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With a ‘U-Boat’ to Tokyo. 1995. BMW show car, Z21

“So we had arrived with our ‘U boat’ in Tokyo, though at the moment it was not to be seen, just wooden boards, grey stones, rolls of carpet and an almost finished framework that would soon become our presentation stand.
Although we were in Tokyo the language to be heard, at least locally, was not Japanese but German and these mostly Bavarian voices were drinking not the local drinks or even coca-cola but coffee made in machines that, like every thing else on the stand had also made the long journey from Southern Germany to Japan.

I was feeling tired despite having had the business class comfort on the SAS flight to Tokyo and as Agnes, our exhibition project leader, moved away to talk to the men responsible for building our stand, I sat down on a pile of grey slate stones, that would later become a floor and accessed the progress not only of our stand but also the the others around us, and as it was my first trip to Tokyo, I was interested to see the local people at work.

No matter where I looked the sights and sounds were similar, building sites, some slightly more finished than the others, a selection of automotive corporate identities all specially built, being put up to convey a corporate message, if only for two weeks.

I was soon leaving the exhibition halls of with a Japanese BMW marketing guy and as he drove me the sixty kilometers into Tokyo he explained one of the problems they currently had, fitting four sets of golf bags in t the trunk of a seven series….. but his voice faded into my thoughts and as they were stronger, I no longer heard his words and using some sort of programmed response answered his questions but I was still in the exhibition halls, full of expectation for the weeks ahead and the world premier.

The Maratani hotel was to be my home for the next couple of days and thankfully the time passed quickly, sights seeing, visiting companies and experiencing Japanese cooking. Tokyo itself is simply so full of people and is so busy that I began to wonder how any body can live here yet despite the mass of people everything except the traffic runs smoothly and efficiently.

Almost three days later we checked out of our hotel. I had joined up with my Boss, Klaus Kapitza and we travelled, sitting cramped in the back of a small taxi, out to the exhibition centre and our huge marble palace, the hotel new Otanni which lay within walking distance of the presentation halls. Young, elegantly dressed girls stood at the entrances, bowing politely as one walked in.

I checked in as quickly as possible and then made my way out of the hotel across the raised walkways and into the halls. Agnes was still there talking to Barbara, the stand designer, almost as I had left them three days earlier, talking to the builders, but around them the mayhem had become a finished exhibition stand, the carpets and slate stones no longer lay in piles or rolls but were carefully placed on the wooden floors becoming roads and walkways.

I looked into there tired faces and saw despite the sleepless nights a satisfaction, they were almost finished. With pride they showed me over the stand pointing out the problem areas and re-convincing me that the red colour scheme they had chosen for our display was correct after all. I still didn’t agree but that was no longer important. As the evening came more and more life flowed into the halls, the preparations for the press days were taking place. On every stand builders were being replaced by pretty Japanese girls practicing their presentations and the just finished platforms were now occupied by the main exhibition pieces, automobiles from every manufacturer throughout the world.

On our stand I suddenly heard familiar voices and was soon being hugged by Joanne and Niki, two dancers, part of our group there, like myself, to present our wares, our ‘U Boat’. Joanne and Niki were members of a group of dancers who were to put on a show, which had been prepared in Munich, to show the lifestyle surrounding our car. Although they were feeling extremely tired from there long trip the choreographer decided they needed a rehearsal. As I listened to the first beats of Joe Cockers, summer in the city, my thoughts wondered, this time not to the opening in less than two days time but to the past, back in Munich and the BMW ‘Just 4/2′.”

Rehearsal for Life Style presentation

In the summer of 94 within the walls of BMW’s top secret think tank the BMW Technic GmbH a presentation was being made to the head of the board. Eight potential car concepts were being considered to become BMW Technics next project.
( The first 5 years of BMW Technic had produced the Z1, a 2 seat roadster which went into production. The E1, an electric car concept, fully engineered in typical BMW Technic manner and Z13 which I I shall refer to in another post)



My Z21, a crossover motorbike / fun car concept was one of the eight potential project idea’s.
Dr Reitzle didn’t choose my concept then but another fascinating idea. My boss, Klaus Kapitza, ZTs head, Mario Theissen and other members of the 140 head strong company felt that my concept had potential and I was given a small budget and man power to take the ideas further. The project was to remain top secret and ran under the name of a ‘U Boat’, a submarine project, hidden from sight.



Over the following 4 months I engineered, constructed, designed and helped my 3 model makers build a wooden, design / package seating buck.

