1973 Citroen SM - 1:18 Diecast Model

  • £249.95


 

Citroen SM - technical innovations

  • Speed sensitive power steering
  • Advanced aerodynamics
  • Carbon fibre wheels
  • Rain sensing wipers
  • Turning headlamps

Citroën purchased Maserati in 1968 with the intention of harnessing Maserati's high-performance engine technology to produce a true Gran Turismo car, combining the sophisticated Citroën suspension with a Maserati V6. The result was the Citroën SM, first shown at the Geneva Motor Show in March 1970. It went on sale in France in September of that year as Citroën's flagship vehicle, competing with other high-performance GTs of the time.

The SM Introduced many unusual and innovative features, some of which are only just becoming commonplace on cars of today.It borrowed heavily from the innovations introduced on the DS, by including hydro-pneumatic (oleo pneumatic) self-leveling suspension, and self-leveling lights that swiveled with the steering.

The SM was Citroën's way of demonstrating just how much power and performance could be accommodated in a front-wheel drive design with minimal torque steer - where excessive steering feedback impacts control of the vehicle. The solution adopted was to offer no road feedback at all - the driver simply pointed and went regardless of what the driven wheels were experiencing. Hitting a pothole at high speed would not turn the steering wheel in the driver's hands.

This new type of variable assist power steering, albeit with some feel reintroduced has since become widespread in most vehicles today. DIRAVI as it was called, provided great assistance to the driver when parking, but little assistance at motorway speeds. The system adjusts the hydraulic pressure on the steering centering cam according to vehicle speed so that the amount of steering feel remained almost constant at any speed, counteracting the tendency of manual and ordinary power assisted steering to feel light at high speed. Thus the car turns easily at low speed, emphasized by high gearing given two turns lock-lock, and relatively more effort is required at higher speed. In addition, if the driver released the steering wheel, then it would return back to the straight ahead position. It was geared for minimal steering input - with 2 turns from lock to lock, often described as like a go kart. Many contemporary reviewers remarked that this system would take at least 50 miles of driving to become familiar with it, but once the driver is accustomed to the system, then traditional steering feels old-fashioned.

The wiper mechanism when on the "low speed" setting was 'sensitive' to rain by measuring the current needed to drive the wiper motor.

The steering column could be adjusted for both height and reach.

The braking system, adapted from the DS, employs disc brakes at all four corners (the DS has drums at the rear), with the front brakes being inboard, and cooled via large ducts on the front underside of the car. The hydraulic braking pressure front to rear balance is self-adjusting according to the weight in the rear of the car, so on hard braking the entire car lowers evenly.

Standard wheels are steel with stainless trims, but for the rigors of off-road racing, Michelin developed a unique solution - a lightweight carbon-reinforced resin wheel, which became a factory fitted option. These weighed less than half the standard wheels and were decades in advance of similar applications.

Like the DS, the SM had covered rear-wheel and seen from above, it was wider at the front than at the rear. This made it unusually aerodynamic for its era, with a low drag coefficient of just 0.26. The ventilation intake was located in a "neutral" area on the hood, which makes the ventilator fan regulate the interior ventilation at all road speeds.

In 1970, it was a car of the future and the fastest front-wheel-drive car, with a factory-quoted top speed of 220 km/h (140 mph), and independent tests achieving as much as 235 km/h (146 mph). It was an example of the car as a symbol of optimism and progressive technology, similar to the SM's contemporary, the Concorde aircraft.

The SM's design placed eleventh on Automobile Magazine's 2005 "100 Coolest Cars" listing.

Material: Metal
Scale: 1:18