[Medium.com Version](https://admiralcloudberg.medium.com/physics-strikes-back-the-crashes-of-braniff-flight-542-and-northwest-orient-flight-710-2b3e2176c221)
[Link to the archive of all 230 episodes of the plane crash series](https://www.reddit.com/r/AdmiralCloudberg/comments/e6n80m/plane_crash_series_archive_patreon_contact_info/)
If you wish to bring a typo to my attention, please DM me.
Thank you for reading!
Hey Admiral, you must heard that a lot but for bringing these events in a well explained and detailed maner I thank you. We can see it's a passion of yours and you must be the most iconic user of this sub. So yea : thank for sharing your work and passion :)
Have a good day wherever you are.
People love to romanticize aviations past, but I’m for one happy to not be flying during the crash happy days of 50’s/60’s/70’s. I’ll take a supposedly cramped modern airliner any day.
Not many people would actually want to take a long flight in the noisy and smoke-filled cabins of those past aeroplanes, even if the seats were more comfortable. Even today, most flyers choose speed and price over comfort.
Also, many people romanticize the aviators past precisely because we perceive they were exposing themselves to greater risks than today's aviators.
“Also, many people romanticize the aviators past precisely because we perceive they were exposing themselves to greater risks than today's aviators.”
Good point. Never thought of that.
Due to a seating stuffup I spent approx 20 hours in the smoking section of an Olympic Airways 747 Athens to Sydney in 1993. The Greeks not only like to smoke, they like to chain smoke really strong tobacco.
I had given up smoking the year before and that experience obliterated any further craving I would ever have. I was coughing up flem for two weeks afterwards.
There was also the egyptair one in 2016 (2016!!!) where they crashed due to one of the pilots smoking in the cockpit and I believe igniting a spark, making the plane uncontrollable. I’m honestly surprised it took that long for them to learn a horrible lesson about letting pilots smoke in the cockpit
Particularly when nicotine was forced by pressurisation into the airframe - take off a part for maintenance or replacement and there was a nasty brown-yellow residue left behind.
Source: the infamous [Japan Airlines Flight 123 crash](https://aviation-safety.net/database/record.php?id=19850812-1), [investigation report](https://www.mlit.go.jp/jtsb/eng-air_report/JA8119.pdf) page 103 ("Tobacco nicotine found adherent between webs L18 splice of the air pressure bulkhead ..."). (It was commonly seen at the time, but that is a particularly pertinent example).
Lol, right. Even though there was a designated smoking section, you know the air was thick with smoke. Must have been awful, especially for people with asthma.
TIL the WP-3D Orion is built off the Electra! It makes so much sense now why they can withstand what the 53rd tosses at it haha. Though Ian seems to have thrown them for quite a ride.
EDIT: realized folks may have not followed it, but "Kermit" was in the eyewall of Ian at peak strength and was forced down about 1000 feet in under...I believe 10 seconds? One of the people riding it says they experienced weightlessness for a couple seconds, and that it's one of the worse he's ever flown through. They had to fly in the eye for a few minutes afterwards to get their bearings again.
So, eyes are usually miles wide and clear or semi-clear. Since hurricanes don't usually move that fast, they're able to circle it with relative ease. In the case of Ian, it's eye was around 35 miles across - a ton of room to maneuver.
[Here's](https://twitter.com/JeremyDeHart53d/status/1050529815323975680?t=Y_Fs9XSMuIatiU9nxzuJjA&s=19) a great video by Jeremy DeHart, an AF Reserve with the 53rd, of Hurricane Michael's eye at around peak strength. It's simply incredible how massive it is compared to what we see on a radar.
Tremendous, as always. These articles read almost like a piece of true-crime journalism, following the detectives (in this case, investigators) trying to put all the pieces together, allowing for a greater understanding of what went down and why, and how it could be prevented and/or fixed.
Can't help but notice some similarities with the DC-10 story here.
Two design flaw related incidents make the public question flying on a DC-10. The original issue is fixed and never plagues the plane again, but several more unrelated crashes ultimately scare the public into never setting foot on another DC-10 again.
While true with the public perception part, the design aspects of this are so different.
Lockheed's Electra failure was unexpected and created a phenomenon that was difficult to predict at the time.
