Starter Motor

Geared tip of the probe that is plugged into the back of the gearbox

Starter motor with external battery power supply

How the External Starter Works

At the beginning of a race, a complex procedure is required to start a Formula One engine. Numerous components are utilised in this process, without which the car would go nowhere. When considering that a racing V8 used in F1 is around ten times more powerful than a road car engine, 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 probe that is plugged into the back of the gearbox and engages two pairs of gears. First, the mechanic inserts the probe into the gearbox. He then receives a signal to push the starter motor button. This turns the engine over until the engineers are satisfied with the engine speed and oil pressure, and – using a laptop – they effectively turn the ignition on.

In simple terms, when the mechanic pushes the starter motor’s button, 24 volts start the handheld electric motor, which through a long shaft begins to turn the gearbox and, through the gearbox, turns the engine. Because the motor has such a kick, there is a reaction arm which hooks onto the rear wing or to the ground to stop it coming out of the mechanic’s hand.

Safety Features

The starter motor features a set of gears and a clutch, and as the engine will move five times faster than the starter, a spring clutch is included for safety. This acts like the freewheel on a bicycle, allowing the mechanic to withdraw the probe 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 probe, gears, clutch, and electronics are all produced in-house by the teams.

Construction and Durability

A range of materials are used for the construction, including aluminium for the main body and steel for the probe.

The starter is made to be reliable, not light, which is one of the benefits of having an external unit. In the past, when cars had an on-board starter, teams wanted it to be as light as possible, so an air starter was used. With the external unit, durability is the priority, and this is generally a trouble-free piece of equipment.

2014 Rule Change

From the 2014 season onwards, following the major engine and KERS rule change, the FIA included in the Formula 1 rule book that an on-board starter motor must be fitted and that the driver must be able to start the engine while seated in the cockpit.

FIA Technical Regulations

5.18 Starting the engine :

It must be possible for the driver to start the engine at any time when seated normally at the wheel and without any external assistance.