In the spring of 1935, Wimmer accompanied the Reichs Minister for Aviation, Generaloberst Hermann Göring, to Dessau for an inspection trip. In a vast hangar, Göring was shown a mock-up of the Ju 89. Aghast, he turned to Wimmer and asked ‘What on earth is that?’ Wimmer replied that it was the Ural Bomber, assuming the Minister had been previously advised. But an apparently angered Göring proclaimed, ‘Any major project such as this can only be decided by me personally.’2 Nevertheless, by May 1935, the development of such a heavy bomber had become the top priority of the Luftwaffe, and by late November 1935, its development programme included two new prototypes, the Dornier Do 19 and the Junkers Ju 89. But less than two months later, on 6 January 1936, three prototype Ju 89s were listed, with a fourth assigned as a transport for DLH, with a target date for a pre-production series of March 1938.3
Junkers subsequently produced one prototype of its big, all-metal, four-engined Ju 89 Grossverkehrsflugzeug (large transport) by 1936. Structurally similar to the Ju 86 and designed by Junkers chief designer, Diplom-Ingenieur Ernst Zindel, the unarmed Ju 89 V1, powered by four 1,075 hp Jumo 211A 12-cylinder liquid-cooled engines, made its first flight two months after the competing Dornier Do 19 on 11 April 1937 with company test pilot Peter Hesselbach at the controls. Similar in size to the British Short Stirling bomber, the aircraft had a monocoque fuselage and boasted a wingspan of 35.02 m and a wing area of 184 m2. It weighed 17,000 kg empty and had a take-off weight of around 23,000 kg. Further tests showed that the aircraft had a maximum speed of 390 km/h, but the installation of armament, planned as a 7.9 mm MG 15 machine gun in the nose and a 20 mm MG FF cannon in a dorsal and ventral turret, would have reduced such a performance considerably. The V1 was followed in July 1937 by the V2, fitted with 960 hp DB 600A engines. The aircraft could reach 390 km/h at maximum speed and could carry a bombload of 1600 kg, slightly heavier than the Dornier, over a marginally greater range, together with a crew of nine, including five gunners operating a similar armament to that carried by the Do 19. But both aircraft types were underpowered for their size and weight, and comparatively, neither could match the performance of the new American B-17 Flying Fortress.
Some initial, sub-assembly work had commenced on a third prototype, the V3, which was to have carried mock-ups of the two fuselage turrets, when the entire development programme was scrapped on 29 April 1937. One catalyst for this had been Wever’s death in an air crash in June 1936, after which Göring had reversed the Ural Bomber building programme in favour of the construction of smaller, faster twin-engined aircraft, such as the He 111 and the planned Ju 88. Apparently, the commander of the Luftwaffe had been swayed to act when he was advised of the heavy fuel consumption of the Do 19 and Ju 89 and that three twin-engined aircraft could be built for every two four-engined machines. Furthermore, engines of a sufficient power needed to optimize the performance of such aircraft were still lacking.
The loss of the Luftwaffe was to be Lufthansa’s gain. The airline had already shown some interest in the Ju 89 and as such, Junkers sought permission from the RLM to assign the major components of the V3, namely the wings and tail assembly, to the production of a new, private-venture, wide-bodied, commercial aircraft for DLH. The RLM agreed to Junkers’ request on the condition that new engines would be fitted to any new machines. The fuselage would be a completely new design.
The emerging aircraft was to be the Junkers Ju 90.
‘DER GROSSE DESSAUER’
The four-engined, all-metal, low-wing Ju 90 was a design that Ernst Zindel had first created in April 1936, before the inaugural flight of the Ju 89 V1 had even taken place. Zindel envisaged a large four-engined aircraft to be termed as a Transozeanflugzeug (pan-oceanic aircraft) or Schweretransport (heavy transport).4 Certainly, and in comparative terms, at the time of its release, the first prototype of the Ju 90 was the largest aircraft in Germany; its wingspan of 35.27 m was greater than that of the Do 19, and at 26.45 m it was a metre longer than that aircraft.
Construction of the aircraft took place at the Junkers works at Dessau where the wings, undercarriage and tail unit intended for the Ju 89 V3 were mated to the more streamlined fuselage of the Ju 90, although the aircraft did retain the Ju 89’s rectangular cross-section and rounded top. Aside from the Junkers double-wing type control surfaces, which had a corrugated covering, the rest of the aircraft was formed of smooth, flush-riveted Duralumin. The wings were built around five tubular girder spars covered with a smooth stressed skin. The leading edge was quite markedly swept, the trailing edge almost straight.