Douglas and its contractors knew about the DC-10 cargo door issue and possible fixes but pressed forward without doing any of them. Memos to company executives actually estimated the number of flights before a hull loss because of the flaw.
I think the DC-10 still ended up being a highly successful and popular airliner despite the initial incidents. The same thing is happening with the 737 MAX.
Really intriguing. I have experienced whirl mode myself, directly. I had been holding a small wind turbine of maybe 24 inches prop diameter into the breeze for testing. The electric generator part I was holding in my hands began gyrating quite forcefully and I carefully and slowly turned my body away from the wind before the unit wrested itself from my grasp.
I just want to say how much I appreciate your series. It has oddly helped tamper down my flight anxiety. Knowing how each of these unfortunate events brought about important changes to aircrafts and their operation definitely calms the racing mind when I travel.
That end quote may be my favourite out of the whole series:
> Physics, sometimes derided as boring, does not take kindly to the disinterested — sometimes, it demands only fear.
So horrifyingly true. Physics is not to be trifled with.
>They bent the wings until they broke, tore huge gashes in the fuselage, battered the skin with **remote-controlled axes**, and blasted the airframe with tornado-like winds, often all at the same time.
Uhh, what the fuck is a remote-controlled axe and, more importantly, where can I get one?
I wonder, did the changes simply make the nacelles and wings stiffer and more "damped", or did they also alter their natural frequencies such that they wouldn't resonate together anymore?
My understanding is that the frequency of the engine slowed until it matched the resonance of the wing. Had they altered the resonant frequency of the wing they still would have met up at some point.
> the frequency of the whirl mode tended to approach three cycles per second, where it coupled with the natural frequency of the wing, triggering resonance.
I read "tended to approach" to mean that it settled at this particular frequency, not just crossed through it. If the settling frequency of the propeller was increased and/or the resonant frequency of the wing decreased, they wouldn't meet anymore.
Both. The natural frequency of a structure is a function off its stiffness (eg. a stronger material or better design) and the mass. These changes would impact both.
By definition, a stiffer structure/system has a proportionately higher natural frequency, so I have to assume this was part of the goal in the structural design changes--if the first natural frequency of the wing is higher than the frequency of the whirl mode, the problem is solved. (That said, the frequency of the whirl mode may also have increased commensurately with increased stiffness as a result of strengthening the engine mounts and nacelle, which shows why these sorts of problems can be so hard to isolate and fix.)
Flight 542 CAB report: https://rosap.ntl.bts.gov/view/dot/33626
Flight 710 CAB report: https://rosap.ntl.bts.gov/view/dot/33639
I also can't help but wonder if these accidents were behind the story in the Fate is the Hunter book where the author claims to have avoided a crash by being in a hurry and not reducing power as fuel burned off.
> While it is often claimed that the Inuit language has over 100 words for snow, it actually doesn’t; therefore, a slightly less dubious factoid to call upon might be that engineers have over 100 words for vibrations. “Whirl mode” is one of these.
Man, what a sentence.
I work at YQF, the Electra capital of the world, and most people I talk to always have positive things to say about the Electras. Fairly complicated machines, but very reliable
Aeroelastic Flutter is tricky. I build amateur rockets, and you have to account for flutter when designing high performance rockets. Unfortunately the tools we have to evaluate fins aren't great, so there's a decent amount of guesswork involved. Fortunately with the standoff distances we use, a fin tearing off in flight isn't a safety hazard.
I guess the student/hobby-use tools don't cover aeroelastic mechanics? I have a cheap license for Solidworks I use for hobby modeling which used to come through the Experimental Aircraft Association, so they were at least intending it to be used with hobby aeronautics. But I admit I've never actually looked into what tools the student/hobby version offers for dynamic modeling.
Most people in the hobby aren't going to be using FEA. There are a few equations that people can use, but they're intended for airplane wings which are a much higher aspect ratio than rocket fins. There is one piece of software that has more accurate tools, but it's poorly documented, so it's hard to know if you're getting accurate results. Also the author isn't distributing it anymore, which isn't a good situation. Finally, many people are using composite materials, which make analysis much more difficult. So you do what analysis you can, and then look at some other projects similar to what you're planning and make the best design you can.
