Thread: Discussion NASA says lift from air shoved down - can we trust NASA? View Single Post
Nov 14, 2011, 07:23 AM
Launch the drones ...
Ashtabula, OH USA
Joined May 1999
3,722 Posts
Quote:
 Originally Posted by stardustertoo Hi Tim, I will be nice this time...I promise Please, for the sake of the discussion, rather than completely shutting everything off, open your mind a bit to the whole picture. Never once did we disagree with you about it being shoved down, we all agreed that does take place, but there is a lot more to it than that. For Example, since you like NASA links, here is one from the same guys as your link that say downwash reduces lift, rather than causes it. http://www.grc.nasa.gov/WWW/k-12/airplane/downwash.html Cut-n-paste from this link "The wing tip vortices produce a downwash of air behind the wing which is very strong near the wing tips and decreases toward the wing root. The local angle of attack of the wing is increased by the flow induced by the downwash, giving an additional, downstream-facing, component to the aerodynamic force acting over the entire wing. The downstream component of the force is called induced drag because it faces downstream and has been "induced" by the action of the tip vortices. The lift near the wing tips is defined to be perpendicular to the local flow. The local flow is at a greater angle of attack than the free stream flow because of the induced flow. Resolving the tip lift back to the free stream reference produces a reduction in the lift coefficient of the entire wing". This one is neat, also from your same source. This one is called The Lift Equation, and what do you know, this "official" NASA lift equation has not just the velocity of the air, but it also takes into account the dynamic pressure, and it says that that portion of the equation is taken from Bernoulli's equation...wow!! http://www.grc.nasa.gov/WWW/k-12/airplane/lifteq.html Cut-n-paste from that link: In the equation given above, the density is designated by the letter "r." We do not use "d" for density, since "d" is often used to specify distance. In many textbooks on aerodynamics, the density is given by the Greek symbol "rho" (Greek for "r"). The combination of terms "density times the square of the velocity divided by two" is called the dynamic pressure and appears in Bernoulli's pressure equation. And here is yet another one from your very same source, which explains hw both the pressure difference/Bernoulli theory and turning flow/Newton theory are BOTH correct, if applied correctly. the quote: "So both "Bernoulli" and "Newton" are correct. Integrating the effects of either the pressure or the velocity determines the aerodynamic force on an object. We can use equations developed by each of them to determine the magnitude and direction of the aerodynamic force. " The link http://www.grc.nasa.gov/WWW/k-12/airplane/bernnew.html And here is another one from them same fella's that explains in detail Bernoullli's principle, his equation, and how it relates to lift. It also states how you can use his equation to calculate the TOTAL AERODYNAMIC FORCE on the airfoil....here is that direct cut and paste quote.... "Along a low speed airfoil, the flow is incompressible and the density remains a constant. Bernoulli's equation then reduces to a simple relation between velocity and static pressure. The surface of the airfoil is a streamline. Since the velocity varies along the streamline, Bernoulli's equation can be used to compute the change in pressure. The static pressure integrated along the entire surface of the airfoil gives the total aerodynamic force on the foil. This force can be broken down into the lift and drag of the airfoil." And the link... http://www.grc.nasa.gov/WWW/k-12/airplane/bern.html So my friend, it seems as there is a heck of a lot more going on than simply, air being shoved down, as your own guys pointed out in that really cool website they have. So, does shoving air down produce lift...yup. Does the pressure difference produce lift...yup. I know we went through this before (at great length) and I know you won't want to listen, but come on man, your experiments do not prove anything to do with lift. Myself, Bruce Matthews, and a couple others made that pretty clear. Don't even start with them again.
Regarding your accusation that I don't listen - I find your posts vacuous, with lots of words used as a substitute for logic. So, please stop telling everyone I don't listen, because I do. I love logical discussion - but broadsides of useless verbiage aren't useful to me.