Can you do a loop-the-loop in a passenger jet?

Is it possible to do aerobatic stunts, such as a loop-the-loop or a barrel roll, in large passenger aeroplanes such as Airbus A380s and Boeing 747s?...
10 May 2009

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Question

Can you do aerobatic stunts like a loop-the-loop or a barrel roll in large aeroplanes such as Airbus A380s and Boeing 747s?

Answer

We put this firstly to Disk Schleh, of Boeing Commercial Airplanes in Seattle, Washington:

Well a large passenger jet such as the Boeing 747 or almost, almost any large passenger jetliner was not designed nor was it tested, nor was it certified to perform aerobatic manoeuvres like a loop-the-loop or a barrel roll.

Certainly the wings of the airplane would be put under quite a bit of stress and some of the tail structure and so forth, doesn't mean it couldn't do it but they were not designed that way and they were certainly not certified with that in mind. In the early days of the jetliners when the jetliner was being developed at the Boeing company in the 1950s there was a prototype called the 367-80, that was the 707 prototype and the original test pilot on that airplane was Tex Johnston and one day he was asked to fly the aeroplane over a major event here in Seattle which was called the Hydroplane Races, so he did in fact fly the aeroplane at a fairly low altitude over the crowd but then he decided to really impress the crowd so he did a barrel roll with that airplane, much to the surprise of the Boeing officials who were watching from down below.

But he felt that it was a good demonstration of the aeroplane's capability but he was strongly reminded never to do that again and indeed, as far as I know, it has not been done again at least certainly not as part of our test operation here at Boeing.

We then asked Peter Merton, Resident Research Officer at the Imperial War Museum at Duxford. The simple answer is frankly, no. The critical points about, well not just modern passenger jet airliners but airliners built in the past during the 20s and 30s coming forward in time is that they are designed to be load carriers. So they are designed to withstand the quite severe adverse weather conditions, to be able to carry passengers and cargo in safety and especially now-a-days of course with the long-range jets to carry a lot of fuel.

So they are perfectly capable of some quite violent manoeuvres in terms of things like steep turns and I have seen them being flown with a very graceful positional flying, doing quite steep dives and climbs but not of course with passengers or cargo on board. This is the big difference that they are designed to be strong and robust and particularly to have a good survivability factor in case of an accident or a crash landing whereas the purpose designed aerobatic aircraft or even other aircraft types like fighter aircraft, can cope with the stresses and that is the critical difference really.

Comments

A proper barrel-roll (NOT a snap-roll) is a 1G maneuver. No worries for any airframe, provided you are at a safe altitude.

"It was a promotional stunt that in today’s dollars used a $144 million investment by Boeing.

And it was done without the knowledge of Bill Allen, then president of the company, who was watching. And fuming.

He was not a happy man. The firm’s future was on the line. No time for tricks.

But 60 years ago, on Aug. 7, 1955, Boeing’s chief of flight testing, the legendary Alvin “Tex” Johnston, pulled an impressive stunt in the prototype of the Boeing 707.""
... snip ...
"...It’s been written that (Boeing President) Allen had contemplated firing (Tex) Johnston. The morning after the (707 prototype) barrel roll, Johnston was told to go to Allen’s office, where other higher-ups also were waiting. Allen asked, “What did you think you were doing yesterday?” Johnston replied, “Selling the airplane.”

In his view, Johnston had a very rational explanation for the stunt, and why it was so safe.

Here is the explanation in his book, “Jet-Age Test Pilot,” although it helps to have piloting knowledge to understand it: “The airplane does not recognize attitude, providing a maneuver is conducted at one G. It knows only positive and negative imposed loads and variations in thrust and drag. The barrel roll is a one G maneuver and quite impressive, but the airplane never knows it’s inverted.”

Allen mulled that over and responded, “You know that. Now we know that. But just don’t do it anymore.”"

https://www.seattletimes.com/seattle-news/60-years-ago-the-famous-boeing...

You can see actual footage, in-cockpit, of a smaller airliner doing a couple of perfect 1G barrel-rolls here:

https://www.youtube.com/watch?v=V9pvG_ZSnCc

So that doesn't answer the question at all. Why not ask a engineer and just get a simple answer?: a) Yes, the aircraft would be able to do the maneuvers without crashing or b) No, the thing would rip apart in the air.

I think this bit of the answer suggests that you could - but probably shouldn't - do it...

"...in the 1950s there was a prototype called the 367-80, that was the 707 prototype and the original test pilot on that airplane was Tex Johnston and one day he was asked to fly the aeroplane over a major event here in Seattle which was called the Hydroplane Races, so he did in fact fly the aeroplane at a fairly low altitude over the crowd but then he decided to really impress the crowd so he did a barrel roll with that airplane, much to the surprise of the Boeing officials who were watching from down below."

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