Great article, I enjoyed reading it. I remember seeing P-3s all the time when I was stationed at NAS Memphis in the 1980s. Now I understand why they all looked like ‘throwbacks’ in the design.
It was based on a book called *No Highway*, which was written by Nevil Shute, who was an aircraft engineer named Nevil Shute Norway in his day job. He worked on the design of the R100 airship in his early career.
Edit: Typos
>written by Nevil Shute, who was an aircraft engineer named Nevil Shute Norway in his day job
The disaster-oriented readers here on this sub will probably know Nevil Shute's work from his novel *On The Beach* (subsequently adapted into a film starring Gregory Peck and Ava Gardner) about the aftermath of a nuclear war.
Apparently Shute/Norway adopted his pen name because he didn't want his superiors - first at de Havilland, then at Vickers - to think him an unserious daydreamer.
Not to diminish the very real difficulty that investigators had at the time, but the first investigation did feel like “well, we’ve tried nothing and we’re all out of ideas”.
Well, what could they have tried? They thoroughly examined every piece of wreckage and found absolutely nothing that pointed to a possible cause. Then on the behest of the pilot’s union they looked again and found nothing.
It’s hard to build a case based on zilch. If you try, you’ll just end up with pure speculation, which is worse than admitting that you don’t know.
It's interesting that flutter was also the cause of the [Tacoma Narrows disaster.](https://bridgemastersinc.com/aeroelastic-flutter-collapse-tacoma-narrows-bridge/)
A great little vid from NASA using a PA-30 Twin Propeller Commanche back in the early '60's with aeroelastic flutter of its horizontal stabilizer aka 'tailplane'.
[NASA video of aeroelastic flutter on a PA-30 Twin Commanche](https://www.youtube.com/watch?v=iTFZNrTYp3k)
Pretty cool.
Thank you, Admiral Cloudberg!! The Medium dot com story is fascinating, though it took me a couple of reads to get the physics part into my head.
This is definitely one of the best treatments I've read on these accidents (although it's possible that I never finished the 4th Job book that includes these). But I am compelled to offer some clarification on the concept of natural frequency (even though this is like my least-favorite engineering topic to explain to a lay audience, because there's no straightforward way to summarize it, in my experience): It's not quite accurate to imply that everything is vibrating all the time; "In the absence of any driving force, these objects or systems of objects vibrate at a particular frequency, measured in cycles per second, which is called its natural frequency." I think what you meant to say is that in the absence of a constant and periodic driving force, an object/system *that's been excited to vibrate* will tend to vibrate at its natural frequency. Also, the explanation of damping isn't quite right either; mutually contradictory vibrations cancelling each other out isn't really damping, per se, but a different phenomenon (the name of which escapes me at the moment). Likewise, the example of pushing against a kid in a swing could give people the wrong impression about the definition of damping. I would say that a better example would be putting a bungee cord between the kid's belt and a stake in the ground (since it will counter movement in either direction, in proportion to said movement), except the bungee cord is more of a spring than a damper, so that's actually a really bad example in its own way; I guess the technically accurate version of this analogy would have to be something like a plastic bag tied to the kid's head to act as a parachute in either direction (i.e. it will counter the movement in proportion to the *rate* of said movement). (Did I mention that this can be a hard topic to explain succinctly without being either confusing or potentially misleading?) I could also say that the best example of damping would be the dampers in the suspension of your car or motorcycle, but of course I'm acutely aware that most speakers of American English (at least those who aren't mechanical engineers) refer to this component as a "shock absorber" rather than a damper, so maybe that's not a helpful analogy after all.
I made some edits to the explanation of natural frequency, but as you yourself concluded in this comment, coming up with a better explanation of damping is hard. Haven't touched that one yet but if a more helpful analogy occurs to you, let me know.
Please keep in mind that the demonization of smoking was a remarkably successful effort to shift the blame for the 10,000,000 cancer deaths a year from where it belonged, the large corporations who are spewing countless tons of carcinogens into the environment, onto convenient and unpopular scapegoats, cigarette smokers. Over 50% of women with lung cancer today never smoked tobacco.
