A false start with the Fw 159

Fw 159 – Focke-wulf ’s first sin­gle-seat fighter

Aviation Classics - - CONTENTS -

The Fw 56 Stösser was beat­ing its com­peti­tors to be­come Ger­many’s stan­dard ad­vanced fighter trainer in Septem­ber 1934, lead­ing Kurt Tank to be­lieve it was the log­i­cal ba­sis for a new sin­gle-seat fighter. But he had reck­oned with­out the ge­nius of his for­mer boss, Willy Messer­schmitt.

Ger­many’s air forces had been com­pletely dis­banded by May 1920, un­der the pro­vi­sions of the Treaty of Ver­sailles, leav­ing the coun­try with­out any form of mil­i­tar y avi­a­tion. There were still thou­sands of pi­lots and avi­a­tion en­thu­si­asts, how­ever, who were un­will­ing to ac­cept this ban and mil­i­tary train­ing be­gan in se­cret at a num­ber of civil avi­a­tion schools dur­ing the early 1920s. When Adolf Hitler formed his first gov­ern­ment in Jan­uary 1933, one of his first acts was to begin the for­ma­tion of a new Luft­waffe – in di­rect con­tra­ven­tion of the re­stric­tions im­posed by the Al­lies. First World War fighter ace Her­mann Göring be­came the coun­try’s first post­war com­mis­sioner for avi­a­tion with Lufthansa direc­tor Erhard Milch as his deputy. All for­mer covert mil­i­tary avi­a­tion or­gan­i­sa­tions were merged into one body on May 15, 1933, and Milch, with the newly formed Re­ich­sluft­fahrt­min­is­terium (RLM), set about ob­tain­ing the air­craft that were needed to cre­ate a true Luft­waffe. Four re­quire­ments were drawn up – for a medium bomber, a light bomber, a two-seat heavy fighter and a sin­gle-seat fighter. Ger­many’s bur­geon­ing avi­a­tion in­dus­try was then in­vited to begin sub­mit­ting de­signs. Ger­many had ac­tu­ally be­gun the pro­duc­tion of sin­gle-seat fighter air­craft such as the Arado Ar 64 and 65 in se­cret in 1930 but th­ese were an­ti­quated de­signs and a mod­ern fighter air­craft was needed for the new air force. The RLM stip­u­lated that the suc­cess­ful de­sign should be able to main­tain a top speed of 400kph (250mph) at 6000m (19,690ft) for 20 min­utes and have an en­durance greater than 90 min­utes over­all. The 6000m had to be reached within 17 min­utes and the air­craft ser­vice ceil­ing had to be 10,000m (32,800ft) – a con­sid­er­able chal­lenge given the tech­nol­ogy avail­able in 1933. Ar­ma­ment was to be at least two 7.92mm ma­chine guns with 1000 rounds apiece or a sin­gle 20mm can­non with 200 rounds. Wing load­ing needed to be lower than 100kg per square me­tre. The en­gine to be used was the new Junkers Jumo 210, which was then still be­ing bench-tested. Junkers’ liq­uid-cooled in­verted V12 de­sign had three valves per cylin­der, a su­per­charger as stan­dard, and a cast cylin­der block. It was pre­dicted that it would pro­duce 700hp but in prac­tice out­put was more like 600hp. How­ever, a pro­viso had been added to the re­quire­ment that the Jumo 210 should be in­ter­change­able with the more pow­er­ful Daim­ler-benz DB 600 that was also un­der devel­op­ment.

