Barrel roll And g's Quest.

Hello:

I'm not a pilot.

Saw a show on the first 707 on the WINGS TV channel regarding the barrel
roll
the test pilot did (unexpectedly) on the first test flight of the dash-

They said that he was able to maintain a constant 1g during the maneuver.

Here's where i'ma bit confused.

Seems to me that at the top of the roll, he would have had to be rolling at
a rate
sufficient to have centripital force equal to 2 g; such that when you
subtract the normal downward
1 g, there's a resultant 1 g left acting in the conventional direction
(tending to pull the engines away from the wings-the same
as if in a normal level flight)

If so. what happens to the 2g when the plane is at the 3 and 9 o'clock
positions?
The resultant there would be over 1g, wouldn't it ?

What am I misssing, or mis-interpreting ?

If someone could walk me thru the maneuver, and the resultant g's at the
various
positions, would be most appreciative.

Also, could exactly the same result(s) be obtained via an aileron roll ?

Thanks,
Bob