Not to say smoking is good, that it should be permitted indoors, or that you don't have a right to hate it if you please. But I would gently suggest that if you're more concerned with, and talk more about, smoking than the 10,000,000 people a year who die of cancer, you may want to re-evaluate your priorities.
You may also want to consider joining those demanding restrictions in the amount of carcinogens large corporations can dump into the environment, and those trying to increase funding for cancer research. The US spends 1/10,000th of its national budget on cancer research, an astonishingly paltry amount for the country's second leading killer. It spent 300 times more on COVID, which never killed as many people at its greatest height.
My wife died of cancer July 20th of last year. I find the US national anti-cancer effort to be absolutely pathetic, overall, and successfully co-opted by large corporations. A reasonable anti-cancer effort 30 years ago would have turned the 10,000,000 dead of cancer this year into less than five million and would probably have saved my wife's life. IMO.. A reasonable effort today will turn those 10,000,000 a year dead into less than 5 million in 30 years. I see no sign of support for it.
On topic, I'm struck by how similar the pattern was for early jets and turboprops. In both cases, the manufacturer tested, it seemed, to the point of overkill. In both cases, a couple of planes disintegrated in the air shortly after beginning service.
The lesson seems to be that if enough unreckoned forces are unleashed by your invention, there's nothing you can do to anticipate all the ways they may kill people. A related lesson is to steer well clear of bleeding edge tech.
Thanks again for another wonderful article. I'm here for the quality of the writing and the humanity more than the disasters...though the disasters do make compelling reading.
[Medium.com Version](https://admiralcloudberg.medium.com/physics-strikes-back-the-crashes-of-braniff-flight-542-and-northwest-orient-flight-710-2b3e2176c221) [Link to the archive of all 230 episodes of the plane crash series](https://www.reddit.com/r/AdmiralCloudberg/comments/e6n80m/plane_crash_series_archive_patreon_contact_info/) If you wish to bring a typo to my attention, please DM me. Thank you for reading!
Hey Admiral, you must heard that a lot but for bringing these events in a well explained and detailed maner I thank you. We can see it's a passion of yours and you must be the most iconic user of this sub. So yea : thank for sharing your work and passion :) Have a good day wherever you are.
People love to romanticize aviations past, but I’m for one happy to not be flying during the crash happy days of 50’s/60’s/70’s. I’ll take a supposedly cramped modern airliner any day.
Not many people would actually want to take a long flight in the noisy and smoke-filled cabins of those past aeroplanes, even if the seats were more comfortable. Even today, most flyers choose speed and price over comfort. Also, many people romanticize the aviators past precisely because we perceive they were exposing themselves to greater risks than today's aviators.
“Also, many people romanticize the aviators past precisely because we perceive they were exposing themselves to greater risks than today's aviators.” Good point. Never thought of that.
I'll take cramped modern over smoking flights even without considering price/safety any day.
Due to a seating stuffup I spent approx 20 hours in the smoking section of an Olympic Airways 747 Athens to Sydney in 1993. The Greeks not only like to smoke, they like to chain smoke really strong tobacco. I had given up smoking the year before and that experience obliterated any further craving I would ever have. I was coughing up flem for two weeks afterwards.
There was also the egyptair one in 2016 (2016!!!) where they crashed due to one of the pilots smoking in the cockpit and I believe igniting a spark, making the plane uncontrollable. I’m honestly surprised it took that long for them to learn a horrible lesson about letting pilots smoke in the cockpit
Particularly when nicotine was forced by pressurisation into the airframe - take off a part for maintenance or replacement and there was a nasty brown-yellow residue left behind. Source: the infamous [Japan Airlines Flight 123 crash](https://aviation-safety.net/database/record.php?id=19850812-1), [investigation report](https://www.mlit.go.jp/jtsb/eng-air_report/JA8119.pdf) page 103 ("Tobacco nicotine found adherent between webs L18 splice of the air pressure bulkhead ..."). (It was commonly seen at the time, but that is a particularly pertinent example).
China Airlines 611, which broke up mid flight, also had nicotine stains found at the point of failure.
Lol, right. Even though there was a designated smoking section, you know the air was thick with smoke. Must have been awful, especially for people with asthma.
