Originally Posted by bfisk
Ithe level you are analyzing this at is far beyond what would be expected for a PPL or CPL candidate, at least in the US.
I've said this to one or two other respondents, but I'm not trying to teach complex theory... just the right theory. In here amongst friends we can get a bit technical!
Originally Posted by bfisk
...although we need to be conscious about not teaching something that's blatanty wrong - imho we are allowed to, and need to, make simplifications.
I'd agree with that. But there's a big difference between simplification and teaching something that's not right.
Originally Posted by bfisk
it's not written in stone anywhere that one answer has to be 100% correct, and the distractors 100% wrong. It is sufficient to have one answer better than, more complete than, or more appropriate than the distractors. This adds a certain level of discrimination to the test....
It's a good idea to blur the lines to test the candidate's thinking, but I'd disagree that the correct answer can be (say) 60% correct. What about 30% correct? What about 90% correct? Just where is this line drawn? What chance does a candidate have in picking the "most correct answer" if the candidate's thinking has been skewed by an incorrect model?
Originally Posted by bfisk
Answer C talks about "larger" and "lower" center of pressures... to my knowledge, the CP is the point at where the total aerodynamic force can be said to be accumulated.... lift is primarily created by a pressure differential between the upper and lower surface of the wing; correct? While none of the answers are a complete and correct explanation, answer B is the most correct. Mind you also, the question stem specifies "an aircraft wing", which is not a flat plate.
Yep, this has been pointed out before. On balance, I do now agree B is "more correct" than C. But this is a good example of why an incorrect model causes confusion, when neither are correct.
Originally Posted by bfisk
As far as professional development is concerned, this is excellent reading for a ATPL student, CFI or whoever is beyond the basics. Let's just keep in mind that most students will be entirely satisfied with just keeping the blue side up, and we must be take great care in not scaring them away by theoretisizing too much about something which is really beyond our, and their, control, anyway.
I think you misjudge the capacity of our students. Students will learn basically what we teach them.