The wing mirrorThere wouldn't seem to be much unique about a Formula 1 wing mirror. After all, its purpose is clear – to allow the driver to see competitors behind him and whether his tyres are suffering from excessive wear or blistering.
Surely the design is as basic as deciding how big it needs to be and where it should go? Rarely is life in Formula 1 simple, though.
The wing mirror unit has to satisfy a number of requirements from the FIA, motorsport's governing body. The reflective surface must measure 150mm wide by 50mm high, with a minimum corner radius of 10mm. The mirrors must also be placed in accordance with FIA guidelines to ensure the driver has a satisfactory field of view. He must satisfy an FIA delegate of this by reading the lettering off a board held at a pre-determined distance behind the car.
The design also has to take into account aerodynamics, as the mirrors are exposed in a crucial position for the airflow around the chassis. "In aerodynamic terms, we'd actually rather not have the mirrors, so we have to be careful where we place them and how we design their shape," admits Team McLaren Mercedes Design Engineer Steve Talbot. As a result, the mirrors have an aerodynamically-optimised shell shape, derived from computational fluid dynamics software and wind tunnel models. Another major factor is mass. "Because the mirror unit is so high up on the car, weight is a primary issue to try and keep the car's centre of gravity as low as possible," Steve adds.
To reduce weight, the shell and stem are made of carbon fibre, while the mirrored surface is made from Perspex for durability and safety. The units are attached to the car with titanium fittings, as they are frequently moved and re-fitted to the car. Such a lightweight unit is susceptible to vibrations from the high-speed airflow and engine vibrations transmitted through the chassis, however, so the mirror surface is attached to the shell with anti-vibration mountings to prevent the image blurring.
Adjustment of the mirror for the driver is also limited. "Road car-style adjustment would be too heavy, and I don't think they have time to adjust their mirrors during a race!" jokes Steve. Instead a small screw is used in the garage to allow limited rotational and angular adjustment. By the time the unit is on the car, though, it should be almost perfectly positioned thanks to pre-season work by the engineers.
If that wasn't complex enough, the mirror units have, in the past, even had to be redesigned for the Monaco Grand Prix. "The drivers need a clear view of the front wheels so they can position the car close to the barriers," Steve explains. "It's not just a case of moving the mirrors. They have to be redesigned to ensure all of the FIA and aerodynamic criteria are met."
In 2002, the team adopted a double-faceted mirror with an angled segment for the MP4-17 that widened the field of view in the same way as a blind-spot mirror on a road car. Rarely is life simple in Formula 1, but Team McLaren Mercedes certainly finds ways to solve the problems.
Weight: 160g per unit (320g per car)
Dimensions: 150mm by 50mm face area, with a depth of around 80mm
Material: Perspex for the mirror surface, carbon fibre for the shell and stem, with a titanium chassic attachment
Number per season: 12 sets (one per chassis plus spares) depending on damage