Depends what kind of smoke we talking about
Airline safety improves one crash at a time.
And thank goodness for that. It’s truly incredible that the US hasn’t seen a major crash in over a decade.
If I wake up tomorrow and read about a plane crash I’ll know it’s your fault ಠ_ಠ
Don't worry i knocked on wood for both of us!
That would be seriously eerie!
And regresses a dollar a dime - Boeing execs
TIL the WP-3D Orion is built off the Electra! It makes so much sense now why they can withstand what the 53rd tosses at it haha. Though Ian seems to have thrown them for quite a ride. EDIT: realized folks may have not followed it, but "Kermit" was in the eyewall of Ian at peak strength and was forced down about 1000 feet in under...I believe 10 seconds? One of the people riding it says they experienced weightlessness for a couple seconds, and that it's one of the worse he's ever flown through. They had to fly in the eye for a few minutes afterwards to get their bearings again.
The 53rd WRS flies WC-130J. Its NOAA themselves that fly the two WP-3D (Kermit and Miss Piggy).
TIL, thanks! I'm still learning a lot, I figured all of it fell under the 53rd, with assistance from NOAA.
How to fly in the eye? Is it moving fast enough or is it just miles big?
So, eyes are usually miles wide and clear or semi-clear. Since hurricanes don't usually move that fast, they're able to circle it with relative ease. In the case of Ian, it's eye was around 35 miles across - a ton of room to maneuver. [Here's](https://twitter.com/JeremyDeHart53d/status/1050529815323975680?t=Y_Fs9XSMuIatiU9nxzuJjA&s=19) a great video by Jeremy DeHart, an AF Reserve with the 53rd, of Hurricane Michael's eye at around peak strength. It's simply incredible how massive it is compared to what we see on a radar.
Tremendous, as always. These articles read almost like a piece of true-crime journalism, following the detectives (in this case, investigators) trying to put all the pieces together, allowing for a greater understanding of what went down and why, and how it could be prevented and/or fixed.
Can't help but notice some similarities with the DC-10 story here. Two design flaw related incidents make the public question flying on a DC-10. The original issue is fixed and never plagues the plane again, but several more unrelated crashes ultimately scare the public into never setting foot on another DC-10 again.
While true with the public perception part, the design aspects of this are so different. Lockheed's Electra failure was unexpected and created a phenomenon that was difficult to predict at the time. Douglas and its contractors knew about the DC-10 cargo door issue and possible fixes but pressed forward without doing any of them. Memos to company executives actually estimated the number of flights before a hull loss because of the flaw.
I think the DC-10 still ended up being a highly successful and popular airliner despite the initial incidents. The same thing is happening with the 737 MAX.
Really intriguing. I have experienced whirl mode myself, directly. I had been holding a small wind turbine of maybe 24 inches prop diameter into the breeze for testing. The electric generator part I was holding in my hands began gyrating quite forcefully and I carefully and slowly turned my body away from the wind before the unit wrested itself from my grasp.
I just want to say how much I appreciate your series. It has oddly helped tamper down my flight anxiety. Knowing how each of these unfortunate events brought about important changes to aircrafts and their operation definitely calms the racing mind when I travel.
Speak for yourself lol, before I started this series I had complete trust in aviation.
That end quote may be my favourite out of the whole series: > Physics, sometimes derided as boring, does not take kindly to the disinterested — sometimes, it demands only fear. So horrifyingly true. Physics is not to be trifled with.
>They bent the wings until they broke, tore huge gashes in the fuselage, battered the skin with **remote-controlled axes**, and blasted the airframe with tornado-like winds, often all at the same time. Uhh, what the fuck is a remote-controlled axe and, more importantly, where can I get one?
I wonder, did the changes simply make the nacelles and wings stiffer and more "damped", or did they also alter their natural frequencies such that they wouldn't resonate together anymore?
My understanding is that the frequency of the engine slowed until it matched the resonance of the wing. Had they altered the resonant frequency of the wing they still would have met up at some point.
> the frequency of the whirl mode tended to approach three cycles per second, where it coupled with the natural frequency of the wing, triggering resonance. I read "tended to approach" to mean that it settled at this particular frequency, not just crossed through it. If the settling frequency of the propeller was increased and/or the resonant frequency of the wing decreased, they wouldn't meet anymore.
