Start at the NACA 4-digit airfoil generator and plug in some numbers. I don’t know if it originated from a NACA profile, and I’ve tried to find a NACA shape that’s the same, but I can’t find an exact match because it has more camber.įor fun, I’ll plot a wing that looks similar. Multi-element wings can also benefit from more thickness.įirst I want to give a shout-out to 9 Lives Racing who makes a very strong, economical, and proven wing. The author suggest around 16-18% thickness as being ideal. A thickness of around 12% is quoted as being best for flow separation, but a thicker wing doesn’t create much more drag at car speeds, and could be better when run at a high angle of attack.Moving camber rearward generates more downforce, but further forward is more efficient for low-drag, low-angle applications.More camber creates more downforce, but too much and you get separation underneath at the trailing edge.McBeath discusses these form factors and how they allow a wing to generate more downforce. So, a NACA 6312 wing has 6% camber, the max camber occurs at 30% of the chord length (from the front), and the thickness of the wing is 12% of the chord length. In NACA 4-digit wings, the first digit is the camber as a percentage, the second digit is the location of camber in relation to the chord length, the third and fourth digits are the percent thickness of the chord. In Competition Car Aerodynamics,, Simon McBeath frequently uses the NACA wings as examples, such as the NACA 6312. When using the Airfoil Tools calculator, I set the values to 200,000, 500,000, and 1,000,000, which are realistic Reynolds numbers for most cars and wings. Doubling the speed doubles the Reynolds number. For example, a wing with a 10″ chord that is traveling through the air at 67 mph, and at 68-degrees F has a Re number of around 500,000.
The airfoil tools calculator has values that can be used to simulate Re numbers (car speeds). The shapes are more efficient at high speed (or underwater). What’s important is that wings generally work better with more resistance. At 60 mph, there’s more resistance it’s almost like moving your hand through water. At 5 mph, you can put your hand out the window and move it back and forth with little resistance. The Reynolds (Re) number can be thought of as a resistance number. Cars don’t go nearly as fast as planes, and so the ideal shape of a car wing is different, and optimized for Reynolds numbers on the lower side of the spectrum. Naturally most of these wings are designed for airplanes, but some have been used on cars (upside down) to create downforce.
It serves as a catalog of existing airfoil shapes, and allows you to compare them, simulate different speeds and angles of attack, and draw and plot your own wing shapes.
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