Ju-390 prototypes

Junkers EF100 Project

During 1940 Junkers developed a draft EF53 proposal for a six engined trans Atlantic airliner to win a contract from Deutsch Luft Hansa. The DLH contract was lost to the Bv222 Wiking flying boat and in 1941 the EF53 project was abandoned. What most people today consider was the EF100, was in fact the EF53.   

In 1942 however RLM called for proposals for a maritime patrol aircraft able to reach USA and back. Junkers were encouraged to revise the EF53 proposal as a military aircraft with greater range. In all likelihood the Ju-90B was developed from the EF53 project. The Ju-90S which became the Ju-290 was most likely the militarised version of EF53 for RLM. The draft proposal which followed was the EF100 military patrol transport. This contest was also known as the Amerika Bomber. Messerscmitt proposed the Me-264 as the Amerika Bomber. Focke Wulf offered the Ta-400.

The EF100 was extensively wind tunnel tested and was in fact the forerunner for the Ju-390 prototype built in 1943. The EF100 airliner project was intended to be developed after the war as the Ju-390D.

One or two aircraft ?

A hotly contested argument rages whether a second Ju-390 prototype was ever built. This owes in part to postwar testimony at a British military hearing by Junkers chief engineer for Ju-390 production and similar testimony from the Ju-390 project pilot, Hans Jochim Pancherz who both claimed only one prototype was ever built.

There the story might have ended except that the Ju-390 V1 prototype was retired to the airfield at Dassau and stripped of propellers where it sat conspicuously derelict until destroyed there in 1945. Then Oberleutnant Joachim Eissermann recorded in his log book flying the Ju-390 V2, twice on 9 February 1945. Contrary to modern embellishments, Eissermann's log book did not record the aircraft by it's registration markings. Only that it was the V2 prototype. The first flight was 55 minutes of familiarisation flying around Reichlin air base. The second flight  was a 22 minute delivery trip to Larz.

In their 1993 book, Die Grosen Dessauer: Junkers Ju-89, 90, 290, 390 Karl Kossler and Gunter Ott suggest the second Ju-390 was not constructed and flown before September/October 1944, yet RLM cancelled all Ju-390 contracts in May 1944.

If the Ju-390 contract was canceled in May 1944, then it could not have been completed in September 1944. Kossler and Ott have gotten it wrong.

Soviet historical sources claim the unfinished Ju-390 airframe was in fact the V3 prototype. The Ju-390 V3 prototype was intended for completion in the "summer" of 1944. In fact the original RLM contract in March 1942 was let for three prototypes and we have evidence for the existence of two aircraft. What can be said truthfully is that only one Ju-390 airframe was found in Germany after the War. That is not however conclusive proof that only one was built. 

Evidence for two flying prototypes

I do not speak German and have not read Kossler and Ott's book. I have however read descriptions of the contents by native German speakers and from that source, I understand their book juxtaposes the famous picture of a Ju-390 with Luftwaffe codes RC+DA with another photo of the same aircraft in Luftwaffe codes GH+UK. I understand Kossler and Ott claim the photo of RC+DA is a fake.



If that were true then the aircraft themselves would have identical airframe dimensions. In fact they do not, because they are different aircraft.




In order to better appreciate the difference in airframe proportions it helps to flip one aircraft and match their fuselages alongside each other. Then the different proportions become obvious.



 

Given their other erroneous claims that the V2 must have been constructed after September/October 1944 when in fact the RLM Ju-390 contract was cancelled in May 1944, then it raises serious doubts about the credibility of their book as authoritative research source, or indeed the credibility of their research. Even the most uninformed researcher would have little trouble learning the Nazi Government had ordered all production be switched to fighters in may 1944. The Ju-390 V2 simply could not have been completed after May 1944.

Author Geoffrey Brooks advises me in private correspondence from RLM documents which he has studied, that in June 1944 Junkers was paid for seven Ju-390 prototype aircraft in various stages of completion. 

Aother footnote... Junkers historian Horst Zoeller claims the aircraft marked RC+DA was doctored from another picture of a Ju-290.

In late October 2008 I wrote to Zoeller asking if he could forward me the donor Ju-290 photograph which he says was doctored. I still await a response with interest. I have never seen a photo of a Ju-290 in the same exact pose as RC+DA. His claim is demonstrably false by the Ju-290 photo displayed below. RC+DA has more fuselage ahead of the wing not only when compared with GH+UK, but also when compared with a standard Ju-290. 

Defamatory claims of photo manipulation on Peter Evan's LEMB website

I attach below a photo of the very first Ju-290 aircraft developed from the Ju-90 V11 prototype aircraft. This is the only other photo which I am aware of with a Ju-290 in a similar pose from underneath. On a website known as LEMB the owner there Peter Evans has long permitted members of his forum to personally attack and denegrate me without permitting me access to the website to defend myself against those defamatory claims. Those claims essentially suggest that I have somehow doctored the photo below to create a false image for RC+DA.


Apart from observing what I believe is the cowardice and dishonesty of those participating in those attacks against me, I can only say that I wish I had the skills necessary to manipulate a picture so expertly. I simply don't and for the record the photo of BD+TX has never been manipulated by me or anyone I know. I maintain the angles are all wrong and it can't be done.

