Starter motor

When a grand prix driver prepares to go racing, he carries with him a number of objects: water bottle, helmet and earphones among them. One thing he doesn’t take is a set of keys; but then again, he does not need them to start a Formula 1 car.
At the beginning of a race, a complex system is deployed to breathe life into a Formula One engine. Numerous components are utilised in this secretive action, without which the car would go nowhere. When you consider that a racing V8 using in F1 is around ten times more powerful than a road car powerplant, you realise that it takes more than just the twist of a key to get it running.

The electrical starter motor is an external unit, held by a mechanic, which features a long wand that is plugged into the back of the gearbox. In simple terms, when he pushes the starter motor’s button, 24 volts are put through the gearbox to turn the engine. The starter has a remote battery supply, which is fitted to a trolley and pulled by the mechanic, the car either being started on the grid before a race, or in the garage or pitlane during testing.

"First of all, the mechanic inserts the wand in the gearbox," explains Andy Barber, McLaren Racing Sub- Assembly Technician."He then receives a signal to push the starter motor button. This turns the engine over until the engineers are happy with the engine speed and oil pressure and – using a laptop – they will effectively turn the ignition on."

"Because the motor has such a kick in it, there is a reaction arm which hooks up on to the rear wing to stop it coming out of the mechanic’s hand."

The starter motor features a set of gears and clutch, and as the engine will move five times faster than this, for safety there is a sprag clutch. This acts like the freewheel on a bicycle, allowing the mechanic to withdraw the wand without any danger to himself. Another safety measure is the break-off clutch, which will prevent an accident should the engine backfire.

While the starter motor itself is an off-the-shelf unit, modified to cope with the high voltage passed through it, the wand, gears, clutch and electronics are all produced in-house at the McLaren Technology Centre. A range of materials are used for the construction, including aluminium for the main body and steel for the wand.
"The starter is made to be reliable, not light, which is one of the benefits of having an external unit,"explains Barber. "In the past, when we had an on-board starter, we wanted it to be as light as possible so we used an air starter. Now we concentrate on durability and this is generally a trouble-free piece of equipment."

Overall length: 120cm
Weight: 15 kilos
Power 24 volts