[pedrocr]

I read something similar in John Boyd's biography (highly recommended) about the barrel roll as well. I assume they mean it can be done while keeping the plane in a 0.9-1.1G window or something along those lines. In other words in can be done in a way that if you closed the blinds on all the windows and did it in a commercial flight full of passengers no one would complain or even be able to tell.

[TylerE]

That's not true. There will still be rotation that can be felt.

[cyberferret]

I had a beer with a B-1 Lancer pilot who was here on exercises many years ago. He said that on low level flight infiltration exercises, his normal method to go over ridge lines and small hills is to pull the aircraft gently up, roll it inverted and pull back while cresting the ridge, then roll upright once over.

He said he is experienced enough to maintain 1.0 to 1.5G throughout the manoeuvre, and the most of the time, the weapons guys in the back of the plane who are usually 'heads down' and don't have big windows to look out of, don't even realise they were inverted for 10 to 15 seconds.

He said he has a standing wager with them when they land, and if the back seaters can accurately tell him how many ridgelines they crested inverted correctly, he buys them a beer. He told me he hardly ever has to buy.

[Moru]

We humans are pretty funny. The sensitivity comes a lot from what the eyes see, the hands feel and what we expect to happen from what the experience tells us (stick movement and such). Only a small ammount of it comes from the inner ear balance sense.

Try standing on one leg. Then close your eyes. Or try walking in a very dark but not completely black room. And then close your eyes. Your balance sense might tell you very strange things and if you haven't trained for this, you might fall.

[falcolas]

Below a certain threshold, somewhere near 5 degrees a second, your inner ear can not sense the rotation. It's why you need instruments when flying without visual cues.

Oh, it can also tell you you're tumbling wildly when you are actually going completely straight. Really disorienting.