The DeHaviland Comet: The First Passenger Jet

[@megaprojects9649]

Check out Squarespace: squarespace.com/MEGAPROJECTS for 10% off on your first purchase.

[@kommandantgalileo]

Fun or not so fun fact the comet can be very deadly Also do a megaproject on the B-29

[@mustafaemad3614]

Please make a video about Bar Lev Line, costing around $300 million in 1973.

[@flyingwolffilms]

Do something else besides a plane man I would really appreciate that

[@MrCodwaw101]

Simon, I love your videos. Keep up the hard work, and Happy Thanksgiving to you and your family!

[@vibingwithvinyl]

You may want to correct the title, it's supposed to be "de Havilland Comet."

[@carinamchugh4436]

Dear Simon, make an Aviation channel. We will watch and love it just as much as we loved ALL The variety that used to be on this channel. ☺️

[@starsoffyre]

Agreed. Simon has too few channels!

[@johnconnor2572]

@@starsoffyre Hes clearly been slacking

[@chacecrowell]

Planeographies? Skyprojects?

[@JDHJDH1]

@@chacecrowell planeographics

[@danielchong5032]

Aerographics

[@lairdbufflehead]

My favorite plane. I used to fly on the Dan Air Comet 4C's to Mallorca from Glasgow when I was a kid. The pilots would invite kids including myself to go up and see the cockpit. On one flight the captain asked me to turn the OBS to the new heading for the autopilot in flight. Shame kids can’t experience this any more. This was what started my love for aviation and eventually becoming a pilot myself.

[@JWINDSOR]

Im pretty sure the investigation into the crash basically set the template for all air crash investigation teams that followed. Incredibly beautiful aircraft tho.

[@sandervanderkammen9230]

Unfortunately the only thing learned from the Comet Disaster was that aircraft manufacturers could no longer be trusted to conduct their own crash investigations. The Comet remains the worst jet airliner in history

[@Paul-Nicer58]

Chow Mein gobblers should be aware. *_Accident losses - % of aircraft built._* DeHavilland Comet 4 UK 14% DeHavilland Comet all mks 17% Vickers VC10 UK 5% Boeing 707 USA *20%* Lockheed Electra USA *29%*

[@stephenjenkins10]

I flew to Italy, with Dan-Air, on a Comet4b for a ski holiday back in the late 1970’s. It was supposed to be a direct flight from Belfast, but we actually landed in at London (Gatwick I think) to change planes, to another Comet4b. I believe that these were the last Comet4b’s in commercial service, and on the return flight I took one of the ‘No Smoking’ stickers off the overhead luggage bins. This was stuck on my bedroom door for years, until I moved out and went to University; kind of a souvenir of the last of the Comets.

[@surferdude4487]

I got to see one of these fly once at the CNE Air Show in Toronto.

[@the_hope_of_balarat1109]

Megaproject video suggestion: the US Interstate system. Talk about a *mega* project...

[@sanderschuringa1]

German Autobahn!

[@joshuaosborn]

*Eisenhower Interstate System

[@london651]

I'm with this would love to see this Simon

[@JoaoPessoa86]

If an entire city in the middle of nowhere was only a side project I don't think the interstate would qualify anymore

[@PunksloveTrumpys]

Absolutely. If the Interstate interests you, check out the documentary 'Divided Highways' (1997), and the book it was based off.

[@linkizlinkizzon8427]

Please do JAS 39 Gripen the largest project in Sweden's industrial history! Interesting and revolutionary, and paved the way for all modern fighter jets we see today

[@jonjohnson2844]

I've watched a number of documentaries about the Comet over the years and this is probably the most detailed analysis I've heard, actually learnt a lot of things I hadn't heard before - I'm surprised you never mentioned the change from rectangular to oval windows though, this has always been the central flaw/solution in everything else I've read or seen.

[@MTTT1234]

The thing with the Comet was that aparently the first prototypes had a stronger hull because of the extensive pressurizing and depressurizing tests, which changed the molecular makeup of the alloy, making it more stronger. A feature that the serial models lacked, and which confused the developers of the aircraft when the hull material started to fail much earlier than expected.

[@ignitionfrn2223]

2:05 - Chapter 1 - Looking ahead 4:05 - Chapter 2 - Testing 5:20 - Mid roll ads 7:00 - Chapter 3 - Design 8:55 - Chapter 4 - Maiden flight 10:25 - Chapter 5 - Early problems 11:10 - Chapter 6 - Disaster 12:55 - Chapter 7 - Investigation 14:00 - Chapter 8 - The return 15:30 - Chapter 9 - Legacy - Chapter 10 -

[@BytebroUK]

I think I'm right in saying that even after it was out of commercial service, it continued with the military as the Nimrod.

[@wrightmf]

Reminds me of another commercial airliner that had problems was the Lockheed Electra. However, it went on serving the Navy as a P3 subchaser for decades.

[@thecotswoldflyer]

Correct. In fact the engines being located in the wing roots made it very well suited to sub hunting as you didn't have engines hanging below the wings upsetting the various sensors.

[@sandervanderkammen9230]

No, the Hawker Siddley HS.801 Nimrod is not a Comet, it has a completely different type certification and shares nothing in common with the early failed airliner design.

[@BytebroUK]

@@sandervanderkammen9230 I learn. Thank you.

[@Paul-Nicer58]

Chow Mein gobblers should be aware. Nimrod work started before 1954 at Dehavilland. The Dehavilland team, wherever they were, were responsible for all Nimrod work. The Nimrod is a Comet. *_Accident losses - % of aircraft built._* DeHavilland Comet 4 UK 14% DeHavilland Comet all mks 17% Vickers VC10 UK 5% Boeing 707 USA *20%* Lockheed Electra USA *29%*

[@joshuahudson5336]

Here is a megaproject. The USS Monitor. She may not have been huge, but the impact on naval warfare was massive. She ended wooden sailing warships and warships with rows of guns, had more than 40 patentable components, and the world's first rotating turret ever to be used in battle. She is the true ancestor to all modern warships.

[@garfieldsmith332]

The main outcome from The Battle oh Ha[ton Roads was that is a few short hours all the world's navies became obsolete. And had the Monitor fired full shot rounds the C.S.S. Virginia would have probably been sent to the bottom.

