- 16 Apr 10, 19:47#195934
I've looked at every online photo and diagram of McLaren's F-duct I can find and I can't make it work. I can't grasp how this ducted air is causing the wing to stall.
I'm an experienced pilot so I'm fully aware of how and why a wing stalls* and what the consequences of a stall are. That only compounded the problem because I know that a stall also necessarily causes a noticeable vibration as laminar flow turns turbulent and buffets the aerofoil. Part of what was troubling me is that this vibration should be being felt by the driver and could potentially contribute to the wing's structural failure. Even without structural failure but perhaps as dire, buffeting would make the rear end twitchy and reduce the driver's margin of control. In other words, there are potentially catastrophic negative consequences to the stalling of the wing but nowhere have I heard this remarked to.
Today, it occurs to me. I was looking at photos of Ferrari's take on the F-duct and realised there likewise would be a reduction in downforce if instead of inducing a stall, the ducted air were simply accelerated over the top of the rear wing. This effectively would lower the dynamic air pressure over its top, reducing any pressure differential between the two sides and, in turn, reducing lift. All without the negative consequences of a true "stall."
Is this how the F-duct actually functions? Have I been suffering brain-lock because of their mis-use of the term "stall?" Is "stall" an oversimplication someone dreamt up to save the trouble of explaining how it is they're nullifying the wing's Bernoulli effect?
If I'm wrong, please show me where.
*Resulting relevant wind produces an angle of attack in excess of the airfoil's critical angle, causing boundary layer separation
I'm an experienced pilot so I'm fully aware of how and why a wing stalls* and what the consequences of a stall are. That only compounded the problem because I know that a stall also necessarily causes a noticeable vibration as laminar flow turns turbulent and buffets the aerofoil. Part of what was troubling me is that this vibration should be being felt by the driver and could potentially contribute to the wing's structural failure. Even without structural failure but perhaps as dire, buffeting would make the rear end twitchy and reduce the driver's margin of control. In other words, there are potentially catastrophic negative consequences to the stalling of the wing but nowhere have I heard this remarked to.
Today, it occurs to me. I was looking at photos of Ferrari's take on the F-duct and realised there likewise would be a reduction in downforce if instead of inducing a stall, the ducted air were simply accelerated over the top of the rear wing. This effectively would lower the dynamic air pressure over its top, reducing any pressure differential between the two sides and, in turn, reducing lift. All without the negative consequences of a true "stall."
Is this how the F-duct actually functions? Have I been suffering brain-lock because of their mis-use of the term "stall?" Is "stall" an oversimplication someone dreamt up to save the trouble of explaining how it is they're nullifying the wing's Bernoulli effect?
If I'm wrong, please show me where.
*Resulting relevant wind produces an angle of attack in excess of the airfoil's critical angle, causing boundary layer separation
"I'll bet ya a hundred and five thousand dollars you go to sleep before I do."
--Dobbsie
--Dobbsie
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