Spoiler construction

[javajoe79]

 So in the rule book, approach #1, you are allowed to fill the horizontal gap between the body and the leading edge of the spoiler up to the centerline of the rear axle. On the firebird that space is nothing in the middle then extends all the way forward to where the stock wing ends. I am assuming that would be fine. I can't find any pictures of the same car with a spoiler like that. Anyone know of any?

Our car has this style rear wing.   

[gkabbt]

Chris, I don't know if this answers your question but here are a couple of pics I got a few years ago of the MacDonald and Pitts 300+ 1999 Firebird.
Looks to be the same factory spoiler that you have so it probably would be sufficient.





Hope this helps,

Gregg

[dw230]

If the spoiler is OEM, unmodified, it will be OK from Production to Altered classes. One caveat, is that a SPOILER has a single aero surface, air going under the rear lip, even if OEM, is considered a wing and not allowed in some classes.

Check with your committee chairman if this is a SCTA question for El Mirage or the salt. If for another venue, never mind.

DW

[javajoe79]

Yes it's the same as that car above. Couldn't remember if that car had a spoiler on it or not.  What I am talking about is adding a sheet metal spoiler as described in the book 4.CC.8 approach 1 Figure 9

 Was hoping for another same year firebird with a fabricated spoiler like that. Anyway I will run it by Lefevers.

[Sumner]

I'd think any deviation from what is there stock would put you complying with the rule book's definition of a spoiler and where it can and can't be. 

Personally in a lot of cases where you don't need the downforce of one (which usually also is accompanied by more drag) the main benefit of a spoiler is that you can then add spill plates and those I would make to the maximum dimensions of the rule book.  Also where the spoiler is located will let you make them larger in some cases and still be within the rules.  The spill plates are going to add to your center of pressure and can be actually added in twice if you use this method of determining your cars center of pressure...

http://1fatgmc.com/car/14-Hooley/14%20-%20hooley-construction-2014-2.html

Getting the CP location as far reward of the CG can pay big dividends in having a car that isn't inclined to spin.  In Hooley's case the spoiler had been there to gain the advantage of the increased CP the spill plates give the car.



Now it is the wing that allows us to really improve the CP by allowing the verticals.  As time goes on we will try and use the wing also more and more for downforce as we are about the limits of adding weight to the car,

Sumner

[javajoe79]

Great info as usual Sumner. I don't think we will need much downforce as this thing will be heavy!!  I will be maximizing spill plate size. Spoiler will be adjustable and with gurney flap option. Also would like it to freely flip up in case of a spin to help keep the car on the ground 

[Sumner]

.. Also would like it to freely flip up in case of a spin to help keep the car on the ground 

Consider putting in a roof flap/flaps.  You can see the one above that Hooley installed on the car. 

Sumner

[javajoe79]

We have a pair of flaps but there's really only room for one. So we will have that too.

[wheelrdealer]

Chris:

I built one  for gen two Camaro to  what I think the maximum rules says. The spoiler can be set for +5, 0or -5 degrees. What I wanted was what Sumner said as much spill plate as possible. It has not passed  tech but I think  it will. I also wanted the deck lid to open with  out a lot of trouble. There are 4 vertical stabilizer turn buckles and two spill plate turn buckles to brace and make sure they stay vertical.

BR

[javajoe79]

That is what I am planning. Looks nice!  Did you use 1/8" for the spill plates?

[wheelrdealer]

Yes, the center plate is  actually an Ed Quay piece that I shortened to meet the 10" chord limit. The side plates have tabs the mount on the underside of  the trunk with .250"  button heads on top of the deck. I used  the old GM panel fitting to my advantage. Was able to adjust  the trunk where the 1/8" spill plates fit  in the gap. I have a drilled angle mounted underneath for a Gurney Flap if there is a need.

BR

[revolutionary]

I found this pic of a spoiler for similar car. Thoughts?

[revolutionary]

[Sumner]

....What I wanted was what Sumner said as much spill plate as possible..

Was there a reason you slopped the spill plates down?  I think they could of been higher in the front giving more area that would help the CP.



The spill plates on the car above could of also been made larger.  It is tempting to change the shape to make them more pleasing to the eye but I'd make them as large as the rules allow and the hell with looks,

Sumner

[javajoe79]

I found this pic of a spoiler for similar car. Thoughts?

Thinking sort of like this but hinged at the point where the stock spoiler ends. I have an email in with Lefevers also. Pretty sure how I have it envisioned in my head will work well and be legal. I agree with Sumner on keeping the spill plates at max size and I think they will also look fine on this car. At 300 mph who cares what the spill plates look like?