First unveiled at last year’s Frankfurt motor show, the Concept IAA show car is not only a product of Mercedes-Benz’s current “sensual purity” design philosophy, but also a demonstrator of what aerodynamic technologies the brand’s future cars will incorporate.
In point of fact, the acronym IAA stands for “Intelligent Aerodynamic Automobile”, which further hints at the car’s streamlined body that has the ability to change shape while driving on the road.
On reaching a speed of 50 mph, the “drop shape” vehicle switches automatically from “design mode” to something called “aerodynamic mode”, whereupon numerous active aerodynamic measures alter its appearance. As a result of this transformation, the Cd value improves from 0.25 to 0.19 – claimed by Mercedes to be a new world record for a four-door four-seater.
Some of the key aerodynamic features include the front flaps in the front bumper in front of the wheel arches that move outwards by 25 millimetres and 20 millimetres to the rear, up to the rear edge of the wheel crescent. This “substantially” improves the inflow of air to the wheels and the flow of air over the front wheel arches, say the designers. The louvre in the front bumper also moves 60 millimetres to the rear, improving the flow of air towards the underbody.
Along the sides, as well as windows which fit flush on the outside, the omission of door openers and lowering of the chassis, there are “active rims” that alter their concavity with the aid of centrifugal force from 55 to 0 millimetres, transforming them from 5-spoke wheels into flat disc wheels.
However, the most noticeable active aerodynamic element is at the rear: in conjunction with the diffuser, the rear extension which is extendable by up to 390 millimetres means the air flow hugs the vehicle more closely and that the after-flow zone behind the vehicle’s rear end is substantially smaller. The rear extension in “boat tail” design consists of eight segments produced in CFRP in a sandwich structure which close to form a ring.
“The ‘Concept IAA’ continues our series of visionary concept cars,” explains Gorden Wagener, head of design at Daimler. “The symbiosis of alluring forms showcasing intelligent aerodynamics is an expression of our unique Mercedes-Benz design philosophy.”
Underneath, the concept car is powered by a petrol/electric plug-in hybrid drive with a total output of 275 bhp, which provides it with a claimed top speed of over 155 mph. CO2 emissions and electric range is said to depend on the mode in which the vehicle is tested: in aerodynamic mode it manages an all-electric range of 41 miles and emits 28 g/km; in design mode the range stands at 39 miles and CO2 emissions at 31 g/km.
Inside, the concept car continues the design line of the S-Class and S-Class Coupé, offering new touch-based functions and providing an idea of what the interior of a business saloon might look like in the near future.