Her­mann Göring sent let­ters out to Arado, Heinkel and Bay­erische Flugzeug­w­erke in Oc­to­ber 1933 ask­ing that work be com­menced on a ‘high speed courier air­craft’ to get de­sign ef­forts un­der way, while a for­mal in­vi­ta­tion for fighter de­signs was sent out in May 1934. Focke-wulf was not ini­tially con­sid­ered for the con­test but the suc­cess of the Fw 56 Stösser per­suaded RLM of­fi­cials that the Bre­men com­pany should also be asked to sub­mit a de­sign. Focke-wulf’s con­tract ar­rived in Septem­ber 1934 – al­most a year af­ter the oth­ers had be­gun devel­op­ment – with a re­quire­ment that three pro­to­types should be ready for testing early the fol­low­ing year. This tight timescale gave Kurt Tank and his team lit­tle room for ma­noeu­vre but the Fw 56 had al­ready proven it­self so there seemed no rea­son to start again from scratch. Ef­forts were con­cen­trated on up­grad­ing the trainer and mak­ing aero­dy­namic im­prove­ments to in­crease its per­for­mance. The re­sult was the Fw 159. De­tailed de­sign work was car­ried out by Ru­dolf Blaser and new fea­tures in­cluded an en­closed cock­pit with a slid­ing hood, an en­tirely new tail with a tail­wheel rather than a skid and two ma­chine guns mounted on the nose above the Jumo 210. The Fw 56’s ‘para­sol’ wing was re­shaped and fit­ted with flaps. A novel fea­ture of the new de­sign was a fuel tank which, po­si­tioned ahead of and be­low the pi­lot, could be jet­ti­soned in an emer­gency. Then there was the re­tractable un­der­car­riage. Un­able to fold into the wing, it folded up onto it­self and was then re­tracted through aper­tures in the fuse­lage that were not much larger than the wheels them­selves. Small doors then closed over the open­ings to leave the fuse­lage smoothly stream­lined. The Fw 159 V1 first flew in late spring 1935 with com­pany test pi­lot Wolf­gang Stein at the con­trols. The un­der­car­riage was re­tracted suc­cess­fully af­ter take­off but 30 min­utes of fly­ing later, although the oleo legs would ex­tend for land­ing, they would not lock into place cor­rectly. Stein tried to make them lock by putting the air­craft through a se­ries of ma­noeu­vres but noth­ing worked. The jet­ti­son­able fuel tank had not yet been fit­ted to the air­craft so Stein burned up as much fuel as pos­si­ble be­fore com­ing in to land with the gear un­locked. It col­lapsed on touch­down and the air­craft som­er­saulted twice be­fore com­ing to rest on its back. Although the aero­plane was wrecked, Stein walked away with just cuts and bruises. It was determined that the un­der­car­riage had failed be­cause Focke-wulf’s en­gi­neers had in­cor­rectly cal­cu­lated the amount of drag act­ing on the oleo legs – re­sult­ing in the hy­draulic cylin­der meant to lock the legs be­ing in­suf­fi­ciently pow­er­ful. The sec­ond Fw 159 pro­to­type, the V2, was there­fore fit­ted with a much more pow­er­ful cylin­der. Mean­while the first flight of the Bay­erische Flugzeug­w­erke en­try, the Bf 109, had taken place on May 29, 1935 – al­beit fit­ted with a Bri­tish Rolls-royce Kestrel VI be­cause designer Willy Messer­schmitt was un­able to ob­tain a Jumo 210. The Arado en­try, the Ar 80, had also flown with a Kestrel and the He 112, the Heinkel en­try, was de­layed. As the year wore on, fur­ther tests were car­ried out and a ready sup­ply of Jumo 210 en­gines be­came avail­able. The Heinkel He 112 first flew in Septem­ber with a Kestrel en­gine and then in Novem­ber with a Jumo. Luft­waffe ac­cep­tance tri­als of the four de­signs fi­nally com­menced in late 1935 at the cen­tral mil­i­tary avi­a­tion test and devel­op­ment fa­cil­ity at Rech­lin. Ernst Udet took a keen in­ter­est in the Fw 159 and flew it when­ever he was at Rech­lin on busi­ness. He was par­tic­u­larly fas­ci­nated by the un­usual un­der­car­riage re­trac­tion sys­tem, which was still prov­ing to be prob­lem­atic. Udet re­port­edly en­joyed teas­ing Tank about the way first one leg would par­tially re­tract, then the other would pull in, but then the first one would stick back out again, back and forth, un­til both were fi­nally nes­tled safely in­side the fuse­lage and the un­der­car­riage doors could close. As the ac­cep­tance tri­als con­tin­ued, it be­came ap­par­ent that the Fw 159 was up against some par­tic­u­larly stiff com­pe­ti­tion.

