Messerschmitt Me 321/323, pre- and follow-on projects (ZSO 523)


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28 January 2006
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Have you ever heard about the Zeppelin/SNCASO ZSO 523?

I´ve been trying to find info about it, but it was very hard, all I have is it was a big aircraft with six engines.

SNCASO = french firm (nationalised aviation industry , 1936)
ZSO looks like a merge of Zeppelin and SO. Try SO-523 maybe?
It was a development of the Me 323 Gigant, transfered to Zeppelin and Sud-Ouest,
with an tow of about 95.000 kg, and a payload of 46.800 kg. Span would have been
70,0 m, lenght 40,25m .Regarding the FLUGREVUE article, where I found this 3-view,
too, development of this aircraft reached a very detailed stage, but ended, of course,
when France was freed by the allies in 1944.
Some years ago, I've asked in another forum, if this development was followed in France
after the war, but unfortunately not. Would be nice stuff for my collection ...
Or is there anyone, who has other information ?
Who's interested in the article, just drop a PM, but please be patient for about 3 weeks,
because tomorrow morning my holidays begin !!! . :D :D :D


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Eureka! During WWII, SNCASO and Zeppelin were surely colaborating. Found a wabsite (in an unknwon language, sorry!) but apparently your aircraft is linked to the Me 323 (the monstruous glider Me-321 with six Gnome Rhone 14M). during France occupation, the Germans asked France to produce all their secondary aircrafts (Me-108, Do-24, Ju-52...). They could concentred on fighters and bombers...
look here
This website refers to the same article , as I did (FlugRevue 4.77). No, I can't read it, too,
it's in polish language. But I could try a translation, or at least a summary from the original #
text into english, for those, who can' read german.
It's a good task, while lying on the beach ! ;D
Thanks Jemiba, time to learn polish, take a soda, or a better drink and please send me the article when you get back form the beach.


As an addendum, I'd like to mention another Zeppelin project aparently resulting from the collaboration with SNCSO: a double deck long, distance high-capacity civilian airliner. It's mentioned in the Nowarra Deutsche Lusftstrung, vol. 4. This night I'll post a scan. It's really impressive (big windows on the ceiling..., just to mention one feature)
Here's the translation of the FlugRevue article about the ZSO 523.
Perhaps one of our native english speakers could give a correction ?


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Hi all,
We, all, know the ME 321 and ME 323.
I have few on the ZEPPELIN:SNCASO ME 523
But I 've nothing on the project Messerscchmitt Zeppelin me 423 !
Could someone give something on this project ?
I thank you, if you could answer
In "Willy Messerschmitt - Pionier der Luftfahrt und des Leichtbaus" two Messerschmitt
projects, P.1202 for a heavy and 1203 for a medium transport are mentioned, both based
on the Me 323. May there be some connections ?
Hans-Peter Dabrowski, in the chapter "Die Abteilung Flugzeugbau der Luftschiffbau Zeppelin GMBH 1942 bis 1945" from the book "Zeppelins Flieger", page 252, mentions the Z Me 423 as included in a report dated 3rd September 1943 , with no additional data. Maybe it was the Z Me 323 H with six BMW 801 ("8801-TP-Motoren" in the original), as Walter Stender, the chief proving designer, intended to do.

In the book Jemiba mentioned, nothing more to add, but I have never heard about Messerschmitt projects beyond 1112. Can you please tell in which page you have found it?
Sorry, should have made this clearer, I think :
The P.1202 was proposed post-war, but was closely based on the
Me 323. So my thoughts just were, if it could have been in fact a
"recycled" project from war times ?
(page 367)


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Thanks you for your answers.

Now I have a new question ! ,as Wurger, I stop Me projects at P1112
and you speak of after war projects P1202 & 1203 with a three views. I don't know.
Very well, I learn.
Well, but after the war I only know M.B.B. and no projects in the 1200 serie ?

In an other hand, In these rubrique, page 38, dated 08.13.2006, a long time ago
I found a three views of the ZSO 523 and also a three views of a big Zeppelin pusher
what is the reference of this studie ?

