Time it takes air to travel over and under an airfoil

A little while ago I reread the Pilot's Handbook of Aeronautical Knowledge chapter on lift. It seemed to go out of its way to paint lift production as a mystery of faith that men cannot truly understand. It is far from it. My blanket statement:

Lift is the most well understood aspect of applied aerodynamics. It and its related quantities (induced drag) are the easiest to predict.

Drag, now that's a tricky devil.
 
cmill said:
Im kinda simple, and by far from an aerodynamics guru, but I understand correctly, if it were required for particles to re unite, how would a wing stall?
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Thats a good point, and it wouldnt it also mean that you would generate lift at 5 KTS?
 
gromm44 said:
Thats a good point, and it wouldnt it also mean that you would generate lift at 5 KTS?
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I am assuming your asking if you would generate lift at 5 knots, the answer is it depends on the aircraft. Most jet aircraft wings are symmetrical and set at 0 AoA, thus they will not generate lift until they begin to rotate. Almost any other aircraft will have some angle of incidence, in other words an inherent AOA and/or not be symmetrical. These aircraft will generate lift at any speed. As long as a wing has an AOA or is asymmetrical it should generate lift at any speed, just not enough to overcome weight until the AOA is increased to critical and the minimum (stall speed) is achieved.
 
tgrayson said:
I wonder what the DPE would say if you asked him why he was asking you questions outside the boundaries of the PTS? ;)
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At least one DPE I know would smile and say "I'll be right back with your Notice of Disapproval"

poser765 said:
excuse me...someone with authority...would you be so kind as to replace the "senior member" under my name on the left with <sky god of the universe>. Thank you.
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I don't know if the vBulletin software allows title changes for individuals (phpbb does, but that's not what's running)
 
Mike H said:
At least one DPE I know would smile and say "I'll be right back with your Notice of Disapproval"
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Then that DPE needs a smackdown. These guys don't have the lattitude to ask about whatever they wish, even more so when it results in a failure.
 
Holy crap my head exploded reading this thing.

How does Newton's 3rd create lift then? Crap I'm not smart enough for this stuff anymore.
 
tgrayson said:
Then that DPE needs a smackdown. These guys don't have the lattitude to ask about whatever they wish, even more so when it results in a failure.
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Want to know what he'd say to that?

2 words: prove it.

Your word against the DPE's word. Whose story do you think the FSDO might give more weight to? And besides, if the DPE has just failed you, you might just have a reason to "exaggerate", right? It's a case of being in the right not doing you much good.
 
"Prove it" was exactly what he did say to an applicant whose airplane he broke on a checkride (although the applicant did pass the ride)- the DPE refused to pay for the repair, however
 
Mike H said:
"Prove it" was exactly what he did say to an applicant whose airplane he broke on a checkride (although the applicant did pass the ride)- the DPE refused to pay for the repair, however
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Sounds like a stand up kinda guy...
 
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