long wire antenna
in [Repair]
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From: Arfa Daily on 8 Mar 2010 20:53 "Phil Allison" <phil_a(a)tpg.com.au> wrote in message news:7vj3h1F7nuU1(a)mid.individual.net... > > "Arfa Daily" > >>> It's not unlike a wing. Almost any surface flat on the bottom and curved >>> on the top can produce lift. >>> >> >> So how come a symmetrical wing, such as might be found on a stunt plane, >> still flies, and most asymmetric wings fly quite happily upside down ? >> :-) >> > > > ** I ask people who *think* they know how a plane flys that same Q. > > Stumps them all the time. > > Goes to show how simple explanations are often highly flawed. > > > > ..... Phil > > I saw an interesting dissertation on this some time back, which put forward a much more complex but better believable theory as to how a wing flies. I don't really remember the details, but it relied heavily on the wing's angle of attack into the air, to produce the pressure differential, and hence lift. I seem to recall that it was the opposite way round from the 'conventional' teaching of increased speed of the air over the top of the wing reducing the pressure, and that this theory had the attack angle causing compression under the wing, thereby increasing the pressure to produce lift. I do, however, remember it saying that air has no 'intelligence', and just because two previously adjacent molecules became divided above and below the wing, there was nothing to say that they had to form back up in the same way as they left the back edge of the wing, which would require the air to move faster over the longer upper surface. I believe it did say that the air actually does travel faster over the curved face of the wing, and that the fact that it does, does produce a reduction in pressure. However, this reduction is small, and only contributes a very limited amount of lift, compared to the main mechanism that's at work. Arfa
From: William Sommerwerck on 8 Mar 2010 21:00 > I saw an interesting dissertation on this some time back, which put forward > a much more complex but better believable theory as to how a wing flies. I > don't really remember the details, but it relied heavily on the wing's angle > of attack into the air, to produce the pressure differential, and hence > lift. I seem to recall that it was the opposite way round from the > 'conventional' teaching of increased speed of the air over the top of the > wing reducing the pressure, and that this theory had the attack angle > causing compression under the wing, thereby increasing the pressure to > produce lift. I do, however, remember it saying that air has no > 'intelligence', and just because two previously adjacent molecules became > divided above and below the wing, there was nothing to say that they had to > form back up in the same way as they left the back edge of the wing, which > would require the air to move faster over the longer upper surface. I > believe it did say that the air actually does travel faster over the curved > face of the wing, and that the fact that it does, does produce a reduction > in pressure. However, this reduction is small, and only contributes a very > limited amount of lift, compared to the main mechanism that's at work. I see your reasoning, but I don't think it's right. If the air near the surface of the wing did not travel faster over the top of the wing, there would be a buildup of air at the front. And let's not forget that little experiment where one blows over the top of a strip of paper, demonstrating, Bernouilli's Law. Of course, this isn't to say that there is /only one way/ for a wing to produce lift. But I don't want to get involved in this. Again, the point I was making has been completely missed. What else is new?
From: Rich Webb on 8 Mar 2010 21:12 On Tue, 9 Mar 2010 01:53:39 -0000, "Arfa Daily" <arfa.daily(a)ntlworld.com> wrote: >I saw an interesting dissertation on this some time back, which put forward >a much more complex but better believable theory as to how a wing flies. It's not really that complex. Didn't you ever, as a kid, hold your arm out the car window with your hand flat and "fly" it up and down as you changed the angle of attack? That's really all that's necessary. An airplane could fly (if not very efficiently) with wings made from flat sheets of plywood. -- Rich Webb Norfolk, VA
From: AZ Nomad on 8 Mar 2010 21:29 On Mon, 08 Mar 2010 21:12:26 -0500, Rich Webb <bbew.ar(a)mapson.nozirev.ten> wrote: >On Tue, 9 Mar 2010 01:53:39 -0000, "Arfa Daily" ><arfa.daily(a)ntlworld.com> wrote: >>I saw an interesting dissertation on this some time back, which put forward >>a much more complex but better believable theory as to how a wing flies. >It's not really that complex. Didn't you ever, as a kid, hold your arm >out the car window with your hand flat and "fly" it up and down as you >changed the angle of attack? That's really all that's necessary. An >airplane could fly (if not very efficiently) with wings made from flat >sheets of plywood. All you've got there is an inclined plane. You aren't creating lift. Try it without the car.
From: Rich Webb on 8 Mar 2010 21:47
On Mon, 08 Mar 2010 20:29:02 -0600, AZ Nomad <aznomad.3(a)PremoveOBthisOX.COM> wrote: >On Mon, 08 Mar 2010 21:12:26 -0500, Rich Webb <bbew.ar(a)mapson.nozirev.ten> wrote: >>On Tue, 9 Mar 2010 01:53:39 -0000, "Arfa Daily" >><arfa.daily(a)ntlworld.com> wrote: > >>>I saw an interesting dissertation on this some time back, which put forward >>>a much more complex but better believable theory as to how a wing flies. > >>It's not really that complex. Didn't you ever, as a kid, hold your arm >>out the car window with your hand flat and "fly" it up and down as you >>changed the angle of attack? That's really all that's necessary. An >>airplane could fly (if not very efficiently) with wings made from flat >>sheets of plywood. > >All you've got there is an inclined plane. You aren't creating lift. > >Try it without the car. The saying goes something like: with enough power, you could fly a brick. The lift comes from the angle of attack. -- Rich Webb Norfolk, VA |