Top Gear drives the DeltaWing

I'm the same size as Lucas Ordóñez. That's what the team is telling me. The team is wrong. I've stood next to Lucas, and he's inches taller. I can barely see over the fiendishly complex carbon steering wheel of the Deltawing but come to the conclusion this might not actually be a bad thing. After all, what my eyes can't see, my brain can't panic about.

Because the Deltawing looks like it can't possibly work. I know it's fast - Lucas and co-driver Gunnar Jeannette drove this thing to fifth place overall at Petit Le Mans right here at Road Atlanta, barely two days ago. I'm sure the physics is sound and am rapidly coming to the conclusion that Ben Bowlby, father of the Deltawing, is nothing less than the messiah of motorsport. I'm sure of these things. But then I elbow and shoulder my way back out of the deep cockpit after my seat fitting, look at it and shake my head. Back to square one.

Photos: Rowan Horncastle

This feature first appeared in Top Gear magazine

The day before the race, the drivers put on Batman costumes for the gridwalk, which tells you a) Deltawing is clearly aware of the visual link, and b) that it doesn't take itself too seriously. Not that it's possible to take yourself seriously when your car looks like a reimagined dragster or some radical Bonneville straight-liner. What it doesn't look anything like is a car designed to go round a track. No, just no. Triangles don't work.

But then Bowlby gives me the full tour, and it's nothing less than riveting. The science that underpins his brainchild is refreshingly easy to understand, at least up to a point. It's all about matching tyre grip to weight distribution. It won't surprise you to learn Deltawing ain't exactly front-heavy, something Bowlby proves by squatting at the nose cone and lifting the front wheels of his 475kg racer off the ground. I try, but fail, then realise that even with a weight distribution of 28/72, there's still 133kg to lift. Bowlby is a lot stronger than he looks.

But I'm getting away from the point here, which is that less weight needs less tyre width, as the forces acting on it are so reduced. So it uses Citroen 2CV-dimension front tyres, each just 100mm wide. It also uses real 2CV front tyres. Michelin is so protective of the technology it's developed here that it will not leave the team with the race rubber, but instead lends them some ancient, heavily treaded 2CV tyres so Deltawing has something to trundle around the paddock on.

So that's the tyres, what of the aerodynamics? "It's very odd," Bowlby tells me. "You think a teardrop is the best way to go, but the dart shape makes a very rearward centre of drag - even further back than the centre of mass - so you have a stabilising effect like a weathervane. So when you drive it, what you feel is a tendency for the car to be undramatic."

We whip off bits of bodywork to see what's going on underneath. The pushrod rear suspension is a work of art, both sides interlinked through a complex network of rods, joints and plates. This is because, as Bowlby points out, "It's the back of the car that's doing all the work, really." The front is somewhat less convincing from my layman's perspective. The movement of those skinny wheels is controlled by the suspension from a mountain bike.

You'd be mistaken if you thought there was anything Heath Robinsonesque about the Deltawing, though. Tap the dense carbon tub, look at the effort and investment that's gone in and realise this car completely transcends its racing pedigree. Petit Le Mans was only its second race - and first finish (it was taken out at Le Mans proper by a Toyota prototype). It's a brave project for Bowlby personally and Nissan commercially.

And it's fast: half the power, weight and aerodynamic drag of a ‘proper' LMP2 car and yet able to lap at the same pace. But not in my hands, not here. Road Atlanta is a ballsy, brilliant track, each lap containing several proper heart-in-mouth moments and an ability to induce panic out of nowhere if you get it wrong due to the lack of run-off. It's a sharply administered poke in the eye of anyone who thinks the Yanks only turn left.

I passenger Gunnar Jeannette in a GT-R so he can give me some pointers. However, I'm too busy marvelling at the amount of ascent and descent, and panicking about the two blind crests to take in most of what he tells me. The main one, the one I don't forget, is don't clip kerbs with the front wheels. Obviously.

My turn. To be perfectly honest, I'm not so much nervous as excited. It's ‘only' 300bhp, and the power-to-weight ratio is no more aggressive than in a supercharged Ariel Atom. Granted, that is one of the very fastest road cars, but it seems manageable when I've got slicks, warm, clean sunshine and a car that looks aggressively comical rather than downright evil.

Fire-proofed from scalp to ankle and with Lucas's HANS device doing the carbon collar duties, I wriggle into the foetal seat and wait there, helpless as a baby, while black-clad mechanics drop the Deltawing off its jacks, unplug laptops and tighten my belts. Now it's allup to me. Wait for the man at the front to make a twirly gesture, then flick ignition to P2 and press the start button until the engine catches. It's nothing like a 1.6-litre four, obviously - much angrier - then plunge the heavy clutch, thumb the green neutral button on the steering wheel and simultaneously pull the right-hand paddle for first. Clank. Give it some revs, allow the clutch to push back and we're off, rattling down the pits in a very tall first gear.

Now, as I warily pilot my out lap, sat at half the height of the GT-R, I decide there are actually six blind crests here, and that I really can't see over the dash. I can see plenty out the back, thanks to the giant widescreen mirrors demanded by race regs (they add a whopping six per cent to its aero drag), but there's nothing chasing me out here.

And then something remarkable happens. By lap two, I'm entirely comfortable. It's a piece of cake to drive, will even change up automatically if you clip the 7,300rpm limiter but, more than that, does nothing scary or dramatically different to any other car. The technique is different, though. Braking deep into the apex is a no-no; it's far better to slow soon, turn in fast and then get back on the power earlier than you think possible. It's a conservative driving style, but one that suits the layout and weight distribution perfectly.

But it's the way it changes direction that's the stand-out sensation here. The weightless front has no inertia, therefore acting like a rudder through the tarmac - the Deltawing doing an enormously convincing Scalextric impression. You expect the downside of this ability to be stability - perhaps a tendency to hunt down cambers and ruts, but, no, it has a dart-like purity and smoothness to it. And due to reasons that Bowlby painstakingly explained to me but I fundamentally failed to grasp, there's very little weight transfer, so when you punch the power mid-corner, it doesn't lift the nose and push into understeer.

The corner leading onto the long, long back straight is taken in first gear, giving the Deltawing the perfect opportunity to demonstrate its other party trick. Acceleration. Now, all racing cars are fast, but downforce, which works so well through quick corners is, for obvious reasons, the enemy of top speed. But the low-drag Deltawing just keeps on accelerating, engine thrashing, turbo punching, through each of the five gears. I know it'll take the kink flat, and although I'm not foolhardy enough to check, it happily clocks 150mph and feels so stable, so confidence-inspiring, so easy with it. Although my experience is far from expansive, the Deltawing is the friendliest racing car I've driven.

It also moves very naturally, with lovely balance and loads of feel. The Deltawing is so supple that I imagine it's an easy car to race, although both drivers later say the super-direct steering's lack of power assistance is a real workout. But, even so, this is not a car you have to make allowances for; Bowlby has created a car that bends the laws of physics to its own purpose.

The last couple of laps are wonderful. I'm getting used to the dips and swerves of Road Atlanta, and the Deltawing is so reassuring, at its best through quick, sweeping direction changes. It's approachable and fun, which is what I want it to be. But, more importantly, for the team and people involved, it works, it's fast and now it has proved itself. Congratulations, Deltawing, for having proved there's another way.