Spit­fire Dive-Bomber

Great Fighter, Lousy Bomber

Flight Journal - - CONTENTS - By Don­ald Ni­jboer

The Su­per­ma­rine Spit­fire is re­garded by many as the finest sin­gle-seat fighter of World War II. Im­mor­tal­ized dur­ing the Bat­tle of Bri­tain and well known for its de­fense of Malta dur­ing 1942, the Spit­fire would see ac­tion on ev­ery British front dur­ing the war. Orig­i­nally de­signed as a short­range in­ter­cep­tor, the Spit­fire was one of the best, but as the war sit­u­a­tion be­gan to change, more de­mands were made of this el­e­gant air­frame.

A Great Multi task er… Usu­ally

As a fighter, the Spit­fire was well known for its speed and ma­neu­ver­abil­ity. Its great­est at­tribute, how­ever, had noth­ing to do with its ex­cep­tional per­for­mance. Re­flected in R. J. Mitchell’s bril­liant de­sign was the ca­pac­ity for con­tin­ued de­vel­op­ment. What set the Spit­fire apart from the

Hawker Hur­ri­cane and the mus­cle-bound Typhoon was its abil­ity to take on more horse­power with­out de­grad­ing its per­for­mance.

In­deed, ev­ery new Spit­fire mark was es­sen­tially a sim­ple in­crease in horse­power. The Spit­fire

Mk V was es­sen­tially a Mk I with the more­pow­er­ful Mer­lin 45 en­gine, and the Mk IX was a Mk V with the new Mer­lin 61 en­gine. For­tu­nately for the British, the Spit­fire’s abil­ity to ac­com­mo­date the more-pow­er­ful en­gines meant they had a fighter ca­pa­ble of tak­ing on the Luft­waffe’s lat­est Bf 109s and FW 190s. One can only imag­ine what might have hap­pened if the Spit­fire’s de­vel­op­ment ended with the Mk I or Mk V.

Like many com­bat air­craft of WW II, the Spit­fire was soon mod­i­fied to per­form a num­ber of roles for which it was never in­tended. Start­ing out as an in­ter­cep­tor, the Spit­fire was soon mod­i­fied into a long-range es­cort fighter (60 Mk IIA long-range fight­ers were built with a 40-gal­lon fixed tank un­der the port wing), photo-re­con­nais­sance air­craft, air su­pe­ri­or­ity fighter, and car­rier-borne fighter. It was even mod­i­fied with floats and tested as a float­plane fighter. That was a lot to ask of one air­frame, and in the end, there were two roles in which the Spit­fire per­formed rather poorly. The first was as a car­rier-borne fighter. Never in­tended for car­rier op­er­a­tions, it suf­fered from poor range and a high ac­ci­dent rate. Iron­i­cally, once free of the car­rier deck, the Seafire was con­sid­ered to be one of the best low- to medium-al­ti­tude naval fight­ers of the war. The sec­ond was as a di­ve­bomber. R. J. Mitchell never en­vi­sioned the Spit­fire as a fighter-bomber. So when the Royal Air Force (RAF) con­sid­ered the Spit­fire as a dive-bomber, it couldn’t have picked a worse air­craft.

A Bad Idea Be­gins

The evo­lu­tion of the Spit­fire into a dive-bomber be­gan shortly af­ter the fall of France in 1940. Al­though still con­vinced that strate­gic bomb­ing would win the war, the RAF quickly re­al­ized that air sup­port for the army had to be im­proved. De­vel­op­ments in North Africa would also con­trib­ute to the air sup­port ques­tion. Af­ter the two failed at­tempts to re­lieve the port of To­bruk in May and June of 1941, Air Vice-Mar­shal Arthur Ted­der and Gen. Sir Claude Auchin­leck moved ahead with a se­ries of ex­er­cises de­signed to solve the prob­lem of air sup­port for ground forces. This led di­rectly to the for­ma­tion of the Desert Air Force—the Al­lies’ first Tac­ti­cal Air Force (TAF) and the first time Spit­fires would carry bombs.