Project start: Building the Seating Buck.

As the project progressed it developed an amazing dynamic and more and more departments became involved in making this concept model as good as possible and making sure that my technical concept was correct. Dr Mario Theissen (later to become BMW motor sport head ) took over the head of BMW Technic and was equally fascinated and supportive with the project. Theissen gave the project another aspect, supporting our ideas to produce a complete life style range of products including clothes and headwear.

Seating Buck frame is finished and painted.

In November, after a final weekend of nonstop work the concept was presented as a surprise to Dr Reitzle. This time the concept was completely understood and during this meeting it was decided that this concept should be built as a running prototype and be shown, a year later, at the Tokyo Motor show. It was also decided that a clothing collection be produced which was later used as part of the lifestyle presentation in Tokyo.

 Projects like this cost a lot of money especially as BMW and the BMW Technic didn’t build empty shells but fully engineered prototypes.

Concept Presentation. I am sitting in the painted wooden Just 4/2. In the Background is the Z13 Concept car I design in 1993

A kick off budget of several million marks was approved immediately so that the project could start and we kicked off with a ‘get to know each other meeting’ in January, 1995.

 Few words can describe what really goes on in such a project. On the one side it was my baby, my idea, almost a dream but on the other side was a down to earth realism. The job; 10 months to design, engineer and build a fully running prototype. Now there was a team and each member of the team had their own ideas and technical requirements. So with some heated discussions and soothing words from the Project head, Dr Theissen, we kicked off !

Looking back I would say that the project was to run smoothly with the usual moments of incredible tension. I would fight with my wonderful boss, Klaus Kapitza, to retain the concept while being under pressure the whole time to change it.

 The entire concept, a crossover fun car between a Motorbike and car was based around Aluminum extrusion technology. This technology, as on a motorbike, was completely visible and meant for construction that there was no hiding your engineering behind panels as on a conventional car. 

I had constructed the concept model in the old fashioned way, three extremely complicated views in full size pencil drawings hung on the wall. Now all this information had to be digitalized as the car would be constructed in CATIA, the standard automotive software program.


The first week saw the wooden model on the measuring plate as all the 3 dimensional coordinates were put into the system. 

Most of January was spent on this process but at the same time other work was taking place. The engine was to be the BMW K1200 unit mated to a 5 speed gearbox. A small team including Klaus Gersmann who was heavily involved with Z13, began working on this area. Solutions would eventually be found for all the problems that would arise. You dont just put a bike engine into a car, especially when you are BMW and any sort of engine, engineering, is very serious stuff. The engine was to be seriously modified to optimize torque and a 5 speed VW gearbox was to be the only solution to drive those rear wheels. Later on in the project I followed the testing of the engine on the test beds within BMW Motorbike.



After the first three weeks my original construction was in CAD and a team of engineers began to access and re-engineer my construction. I was continually monitoring this work as I had come up with a lot of subtle solutions that could easily get lost especially as the cars frame was divided into an upper and lower construction group handled by different engineers. This would later cause some problems when I noticed that door flange depth varied between the upper and lower structure by 5mm ( upper 15mm, lower 20mm ) but this too was solved. Of course this structure was being calculated for stiffness and crash and the needed changes, even for the prototypes, were applied to the structural design. 

The final Aluminum extrusion structure would be made up of 19 different profiles. Most were bent in at least one direction.

The first CAD Package drawing produced by construction.

The profiles were produced by Hyrdo aluminum in Denmark. I took several trips to visit the company during the production of these profiles and remain fascinated by this technology. As can be seen in some of the photos the frame was completed using 6 aluminum castings that would hold the spring damper units as well as the gear change.



Before the frame was actually produced we went though a clay model prove out phase. This meant that the engineered frame was modeled in a full size clay model. This was my first chance to see just how the ‘real‘ construction now looked. This process also gave me a small chance to change some areas if I felt the design character was lost. We also now had to fill in the areas between the frame. These small panels would later be made of CFK and add to the cars lightness. Once the clay model was finished moulds were taken of the clay to create the negatives for these parts.


The finished ‘Prove-out’ clay model

Hydro Aluminium wanted to deliver a completed, welded frame but Fritz Schub, head of the workshop, decided it was better to assemble it them selves. This process was not to run as smoothly as hoped but in the end all worked out well. Parallel to these activities all other areas of engineering and construction were taking place.

The almost completed frame.



