Focke Wulf (Tank) Ta 154 / Ta 254

[newsdeskdan]

Having done some more research, it seems the evolution of the Ta 254 configuration went like this:
April 1, 1944.
Two types - two-seater A-1 and single-seater A-2:


May 24, 1944.
Two types - two-seater A-1 and two-seater A-2:


May 31, 1944.
Four types - two-seater A-1, two-seater B-1, two-seater A-3 and two-seater B-3:


June 10, 1944.
Two types - two-seater A-3 and two-seater B-3.


It seems like both the A-1 and A-2 were deleted prior to the Ta 254's cancellation. Maybe due to the supposedly imminent availability of the DB 603 L and the non-availability of the MK 108 (all needed for Me 262 production). It's not entirely clear how long the A-2 existed as a single-seater for, but probably slightly longer than it existed as a two-seater.

 

[napobona]

@newsdeskdan thank you for sharing this. I believe this information is in none of the current publications.
I'm surprised that the day-fighter converged to a two-seater. Especially because it doesn't say anything about defensive armament.
I'm also attaching images from 'Luftfahrt History- Focke Wulf Fw Ta 154 und Ta 254'. The images feature the 254 A-2 canopy and BK 5 installation drawings into a 154 C-?.

 

[spicmart]

I wonder why would Focke Wulf go with a minimalist nightfighter design (Ta 154) in the first place when the requirement for a larger aircraft (Ta 254) was foreseeable to emerge?
Planning such a larger plane from the get-go would have saved time and efforts later on.

 

[Grey Havoc]

As a potential stopgap design for rapid introduction into production perhaps?

 

[Basil]

As a potential stopgap design for rapid introduction into production perhaps?

Generally correct. You will find the details in Dietmar Hermann's book.

 

[Justo Miranda]

The lack of reliable wood adhesive doomed the entire production system, including the use of heavy cannons. In my opinion the wooden structure would hardly have supported the recoil, even the British Mosquito had problems with the Molins cannon.

 

[Arjen]

In my opinion the wooden structure would hardly have supported the recoil, even the British Mosquito had problems with the Molins cannon.

The DH Mosquito F.B. VI and the later DH Hornet functioned perfectly fine with four 20 mm cannon, despite their wooden construction. The F.B. VI had an additional four rifle calibre Brownings. The Molins 6pdr gun was a handful, possibly a bridge too far for the Mosquito. Even so, big gun Mosquitoes- Tsetses - shot down at least one Ju 88, taking out a complete engine with one shell, and sinking or heavily damaging several German submarines.
The failure of the Ta 154 was a manufacturing process failure, <edit> See @newsdeskdan reply #132</edit> Mosquito and Hornet showed wooden construction and a heavy cannon armament (and more, as in the F.B. VI and Tsetse) were compatible, if the aircraft were competently built, and competently designed. Even with a Molins 6pdr.

The lack of reliable wood adhesive doomed the entire production system

Yes. <edit> No. </edit>

 

[spicmart]

The lack of reliable wood adhesive doomed the entire production system, including the use of heavy cannons. In my opinion the wooden structure would hardly have supported the recoil, even the British Mosquito had problems with the Molins cannon.

IIRC the adhesive issue was not as grave as it was made up to be in post-war articles as Tank said (in one or both of Hermann's Ta 154 books) that it had been sorted out and it hasn't been mentioned since.

 

[Foo Fighter]

I heard the main plant producing the glue was destroyed, Callum mentioned another source for the product or perhaps a different process, ICR.

 

[robunos]

I heard the main plant producing the glue was destroyed, Callum mentioned another source for the product or perhaps a different process, ICR.

That's my understanding as well, also that the original glue was 'Tego Film', a 'modern' resin type, while the replacement was an old fashioned 'paint it on then let it dry' type glue.
Ah, here we are, from Wiki :-
"When Germany attempted to emulate this aircraft [the De Havilland Mosquito] with the Ta 154 Moskito, it used Tego film.
Flight testing and development of the first Tego film-bonded prototypes from summer 1943 to 1944 was highly successful, but RAF bombing of Wuppertal in February 1943 had already destroyed the only factory producing Tego film.
For the production aircraft, an ersatz cold adhesive was used. During a test flight on 28 June 1944, one of the two aircraft broke up in flight. Investigation showed that the glue left an acidic residue after curing, that in turn damaged the structure of the timber. Mass production of the aircraft never took place after this."

cheers,
Robin.

