Bolt-on Rear Wing
 

I am working on making a rear wing element that is attached via the rear tow hook mounts. My models show it being able to supply up to 300lbs of down force. It is fiberglass with a cord length of a foot, 69" in length, and the entire assembly should weigh less than 40lbs. I am wondering if this is something viable for autocross, and if so what class would it be allowed in. I am wanting to make changes to make sure that it will fit in a class.

I am planning on offering it in the normal and a controlled version. The controlled version has electric actuators that will control the angle of attack to apply force when you want it to on the track.
http://imgur.com/a/wRHQI

Here are pictures of it on the car:
http://imgur.com/a/I3nNd

300 lbs at what speed?

How is it gonna stay on?

That's at optimal angle of attack @ 100mph, with optimal airflow. It will never get this high. I also assume that the wing will have to shrink in size. It will stay on with the risers that will be built from aluminum honeycomb to reduce weight and still take the down-force.

Most popular autox classes for the twins are C Stock and STX. Both don't allow for aftermarket wings. Furthermore, most autox tracks don't exceed 2nd gear ~60mph. Not sure how effective/practical your wing is for autox consumers. Probably have better luck marketing to the track guys and or hard parkers.

I know that it will rarely see 100mph, but down-force is usefull accelerating out of corners and the like. I wanted it to be bolt-on for track days so my car won't look like rice the rest of the time. The price point, hopefully just under $1k was also geared towards function at the track.

I'm a mechanical engineer and I hate seeing the stupid wings and all in carbon fiber. This is a functional E423 airfoil design that works well at low speeds. I know it won't fit the standard stock-esque classes, but was hoping there was a "fun" class with some rules.

I was under the impression that in the STX class the wing had to be within the width dimensions of the car, in this case 69." Is there a limit on the height or how far back it sits?

No aftermarket wings in stx period. Hell, an frs with a brz wing isnt even legal.

Ok. Then what is the most common class that allows an aftermarket wing and what are the rules pertaining to it?

SM will allow depending on dimensions. E mod, for the hardcore, has hardly any restrictions

I like the idea. I'd be interested in more details

I found these rules in regards to street mod category, on a 2009 post.

L. Wings may be added, removed, or modified. Nonstandard
wings may only be attached to the rear deck/hatch area and may
not extend more than six inches beyond the widest part of the
bodywork on either side. The total area when viewed from the
top of the airfoil sections of all wings shall not exceed 15 square
feet. The area shall be computed by multiplying the width and
depth of the wing without regard to the curvature of the wing.
Any airfoil shadowed by another airfoil with more than six
inches between them will have its own projected area added to
the wing area calculation. There is no limit on number of elements.

This wing is only 5.75 square feet by those rules.

I am having a hard time finding current information like this in regards to the classes. If anyone here can help me I would greatly appreciate it.

Also, does the 6" rule apply to the the height of the wing from the top of the roof?

It looks like it'd snap off

2013 and draft 2014 rule book links. Allowed mods start somewhere around page 70 I think. Check the ToC

http://www.scca.com/solo/content.cfm?cid=44517

In Section 16. L for Street Modified it states:

Non-OE wings may only be attached to the rear deck/hatch area behind
the center-line of the rear axle.

Wings, and any component thereof, may not extend beyond the vehicle width, as defined by the outermost portion of the vehicle doors, less mirrors, door handles, rub strips, and trim. In addition, no portion of the wing or its components may be more than 6” forward of the rear axle, more than 0” beyond the rear most portion of the bodywork, or more than 6” above the roof line of the vehicle, regardless of body style. For convertibles and roadsters, the highest portion of the windshield frame will be considered the highest portion of the roof; however, a convertible or roadster utilizing a hardtop will use the highest portion of the hardtop as the roof line.

I could, with difficulty, mount the wing farther forward to appease the second highlighted part, but if the mounting location is truly as strict as the first part states then this design would never fit into the modified category. Am I correct in this assumption?

That's how I read it.