Mercedes reveals Concept IAA shape-shifting coupe

MERCEDES-BENZ has taken active aerodynamics to another level with the radical Concept Intelligent Aerodynamic Automobile (or Concept IAA) – revealed at the 2015 Frankfurt motor show – which changes shape at 80km/h for better aero efficiency.

The sleek and svelte four-door also gives a clue to the next generation CLS four-door coupe, due in 2017 or 2018.

But the aerodynamic package is the headline act for a car Mercedes-Benz describes as “two cars in one: an aerodynamics world champion and a four-door coupé embodying irresistible design”.

The keys to the Concept IAA’s split personality are eight extendable segments at its retro-infused rump, which extend the car by 390mm (the wheelbase remains the same). It takes the body from a lengthy 5040mm to 5430mm.

Louvres in the front bump move 60mm rearward and there are also flaps at the front and rear which extend 25mm and 20mm respectively, to divert air better around the nose.

Even the wheels change at the 80km/h transformation speed, from “design mode” to “aerodynamic mode”: the deep dish transforms to a flatter surface designed to further smooth the air flow.

When stretched and ready for high-speed driving, the Concept IAA has a co-efficient of drag of 0.19, significantly less than the 0.24 of the Tesla Model S and tantalising close to the 0.189 of the Volkswagen XL1, which was designed to show how far fuel savings could be pushed.

“The Concept IAA applies intelligent innovations to resolve the conflicting aims of functionality and aesthetics, and shows that we still have plenty of ideas on how to achieve further improvements in efficiency," says Thomas Weber, board member and the head of research for Mercedes-Benz cars.

Inside, the Concept IAA has elements of the current S-Class, including its stylised circular air vents and dominant digital instruments that fuse into the central touchscreen. Touch pads are a theme throughout the futuristic interior that’s coloured electric blue, silver and white.

“The Concept IAA symbolises the emotional core of Mercedes-Benz … and it shows in a host of details what our customers can look forward to in future production models," says Ola Kallenius, Daimler board member and the head of sales and marketing for Mercedes-Benz.

Underneath, the Concept IAA uses a petrol-electric plug-in drivetrain good for 205kW and a 250km/h top speed.

While the radical aerodynamic transformation is unlikely to translate into a production model in the near future, expect it to give clues as to next generation active aerodynamics.

The Concept IAA also expresses some of the design themes being explored for the third generation CLS due within a few years.