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4

No, it's not possible to have them simultaneously. Here's a proof by contradiction: Assume that there are two points on the airfoil that have constant pitching moment, located at $x_0$ and $x_1$, each having constant moments $M_0$ and $M_1$, respectively, and that $\frac{\partial{M_0}}{{\partial\alpha}}=\frac{\partial{M_1}}{{\partial\alpha}}=0$ (which make ...

1

It is amazing how ingrained into the psyche of many aviation enthusiasts, even today, is the issue of lifting the plane "as birds" when the issue of propulsion against drag is predominant as speed increases. So, reduction in drag becomes the key issue. Indeed, a flapping wing is perfect for a relatively slow, lightly wing loaded bird as it "...

1

Several things come to mind: Probably not. A flapping wing is only producing thrust during half its operating cycle (except hummingbirds and insects, who's wings generate thrust in both directions when hovering) so there is energy wasted in the wing's recovery cycle in normal forward flight. It might be better for the bird to keep its wings "fixed&...

1

In short, the answer is No. For many centuries, many proto-aeronautical engineers believed that the secret to manned flight would be found in complex flying machines that mimicked the flapping techniques of birds. These ornithopter designs were doomed from the start. Aside from the obvious issues involving strong, rigid, durable, and light materials, there ...

0

Likely no but let's see The relevant research study can be found here. In this study, it was shown that for some insects, the induced power can be twice the ideal value in hover, and can be even higher than this in forward flight. This is worse than possible with the fixed wing. From the other side, the same study says that flapping wings do not show ...

14

There are a few different ways. Probably the most low-tech and widespread is by marshaller guidance, which is a person outside the aircraft guiding the pilots by means of visual signals: The exact hand signals to use are defined by the ICAO, meaning that they are identical no matter where in the world you are flying. Most larger airport have some sort of &...

1

The 3 degree glidslope remains fixed relative to the earth, so a higher rate of descent will always be required to stay on the slope if you increase speed. Conversely, less rate of descent is needed at slower speeds. It just makes sense if you think about it, but if you need a practical demonstration try this: Draw a diagonal sloping line from corner to ...

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