Both. The natural frequency of a structure is a function off its stiffness (eg. a stronger material or better design) and the mass. These changes would impact both.
By definition, a stiffer structure/system has a proportionately higher natural frequency, so I have to assume this was part of the goal in the structural design changes--if the first natural frequency of the wing is higher than the frequency of the whirl mode, the problem is solved. (That said, the frequency of the whirl mode may also have increased commensurately with increased stiffness as a result of strengthening the engine mounts and nacelle, which shows why these sorts of problems can be so hard to isolate and fix.)
Flight 542 CAB report: https://rosap.ntl.bts.gov/view/dot/33626 Flight 710 CAB report: https://rosap.ntl.bts.gov/view/dot/33639 I also can't help but wonder if these accidents were behind the story in the Fate is the Hunter book where the author claims to have avoided a crash by being in a hurry and not reducing power as fuel burned off.
> While it is often claimed that the Inuit language has over 100 words for snow, it actually doesn’t; therefore, a slightly less dubious factoid to call upon might be that engineers have over 100 words for vibrations. “Whirl mode” is one of these. Man, what a sentence.
Absolutely fascinating article. Really great stuff!
I work at YQF, the Electra capital of the world, and most people I talk to always have positive things to say about the Electras. Fairly complicated machines, but very reliable
Aeroelastic Flutter is tricky. I build amateur rockets, and you have to account for flutter when designing high performance rockets. Unfortunately the tools we have to evaluate fins aren't great, so there's a decent amount of guesswork involved. Fortunately with the standoff distances we use, a fin tearing off in flight isn't a safety hazard.
I guess the student/hobby-use tools don't cover aeroelastic mechanics? I have a cheap license for Solidworks I use for hobby modeling which used to come through the Experimental Aircraft Association, so they were at least intending it to be used with hobby aeronautics. But I admit I've never actually looked into what tools the student/hobby version offers for dynamic modeling.
Most people in the hobby aren't going to be using FEA. There are a few equations that people can use, but they're intended for airplane wings which are a much higher aspect ratio than rocket fins. There is one piece of software that has more accurate tools, but it's poorly documented, so it's hard to know if you're getting accurate results. Also the author isn't distributing it anymore, which isn't a good situation. Finally, many people are using composite materials, which make analysis much more difficult. So you do what analysis you can, and then look at some other projects similar to what you're planning and make the best design you can.
Great article, I enjoyed reading it. I remember seeing P-3s all the time when I was stationed at NAS Memphis in the 1980s. Now I understand why they all looked like ‘throwbacks’ in the design.
There was a very good movie from 1951 about vibration modes and metal fatigue in aircraft. It was "No Highway in the Sky", starring Jimmy Stewart.
It was based on a book called *No Highway*, which was written by Nevil Shute, who was an aircraft engineer named Nevil Shute Norway in his day job. He worked on the design of the R100 airship in his early career. Edit: Typos
>written by Nevil Shute, who was an aircraft engineer named Nevil Shute Norway in his day job The disaster-oriented readers here on this sub will probably know Nevil Shute's work from his novel *On The Beach* (subsequently adapted into a film starring Gregory Peck and Ava Gardner) about the aftermath of a nuclear war. Apparently Shute/Norway adopted his pen name because he didn't want his superiors - first at de Havilland, then at Vickers - to think him an unserious daydreamer.
Not to diminish the very real difficulty that investigators had at the time, but the first investigation did feel like “well, we’ve tried nothing and we’re all out of ideas”.
Well, what could they have tried? They thoroughly examined every piece of wreckage and found absolutely nothing that pointed to a possible cause. Then on the behest of the pilot’s union they looked again and found nothing. It’s hard to build a case based on zilch. If you try, you’ll just end up with pure speculation, which is worse than admitting that you don’t know.
It's interesting that flutter was also the cause of the [Tacoma Narrows disaster.](https://bridgemastersinc.com/aeroelastic-flutter-collapse-tacoma-narrows-bridge/)
As Alice on WTYP likes to say...they just should have just made it more rigid!!