[@joshuahudson5336]

@@garfieldsmith332 That and the fact that the Monitor had so many technological advances that were quickly adopted. Below water marine heads, mechanical ventilation, mechanically rotating turret, just to name a few.

[@garfieldsmith332]

@@joshuahudson5336 Yep. And it gave is name to a whole class of ships. A lot of designs were called "Monitors" after that. "Tough little ship".

[@markleyg]

Always loved the look of the encased engines.

[@kdarkwynde]

Looks cool as hell. Makes maintenance a real bear, though.

[@sandervanderkammen9230]

A major fatal design flaw... which is why no other manufacturers use this design

[@Paul-Nicer58]

Chow Mein gobblers should be aware. *_Accident losses - % of aircraft built._* DeHavilland Comet 4 UK 14% DeHavilland Comet all mks 17% Vickers VC10 UK 5% Boeing 707 USA *20%* Lockheed Electra USA *29%*

[@missinglincoln]

You could have mentioned that the shape of the windows - both passenger and antenna - played a significant role in the stress fractures that led to the mid-air disintegration events. Square windows were the way aeroplane windows had always been...but those were slower, unpressurized craft. Square corners are stress concentrators, and when the fuselage bent and twisted and expanded and contracted, fissures formed in the corners. I believe the results of the wreckage re-build revealed it was the small square window in the top of the fuselage where the antenna (surrounded by an insulating plastic insert) was located was where the failure began in that case. You are very correct when you say that this investigation ultimately saved the lives of countless passengers and crews. Because this was going to happen to *some* aeroplane...and sadly the Comet was first out of the starting gate. Way too many people did die...but at least some good came from their loss, in the end. Beautiful aeroplane. Then, now, always.

[@fe3bal]

I was hoping you could have an Epilogue, where the Comet was heavily modified in the 60's by Hawker Siddeley to make the Nimrod. The first two prototype Nimrods were built from two final unfinished Comet 4C airframes.

[@iainsword6027]

I love the nimrod, one of my favourite aircraft.

[@tomhemming9236]

Nice to see this comment, it was one of my Great-grandfather's projects, he became chairman of Hawker Siddeley having worked at deHavilland before the merger!

[@sandervanderkammen9230]

The Hawker Siddley HS.801 Nimrod is not a Comet, it has a completely different type certification and shares nothing in common with the early failed airliner design.

[@sandervanderkammen9230]

​@@johnhiggins9484*Hey Johnny boy!* *Please name a single British company that still makes commercial jet aircraft in the UK?*

[@petemaly8950]

​@@sandervanderkammen9230 ​@sandervanderkammen9230 We feel we can clear up some misunderztandungz. It's always very important to note the relevant facts obviously. *_Muncherz Krappenz DiktorBummer KARZEESTAN Jurkzxoffenzstadt Aonelynewasz & co - they should all note with much awe and great wonder._* ***** *How come they can't answer simple questions - why is that?* ***** *_DID SOMEBODY ACTUALLY SAY SOMEWHERE THAT THERE'S AIRLINER ASSEMBLY LINES OR SIMILAR IN THE UK OR IRELAND OR THAT Airbus or BOW-WING is actually British? (B-47 wings on many occasions folded up in flight or dropped off while parked)._* Of course Brazil makes very good airliners & Brazil is 100th down list along with Indonesia for wealth per capita. *Norway Holland Denmark Ireland Belgium - Top 20 wealth per capita - Don't make airliners - its as simple as that.* BAe Systems & RR combined now do more Airbus work than Germany on an absolute basis & significantly more work than that on a per capita basis. Per capita for the home nation BAe Systems is the world's largest defence contractor. _BAe systems announced the recent £4 Billion takeover of Colorado based US based Ball Aerospace._ *BAE systems now does a significantly higher value of work for Airbus than it did when it was a major Airbus shareholder before 2005.* *_RR now owns US Engine maker Allison for example which does classified Aerospace work for the US Govt._* The UK has more important stuff to do these days. _Routine simple passenger aircraft airframe assembly is becoming more of a 3rd world / trailer park area thing._ EG - *_The DH Comet - world's first high altitude capable pressurised passenger cabin jet airliner in regular service, world's first jet airliner aircraft to cross the Atlantic, worlds first jet airliner aircraft to complete a global circumnavigation flight series._* *They might try to sensibly answer this question - why do they believe that BAE Systems & RR (aero engines etc) & other companies, for example should be doing anything other than what they currently do & where do they get the idea from that the DH Comet had any affect at all on the progression UK aerospace sector.* *Anybody currently flying on a widebody airliner stands a good chance of being on an aircraft powered by RR gas turbine aero engines built in England.* 📯📯📯📯 *The New RR Trent Ultrafan* *Built In England* *_World's Largest (see T&Cs)_* *_Gas Turbine Aero Engine_* 📯📯📯📯 👍Manufactured by the people on a small island with less than 1% of the world's population.👍 *_A typical but small glimpse of what goes on in the very internationally orientated British aerospace sector._* - Boeing Apache Attack Helicopter. AH-64: *75 UK suppliers,* 7% UK content, global fleet of 1280+ aircraft. *F35B more than 130 UK Suppliers, more than 30% UK content.* *_F35A & F35C more than 130 UK Suppliers, more than 15% UK content._* They might like to answer these questions. *Which airline has just ordered* *60 RR England Trent XWB Engines* *& What aircraft are the engines for?* _Bonus question for 10 extra points._ Which country has the *World's Highest Combined Per Capita* *Nuclear / Defence / Aerospace Sector Activity?* 👍 & 🙂 & of course 😎 indeed. *C H E E R S.* _Toodle_ -PIP- *Old* *_C H A P._* The next line is blank intentionally. The Cue Code below doesn't work. .ci c.viix. .cvi.. vc v..v.iicvx. .. cci. .cci viv. .x.. x.i..x x.ic.c.c V. ​​​​​@

[@LRBerry]

I flew on a Dan-Air Comet from Manchester to Malaga. One of my favourite aircraft. During my time in the Air Training Corps, I and a couple of friends had a guided tour of an RAF Nimrod, outside and inside, which was an amazing experience.

