| Ju 86 | |
|---|---|
 Ju 86K-2 of Royal Hungarian Air Force, showing the JunkersDoppelflügel wing control surfaces | |
| General information | |
| Type | Bomber,airliner,reconnaissance aircraft |
| Manufacturer | Junkers |
| Designer | Ernst Zindel[1] |
| Status | retired |
| Primary user | Luftwaffe |
| Number built | ~900 |
| History | |
| Introduction date | 1936 |
| First flight | 4 November 1934 |
| Retired | 1958 (Swedish Air Force) |
TheJunkers Ju 86 is amonoplanebomber and civilianairliner designed and produced by theGerman aircraft manufacturerJunkers.
It was designed during the mid-1930s in response to a specification for a modern twin-engined aircraft suitable for use as both a high-speed airliner and a bomber. Junkers responded with a low-winged twin-engined all-metalmonoplane; unusually, it was intended to be powered byJunkers Jumo 205diesel engines instead ofpetrol engines for greater fuel efficiency. It also had a smooth metal skin instead of the company's traditionalcorrugated exterior. On bomber-configured aircraft,bombs were carried vertically in four fuselage cells behind the cockpit; these bomb cells were replaced by seating for up to ten passengers on the civil airliner version of the Ju 86. On 4 November 1934, the first prototype, powered bySiemens SAM 22radial engines, made itsmaiden flight; on 4 April 1935, the third prototype, which was the first civil-configured aircraft, flew for the first time.
The civil-oriented Ju 86 models were operated by a range of airlines, including the Germanflag carrierDeutsche Luft Hansa,Manchukuo National Airways,South African Airways,Iberia Airlines andAB Aerotransport amongst others. Some civilian aircraft would be converted into military aircraft following the outbreak of theSecond World War. The type was employed by various air forces on both sides of the conflict, although the first military use of the Ju 86 was during theSpanish Civil War, where it was flown by theCondor Legion with mixed results. TheLuftwaffe deployed its Ju 86s during theinvasion of Poland, but opted to withdraw its diesel-engined aircraft fairly promptly while the radial-engined Ju 86 models were predominantly assigned to training roles thereafter. During late 1942, Ju 86s, along with all other available transport aircraft, were pulled from training schools to reinforce theLuftwaffe's transport force in its attempt to supply the German6th Armybesieged at Stalingrad, although this attempt was soon ended due toSoviet advances.
The Ju 86P, which emerged in early 1940, could reach high altitudes because of its longerwingspan,pressurized cabin, andJunkers Jumo 207A-1 turbocharged diesel engines. It was used for reconnaissance aircraft and as a nuisance bomber over England until interception by modifiedSupermarine Spitfires led to its withdrawal. At one point, Junkers was developing theJu 86R, fitted with even larger wings and new engines, to attain even higher altitudes, but this model never progressed beyond the prototype stage. Today, only a single Ju 86 is known to exist; it is on permanent static display at theSwedish Air Force Museum outsideLinköping.
The origins of the Junkers Ju 86 are closely linked to the clandestine build-up ofLuftwaffe during the mid-1930s.[2] During 1934, the recently created GermanReichsluftfahrtministerium (RLM) and the Germanflag carrierDeutsche Luft Hansa worked together to produce a specification for a twin use aircraft, capable of operating both as a high-speed airliner for Deutsche Luft Hansa and as a medium bomber for the Luftwaffe. Distinct civil and military variants of the aircraft were sought; however, where the requirements were not fully compatible with one another, it was deemed that military needs took precedence over those of the civil side of the programme.[3][2]
Two German aircraft manufacturers,Junkers andHeinkel, were both approached regarding this specification; each company received an initial order for five prototypes (three military and two civil) of their designs, these being the Ju 86 andHeinkel He 111 respectively.[3][4] Junkers' opted for a low-winged twin-enginedmonoplane that featured all-metalstressed skin construction. Unlike the majority of Junkers' previous designs, the Ju 86 discarded the typical corrugated skinning in favour of smooth metal skinning, which helped to reducedrag.[5] It was intended to be powered byJunkers Jumo 205diesel engines, which although heavy, gave better fuel efficiency than conventionalpetrol engines.[3] This decision made the Ju 86 one of the earliest quantity production aircraft to use diesel propulsion.[2]
The wing of the Ju 86, which was tapered, comprised two primaryspars and one auxiliary spar.[4] It was outfitted with distinctive Junkersdoppelflügel control surfaces on the wing, similar to those on theJunkers Ju 52, that were hinged below the wing's trailing edge, with the outboard section on each side functioning as anaileron, and the inner section functioning as awing flap.[6][4] The aircraft was fitted with a retractable main-gearconventional undercarriage with a fixedtailwheel, andtwin fins and rudders. Unusually, the main undercarriage members were attached to thewing roots and outwardly retracted into recesses within the wings; this arrangement meant that the undercarriage had a particularly narrow track.[4]
