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#31
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Lift - Newton/Bernoulli ratio...
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Lift - Newton/Bernoulli ratio...
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Lift - Newton/Bernoulli ratio...
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Lift - Newton/Bernoulli ratio...
On Wed, 25 May 2011 01:21:09 +1200, Dave Doe wrote:
We're talking lift here mate - that's in the upwards direction! Do you know of any past or present figure other than me who uses the base chakra area muscle click (involuntary) as closure to a magickal working? Or for divination? I believe that Myrddin, one of the historical figures that the legend of Merlin may have been based on, did this false divination when he consulted his "little piggy" in the forest. That is, I think that his "little piggy" was his base chakra. Oh, I forgot to define the base chakra area muscle click or short period mulabhanda to those who don't know what a base chakra is. Basically the base chakra area is the perineum, or area between the genitals and the anus. I think in a chicken this is known as the pope's nose (correct me if that is some other area). The click or jerk or short period mulabhanda is a clenching of the muscles in this base chakra area. For a longer period mulabhanda the muscles are held clenched but for this click they are clenched and quickly released. David |
#35
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Lift - Newton/Bernoulli ratio...
On May 23, 9:31*pm, a wrote:
On May 22, 10:02*pm, brian whatcott wrote: On 5/22/2011 5:15 AM, Dave Doe wrote: Does anyone have any figures and references for about what ratio lift is produced by Newton's Laws and Bernoulli's Laws? I appreciate this is not a static figure - but say a yer average C-172, or perhaps a 737. I would hazard a semi-educated guess that lift is *primarily* produced by angle of attack (or deflection if you like) - Newton's Laws - and by a much lesser degree by Bernoulli's Law. *I would guess that Bernoulli's principle might create 20% of the lift a wing generates. *A friend believes it would be much lesser - about 5%. Think of it this way: Newton: force is proportional to the mass and its acceleration. In this context, the meaning is, to produce the aircraft's weight in lift i.e. upwards , an airmass has to move *with sufficent acceleration to provide that up force. Bernoulii: the mass of air flowing through a channel times its speed gives the same product even if the channel then narrows to a waist: the air mass has to flow faster, but its pressure drops.. In this context: air flowing in an airstream over a wing sees it bulging (or waisting) and so that it needs to speed up, and pressure drops over the upper wing. Arguments of this type can be used as evidence that 2/3 of the wing lift is produced at the upper surface, and 1/3 at the lower wing surface. The larger truth: air pressure drops over the upper surface of a wing, and increases over the lower surface of a wing, and the resultant downflow balances the lift on the wing. Brian W theories anyone here really believe there is no change in air density as if flows at speeds of a hundred miles an hour past an airfoil? The equation works well for water flow in pipes and around boat hulls. It does not do such a good job of predicting pressures along an airfoil. Stick with Newtonian Physics and the gas laws. The ideal gas law still applies. Compressing airflow does indeed complicate Bernoulli as do the density changes involved but Bernoulli still holds up. Both theories remain correct even with compressible flow. But you are correct in that the Newton explanation is FAR easier of the two for people to deal with and understand. The only caveat I stress to instructors when getting into the lift issue is that they NEVER explain lift using ONLY one theory without mention of the other, as student pilots, once exposed to the lift question will invariably find through a credible source that BOTH Newton and Bernoulli are correct and that each can explain exactly the same thing to the 100% point. Lift can be explained to death. The deeper one goes into the explanation the more complicated it can get. Denigrating Bernoulli due to changing density and airflow speeds causing compression factors is NOT the way to present lift. Bernoulli stands. It's the math that gets harder when you compress the flow that's all. All this can be avoided by simply explaining to students that lift results when an airflow is TURNED, and BOTH Newton and Bernoulli can be shown to cause the airflow to turn as lift is being produced. Circulation, density, vortices..........all part of it, but it's the turning of that airflow that produces lift force and BOTH Bernoulli and Newton are working equally to produce that force, only doing it differently. Dudley Henriques |
#36
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Lift - Newton/Bernoulli ratio...
