Sorry, I thought you were serious, it seems you are trolling.
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Sorry, I thought you were serious, it seems you are trolling.It's interesting what you write. Now I am thinking of building such model from chipboard or plywood. In this case, tilting the nose down should not cause a big problem, because "fuselage" is just a flat plate. I wonder if something like this will glide if I drop it from the tenth floor.
After all, how could you fly upside down if AoA didn't matter?.
The shape of the wing - its cross sectional profile - on my Ercoupe, combined with its angle of incidence as set on the fuselage, means that it goes from no lift to considerable lift with a small amount of change in angle of attack. When properly rigged - and many out there are not - you can go down the runway at full power and the airplane will sit there moving fast, with its wheels on the runway. Pull back on the wheel just a little and .. Zoom! Up you go.
The wing can be flat, but the leading edge should not be square - ever. Boundary layer separation ensues much faster with 'flat' leading edge. Trailing edge should be tapered.I didn't think it didn't matter. I even read about some plane that had the ability to change the AoA to make it easier to take off from the carrier. But I thought convex is always necessary. Smaller on faster planes, larger on slower ones. In other words, I thought "flat convex airfoil" was the only type of airfoil. When it comes to upside down flights, I thought it was possible because of the powerful engine (same as a rocket can fly "upside down.") But if you are right, the wings can be completely flat and such a structure has some lifting force. I have to check on the model. Of course, the words about the "tenth floor" are a simplification. I mean great height above the ground (not in the city center ...) That's actually all for now. I thank those who wrote the things that were interesting to me.
To compare to the aviation industry standard of a half house brick. Any human development that doesn't stay in the air longer and/or cover more distance in a horizontal plane than a hand thrown half house brick is a step backwards. Or to add to the millions of internet events that never happened.I realize you're not a pilot or a engineer.
But I wonder what you thought process is for starting out the test with the model in a vertical dive ?
That is how a wingsuit operates. There is no reason it can't be analysed with the same rigor as other forms of aeronautics, such as groundhogs.I realize you're not a pilot or a engineer.
But I wonder what you thought process is for starting out the test with the model in a vertical dive ?
I realize you're not a pilot or a engineer.
But I wonder what you thought process is for starting out the test with the model in a vertical dive ?
I know it's a bit confusing, but both statements are actually true: curvature (camber) IS necessary for lift, AND lift is produced by deflecting the air downward, NOT by the so called "Bernouli effect"... and it turns out my teacher at school was probably right (here the author also writes that the wing must have a curvature, because then the air flows faster over the wing and this reduces the pressure). And earlier on this forum other people wrote that this is - if I understand correctly - a misconception about how planes fly.
The purpose of the curvature is to allow the airflow to stay attached in laminar fashion to the wing top surface as the angle of attack increases as long (in time) and as far back (in distance) as possible with increasing angle of attack before it detaches into turbulent flow (Stall). This requires that the airflow not be asked to turn too sharp a corner, as that is what will detach it. Your flat board with it's square leading edge can't assume much angle of attack before the air just can't bend around the corner any more.
The higher energy airflow over the top surface is what deflects the recombined air at the trailing edge at a downward angle, creating downwash and lift. This only happens at a positive angle of attack for a symmetrical airfoil where the top flow path is longer than the bottom one. If AoA is zero, both flowpaths are the same, there is no downward deflection of the air leaving the trailing edge, and no lift is generated.But difference in airspeed over the wing and under the wing was really not necessary at all?
Make sense?
I curvature (camber) IS necessary for lift, .
Ed Heiniman had a student working on what airfoil to use for the A-4. The kid went off and Heiniman did not hear from him for a number of weeks. He went to see what was going on and found the student doing detailed wind tunnel studies on multiple airfoils, trying to figure out which cross section was best, and getting rather confused. He had a number of different airfoil sections he had run tests on and could not figure out which one was best
Heiniman took a piece of ordinary plywood, cut it to the shape of the A-4 wing, rounded off the leading edge, and had the student run wind tunnel tests.
"How much difference in the results in that plywood and the other sections you tried?" asked Heiniman.
"Not much at all." replied the student.
"Well, there ya go." replied the great designer.
The important part is that Heiniman rounded off the leading edge - at a normal angle of attack, all lift is generated forward of the wing's maximum thickness. Aft of that point, the wing exists only to reduce pressure drag.
Cheers,
Dana
I don't understand that. What is "normal" AoA? Where does a lift come from? If that plywood had zero AoA, there was no lift (I think)? If this plywood had non-zero AoA, the airflow over the plywood should be "disturbed" (I think?)
(I would add that the problem is probably not that you write unclearly, but I have to translate it from English into my native language, and aerodynamics is not a conversation about walking in the park with the dog. So - I can sometimes have trouble understanding certain sentences.)