A Change in Doctrine after Schweinfurt

P-51D 44-14733 “Daddy’s Girl” as flown by Maj. Ray S. Wetmore of the 370th FS, 359th FG, from East Wretham in late 1944/early 1945.

Ronnie Olsthoorn Aviation Art

It was apparent to the USAAF leadership that long range fighter escort was needed and this would be answered in the upcoming months. In the summer of 1943, America’s aircraft production was focused on bombers first, reconnaissance aircraft second, and “other air force activities” third. The second Schweinfurt raid, October 14th 1943, changed aircraft production priority to fighter production with a focus on the P-38 and the P-47 at the time. Arnold ordered all P-38 and P-47 fighter groups deploying overseas to be sent to Britain but it took time to receive aircraft, train aircrews and emplace the necessary technical support. In the meantime, Major General Ira Eaker sent Eighth Bomber Command out on relatively short missions, within fighter escort range, encountering bad winter weather much of the time instead of the Luftwaffe. But when the Luftwaffe was encountered, the P-38 Lightning had trouble handling the highly maneuverable German fighters due to the Lightning’s turbochargers performing badly at higher altitudes in the high humidity and colder temperatures. The P-38 performed well at lower altitudes in the Mediterranean and Pacific Theaters, but was not suited for colder temperatures found at higher altitudes in north and central Europe. The USAAF leadership pinned hope that the P-38 would be the solution to the long range escort problem but mechanical difficulties blocked that option.

A more successful solution to answer the call for increased fighter escort range came in the form of external auxiliary fuel tanks for fighters. As early as 1942, the Eighth AAF inquired whether jettisonable fuel tanks could be made available for the P-47 but the solution was foolishly delayed by the industrial bureaucracy and the lack of emphasis by the USAAF leadership. Meanwhile, local sources in England were tapped to produce a limited quantity of 75 gallon tanks for both the Spitfire and the P-47. Due to the shortage of wartime material in Britain, these 75 gallon tanks were often made of inferior material and had mechanical issues at higher altitudes. By August of 1943, Army Material Command (AMC) was still experimenting at a slow pace with external tanks but had yet to produce its own model. It took a desperate plea by the Eighth’s technical service section chief, Colonel Cass Hough, to get the external fuel tank program kick started. Due to further political pressure applied by the Combined Chiefs, a suitable 150 gallon drop wing tank was quickly developed. In September of 1943, the monthly production of 150 gallon wing tanks for the P-47 was only 300; by December it was 22,000. If the tasking was taken seriously a year earlier, this one innovation could have decreased bomber losses during the fall of 1943 but emphasis arrived too late. As Brigadier General Hume Peabody would put it, the auxiliary tank problem indicated “a lack of forward thinking.” By early 1944, the 150 gallon wing tanks had a significant impact on the fighter escort solution.

Also by late fall of 1943, the P-47 received technical upgrades, which included an improved paddle bladed prop and a water injection boost kit, which greatly improved horse power and overall performance. The P-47 could now out-climb its main adversary, the FW-190, and with a new gyro-stabilized gun sight would have a better chance of obtaining hits. The P-47, a seven ton plane equipped with eight fifty caliber machine guns, had its combat range greatly increased by the new 150 gallon droppable wing tanks and performed a majority of the escort missions in early 1944 that swept the Luftwaffe from the skies. Even though the USAAF leadership placed a lot of faith in the P-38 Lightning, it was an entirely new plane that would take center stage for fighter escort duty. The origins of the P-51 are curious enough; in April 1940, the British Air Commission approached North American Aviation for a contract to build Curtis fighters for the RAF. The company suggested an entirely new plane be built and presented the NA-73 Mustang powered by an Allison engine – a prototype completed in only 127 days. The British Air Commission was delighted with the quick turn around and awarded North American with a contract. Before the Japanese attack on Pearl Harbor, 620 Mustangs were shipped to the RAF and made their debut during the Dieppe Raid in the summer of 1942. However, due to the underpowered Allison engine, their performance was not particularly impressive. For this reason, the P-51As were confined to low level tactical missions.

In May of 1942, trials were made with five P-51 aircraft outfitted with Rolls Royce Merlin 61 engines in an attempt to improve performance. The results with using these existing components were phenomenal, the P51B (production model) had improved performance at all altitudes especially above 33,000 feet obtaining speeds of 440 m. p. h.. Further adjustments in the controls resulted in improved maneuverability which led to an aircraft equal to or superior, in many aspects, to what the Luftwaffe could offer at the time. North American Aviation received a contract to build the more effective Merlin-61 engine and mate this to its successful airframe in North American’s aircraft manufacturing facilities.