[@DoktorBayerischeMotorenWerke]

You are very lucky to be alive... the Comet has the highest loss rate and fatalities statistics of any jet airliner in history..

[@MrPizzaman09]

Are you an engineer in the 40's/50's and designed something this big + made it? Yes, anything like this is a seriously large project.

[@spir0sgi]

I found your channel about a month ago. I really enjoy your videos and your way of narrating them. Brief yet thorough with a nice personal twist! Keep it up mate!

[@bimblinghill]

If the old adage "if it looks right, it flies right" had truly held it would've been a triumph, because it's a damn sexy looking aircraft. Those engines in the wing roots, the shape of the nose.. just gorgeous.

[@wrightmf]

Yes they do give a sleek look, however, that prevents the Comet from being able to accept high bypass engines unlike the underwing engine design of the 707. But I think it was really big news when this thing first flew twice as fast and much higher than the prop jobs. Probably the next time that happened was the Concorde.

[@bimblinghill]

@@wrightmf Yes it's always a risk to integrate things. Elegance isn't always the most important virtue. Accommodating ever wider engines remains a problem to this day; it was the start of the chain of events that got the 737-max into trouble.

[@anarchyantz1564]

Megaproject Suggestion. Longest deep bore ice core in Antarctica. Took years, loads of drama with it and they found some cool stuff like a fresh water lake under the ice containing previously unknown lifeforms. Would go Well with the other hole projects that are popular Speaking of deep holes, how about the Kidd Mine as well?

[@Gazmus]

This sounded like a cool thing...so I searched to see if anyone had done it. Turns out this channel did it 4 days ago :D I wonder if he saw this comment.

[@anarchyantz1564]

@@Gazmus Well I did spam this comment ever single episode, so 3 times a week for about 4 months so quite likely. He has a team of writers go through the comments and given how many topics and the filming time it usually takes about that long from your suggestion I guess, plus depends on how many thumbs up you get.

[@chadvough8359]

We studied the the Comet in my aircraft systems class. I noticed the photo of the aircraft when Simon mentioned testing, you see the aircraft with a giant structure built around the fuselage.. This photo is actually a photo of testing done after the crashes. They had built a giant water tank then submerge the aircraft over and over to simulate the pressure differential of high altitude flying in cycles. This is how they found the metal fatigue issues with punch riveting, and square windows. An airplane fuselage is a sealed metal tube, When the pressure outside is reduced (When you gain altitude) and inside pressure remains the same the fuselage expands, Then the reverse happens when you descend. Some metals can work harden making them brittle. We learned a lot from the mistakes, making the Comet one of the most important aircraft in aviation history.

[@sandervanderkammen9230]

Boeing, Douglas, Junkers and Lockheed were all manufacturing pressurized passenger airliners prior to the Comet Disaster... What we learned was that DeHaviland was a poorly managed company that was decades behind in aircraft design and construction technology.

[@sandervanderkammen9230]

The Comet Disaster is the worst engineering failure in aviation history...its and example of what happens when a company tries to save weight and cost at the expense of safety... it's called criminal negligence today.

[@Paul-Nicer58]

Chow Mein gobblers should be aware. *_Accident losses - % of aircraft built._* DeHavilland Comet 4 UK 14% DeHavilland Comet all mks 17% Vickers VC10 UK 5% Boeing 707 USA *20%* Lockheed Electra USA *29%*

[@petemaly8950]

​@@sandervanderkammen9230 ​@sandervanderkammen9230 ​@sandervanderkammen9230 ​ Kharzeestan Krappenz DiktorBummer Jurkzxoffenz etc and co - they should all note good with much awestruckness & extreme wonderment. *UPDATE MORE BREAKING NEWS ETC* The fate of De Havilland was due to Govt policy Aerospace sector rationalisation & global economics, it was nothing to do with the Comet. A comprehensive, thorough & protracted testing program was carried out on the prototype & it's assemblies. Of course the Comet did indeed have Ripstop stop provision. De Havilland (Of England) Comets were not grounded after 1970 due to structural problems. *_It's interesting that some of the aircraft on the list should really have been noticeably safer than the Comet due to being a similar type but of much later design & manufacture but they definately were not safer._* How things were back then - *_Accident losses - % of aircraft built._* DeHavilland Comet 4 UK 14% DeHavilland Comet all mks 17% Vickers VC10 UK 5% *_The DH Comet had better safety than or similar safety to many other commercial passenger aircraft of a similar era_* Douglas DC-1 99% Douglas DC-2 47% Douglas DC-3 30% Douglas DC-4 26% Boeing s300 72% Boeing 307 70% Boeing 247 48% Boeing 707 20% Lockheed L-049/149 Constellation 30% Lockheed Electra Turboprop 29% Fairchild FH-227 30% McDonnell Douglas DC-8 14% Sud Aviation Caravelle 15% Canadair CL-44 Turboprop 46% Convair CV-580 Turboprop 22% A comparison of more recent aircraft. Accident losses comparison examples. 1970s - 1980s % of total Aircraft built Similar aircraft type, date / decade, useage, size. Biz Jets BAe-125-800 1.7 % Beechcraft Beechjet 400 2.2 % Cessna 550 Citation II 7.1 % Learjet 35 / 36 12 % Beechcraft 1900 6% Dassault Falcon 10 11.5% Aérospatiale SN.601 22.5% Medium size jets / Turboprops. BAe-146 5.1% Fokker 100 6% McDonnell Douglas DC-9-30 9.5% Fairchild FH-227 30% McDonnell Douglas DC-8 14% Canadair CL-44 Turboprop 46% Convair CV-580 Turboprop 22% Beechcraft, Fokker, McDonnell Douglass, Learjet, Fairchild, Aerospatiale, Canadair, Convair companies defunct. All Comets, including some Comet 1s, had full civilian use certification at some point after 1954, civilian use certification only being withdrawn after commercial flying stopped. Examples were flying until 1997 - one example did a signals research global circumnavigation flight series in 1993 via Australia virtually without a rest travelling 28000 miles, only had an ice warning indicator issue during the flights. *The DH Comet - World Firsts.* 1st gas turbine jet powered airliner. 1st high altitude 8psi pressurised full fuselage length passenger cabin airliner, not a trivial feature as structure strength required for pressurisation considerably exceeded strength required for normal flying stress. Nobody else had done anything similar before the Comet. The b-47 used 2 relatively small, heavily built pressurised modules (the aircraft where 6 had their wings fold up in 2 months while flying & some had their wings fall off while parked). The 1937 Boeing piston engined airliner pressurised passenger cabin was pressurised to 2 psi only - in fact that could easily be done as the normal unpressurized fuselage cabin structure strength for flying stresses only was all that was needed to be adequate so no significant weight increase issues needed addressing. 1st all hydraulically powered flying surface controls & actuators airliner with under carriage wheel disk brakes + ABS. 1st jet airliner to cross the Atlantic. 1st jet aircraft to do a world circumnavigation flights series. *Of course De Havilland had prior experience building many all metal construction airframe aircraft including thousands of jet powered fighter aircraft that were primarily of metal construction with pressurised cockpits & jet engines built by De-Havilland & we know the world's first all metal construction airframe airliner was built in England in the 1920s by Handley Page.* *_De Havilland did indeed always work to better than industry standards at the time, used up to date knowledge for the design & no evidence of negligence or criminal negligence was ever produced in relation to the DH Comet._* The course of De Havilland & the general UK aerospace industry sector was not affected even slightly by the DH Comet. The course of national aerospace sectors obviously being similar & inevitable in many countries. *_Other interesting World firsts_* _World's first turboprop aircraft._ *Vickers Viscount Turboprop Airliner 1947.* *A 1945 Gloster Meteor Aircraft with Turboprop Gas Turbine Engine.* They might like to answer these questions. *Which airline has just ordered* *60 RR England Trent XWB Engines* *& What aircraft are the engines for?* _Bonus question for 10 points._ Which country has the *World's Highest Combined Per Capita* *Nuclear + Defence + Aerospace Sector Activity?* 👍 & 🙂 & of course 😎 indeed. *C H E E R S* & without doubt - _Toodle_ -PIP- *Old* *_C H A P._* . ... . .... . ... ... . ... .. ... .... ... ..... . Ivcxivcxivcxcvc xcxiivxccxvcvccv vivcxiccvccvxxcc

