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LeGrand Mk 18 : Full-Frontal Aero Aug 19, 2010

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At our last two events, we felt some understeer and possible lift at the nose of our LeGrand. This led us to believe that the rear wing is certainly working to keep the rear wheels planted at speed and that a front wing was in our future.

We don’t have the budget for custom elements that cost $1000 a piece, so we came up with a game plan that used an off-the-shelf carbon fiber element from a “universal wing,” some scrap aluminum, and a sheet of half-inch hardwood plywood.

The APR wing element we purchased from Ciro Design was formed in a silver carbon weave. That clashed with the rest of the car, so we gave it a quick spray of black paint. The element itself is quite nice; it weighs about 2 pounds and appears to be strong enough to take the hit of a pylon. The kicker is that it was $100 shipped to our door.

We made a new splitter out of the plywood, extending it about 1.5-inches. This gave us enough space to mount some brackets that we fashioned out of .090-inch 6061 T-6 aluminum. The whole assembly weighs under 8 pounds.

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Comments

Gonzo_Bmod:

Very Nice. Check out the airflow with some tufts. If you find it stalls, go to Lowes, buy strips of aluminum 90 degree bend in one or two widths and use double sided tape to attach as a Gurney lip. It might help keep the flow attached at steeper wing angles increasing the downforce.
Aug 5, 2010 8:34 p.m.

CamaroKeith:

This is really making me want to buy one of these…
Aug 16, 2010 5:23 p.m.

Fireba11s:

Great start, but it will produce a lot more downforce if you drill another set of holes in the end plates and move the wing up to the top of the end plates. The wing produces low pressure on its lower surface, but it also produces low pressure on the upper surfaces of the splitter and nose because they are so close together. The flow through that slot is a lot like the flow through a carburetor venturi: no net force in any direction. More separation will reduce that destructive interference. While you are at it, you may as well slot the aft bolt hole on each side for some adjustability. There is some simple and effective guidance about using Gurney flaps for low speed racing in the aerodynamics chapter of my new book, Think Fast: http://thinkfastbook.com If GRM is up for it, I would be glad to write a race engineering Q&A column. Neil
Aug 16, 2010 9:47 p.m.

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