 

[spicmart]

That's my understanding as well, also that the original glue was 'Tego Film', a 'modern' resin type, while the replacement was an old fashioned 'paint it on then let it dry' type glue.
Ah, here we are, from Wiki :-
"When Germany attempted to emulate this aircraft [the De Havilland Mosquito] with the Ta 154 Moskito, it used Tego film.
Flight testing and development of the first Tego film-bonded prototypes from summer 1943 to 1944 was highly successful, but RAF bombing of Wuppertal in February 1943 had already destroyed the only factory producing Tego film.
For the production aircraft, an ersatz cold adhesive was used. During a test flight on 28 June 1944, one of the two aircraft broke up in flight. Investigation showed that the glue left an acidic residue after curing, that in turn damaged the structure of the timber. Mass production of the aircraft never took place after this."

cheers,
Robin.

I would take Wikipedia with a grain of salt.

 

[newsdeskdan]

Seems like Dietmar Hermann was right. The Ta 154/254 wasn't cancelled due to glue issues - it was cancelled because the Ju 388 could do everything it could do but better. A proposal to cancel it for this reason was tabled at a meeting of the Jaegerstab on June 16, 1944, and the order was issued for a total stop of Ta 154/254 production on June 23, 1944.

The 'it was the glue that was the problem' notion seems to come from a 1955 book, Nerven, Herz und Rechenschieber. This was a very flattering biography of Kurt Tank by one of his former senior managers - Heinz Conradis. Conradis colourfully describes a meeting wherein Kurt Tank cancels the Ta 154 himself (!), not because of the aircraft's mediocre performance but because of the glue.

The book says:
Goering bit his lip. "Ask Milch," he murmurered to an aide. Then he bade Tank go on.
"The prototype of the Ta 154 took off 11 months later and gave general satisfaction. It had the necessary performance: about 430mph. It was the fighter they need to deal with the Mosquito. The RLM was extraordinarily quick in putting in an order. I only had to wait three months before I was told to build 250 of them. And so the work went ahead. It is that series the production of which I have just halted."
[Goering:] "You have halted it! If that order is to be given, I am the only person who can give it! Start it up again, start it up again!"
Tank replied firmly: "While I am in charge of my show, the Ta 154 production will remain blocked unless and until I'm convinced the new glue is strong enough."
"The glue is perfectly all right," put in the Erfurt man. "All the joints are as strong as you need them."
Tank spoke very sharply when he answered. "But the acid in the glue rots the wood near the joints. We have tried it and there's not the least doubt. The firm that produces the glue advises a mixture of one part gum to five of water, but that is not enough to neutralise the acidity. It eats into the wood and makes it rotten in a matter of weeks. You naturally didn't push your experiments that far at Erfurt. But we did. We shall get it right soon enough. We're experimenting with seven parts of water instead of five. But I can't say too forcibly that, until I'm satisfied with the findings of our chemists, not a wing will be made."
The man from the RLM broke in to point out that the three prototype models had held well enough, but again Tank knew the answer. "Those were built with the old Tego-Film gum, which was first-rate stuff. Goldmann of Wuppertal made it."
There was a fresh outburst from Goering. "Then stop trying out new glues in the middle of a war. Go on using the Wuppertal stuff. I suppose that's another decision you took on your own authority?"
"The Wuppertal factory was destroyed just before we began mass production. I'm not responsible for that."
By this time Tank had become excited, and stood up behind his chair, banging it with both hands.
"If I neglected to test the glue thoroughly," he affirmed, "so that as a result one single aeroplane crashed, or one German airman died, then indeed I should be guilty of something. I am not prepared to take that responsibility."

How much of this is true remains to be seen. According to Hermann, TEGO wasn't made by Goldmann but rather Theodor Goldschmidt and Goldschmidt didn't even have a factory at Wuppertal.
Whatever the case, glue doesn't seem to have factored into the decision to cancel the aircraft at all. The decision was made purely on performance. Basically, the Ta 154 was rubbish. The Ju 388 was just better and at the same stage of development. The Do 335 was a LOT better but was further behind in development. Nevertheless, with those two in progress, building the Ta 154 was deemed pointless.
Also, the cancellation order came from Saur, not Goering or Tank.

Somewhat remarkably, the Ta 154 isn't mentioned even once in the equally flattering biography of Milch, The Rise and Fall of the Luftwaffe by David Irving (even the Ta 153 gets a mention - but not the Ta 154!). Perhaps that's because the Ta 154 concept was Milch's idea in the first place (him and William Werner) and he didn't want to be associated with such a miserable failure of an aircraft.

