Titanium upright design and manufacture

In what seems a previous life now I used to design Formula 1 cars. I thought you might be interested in some of the details of these extreme parts that don't come to light normally.

This picture is of a rear upright from the 2001 Prost AP03 car. It's fabricated from Titanium and a pair of them cost around £15,000 to produce.

The centre of the upright is made from a solid billet of Titanium 6Al4V, the first stage in the process is to wire erode all the triangular shape cut outs in the billet. These cut outs are used to pass cooling air from the brake duct through to the brake disc. The wiring eroding took about 20 hours from memory. This upright has a steel axle in it made in California by Metalore from a special steel that undergoes a special surface treatment. You can probably just make out that the tracks for the CV joint are machined directly into the axle.

The upright has a pair of pretty slender bearings that on this car featured ceramic balls. The ceramic balls reduced the rolling friction by an incredible amount and they are also considered self healing in that the balls are so hard if there's any damage to the bearing races the balls will smooth it out.

The outer parts of the upright were fabricated from Titanium sheet, normally 1.2mm thick, often formed over knocking blocks to get the shapes that we required. Brake caliper pickups, lower wishbone pickups, top wishbone and track rod pick ups are all Titanium machined pieces that are welded into the sheet.

Titanium has to be welded in an inert atmosphere or else is gets contaminated and can fail so we built special chambers where the Titanium parts were placed and the air removed and replaced with pure Argon. The welders had to weld them like you see Biologists in labs, buy placing their arms through in-built rubber gloves and looking through a window equipped with auto-darkening filters.

After welding the uprights were heat treated to remove any internal stresses.

The accuracy required means that any distortion due to welding would be unacceptable, so each critical part of the upright will have a stock of material on that after welding gets machined back to where it should be. The whole upright assembly would therefore be put on a lathe first and have the bearing features machined and then go onto one of our 4 axis milling machines to have all the other pickup points and mounting points machined in exactly the right places.

After machining these uprights were then shot peened and where then inspected and finally fitted to the car. The design of the rear upright system, including the upright itself, axle, wheel, brake package, carbon brake duct and tooling and all the data logging sensors for things like brake temperature took approx. 12 weeks each year and a pair of these uprights could just about be made in a week if two fabricators worked on them. I think we made 5 sets for the first Grand Prix each year and then another 5 sets during the season dependent on damage etc.

Below is a picture of the AP04 front upright, that shows the Titanium axle, Aluminium wheel nut and the full front brake duct assembly.