what has become known as a ‘slingshot’ effect,

flooring the accelerator in his car and popping

out from the slipstream to overtake. Against the

odds, he won the race.

I come across trucks and tractors all

the time that I can slipstream behind,

helping me to get to work quicker –

and home again quicker, too. I keep

my wits about me, mind you, to make

sure that I don’t come a cropper!

Using the ‘slingshot’ is something that

everyone in motorsport now tries to do, but

the NASCAR teams also found another use

for the slipstream, which they also refer to

as the ‘draft’. On the circuits at Daytona and

Talladega, drivers developed a technique that

they called ‘bump drafting’. Basically, racing

teammates worked together with the rear car

driving in the slipstream, then pulling forward

to nudge the lead car and shove him along a bit

faster. Given that these cars can top 200 mph,

deliberately shunting the car in front seems

like madness, but two cars ‘bump drafting’ have

been known to run 15 mph faster than they

could on their own.

When you see lorries on the motorways

rumbling along so close behind one another

that you couldn’t slip a copy of the Highway

Code between them, you can bet that the

driver behind is saving fuel by driving in the

slipstream of the truck in front. It has been

shown that a car driving in the slipstream of

a truck can use up to around 40% less fuel.

Given that you have to be no more than 10 feet

(3 metres) behind the truck, it’s certainly not to

be recommended. If you’re that close, the truck

driver might not be able to see you, and if he

slams on his brakes you won’t have enough time

to react and will plough into the back of him.

For lorry drivers, on the other hand, it’s not quite

as risky a business. A truck is big enough for

the driver in front to see it and, what’s more, he

quite likes having it there. Why? Because of the

way that slipstreaming works, the truck behind

deflects some of the turbulent air flow that

would normally collapse in behind the leading

truck. This air can actually serve to hold the

truck back, so with another driver right behind

him the lead driver also benefits from a slight

fuel saving. They can work together to save each

other a few quid!

I have to admit, I’ve used the slipstream effect as
well – on my pushbike. Cycling 35 miles to work
every day, I come across trucks and tractors all
the time that I can slipstream behind, helping me
to get to work quicker – and home again quicker,
too. I keep my wits about me, mind you, to make
sure that I don’t come a cropper!

Above: Me against a racing truck? I wouldn’t have
a hope – but the truck was key to me beating
the record.

sitting in the slipstream    29