The least suc­cess­ful de­sign of the com­pe­ti­tion was that sub­mit­ted by Arado. Although the Ar 80 had a low mono­plane wing, it had a fixed un­der­car­riage which im­me­di­ately placed it at a dis­ad­van­tage com­pared to the oth­ers. The Ar 80’s orig­i­nal designer, Wal­ter Rethel, had in­tended it to have re­tractable gear but this could not be made to work cor­rectly and when Rethel left Arado to join Messer­schmitt at Bay­erische Flugzeug­w­erke, his re­place­ment Wal­ter Blume thought that a fixed un­der­car­riage would save weight. The ex­tra drag, how­ever, meant that the Ar 80’s per­for­mance was un­ex­cep­tional at best. Heinkel’s He 112 proved to be a much tougher op­po­nent for the Fw 159. De­signed by twin broth­ers Wal­ter and Siegfried Gün­ter, it was based on the world record break­ing He 70 fast mail car­rier aero­plane and drawn up with a BMW ra­dial en­gine in mind as Pro­jekt 1015. Per­for­mance was un­re­mark­able to begin with, un­til the broth­ers re­alised that a smaller, thin­ner wing would re­sult in a sig­nif­i­cant re­duc­tion in drag. With this prob­lem solved, the He 112 was quickly cho­sen as the front run­ner in the com­pe­ti­tion. Fi­nally, there was the Bf 109. Be­gin­ning as the rank out­sider, Messer­schmitt’s 109 quickly demon­strated that its light­weight de­signed gave it a level of per­for­mance sur­pass­ing any other de­sign in Ger­many. Hav­ing been ac­cepted by the Luft­waffe, the four de­signs were then moved to the se­cret testing sta­tion at Travemünde for com­par­a­tive tri­als. Within a month, the Arado team were told that their aero­plane had been re­jected. Dis­ap­point­ment was not long in com­ing for Tank ei­ther. When com­pared with the Heinkel and Messer­schmitt de­signs, the Fw 159 sim­ply could not com­pete. Its prob­lem­atic un­der­car­riage was a fa­tal flaw but its over­all lay­out also made it ap­pear un­gainly and dated against its com­peti­tors. Look­ing back, it must have been some con­so­la­tion to Focke-wulf that its de­sign was up against one of the finest pis­ton en­gine fighters ever pro­duced – the Bf 109.

FALKE FAIL­URE

Even though the Fw 159 had been re­jected, work on it con­tin­ued in the hope that it might yet meet an­other Luft­waffe re­quire­ment. In Septem­ber, plans were sub­mit­ted to the RLM for a light fighter des­ig­nated Fw 259, which was an Fw 159 fit­ted with a DB 601 en­gine. Th­ese came to noth­ing how­ever. In 1937, the third Fw 159 pro­to­type was reengined with a more pow­er­ful Jumo 210 G, en­abling it to fi­nally meet the orig­i­nal com­pe­ti­tion re­quire­ment of 250mph. The early pro­to­types had only man­aged 239mph. But again, this work went no fur­ther. It galled Tank that his com­pany’s de­signs for both the two-seat heavy fighter and sin­gle- seat fighter com­pe­ti­tions had been beaten by Messer­schmitt ma­chines – the Bf 110 hav­ing by now suc­ceeded where the Fw 57 had failed. He there­fore determined to press ahead with fighter devel­op­ment, de­spite there be­ing no RLM re­quire­ment for an­other de­sign at that time. The re­sult of this pro­gramme was the Fw 187 Falke (Fal­con), a sin­gle-seat twin-en­gine ma­chine which had a low wing and was de­signed for speed. Work on it be­gan al­most as soon as the Fw 159 had been re­jected and the chief of devel­op­ment at the RLM’S Tech­nis­ches Amt, Oberst Wol­fram Frei­herr von Richthofen, was so im­pressed with the idea that he gave Tank a con­tract for three pro­to­types. Once again, the de­tail work was handed to Ru­dolf Blaser and he fo­cused on try­ing to in­crease the type’s top speed through aero­dy­namic im­prove­ments and re­duced drag. The plan was to fit a pair of 960hp DB 600 en­gines but th­ese were not yet avail­able so they were sub­sti­tuted for two Jumo 210s. Af­ter the Fw 159’s is­sues the Fw 187’s un­der­car­riage was sim­plic­ity it­self – the main wheels re­tracted straight back­wards into the ca­pa­cious na­celles be­hind the en­gines. The tail­wheel was also re­tractable.