By June 1943, 145 P51Bs were shipped to England but served in a reconnaissance role. Sixteen days after the October Schweinfurt raid, Arnold ordered all P-51Bs in England to be withheld from the reconnaissance role, transfer to the fighter escort role, and top priority was given to North American Aviation to produce more Mustangs. The British also agreed that all RAF squadrons, scheduled to convert to P-51 Mustangs, would support Eighth Bomber Command. It was not until the summer of 1944 that P-51s squadrons were ready for combat in numbers so the weight of the spring 1944 air battles fell upon the P-47.

When Lieutenant General Jimmy Doolittle took command of the Eighth AAF in December 1943, he made two important changes which at first were unpopular with the heavy bomber crews. First, he increased tours from 25 to 30 missions which upgraded aircrew experience and provided additional cadre for the build-up in new aircrews. Second, despite violent protests from Bomber Command, Doolittle released additional fighters from escort duty to seek out the Luftwaffe whether located in the air or on the ground. Under the old fighter escort system, the fighters would rendezvous with their respective bomber formation to give coverage but the fighters would have to constantly weave, to match the bomber’s speed, and this burned precious fuel. Doolittle’s new system called for relays of fighters to take turns covering the bombers while at the same time taking advantage of each type of fighter’s strength. The Spitfires would escort the bombers from the channel out to 100 miles then the P-47s would take over for the next 150 to 200 miles. Finally, the P-38s would escort the bombers for another 150 to 200 miles. Together, this phased escort system would provide coverage out to 450 miles. As a rule, only one-third of fighters needed to stay near the heavy bombers and escort fighters were rotated in by relays so precious fuel would not be burned by weaving to match the heavy bomber’s speed. The arrival of the P-51B Mustangs in numbers, along with 150 gallon wing tanks, would stretch fighter escort coverage out to 600 miles which was more than enough to reach Berlin. Doolittle’s new escort system was devised to give the bombers maximum coverage while at the same time striking the Luftwaffe where it hurt.

Once a fighter group finished its escort task, it could drop down to lower altitudes to strafe enemy airfields. This change in tactics, combined with the increase in Allied fighter escort range, would have a huge impact on the Luftwaffe and disrupt the German practice of rearming and refueling for additional sorties against heavy bombers and eventually account for an irreversible attrition on Luftwaffe pilots. For the first time, Eighth Fighter Command was released to perform their true offensive role.

Once the Eighth AAF restarted its daylight strategic bombing campaign in February 1944, Schweinfurt was revisited utilizing a combined bombing strategy. On the night of February 24th, 1944, RAF Bomber Command targeted Schweinfurt. The next morning Eighth Bomber Command, this time escorted by long range fighters, followed up with a daylight raid. Again that night, RAF Bomber Command committed a consecutive night raid that added to a total of 3,000 tons of high explosives onto the Schweinfurt ballbearing facilities. The Combined Bomber Oensive was now better coordinated and could have achieved devastating results. Unfortunately, Sir Arthur Harris, was correct in assuming the Germans dispersed their anti-friction industry by this time as the VFK Works transferred 549 vital machines (from all five factories) to new locations. Thus, the damage from these consecutive raids was not what the Allies hoped.

By April 1944, Eighth Fighter Command was ordering new low level fighter sweeps, some in conjunction with bomber missions, deep into Germany. By design, low level fighter sweeps were to catch German aircraft landing, taking off, or on the ground. When heavy or medium bombers were available, the bombers would release ordnance over the German airfields to help neutralize anti-aircraft fire before the fighters strafed. As the spring months wore on, the effects on the Luftwaffe became noticeable as the Luftwaffe was knocked off balance and air superiority turned over to the Allies. At the same time, the German general staff made a serious mistake which threw away any chance of the Luftwaffe regaining air superiority. In face of mounting pressure from the new fighter sweeps, the Germans withdrew their fighters back into Germany in an effort to find a haven and concentrate on Allied bomber formations. By doing so, the Luftwaffe lost its chance to strike Allied escort fighters near the channel and force them to drop their auxiliary tanks early. As it stood the P-47s, and later the P-51s, increased their combat radius further into Germany and soon there was nowhere for the Luftwaffe to hide.

The Germans recognized their fall 1943 victory over the Eighth AAF and many on the German general staff believed they stopped the Americans from attacking inside the borders of Germany. Although some Luftwaffe commanders, including General Hubert Weise (who commanded the air defenses of central Germany) were clearly worried, Goring and his staff believed it was impossible for Allied fighters to escort bombers east of Brunswick so they focused their operations on attacking unescorted heavy bombers. Because of this faulty escort range assumption, the Luftwaffe would later be unable to quickly change tactics or equipment (by this time German twin engine fighters were more vulnerable

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