I was thinking about the difference between a jointer (powered) and a
plane. A jointer has the outfeed table level with the blade so that as
the work passes over the blade and onto the outfeed table, if the
operator uses good technique to keep the board flat on the outfeed
table, the board pretty much has to come out FLAT.

A hand plane on the other hand isn't built that way. It has a
projecting blade. So unless the sole of the plane is extraordinarily
long, how can you get a perfectly machined straight board? Just for
grins, I was using a tiny hand plane to plane the edge of a board and
found that no matter how hard I tried, the small plane "unflattened" the
straight edge I started with. The more passes, the worse it got. How
long of a plane do you need to get a perfectly flat result on say a 2'
board? a 6' board? Is it MOSTLY technique, or do you have to have a
reference straight edge and keep checking your work constantly as you
plane? OR do you just take a few light passes over an essentially flat
board to start with, and know that it is flat? In other words, when I
use the jointer, I KNOW it's flat. I don't have to check it. Can I do
the same thing with a plane, or do you have to stop, eyeball it with a
reference straight-edge, and then touch it up an little here, a little
there?

Lay it on me, WW gods!

dave