OSI Silver Fox


One of my favourite automotive words is not heard very often.  Bisiluro, or "Bi Siluro"—"twin torpedo" in Italian—is a type of vehicle where the engine and driver are side-by-side. 

Although they look spectacular, like two Bonneville belly tankers (or fat Sharpies) linked in the middle, the bisiluro layout is so striking that one of the first has been preserved in a museum. 

The Leonardo Da Vinci Museum in Milan, Italy.

If you want such a vehicle to move, however, there will be a few challenges. How do you get the power from the offset engine to the wheels? Where do you mount the engine, for that matter? Is there room for passengers? Is it stable at speed? Where does the fuel tank sit? 

I'll tell you one thing: it's a layout that puts engineering theory above the needs of a driver. That's an attribute I adore.


With a goal of less surface area—and less drag—the mechanical layout tends to be similar to a motorcycle. Think of it: rider on one side, engine on the other. 

Why would you design a vehicle around its mechanicals and not around the driver? Speed. 

One of the first bisiluro designs, the Tarf 2, during a speed run.

One of the first bisiluro designs, the Tarf 2, during a speed run.

How fast? with just 50 horsepower, the very first bisiluro design hit 210 km/h (130 mph)…in 1948.

But when OSI, or Officina Stampaggio Industriale SpA, revisited the bisiluro layout in 1967, they decided to be a little more ambitious than single-function record cars. The Silver Fox would seat two passengers, linked by a wide and largely unusable interior. 

Where to put the engine? Behind the passenger seat. Fuel tank? Up front. Differential? In a wing-shaped pod between the two wheels.

The spoiler between the front wheels was used for the steering linkage, and was adjustable to different downforce levels. The centre spoiler—the cabin—gave stability and had adjustable elements to aid downforce.

Maybe I'm wired incorrectly, but this layout, along with the Delta Wing, are very attractive to my eyes.

Oh, speed. Well, from a 1-Litre Renault-Alpine 4-cylinder engine, top speed was a lofty 240 km/h (155 mph.)


Side impact standards be damned, the car debuted at the 1967 Turin Motor Show and was slated to compete at Le Mans the following year. Financial difficulties hit OSI and it never did.

It has resurfaced since, at various car shows.

I like to imagine the bisiluro concept resurrected somehow, but with in-wheel electric motors and a smartly-packaged battery array.

The Silver Fox isn't the best-known OSI, however, and the company is known for having produced some very pretty designs.

But that's a story for another day.

Sources / Recommended reading