The door beam opened vertically and took with it a small panel. This panel could also be removed by simply turning 2 quick fasteners and then stowed behind the seats. Wolfram Haug, the engineer responsible for the door engineering also came up with a solution to a problem we hadn’t even thought about. When the door was open, without door panel, it was almost impossible to reach. Wolfram conceived and engineered a fourth pedal, located in the footwell. Due to a simple linkage, pressing it with your left foot lowered the door……

Other areas also showed wonderfully simple mechanical solutions.

Detail of the frame build. The door opening mechanics can be seen

Obviously for a prototype, even one as thought out as this, constructing a new gearbox was out of the question. The VW 5 speed box was mated to the K1200 but being a front wheel drive box meant the changing mechanism came out of the rear of the car. The change linkage, runs inside the central middle tube and under the engine. The change quality was remarkable; brilliant engineering!



Underside view of the engine and gearbox in car.

The seats are another masterpiece. Being a crossover car all aspects of the interior were open to the elements and had to be waterproof. All components also had to be light but still fulfill crash regulations. We used an external aerospace company for this part of the project. I designed the seats, once again in the old way…….my 3, hand drawn full size views plus some design sketches were given to the company. They engineered and made full size models with I checked at regular intervals. Soon they moved on to taking moulds and building he final seats. Stunning, double skinned CFK shells were manufactured. The seats were adjusted by visible, aluminium knobs. Each finished seat weighed 7.4 Kilos!


The Interior: Photo Jesse Alexander.

The months passed and the project took more and more form. 
All suspension components were finished, dry fitted and tested. Infact we had the car finished and sitting on its wheels by the end of September. Once everything was tested it was taken apart again. Body panels were painted, suspension components polished and last minute parts were made such as covers for parts of the engine that didn’t look good enough.

 What I remember most about this project was the buzz that it created with everyone that worked on it. There was a great sense of proudness. The engineers were proud of their mechanical solutions ( which all could be seen) the guy who welded the frame was a maybe a little unhappy about a couple of welds that were not as perfect as he wanted but generally happy . The CFK companies responsible for the panels were proud of their low weight and quality.


Dr Mario Theissen and Klaus Kapitza did everything to make the project a success as did every other member of the team. 

About 2 days before shipment we put the car in a photo studio to produce the press pictures and several days later the car was pushed into its travel box and secured and as the entire team stood around with a glass of procesco the door was closed and sealed.

 Within an hour our ‘U-boat‘ was gone. In a large wooden crate on its way to Tokyo.

34 additional images. Click to enlarge.


9 responses to With a ‘U-Boat’ to Tokyo. 1995. BMW show car, Z21

  1. Every single line a joy to read, Rob.
    Many thanks for sharing this.
    Don’t know whether you’re aware, but CATIA today is my employer after they acquired my company.

  2. I’m starting to realize what a learning journey this site is going to be… I’ve obviously never heard about the car, until now, so the story and the pics are be interesting in their own right – but then it is enlightening to get a few glimpses into the design process of such a unique and good-looking build. Thanks for sharing this. Very educational.

  3. Yes..the pictures are listed in the order of the project: Starting with the wooden mockup we built to ‘sell’ the project to the board. The clay ‘prove out’ pictures are fairly clear. The blue car in the woods was part of a photo day in Oberpfaffenhoffen when I was allowed to borrow the car for the BMW photo club ( A story in itself ! ) The last 3 B/W images are taken bei the great Jesse Alexander in the Parc de Bagatelle, Paris in 1996. We were invited to show the car along with six other show cars at a Concours E’legance, and 60 remarkable vintage cars. Last two pictures are the lifestyle present in Tokyo.

  4. On second read of this article – what happened to the car eventually?

  5. The project actually continued late into 1996. It was felt there was a market for such a product
    and several things happened. A potential market volume was presented by marketing based on a production price. Most expensive component was the K1200 engine so variations were looked at.
    Three outside companies, including Pininfarina, Turin and Loades, Coventry ( Jaguar 220 production) produced production plans based on this intended production volume. The car wasn’t actually that expensive to produce.
    Then in late 96 came feed back from BMW NA marketing . ” 0 potential sales predicted “. The final blow.
    We did build two fully running prototypes- one could be on display at BMW Classic in Munich.

  6. It could have been the successor of the Caterhams and I can see it on a comparable level to the KTM X-Bow.
    Track day people in UK would have loved it.

  7. ..at the very beginning of the project we had a Caterham in the studio to compare.
    And though out the development a single seat track version and racing series was part of the considerations…

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