Junkers Ju 90
Encyclopedia
The Junkers
Ju 90 was a 40-seat, four-engine airliner
developed for and used by Deutsche Luft Hansa
shortly before World War II
. It was based on the rejected Ju 89
bomber
. During the war, the Luftwaffe
impressed them as military transports.
series descended directly from the Ju 89
, a contender in the Ural bomber
programme aimed at producing a long-range strategic bomber
. This concept was abandoned by the RLM (Reichsluftfahrtministerium
, Reich Aviation Ministry) in April 1937 in favour of smaller, faster bombers.
put a request for a long-distance commercial aircraft as early as 1933. When the Ju 89 program was abandoned, the third prototype
was partially completed and at the request of Luft Hansa, it was rebuilt as an airliner, retaining the wings and tail of the original design but incorporating a new, wider passenger-carrying fuselage
. The new design was designated the Ju 90.
The Junkers Ju 90 was a four-engine all-metal, low-wing aircraft fitted with twin end-plate vertical stabilizer
s. The wings were built around five tubular girder spar
s covered with a smooth stressed skin
. The leading edge
was quite markedly swept
, the trailing edge
almost straight. The Junkers "double wing", a full-span movable flap
/aileron
combination was fitted. The tail unit used the traditional Junkers corrugated skin, the only part of the aircraft to do so. The fins and rudder
s, the latter with prominent horn balances assemblies were placed at the end of the tailplane
; this latter carried the elevator
s separated by a gap, forming another double wing. These components were as used in the Ju 89.
The new fuselage was of oval cross section, covered by stressed smooth duralumin
skin. On the first four Ju 90As, there were five pairs of rectangular windows on each side, each double pair lighting a divided-off section of the cabin
containing eight seats in facing pairs on either side of a central aisle. The Ju 90B (from prototype Ju 90V5 to Ju 90V10 aircraft) adopted round fuselage portholes. The Ju 90V11 became the definitive Ju 290
prototype with smaller rectangular fuselage windows.
The Ju 90B series were visually distinctive because of their oval tail fins. Ju 90V-6 was withdrawn and rebuilt as the Ju 390V1
prototype. The Ju 90V9 was also withdrawn and rebuilt as the Ju 390V2, later redesignated in October 1944 as the Ju 390A1. Ju 90V10 was rebuilt as the Ju 390V3 bomber prototype, but was scrapped at the factory in June 1944. Junkers were paid compensation for seven Ju 390 under construction when Ju 390 orders were cancelled.
There were four or five divided fuselage sections, the latter holding the maximum of 40 passengers. There were toilet
s, a cloakroom and a mail store aft, and a baggage hold forward of the passenger space. The fuselage was generous by the standards of the time with an internal width of 2.83 m (9 ft 3½ in).
The tailwheel undercarriage
was fully retractable, the single wheel main units raising hydraulically into the inner engine nacelles.
The first prototype, the Ju 90V1 was powered by four Daimler-Benz DB 600
C liquid-cooled inverted V engine
s delivering 820 kW (1,100 hp) each. These were more powerful than both those of its Ju 89 predecessor and of production commercial Ju 90s. Named Der Grosse Dessauer, its maiden flight took place on 28 August 1937. Deutsche Luft Hansa carried out the long-distance testing. After eight months of flight tests, this prototype broke up on 6 February 1938 during over-speed tests.
A second prototype (V2) was delivered to Luft Hansa in May 1938
for testing. Like all the production commercial Ju 90s, this was powered by four BMW 132
radial engine
s delivering 620 kW (830 hp). The move to lower power was probably necessitated by the demands on Daimler Benz to produce engines for strategically important, front line aircraft. They named this aircraft Preussen. It crashed fatally during tropical flight tests on takeoff in November 1938 at Bathurst, Gambia, probably because of engine failure.
Despite these setbacks, Luft Hansa ordered eight of the production type A-1.
They also used the next two prototypes, starting with V3 Bayern which flew on the Berlin-Vienna route from July 1938. It is said that this aircraft flew a total of 62,572 km ( mi) in 1938. Only seven of the A-1s were delivered to Luft Hansa, the last in April 1940, one going directly to the Luftwaffe.
South African Airways
also ordered two A-1s with Pratt & Whitney Twin Wasp engines delivering 670 kW (900 hp). These were known by the alternative designation Z-3 to distinguish them from the BMW-powered Z-2. Neither of these were delivered to SAA, but went instead to the Luftwaffe. As the war progressed, the surviving six Luft Hansa airframes were also impressed in to Luftwaffe service,
though two were returned to Luft Hansa later. Four of these aircraft took part in the invasion of Norway
.
