I recall an incident in the 70’s were the pilot of passenger-free 747 or maybe a 727 managed to perform a loop d’ loop. I’m pretty sure he got in a lot of trouble, and that there was a film of the event.
Any Dopers got more info on this incident?
Or on the correct spelling of loop d’ loop?
I think it was a 727 and I think he did a barrel roll (rolling the plane along the long axis) and a loop. I’m pretty sure a commercial airliner is incapable of a loop. They don’t have nearly enough power to achieve that without stalling and they’d likely rip the wings off before gaining enough speed to accomplish this by diving for the ground.
Still, I think the engineers were reasonably certain a barrel roll wasn’t possible either but the guy did it.
As to whether or not the guy got in trouble I don’t think so. I seem to remember that he did this in front of potential buyers and since he succeeded the buyers were suitably impressed making the execs pleased. IIRC the test pilot had a face-to-face with Boeing’s CEO after this where the CEO was unpleased and pleased at the same time.
Of course, this is all from a fading memory and I recently looked for a cite to this and couldn’t find one so take it with a grain of salt.
The Master addressed the matter in Is it possible to loop or roll a 747 jet?
Short answer: Boeing 707. (It was a long time ago–my memory says it was one of the prototypes, but I’m still looking for confirmation. I know that one of the test pilots barrel-rolled the 707 prototype, but I’m not sure of the loop.)
The aircraft maneuver is called a loop.
A loop the loop (loop-de-loop for the fricatively challenged) is an old amusement park ride.
Oops…scratch the bolded part. The guy only did a barrel roll if he even did that.
Unarguably the most famous of Tex Johnston’s maneuvers, indeed one of the most well-known feats in all of aviation history, was executed at a demonstration flight at which over 200,000 spectators were present. Of the audience who was fortunate enough to see Tex’s unprecedented and unauthorized Boeing 707 barrel roll, he comments, “The collective number of aircraft industry attendees was probably a first in aviation history and presented a historic opportunity to promote the Dash 80.” In his typically matter-of-fact narrative style, he simply comments, “I pulled the nose up and executed a leisurely climbing left barrel roll, and then began the descent to Lake Washington.” If you’ve ever heard this anecdote, you now know that it was accomplished by a Spartan graduate!
Happened during the Gold Cup hydroplane races in Seattle, August 1958.
A barrel roll is a nominal 1 positive G maneuver, not very stressful. I’ve seen a film clip taken in the cabin of Bob Hoover’s Aero Commander during a barrel roll. A glass of water never spilled. I’ve seen the clip of Tex Johnson barrel rolling the dash 80, pretty cool.
FWIW a barrel roll is not done on the airplane’s axis. It’s more of a spiral path around an axis well off the inside wingtip. That’s how it’s less stressfull. The airplane and all the stuff in it never feels upside down. A slow or aileron roll, is done around the airplane’s axis and probably would have damaged an airliner.
I wonder what would have happened to Boeing, if he had crashed. Certainly less orders would have been placed.
OK -
we have two incidents here -
Yes, the 707 prototype was rolled for the airline execs - stuff of legends.
Yes, circa 1979, somebody rolled a 727 filled with passengers - he CLAIMED that the manuver was “uncommanded” - the plane just did it all by itself. yeah, right.
Don’t know what happened to him - remember the newspaper shot of the plane - sheet metal hanging off.
(hope he at least won the bet)
Cecil’s article (linked above by tomndebb) mentions that Boeing suspects one of its airliners just might manage a loop but since it would be extremely dangerous no one has been willing ot test it (I’m paraphrasing).
Just how good are the flight simulators used to train pilots? Will they accurately reflect the stresses on the plane and ‘break apart’ (virtually speaking) if a pilot puts too much stress on the plane? Even if we skip the break apart stuff could a loop performed in one of these simulators constitute a good bet for the ability (or non-ability) of a given airliner to manage a loop? Heck, I’d find it hard to believe no one has attempted this in a simulator…sooner or later you’d think someone would give it a shot just 'cuz.
Much as I might like to see someone in a simulator try this, I think that the events of 9/11 have made flight simulator operators REALLY leery about what goes on in their simulators.
Not in a loop. Nobody’s ever done it, so they don’t have the information to put in the sim program.
Pretty damn good.
