The Junkers Ju 390 was a German long-range derivative of the Junkers Ju 290 aircraft, intended to be used as a heavy transport aircraft, maritime patrol aircraft and long-range bomber.
It was one of the aircraft designs submitted for the failed Amerika Bomber project.
Two prototypes were created by attaching an extra pair of inner-wing segments onto the wings of Ju 290 airframes and adding new sections to lengthen the fuselages.
The first prototype, V1 (bearing Stammkennzeichen code of GH+UK), was modified from the Ju 90 V6 airframe (Werknummer J4918, civil registration D-AOKD from July 1940 to April 1941, then to the Luftwaffe as KH+XC from April 1941 to April 1942, then returned to Junkers and used for Ju 390 V1 construction).
It made its maiden flight on 20 October 1943 and performed well, resulting in an order for 26 aircraft, to be named Ju 390 A-1.
None of these had been built by the time that the project was cancelled (along with Ju 290 production) in mid-1944.
The second prototype, the V2 (RC+DA), was longer than the V1 because it was constructed from a Ju 290 airframe (using the fuselage of Ju 290 A-1 Werknummer J900155).
The maritime reconnaissance and long-range bomber versions were to be called the Ju 390 B and Ju 390 C, respectively.
The Ju 390 V1 was constructed and largely assembled at Junkers’ plant at Dessau in Germany and the first test flight took place on 20 October 1943.
This was done by adding an additional wing section and powerplants and adding a fuselage section immediately aft of the wings to increase the length to 31 m (102 ft).
Its performance was satisfactory enough that the Air Ministry ordered 26 in addition to the two prototypes.
On 29 June 1944, the Luftwaffe Quartermaster General noted that the RLM paid Junkers to complete seven Ju 390 aircraft.
The contracts for 26 Ju 390s were cancelled on 20 June 1944 and all work ceased in September 1944.
On 26 November 1943, the Ju 390 V1 with many other new aircraft and prototypes was shown to Adolf Hitler at Insterburg, East Prussia.
According to the logbook of former Junkers test pilot Hans-Joachim Pancherz, the Ju 390 V1 was brought to Prague immediately after it had been displayed at Insterburg and took part in a number of test flights, which continued until March 1944, including tests of inflight refuelling.
The Ju 390 V1 was returned to Dessau in November 1944, where it was stripped of parts and finally destroyed in late April 1945 as the US Army approached.
Different sources present different accounts of the history of the Ju 390 V2. Kössler and Ott (1993) stated that the Ju 390 V2 was completed during June 1944, with flight tests beginning in late September 1944.
The second prototype (Ju 390 V2) was configured for a maritime reconnaissance role, and its fuselage had been extended by 2.5 m (8.2 ft) for a total of length of 33.5 m (110 ft) and it was said to be equipped with FuG 200 Hohentwiel ASV (Air to Surface Vessel) radar and defensive armament consisting of five 20 mm MG 151/20 cannon.
Green (1970) wrote that the armament was four 20 mm MG 151/20s and three 13 mm (.51 in) MG 131 machine guns.
At a hearing before British authorities on 26 September 1945, Professor Heinrich Hertel, chief designer and technical director of Junkers Aircraft & Motor Works, asserted the Ju 390 V2 had never been completed.
German author Friedrich Georg claimed in his book that test pilot Oberleutnant Joachim Eisermann recorded in his logbook that he flew the V2 prototype (RC+DA) on 9 February 1945 at Rechlin air base.
The log is said to have recorded a handling flight lasting 50 minutes and composed of circuits around Rechlin, while a second 20-minute flight was used to ferry the prototype to Lärz.
Kay (2004) stated that the second Ju 390 prototype was discarded without being flown because of a July 1944 RLM decree sanctioning an end to all large combat plane programs in Nazi Germany in favor of the Emergency Fighter Program.
Pancherz himself stated in 1980 that the only the first Ju 390 flew and cast doubt on all claims of the Ju 390 making a test flight to New York.
Ju 390 V1
Ju 390 V2
10,000 kg (22,046 lb)
34.201 m (112 ft 2.5 in)
50.32 m (165 ft 1 in)
6.88 m (22 ft 7 in)
253.600 m2 (2,729.73 sq ft)
36,900 kg (81,350 lb)
Max take-off weight
75,500 kg (166,450 lb)
34,096 l (9,007 US gal; 7,500 imp gal)
6 × BMW 801E 14-cylinder two-row air-cooled radial piston engines,
1,470 kW (1,970 hp) each for take-off
1,300 kW (1,740 hp) at 1,970 m (6,450 ft)
1,090 kW (1,460 hp) at 6,200 m (20,340 ft)
3-bladed VDM constant-speed propellers
505 km/h (314 mph, 273 kn) at 6,200 m (20,340 ft)
357 km/h (222 mph, 193 kn) at 2,500 m (8,200 ft)
8,000 km (4,970 mi, 4,320 nmi) Ju 390 V1 with 10,000 kg (22,046 lb) payload and 34,096 l (9,007 US gal; 7,500 imp gal) fuel at 330 km/h (210 mph; 180 kn) and 2,000 m (6,500 ft)
9,704 km (6,030 mi, 5,240 nmi) (reconnaissance)
9,254 km (5,750 mi; 4,997 nmi) with 1,930 kg (4,255 lb) bomb load
2 × 20 mm MG 151/20 cannon in dorsal turrets
1 × 20 mm MG 151/20 in tail
2 × 13 mm (.51 in) MG 131 machine guns at waist
2 × 13 mm (.51 in) MG 131s in gondola
Proposed fitment of a pair of 4 x MG 131 Hecklafette HL 131V quad mount manned turrets,