Normandy: June August 1944[edit]

Geoffrey Page, commander of 125 Wing of the Second TAF, about to take off on a sortie fromLongues-sur-Mer, Normandy in his Spitfire Mk IXE 'AGP' with a 500-lb GP bomb under the fuselage and two 250-lb GP bombs on wing racks (1944)After the Normandy landings, some Spitfires (Griffon and Merlin engine marks) were retained in Britain to counter the V-1 flying bomb offensive in mid-1944 as part ofthe ADGB.[90]Supplies of a new aviation fuel, which was called "150 Grade", arrived from America in March 1944 and sufficient quantities were available to be used by ADGB fighters as the V-1 offensive started. The new fuel enabled theRolls-Royce MerlinandGriffonengines to operate at higher boost pressures, especially at lower altitudes, for the duration of the anti-V-1 campaign.[91]The bulk of the Spitfire squadrons, which by D-Day were incorporated into theSecond Tactical Air Force, were progressively moved across the Channel, operating fromforward airfieldsinNormandy, close behind the front-lines. From late August 1944, as the Allied ground forces overran German forces in France and moved forward intoBelgiumand parts of theNetherlands, the Spitfire units of 2 TAF moved to new airfields in support.[92]By this time, asair supremacy(as opposed toair superiority) had been achieved, and in line with 2 TAF's doctrine on the use of fighter-bombers most of the Merlin engined Mk IX and XVI units were used in thefighter-bomberrole.[69]This meant that these units concentrated on roaming over German territory, attacking ground targets of opportunity and providing tactical ground support to the army units. In this role there were fewer opportunities to engage Luftwaffe fighters.[93]A notable incident occurred on 17 July 1944, when a Spitfire of 602 Squadron attacked the staff car ofGeneralfeldmarschallErwin Rommel, wounding him and removing him from command ofArmy Group B.[94]One tactical innovation adopted by 2nd TAF Spitfires was the "Fluid Six"' formation, which had been developed through combat experience in Europe and North Africa. The first use of the tactic dated back to at least November 1941. It is known thatNo. 112 Squadron RAFused this in theNorth Africancampaign.[95]This formation "was considered the best fighter formation of the war".[96]It abandoned the leader-wingman combination that had existed before. Instead, it was based on three pairs of Spitfires which could provide mutual cover and support: the pairs were 'stacked' in altitude so that the pair (e.g.: 5 & 6) flying up-sun, and covering the tails of the leaders (1 & 2), flew higher, while the other pair (e.g.: 3 & 4) flew lower. Any attacking aircraft could be sandwiched between two pairs of Spitfires, no matter the direction or altitude of the attack. Another advantage of this formation was that when operating at squadron strength a flight commander was able to lead six aircraft of his own flight, "whereas, with formations of four there would more likely be one formation from each flight with the third consisting of aircraft from another flight."[96]

'Fluid Six' formation as flown by Spitfires of 2nd TAF 1944-1945The Merlin's water and glycol cooling system, as with all liquid-cooled aero-engines, proved vulnerable to small arms fire, with one hit in the radiator or coolant pipes often being enough to drain the system, eventually causing the engine to seize or catch fire. Although some pilots were able to gain enough altitude to glide back to a forward airfield, the low altitudes normally flown during ground attack missions meant that light (up to 30mm) flak claimed most of the Spitfire IXs and XVIs lost while operating as fighter-bombers.[97][98]Just 21 of the 152 Spitfires that were destroyed or damaged from all causes from 130 June 1944 were shot down by German fighters.[99]Flight LieutenantRaymond Baxter, who had flown Spitfires almost continually since 1941, flew Mk XVIs on fighter-bomber operations while commanding 'A' Flight of602 SquadronattackingV-2 rocketlaunching sites in theNetherlands: