I've researched this topic and as far as I can tell any plane can fly upside down if it's already in this position. It just needs to be angled enough so that its wings are angled upwards. I believe Boeing 777 can do this although I can't find any video proof.

But my real question is whether Boeing 777 can do aileron roll. From my understanding plane needs to pitch upwards a bit to gain altitude and then start to roll sideways. While doing this it will loose all lift and starts falling downwards until it is upside down and gains lift again. What are the requirements for this? What is the minimum speed it needs to achieve before attempting the roll? Is Boeing 777 structurally sound to survive the attempt? I imagine it was not designed for this but is it possible?

And a bonus question: can you link me a video of any bigger sized plane doing that?

  • $\begingroup$ As long as it remains a 1-G maneuver, it shouldn't be a problem. $\endgroup$ – Ron Beyer May 3 '17 at 20:28
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    $\begingroup$ A loop has different structural and loading issues than a barrel roll and an aileron roll. This question is a bit more specific than "aerobatics". The question also addresses inverted flight, which is more specific than "aerobatics." $\endgroup$ – mongo May 8 '17 at 14:16

In fact this has been done before. A well documented case is of "Tex" Johnston rolling a 707. In general airliners cannot do sustained inverted flight as they lack a fuel system (and lubrication system) for sustained inverted flight.

A barrel roll is readily executable. Youtube has a video of Tex Johnston doing a barrel roll.

Edit: I gave a quick answer and felt guilty about it. There is more to the story. The OP talks about aileron rolls. An aileron roll is a maneuver where the plane does not substantially change altitude. The G forces will be negative at some point, and it is more "violent" than a barrel roll. A barrel roll is a maneuver where the plane is rolled about the longitudinal and lateral axis, if you will, a loop and a roll in one. Properly executed the barrel roll is a positive G maneuver.

Years ago, when I was young and some old geezer was teaching me aerobatics, he would climb into the plane with a full cup of coffee. My job was to get to the practice area, and execute some maneuvers, including barrel rolls in each direction, without spilling his coffee.

  • $\begingroup$ Technically, that was a 367-80, which is closer to the KC-135 than to the 707 (the KC-135 is basically a straight production run of tanker-equipped 367-80s, while the 707 is fairly extensively modified from the 367-80, with, among other differences, a significantly wider fuselage); they're still close siblings, though. $\endgroup$ – Sean Jul 27 '19 at 22:10

Structurally, only just. Design regulations stipulate that the aircraft must be able to withstand accelerations between -1 and +2.5 g. So structurally it could fly upside down but It would be at borderline structural failure. A barrel roll spends very little time at inverted and does not impose -1 g, and passenger planes can be seen doing this manoeuvre at airshows, a beautiful sight.

  • $\begingroup$ -1g is a very small margin: it means that you could in theory have sustained inverted flight, but any time you push the stick you put the aircraft outside of that margin. $\endgroup$ – Sanchises May 6 '17 at 9:38
  • $\begingroup$ Yes indeed, they need to be very careful when upside down :) $\endgroup$ – Koyovis May 6 '17 at 11:43
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    $\begingroup$ I think there is a discrepancy between "very careful" and "no problem". $\endgroup$ – Sanchises May 6 '17 at 11:54
  • $\begingroup$ You're absolutely right, I've amended the answer. $\endgroup$ – Koyovis May 8 '17 at 4:31

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