[@s2meister]

Hummm no mention of the Hawker Siddeley Nimrod?

[@NorthernWinterRacing]

How about a video on the Williams Fw14b. Built in 1992 and still regarded as one of the most technologically advanced cars ever built. Great work Simon keep up the great content

[@paulybassman7311]

Simon and Oliver ! You both failed to mention the RAF Nimrod!!!? ALEGENDLY!!

[@roriquevernonii8439]

I started this video expecting a mention, and totally forgot until I saw this.

[@Markle2k]

The Nimrod is not related.

[@roriquevernonii8439]

@@Markle2k I thought the Nimrod was based on the Comet. Where does the Nimrod come from?

[@tristan4777]

The Nimrod was developed from the de Havilland Comet by Hawker Siddeley. The modification of the de Havilland Comet design was extensive. So while they are related, perhaps not closely enough for a mention and possibly not relevant to the history of cvilian aviation.

[@roriquevernonii8439]

I guess it means more to "geeks" who already know, not necessarily his full audience.

[@alistairjohnson8185]

I flew on a Comet 4 in 1970. It was a beautiful, steady plane and a joy to fly in.

[@prmeth3utempet339]

Megaproject suggestion: SS Normandie one of the largest transatlantic liner built as well as the largest turbo electric powered ship ever built and a former blue riband holder

[@TTTzzzz]

I propose a documentary about one of the largest man made systems of the world. The total Dutch water management system. From the smallest ditches to the Delta Works. Through out the country water levels are controlled within 1 cm. Weirs adjust their height sometimes every 10 minutes. The length of Dutch waterways are: Large rivers: 650 km Canals: 6.500 km Small rivers and brooks: 6.200 km Ditches (mostly not monitored): 330.000 km Total: 343.350 km! That is nearly 11 times the circumference of the earth. Monitored waterways are13.350 km in length. That is 0.33 times the circumference of the earth. The Delta Works are the most visible aspects of Dutch water management. But what happens inland is no less impressive. I enjoy your work, Regards, Peter Tholen.

[@tenaciousrodent6251]

Still hoping for Turbinia: The first geekgasm in history.

[@jdreyes3745]

The ship which humiliated the Royal Navy gunboats trying to chase it, being the first steam turbine-powered seagoing vessel.

[@thedevilinthecircuit1414]

Lindybeige has a really good documentary on that: kzbin.info/www/bejne/rKO9Znx7YpZ6gJY

[@arnepianocanada]

Megaproject: figuring out the principle of flight in the first decade or so after the 1903 Wright Brothers' pioneering work. Some of the odd-shaped, monstrous or otherwise ungainly craft look incredible now - but each stepped us along the path to 747s and Space Shuttles.

[@Fish-kz8xw]

Megaproject suggestion: Fort Drum aka the concrete battleship.

[@delurkor]

I flew on a Comet in 1959 (age 14) from Le Havre to Heathrow(?). I remembered news report from the early '50s and was somewhat nervous. We made it with no incident. We returned later via train and ferry. I was disappointed; our passenger car did not have individual doors in the compartments like all movies with English trains.

[@sandervanderkammen9230]

You flew on the completely new, redesigned Comet 4. All the Comet 1 aircraft had their airworthiness certification permanently revoked, they never carried commercial passenger in regular service after 1954 and were eventually all scrapped or used in testing.

