Originally Posted by dave1993
maybe its just me but im less impressed by aerodynamic theory than real world obesrvations.
Maybe this thread ought to just park until Dave shares those real-world observations he is always talking about-- don't know why he won't share those pressure readings from the top/ bottom of the wing of his park flyer that show how the high pressure on the bottom surface is the dominant effect contributing to the lift force on the airfoil? Not that that has anything to do with whether lift involves a downwash (which it does), but still, it seems to be one of his favorite topics, so why won't he share the evidence with us? Maybe-- it's because that would belong in the "modelling science" forum? Which this is not...
This is the "bash academic theory" / "extol the virtues of my favorite branch of RC flying and bash the rest" / "make generalized physic arguments about lift based on quirky things I think I'm seeing in slow flying aircraft" / "misrepresent my opponent's statements/ predictions" / "engage in illogical arguments" / "argue against the existence of logic" / "accuse everyone else of being a religious nut case" forum.
You mentioned playing with cooling fans in your last post.
We all know that a propeller makes a strong propwash behind, but not in front of, the propeller disk, in terms of the velocity of the flow at any given point. (I.e. the outflow is much more concentrated than the inflow.)
So, is this yet another manifestation of the idea that an airfoil has a stronger high-pressure area on the bottom and only a weaker low-pressure area on top? If the low pressure on top were stronger than the high pressure on the bottom, then the "sucking" propwash in front of the prop would be stronger than the "blowing" propwash behind the prop? Even if the prop is operating at a very high airspeed and is using an airfoil whose pressure distribution is well known to be the opposite (low-pressure on top of the airfoil is stronger than high-pressure on bottom)? That would pretty much be the logical extension of the positions you've taken over the last few days.
Real world this, real world that, we would be all ears if you would tell us something from the real world that pertained in any real way to what we've been talking about. Rather than saying "you'd get all this if you knew about thin films, so go google thin films".
This thread is long overdue for being put out to pasture...
On the other hand maybe it ought to remain as a special preserve for this kind of twisted discussion-- sort an exhibit, a museum, a zoo?