On May 22, 7:04*pm, Mxsmanic wrote:
Dave Doe writes:
Does anyone have any figures and references for about what ratio lift is
produced by Newton's Laws and Bernoulli's Laws?

All lift is produced by Newton's third law of motion. Air is forced downwards
by the wings, and this produces an equal and opposite force that attempts to
raise the wings, and that is lift. How the air is forced downwards is
irrelevant, as long as it happens. In practice, principles discovered by
Bernoulli and others play a role in diverting the air flow when this is
accomplished by an airfoil.

Actually, if I'm reading you right, I would rephrase this just a bit,
as it feeds into the problems we as instructors have in "re-
explaining" lift to students.
STRESSING either Newton or Bernoulli in the lift explanation causes
more than a modicum of confusion UNLESS it's done by including BOTH
theories in the explanation. You've done that actually. I would just
enhance things a bit more :-)
Read what Orval says above. He is absolutely correct. BOTH Newton and
Bernoulli are COMPLETE explanations for lift, which is interesting in
another respect, as neither man had lift in mind with their work.
The simple truth of it is that each explanation is totally correct and
is interchangeable with the other. Each explains the same thing
without relying on the other and BOTH are occurring simultaneously.
It's a common misconception that Bernoulli and Newton EACH contribute
INDIVIDUALLY to form a TOTAL of the lift produced. This explanation is
incorrect and should be discouraged.
When I dealt with the lift issue with instructors in seminar, my
personal approach was to favor the Newtonian explanation as in my
opinion student pilots can grasp Newton a lot easier than Bernoulli,
but I've ALWAYS made it habit NEVER to leave Bernoulli out in the
cold.
The correct way to deal with the lift issue is to explain to those
asking that BOTH explanations are complete by themselves, and Newton
might be the easier of the two to explain.
Dudley Henriques