Peter wrote:
What would cause the pitch-down?
One advantage of some aerobatic training, are the following lessons, if your inverted or nearly so, you will need forward stick pressure to KEEP the nose above the horizon. In a barrel roll where you keep positive G, it is essential that the nose is already sufficiently above the horizon ON ENTRY as it will constantly trend towards the axis of the roll, that direction will be towards the ground while your inverted. The other is from an inverted position pulling back to complete a loop requires far more altitude and may exceed many V speeds, than rolling level again.
What the pitch moments are during inverted flight is probably better discussed in a separate thread 
Yes, of course, if you start of a roll and take your time over it then you get a pitch-down, and it can easily be non-recoverable. I just thought that encountering a wingtip vortex produces such a high roll rate that there isn’t time to get much of a pitch-down.
Peter wrote:
What would cause the pitch-down?
The wake vortex should produce a roll, only.
As MattL said they are already pitch down on low power, I will add probably no height and slow/fast speed margins
I would assume if one fly the middle the green-white speed band (Vs, man(Vb,Va,Vfe)) without much power and some spare 2000ft agl height, good harnesses & visible horizon they may have more chances to get away from it, but surely not when you fly too slow or too fast at 500ft agl? aerobatic training experiences stops at 500agl everybody will tend to intentionally pull up the stick bellow that when they are caught by surprise…
Peter wrote:
Yes, of course, if you start of a roll and take your time over it then you get a pitch-down, and it can easily be non-recoverable. I just thought that encountering a wingtip vortex produces such a high roll rate that there isn’t time to get much of a pitch-down.
One data point would be the 152 that I did a lot aerobatic instructing in, if you use full aileron at about 130kt without any initial nose up entry, it would be a about 10 degrees below the horizon, if you paused for second, or pulled harder on the stick by the time we went all way around I would guess an attitude of 45 degrees. This would just be observing a student who had already been briefed on what do… (the oil system of the152 is not capable of the classic slow roll)
Perhaps a better summary would be nose attitudes 45 degrees from where they were supposed to be during the initial phase of aerobatic training would not be uncommon.
