Rear Downforce Wing

Notes.
The forward splitter may need to be less area. Once the full scale model is cut out, it can be trimmed back if needed. Easier to take away than to put back.
The diffuser can possibly be started more forward. Wait for the full scale mock up to determine location.
The total device will consist of 2 separate pieces. The forward flat section with incorporated splitter from the middle of the transmission to the front of the rear wheel well opening, and the rear diffuser section starting at the rear of the forward flat panel section to the rear bumper. The floor of the forward piece will flow into the diffuser with as little disruption of the surface as possible. Smoothness of all surfaces is of major importance to get the best performance out of this device.
 
The splitter will serve 2 main functions. Maybe 3.
The main function will be to split the air that will be trying to get to the underside of the flat panel. Another function will be more of a safety issue. The splitter will catch some of the fluids in the event of a major engine failure, and direct them to the sides of the car, ahead of the rear tires.
The third function may be some added downforce, but due to the location of the splittler under the car, that would be very slight.
The planned ground clearance is 4 inches at rest, turning to 3 inches on the top end.
 
Front section will start from a 6' x 6' piece of sheet aluminum.
Thickness...1/16".
 
After more thinking, and looking at the bottom of the car for about an hour, the design has changed. The flat section will encompass from the front crossmember on back to the point where the floor will angle upward for the diffuser. The width of the device will be frame width.
Present ground clearances are 6" at the front crossmember and 10" frame to ground in front of the rear tire.
The flat section will start 2" lower than the front crossmember (4" off the ground), and will be 5" lower than the frame in front of the rear tire (5" off the ground).
With downforce pulling the body down at speed, 1" in the front and 1" in the rear, that will leave 3" of ground clearance at the front and 4" of ground clearance in front of the rear tire.
This flat section will act as a gigantic diaper that will catch engine bay fluid leaks, or pieces of rod and camshaft. Let's hope it only catchs little drips here and there, and not my crankshaft.
 
Ground clearance to the frame, behind the front tire is 8.5".
2 Dzus at front of front crossmember.
4 Dzus along outside of each side frame rail between front and rear tires.
2 Dzus along each front leg of X frame. Outside of rails.
3 Dzus along each rear leg of X frame. Front one outside of rails. The remaining inside of rails.
A rear mounting crossmember will need to be fabricated, located in front of rear tires, between frame rails. 4 Dzus equally spaced along this crossmember. This crossmember can have a driveshaft safety loop incorporated into it.
 
The sides of the flat section will be angled up and inward, and the edges of the sides will be tucked just outside the body pinch welds at the bottom of the rocker panels.
The plan is to lower the rear end at least 1/4 inch after fender lip mods. The dead weight alone of this ground effects and diffuser device may drop it down another 1/4".
Next step, start mounting some Dzus tabs.
 
It starts.
 

Attachments

  • IMGP2466rs.jpg
    IMGP2466rs.jpg
    87 KB · Views: 275
lookin forward to the update and get some input on improving handling on our bricks but then again most of you guys are after a different kind of handling
 
I think instead of trying to draw what this is going to look like, I'm just going to post pics of the progress. This is turning into a 'design on the fly' project. My first concept has taken a dive. The latest design will be much easier to fab and mount, and should be more effective.
 
Mocking up the front section of the flat panel.
 

Attachments

  • IMGP2475rs.jpg
    IMGP2475rs.jpg
    90 KB · Views: 252
  • IMGP2471rs.jpg
    IMGP2471rs.jpg
    90.3 KB · Views: 236
  • IMGP2470rs.jpg
    IMGP2470rs.jpg
    88.7 KB · Views: 280
More pics.
The last picture shows the panel in the planned position.
 

Attachments

  • IMGP2481rs.jpg
    IMGP2481rs.jpg
    91.9 KB · Views: 245
  • IMGP2478rs.jpg
    IMGP2478rs.jpg
    91.4 KB · Views: 239
  • IMGP2482rs.jpg
    IMGP2482rs.jpg
    91.1 KB · Views: 252
I like Pete's mounting style. I wonder how much the fins help the car stay straight?
 
Testing this coming weekend at Barona. James (Squid4life) was kind enough to let me borrow his rear deck lid w/Ed Quay wing. It's a typical drag type wing mounted off the end of the rear decklid. The design doesn't allow for much, if any, angle change of the wing. We'll be setting it up as intended by the wing manufacturer.
Saturday, I'll be making two runs to get a baseline without the wing, then we'll switch decklids and make a few more test runs.
The boost control curve will be aggressive on the top end. By all rights, it should blow the tires away about .5 - 1 second before the finish line (1/8 mile). It will be interesting to see what sort of improvement we might get.
Anyone want to make any predictions?
 
:eek:
I would have to predict a big grin, or an extreme ass pucker when the tires say "see ya !"
 
Top