There were split flaps to make land­ing eas­ier and the fuse­lage was kept ex­tremely nar­row. Tank flew Fw 187 V1 for the first time in late sum­mer 1937 and the test pro­gramme was con­tin­ued by Hans San­der. He later de­scribed the ex­pe­ri­ence: “The Fw 187 was the first pro­to­type that I test flew af­ter join­ing Focke-wulf as a test pi­lot. It was re­ally quite a fast aero­plane, faster than the Bf 110 and the Heinkel He 112 with Jumo 210Ds. “On its first flights the Falke at­tained speeds of 525kph at low al­ti­tudes; that was 225kph faster than the Luft­waffe’s then­cur­rent front line fighters could reach. It was some 35kph to 40kph faster than the Bf 109 with the same en­gine and at the same altitude. “Fur­ther­more, it had a much higher range and load, mean­ing that I could have set a whole se­ries of records with the plane – some­thing which the higher ups didn’t want to see hap­pen. With its ar­ma­ment of four MG 17s and two MG FF can­nons in­stalled later, the plane was the air­craft our Luft­waffe later lacked when the war broke out. “For the pi­lots, it of­fered ex­cel­lent all­round visibility on take­off, land­ing and dur­ing flight – thanks to a large win­dow in the fuse­lage floor, it even of­fered good down­ward visibility. The rud­der forces were quite ac­cept­able with ad­e­quate sta­bil­ity, even if their ef­fec­tive­ness and re­spon­sive­ness was not up to the per­fec­tion achieved with the later Fw 190.” The Fw 187’s ex­cel­lent test re­sults were de­liv­ered to the RLM but it re­fused to sanc­tion any fur­ther devel­op­ment of the type due to its weight – it weighed as much as two Bf 109s – and the fact that with two en­gines it would re­quire twice as much main­te­nance. When Ernst Udet took over from von Richthofen as the Tech­nis­ches Amt’s chief of devel­op­ment, he was im­pressed by the Fw 187’s speed but was some­what less thrilled by what he re­garded as its lack of ma­noeu­vra­bil­ity. Nev­er­the­less, it was sug­gested that Tank could re­design the air­craft as a two-seat heavy fighter. Tank there­fore con­verted two of the pro­to­types, V3 and V4, by ex­tend­ing their fuse­lages. Sec­ond cock­pits were in­stalled and fuel tanks were moved from the wings to the fuse­lage, al­low­ing the Fw 187’s flaps to be ex­tended all the way along the wings. V3 was de­stroyed in a crash re­sult­ing from an en­gine fire in early 1938 and V1 was lost when its pi­lot Paul Bauer tried to pull a loop af­ter buzzing the air­field at low altitude. The air­craft lost too much speed and en­tered a flat spin at the apex of the loop, break­ing apart when it hit the ground sec­onds later. De­spite th­ese set­backs, the RLM is­sued a con­tract for two more two-seater pro­to­types – V5 and V6. The V6 fi­nally saw the in­stal­la­tion of the en­gines Tank had wanted all along, a pair of DB 600As gen­er­at­ing 1050hp each. Dur­ing tests Fw 187 V6 was able to reach a top speed of 635kph (394mph). The RLM gave Fock­eWulf a fur­ther con­tract for three pre­pro­duc­tion air­craft – Fw 187A-01 to Fw 187A-03 – but in the end the Fw 187 was dropped. The re­main­ing pro­to­types and pre­pro­duc­tion air­craft were formed up into the Bre­men In­dus­tri­eschutz-staffel and were flown against en­emy air­craft by Focke-wulf test pi­lots dur­ing air raids. Back in 1936, hav­ing failed with the Fw 159 and with the Fw 187’s fu­ture by no means cer­tain, Tank turned his at­ten­tion to Focke-wulf’s orig­i­nal area of ex­per­tise: air­liner pro­duc­tion. Know­ing that Dutch air­line KLM had be­gun to op­er­ate Amer­i­can Dou­glas DC-2S, he pro­posed a new four-en­gine de­sign to Lufthansa, the Fw 200 Con­dor. The air­craft his of­fice came up with stunned ev­ery­one who saw it and it made its first flight on July 27, 1937, just over a year af­ter he had pitched the idea. While work on the Fw 187 and the Fw 200 was on­go­ing, the RLM is­sued an­other spec­i­fi­ca­tion, this time for a short-range re­con­nais­sance aero­plane. With other firms such as Bay­erische Flugzeug­w­erke and Heinkel now busy work­ing on other types, Focke-wulf, Arado and the Ham­burger Flugzeug­bau were in­vited to sub­mit pro­pos­als. Focke-wulf’s twin-boom Fw 189 Uhu (Owl) was pro­nounced the win­ner and was al­ready fly­ing less than a year later. Mean­while, Focke-wulf’s dogged per­sis­tence in at­tempt­ing to pro­duce a high per­for­mance fighter air­craft and its abil­ity to turn de­signs around in record time had not gone un­no­ticed. Nor had its enor­mous and bur­geon­ing pro­duc­tion fa­cil­i­ties – which were rapidly be­ing ex­panded to cope with the de­mands of build­ing Fw 44s and Fw 56s. There was grow­ing con­cern within the RLM that the Bf 109, for all its ex­cel­lent qual­i­ties, might not be suf­fi­cient to deal with the grow­ing threat pre­sented by the likes of Su­per­ma­rine’s Spit­fire in Bri­tain. It was also con­sid­ered that most other coun­tries had one or more dif­fer­ent sin­gle-seat fighter de­signs op­er­at­ing in tan­dem and that Ger­many might do well to have its own ‘zweites eise im feuer’ or ‘sec­ond iron in the fire’. Con­se­quently, Tank was ap­proached by the RLM with an in­vi­ta­tion to sub­mit de­signs for an en­tirely new sin­gle-seat fighter. This was to be the Focke-wulf Fw 190.