By early 1943, plan­ning for the D-Day in­va­sion was well ad­vanced. Both the RAF and the British Army were fi­nally singing from the same song­book and fully en­dorsed the for­ma­tion of the RAF’s Al­lied Ex­pe­di­tionary Force in May 1943. By Novem­ber, it was re­named the “2nd Tac­ti­cal Air Force” and in­cluded No. 2 Group (trans­ferred from Bomber Com­mand) and No. 83, 84, and 85 groups. The vast ma­jor­ity of air­craft found in the

THE SPIT­FIRE’S GROUND-AT­TACK CA­PA­BIL­I­TIES WERE LIM­ITED BY ITS LIGHT GUN ARMAMENT. THIS WAS REC­OG­NIZED BY THE AU­THOR­I­TIES, AND BE­FORE THE IN­VA­SION, THERE WAS A BIG PUSH TO UP­GRADE THE SPIT­FIRE’S ARMAMENT.

2nd TAF were sin­gle-seat Spit­fire IXs and Typhoon IBs. While the Spit­fire Mk IX was a great fighter, in many re­spects, it was ill suited for the groun­dat­tack role. At this stage of the war, the in­ef­fec­tive­ness of the 0.303-inch ma­chine gun was well known. While the 20mm can­non was an ef­fec­tive weapon against both air­craft and most ground tar­gets the Spit­fire’s ground-at­tack ca­pa­bil­i­ties were lim­ited by its light gun armament. This was rec­og­nized by the au­thor­i­ties, and be­fore the in­va­sion, there was a big push to up­grade the Spit­fire’s armament to two 20mm can­nons and two .50-cal­iber ma­chine guns. A por­tion of a re­port ti­tled “Loose Minute,” de­scribes the ur­gency at the time:

In many re­spects, the Spit­fire IX was lightly armed when com­pared to the Typhoon (four 20mm can­non), P-47D Thun­der­bolt (eight 0.50-inch ma­chine guns), P-38J Light­ning (one 20mm can­non and four 0.50-inch ma­chine guns), and P-51D Mus­tang (six 0.50-inch ma­chine guns), all of which were em­ployed as dive-bombers and fighter-bombers. All would be equipped with bombs, and here again, the Spit­fire was found want­ing. All of the above fight­ers were ca­pa­ble of de­liv­er­ing 2,000 pounds of bombs, whereas the Spit­fire was only cleared to carry a 1,000-pound load in Septem­ber 1944. This was re­ally be­yond its ca­pa­bil­ity, with 60 per­cent of all ac­ci­dents when car­ry­ing a full load were caused by burst tires due to ex­ces­sive weight. Range was also an is­sue. With a sin­gle 500-pound bomb, the Spit­fire IX had a com­bat ra­dius of just 95 miles (even shorter with a full 1,000-pound load), whereas the Typhoon had a com­bat ra­dius of 250 miles with a 2,000-pound bomb load. This re­stricted the Spit­fires of the

2nd TAF to tar­gets that were in the im­me­di­ate bat­tle area, of­ten forc­ing them to at­tack tar­gets within range rather than by pri­or­ity.

One of the Spit­fire Wings heav­ily in­volved in both the air su­pe­ri­or­ity role and as a dive-bomber was those of No. 126 Wing Royal Cana­dian Air Force (RCAF) (No. 401, 411, and 412 Sq. RCAF). From D-Day to V-E Day, it was the most suc­cess­ful fighter wing on the con­ti­nent, with a to­tal of 333 enemy air­craft shot down. While its air-to-air record was spec­tac­u­lar, its dive-bomb­ing ac­tiv­i­ties were less so. For the pi­lots of No. 126 Wing, their dive-bomb­ing ac­tiv­i­ties started be­fore the D-Day land­ings. In April, the Spit­fires of No. 126 Wing be­gan their dive-bomb­ing at­tacks on the V-1 “Noball” sites in France. Flight Lt. Bill McRae of 401 Sq. takes up the story:

