| Ju 287 | |
|---|---|
 | |
| Role | Bomber prototype |
| Manufacturer | Junkers |
| Designer | Philipp von Doepp |
| First flight | 8 August 1944 |
| Number built | 2 |
| Variants | OKB-1 EF 131 |
The Junkers Ju 287 was a Nazi Germany aerodynamic testbed built to develop the technology required for a multi-engine jet bomber. It was powered by four Junkers Jumo 004 engines, featured a revolutionary forward-swept wing, and apart from said wing was assembled largely from components scavenged from other aircraft.
The unfinished second and third prototypes, which far more accurately reflected the design of the eventual production bomber, were captured by the Red Army in the closing stages of World War II and the design was further developed in the Soviet Union after the end of the war.
Development[]
Top view (Model)
Side view (Model)
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 take-off and landing. A further structural advantage of the forward-swept wing was that it would allow for a single massive weapons bay forward of the main wing-spar. Prior to the assembly of the first Ju 287, an He 177 A-5 (designated as a 177 prototype, V38) was modified at the Letov plant in Prague to examine the technical characteristics of this single large bomb bay design.
The first prototype was intended to evaluate the concept, and was cobbled together from the fuselage of an He 177 A-5, the tail of a Ju 188, main undercarriage from a Ju 352, and nosewheels taken from crashed B-24 Liberators. Two of the Jumo 004 engines were hung under the wings, with the other two mounted in nacelles added to the sides of the forward fuselage.
Flight tests began on 16 August 1944 (pilot: Siegfried Holzbaur[1]), 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 'wing warping', or excessive in-flight flexing of the main-spar and wing assembly. 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. The 287 was intended to be powered by four Heinkel-Hirth HeS 011 engines, but because of the development problems experienced with that motor, the BMW 003 was selected in its place. The second prototype, the Ju 287 V2, differed from the Ju 287 V1 in having the main undercarriage struts with an inward cant, the horizontal stabilizer lowered by 30 centimeters, and light grey-colored trouser pants for the nose wheels, it would have had six engines (originally four underwing BMW 003s and two fuselage-mounted Jumo 004s, but later changed to two triple clusters composed three BMW 003s), while the Ju 287 V3 was to employ six of these engines, in a triple cluster under each wing, and it was to have the all-new fuselage and tail design intended for the production bomber, the Ju 287A-1. The Ju 287 V4 was intended as the prototype for the Ju 287A-1, while the Ju 287 V5 and V6 were similar to the Ju 287 V3 and V4 but carried defensive armament and full operational equipment. The Ju 287B-1 was a proposed variant with two underwing pods with three Junkers Jumo 004 engines each, a higher gross weight, and larger landing wheels. about:newTab 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 660kph. 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, the Ju 287 program was halted in late September 1944 along with other German jet bomber programs as Nazi Germany began to increasingly focus on new-generation jet fighters, and the Ju 287 V1 along with the nearly complete Ju 287 V2 were placed in storage at a Luftwaffe flight test center in Brandis. However, in March 1945, for reasons that are not entirely clear, 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, and authorization was given to Junkers to complete the Ju 287 V3 and V4.
Both the Junkers V1 and V2 were blown up by German personnel at Brandis in early 1945 to avoid capture by Allied forces, but on April 16, US Army units captured the Brandis flight test center, and several days later they overran the Junkers factory building the Ju 287 V3 and V4, by which time the Ju 287 V3 and V4 were in varying stages of completion. The Red Army occupied Dessau in the early summer of 1945. Hans Wocke and his staff, along with the two incomplete prototypes, were taken to the Soviet Union. A Jumo 004B-powered version of the Ju 287, the EF 131) was eventually finished in 1946 and 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 late 1948 but soon abandoned.
Specifications (Ju 287 V1)[]
Data from [2]
General characteristics
- Crew: 2
- Length: 18.30 m (60 ft 0 in)
- Wingspan: 20.11 m (66 ft 0 in)
- Height: 4.70 m (15 ft 5 in)
- Wing area: 61 m2 (660 sq ft)
- Empty weight: 12,500 kg (27,558 lb)
- Gross weight: 20,000 kg (44,092 lb)
- Powerplant: 4 × Junkers Jumo 004B-1 turbojet engines, 8.825 kN (1,984 lbf) thrust each :::Ju 287 V2 and Ju 287 V3: 6 x Junkers Jumo 004B-1
Performance
- Maximum speed: 558 km/h; 302 kn (347 mph) at 6,000 m (19,685 ft)
- Cruise speed: 512 km/h; 276 kn (318 mph) at 7,000 m (22,966 ft)
- Range: 1,570 km (976 mi; 848 nmi)
- Service ceiling: 9,400 m (30,840 ft)
- Rate of climb: 9.67 m/s (1,904 ft/min)
See also[]
References[]
Notes[]
Bibliography[]
- Green, William. Warplanes of the Third Reich. New York: Doubleday & Company Inc., 1970. ISBN 0-385-05782-2.
- Hitchcock, Thomas H. Junkers 287 (Monogram Close-Up 1). Acton, Massachusetts: Monogram Aviation Publications, 1974. ISBN 0-914144-01-4.
- Ransom, Stephen, Peter Korrell and Peter D. Evans.Junkers Ju 287. Hersham, UK: Ian Allan, 2008. ISBN 978-1-903223-92-5.
External links[]
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