Projet F or Projet AP

Project F (also known as Projet AP) was to have been the definitive middle range Citroën and was conceived in four versions

base model powered by a bored out to 750cc version of the 2CV flat twin with torsion bar suspension
flat four, air-cooled one litre with torsion bar suspension
1600cc transverse mounted water cooled unit derived from the DS engine with torsion bar suspension
a top of the range model powered by a Wankel rotary engine and fitted with hydropneumatic suspension and powered disc brakes.

Design work started in the early sixties following the decision to abandon Projet C.

While the use of advanced techniques such as front wheel drive and hydropneumatics had been enough to put Citroën at the forefront of automotive technology during the preceding thirty years, it was felt that something new was required if the company were to maintain its reputation. That something was the Wankel rotary engine and a joint venture was set up with NSU to build the powerplants.

In 1963, there were three prototypes:

AP1 with torsion bar suspension and friction dampers mounted in the wheels; powered by the 602 cc Ami 6 engine; 125x14 tyres and weighing 555 kg
AP2 with hydropneumatic suspension; powered by an air-cooled flat four 1130 cc engine derived from Projet C; 135x14 tyres and weighing 610 kg
AP3 with hydropneumatic suspension; powered by a 950 cc engine sourced from Fiat; 135x14 tyres and weighing 640 kg

Flaminio Bertoni was responsible for the body design (which proved to be very unaerodynamic) but unfortunately he died in 1964 leaving newcomer Robert Opron to complete the exercise.

A number of innovations were to be found - this would have been the first hatchback (if one ignores the Traction Commerciale which was intended as a utility vehicle) , the door frames were welded to the roof in much the manner used by the yet to be released Renault 16 and the use of four headlamps behind a glass panel anticipated the SM's styling.

Unfortunately, the Wankel engine proved to be unreliable, thirsty, and very dirty (it would take another forty years until these problems were solved by Mazda), there were problems with body rigidity, the two versions (torsion bar and hydropneumatic) differed in length from one another, the conventionally sprung vehicle suffered too great a variation in ride height between unladen and laden states and there were problems with road holding and handling.

Furthermore, there was a considerable shortfall in refinement when the prototypes were pitted against the C60 prototype.

Right and below - Robert Opron proposed a number of changes to the front end of the car to improve its aerodynamics

Above and below this 1963 sketch by Dargent reveals styling cues that would eventually appear in the Dyane

Below - the Panhard PL17, sold by Citroën dealers, was viewed as a stopgap solution to the lack of an intermediate model.

By the mid sixties though, the need for a product in what was becoming an increasingly popular and profitable market sector had become pressing.

Above - design study by Michel Harmand

Above and below - more design studies by Michel Harmand for the F - the rear wing/roof pillar junction was to be adopted in the SM.

Above and below - the car featured the first iteration of the instrument panel lunule that eventually appeared in the CX

Work on this project had reached an extremely advanced stage when Renault launched the almost identically styled 16 below. Rumours of industrial espionage abounded but were unproved.

To add insult to injury, the technique for welding the roof and door frames had been patented by Renault. Citroën had decided not to patent the process since it did not want its competitors to have any inkling of what they were up to.

This must be seen in the light of Renault's blatant plagiarism of the 2CV with their R4 .

On 14th April 1967, the project was dropped - millions of Francs were written off and work commenced on project G - the GS.

Projet F proved to be a costly exercise for Citroën.

Presses had been ordered from Budd in the USA and had to be paid for.

The failure of this project had ramifications for the company that led to compromises in both the technologies used and in the model range that eventually led to the financial crisis of 1974 and the acquisition of the company by Peugeot.

The torsion bar suspension was eventually fitted to the Oltcit Club/Citroën Axel.

The lion’s share of engineering effort and cost had been absorbed by the development of the rotary engine.

Having decided to abandon F, the company concentrated on the development of the SM and entered into a marriage of convenience with Fiat whose Autobianchi range was sold by Citroën dealers in France, thereby helping to widen the product range.

As mentioned earlier, Project F would have been equipped with a Wankel rotary engine and as part of the test regime for that engine, a couple of hundred hydropneumatically suspended M35 coupés were built for testing by a selected number of high mileage motorists.

The M35 was also as a test bed for the hydraulics employed in Project G which led to the GS.