Edi­tor’s col­lec­tion Edi­tor’s col­lec­tion

Reg­is­tered as D-IUPY, the Fw 159 V3 shows off its spindly un­der­car­riage. The sec­ond Focke-wulf Fw 159 in flight.the sin­gle-seat para­sol wing type was a hastily pre­pared devel­op­ment of the com­pany’s Fw 56 Stösser ad­vanced trainer.

Edi­tor’s col­lec­tion Edi­tor’s col­lec­tion Edi­tor’s col­lec­tion Edi­tor’s col­lec­tion

An­other view of the Fw 159 V3, with its en­gine ac­cess hatches open.v3 was the air­craft that went up against the Bf 109 V2, the He 112 V4 and the Ar 80 V3 in com­par­a­tive tri­als and lost. The Ar 80, Arado’s en­try for the sin­gle-seat fighter com­pe­ti­tion, was be­set with prob­lems from the out­set. It ended up sad­dled with a fixed un­der­car­riage af­ter its de­sign­ers fell out. A front view of the Ar 80 V3.the drag pro­duced by its un­der­car­riage badly af­fected its per­for­mance and it was the first air­craft elim­i­nated from the com­par­a­tive tri­als. The speed and ex­cel­lent hand­ing of the Heinkel He 112, once its wings had been re­designed, made it a tough op­po­nent for the Fw 159.

Edi­tor’s col­lec­tion Edi­tor’s col­lec­tion Edi­tor’s col­lec­tion Edi­tor’s col­lec­tion

An early He 112 in flight. Although it failed to win the com­pe­ti­tion to be­come the Luft­waffe’s new front line fighter, the He 112 was not a com­plete fail­ure. It was of­fered to cus­tomers around the world and was even­tu­ally bought by the Ja­panese, Hun­gar­i­ans and Ro­ma­ni­ans. The trio of pre­pro­duc­tion two-seater Fw 187s. When the RLM failed to is­sue a full pro­duc­tion con­tract for the type, the re­main­ing Falke air­craft were added to the Bre­men In­dus­tri­eschutz-staffel and flown in de­fence of Bre­men and the Focke-wulf fac­tory dur­ing air raids. The ex­cel­lent Bay­erische Flugzeug­w­erke, or Messer­schmitt af­ter 1938, Bf 109 eas­ily de­feated the Fw 159 – a galling ex­pe­ri­ence for Focke-wulf’s Kurt Tank. Pic­tured here is the Bf 109 V3, reg­is­tered as D-IOQY. For a short time the Fw 187 was one of the fastest air­craft in the world, even able to out­pace the Bf 109. Its slen­der fuse­lage and sim­ple re­li­able un­der­car­riage di­rectly ben­e­fited from Focke-wulf’s ex­pe­ri­ence with the Fw 159.This is the Fw 187 V2.

Edi­tor’s col­lec­tion

The Fw 187 V3 which was later de­stroyed in a crash fol­low­ing an en­gine fire. Kurt Tank’s per­sis­tence with the type helped to per­suade the RLM that Focke-wulf was the right choice to de­velop a front line fighter that could serve in par­al­lel to the Bf 109.

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