In article ,
Dudley Henriques wrote:

On Friday, October 3, 2014 5:28:05 PM UTC-4, Robert Moore wrote:
Orval Fairbairn wrote

Any airplane that can take 3G can be aileron rolled successfully. It

would be like watching an elephant dance.



Why 3Gs? I don't recall any specific elevator input when doing

aileron rolls back in my Navy aerobatic training nor more

recently while flying a YAK-52. You aren't one of those people

who confuse aileron rolls with barrel rolls are you?



Bob Moore

I'm fairly sure Orval means that the airplane should be capable of at least
3g's coming off the backside of the roll, especially for a non-aerobatic
airplane. In an aileron roll in these airplanes you will be above 1g
temporarily as you pull the nose up to a set point to initiate the roll. Once
the roll begins you can of course unload the wing or go over the top at 1g as
desired. But the back side recovery will be a rolling pullout with
asymmetrical g loading on the wings. It's here you have to be careful in non
aerobatic aircraft. The ability to handle at least 3g's would be a reasonable
number.
Dudley Henriques

Another factor, not usually talked about is the lateral centrifugal
accelerations imposed on the engine pods -- both lateral from the
rolling and the coupled inertial forces between the rotating masses and
the airframe attitude changes.

An old co-worker described an autopilot test in the Convair 880:

He was applying a preplanned set of gains to the autopilot and reading
the aircraft responses when another told him to look outside at the
engines. He said that one of the engines was moving in a figure-eight
motion -- they immediately suspended the tests.

When you have such large, flexible structures flying in unusual motions,
you may see some unusual (and not always pleasant) sights.