Anyone who doesn't know the difference between barrel
roll and an aileron (aka ballistic) roll shouldn't fly aerobatics.
A barrel roll is really a spiralled loop and as such is going
to involve some G (eg +4G), like any other vertical aerobatic
maneuver.
An aileron (aka ballistic) roll is a far gentler aerobatic
maneuver, involving max +2G in the pitch up in the
entry, and +2G in the pull at the exit. While inverted
the G is light and slightly positive. Properly flown,
the maximum G experienced is +2G and the minimum
is around +0.5G. This is much less than would be
experienced in a barrel roll.
Tex Johnston did an AILERON roll in the 367-80 at
the Seattle Hydroplane races, from 1500 AGL. Twice.
He surely did not barrel roll it.
Even though people here might get upset about it,
it is a sad state of affairs that:
1) pilots don't know the difference between an
aileron roll and a barrel roll
2) so-called professional pilots do not have the
skill to perform even a simple roll.
I can teach anyone to aileron roll any aircraft in
2 minutes. It's that easy and simple. How people
screw it up and manage to kill themselves is an
ongoing mystery to me. Sort of like killing yourself
with a can opener. I suppose you could, but I
don't know why.
Properly flown, an aileron roll does NOT impose
any unusual stresses on an aircraft. When you
are upside down, the G is still slightly positive -
the aircraft doesn't know it's upside down!
Here is an aileron roll I flew recently in a jet,
which I entered at the surface. It doesn't
get any easier than this:
http://www.pittspecials.com/images/roll.jpg
Didn't Bobby Younkin fly a Lear 23 on the
airshow circuit a couple years back? Gosh,
he could sure fly that Beech 18 of his.