Not THAT good, in my experience.
I have, in a simulator for a Beech 1900 airliner. I have rolled it, looped it, and spun it. I plummeted towards the ground with one engine feathered and the other in reverse. I flew it like I stole it, and the thing never complained.
The sim is amazing for how it duplicates normal flight operations. If you set the weather to rain, you can hear it hitting the windshield. You can simulate how the planes handling is affected by passengers getting up and walking around. But for some reason the line is drawn at the airplane structure starting to fail. I don't know why. I suspect there are sims made just for this purpose, or it costs extra and our sim just doesn't have it.Stresses on an airplane during flight are relatively easy to calculate, and the airplanes themselves are tested to destruction (or to the point where gets silly).
It’s probably not in the sim program because, for the most part, it’s not worth simulating.
How 'bout NASA’s 0g simulator, the “Vomit Comet”?
Isn’t that a 747?
I’m sure it’s structural integrity has been beefed up enough, after all, it must handle several g’s coming out of each 0 g arc.
Maybe and maybe not. Who’s to say what stresses occur to a plane under various conditions. In the story of the Gimli Glider it mentions that the pilot threw the plane into a “vicious sideslip”. In this case the plane held together and for all I know wasn’t close to breaking apart. However, I mention it to show that all sorts of weird things may happen while flying and perhaps if a pilot knew ahead of time from simulator training that ‘maneuver X’ will almost certainly break the plane he/she may not try it and look for other options (assuming in such a situation they have time to think and not just react).
As to the structural integrity of a plane I thought WWII planes were rated as to maximum dive speeds after which point the chances of the plane falling apart were significant. I’ll grant we have better materials today than back then but an airliner generally isn’t built with combat in mind either whereas a fighter is expected to encounter extreme flying. Also, IIRC I heard a report on the final minutes of TWA flight 800 that crashed off of New York. Part of the final sequence of events (post explosion) was the plane diving for the ocean and the wings ripping off as it fell.
I mention all of this not as an expert but to illustrate the notion I have that while airliner structures are strong they aren’t invulnerable to breaking under extreme conditions found in flight. Conditions such as diving a 747 towards the ground in order to gain enough airspeed to pull off an over the top loop (could the plane break the sound barrier in such an attempt and the shockwave add significantly to tearing the wings off?).
The Vomit Comet is a KC-135, basically a 707.
You could be correct, but it was my impression that rating dive speeds had more to do with compressibility issues (where the controls froze) rather than structural failure. Most of the planes had a fairly well-known terminal velocity and it was pretty much useless to try to get them to exceed it (as any pilot who ever tried to outdive a P-47 found out). The P-47 and, later, the P-38 were the first planes to suffer control failure due to compressibility. Republic added dive brakes to the P-47 so that the pilot could slow it down enough to reduce the compressibility problem, but I never heard of one shedding its wings or tail.
You can’t loop a large jet for the simple reason that you can’t gain enough energy to complete the manoever. There isn’t enough energy margin from cruise speed to gain a lot from diving to structural limits, and the engines aren’t powerful enough to do it.
In other words, if you dove the plane to its never-exceed speed and then pulled up into a perfect, smooth 3-G loop at full power, the jet wouldn’t make it around. Depending on how it fell out of the manoever it might well exceed structural limits in the recovery.
I’ve heard that the engines in those birds are a lot more impressive than they are given credit for. As to whether the planes themselves would survive the engines’ showing their stuff off with the structural integrity largely intact, who knows?
My guess is that if you climbed to the ceiling in a sample set of 747s and did a leisurely (inside) loop in each, the machine would do it, with a wide range of possible structural damages, and some would not make it, while some would not only make it but would come out of it just fine.
Of course that’s an inside loop, where you dive and then pull up. It’s my impression that there are far fewer aircraft that are capable of doing it the other way (outside), where you dive and then push in in order to do your loop.
An related tangent … The US/China incident last year involving a Chinese fighter and an EP-3 surveillance aircraft resulted in apparent aviation firsts. The EP-3 airframe is a descendant of the Lockheed Electra. It’s about the same size as a 737. According to the pilot, Shane Osborn, before this accident, an aircraft of that size had never been rolled nor had one ever recovered from inverted flight. I guess he never heard of the Dash-80.