Some time this past year, there were some messages about the 'new' IR-18 using the same physics as the IR-12. The response was that was true since the IR-18 was essentially the same car as the IR-12. I sensed there were some who did not think that was accurate. I'm re-living this due to discussions by the Indycar folks about modernizing the engine package again for the IR-18. Many driver's have asked for a new car as well, but that request seems to be falling on deaf ears. Here is a tweet that basically confirms the Chassis is now over a decade old. Penske Entertainment CEO Mark Miles believes IndyCar stands to gain more from focusing on its new hybrid power units than developing a new chassis to replace the Dallara DW12, which was introduced in 2012.
Well yeah, but no. The basic chassis is as it was in DW12 days. But they've done a lot of modifications to it. They added side intrusion panels (after Justin Wilson broke his hip), and of course they added the aeroscreen which required a whole bunch of work to the top of the chassis to add the frame. It's entirely possible they changed the suspension pickup points, and at the very least, they've done modifications to the suspension arms and also the steering arms so they fail better in hits. That comes with or without a geometry change. Then, they changed the brakes into ceramic ones, different to the originals. The car has also had 3 different aero packages, including more ground effect on the latest one where they'd had more flat bottom approach prior. They've changed the crash attenuator in the back, lightened the gearbox. One of the engines went from single turbo to dual turbos so they are now both the same. I believe for the chassis mods, you had to send the chasis back to the factory for them to do the changes, mainly. It's possible the very latest chassis have done a better job integrating in some of the add-ons. Teams do replace their chassis as a result of crash damage or just to get fresh ones. For next season, its the same chassis, but it isn't. The new hybrid system sits between the engine and gearbox, and I think they've done some things to lighten up the rear of the car because adding weight back there isn't ideal. (It's not a battery, you can't put it where you want, its inline with the powertrain). They are also doing a new aeroscreen frame that is about half the weight of the existing one. Dallara have made a fortune off that car. 13 years, used to be like 5 or 6 max. Plus all the spares, oval crash damage, etc. They've made attempts to get some parts available from third parties/locals, but still the vast majority are done by Dallara. What a money maker. Just think, if some had their way, we'd be looking at a bunch of DeltaWings...
I think the chassis itself being the same wasn't the core of the complaint. There appeared to be very little aero change either, which didnt seem to match the car updates. If I recall correctly.
When they were developing the IR12, it had all sorts of problems with weight distribution (too much to the rear) and aero imbalance. Dan Wheldon, who did much of the development driving, hated it. It would swap ends on ovals without warning, and pendulum. It also had hella drag. They had to do a LOT of work before Dan was happy, and then of course he died and they renamed it DW12 in his honor, he never got to race it. When they introduced the manufacturer aero kits, they sprouted all sorts of ugly appendages. This was all so they could claim a "new track record!" at Indy. It had terrible aero problems, and would take off if you put it sideways especially at Indy. Cut big holes in the front of the sidepods to accomodate this. Those initial cars had the big airbox. Ugly as sin. When they got the guy to do the aero redesign to make the IR18, he did a pretty good job. Took off the airbox, slimmed it down, made it sleek as the chassis could manage, took off all the furniture out the back (the Kardashians). They had to take the artwork - for it was penned by a non-aerodynamicist - and then tweak it to actually work. Added things like the center wickers. They had no end of aero parts - to the front of the sidepods as strakes, to fill in the prior sidepod front holes, to add strakes to the diffuser, to do fairings for the gearbox etc. But of course after Robbie Wickens and others, they had to do something about the safety, and the aeroscreen was the result. I'm used to looking at it now, and they did a reasonable job incorporating it into the aesthetics, but its still a hack, just like a halo would be. A new car would be able to better integrate that, or even make a fully closed and sleeker cockpit, jet fighter style and with more transparent area to it hopefully. The problem with the aeroscreen is you basically now can't see the drivers (hands) at work.
It probably their business model, but when working on some physics updates to the IL-15 Indy Lights car, I was amazed on how many shared or very similar components there are between Dallara's models. It was something I never noticed before. At least based on appearance. I'm pretty sure the rear wing elements of the original DW12 and the IL-15 are the same. The front wing mainplane on the F3 car seems to be used on multiple cars. Super Formula and GP2 cars seem almost identical. As the have a factory in Indianapolis, I could see a production line set up where the just do run of 200-300 of elements, and it just gets put on everything. It does make one wonder that if Indycar went with a different manufacturer back in 2012, if we'd have a different chassis by now. The oval racing makes Indycar unique. Which is why I think you don't see the SF-GP2 chassis used for Indycar. It has to be a bespoke model. It could be the hesitation for Indycar to change its model. Say what you will about the Deltawing. But that car would have made Indycar unique from the rest of the openwheel world. The 2L Turbo engine, they would probably have a lot more engine manufactures in it. I was particular to the Swift concept. https://www.racecar-engineering.com/articles/the-indycars-that-never-were/
The IR12 prototypes from 2011 were really cool. Check these out. View attachment upload_2023-12-8_15-56-13.png
