EJ12 Part 8

	See also: The car for 2002 The timescales The design process The regulation changes Making it happen The monocoque Vehicle dynamics Front suspension The uprights Rear suspension

EJ12 - the transmission

The gearbox is one of the most complex parts on a Formula 1 car. We asked Ian Hall, Head of Transmissions, to explain what goes into its design and build.

Q) Why do you need to produce a different gearbox every year?

IH) "Its complexity comes from trying to take weight out of it, while making it as simple and strong as possible. We produce a new one each year, because you can always do it better and move forward. The design philosophy is to take the existing technology and push it as far as you can but it's always one of those Catch 22 situations whereby you have to balance pushing it to the limit with making sure you have a reliable gearbox."

Q) Does the gearbox represent a big part of the car's weight?

IH) "It's less than 10% of the weight of the car, but reducing it is a real challenge. Since I started at Jordan, five years ago we are now running the best part of 15 kilos lighter."

Q) How much of that is down to design and how much to materials?

IH) "Most of that comes from the design, but I think innovations in materials will start to show through in the next few years."

Q) How do you start the design process?

IH) "The first fundamental decision is based on information Honda supplies us, regarding their predicted power curves on the new engine. These can be put into a lap simulation programme and you can then decide between building a 6 or 7 speed gearbox. Next, you re-evaluate different layouts, making sure the basic principles of the gearbox are correct for the philosophies of the design and the packaging of the car. The aerodynamic regulations have not changed much, so the philosophy of the back shape of the car has been fairly consistent year to year but our job is always to make the box smaller to give the aerodynamicist more room.

We started producing initial layouts for EJ12 as soon as EJ11 began running. You start with a list of developments you'd like to incorporate in the box. It depends on whether the company is prepared to take more of a risk to get more gains or whether they want a more conservative gearbox. You have to do a risk evaluation on some of the new features you want to include in the new gearbox. When you've decided which new parts you're prepared to take a risk on you can then define the internal layout of the new gearbox. The casing then follows.

The casing is the longest lead item part and has to be started first. The layout of the internals is based around making the outside shape as small as possible, to fit into the available envelope provided by the aerodynamicists which, in the early stages is estimated and based on previous experience. Then the casing is defined at the front end by the shape of the engine and at the back end and along its length by minimising it around the internals. However, the gearbox is also a structural part of the car, as it supports the whole rear suspension so it has to be a structurally sound box. A lot of finite element analysis work goes into checking the weight and stiffness of the casing."

Q) Why does it take so long to produce?

IH) "We use a cast magnesium gearbox. It takes around 6 weeks to convert its basic shape into a fully defined gearbox casing and a further 6-8 weeks of pattern work and 2 weeks to cast it. We have to take into account where the suspension designers want to mount the rear suspension, so that we can then draw up the pick-up points. Then another 6 weeks is required for the initial machining of the gearbox casing, followed by the initial gearbox build, which in a perfect world would take about a week but usually takes longer."

Q) Is all the work done in-house?

IH) "No, probably 60% of the gearbox internals are manufactured by X-trac, who supply the majority of F1 teams."

Q) How many gearboxes do you aim to have ready before the first race in Melbourne?

IH) "We need a minimum of five gearboxes to go to Melbourne, but normally you'd aim to have more than that: a box for the T-car, a Friday and Saturday box for both race cars, a Sunday one for both cars and then one spare. In the course of the season we'll get through about 25 gearbox casings. Some internal parts only last 400 kms., while others will do 4000 kms. throughout the season."