[@petemaly8950]

​@@sandervanderkammen9230 ​ ​ Kharzeestan Krappenz DiktorBummer Jurkzxoffenz etc and co - they should all note good with much awestruckness & extreme wonderment. *UPDATE MORE BREAKING NEWS ETC* The fate of De Havilland was due to Govt policy Aerospace sector rationalisation & global economics, it was nothing to do with the Comet. A comprehensive, thorough & protracted testing program was carried out on the prototype & it's assemblies. Of course the Comet did indeed have Ripstop stop provision. De Havilland (Of England) Comets were not grounded after 1970 due to structural problems. *_It's interesting that some of the aircraft on the list should really have been noticeably safer than the Comet due to being a similar type but of much later design & manufacture but they definately were not safer._* How things were back then - *_Accident losses - % of aircraft built._* DeHavilland Comet 4 UK 14% DeHavilland Comet all mks 17% Vickers VC10 UK 5% *_The DH Comet had better safety than or similar safety to many other commercial passenger aircraft of a similar era_* Douglas DC-1 99% Douglas DC-2 47% Douglas DC-3 30% Douglas DC-4 26% Boeing s300 72% Boeing 307 70% Boeing 247 48% Boeing 707 20% Lockheed L-049/149 Constellation 30% Lockheed Electra Turboprop 29% Fairchild FH-227 30% McDonnell Douglas DC-8 14% Sud Aviation Caravelle 15% Canadair CL-44 Turboprop 46% Convair CV-580 Turboprop 22% A comparison of more recent aircraft. Accident losses comparison examples. 1970s - 1980s % of total Aircraft built Similar aircraft type, date / decade, useage, size. Biz Jets BAe-125-800 1.7 % Beechcraft Beechjet 400 2.2 % Cessna 550 Citation II 7.1 % Learjet 35 / 36 12 % Beechcraft 1900 6% Dassault Falcon 10 11.5% Aérospatiale SN.601 22.5% Medium size jets / Turboprops. BAe-146 5.1% Fokker 100 6% McDonnell Douglas DC-9-30 9.5% Fairchild FH-227 30% McDonnell Douglas DC-8 14% Canadair CL-44 Turboprop 46% Convair CV-580 Turboprop 22% Beechcraft, Fokker, McDonnell Douglass, Learjet, Fairchild, Aerospatiale, Canadair, Convair companies defunct. All Comets, including some Comet 1s, had full civilian use certification at some point after 1954, civilian use certification only being withdrawn after commercial flying stopped. Examples were flying until 1997 - one example did a signals research global circumnavigation flight series in 1993 via Australia virtually without a rest travelling 28000 miles, only had an ice warning indicator issue during the flights. *The DH Comet - World Firsts.* 1st gas turbine jet powered airliner. 1st high altitude 8psi pressurised full fuselage length passenger cabin airliner, not a trivial feature as structure strength required for pressurisation considerably exceeded strength required for normal flying stress. Nobody else had done anything similar before the Comet. The b-47 used 2 relatively small, heavily built pressurised modules (the aircraft where 6 had their wings fold up in 2 months while flying & some had their wings fall off while parked). The 1937 Boeing piston engined airliner pressurised passenger cabin was pressurised to 2 psi only - in fact that could easily be done as the normal unpressurized fuselage cabin structure strength for flying stresses only was all that was needed to be adequate so no significant weight increase issues needed addressing. 1st all hydraulically powered flying surface controls & actuators airliner with under carriage wheel disk brakes + ABS. 1st jet airliner to cross the Atlantic. 1st jet aircraft to do a world circumnavigation flights series. *Of course De Havilland had prior experience building many all metal construction airframe aircraft including thousands of jet powered fighter aircraft that were primarily of metal construction with pressurised cockpits & jet engines built by De-Havilland & we know the world's first all metal construction airframe airliner was built in England in the 1920s by Handley Page.* *_De Havilland did indeed always work to better than industry standards at the time, used up to date knowledge for the design & no evidence of negligence or criminal negligence was ever produced in relation to the DH Comet._* The course of De Havilland & the general UK aerospace industry sector was not affected even slightly by the DH Comet. The course of national aerospace sectors obviously being similar & inevitable in many countries. *_Other interesting World firsts_* _World's first turboprop aircraft._ *Vickers Viscount Turboprop Airliner 1947.* *A 1945 Gloster Meteor Aircraft with Turboprop Gas Turbine Engine.* They might like to answer these questions. *Which airline has just ordered* *60 RR England Trent XWB Engines* *& What aircraft are the engines for?* _Bonus question for 10 points._ Which country has the *World's Highest Combined Per Capita* *Nuclear + Defence + Aerospace Sector Activity?* 👍 & 🙂 & of course 😎 indeed. *C H E E R S* & without doubt - _Toodle_ -PIP- *Old* *_C H A P._* . .... .. .. ... .... ... ..... . Ivcxivcxivcx xcxiivxvccv vivcxiccxxcc

[@mikesullivanteexpat8712]

Had heard of the DeHaviland Comet but never new the detail, interesting look into its beginnings and eventual demise.

[@JeffDeWitt]

In something like 1966 I went on my first plane trip by myself. My parents put me on a plane in Chicago and my grandparents picked me up at Newark. On the way I rode in a 707 (I know because it said "Boeing 707" on the window frame), on the way back I rode in a Comet. It was so long ago that my meal including a free small pack of Winston cigarettes'... they gave cigarettes to a 10 year old kid on an airplane!

[@ebola1974]

Fun fact: Saving Private Ryan and Band of Brothers were filmed at the old De Havilland aerodrome in Hatfield, England

[@MrDragon1968]

Indeed. I was on the set for a couple of days. It was fun walking around the 'towns' they'd constructed.

[@eileenobyrne-hudson8636]

No materials science textbook is complete without a mention of the Comet in the fracture mechanics section. But as stated, it was a good lesson for the rest of the industry. A lot of engineering is about looking at what others have already done, and understanding why they chose the path they did. No sense is repeating others' mistakes. Or wasting time doing work that's already been done.

[@mochaholic3039]

Another thing that played against the Comet: the engines, they were deeply buried within the wing-roots. Those were a pain in the butt to work on, especially when engine removal was necessary to do maintenance. That's one of the reasons Boeings and etc with underwing mounted engines won the market, those easily accessible engines made mechanics' lives much more easier and enabled much speedier turnaround times.

[@sandervanderkammen9230]

At least 3 crashed due to the placement of the engines, the Comet 4 required major corrections to fix this fatal flaw in the Comets original design.