 

[spicmart]

Seems like Dietmar Hermann was right. The Ta 154/254 wasn't cancelled due to glue issues - it was cancelled because the Ju 388 could do everything it could do but better. A proposal to cancel it for this reason was tabled at a meeting of the Jaegerstab on June 16, 1944, and the order was issued for a total stop of Ta 154/254 production on June 23, 1944.

The 'it was the glue that was the problem' notion seems to come from a 1955 book, Nerven, Herz und Rechenschieber. This was a very flattering biography of Kurt Tank by one of his former senior managers - Heinz Conradis. Conradis colourfully describes a meeting wherein Kurt Tank cancels the Ta 154 himself (!), not because of the aircraft's mediocre performance but because of the glue.

The book says:
Goering bit his lip. "Ask Milch," he murmurered to an aide. Then he bade Tank go on.
"The prototype of the Ta 154 took off 11 months later and gave general satisfaction. It had the necessary performance: about 430mph. It was the fighter they need to deal with the Mosquito. The RLM was extraordinarily quick in putting in an order. I only had to wait three months before I was told to build 250 of them. And so the work went ahead. It is that series the production of which I have just halted."
[Goering:] "You have halted it! If that order is to be given, I am the only person who can give it! Start it up again, start it up again!"
Tank replied firmly: "While I am in charge of my show, the Ta 154 production will remain blocked unless and until I'm convinced the new glue is strong enough."
"The glue is perfectly all right," put in the Erfurt man. "All the joints are as strong as you need them."
Tank spoke very sharply when he answered. "But the acid in the glue rots the wood near the joints. We have tried it and there's not the least doubt. The firm that produces the glue advises a mixture of one part gum to five of water, but that is not enough to neutralise the acidity. It eats into the wood and makes it rotten in a matter of weeks. You naturally didn't push your experiments that far at Erfurt. But we did. We shall get it right soon enough. We're experimenting with seven parts of water instead of five. But I can't say too forcibly that, until I'm satisfied with the findings of our chemists, not a wing will be made."
The man from the RLM broke in to point out that the three prototype models had held well enough, but again Tank knew the answer. "Those were built with the old Tego-Film gum, which was first-rate stuff. Goldmann of Wuppertal made it."
There was a fresh outburst from Goering. "Then stop trying out new glues in the middle of a war. Go on using the Wuppertal stuff. I suppose that's another decision you took on your own authority?"
"The Wuppertal factory was destroyed just before we began mass production. I'm not responsible for that."
By this time Tank had become excited, and stood up behind his chair, banging it with both hands.
"If I neglected to test the glue thoroughly," he affirmed, "so that as a result one single aeroplane crashed, or one German airman died, then indeed I should be guilty of something. I am not prepared to take that responsibility."

How much of this is true remains to be seen. According to Hermann, TEGO wasn't made by Goldmann but rather Theodor Goldschmidt and Goldschmidt didn't even have a factory at Wuppertal.
Whatever the case, glue doesn't seem to have factored into the decision to cancel the aircraft at all. The decision was made purely on performance. Basically, the Ta 154 was rubbish. The Ju 388 was just better and at the same stage of development. The Do 335 was a LOT better but was further behind in development. Nevertheless, with those two in progress, building the Ta 154 was deemed pointless.
Also, the cancellation order came from Saur, not Goering or Tank.

Somewhat remarkably, the Ta 154 isn't mentioned even once in the equally flattering biography of Milch, The Rise and Fall of the Luftwaffe by David Irving (even the Ta 153 gets a mention - but not the Ta 154!). Perhaps that's because the Ta 154 concept was Milch's idea in the first place (him and William Werner) and he didn't want to be associated with such a miserable failure of an aircraft.

I thought with Jumo 213E and up the Ta 154/254 delivered good enough performance?

 

[Dagger]

After the "Big Week" bombardments (20 - 25 Februari 1944) aircraft production facilities had to be rebuilt.
The "Jägerstab" was formed on 1 March 1944 to decide on what aircraft types to focus production, and which to cancel.
This resulted in less different types for same purpose, more fighters, less attack aircraft.