“In April of 1944, af­ter a short dive-bomb­ing course at Fair­wood Com­mon in Wales, where we used only small smoke bombs, 401 moved from RAF Big­gin Hill to RAF Tang­mere and be­gan di­ve­bomb­ing as part of our reg­u­lar du­ties. The Spit­fire had been used as a dive-bomber in the Mediter­ranean the­atre, but there I be­lieve only two wing­mounted 250 lb bombs were used. In Nor­mandy 401 Squadron car­ried only the belly-mounted 500-pounder. The tar­gets as­signed to us, mainly V-1 launch­ing sites and oc­ca­sion­ally small rail­way bridges, re­quired pin­point ac­cu­racy, some­thing al­most im­pos­si­ble to achieve with the tech­nique rec­om­mended for re­leas­ing belly-mounted bombs from a Spit­fire, i.e. to start the pull out be­fore re­leas­ing. Only once in my log do I men­tion the squadron hav­ing achieved a sig­nif­i­cant num­ber of hits.”

Op­er­a­tional Re­search stud­ies prior to D-Day

An­other “Loose Minute,” re­veals fig­ures re­lated to the num­ber of Spit­fires al­ready con­verted and ones com­ing off the pro­duc­tion lines:

clearly showed that bombs dropped from fight­ers in a dive were found to hit a viaduct 500 yards long and 8 yards wide just once in 82 at­tempts (the re­port doesn’t men­tion which type of fighter was used). And near misses did lit­tle dam­age.

Fight­ers Need Speed, Dive-Bombers Do Not

One of the Spit­fire’s great­est as­sets was its speed, but when in a dive, this was also a prob­lem. None of the Al­lied fight­ers that were used as di­ve­bombers were mod­i­fied to carry dive-brakes. Dive­brakes al­lowed a dive-bomber to main­tain a set speed dur­ing a dive, thus in­creas­ing bomb­ing ac­cu­racy. When a Spit­fire went into a dive, it gained speed rapidly with no way to slow it down. It also re­vealed a new and strange phe­nom­e­non. McRae de­scribes what was called “aileron up-float”:

“The first in­di­ca­tion of prob­lems came when our crews be­gan paint­ing a white and a yel­low line on the in­board chord of the ailerons. This, we were told, was to en­able us to watch for and take ac­tion in the event of ‘aileron up-float.’ This phe­nom­e­non had been known to the brass for at least a year, but it was news to us. Ap­par­ently at high speeds both ailerons would rise, or float, and if al­lowed to con­tinue could the­o­ret­i­cally reach the point where they would break off. When first dis­cov­ered on the Mk V, a sug­gested so­lu­tion was to droop both ailerons 5/8" at rest, so they could rise to neu­tral at high speed! In our case we were told to mon­i­tor the ailerons as the speed in­creased; if the white line ap­peared you were ap­proach­ing the crit­i­cal point, if the yel­low line showed you were to slow down! At the same time we were sup­posed to keep the air­speed below the Vne [ve­loc­ity— never ex­ceed]. Ob­vi­ously we were far too busy try­ing to keep the tar­get in sight, with red and white balls (AAA) [an­ti­air­craft ar­tillery] go­ing past us in the op­po­site di­rec­tion, to be check­ing the ailerons and the air­speed while in the dive, so both of these lim­it­ing fac­tors were sim­ply ig­nored. Reach­ing an in­di­cated AS [air speed] of 500 mph was not un­com­mon.”

Oper­a­tionally Un­fit: Pi­lots and Plane

While the RAF had fully em­braced the di­ve­bomb­ing tech­nique, it did noth­ing to mod­ify or equip both the Spit­fire and Typhoon for the role. No proper dive-bomb­ing sight was used, the bomb racks fit­ted to the air­craft were de­signed for level-bomb­ing, and the bombs them­selves were de­signed to be dropped from a lum­ber­ing Lan­caster fly­ing hor­i­zon­tally! And when the Spit­fire used the cen­ter­line-mounted 500-pound bomb, the pi­lot was forced to pull up through the tar­get be­fore re­leas­ing his bomb, thus de­grad­ing his ac­cu­racy. If he didn’t, the bomb wouldn’t clear the pro­pel­ler arch. When a Spit­fire was in a dive, it gained speed rapidly and of­ten ex­ceeded 450mph. This meant the re­lease point was above 4,000 feet. McRae de­scribes the phys­i­cally tax­ing pull-up ma­neu­ver and how it some­times proved deadly:

“On my first dive-bomb­ing show I went through the pro­ce­dure, pulled out with great difficulty, blacked out, to re­cover back up about where I started.