The fourth prototype V4 went into Luftwaffe service in July 941 fitted with 980 kW (1,320 hp) Jumo 211F/L engines.
In April 1939
, the RLM asked Junkers for a further development of the Ju 90 for military transport purposes. The Ju 90V5 and V6 were the prototypes of this military design. They got a new wing with a straight inner section leading edge, of greater span (19%) and area (11%). The landing gear was strengthened with twin main-wheels and the fins were more rounded, lacking the characteristic horn balance nick of the earlier models. The windows were replaced by 10 small portholes a side. The Ju 90 V5 flew first on 5 December 1939. A special feature of both the V5 and V6 was a boarding ramp in the floor of the fuselage for loading cars and larger cargo freight. This ramp, when lowered raised the fuselage to the horizontal flying position. Both aircraft were retrospectively fitted with the much more powerful 1,200 kW (1,600 hp) BMW 801MA radials.
The two last prototypes - the V7 and V8 - fed directly into the Ju 290 development programme. The former had a fuselage extension of 1.98 m (6 ft 6 in) and the addition of dihedral to the tailplane to solve a yaw instability. A reconnaissance prototype aerodynamically similar to the V7, the V8 was armed, however,with two 20 mm MG 151/20 cannon
s and up to nine 13 mm (.51 in) MG 131 machine gun
s in two dorsal, one ventral and one tail position.
Germany
Junkers
Junkers Flugzeug- und Motorenwerke AG , more commonly Junkers, was a major German aircraft manufacturer. It produced some of the world's most innovative and best-known airplanes over the course of its fifty-plus year history in Dessau, Germany. It was founded there in 1895 by Hugo Junkers,...
Ju 90 was a 40-seat, four-engine airliner
Airliner
An airliner is a large fixed-wing aircraft for transporting passengers and cargo. Such aircraft are operated by airlines. Although the definition of an airliner can vary from country to country, an airliner is typically defined as an aircraft intended for carrying multiple passengers in commercial...
developed for and used by Deutsche Luft Hansa
Deutsche Luft Hansa
Deutsche Luft Hansa A.G. was a German airline, serving as flag carrier of the country during the later years of the Weimar Republic and throughout the Third Reich.-1920s:Deutsche Luft Hansa was founded on 6 January 1926 in Berlin...
shortly before World War II
World War II
World War II, or the Second World War , was a global conflict lasting from 1939 to 1945, involving most of the world's nations—including all of the great powers—eventually forming two opposing military alliances: the Allies and the Axis...
. It was based on the rejected Ju 89
Junkers Ju 89
|-See also:-External links:*...
bomber
Bomber
A bomber is a military aircraft designed to attack ground and sea targets, by dropping bombs on them, or – in recent years – by launching cruise missiles at them.-Classifications of bombers:...
. During the war, the Luftwaffe
Luftwaffe
Luftwaffe is a generic German term for an air force. It is also the official name for two of the four historic German air forces, the Wehrmacht air arm founded in 1935 and disbanded in 1946; and the current Bundeswehr air arm founded in 1956....
impressed them as military transports.
Design and development
The Junkers Ju 90 airliner and transportCargo aircraft
A cargo aircraft is a fixed-wing aircraft designed or converted for the carriage of goods, rather than passengers. They are usually devoid of passenger amenities, and generally feature one or more large doors for the loading and unloading of cargo...
series descended directly from the Ju 89
Junkers Ju 89
|-See also:-External links:*...
, a contender in the Ural bomber
Ural bomber
The Ural bomber was a program to develop a long-range bomber for the Luftwaffe, created and led by General Walther Wever in the early 1930s. Wever died in an air crash in 1936 and the program ended almost immediately...
programme aimed at producing a long-range strategic bomber
Strategic bomber
A strategic bomber is a heavy bomber aircraft designed to drop large amounts of ordnance onto a distant target for the purposes of debilitating an enemy's capacity to wage war. Unlike tactical bombers, which are used in the battle zone to attack troops and military equipment, strategic bombers are...
. This concept was abandoned by the RLM (Reichsluftfahrtministerium
Reich Air Ministry
thumb|300px|The Ministry of Aviation, December 1938The Ministry of Aviation was a government department during the period of Nazi Germany...
, Reich Aviation Ministry) in April 1937 in favour of smaller, faster bombers.