During a meeting on 23 - 25 May at the Obersalzberg Göring already wanted to cancel the Ta 154/254 but Tank managed to convince hime that the glue problem was solved. According to Dietmar Hermann in a 'Flugzeug Classic' article:



Then on 6 June D-day happened, and soon the decision was made to focus aircraft production on a limited number of fighter types only. The Ta 154/254 and Me 210/410 production were cancelled. Moreover no new heavy attack aircraft or bomber production, again according to Dietmar Hermann in 'Flugzeug Classic' :

 

[Justo Miranda]

The problem with the Kaurit adhesive was the excessive acidity of the stabilizing component, it is true that the manufacturing process could be modified, but not with the resources of the German chemical industry in 1944. Most of the resources were allocated to the V-weapon program and the manufacture of explosives for the Flak. They could not even manufacture enough benzol and the production of the hydrogenation plants was only decreasing due to the continuous bombardments, the synthetic rubber varied greatly in quality according to the month of manufacture due to the different raw materials used. Germany could not afford experiments.

 

[robunos]

I would take Wikipedia with a grain of salt.

Only a grain . . . ?

cheers,
Robin.

 

[newsdeskdan]

During a meeting on 23 - 25 May at the Obersalzberg Göring already wanted to cancel the Ta 154/254 but Tank managed to convince hime that the glue problem was solved. According to Dietmar Hermann in a 'Flugzeug Classic' article:

Hermann doesn't include the full stenographic transcript for obvious reasons. The full thing begins in classic Goering style (see below) with a humorous comment - calling the Ta 154 the 'problem child from Nuremberg'.

I don't know if Hermann mentions the timing of this particular extract. It's from almost the very end of the three-day meeting - May 25. Two days earlier, on May 23, the Ta 154 - its problems, its performance and its wider situation had already been discussed at length by Goering with Knemeyer, Milch, Galland and others without Tank present. I think maybe there was no move to actually cancel it at this stage - Goering was just yanking Tank's chain.

The discussion on May 25 actually goes on way, way longer than Hermann seems to indicate and goes quite exensively into the question of performance.

 

[Apophenia]

All this adhesive stuff gets confusing. We know that Tegofilm production was cut short by Allied bombing. The Wiki.de page on the Ta 154 says:

Die Alliierten waren durch ihre Luftaufklärung von Beginn an über die Entwicklung und den Bau der Ta 154 unterrichtet. Im Rahmen mehrerer Präventivschläge gegen die Erprobungs- und Fertigungsstätten von Focke-Wulf, wobei vornehmlich Bomber vom Typ B-17 und B-24 zum Einsatz kamen, wurden die Standorte zur Entwicklung und Erprobung der Ta 154 getroffen, darunter auch die für die Leimproduktion verantwortliche Firma Th. Goldschmidt in Wuppertal.

-- https://de.wikipedia.org/wiki/Focke-Wulf_Ta_154

So, in response to prototype development, the Allies launched preventative bombing strikes on Focke Wulf testing sites and key suppliers - including the maker of Tegofilm, Th. Goldschmidt A.G. (now Evonik). A subsidiary site at Wuppertal is specifically mentioned - although, in typical Wiki fashion, the referenced page makes zero mention of Wuppertal. Despite being mentioned here by Wiki.de, that association of Goldschmidt with Wuppertal seems to have originated with Allied intelligence. Anyway, as Dan has already pointed out, Goldschmidt didn't have a Wuppertal plant. [1]

The loss of Tegofilm would be critical because its use had demanded the procurement of dedicated presses. In other words, any replacement adhesive product would, ideally, also suit those presses. One potential replacement might have been Goldschmidt's Tegoleim - a low-cost adhesive using phenol-formaldehyde condensation to produce a thermosetting polymer. What is not clear is whether those Tegofilm-specific presses would be needed (or even useful). And, in any case, probably both Tegoleim and Tegofilm were actually produced at the heavily bombed Th. Goldschmidt A.G. Essen facility (85% destroyed by war's end).

That "ersatz cold adhesive" mentioned by Robin was the replacement adhesive Kaurit. And here too there is confusion. Multiple online sources wrongly attribute Kaurit to Dynamit A.G. [2] In any case, Kaurit - still made by BASF - was actually a wartime product of the infamous I.G. Farbenindustrie A.G. [3] Kaurit is an impregnating urea-formaldehyde resin which required pressing at 100°C ... immediately posing the question: were Tegofilm presses suited to those temperatures?

Sorry for an OT, but since this is already so long ... can I also ask if anyone is aware of the use of Dynamit A.G.'s I-Gummi? This I-Gummi came about in 1943 and (machine trans.) "whose polyester component was made up of adipic acid, glycol and very small amounts of glycerine". I'm just curious as to what it was used for ... as I am for Raschig Imprenol, another PF adhesive. Thanks in advance.