Initially, the first prototype, the Ju 90 V1, would be powered by the 960 hp DB 600 engines intended for the Ju 89 V3, although ultimately, it was intended to fit the type with 1,550 hp BMW 139 radials, which were then undergoing development.
For further design work, Zindel handed the Ju 90 over to Diplom-Ingenieur Heinz Kraft, who had worked in the Junkers construction office since 1935, having joined the firm from Rohrbach.5 Kraft would oversee the design of the Ju 90 and Ju 290 from the firm’s design office in Prague.
The first prototype of the Junkers Ju 90, the V1 Wk-Nr 4913 D-AALU, made its inaugural flight piloted by Hesselbach on 28 August 1937. However, after just a few months’ trials, D-AALU, named Der Grosse Dessauer after the Junkers plant at Dessau, broke up in flight and crashed just north-east of Libbesdorf, a village near the factory, after conducting flutter tests on 7 February 1938. Debris from the rudder, doors and engines were scattered around the village.6
The V2, Wk-Nr 4914 D-AIVI Preussen, first took to the skies on 2 December 1937, powered by four 830 hp BMW 132H radials. Six months later, the aircraft was being used for tests by DLH.
It was, undeniably, an impressive aircraft, elegant for its size. Passengers were accommodated four-abreast in facing rows on either side of a central aisle, in a roomy cabin measuring 2.83 m across internally, which was augmented by two toilets, a cloakroom and a mail compartment aft, while a food storage area, baggage hold and another cloakroom were located forward. The passenger seats could be converted into berths for night travel. Further baggage holds were located between the two wing spars and at the extreme aft of the fuselage.
The aircraft were powered variously by four 830 hp BMW 132H radials (as in the V2 and V3), 1,340 hp Jumo 211 Fs (the V4), 1,200 hp Pratt & Whitney SC3-G Twin Wasps (Wk-Nr 0002 and 0004) or 1,560 hp BMW 801As (on the V7 and V8).
From July 1938, two Ju 90s, starting with the V3 Wk-Nr 4915 D-AURE Bayern, were deployed on a trial basis on DLH’s Berlin–Vienna route, but just four months later, on 21 November 1938, while undergoing tropical flight tests for the airline, the V2 crashed at Bathurst in The Gambia, as a result of engine failure, killing 12 of the 15 people on board.
Fortunately, however, despite this inauspicious start to testing, a short run of ten Ju 90 A-1 (Z-2) production machines was planned, with DLH placing an order for eight. Interest also came from South African Airways for the remaining two (as the Ju 90 Z-3 with Twin Wasp engines), but this did not progress, and the outbreak of World War II prevented further civil use of the type.
Despite the Ju 90’s deployment as a civil transport, as early as March 1937, there were those in the Technisches Amt of the RLM that believed their aircraft should be used only in a limited military role.7 Yet, the Ju 90 prototypes saw both civil and military service, with the V3 used briefly as a transport by 4./KGr.z.b.V.107 during the Norwegian campaign in April 1940, after which it was returned to DLH. Likewise, in 1943, the Ju 90 V4 Wk-Nr 4916 D-ADLH Schwabenland served with the viermotorige-Transportstaffel, a specialist four-engined transport unit which operated under the direct control of the Luftwaffe High Command and which would eventually count several Ju 90A-1s on its strength. The V5 Wk-Nr 4917 D-ANBS, which first flew on 5 December 1939 and was the first aircraft to be fitted with new, oval tail fins, and V6 Wk-Nr 4918 D-AOKD were built as military prototypes. The rectangular windows of the earlier prototypes were replaced by round, ‘porthole’-style windows. The latter aircraft was fi
tted with the innovative Transporterklappe, known more usually as the ‘Trapoklappe’, a hydraulically operated ventral loading ramp which would enable military vehicles and guns to be driven directly into the fuselage, as well as allowing the dropping of large quantities of supplies by parachute. When lowered, the Trapoklappe raised the angle of the rear fuselage to a level position, allowing vehicles sufficient clearance to embark, and when closed, the ramp was pneumatically sealed. One of the ramp’s most practical features was that it had access steps faired centrally along its length with treaded edges to assist vehicles with adhesion during loading and unloading.
The Ju 90 V7 Wk-Nr 4919 D-APFH featured a considerably modifed, narrower, wing design, with a straight inner section leading edge, while the fuselage was lengthened by 1.98 m immediately aft of the rear spar attachment point, increasing overall length from 26.45 m to 28.5 m. The span of the new wing was 42 m, compared with preceding aircraft, which had spans of 35.27 m. The extended fuselage eliminated a yawing problem, as did the introduction of a tail assembly with horizontal stabilizers with marked dihedral. The V8 Wk-Nr 4920 D-AQJA also had the longer fuselage and was fitted with defensive armament, introducing a small gondola beneath the port side of the fuselage nose which housed two 20 mm MG 151 cannon, as well as a rearward-firing 13 mm MG 131 machine gun at the extreme aft point of the aircraft.