[@petemaly8950]

​@@sandervanderkammen9230 ​ Kharzeestan Krappenz DiktorBummer Jurkzxoffenz etc and co - they should all note good with much awestruckness & extreme wonderment. *UPDATE MORE BREAKING NEWS ETC* The fate of De Havilland was due to Govt policy Aerospace sector rationalisation & global economics, it was nothing to do with the Comet. A comprehensive, thorough & protracted testing program was carried out on the prototype & it's assemblies. Of course the Comet did indeed have Ripstop stop provision. De Havilland (Of England) Comets were not grounded after 1970 due to structural problems. The engine position was not a flaw & caused no crashes. *_It's interesting that some of the aircraft on the list should really have been noticeably safer than the Comet due to being a similar type but of much later design & manufacture but they definately were not safer._* How things were back then - *_Accident losses - % of aircraft built._* DeHavilland Comet 4 UK 14% DeHavilland Comet all mks 17% Vickers VC10 UK 5% *_The DH Comet had better safety than or similar safety to many other commercial passenger aircraft of a similar era_* Douglas DC-1 99% Douglas DC-2 47% Douglas DC-3 30% Douglas DC-4 26% Boeing s300 72% Boeing 307 70% Boeing 247 48% Boeing 707 20% Lockheed L-049/149 Constellation 30% Lockheed Electra Turboprop 29% Fairchild FH-227 30% McDonnell Douglas DC-8 14% Sud Aviation Caravelle 15% Canadair CL-44 Turboprop 46% Convair CV-580 Turboprop 22% A comparison of more recent aircraft. Accident losses comparison examples. 1970s - 1980s % of total Aircraft built Similar aircraft type, date / decade, useage, size. Biz Jets BAe-125-800 1.7 % Beechcraft Beechjet 400 2.2 % Cessna 550 Citation II 7.1 % Learjet 35 / 36 12 % Beechcraft 1900 6% Dassault Falcon 10 11.5% Aérospatiale SN.601 22.5% Medium size jets / Turboprops. BAe-146 5.1% Fokker 100 6% McDonnell Douglas DC-9-30 9.5% Fairchild FH-227 30% McDonnell Douglas DC-8 14% Canadair CL-44 Turboprop 46% Convair CV-580 Turboprop 22% Beechcraft, Fokker, McDonnell Douglass, Learjet, Fairchild, Aerospatiale, Canadair, Convair companies defunct. All Comets, including some Comet 1s, had full civilian use certification at some point after 1954, civilian use certification only being withdrawn after commercial flying stopped. Examples were flying until 1997 - one example did a signals research global circumnavigation flight series in 1993 via Australia virtually without a rest travelling 28000 miles, only had an ice warning indicator issue during the flights. *The DH Comet - World Firsts.* 1st gas turbine jet powered airliner. 1st high altitude 8psi pressurised full fuselage length passenger cabin airliner, not a trivial feature as structure strength required for pressurisation considerably exceeded strength required for normal flying stress. Nobody else had done anything similar before the Comet. The b-47 used 2 relatively small, heavily built pressurised modules (the aircraft where 6 had their wings fold up in 2 months while flying & some had their wings fall off while parked). The 1937 Boeing piston engined airliner pressurised passenger cabin was pressurised to 2 psi only - in fact that could easily be done as the normal unpressurized fuselage cabin structure strength for flying stresses only was all that was needed to be adequate so no significant weight increase issues needed addressing. 1st all hydraulically powered flying surface controls & actuators airliner with under carriage wheel disk brakes + ABS. 1st jet airliner to cross the Atlantic. 1st jet aircraft to do a world circumnavigation flights series. *Of course De Havilland had prior experience building many all metal construction airframe aircraft including thousands of jet powered fighter aircraft that were primarily of metal construction with pressurised cockpits & jet engines built by De-Havilland & we know the world's first all metal construction airframe airliner was built in England in the 1920s by Handley Page.* *_De Havilland did indeed always work to better than industry standards at the time, used up to date knowledge for the design & no evidence of negligence or criminal negligence was ever produced in relation to the DH Comet._* The course of De Havilland & the general UK aerospace industry sector was not affected even slightly by the DH Comet. The course of national aerospace sectors obviously being similar & inevitable in many countries. *_Other interesting World firsts_* _World's first turboprop aircraft._ *Vickers Viscount Turboprop Airliner 1947.* *A 1945 Gloster Meteor Aircraft with Turboprop Gas Turbine Engine.* They might like to answer these questions. *Which airline has just ordered* *60 RR England Trent XWB Engines* *& What aircraft are the engines for?* _Bonus question for 10 points._ Which country has the *World's Highest Combined Per Capita* *Nuclear + Defence + Aerospace Sector Activity?* 👍 & 🙂 & of course 😎 indeed. *C H E E R S* & without doubt - _Toodle_ -PIP- *Old* *_C H A P._* . .... . ... ... .. ... .... ... ..... . Ivcxivcxivcx xcxiivxccxvccv vivcxmcvxxcc

[@kl0wnkiller912]

I read a report years ago that stated that the square windows were not strong enough and they cracked at the corners, causing catastrophic failure. That is why the newer Comets have round windows. One of my earliest memories is of my family taking a flight somewhere and getting on the plane. It was a Boeing 707 and my dad, being a pilot, asked to see the cockpit. We got escorted to the cockpit and the pilot even asked if I wanted to "fly it". I was all of 5 or 6 years old so pretty sure I would have just sat on his lap or something but I declined. The stewardess took us back to our seats and later gave me a little set of gold wing with PAA (Pan America Airlines) on it. Wish I had those today! Times sure have changed.

[@DoktorBayerischeMotorenWerke]

That is a completely false narrative, De Havilland admitted that they never performed the stress calculations for the fuselage sections that failed, BEA certification only required a single section of fuselage to be pressure tested. Subsequent modern investigations confirmed that the Comet was built with aluminum skins that were too thin and brittle, the plane lacked proper rip-stop double joints, and the fuselage support rings were too narrow and spaced too far apart. the quality of the riveted Fastners was also substandard and defective..

