Rolling a 172 - or not

This started when you stated that aileron rolls don't cause positive G's
all the way around,

IIRC, I responded to a posting that said it was a "one G" maneuver,
which is what I disagreed with. Perhaps my memory is faulty on that
score.

Erm, well, we can stop right there, because that's what the problem
is... here's your article and my initial response (my stuff with the
single ""):

In article ,
vincent p. norris wrote:

Not if you maintain positive G all the way around (as in aileron
roll).

You don't have positive G all the way around in an aileron roll.

I believe that's essentially true.

As I said more recently,

But if an airplane is in inverted flight,
it takes at least 1.000001 positive Gs caused by acceleration to
overcome the negative G caused by gravity and produce a G sum that is
positive.

And I said that I have serious doubt there is enough "corkscrewing" in
the aileron rolls I've done, and seen others do, to produce more than
about 1 G. Maybe a bit less.

I would not suggest there are *noticeable* negative Gs, like a slow
roll; as I said, I don't hang on my seat belt. I think that halfway
through the roll, the airplane is *essentially* (i.e., for all
practical purposes) in a zero-G condition. I tried to say that
before, but perhaps I didn't say it well enough.

For that matter, when I "unload" the stick to begin the roll, I am
just about at zero Gs. I *attempt* to create a zero-G condition. I
believe that is the correct procedure. I'm sure I can't produce
exactly zero Gs every time, to several decimal places; no doubt I
sometimes produce a slight negative-G condition, sometimes a slight
positive-G condition.

Apparently you do not agree with that. I'm not suggesting you ought
to change the way you do aileron rolls, or think about them; I am
simply saying what I believe to be the case.

I've expressed my views several times, so I don't think there is much
to be gained by my repeating them again. We can just agree to
disagree.

Oh well. I think I kinda suspected this -- if you'd actually said it
wasn't a *1 G* maneuver, I'd have agreed wholeheartedly.

I imagine you would have. On that subject:

In a protracted discussion with a friend who is an aeronautical
engineer prof, specializing in aerodynamics, a year or so, in reaction
to an earlier thread on this newsgroup, we came to this conclusion:

"There is no such thing as a one-G maneuver."

An airplane flying straight and level, at constant speed, on a
smooth-air day, experiences one positive G.

ANY departure from that condition changes the G, either in amount, or
direction, or both.

Yet we often hear about "one G maneuvers." I think people use the
term to any maneuver that does not produce *palpable* G forces on
their bodies.

In that peculiar, inaccurate, sense, I suppose I would agree with the
statement that an aileron roll is a "one G maeuver."

vince norris