Why is flawed aerodymics taught in flight schools?

[michal 44]

>>Bernoulli only accounts for a max 2%. Unfortunately it is a lot of crap to put in bluntly.>The equal transit theory is simply wrong, but it is taught>as gospel in many schools.at least this is something we can agree on. :-)Michael J.http://www.precisionmanuals.com/images/for...argo_hauler.gifhttp://sales.hifisim.com/pub-download/asv6-banner-beta.jpg>

[Guest]

Swept wings have nothing to do with lift theory per se, and everything with the specifics of moving an object through a compressible medium at speeds around and above the speed of sound (or the compressibillity barrier).Subsonic lift was well understood in the 1930s, good enough that they could create highly optimised wings for WW2 fighter and bomber aircraft which could operate close to the sound barrier.It was indeed not until the late 1940s that the effects of compressibillity on that wing were understood well enough to understand that a swept wing has better characteristics for the transsonic regime.Given your level of ignorance and your eagerness to believe junkscience and conspiracy theories (where the idea that flight schools, universities, and every other educational institution deliberately teach incorrect physics stems from) you wouldn't understand anything related to the Big Bang theory, let alone believe it if it were attempted to be explained to you.

[Guest DreamFleet]

Yeah, I think about "lift" and "Bernoulli" every time I am rotating for takeoff. Not!I remember the flight instructor who taught our PPL ground school, back in the mid-1970s, Mike Dybus. He was a good pilot, and I learned much from him along with other instructors I had trained with.I'll never forget one thing Mike said at one of the ground school lessons. "You can make a brick fly if you give it enough power".Now, just find a way to control the brick, and...He made a lot of sense.I too wonder why this subject comes up in FS forums. Never read about it in the real aviation forums I frequent. Then again, we often have far greater concerns to discuss in those forums.I guess it is just something to talk about, when one cannot be lamenting their latest Lycoming crank shaft recall, some other AD on their aircraft, or some problem that might cost major $$ to deal with.Or, next time you are a passenger in a car, roll down the window, and stick your right hand straight in the slip stream. Make sure your hand is flat, and perhaps curve it at the top.Now, rotate your hand up or down, so that your thumb (the leading edge) is either up or down, and watch what happens.Not very scientific, perhaps "flawed", but you can "fly" your hand up and down in this manner provided the car is going fast enough. Maybe they taught me wrong in flight school, 30+ years ago, then again hopefully the designers of the wing on my Piper got it right, and that's all I care about.It sort of works just like my hand outside the car window, only much better. ;-)Regards,http://www.dreamfleet2000.com/gfx/images/F...R_FORUM_LOU.jpg

[Guest Moonraker]

>>The equal transit theory is simply wrong, but it is taught>>as gospel in many schools.>>at least this is something we can agree on. :-)>You said you work for NASA? And you agree that the "equal transit theory" is wrong? Then how can you explain this:"Since air passing over the top andbottom must reach the rear of the wing at the sametime, the air passing over the top must not onlytravel faster, but also changes direction and isdeflected downward."...taken from this Nasa.pdf:http://www.dfrc.nasa.gov/Education/OnlineE...df/studlift.pdf(Section 3: "Developing lift")Having read so many different explanations of why airplanes fly and seeing how one author claims that the explanation of another author is simply completely wrong I don

[Guest Moonraker]

A few other links to Nasa-websites:http://www.lerc.nasa.gov/WWW/K-12/airplane/wrong1.htmlhttp://www.lerc.nasa.gov/WWW/K-12/airplane/wrong2.htmlhttp://www.lerc.nasa.gov/WWW/K-12/airplane/wrong3.htmlHere the "Equal Transit Time" theory is called "wrong"!Lift:http://www.lerc.nasa.gov/WWW/K-12/airplane/lift1.htmlhttp://www.grc.nasa.gov/WWW/K-12/airplane/lift2.html

[LAdamson 240]

>Given your level of ignorance and your eagerness to believe>junkscience and conspiracy theories (where the idea that>flight schools, universities, and every other educational>institution deliberately teach incorrect physics stems from)>you wouldn't understand anything related to the Big Bang>theory, let alone believe it if it were attempted to be>explained to you.Please explain again........... I don't understand... :-roll L.Adamson

[Guest Adverse Yawn]

>>P.S.: Wolfgang Langewische already used the Newton theory in 1944 in >>his book "Stick and rudder" !Yes, but if you read S&R fully you will have noted that he was not dismissing Bernoulli, but merely using N3 as a way of illustrating and clarifying how to control aeroplanes properly. The complex interplay between N3 and Bernoulli and the spawning of complex sub-effects as a result of that interplay is the last thing you should be trying to consider when flying a plane!I think that debunking Bernoulli is missing the point entirely. For arguments sake, even if Bernoulli only contributed 2% to the lift process (which is not true, because the spin-off effects if nothing else) then you need to consider how that lesser share in the effect made the practical use of aeroplanes from STOL to Airliners a practical and achievable possibility. If Bernoulli (or anybody since) has not discovered it, it probably would not have been possible to design wings fit for a purpose: no 747s and no Maules.