Importantly, however, in 1940 it was decided to exploit the design of the Ju 90 further, in order to create a large military aircraft able to undertake long-range transport and reconnaissance operations. But it was not until 11 February 1941 that the Technisches Amt instructed provisionally that the Ju 90 V11 Wk-Nr 900011 D-AFHG Oldenburg was to be assigned for this purpose, although this was not fully confirmed until October of that year. Given an increased span of 42 m, new, more angular and taller tail fins and rudders, and a return to rectangular fuselage windows, the aircraft was also a little longer than the Ju 90, measuring 28.68 m in length.
Junkers also fitted the aircraft with the Trapoklappe. Powered by four 1,560 hp BMW 801A engines, it emerged as the new Ju 290 V1 Wk-Nr 29000001 BD+TX.
‘A GIANT PIECE OF HARDWARE’
The Ju 290 V1 commenced flight-testing at Dessau on 16 July 1942 with Junkers test pilot Flugkapitän Hans-Joachim Pancherz at the controls along with flight engineer, Diplom-Ingenieur Rolf Geyling.
Like the Ju 90, it was one of the largest land aircraft in the German inventory (the Blohm & Voss BV 222 flying boat was larger), its fuselage marginally longer than the Messerschmitt Me 323 six-engined transport and its span almost 10 m greater than the four-engined Focke-Wulf Fw 200 Condor. It had a very roomy cockpit and a cavernous freight area, and although a ventral gondola was fitted, the forward dorsal turret was omitted and the aircraft carried no defensive armament. Internally, the copious, metal-walled stowage area measured 16.3 m in length and was 2.75 m wide and 2 m high.
Diplom-Ingenieur Kraft maintained overall control of the development programme, and within three months of the V1 flying, the Ju 290 V3 Wk-Nr 290110152 SB+QB was rolled out, Pancherz piloting it on its inaugural flight on 16 October; the V2 Wk-Nr 290110151 CE+YZ followed on 2 December. This latter aircraft had been converted from the Ju 90 V13, which had been slated for civil use by DLH; indeed, as late as 16 September 1942, German production plans still showed the aircraft as a ‘model for DLH use’.8
Meanwhile, the V1 concluded its flight-testing without any major problems on 22 November, and shortly thereafter the aircraft was flown to Lecce in southern Italy by Junkers works pilots Flugkapitäne Eduard Dautzenberg and Walter Hänig, along with Geyling, for operational trials in the Mediterranean environment.9 This was most probably in timely recognition of the fact that large-capacity transport was becoming an urgent requirement in the North African theatre.
Although the prototypes were manufactured at Dessau, Junkers decided that ensuing series production would be transferred to its Bernburg plant, where assembly facilities had been steadily developed.10 Meanwhile, the V2 and V3 served to become the first machines in the new A-1 transporter series, powered by 1,600 hp BMW 801L radial engines.
Within the first three months of 1943 four more Ju 290A-1s were produced, representing the entire sub-series, the first machine being built from the V4, the remaining three as newly built A-1s. Again all the airframes (with the exception of one, which was assigned to destruction testing at the Letov factory at Letnany in occupied Czechoslovakia) were test-flown without any major problems by Pancherz. These aircraft were assigned, officially at least, a crew of eight and were fitted with an HDL (Hydraulische Drehringlafette – hydraulically operated gun mount) 151 gun turret (15 mm MG 151 cannon) in the B1 Stand (forward dorsal), a single MG 151 mounted into the ventral gondola C1 Stand (forward ventral) and C2 Stand (aft ventral), and a further MG 151 at the H Stand (tail). A single such weapon could also be installed on FDL (Ferngerichtete Drehringlafetten – remotely controlled mounts) on each side of the fuselage.
Aircrew found the Ju 290 a comfortable aircraft to fly; it offered a straightforward take-off, it was stable in the air, and the slotted ailerons needed only the lightest of control. Although there was little risk of stall, changes in power or speed required immediate trimming, which was managed by a three-axis electric trimmer, a slide on the control wheel and an override trimmer, which could be operated by the flight engineer. In the spacious cockpit, dual controls were available, with a console located between the pilot and co-pilot, but one weak point was the restricted view when on the ground.11 Flieger-Stabsingenieur Hans-Werner Lerche was a test pilot at the Erprobungsstelle Rechlin in April 1943; he described the Ju 290 as a ‘flying delicacy’:
My first flight in this precious ‘ship’ was in the Ju 290 CE+YZ [an A-1 from the second prototype]. Later, I flew the Ju 290s SB+QG [an A-2] and SB+QB. Although I had already flown the larger Messerschmitt Me 323, the giant powered cargo glider with six Gnome-Rhône engines, the Ju 290 was a ‘real’ aeroplane. And, considering its large size, it was exceptionally pleasant to fly.