[@bob2161]

Hello Simon, another fine Megaprojects episode. As always, I learned something new. You did, however, leave a point, unanswered. You mentioned the two failed takeoffs that were initially ruled as pilot error. You indicated that that ruling was itself, in error. However, you never stated what the actual cause of those accidents were. I'm pretty confident that a pressurization problem would not have been a contributing issue to a failed takeoff. Don't leave us hanging like that. How about a follow up?

[@sandervanderkammen9230]

Excellent comments, the answer is the design of the engines in the wing were ultimately responsible for several major runway excursions. Based on a British aerodynamic theory that later proved completely wrong, wind tunnel tests did not account for angle of attack at take-off. The flawed placement of the engine inlets in the wings leading edge caused a disruption of air flow into the engines causing loss of thrust, AND disrupted flow over the wing causing loss of lift at the critical rotation angle. Comet 4 required extensive modifications to the wings and inlets and take-off performance was reduced to mitigate the effects that could not be fixed. No other manufacturers have ever used this design.

[@bob2161]

@@sandervanderkammen9230 Wow! Thank you. After all this time (2 years) someone has an answer. And your answer completely makes sense to me. Even though the inlet arrangement isn't the issue, modern twin jet airliners have a takeoff procedure in place to avoid the same problem. As the takeoff roll begins, the pilot pushes the throttles to only a partial setting. Then a short time later the throttles are push up all the way to takeoff power. The reason is that at the initial slow speed, if one engines output failed, while the other spun up to full thrust, the pilots would not be able to keep the plane on the runway. Only after they've confirmed that both engines output have reached a certain level (usually 40%) do they apply full power. There are instruments that display this information to the pilots. I do not know if the procedure is 40% for all twin jets, but it will be similar. Thanks again for the answer.

[@sandervanderkammen9230]

@@bob2161 Not exactly, it is an aerodynamic issue, not related to the engines themselves. If you look carefully at the engine inlets on the Comet 1 and compare them to the Comet 4 you will see some significant re-engineering, the 4 has much larger inlets which are angled downwards below leading edge line. They help reduce the problem but do not solve it completely, the new inlets are less efficent and create more drag.

[@sandervanderkammen9230]

@@bob2161 The Comet 4 was also redesigned with improve wings, flaps and hydraulic flight controls to reduce the angle of attack at rotation and prevent pilots from accidententally over-rotating if the plane doesn't lift-off at the proper V-speed. The Comet 4 requires a longer temperature/altitude/GTOW distatance and the new engines provide more thrust to weight ratio performance at TO.

[@bob2161]

@@sandervanderkammen9230 i understood that it wasn't the engines themselves. It was due to the shape of the original inlets. When the angle of attack was wrong, the inlet would restrict the airflow to the engine. This would cause an interruption of power from the engine. If/when this happens on one side of the plane, but not the other, an asymmetrical thrust condition is created. At low airspeeds and/or high angles of attack, there wouldn't be enough control authority to keep the plane from yawing towards the compromised engine. This would indeed cause an "Uncommanded excursion from the desired flight profile". It isn't the same problem I described with the modern twin jets, but it produces the same symptoms, and ultimate outcome.

[@jocelynhurtubise2420]

Very good as always, may I suggested a video on the Canadian Jetliner CF-102 (Made by the same people who built the CF-105) it flew around the same time as the comet.

[@Iamchrome327]

Fun fact: The first passenger jet was nearly the Avro Canada C102 Jetliner, with the Comet beating the Jetliner by 13 days.

[@garfieldsmith332]

Yep. There was a rush by DH to get into the air first. I believe the CF-102 was a superior aircraft. A tad slower but all round better and safer.

[@martinda7446]

@@garfieldsmith332 It was simply NOT even close to the sophistication of the Comet. There simply isn't one part in all the thousands of pieces that approached the genius of the Comet engineering. The Comet was the archetype commercial jetliner and still looks the part 70 years later. The 102 looks like a DC4 with an engine upgrade.

[@caligulapontifex5759]

@@martinda7446 🤔, yeah about that engineering. The poor souls on those three Comets lost within 12 months would disagree with that assessment.

[@johnpinckney4979]

Don't forget the Nene Viking with two R-R Nene engines and Tay Viscount with R-R Tay jets...

[@garfieldsmith332]

@@martinda7446 I do not think the Comet looks that great. Similar engine configuration to the C-102. I would rather fly in a DC-4 with and engine upgrade back then.

[@ninchan2]

speaking of aircrafts taking off from Heathrow... how about a video ON Heathrow? not sure if it qualifies for a mega- or sideproject (geographics?) but the story of the airport from its small beginnings to what it is today is quite interesting and the whole 3rd runway debacle could take up a video on its own.

[@darrelvincent970]

The Arecibo observatory

[@darrelvincent970]

Come on Simon you have to do it Sean Bean died there

[@cynthiasimpson931]

And I'll shut up about it!

[@stringtheorysucks]

Sadly Arecibo will be demolished soon.

[@Viper-dn8ix]

Hey there Simon! Once again I am asking you to check out Denver International Airport! It's the second largest airport in the world, fifth busiest in the USA, and one of the busiest in the world! The airport is massive... Six runways, with an option to expand to more. And the terminal building is probably one of the more beautiful and inspired designs for an airport. Plus it's got some sick sunglasses! Kidding that's just the new hotel! There's also a host of conspiracy theories for you to unpack too!

[@Rammstein0963.]

Beautiful airplane, sad that it took several fatal accidents to figure out the windows were the problem. You'd have thought they'd have figured that out sooner given that WWII aircraft with pressurized airframes like the B-29 already were using rounded windows YEARS earlier.

[@GimbleOnDew]

Material properties weren't nearly as well understood as they are today.

[@bimblinghill]

Kind of. They understood the raw strength benefits of a round window, but ease of manufacturing favoured a square for the Comet. What they didn't appreciate was how much the strength falls off with fatigue.

[@PenzancePete]

The B-29 wasn't a completely pressurised aircraft. By the same token some P.R. Spitfires and Mosquitos were pressurised. Pressurising a complete airframe for 40,000' is a whole different ball game.

