Chuck Yeager had a close call incident with his Mustang that Len Deighton used in his book ‘Fighter’.

  13. “it was the “Jug” that first put the German Fighter Command back on its heels. Others were to exploit the victory; the P-47 won it.”

    I still remember a movie about 1948 called “Fighter Squadron” which was the story of drop tanks. Edmund O’Brien was in it. Along with Robert Stack.

  14. Yup. It was the last movie I can remember my father seeing, too. He was not much on movies or, for that matter, doing things with kids.

    It was pretty good. I remember a lot of it and haven’t seen it since 1948.

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