Fast cars: Full throttle with McLaren

In 1895 the first proper automobile race took place in France, where the winner made an average speed of 24.14 kph. Nowadays, the record set by a formula 1 car was 372.6kph and a lot of research goes into developing race cars to be as fast as possible. So buckle up, because I went to visit McLaren, who are at the cutting edge of car racing technologies...

Izzie - Now, we can do a show about speed without exploring race cars. Drivers of these lightweight speed machines really push the laws of physics to shed those all-important seconds off lap times and personal bests. But how do they actually work. I visited Dan Parry Williams, Director of Engineering and Design at McLaren, to see a McLaren supercar for myself.

[In background]

Which one are we going in?

Dan - That green one behind the van over there I think

Izzie - God, that's amazing! Outside of their garage was a range of impressive cars and aunt me over to a lime green 600LT. Safe to say, it's nothing like I've ever travelled in before.

How do I open the door?

Once I'd figured out the fancy car door, I sunk into the leather passenger seat and Dan and I drove around the local roads at the less exciting legal speed limit...

[In car]

Now this is something called a supercar, so what is so different from this car compared to what people might be familiar with when we look at a Formula 1 racing car?

Dan - Okay. While the Formula 1 racing car is first of all is a single seater designed for a specific formula, i.e. Formula 1, and it can only be used in closed circuit racing. Whereas obviously the car we are in today and all the McLaren automotive cars are roadgoing cars, albeit with a very strong track heritage, and they're designed for track use as well as driving on the road. So we’re going to a small local track, it's a safe place where we can let the engine rev a bit more in safety and can actually hear what the car really sounds like when you get the opportunity to open the throttle a bit.

Izzie - Cars like this can reach speeds of up to 200 miles per hour. Once we arrived at the test zone, Dan and I sat down to go through the design of the fast car.

Dan - Well, essentially, where applicants physics so the principles that underlie performance are all really defined by Isaac Newton. He developed his equations of motion and essentially we need to think about force at the wheels, so we need to think about weight, and we need to think about aerodynamics as the very fundamental principles.

Izzie - The force at the wheels are important to keep moving, and one such force is torque, which is generated by the engine. If you get a large torque working on a rapidly rotating engine axis, then you got a lot of power to get your car moving... and quickly.

Another force that racing enthusiasts might be familiar with is downforce.

Dan - Yes. The best way to think about downforce is to imagine the wings on an aeroplane. On racing cars, we just invert that wing.

Izzie - That's where those spoilers, that inverted wing, often found on the back of your car come into play.

Dan - Also, in many cases we design carefully the underside of the car in such a way that we, instead of generating lift, we generate downforce from those aerodynamic surfaces. The point of that is in order to be able to increase the force on the tyres so that they transfer more load onto the road surface and generate more grip when the car's going round corners.

Dan - We're working hard all the time and trying to improve not only downforce but also drag. You just have to stick your hand out the car window when you're travelling at 70 miles an hour and you can feel that resistance. Anything going through that fluid is generating drag and anything we can do to reduce that will mean that there's less energy required to push that vehicle through the air. So as well as the downforce, we need to do a lot of work with the overall shape of the car to make sure that it's as slippery as possible.

Izzie - And then we get to the tyres. The only point of contact between the car and the road. Racing cars will have tyres without tread to maximise the point of contact on the ground...

Dan - The better the tyre the more torque can be transferred to the road because that's the only way we can get performance.

Izzie - And then, what are some of the other design techniques that you can use to make sure that your car can go faster? I guess the material that is made from is incredibly important.

Dan - We employ a lot of carbon fibre in our cars. Carbon fibre is a material that first appeared in the aerospace industry and found its way into Formula 1 racing, and now we have exploited that material for supercars and we are using increasing amounts of it. It's a very rigid and very strong material for its weight and it also has really good properties in terms of energy absorption in a crash. So it's a great material to use for the structure of a high-performance car because we can make the car rigid, we can make the car strong, and we can make it light.

Izzie - And, therefore, the focus is on the power I guess?

Dan - Yeah. So having made it as light as we possibly can we then try to make it as powerful as we possibly can, and that's the starting point for a high-performance car.

Izzie - So can we actually go in the car?

Dan - Yeah, let's go. Are you ready?

Izzie - I am very much am. Here we go…

[car races off, engine roars]

Oh my god! My heart is absolutely racing.