Top Gear drives the DeltaWing!

Well, it doesn't do what you expect. This is a very good thing. Everything you know about cars shaped like triangles tells you that it must be hideously unstable and, with that narrow front, very prone to understeer. It must therefore handle like a Robin Reliant. But the DeltaWing is neither unstable, nor lacking grip at the front end. The physics behind this is simultaneously simple and yet difficult to get your head around. Basically (very basically), tyre grip is matched to weight and since the front of the car has no weight, it needs comparatively less grip. Ben Bowlby, the man whose brainchild the DeltaWing is, proved this by picking the nose up.

He did what?

Lifted the front of the car clean off the ground. By himself. But the front only accounts for 28 per cent of the DeltaWing's sub-500kg kerbweight, so the front wheels can be as narrow as those fitted to an old 2CV. Literally. In fact the spare tyres they use when pushing the DeltaWing around the paddock are old 2CV tyres.

But that's just madness, isn't it?

No, it's physics and Ben Bowlby is a very clever man. It's best to accept that it just works and leave it at that. But first, given what you now know about the front of the car not having to work too hard, I'd like you to guess where the front dampers come from.

Um, a road car of some description? How about a Nissan Micra?

Nope, a mountain bike. Like I said, it's best not to think about how it works.

But it can't be that sharp and grippy turning into corners at race speeds?

Wrong again. There's a monstrous amount of bite and agility on turn in and at the Road Atlanta circuit the DeltaWing is pulling up to 4g through some corners. And this without a single wing. Although saying that, it's worth pointing out that it does have a significant amount of underbody aero...

OK, so is it easy to drive?

Once up and running. Like any race car there's a frankly baffling number of switches and buttons, the steering wheel is entirely bewildering, you're sat in a cupped seat with your legs way higher than your buttocks and hemmed in by high cockpit sides and a pair of outsize mirrors (which also add six per cent to the car's overall drag). But once you're rolling you forget all that and you don't even need to pull a paddle to change up - once the car hits 7300rpm it upshifts automatically. Of course getting to that stage requires some bravery. The DeltaWing, with 300bhp driving under half a tonne, is a very fast car. Especially at somewhere like Road Atlanta, which is a circuit for grown-ups.

What do you mean by that?

I mean that the circuit is far scarier than the car. Many corners are blind and have to be taken on trust, there's a terrific amount of elevation change and precious little run-off. If you think this makes it sound like the Nurburgring, you wouldn't be far off. You'll only be quick here in a friendly car and given that I was able to hop in and feel comfortable within a couple of laps despite never having driven a metre of the place before, speaks volumes.

So you don't have to make any allowances for it?

You do need to remember that the rear is much wider than the front, so you have to keep the front wheels a foot or two out from the kerb, but as you're so low in the car and can't really see the dart-like nose, you tend not to think too much about the physics and instead just drive it. Technique is important. You drive the car quite conservatively: brake in a straight line, turn in fast, then immediately get back on the power. It's the rear that's doing all the work here, so you need to use it. Use the traction, maximise the tyre grip. That's why the guys that race it have found that it's fast in different places to other cars. It behaves differently.

Such as?

Well cars with heavier active downforce can brake later, right up to the apex, a technique called trail braking. The DeltaWing is slower into corners, but quicker out of them. And down the straights it's much faster. Cars with big wings generate more and more downforce the quicker they go, which really harms acceleration. The DeltaWing just keeps on pulling. It has a smaller frontal area and it's shape means it pushes the air out of the way more gradually.

Even with a mere 300bhp from a 1.6-litre turbo (an engine distantly related to that of the Nissan Juke), it was clocked at Le Mans at over 192mph. I've got no idea what speed I was doing down Road Atlanta's back straight as I haven't had a chance to look at the telemetry yet, but the DeltaWing was so planted and stable that big speeds are less scary here than in any other racing car I've driven. It doesn't hunt or follow cambers or dart or weave. It's remarkably vice-free.

Does that mean it's just a teeny bit dull to drive?