“I be­lieve the train­ing we had with small smoke bombs was in­ad­e­quate, es­pe­cially since we were not told what to ex­pect when deal­ing with the real thing. Con­se­quently we each had our own idea how to go about it. Ini­tially I trimmed out for the dive then tried to trim out while pulling out of the dive. It usu­ally took both hands on the stick, pulling with all my strength to get out of the dive. A day later I watched as an­other of our pi­lots ap­peared to be pulling out, then the dive steep­ened, past the ver­ti­cal, and he plowed right into the ground.”

Flak and small-arms fire also took a heavy toll. The Spit­fire’s liq­uid-cooled en­gine was ex­tremely vul­ner­a­ble to light flak. A sin­gle bul­let in the oil, gly­col tank, or ra­di­a­tor would of­ten spell the end, and the num­bers speak for them­selves. From D-Day to V-E Day, No. 126 Wing RCAF lost

131 Spit­fires and 98 pi­lots killed or cap­tured, all mostly due to flak.

Not Enough Bombs and Even Less Ac­cu­racy

The free-fall bombs of 1943–45 were also highly in­ac­cu­rate. Even the fa­bled “tank-bust­ing” Typhoon shared the same fate. In a re­port dated June 10, 1944, the Op­er­a­tional Re­search Sec­tion

of the Al­lied Ex­pe­di­tionary Force pub­lished a study about the ef­fec­tive­ness of fighter-bombers (Spit­fires and Typhoons). It be­came clear that the bomb-tot­ing Typhoons were nei­ther more or less ac­cu­rate than the Spit­fires. The only dif­fer­ence was the Typhoon was ca­pa­ble of car­ry­ing two 500-pound bombs to the Spit­fire’s one, mak­ing it twice as pow­er­ful (later, Spit­fires would carry one 500- and two 250-pound bombs). The re­sults, how­ever, were dis­ap­point­ing. Against such tar­gets as bridges, it was nec­es­sary to fly 90 to 180 Spit­fire bomb­ing sor­ties or 45 to 90 with Typhoons be­fore sub­stan­tial dam­age was in­flicted (the Typhoons’ abil­ity to carry two bombs de­creased the num­ber of sor­ties). It was also proven that when tar­gets were de­fended by flak and small-arms fire, ac­cu­racy de­creased even more.

To be fair to the Spit­fire, all the Al­lied fight­er­bombers suf­fered from the same dif­fi­cul­ties when it came to us­ing dive-bomb­ing tech­niques. Against fixed po­si­tions, fighter air­craft used as dive-bombers were largely in­ef­fec­tive, but when Ger­man forces were de­feated and in head­long re­treat, tac­ti­cal air power proved dev­as­tat­ing. Dur­ing Falaise and the Rhine cross­ings, traf­fic con­ges­tion pro­vided a tar­get-rich en­vi­ron­ment. Air at­tacks caused con­sid­er­able dam­age. Add the panic and con­fu­sion caused by the re­lent­less at­tacks and the re­sults were com­pletely de­mor­al­iz­ing for Ger­man ground forces. When the num­bers are bro­ken down, the 2nd TAF ded­i­cated only one-third of its sor­ties in di­rect sup­port of the ground troops. The other two-thirds were ded­i­cated to other mis­sions such as air su­pe­ri­or­ity, cut­ting French and Ger­man rail com­mu­ni­ca­tions, and at­tack­ing other tar­gets in Ger­many. These in­ter­dic­tion mis­sions were ar­guably the most ef­fec­tive con­tri­bu­tions made by the 2nd TAF dur­ing the war in western Europe.