I have sufficient skills to rotate a photo and clip or trim... that is the extent of my self taught knowledge.

I challenge anyone to prove how to rotate the image of BD+TX, then alter it's angle of bank and it's perspective as was suggested by one Alfred Mlsna of Vienna. My suggestion to those cowards at LEMB is that it could not be done and nobody has stepped forward with any concrete evidence to show either that this could be done or that they were there and witnessed it done. Forum participants at LEMB assure that Alfred Mlsna knows for certain that it was faked. The inference is made that I faked these photos. I have never met Mr Mlsna in my life nor have I ever been to Vienna and Mr Mlsna has never advised LEMB why he is so confident of his claim.

What I can advise is that I have corresponded with the owner of the original photo of RC+DA which was taken by a British merchant seaman in World War 2. I am satisfied the photograph of RC+DA has a genuine pedigree and that some people are so full of bitter hatred that they make up vindictive untrue stories like school yard bullies.

First Flights


Hans Werner Lerche records his flight in the Ju-390 on 28 October 1943, but makes no comments about this flight at all which is rather surprising if one is asked to accept this was either, the Ju-390's maiden flight, or for that matter personally his first flight in the type. Rather it tends to suggest that he had flown the type before. 

Lerche later disclosed that the Ju-390 was not unpleasant to fly however it could not be flown too fast or turned too quickly otherwise it had a flutter problem. He said it was very stable and slow flying aircraft.

Ju-390 V1

The V1 prototype is often referred to as the "bomber" version. It was employed with FuG 200 Hohentweil radar by FAGr.5 at Mont de Marsan in a maritime reconnaissance role over the Atlantic. Ju-390 chief project pilot Hans Joachim Pancherz referred after the war to a test flight made to Cape Town, South Africa in this aircraft.

The aircraft was constructed at Merkersberg by modification of Ju-90 V6, werke number Wnr 4918 and was first flown 20 October 1943 by Flugkapitan Hans Joachim Pancherz with Dipl Ing. Gast as co-pilot. It's length was increased ahead of the wing from the standard Ju-290's length of 28.6 metres to 31.1 metres.

History records that the Ju-390V1 was longitudinally unstable. The Ju-390 aircraft RC+DA clearly has a greater weight forward and just visually looks as though it would be unstable. What could be termed a visual corroboration. 

Ju-390 V2

The V2 aircraft was an unarmed transport version with a longer fuselage than the V1. It also appears to have been shortened ahead of the wing. This aircraft is reported making it's first flight from Bernberge in August 1943, flown by Flugkapitan Hans Werner Lerche.

V1 appears to have been converted from Ju-90 V9, werke number Wnr 4921. The length of the V2 was increased to 34.2 metres. The fuselage ahead of the wing was also shortened and unlike that on RC+DA was longer aft of the wing. As a pilot I know for a fact that lengthening the fuselage increases the movement arm over the fulcrum at the centre of gravity and thus the longer airframe would be more stable. This would tend to corroborate historical references suggesting the V2 prototype had better stability and identifies GH+UK as the V2 aircraft, not RC+DA

Ju-390 V3

Conversion apparently from Ju-90 V10, werke number Wnr 4922. This aicraft may have been intended as a flying tanker aircraft for air to air refueling trials. Such trials were conducted around Prague with the V1 aircraft in early 1944. Construction of the V3 appears abandoned in May 1944 when all production was switched to emergency fighter construction. 

Ju-390 Construction Ceased June 1944

Conventional historians who assert the existence of only one Ju-390 assert the V2 was broken up before completion. A contrary view is that it was actually the uncompleted V3 aircraft which was broken up in June 1944. By May 1944 orders had already been issued to switch all production to fighters.

On 29 June 1944 KdE Reichlin condemned the Ju-390 saying that it would be unsuitable because the wing was not strong enough for the intended 10,000 payload. That declaration is likely to require some qualification. Reichlin was testing the Ju-390 for an intended role as the Ju-390C bomber at the time to carry three Me-328 parasite aircraft.

The wing was very lightly loaded. The weight of fuel was evenly distributed across it's span. On the ground it had four sets of main undercarriage. For the transport role it was likely quite strong enough. The requirements for a bomber role are quite different, such as requiring higher cruise speeds to avoid interception. 

The Ju-390 had a relatively slow VMO speed of 272 knots. If flown beyond this speed it was likely to break up as would  any aircraft flown in excess of design speeds. This does not imply it was unsafe below VMO.

Fuhrer der Atlantik expressed concern with the Ju-290 type (which very similar characteristics) as being too slow. As a slow transport the Ju-390 had extreme long range and was quite safe. If re-engined to obtain higher speeds and carrying extra weight from gun armament then the Ju-390 likely was inadequate. It was likely that the Ju-390's wing was unsuitable in a specific situation when pushed to higher speeds.

The Ju-90 prototype broke up in mid air when it was pushed to higher speeds than the type was intended for. This is a dynamic effect related to airspeed. Not to structural weakness.

The bomber version of the Ju-390 was intended to launch either parisite fighters or large rocket powered glide bombs at New York. It was the weight of these weapons which the wing was too weak to carry. Not the fuel weight of a mission to New York.

 
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