I remember well a particularly interesting flight in a Ju 290 when we had to evaluate the FuG 101 precision radio altimeter. At long last there was a task that made a pilot’s heart beat faster! Just imagine: officially permitted low-level flying with such a huge ‘steamer’! It was simply fascinating. As it was impossible to do this over land, even over the largest fields, I flew the required measuring run over Lake Müritz. Of course, one had to be terribly careful because the pilot’s seat was fairly high up in the Ju 290 cockpit and it would not have been the first time that someone had tickled the waves with the propeller tips. But I really enjoyed this low-level flight.
Later on I also had the opportunity to ferry a newly completed Junkers Ju 290 from the factory at Dessau to Rechlin. It really was a giant piece of hardware with its 42 m span and enormous fuselage. On overland flights I could really enjoy the excellent view from the Ju 290 cockpit. Despite its size the aircraft was pleasant to fly, but on landing one always had to remember that the height of the pilot’s eye level on touching down was more than 6 m above the ground. The qualities and performance of the Ju 290 transport, reconnaissance and bomber variants exceeded those of the Focke-Wulf Fw 200 Condor quite considerably, especially as regards armament and maximum range – which, in the case of the Ju 290, was some 6000 km.12
The Ju 290 first saw operational service under some of the most demanding conditions imaginable – especially for a still largely untried aircraft. At the end of December 1942, along with a Staffel of Ju 90s and some Fw 200s from I. and IV./KG 40, the Ju 290 V1 and A-1s were assigned to take part in the attempt to keep the German 6.Armee – surrounded by Soviet forces amidst the frozen ruins of Stalingrad – supplied by air. The aircraft were allocated to the mixed-type heavy transport Gruppe, KGr.z.b.V.200, based at Berlin-Staaken under the command of Major Hans-Jürgen Willers, a very experienced pilot who had previously flown He 111s with KG 4, KG 54 and KG 40. The first two Ju 290s to depart for Russia were the V1 BD+TX and the A-1
Wk-Nr 290110152 SB+QB. Following an interim stop at Wiener-Neustadt, the V1 landed at Stalino on 28 December. It made its first run to Pitomnik airfield, inside the Stalingrad pocket, in dense fog and with a strong risk of icing, on 10 January. But the mission was without incident. For its part, Wk-Nr 0152 suffered engine problems and was forced to return to Dessau, from where it took off once again on 6 January, staging via Warsaw, Kiev and Poltava, reaching Stalino at 1023 hrs on the 12th.
However, as Flugkapitän Walter Hänig attempted to take off from Pitomnik on the return from his second supply flight in the early hours of 13 January, the Ju 290 V1 crashed. Hänig, along with his Junkers flight engineer, Flieger-Oberingenieur Robert Stiefel, and three of his Luftwaffe crew members, together with 40 of the 75 wounded Wehrmacht troops on board, were killed. It was a grim beginning for the Ju 290.
Despite their valuable load capacities, and the obvious advantages of the Trapoklappe loading system over the more makeshift capabilities of the Fw 200, the big aircraft proved an easy target for Soviet fighters. Wk-Nr 0152’s flight to the pocket on the 13th would be its only one. The aircraft was piloted by the very experienced Major Hugo Wiskandt, who had joined Junkers in 1925, but who served later as Staffelkapitän of 1./KGr.z.b.V.172. He was accompanied by Flugkapitän Hesselbach as co-pilot and navigator, and Diplom-Ingenieur Geyling. The aircraft took off from Stalino in refreshingly clear winter skies, en route for Pitomnik, accompanied by an Fw 200. But a short while into their flight the German aircraft were attacked by a formation of five Soviet fighters. The Ju 290A-1 received multiple hits, but was able to make it to Pitomnik, where an inspection revealed that the aircraft’s fuel feed system had been damaged. After some hasty and temporary repairs, the aircraft took off again to return to Stalino, but with a restricted load of only some ten badly wounded soldiers. At Stalino, a full count showed that the Junkers had been hit no fewer than 123 times. Under such circumstances, no further operations were considered possible, and so on 17 January, it undertook a 5½-hour direct flight back to Rangsdorf in Germany. From there it flew to Tempelhof for major repair work, and not long afterwards it would be assigned another, equally dangerous task.13
Shadow over the Atlantic Page 5
