XTRAC INDY GEARBOX
while only having to remove one corner of the car.’ While the top teams will probably still take off the ’box and have two separate ’boxes to suit different tracks, to teams that don’t have the budget for such extravagances these savings will be most welcome. Further time-saving benefits come from features such as the externally adjustable differential, which will allow rapid set up changes trackside.
In house gimbal test rig allowed Xtrac to do physical simulations of the g forces the gearbox will undergo on track
helped the design of the two structures to be fully integrated. The transmission’s lubrication
system has benefitted from the latest advances in gearbox design and simulation, not least the fact that Xtrac now has an in house gimbal test rig. The rig allows physical simulation of g forces under braking and cornering, providing validation for results of computational fluid dynamics simulations. Interestingly, the forces produced by racing on a banked oval are easy enough to accommodate when designing the system, the challenge was ensuring sufficient oil pick-up on road courses.
AUTOMATIC GEAR SHIFT One other area on which the design team concentrated was the integration of the Megaline Automatic Gear Shift (AGS) system. The previous 295 series ’box had started life as a manual unit and had the AGS grafted on later in its development, whereas the 1011 was always intended to use the system. Although the earlier integration had been successful, there were certain areas the design team wanted to ‘tidy up’. One of these was the provision of a reverse gear. In the 295, a reverse gear was a later
Xtrac took a huge risk signing up to the IndyCar project, agreeing to build 75 gearboxes and undertake all the development work themselves
addition, only required when road course events were introduced into the series. The 1011, on the other hand, was designed with it from the outset. While the system components
are sourced from Megaline, all of the calibration and software set up is done by Xtrac, with shift maps and timing critical to both the efficiency and longevity of the gearbox. As has already been
highlighted, IndyCar is keen for the DW12 to provide significant cost savings to teams. Though
the new transmission is very competitive on cost, the key savings will be in relation to service and maintenance man hours, as Billyeald explains: ‘In the past, when you wanted to change from a road course to an oval set up, it would involve taking the bevel gears out and removing the ’box from the car to access the drop gears. With the new one you can simply take the side cover off and change the final drive without disturbing the bevels. Swap the spool out for a diff and you are done. All
FINANCIAL COMMITMENT Beyond the basic engineering challenge, the scale of production required by IndyCar presented large scale logistical and financial challenges to Xtrac. Simply taking on the project was a considerable undertaking, as technical director, Adrian Moore, underlines. ‘I think the biggest thing for us from a commercial side is the fact that we had to commit to this project early in the process. We get our income from selling gearboxes. No one paid us to develop the 1011, so it is a very long term project for us. We have to make 75 ’boxes, 30 plus by the end of January. So that scale of financial commitment is enormous and the technical risk of doing it is large. I am not convinced that any other racing manufacturer currently has either the financial resources or technical competence to take that risk.’ This volume of production could be accommodated by the company’s existing manufacturing set up, but it still required very careful planning of the production process to avoid bottlenecks during development. While there is no doubt
that Xtrac can produce a far more advanced gearbox than the 1011 – as evidenced by the company’s F1 involvement – the new transmission is an excellent example of cooperative engineering. In a market increasingly dominated by one-make series, the ability to produce high specification transmissions to a tight budget, yet tailored to a dedicated set of requirements, is bound to be advantageous.
“We wanted to maintain serviceability, with the gear cluster coming out of the back”
May 2012 •
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