The bomber aircraft had a crew of four: a pilot, navigator, radio operator/bombardier and gunner. Defensive armament consisted of threemachine guns: at the nose, at a dorsal position, and within a retractable ventral position.Bombs were carried vertically in four fuselage cells behind the cockpit.[6] The airliner version replaced these bomb cells with seating for ten passengers; furthermore, the fuel tanks were relocated from the fuselage to the wings.[7]
As the Jumo 205 was unavailable when the first prototype airframe was completed, the bomber-configured Ju 86ab1 was fitted withSiemens SAM 22radial engines instead when it performed itsmaiden flight on 4 November 1934.[3][4] Early flight trials were reportedly demonstrated the prototype to possess unsatisfactory control and stability; modifications were made.[4] The second prototype, which was also a bomber, flew during January 1935. The third Ju 86, the first civil prototype, flew on 4 April 1935.[7][4] The fourth and fifth prototypes, which were more representative of production aircraft, were furnished with a new wing design with an increasedchord, and thereby wing area, towards the tips.[8]
During late 1935, production of both pre-series military and civil aircraft commenced.[7] In April 1936, full-rate production of the Ju 86A-1 bomber was achieved. Many of the early modifications made were centred around increasing the aircraft's stability, such as the addition of a spine-like dorsalfin on the tail end of the fuselage on the Ju 86C.[9] Production was quickly transitioned to the improved Ju 86D, the chief differences of which being a modified tail cone that improved stability and an almost 50 per cent increase in fuel capacity over that of the Ju 86A.[10][11] During the late 1930s, demand for the type was such that rival firmHenschel became involved in the production program.[12]
Early use of the Jumo-powered Ju 86 bomber in theSpanish Civil War showed that it was inferior to the He 111, with the diesel engines being unsuitable for rough treatment during combat and thus difficult to keep operational.[13][12] Accordingly, production plans of the type were promptly cut back. One Ju 86 had already been converted to use radial engines as a testbed for possible export versions, and this showed improved reliability. Production switched to a version powered by theBMW 132 engine, the Ju 86E, the production of which continued though to 1938.[14][12] The sudden end to production without advance warning meant that there were still enough component parts to construct a further 1,000 aircraft.[15]
While the Ju 86 was deemphasised as a bomber as time went on, Junker opted to continue development of the aircraft as a high altitude platform for both reconnaissance and bombing missions.[12] TheJu 86P, which possessed a longerwingspan,pressurized cabin,Junkers Jumo 207A-1 turbocharged two-stroke, opposed-piston diesel engines and a two-man crew, could fly higher than 12,000 m (39,000 ft), where it was felt to be safe from enemyfighters. Furthermore, it could be produced by remanufacturing existing Ju 86D airframes.[16]
During early 1942, Junkers was working on the Ju 86R, which used even larger wings and new engines and was reportedly capable of reaching even higher altitudes – up to 16,000 m (52,500 ft) – in order to continue evading increasingly advanced interceptors.[17] While a few aircraft were built and delivered to theLuftwaffe during 1943, production was limited to a small quantity of aircraft. Further advanced models, such as the Ju 86 R-3 and the Ju 186, but these never left the drawing board.[18]
Civil variants, introduced in 1936, were designated Ju 86Z in three different models differing in their engines.[19] The Jumo-engined Ju 86Z-1 (corresponding to the former B-0 or C-1) was sold to Swissair (one), Airlines of Australia (one), andLAN-Chile (three).[20] The BMW 132H-powered Ju 86Z-2 was sold to DLH (two) and the para-military Manchukuo Air Transport (five or more). ThePratt & Whitney R-1690 Hornet-engined Ju 86Z-7 was delivered toAB Aerotransport (ABA) of Sweden (one, for use as a mail carrier),Lloyd Aéreo Boliviano (three), andSouth African Airways (SAA) (seventeen). The ABA aircraft was later transferred to theSwedish Air Force, with which it served, under the designation Tp 9, until 1958. South African Airways' original intention was to have its Ju 86s powered by 745 hpRolls-Royce Kestrels. Six aircraft for SAA, flown with these engines, were refitted with Hornets before delivery, and the remainder were also Hornet-powered.[citation needed]
TheJu 86K was an export model, alsobuilt under license in Sweden by Saab as the B 3 with (905 hp)Bristol Mercury XIXradial engines. Several aircraft remained in service with theSwedish Air Force until 1958.[21] A few were converted forradio interception activities.[22]
The bomber was field-tested in theSpanish Civil War by theCondor Legion. Four Ju 86D-1s arrived in Spain in early February 1937, but after a few sorties one of them was shot down in late February–early March 1937 byRepublican fighters. A replacement aircraft was sent from Germany, but after two more were damaged in landing accidents, the remaining two aircraft were sold to theNationalist air force, where they remained in service until at least the end of the Civil War. The Ju 86 had proved to be generally inferior to theHeinkel He 111 evaluated at the same time.[23]