Not at all. It just drives cleanly and naturally. It's actually a ridiculous amount of fun to drive, not least because of the way the acceleration never lets up as it hurls its way between corners - no appreciable turbo lag, just this intoxicating eagerness to get to the next corner as soon as possible. And when you get there, the speed washes off so easily, and then the front tracks so lightly and accurately in, it's as if it has no inertia. Which, compared to other racing cars, it doesn't. The steering's lovely, too. You know exactly where you are with it because the narrow front tyres are easy enough to turn that power steering was deemed unnecessary. It never feels nervous, it just feels beautifully balanced - and given the way it looks, I just didn't expect that before driving it. If I'm honest, I'm still a bit baffled as I sit here now and write about it.

So what's next for the DeltaWing?

There's the rub, because at the moment there are no more plans for it. It might never race again. That would be a bitter disappointment, because I'd argue that this is one of the most radical and exciting racing cars since the days of Colin Chapman, six-wheel Tyrells and Brabham fan cars. It finished sixth overall at Road Atlanta three days ago in the Petit Le Mans 10 hour race and that despite having had a big shunt in practice.

Playing the devil's advocate here, didn't that prove the car has stability problems?

No, I don't think so. It's been tested in wind tunnels not only pointing forwards, but also sideways and backwards. At 180mph. It has special flaps on the back of the car that flip down into the airflow in the event of a high speed spin to prevent air getting underneath and lifting the rear. Again, I would tell you more, but Ben Bowlby is a much cleverer man than me and his explanations were very detailed and believable. But also occasionally quite complicated...

OK, so getting back to the future of this car.

It won't race at Le Mans next year - the race organisers there have already made that clear. The guys behind DeltaWing would love to see a new radical race formula, one that sets certain parameters, say 500kg and 300bhp, plus maybe a set amount of fuel, and then leave everything else to the designers and engineers to be as creative and clever as they can be. That, however, will take a long time to come to fruition, but wouldn't it be a brilliant showcase and an enthralling spectacle?

It certainly would - because people love this car, don't they?

It's been hugely well received everywhere it's been - for some fans that's purely down to the fact it looks like the Batmobile, but for others the fact it's new, it's different, it's radical and, above all, it works, make it a racing car worth celebrating.

Words: Ollie Marriage
Photography: Rowan Horncastle

Make sure you pick up the next edition of Top Gear magazine for the full story and pictures - out 7 November. And we'll have some video for you in the coming days as well...  

Well, it doesn't do what you expect. This is a very good thing. Everything you know about cars shaped like triangles tells you that it must be hideously unstable and, with that narrow front, very prone to understeer. It must therefore handle like a Robin Reliant. But the DeltaWing is neither unstable, nor lacking grip at the front end. The physics behind this is simultaneously simple and yet difficult to get your head around. Basically (very basically), tyre grip is matched to weight and since the front of the car has no weight, it needs comparatively less grip. Ben Bowlby, the man whose brainchild the DeltaWing is, proved this by picking the nose up.

He did what?

Lifted the front of the car clean off the ground. By himself. But the front only accounts for 28 per cent of the DeltaWing's sub-500kg kerbweight, so the front wheels can be as narrow as those fitted to an old 2CV. Literally. In fact the spare tyres they use when pushing the DeltaWing around the paddock are old 2CV tyres.

But that's just madness, isn't it?

No, it's physics and Ben Bowlby is a very clever man. It's best to accept that it just works and leave it at that. But first, given what you now know about the front of the car not having to work too hard, I'd like you to guess where the front dampers come from.

Um, a road car of some description? How about a Nissan Micra?

Nope, a mountain bike. Like I said, it's best not to think about how it works.

But it can't be that sharp and grippy turning into corners at race speeds?

Wrong again. There's a monstrous amount of bite and agility on turn in and at the Road Atlanta circuit the DeltaWing is pulling up to 4g through some corners. And this without a single wing. Although saying that, it's worth pointing out that it does have a significant amount of underbody aero...

OK, so is it easy to drive?

Once up and running. Like any race car there's a frankly baffling number of switches and buttons, the steering wheel is entirely bewildering, you're sat in a cupped seat with your legs way higher than your buttocks and hemmed in by high cockpit sides and a pair of outsize mirrors (which also add six per cent to the car's overall drag). But once you're rolling you forget all that and you don't even need to pull a paddle to change up - once the car hits 7300rpm it upshifts automatically. Of course getting to that stage requires some bravery. The DeltaWing, with 300bhp driving under half a tonne, is a very fast car. Especially at somewhere like Road Atlanta, which is a circuit for grown-ups.

