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The Junkers Ju 287 was a multi-engine tactical jet bomber built in Nazi Germany in 1944. It featured a novel forward-swept wing, and the first two prototypes (which were aerodynamic testbeds for the production Ju 287) were among the very few jet propelled aircraft ever built with fixed landing gear.

Development

thumb|Model of Ju 287 V1 from side bottom view

The Ju 287 was intended to provide the Luftwaffe with a bomber that could avoid interception by outrunning enemy fighters. The swept-forward wing was suggested by the project's head designer Dr. Hans Wocke as a way of providing extra lift at low airspeeds—necessary because of the poor responsiveness of early turbojets at the vulnerable times of takeoff and landing. A further structural advantage of the forward-swept wing was that it would allow for a single massive weapons bay in the best location, the centre of gravity of the plane, with the main wing spar passing behind the bomb bay. The same structural requirement meant the wing could then be located at the best aerodynamic location, the centre of the fuselage. Prior to the assembly of the first Ju 287, an He 177 A-3 (designated as an He 177 prototype, V38) was modified at the Letov plant in Prague to examine the technical characteristics of this single large bomb bay design.

thumb|Rocket engine Walter HWK 109-501 on display at the [[Polish Aviation Museum]]

Flight tests began on 8 August 1944 (pilot: Siegfried Holzbaur), with the aircraft displaying extremely good handling characteristics, as well as revealing some of the problems of the forward-swept wing under some flight conditions. The most notable of these drawbacks was excessive in-flight flexing of the main spar and wing assembly in the manner of wing warping. Tests suggested that the warping problem would be eliminated by concentrating greater engine mass under the wings. This technical improvement would be incorporated in the subsequent prototypes with the under wing engines moved forward under the leading edge as a mass balance. which proved to be unreliable over sustained periods. This initial test phase was designed purely to assess the low-speed handling qualities of the forward-swept wing, but despite this the V1 was dived at full jet power on at least one occasion, attaining a speed in the medium dive-angle employed of 660&nbsp;km/h. To gain data on airflow patterns, small woolen tufts were glued to the airframe and the "behavior" of these tufts during flight was captured by a cine camera mounted on a sturdy tripod directly ahead of the plane's tailfin. After the seventeenth and last flight in September 1944, the V1 was transferred to the Luftwaffe's primary Erprobungsstelle evaluation and test centre at Rechlin, for flow tests. By this time, the Ju 287 program along with the Heinkel He 343 project were shelved to save resources for the Volksjäger emergency fighter program. However, in March 1945, for unknown reasons, the Ju 287 program was restarted, with the RLM issuing a requirement for mass production of the jet bomber (100 airframes a month) as soon as possible.

Postwar development

The Junkers factory in Dessau was overrun by the Red Army in late April 1945. Before long, the Junkers Ju 287 V2 had been almost completed, waiting for its engines to be fitted, and construction of the V3 had reached 80-90 percent completion, while the V4 was reportedly 60 percent complete. Both V1 and V2 were destroyed by the personnel at the Luftwaffe test base in Brandis to avoid capture by Allied forces. Wocke and his staff were captured by the Red Army and taken to the Soviet Union, and remnants of V2, especially the wings, were used in construction of the EF 131 which was flown on 23 May 1947, but by that time, jet development had already overtaken the Ju 287. A final much-enlarged derivative, the EF 140, was tested in prototype form in 1949 but soon abandoned.

Variants

Data from: Junkers Ju 287: The World's First Swept-Wing Jet Aircraft

|prime units?=met

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General characteristics

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|crew=2

|length m=18.30

|span m=20.11

|height m=4.70

|wing area sqm=61

|airfoil=root: Ju 0.9 23 10.7-0.825-40; tip: Ju 0.9 23 12.7-0.825-40

|empty weight kg=12,500

|gross weight kg=20,000

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Powerplant

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|eng1 number=4

|eng1 name=Junkers Jumo 004B-1

|eng1 type=turbojet engines

|eng1 kn=8.825

|eng1 note=

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Performance

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|max speed mph=347

|max speed note=at

|cruise speed mph=318

|cruise speed note=at

|range km=1,570

|ceiling m=9,400

|climb rate ms=9.7

See also

References

Notes

Bibliography

  • Ford, Roger. Germany's Secret Weapons of World War II. London, United Kingdom: Amber Books, 2013. .
  • Green, William. Warplanes of the Third Reich. New York: Doubleday & Company Inc., 1970. .
  • Hitchcock, Thomas H. Junkers 287 (Monogram Close-Up 1). Acton, Massachusetts: Monogram Aviation Publications, 1974. .
  • Jack, Uwe W. Junkers Ju 287 and EF 131: Luftwaffe 6-engine Long-range Aircraft with Forward Swept Wings. N.p.: Jack Aerospace Publishing. 2nd edition, 2021
  • Ju 287