"(Zapletal Writes->) 

 Steelpillow, you wrote: 

 1.  ""I do find the airship analogy dangerous, perhaps spurious. The situations are utterly different...""  

 Just before making that analogy I wrote: 

  ""5. TWO CASES TO THINK ABOUT. - ... please don't say ""Oh, but that's different..."" ...""  

 The first ""airship"" example was intended to make clear that a Lift force can be created in a fluid by pressure forces alone, so -dP/dt is NOT absolutely essential. The second ""wave"" example hinted at how dynamic effects can create such Lifting pressure zones. 

 ~o0o~ 

 2.  ""Only part of the overall flow pattern supports the aerofoil ... in that part that actually supports the wing, the air is being deflected downwards. [etc...]""  

 That whole paragraph is wrong, or at the least, very misleading. All parts of the flow pattern depend on all other parts of the flow pattern. That is why it is called ""Continuum Mechanics"". 

 Any smallish volume of fluid near the aerofoil (ie. any fluid that might be said to ""actually support the wing""), necessarily has very small mass. There is simply NO WAY that this small mass can cause ALL of the Lift via its -dP/dt. 

 Instead, this small volume of fluid is responsible for a VERY SMALL part of the Lift, via its downward dP/dt. The rest of the Lift comes from the PRESSURE FIELD surrounding this small volume. That pressure field (established when the aerofoil first started to move, or accelerated) is also related to the momentum changes of all the other parts of the fluid, more than half of which are now UPWARD dP/dts.  
 ~o0o~ 

 3.  ""Thus, in practice, the application of dp/dt is quite complex ... So the true debate here should [be, how do we give] a simple introduction to the Newtonian model of dynamic lift ... introducing the basic principle ... to the relevant localised airflow...""  

 What you are suggesting is that this article should teach a FALLACIOUS model of Lift, for purely IDEALOGICAL reasons. (This shouting is just to make this point clear, so I don't have to repeat it.) 

 Specifically, your qualitative ""Newtonian Model"" is incapable of giving any quantitative results. To get any results at all, you must first know the Lift, then ARBITRARILY assume an amount of mass to do the Lifting (ie. your ""relevant localised airflow""), after which you get an ""average"" acceleration value, but NO IDEA of what the actual flow field looks like. 

 This is an utterly useless approach to understanding FDL (ie. it is of zero help in designing aerofoils), that is taken simply to support an idealogical viewpoint (ie. that ""Lift MUST be due to Downwash...""), with that viewpoint being WRONG anyway (ie. as many others here now agree, there is NO NET change of vertical momentum). 

 As I wrote earlier, 

 ' ""In short, the editors of good encyclopedias filter out the nonsense. If this does NOT happen, then very soon we will have to believe that the world is flat, voodoo is real, and the star signs predict our future."" ' 

 To which we might have to add, ""... and, because Newton said so, all FD-Lift is due to Downwash"". And maybe after that ETT can make a comeback. 

 ~o0o~ 

 4.  ""Besides seeking refutations of Clancy's position, I emphasised the importance of relevant citations. I had hoped for verifiable quotations clearly relevant to Newtonian flow deflection and explicitly countering Clancy's position, yet the silence on this point is becoming deafening. No relevant citations, no progress.""  

 Again, your deafness seems decidedly idealogical in nature. 

 As already quoted and cited many times, the major part of Lanchester's book is directed at refuting ""Newtonian flow deflection"". All of the ""Circulation/Vortex Theory of Lift"", hugely successful for 100+ years, and which has countless citations from umpteen reliable sources, refutes it. 

 If anyone is seriously interested in this Article, then they should study this body of knowledge more deeply before trying to impose a false idealogy upon the next generation. 

 I will be away for the next week, so not able to respond to any questions for a while. 

 (End Zapletal)    

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