Civil development
Deutsche Luft HansaDeutsche Luft Hansa
Deutsche Luft Hansa A.G. was a German airline, serving as flag carrier of the country during the later years of the Weimar Republic and throughout the Third Reich.-1920s:Deutsche Luft Hansa was founded on 6 January 1926 in Berlin...
put a request for a long-distance commercial aircraft as early as 1933. When the Ju 89 program was abandoned, the third prototype
Prototype
A prototype is an early sample or model built to test a concept or process or to act as a thing to be replicated or learned from.The word prototype derives from the Greek πρωτότυπον , "primitive form", neutral of πρωτότυπος , "original, primitive", from πρῶτος , "first" and τύπος ,...
was partially completed and at the request of Luft Hansa, it was rebuilt as an airliner, retaining the wings and tail of the original design but incorporating a new, wider passenger-carrying fuselage
Fuselage
The fuselage is an aircraft's main body section that holds crew and passengers or cargo. In single-engine aircraft it will usually contain an engine, although in some amphibious aircraft the single engine is mounted on a pylon attached to the fuselage which in turn is used as a floating hull...
. The new design was designated the Ju 90.
The Junkers Ju 90 was a four-engine all-metal, low-wing aircraft fitted with twin end-plate vertical stabilizer
Vertical stabilizer
The vertical stabilizers, vertical stabilisers, or fins, of aircraft, missiles or bombs are typically found on the aft end of the fuselage or body, and are intended to reduce aerodynamic side slip. It is analogical to a skeg on boats and ships.On aircraft, vertical stabilizers generally point upwards...
s. The wings were built around five tubular girder spar
Spar (aviation)
In a fixed-wing aircraft, the spar is often the main structural member of the wing, running spanwise at right angles to the fuselage. The spar carries flight loads and the weight of the wings whilst on the ground...
s covered with a smooth stressed skin
Stressed skin
In mechanical engineering, stressed skin is a type of rigid construction, intermediate between monocoque and a rigid frame with a non-loaded covering:...
. The leading edge
Leading edge
The leading edge is the part of the wing that first contacts the air; alternatively it is the foremost edge of an airfoil section. The first is an aerodynamic definition, the second a structural one....
was quite markedly swept
Swept wing
A swept wing is a wing planform favored for high subsonic jet speeds first investigated by Germany during the Second World War. Since the introduction of the MiG-15 and North American F-86 which demonstrated a decisive superiority over the slower first generation of straight-wing jet fighters...
, the trailing edge
Trailing edge
The trailing edge of an aerodynamic surface such as a wing is its rear edge, where the airflow separated by the leading edge rejoins. Essential control surfaces are attached here to redirect the air flow and exert a controlling force by changing its momentum...
almost straight. The Junkers "double wing", a full-span movable flap
Flap (aircraft)
Flaps are normally hinged surfaces mounted on the trailing edges of the wings of a fixed-wing aircraft to reduce the speed an aircraft can be safely flown at and to increase the angle of descent for landing without increasing air speed. They shorten takeoff and landing distances as well as...
/aileron
Aileron
Ailerons are hinged flight control surfaces attached to the trailing edge of the wing of a fixed-wing aircraft. The ailerons are used to control the aircraft in roll, which results in a change in heading due to the tilting of the lift vector...
combination was fitted. The tail unit used the traditional Junkers corrugated skin, the only part of the aircraft to do so. The fins and rudder
Rudder
A rudder is a device used to steer a ship, boat, submarine, hovercraft, aircraft or other conveyance that moves through a medium . On an aircraft the rudder is used primarily to counter adverse yaw and p-factor and is not the primary control used to turn the airplane...
s, the latter with prominent horn balances assemblies were placed at the end of the tailplane
Tailplane
A tailplane, also known as horizontal stabilizer , is a small lifting surface located on the tail behind the main lifting surfaces of a fixed-wing aircraft as well as other non-fixed wing aircraft such as helicopters and gyroplanes...
; this latter carried the elevator
Elevator (aircraft)
Elevators are flight control surfaces, usually at the rear of an aircraft, which control the aircraft's orientation by changing the pitch of the aircraft, and so also the angle of attack of the wing. In simplified terms, they make the aircraft nose-up or nose-down...
s separated by a gap, forming another double wing. These components were as used in the Ju 89.