_________________________________

[1] In the unlikely event that any doubts still remain, see the history section of the Evonik website - which has pages for all related facilities (active and former) with nary a mention of Wuppertal. -- https://history.evonik.com/en/locations

[2] Troisdorf-based Dynamit A.G. did make a wartime PF condensation product but I cannot uncover its name - annoyingly and unhelpfully, it is mostly just referred to as a klebstoff.

[3] Despite its failure in Ta 154 construction, Kaurit was successful in other uses (eg: wartime use in making German rifle stocks). Kaurit was designed for aircraft construction but its inventor, Hanns Klemm (hence Klemmleim as another name for Kaurit), was probably thinking of light aircraft (like his Kl 105), not high-speed fighters.

 

[newsdeskdan]

As Hermann mentions, a glue called P 600 seems to have been the favoured replacement for Tegofilm. This was the glue used on the He 162 and was made by Dynamit. So this may be the klebstoff in question, Apophenia.

 

[tomo pauk]

@ knowledgeable people here: how much the wing construction of the Me 162 differed from that of the Ta 154, former being good enough to reach speeds unheard of at the time?

 

[Basil]

I thought with Jumo 213E and up the Ta 154/254 delivered good enough performance?
[/QUOTE]

The Jumo 211 was by far obsolete for a fighter engine by 1943; it was simply available in larger numbers when the Ta 154 was planned. The Ta 254 with Jumo 213 (if possible the J version) with its longer metall fuselage (flight stability and fuel) and improved aerodynamics (cockpit section) could have been a fast and fairly economical to build night fighter (cheaper than a Ju 388 or He 219 or Do 335). Performance would be comparable to a P-82 or DH Hornet NF. Like others, Tank and his team knew how to build cutting edge propeller fighters (Ta 152).

 

[Justo Miranda]

The bombing offensives damaged the German oil industry so badly that the future of piston engines was already written in mid-1944. The most serious problem for the Nachtjagd during the winter of 1944/1945 was the low range of the new jet night fighters obtained by the installation of radars in modified Me 262 and Ar 234 airplanes, the space needed for the installation of a radar operator meant sacrificing space to carry more fuel, there were plans to lengthen the fuselage of the Me 262, but there was no time or resources to do so.

 

[Basil]

The bombing offensives damaged the German oil industry so badly that the future of piston engines was already written in mid-1944.

Right. Therefore it is not unreasonable that this class of piston engines would have been replaced by turboprop engines like the DB 021 for some applications as soon they would have been available with the advantage of reduction in required man-hours for production compared to a high end piston engine and no need for high octane fuel. With its "Peterle" project, Focke Wulf already played with the idea of using a turboprop for a fighter aircraft. Although for some long range and high altitude nightfighting missions piston engines would still have had their place.

 

[spicmart]

I thought with Jumo 213E and up the Ta 154/254 delivered good enough performance?

The Jumo 211 was by far obsolete for a fighter engine by 1943; it was simply available in larger numbers when the Ta 154 was planned. The Ta 254 with Jumo 213 (if possible the J version) with its longer metall fuselage (flight stability and fuel) and improved aerodynamics (cockpit section) could have been a fast and fairly economical to build night fighter (cheaper than a Ju 388 or He 219 or Do 335). Performance would be comparable to a P-82 or DH Hornet NF. Like others, Tank and his team knew how to build cutting edge propeller fighters (Ta 152).
[/QUOTE]
Small nitpick: the raised cockpit improved pilot vision a lot but also caused a bit more drag.

 

[tomo pauk]

Right. Therefore it is not unreasonable that this class of piston engines would have been replaced by turboprop engines like the DB 021 for some applications as soon they would have been available with the advantage of reduction in required man-hours for production compared to a high end piston engine and no need for high octane fuel. With its "Peterle" project, Focke Wulf already played with the idea of using a turboprop for a fighter aircraft. Although for some long range and high altitude nightfighting missions piston engines would still have had their place.

Is there a good reason to make turboprops on the fighters instead 'pure' jet engines?

 

[Basil]

Is there a good reason to make turboprops on the fighters instead 'pure' jet engines?

Shorter take off / landings & longer endurance; both important for nightfighters.

 

[tomo pauk]

Shorter take off / landings & longer endurance; both important for nightfighters.

Ah, so it is 'night fighters', not 'fighters'.