As much as the RAF em­braced the con­cept of tac­ti­cal air power and the dive-bomb­ing tech­nique, it never se­ri­ously con­sid­ered ac­quir­ing a true dive-bomber. The Spit­fire was a failed at­tempt to make an in­ter­cep­tor into a dive-bomber. It was in­ac­cu­rate and too del­i­cate for the job. When the 2nd TAF was formed, the ob­vi­ous source of air­craft came from RAF Fighter Com­mand, which was over­whelm­ingly equipped with Spit­fires. While the Typhoon did gain a rep­u­ta­tion as an ef­fec­tive ground-at­tack air­craft, it was just as in­ac­cu­rate as the Spit­fire. One of the ob­vi­ous choices for a suit­able air­craft would have been the North Amer­i­can A-36 dive-bomber. Proven in Italy, it was over­looked by the RAF and was even­tu­ally re­placed by the P-47 Thun­der­bolt in 1944. One can only spec­u­late as to how ef­fec­tive two or three wings of A-36s would have been dur­ing the long ground cam­paign into Ger­many in 1944–45.

The Fi­nal Word

For McRae and the pi­lots of No. 126 Wing RCAF, it had been long slog. From D-Day to V-E Day, they dropped 4,426 500-pound and 3,883 250-pound bombs. They would go on to claim 4,468 ve­hi­cles de­stroyed or dam­aged; 493 lo­co­mo­tives blown up or dis­abled; 1,569 rail trucks in flames or holed; and 426 rail cuts.

Those are im­pres­sive num­bers. But the last word on the Spit­fire as a dive-bomber should go to McRae:

“In my opin­ion our ef­forts at dive-bomb­ing were al­most a com­plete fail­ure; we were un­able to achieve the pre­cise bomb­ing that our small tar­gets called for. Had we been given area tar­gets, such as mar­shalling yards or troop con­cen­tra­tions, we could have made a bet­ter con­tri­bu­tion.”

Spe­cial thanks to the late Bill McRae and Vin­tage Wings of Canada for the use of ma­te­rial for this ar­ti­cle.

The Mk V Spit­fire was a su­perb fighter but not good in the role of dive-bomber. (Photo by John Dibbs/ planepic­ture.com) The Mk III MC 500-pound bomb was the prin­ci­pal air-to-ground weapon car­ried by the Spit­fire of the RAF 2nd Tac­ti­cal Air Force in 1943–45. (Photo via Don­ald Ni­jboer)

The cock­pit of a Mk Vc Spit­fire. Note how the stick piv­ots in the mid­dle, rather than the bot­tom, of the stick. (Photo by John Dibbs/planepic­ture.com) The Phantom was pre-glass cock­pit and re­lied on steam gauges and the pi­lot to do its job. There were no com­put­ers to help the pi­lot. (Photo by Ted Carl­son)

A wing rider guides a No. 412 Squadron Mk IX out with a full load: 1,000 pounds of bombs (one 500- and two 250-pound bombs). The wing-mounted 250-pound bombs were of ques­tion­able tac­ti­cal value due to their low ex­plo­sive weight. (Photo cour­tesy of Don­ald Ni­jboer)

No. 401 Squadron Spit­fires armed with 500-pound bombs. Un­for­tu­nately, the 500-pound British bomb’s fuses and tail as­sem­blies were de­signed to be dropped hor­i­zon­tally, and the bomb was never in­tended to be de­liv­ered in a near-ver­ti­cal dive. So the pi­lot be­gan the pull­out be­fore re­leas­ing the bomb to en­sure clear­ing the pro­pel­ler, thus ru­in­ing bomb­ing ac­cu­racy. (Photo cour­tesy of Don­ald Ni­jboer)

A No. 442 Squadron Spit­fire Mk IX armed with a sin­gle 500-pound bomb. The Spit­fire’s light weight and short range lim­ited its bomb load—the Hawker Typhoon could haul 2,000 pounds of bombs on a con­sis­tent ba­sis, while the Spit­fire could carry only half that amount. (Photo cour­tesy of Don­ald Ni­jboer)

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