A singleGruppe of Ju 86 bombers (III KG 1 "Hindenburg") remained in operational service at the start of theSecond World War and were used in theinvasion of Poland, but replaced soon after. The diesel-engined Ju 86A and Ds were quickly retired while the radial-engined Ju 86E and Gs were transferred to bomber training schools.[24] Soon after the conflict started, theLuftflotte (Air Fleet) commanders raided their training schools forJu 52s as transport aircraft, together with their experienced aircrew instructors.[25] This depletion continued with the formation of special bomber crews for the invasions ofNorway, theLow Countries, andCrete.[26] This was to a severe blow to the pilot training programme, andOberstleutnant Lt-ColonelPaul Deichmann, Chief of Staff to the Luftwaffe's Chief of TrainingHelmuth Wilberg suggested that Ju 86s with dual controls and instruments could be easily produced to replace the appropriated Ju 52s. However, his contention that "the need for air transport services would soon reach tremendous proportions" was simply brushed aside by the commander-in-chief of theLuftwaffe,Hermann Göring.[15]
In late 1942, all available aircraft, including Ju 86s, were pulled out of the training schools to reinforce theLuftwaffe's transport force in its attempt to supply the German6th Army,besieged at Stalingrad. The Ju 86s formed two transportGruppen, equipped with 58 aircraft, operating out ofTatsinskaya Airfield. They were unsuited to the transport role, and suffered heavy losses (42 Ju 86s were lost by the end of January 1943) before being forced out of the airlift when the Soviets captured Tatsinskaya, not having the range to reach Stalingrad from the replacement airfields.[24][27] More than 40 Ju 86s were lost in this endeavour while the survivors were reallocated to training bomber crews.[24][28]
Ju 86s operated by the Allies in the Second World War included 17[29][a] early-model units that had been in use bySouth African Airways. When the conflict broke out, these aircraft were militarised and armed as bombers with defensive guns and external bomb racks. These aircraft were initially used for coastal patrols along with the sole Ju 86K-1, playing an important role in the interception of the Germanblockade runnerSSWatussi [de] in December 1939. In May 1940, they were used to re-equipNo. 12 Squadron SAAF, which was deployed in theEast African Campaign from June 1940. It flew its first bombing missions on 14 June 1940.[31] As more modern aircraft became available, the South African Ju 86s were passed from squadron to squadron, seeing their last use withNo. 22 Squadron SAAF, which used it along with theAvro Anson in the coastal reconnaissance role, finally retiring its Ju 86s in September 1942.[32]
During March 1939, Hungary used its Ju 86s to bombSlovakian airfields and defensive positions during theSlovak–Hungarian War. From June 1941, Hungary's Ju 86s began to be replaced by ItalianCaproni Ca.135 bombers. An independent bomber squadron, equipped with a mix of Ju 86s and Ca 135s was deployed in support of the HungarianGyorshadtest (or Fast Corps) duringthe German-led invasion of the Soviet Union. However, the Ju 86 was withdrawn from front line service by Hungary during 1942.[33]
In January 1940, theLuftwaffe evaluated the prototypeJu 86P, which could fly higher than 12,000 m (39,000 ft), where it was felt to be safe from enemyfighters.[34] The BritishWestland Welkin and SovietYakovlev Yak-9PD were developed specifically to counter this threat.[35] Satisfied with the trials of the Ju 86P prototype, theLuftwaffe ordered that some 40 older-model bombers be converted toJu 86P-1 high-altitude bombers andJu 86P-2 photo-reconnaissance aircraft, with pressurized fuselage, no armament, and a crew of two.[29][36]
The Ju 86P operated successfully for some years over Britain, theSoviet Union and North Africa.[17] During early 1941, the reconnaissance version flew sorties over Britain, but these stopped when Hitler invaded Russia (Operation Barbarossa). By mid-1942, the pressurized bomber version was available, and flew about a dozen nuisance raids over southern England.[b] The RAF created a special interception squadron equipped with modifiedSupermarine Spitfire Mk IXs, leading to one bomber attempting a raid onPortsmouth being intercepted and damaged on 12 September 1942. After this, no further flights over England were attempted.[29] In August 1942, a modified Spitfire Mk V shot down a Ju 86P overEgypt at an altitude of 14,500 m (49,000 ft). After the loss of two more aircraft, the Ju 86P was withdrawn from service in 1943.[17]
A single unit operated theJu 86R, which was capable of even greater altitudes than the Ju 86P, between 1943 and mid 1944.[17]
Only one Junkers Ju 86 is known to exist today. The aircraft was built in Germany and sold to Sweden in 1938. Before it was retired from Swedish service in 1958, the aircraft was used in the 1955 movieDes Teufels General. It is on permanent static display at theSwedish Air Force Museum nearLinköping.[37]
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Data fromThe warplanes of the Third Reich,[48]Jane's Fighting Aircraft of World War II[49] and Warbirds Resource Group[50]
General characteristics
Performance
Aircraft of comparable role, configuration, and era
Related lists
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