Excuse me for this questions !!
I'll send you the projects list from the mentioned book and the articles about
the ZSO 523 and the airliner this evening.

MBB was actually founded as late as 1969 and Messerschmitt developed quite
a lot of designs in the meantime, although not only aircraft ! His most famous
non-aircraft probably was this :
(photo from wikipedia)


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Thanks. i'm waiting...
I'm an old man, I remenber that I saw this Messerschmitt ' car.
hi Jemiba.
i send you a document
Jemiba said:
I'll send you the projects list from the mentioned book and the articles about
the ZSO 523 and the airliner this evening.

MBB was actually founded as late as 1969 and Messerschmitt developed quite
a lot of designs in the meantime, although not only aircraft ! His most famous
non-aircraft probably was this :
(photo from wikipedia)

Except the Kabinenroller wasn't Willie's design, it was developed by Fritz Fend
from his earlier invalid carriages and Flitzer.

Messerschmitt suggested refinements to Fend's design that led to the Messerschmitt
produced vehicle being larger than the original, however the design was primarily the
work of Fend. Fend had worked at Messerschmitt during the war.

dear joncarrfarrey.
Very interesting, I've never see the first model !
Thanks. Bye
There is a bit more information on the ZSO.523 in the book Nieuport 1909-1950 (Docavia no.38) by Rosenthal, Marchand et al.
The study was done by a team led by Pillon and Robin. This was a team of former Nieuport engineers, integrated into the SNCASO in Cannes in 1941. The team was moved from Cannes to Paris and Issy-les-Moulineaux in late 1943, then they started to work on the Zeppelin project under threat of being sent to Germany.
A wooden mockup was built in the Levasseur factory (the book has a picture of the mockup). The prototype should have been produced by Zeppelin in Friedrichshafen, and the SNCASO would have participated in the series production.
It is said that the study was made at the lowest possible pace, while the team was secretly studying its own military projects. After the war, the Issy-les-Moulineaux team was transferred to the SNCAC, and one of these wartime secret studies became the SNCAC NC.1070 two-engine naval torpedo bomber. Experience gathered with the ZSO.523 project was used for the NC.211 Cormoran four-engine cargo, which indeed shows some similarity to the Gigant design.
Me 323 with Alfa engines?
I received a couple of days ago a mail from a friend, quoting another mail from a fan of Alfa Romeo aircraft engines. This guy wrote of an hypothetical Me 323 V15 (or Me 323C) flown in 1942 with four Alfa 135 engines and the friend of mine asked me if I have any information about that prototype.
Personally I know that the Me 323C (originally Me 321C Gigant) was to have been a motorized glider rather than a fully-fledged powered transport. The project studies considered several power plants with four or six engines (BMW 801, BMW-Bramo 132R -itself a version of the Pratt & Whitney Hornet-B-, Jumo 211and Gnome-et-Rhône 14N). Finally, the latter was choosen (with four units per aircraft), removing all GR 14N 48/49 from Bloch 175 airframes.
According to my sources, Me 323 V1 was the prototype for the four-engined Me 323C, but serie production was only in the Me 323E and F six-engined versions.
Billy Green's encyclopaedia on German warplanes mentions the Me 323 V15 as an attempt to improve further the defensive capabilities of the Gigant, with no mentions of Alfa Romeo (AR)135 RC.32 or RC.35 Perseo engines. According to Green, further developments are V16 (Me 323F) with six Jumo 211R and V17 (Me 323G) with six GR.14R.
Anyone of you, friends, have something to tell my friend about this matter?
I found a list of Me 323 projects in "Willy Messerschmitt - Pionier der Luftfahrt und des Leichtbaues" by Hans Ebert/Johann B Kaiser/Klaus Peters, Bernard & Graefe Verlag, 1992. In this book, the authors claim several engines were tested on Me 323 prototypes, among them Jumo 211 and Alfa Romeo (p.227).

