Comment by fsckboy | Hacker News Reader

Comment by fsckboy | Hacker News Reader

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there's film of Tex Johnston's Dash-80 barrel roll https://www.youtube.com/watch?v=AaA7kPfC5Hk

many years later, Boeing Chief Test Pilot John Cashman stated that just before he piloted the maiden flight of the Boeing 777 on Jun. 12, 1994, his last instructions from then Boeing President Phil Condit were “No rolls”. -- anecdote from https://theaviationgeekclub.com/that-time-tex-johnston-barre...

I wonder why "the suits" at Boeing are so against the barrel rolls? The pilots all agree it's not that big a deal, not dangerous, and anybody watching is going to love it.

this article https://www.straightdope.com/21341407/is-it-possible-to-loop... says that the bigger the plane, the more dangerous because it will roll more slowly, and during parts of the roll particularly 90 degrees off "flat" there is no lift and you're going to be falling.

I'm reminded of the tragic crash of a B-52 illustrating a similar circumstance, and this was the pilot's last flight before retiring https://www.youtube.com/watch?v=E6io8Tjv7xk

A barrel roll is one thing to perform in a transport category jet, it is a ~1G maneuver when performed correctly. A loop is altogether different. My good friend Bernardo Malfitano, https://www.understandingairplanes.com/Bernardo-Malfitano.ht... , when he worked as a Structural Methods & Allowables engineer at Boeing, was also an aerobatics pilot on the side and put on a fantastic brown-bag lunch presentation entitled "Can you loop a 747?" where he demonstrated how he calculated the weight, altitude, airspeed, and configuration points to theoretically loop a 747 while staying within the certified load limits, then did a stepwise simulation of the results. It would theoretically be possible, but it would be very close to the limit of the airplane's capabilities.

Found it - "Aerobatic Capabilities of “Marginally Aerobatic” Airplanes" - scroll down to "The Physics of Aerobatics" and click "Paper", toward the end there is a detailed summary of how a transport jet could just barely do a very ugly loop. https://www.understandingairplanes.com/online.html

“Marginally Aerobatic”

Gotta love the understatement there.

§ 91.303 Aerobatic flight. No person may operate an aircraft in aerobatic flight - (a) Over any congested area of a city, town, or settlement; (b) Over an open air assembly of persons; (c) Within the lateral boundaries of the surface areas of Class B, Class C, Class D, or Class E airspace designated for an airport; (d) Within 4 nautical miles of the center line of any Federal airway; (e) Below an altitude of 1,500 feet above the surface; or (f) When flight visibility is less than 3 statute miles. For the purposes of this section, aerobatic flight means an intentional maneuver involving an abrupt change in an aircraft's attitude, an abnormal attitude, or abnormal acceleration, not necessary for normal flight.

The Dash-80 roll was a 1-G maneuver that didn't strain the airframe at all. Local legend says that single barrel roll was enough to convince an airline industry skeptical of jet aircraft to open their checkbooks. Boeing -- in the person of Tex Johnston -- changed the world that day.

The only thing I can think is that it looks dangerous to casual observers, and that's the furthest thing Boeing and the airlines that purchase from them want potential passengers thinking.

Based on my “flight” experience in MSFS and various other games, you have to start high enough to complete a barrel roll, and you have to have good control surface authority that allows such deep rolls. At some scale it becomes hard to start high enough and finish it quick enough.

It’s not a big deal in a clean F-15C to start a barrel roll, change minds, and add a full right deflection for 1s to recover to a level flight. But in a larger and non-manauver-oriented planes like a 747, you might find out that the aircraft under present circumstances cannot command more pitch or roll rates to transition from a high-speed inverted descent to a desired positive climb situation before the altimeter indication would reach zero or below. The latter was not so fun.

Overall, I think it’s reasonable that “the suits” were not embracing it. The test pilots made their point, the world witnessed it, any further attempts weren’t strictly necessary, and frankly would have been scary.

Thank you for sharing this, I had never seen it even though I knew the story. I love how excited Tex is describing the 707. "We had an airplane that was going to shrink the world by a factor of two." the whole idea drips with 1950s techno-optimism.

The Fairchild B-52 crash isn't really comparable to the 707 roll. That was at a much lower altitude and a far more aggressive maneuver.

Tex Johnston's first flight was in 1925 with the age of 11 on a "barnstormer". At the time where the first flight regulation appeared in the US.

Back then "flight acrobatics" beside showing off the skills of a pilot was the art of "selling" planes/flying and making it popular after all the "Jennies" were sold off (and the pilots laid off) by the government after WWI[0] for essentially pennies: about $200 (~$4.000); production cost initially at $5.000 (~$100.000). Civil aviation "mass-adopted".

So, by selling a 707 with a barrel roll is as old school as it gets.

[0]https://web.archive.org/web/20150324051634/http://www.southe...

Even if intellectually you know it's totally safe, it's still something the plane was not explicitly designed to do and literally will never be used for again. I can understand the "oh my god what are you doing" reaction feeling a lot stronger than "I guess he must know what he's doing".

Thank you - I had never seen it. This is great.

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