A false start with the Fw 159
Fw 159 – Focke-wulf ’s first single-seat fighter
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.
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.
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.
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.
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.
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.