To make matters even more exciting, Prof. Lösch and Dipl.-Ing Pauker of the technical univerity in Vienna suggested the use of a steamturbine in the Me 321. Prof. Adolf Baeumker of the Reichsluftfahrtministerium took over development of this idea in 1941, but after testing the Me 321 (<edit>*without* the steamturbine</edit>), the idea was shelved. In 1942, Woldemar Voigt proposed fitting the Me 321 with twelve Argus As 014 300 kgf pulsejets, or twenty-four smaller 150 kgf pulsejets. With rocket-assisted take-off. That idea never took off either (p.226).


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Then there was a connection with Me 323 and ZSO 523 ???
Well, could be interesting find more about projects inside development of Me-323 to ZSO 523 ! ::)
The issue of Alfa 135 flown on a prototype of the Me-321 was uncovered by my friend Gianni Cattaneo in 2005. The news is contained in the extended "curriculum vitae" of Ing. Roberto Amadi, who worked for Alfa from 1937 to after the war. His work was to assist airframe companies in integrating Alfa engines in their designs and then test the results. In 1942, Amadi writes, Willy Messerchmitt came at Alfa and bought a series of Alfa 135 for his Gigant. Amadi did a series of trip to Berlin (RLM) and to Leipheim, a test airport near Ulm, with the techicians working with him. Later in 1942, after the engines had been installed on the Me-321, Amadi did a test flight with Alfa and Messerschmitt technicians. Some minutes in flight, the test had to be interrupted because the airstream produced by the propellers tored apart the fabric revestment of the wing. The fragments flew on the tail controls, hampering the pilot's ability to manouver, The aircraft nevertheless was able to come back and land. That's all I know. I know moreover that Fabio Morlacchi, who is doing extensive research on Alfa aeronautical activities, has uncovered some documents, so he said during a conference a couple of months ago. He is writing a book on Alfa aero engines.
Thank Sky,
I think that can be a definitive word on the matter!

The zso 523 model !


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There is a huge (17 pages!) article on the ZSO 523 Super Gigant in the German Luftfahrt History N°8. It is packed with photos and drawings (mostly from the RLM reference documents) which has to be the definitive source. I'm only posting a few here, without captions or technical details, and in medium-sized quality, but for anyone interested in German (and French) projects, this is a must. It also contains a similarly packed article on the Junkers EF 94/Ju 322 Mammut.


More information here:


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More pics:


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SNCASO = Société de Constructions Aéronautiques du Sud-Ouest

A November 1936 combination of: Blériot, Bloch, S.A.S.O, U.C.A, S.A.B., Lioré & Olivier.

in an article about Messerschmitt Me.321 & Me.323 there is a strange drawing to "Me.261 w" with
Me.321,and I don't know what was this Me.261,a glider ?.

Flugzeug Classic 7/2008


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This was the first step to Me 321/323 . this led to a "Me 263", and later the designation became Me321 ...
Excellent my dear Richard,

thank you very much.
richard said:
This was the first step to Me 321/323 . this led to a "Me 263", and later the designation became Me321 ...

My dear Richard,

I forget to ask you,do you have a more info or drawings to Me.261 & Me.263 (as a gliders) ?.
Thank you my dear Richard,

and here is a very small info about Me.261 and Me.263 gliders.


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hesham said:
....and here is a very small info about Me.261 and Me.263 gliders.

... from HP. Dabrowski "Messerschmit Me 321/323 - Giants Of The Luftwaffe", Schiffer Publishing, BTW,
interesting additional reading about that type. ;)
Thank you my dear Jemiba,

and here is early prototype drawing to Me.321,differed from the production one.


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Got "Deutsche Lastensegler" by Heint Mankau and Peter Petrick for a bargain price this
week, interesting compendium of the German tarnsport and assault gliders. It contains a
drawing of the Zeppelin Messerschmitt ZMe 323G, a Me 323 development delegated
to Zeppelin, which would have been powered by six GR 14R engines and with the cockpit
located further forward, clearly the precursor to the ZSO 523.


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Firts time that my old eyes see this one...!
Thanks for sharing Jens.
Wasn't quite sure, where to post it. In the Messerschmitt thread, or the one about Zeppelin projects ? But I'm
pretty sure, that it's the "missing link" between the Me 323 and the ZSO 523.

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