Development of 901 Convertible, Prototyp 13360 (built 1964)
Re the 901 Convertible - Prototyp Chassis 13360 - I recently read an interesting article by German Journalist Wolfgang Blaube who posted it on a swiss website.
http://www.zwischengas.com/de/FT/fah...?teaserindex=1
I first thought that they will repeat infos I read elsewhere (plus a few faults..) but actually it confirms many infos published first by Aichele's book published 20 years ago. Aichele description is still the most detailed literature about this theme.
BUT the interesting part is however that this new article reports a few infos unknown to me and - I beleive until today - have been never detailed in any literature about the 901/902 development. It cites several employees of Reutter and Porsche, some have been interviewed by Aichele before, some never.
Here is the text freely translated from german to english (I shortened it a bit and corrected google translator).
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The mysterious forerunner - the 901 Convertible of 1964 (and his successful successors).
« What is so special about the 1964 901 ancestor of the fully open 911's, which came finally on sale in 1982?
Why it was not immediately produced? And did 13360 had an influence to the 911 Targa, the variant which bridges the long convertible-absent Porsche time period ?".
Before it comes to these above issues, the history of the open-air Porsche 911 is often told like this: When the factory developed the 356 successor 901 in the early 60ies, in the US all convertibles were treated to be banned by future safety laws, initiated by the influential consumer advocate Ralph Nader. In response, Porsche anticipated the full convertible ban in their core U.S. market: the legacy of the successful 356 Cabriolet would receive stable roll bars and became the 911 Targa - the first security convertible in the world.
Sounds as logical as romantic. But it is wrong.
1st: Neither Nader nor anyone else at that time (early 60ies) talked about a possible convertible ban.
2nd: in the last years of 356 production, the sale of 356 Cabriolet was so unsuccessful that the actual development of the 901 took place without any consideration of an open version.
3rd: the official factory version of rollover protection for an open 901 lead them to a Targa bar is wrong and that it rather was the embarrassing solution of a technical compromise.
Words that provoke and proofs are needed. Reboot for the real story:
Upheaval and cost pressure for Porsche
When Porsche outlined its next-generation sports cars in the late fifties, the company was in transition. The need for improvement in performance and road behavior required a further position away from the usual Volkswagen-based technology.
At the same time the growing influence of the third-generation Porsche brought fresh air - and unrest among the old grandees. Ferdinand Alexander "Butzi" Porsche is named Head of Styling while Erwin Komenda is relegated to second in line, even Komenda was -since the late 30ies- Chief of Design&Konstruction bureau. Later Butzi’s cousin, Ferdinand Piëch replaced long-time race director Huschke von Hanstein. This upheaval in the house of Porsche produced fierce arguments over how the 356 heritage car -the 901- should look and what technology would be fitted to the new car.
The 901 is also more demanding during the design phase and therefore much more expensive to develop. Increasingly, questions were posed which 901 parts could be produced less expensive all while schedules were getting tighter.
Beloved 356 Cabriolet ?
In 1962, radical cost cutting for the 901 development were defined - including the courageous decision to kill the open 901 variant completely. Reason for this were also the sharp decline of sales of open 356’s. In 1960, 356 convertible sales were 41.6 percent of total production, in 1961 they fell to 27.2 percent and 1962 fell further down to 19.8 percent, further decline was expected. In 1964, -the last full 356-year- only 1745 of a total of 10312 cars built were convertibles: a meager 16.9 percent of total number of units.
And, in a clear contradiction to current literature, the often cited status of the «coveted 356 Cabriolet » can be now questioned : Often it is said, open 356 were a 35 percent of sales. But this reflects only the final year of 1965, which ended in September. From April 1965 on, the 911/912 Coupe were already off the production line and by end of 1965, 588 356 Convertible are built but only 1100 356 Coupes and also combined 9558 units of the new 911/912 Coupe's. In other words, in 1965, only one of twenty Porsche's built were open cars.
Conceptional abandon of an open 901 version
Above production/sale numbers speak for themselves. Nevertheless, the total abandonment of an open version of the 901 sounds today incredible. Especially why reasons were never officially transmitted. But the memory of some 901 body developer is intact. "In addition to the Coupe there was no other body structure part of a discussion," says Sylvester von Sass (81), responsable as a designer for the 901’s doors and hood at Porsche’s prototyp builder, Reutter. Its predecessor, the enthusiastic convertible fan Reinhard Schmädicke (79), underpins ". Butzi told me quite clearly that no Cabriolet is planned." And Erwin Komenda put it even more clearly by saying that he was "fundamentally opposed to any unnecessary hole in the body."
Nevertheless, in the second half of 1963, there were several conceptual plans created for a fresh-air-901. For cost reasons most use the Coupe’s doors including their window frames. But no decision to actually built such a car were made.
The fact that there was finally deciced to build one - a decision made in June 1964 , nine months after the debut of the 901 at the IAA - was due to the marketing people. Ferry Porsche's nephew Harald Wagner (now 90), 1954-1988 Head of Sales Germany and the largest convertible supporter had not given up: finally, evidence for a new convertible sales boom are reported from the USA.
The first 901 Cabrio built in 1964
Karmann immediately begins building a prototype.
On 2 September 1964, the Porsche's factory production planning for the period 1964 to end of 1965 is defined: 5000 closed 901 and 902 Coupe and 1000 «open cars». Eight days later, on September 10th, Karmann provides the first convertible prototype, chassis number 13360 to Porsche's testing department, delivered without any roof construction.
This was planned to be done in Zuffenhausen by Porsche convertible specialist Gerhard Schröder. He worked before in Cologne at Convertible manufacturer Karl German and after 1952 at Ramseier (Body work Worblaufen, Switzerland). Shortly afterwards he landed at Karmann where he was responsible for the VW Karmann Ghia Convertible as well as the Beetle convertible by Karmann. Finally, in 1956 he joined Porsche.
There were neccessary changes to be made that would make the 901 Coupe enough rigid for a convertible. For Wolfgang Eyb (89), then head of the 901’s body structure, it was a hopeless plan: "If a car will be configured in an open and in fixed head version" you "build only the open version and then the closed version is based on it. Since the basic structure of the 901 was provided for only a Coupe, we then should have done it the other way around - which was impossible. Stiffness of the 901 convertible was always inadequate".
Eugen Kolb (77), a then young engineer in Schroeder's team, gives an idea of the dilemma: "We even called the designer Fritz Martin back from the retirement and let him draw and calculate for two weeks.
At the end he said: "The open 901, you can forget. After many desperate stiffening tests at the factory we finally tried an idea that was thought out in 1963 but initially hacked as the team felt it was the "aesthetic’s worst case" but technically the only realistic compromise: the "firmly welded roll cage"."
