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Last Post 07 Aug 2014 02:35 AM by  toy4speed
Largest legal rear spoiler in SM
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toy4speed
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Posts:117


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06 Aug 2014 12:44 PM

    Hi All, I've been running a my old DSP legal rear spoiler on my now SM Supra for several years, and been trying to determine how large I can build the rear spoiler.  DSP has 10" in height, from bodywork limits, and I was thinking of making it higher, but there is no discussion of spoilers in the SM rules.  I will eventually go to a wing, but for now, wanted to tinker with spoiler design till time and finances allow a wing design.  Rear wings in SM allow 8 sq feet in area, that's quite a bit more than my current spoiler.  If I added a gap at the bottom of my spoiler/body interface, extended the height of the spoiler, to say...14 inches, could that fall under a definition of a wing? 

    Have some time before Nats, just looking for some discussion/advice.  Thanks!

    Don

    FritzSpeed
    New Member
    New Member
    Posts:44


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    06 Aug 2014 04:13 PM
    Don,

    My understanding of 16.2 is that you would be limited by 15.2.I.2.b which is the 10" height that you reference. Based only on my limited knowledge of aerodynamic principles, I would think that raising a spoiler above the rear deck would reduce its effectiveness as a spoiler without providing the added downforce of a real wing.
    That said, the wing curvature and angle of attack do not factor into the surface area equation, so as long as you adhere to all of the rules regarding wing width, position, surface area, mounting and end plates, it seems like it would be possible to make your spoiler into a flat, steeply pitched "wing" that conforms to the rules. I would keep the 10" spoiler until you can install a good low speed, high downforce wing.

    Joe
    racingfool
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    Posts:177


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    06 Aug 2014 05:56 PM
    Posted By toy4speed on 06 Aug 2014 12:44 PM

       If I added a gap at the bottom of my spoiler/body interface, extended the height of the spoiler, to say...14 inches, could that fall under a definition of a wing?  

    Yes, in my opinion.

    In the spoiler rules it says,

    The spoiler may not function as a wing.

    If you want to run a spoiler it's 10" max.

    If you have a gap under the spoiler it becomes a wing and can be 8 sq ft.

    Which would be better? Mounting an 8 sq ft rectangle in a spoiler position with 1/4" gap...

    Or mounting that same 8 sq ft rectangle at a 45 degree angle with the trailing edge 6 " above the roofline?


    toy4speed
    Basic Member
    Basic Member
    Posts:117


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    07 Aug 2014 02:35 AM
    Ok, looks like its a SP rear spoiler at least for rest of this season. Maybe next year I'll visit the rear wing idea again. I just thought that since SM seems to allow much more "creativity" with performance mods, and monster wings are allowed, some allowance of the SP spoiler rule would exist. I guess since the SP spoiler was originally deemed as an appearance item, with no significant aerodynamic performance advantage (never understood that), it wouldn't fit into the SM standards.

    Yeah, everyone says gotta get the biggee wing thing, but tough to budget that in right now.

    Appreciate the feedback. I'm trying to keep within my rules of no major changes during the last month before Nats. Minor adjustments, maintenance, but major mods, untested, just before Nats never has worked well for me. Just working on the driver

    Don
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