What exactly is "an open wheeled catagory"?

There's much latitude in the F/B regs (mathmatically and geometrically) for semi-wheel/tire enclosure.


So, what is the actual definiton of "open wheel" in the SCCA? Would just an opening at top of the wheel mean the wheels were exposed (all this is assuming you stayed within the height-width body dimentions for the class?


Would it mean no skirts along the side of the tire/wheel (on the insides, say, of the fronts -- again staying within body dimension regs)?


Some of the F/500 cars really begin to push in this area -- and the aero advantages are obvious. And, of course, the old wide-nose FB Chevrons and etc., were essentially sports racers in front of the front wheels.... and it all could have been taken farther.

What are the precedents in this area? What exactly will the scrutineers accept in this area before you've gone too far? I'm sure a lot of folks have at least thought about what the limits would be... one series of posts in fact dicussed this area in some detail -- but I cannot refind the thing. And we're building our "kickers" now.

Any thoughts would be greatly appreciated. Or, if anyone know where that series of posts on the subject could found, it would be a great help. I know both Richard Pare and Jay Novak weighed in... and I'd sure like to read what they had to say again.

Thanks for anything ---

Nothing that I can seen in the regs gives an actual definition of "open wheel" - it is a term that has had a universally understood meaning of "no fenders or wheel enclosures" for 90+ years or so, and I've never seen regulations that specify "no fenders or enclosures".

I think, however, that you could use vertical "skirts" alongside the the inner edge of the rear wheels without causing too much heartache. However, any attempt to have them curve outwards over the contact patch area would most likely put them in the area where they could be protested as "fenders" and be successfully protested even though there is no official prohibition against them in the class.

Using some sort of wheel enclosure out the the max body width could indeed be tried, but be prepared to have the rule defined better and their use made illegal very quickly thereafter!

It appears in FB you could build something that almost matches the current Indy car. No so in FC.
The max width rules for the front wings make it hard to really pull off a sportscar type nose. Because the max width being 185 for the car but only 135 for the nose.

Measurement "E" on the chart might be something to work around if your creation was ruled a "aerodynamic device" instead of bodywork. :confused: :rolleyes:

A very interesting area for rules interpretation, I must say!

The next question is this: How far can you go in using brake ducts to capture and redirect flow around the tires? At what point does it become an aerodynamic device and become subject to whatever the restriction are on them?

My guess is that you could safely make a "traditional" brake duct that scoop in air along the inside edge of the tire and dump it into the middle of the wheel. Too much beyond that will at the minimum raise eyebrows, but most likely would not get you protested unless you were winning.

Richard, not sure if you caught this over the weekend, but at the Canadian F1 race Red Bull was ordered to take off their front uprights, which contained holes used to direct air not only through and around the wheels, as you are suggesting, but also influencing the air flow over the front wings. They interpreted this as constituting a moveable aerodynamic device since the uprights move when the steering wheel is turned.

I found that ruling a bit puzzling since ALL brake ducts influence the aerodynamics of the car!

Every team out there uses brake ducts that are carefully studied by both CFD and in the wind tunnel in order to minimize any negative influence to the airflow around the tires, and ALL of them have scoops and brake enclosures that actually reduce the aerodynamic drag within the wheel profile - in actual fact, making them an "aerodynamic device".

It is the holes in the hub itself through which some of the cooling air flows that the FIA didn't like and had them plug, which is even weirder ( it wasn't the brake ducts themselves that they didn't like) - while Red Bull is the only team that uses them at the moment, cooling holes in hubs have had extensive use in the past, and the FIA never questioned their legality.