What do you mean by that?

I mean that the circuit is far scarier than the car. Many corners are blind and have to be taken on trust, there's a terrific amount of elevation change and precious little run-off. If you think this makes it sound like the Nurburgring, you wouldn't be far off. You'll only be quick here in a friendly car and given that I was able to hop in and feel comfortable within a couple of laps despite never having driven a metre of the place before, speaks volumes.

So you don't have to make any allowances for it?

You do need to remember that the rear is much wider than the front, so you have to keep the front wheels a foot or two out from the kerb, but as you're so low in the car and can't really see the dart-like nose, you tend not to think too much about the physics and instead just drive it. Technique is important. You drive the car quite conservatively: brake in a straight line, turn in fast, then immediately get back on the power. It's the rear that's doing all the work here, so you need to use it. Use the traction, maximise the tyre grip. That's why the guys that race it have found that it's fast in different places to other cars. It behaves differently.

Such as?

Well cars with heavier active downforce can brake later, right up to the apex, a technique called trail braking. The DeltaWing is slower into corners, but quicker out of them. And down the straights it's much faster. Cars with big wings generate more and more downforce the quicker they go, which really harms acceleration. The DeltaWing just keeps on pulling. It has a smaller frontal area and it's shape means it pushes the air out of the way more gradually.

Even with a mere 300bhp from a 1.6-litre turbo (an engine distantly related to that of the Nissan Juke), it was clocked at Le Mans at over 192mph. I've got no idea what speed I was doing down Road Atlanta's back straight as I haven't had a chance to look at the telemetry yet, but the DeltaWing was so planted and stable that big speeds are less scary here than in any other racing car I've driven. It doesn't hunt or follow cambers or dart or weave. It's remarkably vice-free.

Does that mean it's just a teeny bit dull to drive?

Not at all. It just drives cleanly and naturally. It's actually a ridiculous amount of fun to drive, not least because of the way the acceleration never lets up as it hurls its way between corners - no appreciable turbo lag, just this intoxicating eagerness to get to the next corner as soon as possible. And when you get there, the speed washes off so easily, and then the front tracks so lightly and accurately in, it's as if it has no inertia. Which, compared to other racing cars, it doesn't. The steering's lovely, too. You know exactly where you are with it because the narrow front tyres are easy enough to turn that power steering was deemed unnecessary. It never feels nervous, it just feels beautifully balanced - and given the way it looks, I just didn't expect that before driving it. If I'm honest, I'm still a bit baffled as I sit here now and write about it.

So what's next for the DeltaWing?

There's the rub, because at the moment there are no more plans for it. It might never race again. That would be a bitter disappointment, because I'd argue that this is one of the most radical and exciting racing cars since the days of Colin Chapman, six-wheel Tyrells and Brabham fan cars. It finished sixth overall at Road Atlanta three days ago in the Petit Le Mans 10 hour race and that despite having had a big shunt in practice.

Playing the devil's advocate here, didn't that prove the car has stability problems?

No, I don't think so. It's been tested in wind tunnels not only pointing forwards, but also sideways and backwards. At 180mph. It has special flaps on the back of the car that flip down into the airflow in the event of a high speed spin to prevent air getting underneath and lifting the rear. Again, I would tell you more, but Ben Bowlby is a much cleverer man than me and his explanations were very detailed and believable. But also occasionally quite complicated...

OK, so getting back to the future of this car.

It won't race at Le Mans next year - the race organisers there have already made that clear. The guys behind DeltaWing would love to see a new radical race formula, one that sets certain parameters, say 500kg and 300bhp, plus maybe a set amount of fuel, and then leave everything else to the designers and engineers to be as creative and clever as they can be. That, however, will take a long time to come to fruition, but wouldn't it be a brilliant showcase and an enthralling spectacle?

It certainly would - because people love this car, don't they?

It's been hugely well received everywhere it's been - for some fans that's purely down to the fact it looks like the Batmobile, but for others the fact it's new, it's different, it's radical and, above all, it works, make it a racing car worth celebrating.

Words: Ollie Marriage
Photography: Rowan Horncastle

Make sure you pick up the next edition of Top Gear magazine for the full story and pictures - out 7 November. And we'll have some video for you in the coming days as well...