[Guest Adverse Yawn]

>>Even if the wing is symetrical (airfoil same, top & bottom), the wing >>still needs be be flown with a positive angle of attack to the incoming >>airflow. With a positive angle of attack, the air will still flow a >>greater distance over the top of the wing.I sort of agree. However, it needs to be noted that an asymetrical aerofoil can operata at a much lower angle of attack with all other things being equal. There is a reason why STOL aircraft have thick wings. Consider too extremely thin supersonic and delta wings, very little Bernoulli going on there, then again they produce very little lift but induce the coanda balanking effect at very high angles of attack where an ordinary wing would have stalled. Horses for courses.I don't think the water ski analogy works. There is no equivelent of downwash, washout, Bernoulli, coanda, ground-effect, etc, etc. Aeroplane's wings need to induce the pressure differential, in water skiing it is there by virtue of the massive density differential.

[Guest]

>>Please explain again........... I don't understand... :-roll >>L.Adamsonwhich proves my point :-lol

[Guest Moonraker]

>I think that debunking Bernoulli is missing the point>entirely. For arguments sake, even if Bernoulli only>contributed 2% to the lift process (which is not true, because>the spin-off effects if nothing else) then you need to>consider how that lesser share in the effect made the>practical use of aeroplanes from STOL to Airliners a practical>and achievable possibility. I certainly have read on an aviation-site that the Bernoulli-effect is MUCH too low to lift an airplane (probably somewhere around that 2% that have been mentioned here a few times) - I think there was even an example at what speed such an "theoretical" airplane (using only the Bernoulli - effect) would take off. If I remember correctly, a small plane would then have a take-off speed of several hundered knots...You may be right however that the Bernoulli-effect and Newton "interact" some way or other (plus some other effects like circulation) - but what do I know: I am no expert on that and can only try to "filter" the available information...

[michal 44]

>I certainly have read on an aviation-site that the>Bernoulli-effect is MUCH You really have no clue what was stated above about Bernoulii and how it applies (or not) to flying? And, by the way, please point me to this "aviation-site" that talks about this 2%. Yes, I want to see it and read it with my own eyes.Michael J.http://www.precisionmanuals.com/images/for...argo_hauler.gifhttp://sales.hifisim.com/pub-download/asv6-banner-beta.jpg

[Guest Moonraker]

>You really have no clue what was stated above about Bernoulii>and how it applies (or not) to flying? And, by the way, please>point me to this "aviation-site" that talks about this 2%.>Yes, I want to see it and read it with my own eyes.As you seem the only one here who knows EXACTELY how and why an airplane flies, I am, of course, deeply interested in fulfilling all your wishes, alas, it was serveral month ago that I read what I mentioned before on an aviation-site. Although I even saved this page and certainly have stored it somewhere, I cannot find it now and it would be a little exaggerated to start a big search just to please you... HOWEVER I started a little search with Google instead and found another site which claims the same things (unfortunately in German) but I will provide you with this link:http://www.rengels.de/misc/auftrieb.de.htmlThe important part is:"Eine Cessna 172, ein beliebtes viersitziges Flugzeug hat ein maximales Abfluggewicht von 1045 kg (also

[Guest Moonraker]

O.K. I just found out that the example with the Cessna 172 stems from the Dept. of Aeronautics and Astronautics University of Washington!I guess this SHOULD be a credible site! :-) You ARE a lucky guy - now you can read the English version, too!http://www.aa.washington.edu/faculty/eberhardt/lift.htm-->"One might ask if the numbers calculated by the Popular Description really work. Let us look at an example. Take the case of a Cessna 172, which is popular, high-winged, four-seat airplane. The wings must lift 2300 lb (1045 kg) at its maximum flying weight. The path length for the air over the top of the wing is only about 1.5% greater than under the wing. Using the Popular Description of lift, the wing would develop only about 2% of the needed lift at 65 mph (104 km/h), which is "slow flight" for this airplane. In fact, the calculations say that the minimum speed for this wing to develop sufficient lift is over 400 mph (640 km/h). If one works the problem the other way and asks what the difference in path length would have to be for the Popular Description to account for lift in slow flight, the answer would be 50%. The thickness of the wing would be almost the same as the chord length."

[mgh 89]

That quote is nothing to do with Bernoulli's theorem. It is based on a valid argument pointing out that the "equal time" theory is wrong.All the lift on a wing is generated according to Bernoulli's theorem, which is the application of the universal law of conservation of energy to fluid dynamics. If the air speed round the surface of the wing is measured it can be converted to pressure by applying Bernoulli's theorem to enable the lift force to be calculated.

[Guest Moonraker]

>That quote is nothing to do with Bernoulli's theorem. It is>based on a valid argument pointing out that the "equal time">theory is wrong.>>All the lift on a wing is generated according to Bernoulli's>theorem, which is the application of the universal law of>conservation of energy to fluid dynamics. If the air speed>round the surface of the wing is measured it can be converted>to pressure by applying Bernoulli's theorem to enable the>lift force to be calculated.May I cite David Anderson/Scott Eberhardt:"So, why has the popular explanation prevailed for so long? One answer is that the Bernoulli principle is easy to understand. There is nothing wrong with the Bernoulli principle, or with the statement that the air goes faster over the top of the wing. But, as the above discussion suggests, our understanding is not complete with this explanation. The problem is that we are missing a vital piece when we apply Bernoulli