PPRuNe Forums - View Single Post - Which one to believe; which version of lift is taught for the ATPL theory exams?
Old 13th Jan 2010, 18:31
  #19 (permalink)  
ft
 
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A very select group, indeed! Those I trust to know what they're talking about. I strongly recommend everyone to be no less selective. There is no shortage of bad references out there, and you are certain to find them if you e g google for references to support your opinion without being very critical and making sure that you fully grasp what they are saying.

Always apply a basic sanity check. One example would be to check if the author has received a Nobel prize if he or she is claiming to have found a way to circumvent the basic laws of physics, such as Newton's laws.

In actual practise, this means that if someone claims to have a force without an equal and opposite reaction, or to be able to apply a force to a mass without accelerating it, you should check for a Nobel prize in physics. If their work is more than a year old and there's no Nobel prize in their CV, their work likely did not meet the scientific standards.

Also be very vary of any reference selling by being devoid (or almost devoid) of mathematical formulae, such as your first reference. Many very good books are without formulae, but to have it as a selling point is a warning sign of simplifications. While the book in question looks to be well written and interesting, to the point where I'm contemplating getting hold of it and reading it (thank you for bringing it up), the quote chosen is peculiar.

As the air forms a vortex after being pushed down by the wing, there's no momentum change? No momentum imparted to the air since it rotates? Now, that's an interesting take on certain other things, such as propellers and flywheels.

Also check out the way smoke rings move the next time you are attending a party. A smoke ring is a vortex. There's a similarity to be found - and I'm fairly certain it's even in the PPL syllabus.

As for your second quote, it is first off obviously out of context as it is refers to a previous statement. I'd like to read it in context. Secondly, no, as he rightly points out momentum change does not succeed in rubbishing circulation theory as they go very well together. For the rest, I again refer back to Newton, sanity check and out of context quoting.

Your third quote is from an author I respect immensely. Thus it is with great relief, if little surprise, that I see that he supports my case against the FAA. I must admit to being bewildered about your choice to include the quote though, as your reference to the honourable John D does not contradict anything I have said. BTW, read his books if given a chance.
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