The new fuselage was of oval cross section, covered by stressed smooth duralumin
Duralumin
Duralumin is the trade name of one of the earliest types of age-hardenable aluminium alloys. The main alloying constituents are copper, manganese, and magnesium. A commonly used modern equivalent of this alloy type is AA2024, which contains 4.4% copper, 1.5% magnesium, 0.6% manganese and 93.5%...
skin. On the first four Ju 90As, there were five pairs of rectangular windows on each side, each double pair lighting a divided-off section of the cabin
Aircraft cabin
An aircraft cabin is the section of an aircraft in which passengers travel. At cruising altitudes of modern commercial aircraft the surrounding atmosphere is too thin to breathe without an oxygen mask, so cabins are pressurized at a higher pressure than ambient pressure at altitude.In commercial...
containing eight seats in facing pairs on either side of a central aisle. The Ju 90B (from prototype Ju 90V5 to Ju 90V10 aircraft) adopted round fuselage portholes. The Ju 90V11 became the definitive Ju 290
Junkers Ju 290
The Junkers Ju 290 was a long-range transport, maritime patrol aircraft and heavy bomber used by the Luftwaffe late in World War II.-Design and development:...
prototype with smaller rectangular fuselage windows.
The Ju 90B series were visually distinctive because of their oval tail fins. Ju 90V-6 was withdrawn and rebuilt as the Ju 390V1
Junkers Ju 390
The Junkers Ju 390 was a German aircraft intended to be used as a heavy transport, maritime patrol aircraft, and long-range bomber, a long-range derivative of the Ju 290...
prototype. The Ju 90V9 was also withdrawn and rebuilt as the Ju 390V2, later redesignated in October 1944 as the Ju 390A1. Ju 90V10 was rebuilt as the Ju 390V3 bomber prototype, but was scrapped at the factory in June 1944. Junkers were paid compensation for seven Ju 390 under construction when Ju 390 orders were cancelled.
There were four or five divided fuselage sections, the latter holding the maximum of 40 passengers. There were toilet
Toilet
A toilet is a sanitation fixture used primarily for the disposal of human excrement, often found in a small room referred to as a toilet/bathroom/lavatory...
s, a cloakroom and a mail store aft, and a baggage hold forward of the passenger space. The fuselage was generous by the standards of the time with an internal width of 2.83 m (9 ft 3½ in).
The tailwheel undercarriage
Conventional landing gear
thumb|The [[Piper PA-18|Piper Super Cub]] is a popular taildragger aircraft.thumb|right|A [[Cessna 150]] converted to taildragger configuration by installation of an after-market modification kit....
was fully retractable, the single wheel main units raising hydraulically into the inner engine nacelles.
The first prototype, the Ju 90V1 was powered by four Daimler-Benz DB 600
Daimler-Benz DB 600
|-See also:-References:* Green, William. The Augsburg Eagle: A Documentary History - Messerschmitt Bf 109. London: Macdonald and Jane's Publishing Group Ltd. 1980. ISBN 0-7106-0005-4...
C liquid-cooled inverted V engine
V engine
A V engine, or Vee engine is a common configuration for an internal combustion engine. The cylinders and pistons are aligned, in two separate planes or 'banks', so that they appear to be in a "V" when viewed along the axis of the crankshaft...
s delivering 820 kW (1,100 hp) each. These were more powerful than both those of its Ju 89 predecessor and of production commercial Ju 90s. Named Der Grosse Dessauer, its maiden flight took place on 28 August 1937. Deutsche Luft Hansa carried out the long-distance testing. After eight months of flight tests, this prototype broke up on 6 February 1938 during over-speed tests.
A second prototype (V2) was delivered to Luft Hansa in May 1938
1938 in aviation
This is a list of aviation-related events from 1938:- Events :* Imperial Airways inaugurates scheduled service from London to Montreal. Pan American World Airways is banned from British airports out of fears that more advanced U.S...
for testing. Like all the production commercial Ju 90s, this was powered by four BMW 132
BMW 132
|-See also:-External links:...
radial engine
Radial engine
The radial engine is a reciprocating type internal combustion engine configuration in which the cylinders point outward from a central crankshaft like the spokes on a wheel...
s delivering 620 kW (830 hp). The move to lower power was probably necessitated by the demands on Daimler Benz to produce engines for strategically important, front line aircraft. They named this aircraft Preussen. It crashed fatally during tropical flight tests on takeoff in November 1938 at Bathurst, Gambia, probably because of engine failure.
Despite these setbacks, Luft Hansa ordered eight of the production type A-1.
They also used the next two prototypes, starting with V3 Bayern which flew on the Berlin-Vienna route from July 1938. It is said that this aircraft flew a total of 62,572 km ( mi) in 1938. Only seven of the A-1s were delivered to Luft Hansa, the last in April 1940, one going directly to the Luftwaffe.
