Loop the loop?

[JjP]

What is the largest passenger plane to be able to loop the loop?

[Ewood27]

I have to assume that this really is a genuine question. If you're thinking large passenger jets, forget it. Performing a loop requires pulling several g's to heave the aircraft up to and beyond the vertical and over the top before running out of airspeed, and several g's again on the way down to level out before exceeding the aircraft's maximum speed. Airliners simply are not built to take those strains. They are not necessary and would add a punitive amount of weight to build in the strength required. That in turn would mean fewer passengers could be carried and the aircraft would not be a commercial success.
It is possible that some of the smaller executive jets, such as maybe the Learjet, could take the strains involved, but again that is not what they were made for.

[Cetti]

Ewood has the experience and knowledge to give you the definitive answer - but there is a 'story' that the Concorde flew upside down whilst on a Test Flight, when of course there were no passengers present. I think that's the nearest you'll get to looping the loop.

[Ewood27]

Haven't heard that one, Cetti, but such stories do get bandied about. I should have mentioned, anyway, that what may be possible, though I'm sure not officially authorised, is for some aircraft to do a barrel roll. In that the nose is pulled up to (typically) about 30 degrees while rolling, reaching that angle as the wings reach 90 degrees, continuing to be inverted as the nose comes back down level, then continuing the roll to 30 degrees nose down with wings at 90 degrees again, and back up to straight and level. That's a kind of extruded loop and requires far lower g forces. I could believe that Concorde was barrel-rolled.

Negative g, though, as in flying level inverted, means the wings have to provide lift "downwards", which they're not designed for. Aerodynamically they can do it, but their strength is perhaps not up to it. It doesn't half make a mess of fuel and oil systems too, not to mention other equipment coming adrift. Aerobatic aircraft have to be built like brick chicken-houses!

[sddsddean]

When the Boeing 707 was being test flown (late 50's?), its test pilot performed a chandelle (a 1g manouveur similar to a barrel roll) whilst the cameraman filmed from the cockpit looking toward the horizon, so the view of the horizon was recorded going round as proof they had done it. Apparently the test pilot was asked by 'management' what he was playing at. He said it was a perfectly safe 1g manouveur and thought it might impress prospective buyers of the new jet. He was told that maybe it might, but don't do it again!!

[jillybean]

i think they should invent a passenger plane that could do barrel rolls etc, i mean that would just be classy!!!!! tell me when they invent a jumbo that can do it :o)

[Ewood27]

Jillybean, even if they did, most of the passengers wouldn't really know what was happening. You have to be able to see ahead to appreciate such things, not just out to the side as from a passenger cabin. If you seriously want to experience aerobatics, enquire at your local flying club. They will likely have an aerobatic light aircraft - but don't eat a big greasy meal before your flight!