Anyone who has ever attended an air show has witnessed the death-defying acrobatics of the pilots. But one maneuver stands out as a crowd favorite: the barrel roll, in which an aircraft performs a complete 360-degree rotation in mid-air.
It should come as no surprise that completing this exercise is no easy task – even in a small stunt plane or fighter jet – and requires an experienced pilot to complete it. But is it possible to perform a barrel roll in something larger, such as an airliner?
Richard P Anderson — a pilot, aerospace engineering professor and director of the Eagle Flight Research Center at Embry-Riddle Aeronautical University in Florida — said this is the case and even knows people who have evidence of it.
“I know people with videotapes alone [doing barrel rolls]”Anderson told Live Science.
Perhaps the most famous pilot to ever do so in a commercial aircraft was Alvin Melvin “Tex” Johnston, a test pilot for Boeing. In the summer of 1955, Johnston took a four-engine Boeing 367-80 (also known as the Dash 80) for a spin—literally.
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To impress Boeing executives watching from a yacht on Lake Washington near Seattle, the “maverick pilot” performed two barrel rolls as well as a chandelle, a stunt in which a pilot does a 180-degree Turn combined with a climb, according to the magazine Los Angeles Times. That Monday, Johnston’s boss called him into his office and asked him what he was doing. Johnston reportedly replied, “Selling airplanes.” Airplane and pilot magazine.
So how did he successfully execute a barrel roll on such a large aircraft? Anderson said the size of the aircraft is not as important as the pilot’s ability to mitigate the G-forces applied to the aircraft during taxiing.
“The physics are the same regardless of the size of the aircraft,” Anderson said. “In a barrel roll, the pilot is trying to keep the G-load on the aircraft at about 1g. In other words, pretty close to what we feel here on Earth.”
To complete the maneuver, the pilot must execute the roll while simultaneously pitching the aircraft’s nose up and then dropping down – all while flying the aircraft at cruising speed, which is about 550 to 600 mph (885 to 965 km /h). , as if it were flying through a barrel, they say Flying magazine.
“The only real limiting factor in a barrel roll is the speed at which the aircraft rolls,” Anderson said. “In a barrel roll, you pull the nose up, and as you execute the roll, you drop the nose, which allows you to maintain that low-stress environment. If the nose drops as you roll, that’s what you’ve got.” What we need to do is roll the plane all the way around before the nose goes too far down. As long as the plane has a reasonable roll rate, physics says this is possible for any plane.
David Haglund, a veteran U.S. Air Force pilot and lecturer at the Museum of Flight near Seattle, added that the amount of airspace available to conduct the flight was also important, especially with a large aircraft compared to a small one Cessna.
“Before performing this maneuver, a pilot would check the available airspace,” Haglund told Live Science in an email. “On a commercial aircraft, a barrel roll would require an altitude block of 2,000 feet [600 meters] above and below level altitude (4,000 feet total) [12,000 m] be on the safe side.”
But while it’s physically possible, some manufacturers have built a restriction into large, modern aircraft, perhaps to deter future Tex Johnstons from performing similar acrobatic feats, especially with passengers on board.
“The Airbus does not give the pilot the ability to roll beyond 60 degrees of bank without disabling part of the automatic flight system that governs the operating envelope of the aircraft,” said Haglund, who has experience flying A330 and A350 models.