Timeline for How much lift do supercritical airfoils produce?
Current License: CC BY-SA 4.0
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| Oct 28, 2019 at 2:21 | comment | added | Robert DiGiovanni | @Zeus this is why the Reynolds number formula may need a Mach factor built in. At lower Mach, "conventional" airfoils benefit from accelerated airflow (circulation) over the top, but, as aircraft speeds increased, began to encounter the shockwave "barrier". Without taking Mach into account, at lower airspeeds, "supercritical" lift to drag performance (especially while maneuvering and actively changing AOA) is rather poor, particularly with sharper leading edges. I am hoping this leads to better "when do we fully retract slats and flaps" SOPs. | |
| Oct 27, 2019 at 23:55 | comment | added | Zeus | "...while conventional airfoils must struggle to keep speeds subsonic" Must they? They should, primarily for the sake of lower drag, but strictly speaking the OP didn't ask about drag ;) Given the same conditions (which we must assume for fair comparison), local speeds (or rather, peaks) will be higher on the conventional airfoil, and the question is (indirectly) how that will affect lift. I don't think it's clear from the paragraph; some may even conclude that speeds are lower... | |
| Oct 27, 2019 at 14:28 | history | edited | Peter Kämpf | CC BY-SA 4.0 |
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| Oct 27, 2019 at 13:06 | comment | added | Robert DiGiovanni | The larger leading edge seems to universally improve higher AOA characteristics, particularly Clift/Cdrag vs Alpha, where many of the sharper leading edge designs begin to fall off at around 5 degrees! Looking at even some of the early Gottingen thick airfoils, amazing that their lift to drag was very favorable (So to save drag use a smaller Gottingen). | |
| Oct 27, 2019 at 13:02 | comment | added | Robert DiGiovanni | Peter Kampf, appreciate your continued refinements. Perhaps the question would be better phrased as "which wing produces more lift at a given speed" as this has become an incredibly relevant subject for newer airliner wings and could lead to improved procedures for when to apply slats and flaps. | |
| Oct 27, 2019 at 10:44 | history | edited | Peter Kämpf | CC BY-SA 4.0 |
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| Oct 27, 2019 at 5:31 | history | edited | Peter Kämpf | CC BY-SA 4.0 |
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| Oct 27, 2019 at 1:24 | comment | added | JZYL | @RobertDiGiovanni Modern super-critical airfoil can be thin and have large stall AOA (at least in non-icing, contamination-free condition). | |
| Oct 26, 2019 at 20:56 | history | answered | Peter Kämpf | CC BY-SA 4.0 |