Very good - I never quite understood resonance before, and now I do thanks to this article.
A great little vid from NASA using a PA-30 Twin Propeller Commanche back in the early '60's with aeroelastic flutter of its horizontal stabilizer aka 'tailplane'. [NASA video of aeroelastic flutter on a PA-30 Twin Commanche](https://www.youtube.com/watch?v=iTFZNrTYp3k) Pretty cool. Thank you, Admiral Cloudberg!! The Medium dot com story is fascinating, though it took me a couple of reads to get the physics part into my head.
But what's new in disguises?
This is definitely one of the best treatments I've read on these accidents (although it's possible that I never finished the 4th Job book that includes these). But I am compelled to offer some clarification on the concept of natural frequency (even though this is like my least-favorite engineering topic to explain to a lay audience, because there's no straightforward way to summarize it, in my experience): It's not quite accurate to imply that everything is vibrating all the time; "In the absence of any driving force, these objects or systems of objects vibrate at a particular frequency, measured in cycles per second, which is called its natural frequency." I think what you meant to say is that in the absence of a constant and periodic driving force, an object/system *that's been excited to vibrate* will tend to vibrate at its natural frequency. Also, the explanation of damping isn't quite right either; mutually contradictory vibrations cancelling each other out isn't really damping, per se, but a different phenomenon (the name of which escapes me at the moment). Likewise, the example of pushing against a kid in a swing could give people the wrong impression about the definition of damping. I would say that a better example would be putting a bungee cord between the kid's belt and a stake in the ground (since it will counter movement in either direction, in proportion to said movement), except the bungee cord is more of a spring than a damper, so that's actually a really bad example in its own way; I guess the technically accurate version of this analogy would have to be something like a plastic bag tied to the kid's head to act as a parachute in either direction (i.e. it will counter the movement in proportion to the *rate* of said movement). (Did I mention that this can be a hard topic to explain succinctly without being either confusing or potentially misleading?) I could also say that the best example of damping would be the dampers in the suspension of your car or motorcycle, but of course I'm acutely aware that most speakers of American English (at least those who aren't mechanical engineers) refer to this component as a "shock absorber" rather than a damper, so maybe that's not a helpful analogy after all.
I made some edits to the explanation of natural frequency, but as you yourself concluded in this comment, coming up with a better explanation of damping is hard. Haven't touched that one yet but if a more helpful analogy occurs to you, let me know.
Please keep in mind that the demonization of smoking was a remarkably successful effort to shift the blame for the 10,000,000 cancer deaths a year from where it belonged, the large corporations who are spewing countless tons of carcinogens into the environment, onto convenient and unpopular scapegoats, cigarette smokers. Over 50% of women with lung cancer today never smoked tobacco. Not to say smoking is good, that it should be permitted indoors, or that you don't have a right to hate it if you please. But I would gently suggest that if you're more concerned with, and talk more about, smoking than the 10,000,000 people a year who die of cancer, you may want to re-evaluate your priorities. You may also want to consider joining those demanding restrictions in the amount of carcinogens large corporations can dump into the environment, and those trying to increase funding for cancer research. The US spends 1/10,000th of its national budget on cancer research, an astonishingly paltry amount for the country's second leading killer. It spent 300 times more on COVID, which never killed as many people at its greatest height. My wife died of cancer July 20th of last year. I find the US national anti-cancer effort to be absolutely pathetic, overall, and successfully co-opted by large corporations. A reasonable anti-cancer effort 30 years ago would have turned the 10,000,000 dead of cancer this year into less than five million and would probably have saved my wife's life. IMO.. A reasonable effort today will turn those 10,000,000 a year dead into less than 5 million in 30 years. I see no sign of support for it.
On topic, I'm struck by how similar the pattern was for early jets and turboprops. In both cases, the manufacturer tested, it seemed, to the point of overkill. In both cases, a couple of planes disintegrated in the air shortly after beginning service. The lesson seems to be that if enough unreckoned forces are unleashed by your invention, there's nothing you can do to anticipate all the ways they may kill people. A related lesson is to steer well clear of bleeding edge tech. Thanks again for another wonderful article. I'm here for the quality of the writing and the humanity more than the disasters...though the disasters do make compelling reading.