Extra downforce, reduced drag. Are fan cars like the T.50 and Spéirling the future of aerodynamics?
A car’s aerodynamics is obviously greatly important when it comes to overall performance, whether that be measured in lap times around a twisty circuit or in drag times on a straight-line run. A car’s aero determines how slippery it can be at high speeds, cutting through the air like a knife, as well as determine how well a car can stick to the ground whilst navigating tight and testing corners.
High-performance cars use all kinds of tricks to achieve both high-speed slipperiness and cornering downforce. The Zenvo TSR-S has a large rear wing that tilts left and right as it corners, various electric cars now lack wing mirrors and instead have much smaller cameras on the side to reduce drag and the Aston Martin Valkyrie’s underbody is essentially hollow, leaving a huge gap under the car for air to be channelled to created downforce.
We’re here to talk about a specific aerodynamics trick. The fan.
Pioneered by Gordon Murray, the fan has multiple purposes. While it’s easy to assume that its only job is to literally suck the car to the road, its functionality has evolved past that. In Murray’s latest fan car, the T.50, the large 400mm fan garishly situated at the rear of the car no longer only acts as a glorified vacuum cleaner, as it once did in the famous Brabham BT46 F1 car.
The T.50’s fan aims to do two things; reduce drag at high speeds and increase downforce at lower speeds. At high speeds, the spoiler will reduce its angle, the diffuser vents underneath the car will close and the fan will revolve at high speeds to throw choppy air above and below the car out of the back which will create a “virtual longtail”. The air pocket at the back is said to reduce drag by around 12.5% thanks to essentially extending the length of the car.
At lower speeds, the diffuser vents open and the fan sucks turbulence out from underneath the car, better attaching the boundary layer of air to the bottom of the car and therefore creating superior downforce than what you would get without a fan.
Now, the fan is by no means a new idea as it was first used in the BT46 F1 car and was so disruptive that it was taken out of use after just one race (which it won), despite the FIA saying it would be allowed for the remainder of the season. The reason for this was that Brabham-owner Bernie Ecclestone was afraid it was upsetting the Formula One Constructors’ Association, which Ecclestone wanted to appease to further his career.
Later on, the McLaren F1, known as one of the greatest performance cars ever to be made, had two small 140mm fans hidden under the car. These fans effectively did what the T.50 does now when driving at lower speeds but obviously, it didn’t achieve the same kind of drastic results. Still, these two fans gave the McLaren F1 an extra 5% in downforce and 2% reduction in drag, as revealed by Gordon Murray whilst talking to Harry Metcalfe on “Harry’s garage”.
Now, moving away from Gordon Murray, the man with the apparent monopoly on fan car technology, a new fighter enters the fray. A small, 5-year-old British company called McMurtry has produced a fan car themselves.
It’s called the Spéirling, which means ‘thunderstorm’ in Irish, and although it looks like a car designed for motorsport, it hasn’t been made for any particular race series but rather it is part of McMurtry’s vision to create the ultimate road-legal race car.
The Spéirling is all-electric and described to be able to generate 500kg of downforce ‘on demand’ which apparently includes at a standstill. This likely helps the car achieve its bonkers acceleration feat 0-186mph in under 9 seconds. And if you’re wondering how a few blades that spin around could even help achieve such a thing, just consider that the 60 kW fan produces noise of up to 120 dB when on, which is indicative of just how powerful these fans are.
Will we be seeing more fan cars in the coming years? Could we see one of the big players such as McLaren or Lamborghini adopt the technology? Time will tell!
Let us know your thoughts, in the comments below.
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