what the heck is lift?

"T o d d P a t t i s t" wrote in message
...
Pete, in your reply above, you did the same thing Roger did,
(and what I often do too,) you equated the vertical
component of aerodynamic force to "lift."

I made the assumption that when I wrote "See Todd's post" people would. You
clarified that quite well there, and I didn't see any reason to try to use a
finer brush than what started the thread.

The real issue here is whether lift changes according to airspeed. The
generic idea of lift (as in, the force that keeps airplanes aloft) versus
the specific physics definition of lift is inconsequential in that context,
and not one I feel is worth nitpicking over.

If you'll note, I also wrote "He's quite close". Had his definition of lift
been correct, he would have been exactly correct. Again, referencing your
post explains the minute detail where he was incorrect, and I didn't feel a
need to delve more deeply.

Frankly, I think this might be one of the reasons so many pilots don't
understand lift. As soon as the discussion turns technical, many people
want to make sure every last detail is just perfectly right. But in
reality, one can gain a very useful and practical understanding of lift
without ever knowing that lift is perpendicular to relative wind. Jumping
right into the minutiae of relative wind, vertical components, etc. just
makes some people's eyes glaze over, and they don't learn anything at all,
not even that lift is relatively constant over all unaccelerated flight,
regardless of airspeed.

Pete

Peter,
Todd wrote:
Pete, in your reply above, you did the same thing Roger did,
(and what I often do too,) you equated the vertical
component of aerodynamic force to "lift."
[zap]
The real issue here is whether lift changes according to airspeed. The
generic idea of lift (as in, the force that keeps airplanes aloft) versus
the specific physics definition of lift is inconsequential in that
context,
and not one I feel is worth nitpicking over.

It is *exactly* worth discussing and it is not nitpicking. Lift as DEFINED
is completely different to the force pointing upwards and there are many
examples where they all completely different; some example: spins, steep
turns, a plane climbing vertically, a flat spin, the F-18 slow pass...

OK, quick question: how much 'lift' (your definition) is an aircraft
producing in a 45 degree bank? Equal to the weight? If so, why does my
stall speed increase? Nitpicking? Well this nitpicking kills a lot of
pilots including very experienced ones.

How would you explain to a pilot that even though lift equals weight in a
steep turn (your definition), the stall speed increases?

Hilton

"Hilton" wrote in message
k.net...
It is *exactly* worth discussing and it is not nitpicking.

Not in this context. Still, you have demonstrated you are happy to continue
to do so, so please...knock yourself out.