On 29 Oct 2018, at 1:03 pm, '.' eruttan@yahoo.com [harryproa] <harryproa@yahoogroups.com.au> wrote:

The engine mounts see no forces in a barrel roll they don't see in normal flight. A barrel roll is a 1 g maneuver. Which means, from the aircrafts point of view, the aircraft sees the floor as down for the whole maneuver. There are countless of not aerobatic type aircraft doing barrel rolls while people hold or pour some sort of fluid on youtube. It's a thing. Planes don't fall out of the sky performing them.

The aircraft was never inverted from its point of view. The mounts saw no compressive force. The never even saw 0 force. Everything in the aircraft was loaded toward the floor like normal.

Bob hoover drinking tea while inverted is a video you can look for.

I do not really want to argue this anymore. But if I am wrong, please let me know.