wrote:

first 707 - barrel roll

To be picky, the 367-80 did an aileron (aka ballistic)
roll, not a barrel roll.

A barrel roll is actually best thought of as a spiralled
loop, which by necessity is going to pull 3 to 4 G's.

An aileron roll is much more gentle: get some speed,
pitch up, neutralize in pitch, then full aileron, and
wait 'til it's blue at the top again. The reason you
pitch up is to avoid an excessive nose-down pitch angle
at the end, which results in loss of altitude and excessive
airspeed.

The slower the roll rate, the greater the initial pitch
angle required, and the greater the initial airspeed required.

If you reset the G-meter, you should see +2 and +0.5 as the
telltale values after the aileron roll. +2 during the pullup,
and +0.5 while inverted.

Then there is the completely misnamed slow roll, in
which the aircraft rotates around it's longitudinal
axis, at any rate of roll - faster is easier. The
slow roll can be done in the horizontal or vertical,
or on any angle inbetween.

And then we have the point (aka hesitation) roll,
which has pauses during the rotation of the slow roll.

Then there is the snap roll, which is a violent, high-G,
stalled, yawing maneuver, which is a cousin of the spin.
A snap roll can be performed with either positive
or negative G. High torsional loads are imposed on
the airframe. Gyroscopic precession of the propeller
can be very hard on the crankshaft, too.

Then there is dutch roll, which has to do with
the roll/yaw coupling of swept-wing aircraft - this
oscillation was especially noticeable in aircraft
with undersized vertical fins such as the 707. IIRC
the initial "small-tail" variants of the F-100 and
MiG-21 and many others were later upgraded with
larger vertical fins.

There's a funny story behind why the F-86 didn't
suffer from dutch roll, but that's getting way
off-topic.

--
ATP www.pittspecials.com