In article
, Dudley Henriques wrote: On May 23, 9:31*pm, a wrote: On May 22, 10:02*pm, brian whatcott wrote: On 5/22/2011 5:15 AM, Dave Doe wrote: Does anyone have any figures and references for about what ratio lift is produced by Newton's Laws and Bernoulli's Laws? I appreciate this is not a static figure - but say a yer average C-172, or perhaps a 737. I would hazard a semi-educated guess that lift is *primarily* produced by angle of attack (or deflection if you like) - Newton's Laws - and by a much lesser degree by Bernoulli's Law. *I would guess that Bernoulli's principle might create 20% of the lift a wing generates. *A friend believes it would be much lesser - about 5%. Think of it this way: Newton: force is proportional to the mass and its acceleration. In this context, the meaning is, to produce the aircraft's weight in lift i.e. upwards , an airmass has to move *with sufficent acceleration to provide that up force. Bernoulii: the mass of air flowing through a channel times its speed gives the same product even if the channel then narrows to a waist: the air mass has to flow faster, but its pressure drops.. In this context: air flowing in an airstream over a wing sees it bulging (or waisting) and so that it needs to speed up, and pressure drops over the upper wing. Arguments of this type can be used as evidence that 2/3 of the wing lift is produced at the upper surface, and 1/3 at the lower wing surface. The larger truth: air pressure drops over the upper surface of a wing, and increases over the lower surface of a wing, and the resultant downflow balances the lift on the wing. Brian W theories anyone here really believe there is no change in air density as if flows at speeds of a hundred miles an hour past an airfoil? The equation works well for water flow in pipes and around boat hulls. It does not do such a good job of predicting pressures along an airfoil. Stick with Newtonian Physics and the gas laws. The ideal gas law still applies. Compressing airflow does indeed complicate Bernoulli as do the density changes involved but Bernoulli still holds up. Both theories remain correct even with compressible flow. But you are correct in that the Newton explanation is FAR easier of the two for people to deal with and understand. The only caveat I stress to instructors when getting into the lift issue is that they NEVER explain lift using ONLY one theory without mention of the other, as student pilots, once exposed to the lift question will invariably find through a credible source that BOTH Newton and Bernoulli are correct and that each can explain exactly the same thing to the 100% point. Lift can be explained to death. The deeper one goes into the explanation the more complicated it can get. Denigrating Bernoulli due to changing density and airflow speeds causing compression factors is NOT the way to present lift. Bernoulli stands. It's the math that gets harder when you compress the flow that's all. All this can be avoided by simply explaining to students that lift results when an airflow is TURNED, and BOTH Newton and Bernoulli can be shown to cause the airflow to turn as lift is being produced. Circulation, density, vortices..........all part of it, but it's the turning of that airflow that produces lift force and BOTH Bernoulli and Newton are working equally to produce that force, only doing it differently. Dudley Henriques AMEN! |
#37
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Lift - Newton/Bernoulli ratio...
On May 24, 3:26*pm, "Private" wrote:
"Dudley Henriques" wrote in message ... snip Absolutely..........without question! *The EXACT same explanation of lift creation is in play on an inverted wing as on the upright wing. Applies to barn doors as well. Newton= 100% *Bernoulli= 100%. Dudley Henriques Greetings Dudley, Glad to see that you have not abandoned hope for this place. Hope you are well. Best Wishes and Happy Landings. Thank you for the kind thought. Just passing through. DH |
#38
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Lift - Newton/Bernoulli ratio...
"Dudley Henriques" wrote in message ... snip Absolutely..........without question! The EXACT same explanation of lift creation is in play on an inverted wing as on the upright wing. Applies to barn doors as well. Newton= 100% Bernoulli= 100%. Dudley Henriques Greetings Dudley, Glad to see that you have not abandoned hope for this place. Hope you are well. Best Wishes and Happy Landings. |
#39
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Lift - Newton/Bernoulli ratio...
"Dave Doe" wrote in message ... In article , er, Private snip Not interested in trolling. If you think I am, please do not reply, or reply and say so, Which is exactly what I did. and I will do as such. -- Duncan. Recent experience has made all of us here somewhat cautious regarding the motivation of others. |
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