Fundamentals of Lift 3: Airfoil Shapes

[@carmelpule1]

There are many philosophies contributing to the reasons for LIFT in a wing, propeller, turbine blades, basically, all based on the Newtonian dynamics of fluids with their other sealing, shearing,, cavitation, boiling, and aeration, thermodynamic effects, and characteristics. Let us have a look at CIRCULATION around a wing, as in other contributions I dealt with the Newtonian and Bernoulli effects. It is interesting to mention that any sail profile or wing airfoil, needs to operate in the angle between the direction of motion of the boat or the wing, and the APPARENT WIND into the leading edge. To avoid turbulence, the apparent wind should enter a "thin" sail, or a " thin" airfoil parallel with the leading edge, and the change of direction of the fluid would come later on. With a thick sail, or thick wing, the processing zone at the leading edge would benefit the flight accelerating time above and below the wing. Let us deal with CIRCULATION around the airfoil, rather than the details of the velocity and pressure fields in close proximity to the surfaces of the wing. Let's look at the bigger voluminous picture of circulating fluid masses The easiest manner to see the circulation around the airfoil of a high aspect ratio wing is to first study the helicopter in hover mode, where the fast accelerated central downstream flow of the main rotor and the slower decelerated upstream flow, outside the main rotor, forms a circulating doughnut ring., It is, in fact, an amplified extension of the dumping brought about by the wingtip vortices of the main rotor. This circulation must occur as the world is not big enough for helicopters and aircraft wings to keep robbing air from high altitudes and dumping it down to lower altitudes. Circulation is only a return path of displaced air. . If a helicopter, from a hovering mode, tilts and goes into a forward motion, this doughnut with circulation will still exist and the front leading part and the rear trailing part will be subjected to the Magnus effect, where the leading circulation will uplift, while the back circulation will down lift. The side circulations will be exactly the same as a pair of wingtip vortices on a conventional wing, with their axis in line with the forward motion. Since the rear Magus effect is producing a down lift, the back part of the circulating doughnut can be discarded, while the contra-rotating pair of side vortices with their axis moving in the direction of the forwarding motion, would still dump the air mass into the center of the modified forward-moving doughnut, where the front circulation can be obtained and continuously sustained by doing away with the main rotating rotor and replacing it with a forward-moving plate having a large angle of attack, with the lower surface producing a compression zone will slow down the moving air while the top surface will create a suction to speed up the airflow and the circulation around the airfoil will remain sustained, existing to complement the pair of vortices at the wingtips. It is the dumping of circulating air mass behind the wing or the central downstream flow of the air mass by a forward-moving, or hovering helicopter "doughnut shape with circulation", that creates lift. AS LONG AS THERE ARE ACCELERATIONS AND DECELERATIONS PHASES AND ZONES ALONG THE TRAJECTORY/PATH OF THE CIRCULATION. What is accelerated and centrally dumped down under the main rotor of a hovering or a forward-moving helicopter, is exactly the same Newtonian philosophy as what is dumped behind the trailing edge of a moving wing and those pair of vortices at the wingtips. That inconspicuous doughnut shape, with a circulation, exists in a hovering or forward-moving helicopter as much as it exists in a moving wing, where, due to its forward motion becomes phased in time/ space with the moving doughnut with circulation. The wing leads the central part of the doughnut. The back part of the doughnut shape is left far behind and is replaced by the back stabilizer of an aircraft.

[@christopherknee5756]

I would love to hear your comments on the Spitfire wing. Was it actually any good? Also the Bf-109 wing with the LE slat gizmo. Which was better?

[@LightAndSportyGuy]

Well, they guys who designed the Spitfire should have known what they were doing - I suspect that it was pretty good. And as to which was better, don't have a clue - way above my pay grade. 🙂