South African Airways
South African Airways
South African Airways is the national flag carrier and largest airline of South Africa, with headquarters in Airways Park on the grounds of OR Tambo International Airport in Kempton Park, Ekurhuleni, Gauteng. The airline flies to 36 destinations worldwide from its hub at OR Tambo International...
also ordered two A-1s with Pratt & Whitney Twin Wasp engines delivering 670 kW (900 hp). These were known by the alternative designation Z-3 to distinguish them from the BMW-powered Z-2. Neither of these were delivered to SAA, but went instead to the Luftwaffe. As the war progressed, the surviving six Luft Hansa airframes were also impressed in to Luftwaffe service,
though two were returned to Luft Hansa later. Four of these aircraft took part in the invasion of Norway
Operation Weserübung
Operation Weserübung was the code name for Germany's assault on Denmark and Norway during the Second World War and the opening operation of the Norwegian Campaign...
.
The fourth prototype V4 went into Luftwaffe service in July 941 fitted with 980 kW (1,320 hp) Jumo 211F/L engines.
Military development
1939 in aviation
This is a list of aviation-related events from 1939:-Events:* Kawasaki Heavy Industries transfers its aircraft engine production business to its subsidiary, the Kawasaki Aircraft Engineering Company Ltd....
, the RLM asked Junkers for a further development of the Ju 90 for military transport purposes. The Ju 90V5 and V6 were the prototypes of this military design. They got a new wing with a straight inner section leading edge, of greater span (19%) and area (11%). The landing gear was strengthened with twin main-wheels and the fins were more rounded, lacking the characteristic horn balance nick of the earlier models. The windows were replaced by 10 small portholes a side. The Ju 90 V5 flew first on 5 December 1939. A special feature of both the V5 and V6 was a boarding ramp in the floor of the fuselage for loading cars and larger cargo freight. This ramp, when lowered raised the fuselage to the horizontal flying position. Both aircraft were retrospectively fitted with the much more powerful 1,200 kW (1,600 hp) BMW 801MA radials.
The two last prototypes - the V7 and V8 - fed directly into the Ju 290 development programme. The former had a fuselage extension of 1.98 m (6 ft 6 in) and the addition of dihedral to the tailplane to solve a yaw instability. A reconnaissance prototype aerodynamically similar to the V7, the V8 was armed, however,with two 20 mm MG 151/20 cannon
MG 151 cannon
The MG 151 was a 15 mm autocannon produced by Waffenfabrik Mauser starting in 1940. It was in 1941 developed into the 20 mm MG 151/20 cannon which was widely used on many types of German Luftwaffe fighters, fighter bombers, night fighters, ground attack and even bombers as part of or as...
s and up to nine 13 mm (.51 in) MG 131 machine gun
MG 131 machine gun
The MG 131 was a German 13 mm caliber machine gun developed in 1938 by Rheinmetall-Borsig and produced from 1940 to 1945...
s in two dorsal, one ventral and one tail position.
Ju 290 / 390 development
Some of the Ju 90s were converted into prototypes of the bigger Ju 290 transport and reconnaissance aircraft. The more powerful engines and other modifications to the Ju 90V5 and V7 were steps in this direction and the latter was converted into the Ju 290V3. The Ju 290V8 became the second prototype Ju 290V2. An uncompleted 11th A-series machine was turned into the Ju 290 V1. The Ju 90V6 airframe was used in the construction of the Junkers Ju 390 V1.Numbers and survivors
In the end, only 18 Ju 90s of all versions were completed. Just two survived the war to fall into Allied hands, but both were scrapped soon afterwards.Operators
GermanyNazi Germany
Nazi Germany , also known as the Third Reich , but officially called German Reich from 1933 to 1943 and Greater German Reich from 26 June 1943 onward, is the name commonly used to refer to the state of Germany from 1933 to 1945, when it was a totalitarian dictatorship ruled by...
- LuftwaffeLuftwaffeLuftwaffe is a generic German term for an air force. It is also the official name for two of the four historic German air forces, the Wehrmacht air arm founded in 1935 and disbanded in 1946; and the current Bundeswehr air arm founded in 1956....
- Deutsche Luft HansaDeutsche Luft HansaDeutsche Luft Hansa A.G. was a German airline, serving as flag carrier of the country during the later years of the Weimar Republic and throughout the Third Reich.-1920s:Deutsche Luft Hansa was founded on 6 January 1926 in Berlin...
Specifications (Ju 90A1 aka Ju 90 Z2)
See also
External links
- Four Miles a Minute Sky Sleeper Sleeps Forty, January 1938, Popular Mechanics article with rare photos of JU-90V1 version and interior photos
- WW2 in Color very good information on the JU-90 history