One of my favourite automotive words is not heard very often. Ready?
Bisiluro, or bi siluro, “twin torpedo” in Italian, is a type of vehicle where engine and driver are side-by-side.
Before we get into it, 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 (but to respect it, I’ll need to see results thankyouverymuch.)
Why would you design a vehicle around its mechanicals and not around the driver? Speed. What’s a sure-fire way to make any vehicle faster? Reduce drag.
With an eye toward less surface area (and less drag) the bisiluro mechanical layout is most similar to a motorcycle’s, I suppose…with a number of not-perfect workarounds to put wheels into motion.
How fast? In 1948-1949, the very first bisiluro designs by Piero Taruffi were reaching 210 km/h (130 mph) with as little as 50 horsepower.
One of the first bisiluro designs, the TARF II, during a speed run. TARF I had no vertical fins on either side and looked more like a pod racer. (If you haven't made the connection yet between cars like this and fantasy spacecraft designs depicted in popular media: yes, George Lucas is a huge car nerd.)
Looking spectacular though more conventional, the Nardi's bisiluro layout is so striking that it is preserved in a museum…the Leonardo (da Vinci) Interactive Museum in Florence, Italy. Did I mention it also had an air brake? • via melvinresidence.blogspot.com
If you want such a vehicle to move, there will be 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? Where does the fuel tank sit? Is it stable at speed? Or, as drivers reported in period (of the later 1955 24 Hours of Le Mans-entered Nardi Bisiluro)…does it become less stable the faster you go?
Does the wake from a passing vehicle cause it to blow itself off the road?
Ok, look, we’re workshopping this…
(Bisiluros are bad, but not terrible: Google “flying Mercedes-Benz at Le Mans” or, in no relation to this Nardi’s race: “…1955 Le Mans disaster”.)
So there’s that. Must I be wired differently to think all of the above is still A Very Good Idea?
In the U.S. where race cars turn left and tracks are much shorter, yeah, putting the engine beside the driver is an awesome idea: ever hear of Supermodifieds? Turn this sumbitch up:
A Supermodified roaring through the legendary 1/2 mile oval, Bristol Motor Speedway.
Supermodifieds are the homebuilt evolution of more than one professional, high-dollar attempt at winning the Indianapolis 500. The Smokey Yunick Capsule Car was a failure, but the Pratt & Whitney STP-Paxton turbine car, “Silent Sam”, nearly won the 1967 race but for a late mechanical failure. Silent Sam is enjoying its retirement in the National Museum of American History, as it should be.
A year later, the 1968 Shelby Turbine Indy car adopted a similar layout, built from a Lotus 56 single seater chassis.
Though properly impressive, these U.S. machines aren’t strictly bisiluro machines because the bodywork isn’t symmetrical, arranged in a more distinct twin boom where the driver is sat opposite the engine.
A bisiluro is often closer to a catamaran in appearance, whereas other driver-beside-engine machines are packaged inside a single hull. Sorry, Palatov, them’s my rules.
OSI Silver Fox • via Officina Stampaggio Industriale
Now, we get to the Silver Fox. When OSI, or Officina Stampaggio Industriale SpA, revisited the bisiluro layout in 1967, it decided to be more ambitious than past single-function record and race cars: the Silver Fox would seat two passengers, linked by a wide and largely unusable interior.
And…uh…drive out on the road with the regulars…
Where to put the engine? Behind the passenger seat.
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