[@petemaly8950]

DH were doing all metal airframe construction aircraft & pressurised cabin aircraft & building jet engines for many years before the Comet. They also knew all there was to know about metal fatigue at the time & carried out an extensive & protracted programme of testing & proving before the first Comet prototype flew. They were also fully up to speed in all matters related to pressure vessels & any stress concentrations due to cutouts such as windows doors & hatches. Nobody had done an airliner with an 8 psi pressurised full fuselage length passenger cabin before the Comet.

[@profpocket]

As previous comments have said, Turbinia, (Can't believe how he hasn't done one on that yet) Arecibo Observatory, and the United States Interstate Highway system would be pretty interesting content to talk about.

[@sanderschuringa1]

Haha! “Build an airliner yourself and tell me it’s not!” [a MegaProject] KING COMMENT!

[@sanderschuringa1]

Comment / Comet 😝

[@katokhaelan4881]

Haha yeah that was awesome lol

[@jvillan94]

The Comet 4 in BOAC livery *chefs kiss 👌🏻

[@TailSpinRCSpain]

They used to fly over our school when they were converting them to Nimrods c1971.

[@sandervanderkammen9230]

The Nimrods were new aircraft manufactured by Hawker-Siddeley.

[@TailSpinRCSpain]

@@sandervanderkammen9230 I never knew that, cheers. They also flew the Vulcan, Victor and Shackleton right over the playground on approach to Woodford Aerodrome. We saw many prototype variants of Nimrod with different R.A.D.A.R domes.

[@RJM1011]

@@sandervanderkammen9230 The main body was from the Comet ! I worked at FRA and when the aircraft were striped down you could see where there had changed the windows from the square ones !

[@sandervanderkammen9230]

@@RJM1011 Not true, only the prototype of the Nimrod was built from a unsold Comet 4C. The Comet 4C was a completely redesigned aircraft and none were ever built with square windows. It seems you have your facts confused here.

[@petemaly8950]

​@@sandervanderkammen9230 ​ Kharzeestan Krappenz DiktorBummer Jurkzxoffenz etc and co - they should all note good with much awestruckness & extreme wonderment. *UPDATE MORE BREAKING NEWS ETC* The Comet was designed with military use in mind, prototype Nimrod work started at Dehavilland in 1953. Nearly all changes from the Comet 1 to Comet 4 were simply previously scheduled improvements that had nothing to do with any claimed relevant incidents. The fate of De Havilland was due to Govt policy Aerospace sector rationalisation & global economics, it was nothing to do with the Comet. A comprehensive, thorough & protracted testing program was carried out on the prototype & it's assemblies. Of course the Comet did indeed have Ripstop stop provision. De Havilland (Of England) Comets were not grounded after 1970 due to structural problems. *_It's interesting that some of the aircraft on the list should really have been noticeably safer than the Comet due to being a similar type but of much later design & manufacture but they definately were not safer._* How things were back then - *_Accident losses - % of aircraft built._* DeHavilland Comet 4 UK 14% DeHavilland Comet all mks 17% Vickers VC10 UK 5% *_The DH Comet had better safety than or similar safety to many other commercial passenger aircraft of a similar era_* Douglas DC-1 99% Douglas DC-2 47% Douglas DC-3 30% Douglas DC-4 26% Boeing s300 72% Boeing 307 70% Boeing 247 48% Boeing 707 20% Lockheed L-049/149 Constellation 30% Lockheed Electra Turboprop 29% Fairchild FH-227 30% McDonnell Douglas DC-8 14% Sud Aviation Caravelle 15% Canadair CL-44 Turboprop 46% Convair CV-580 Turboprop 22% A comparison of more recent aircraft. Accident losses comparison examples. 1970s - 1980s % of total Aircraft built Similar aircraft type, date / decade, useage, size. Biz Jets BAe-125-800 1.7 % Beechcraft Beechjet 400 2.2 % Cessna 550 Citation II 7.1 % Learjet 35 / 36 12 % Beechcraft 1900 6% Dassault Falcon 10 11.5% Aérospatiale SN.601 22.5% Medium size jets / Turboprops. BAe-146 5.1% Fokker 100 6% McDonnell Douglas DC-9-30 9.5% Fairchild FH-227 30% McDonnell Douglas DC-8 14% Canadair CL-44 Turboprop 46% Convair CV-580 Turboprop 22% Beechcraft, Fokker, McDonnell Douglass, Learjet, Fairchild, Aerospatiale, Canadair, Convair companies defunct. All Comets, including some Comet 1s, had full civilian use certification at some point after 1954, civilian use certification only being withdrawn after commercial flying stopped. Examples were flying until 1997 - one example did a signals research global circumnavigation flight series in 1993 via Australia virtually without a rest travelling 28000 miles, only had an ice warning indicator issue during the flights. *The DH Comet - World Firsts.* 1st gas turbine jet powered airliner. 1st high altitude 8psi pressurised full fuselage length passenger cabin airliner, not a trivial feature as structure strength required for pressurisation considerably exceeded strength required for normal flying stress. Nobody else had done anything similar before the Comet. The b-47 used 2 relatively small, heavily built pressurised modules (the aircraft where 6 had their wings fold up in 2 months while flying & some had their wings fall off while parked). The 1937 Boeing piston engined airliner pressurised passenger cabin was pressurised to 2 psi only - in fact that could easily be done as the normal unpressurized fuselage cabin structure strength for flying stresses only was all that was needed to be adequate so no significant weight increase issues needed addressing. 1st all hydraulically powered flying surface controls & actuators airliner with under carriage wheel disk brakes + ABS. 1st jet airliner to cross the Atlantic. 1st jet aircraft to do a world circumnavigation flights series. *Of course De Havilland had prior experience building many all metal construction airframe aircraft including thousands of jet powered fighter aircraft that were primarily of metal construction with pressurised cockpits & jet engines built by De-Havilland & we know the world's first all metal construction airframe airliner was built in England in the 1920s by Handley Page.* *_De Havilland did indeed always work to better than industry standards at the time, used up to date knowledge for the design & no evidence of negligence or criminal negligence was ever produced in relation to the DH Comet._* The course of De Havilland & the general UK aerospace industry sector was not affected even slightly by the DH Comet. The course of national aerospace sectors obviously being similar & inevitable in many countries. *_Other interesting World firsts_* _World's first turboprop aircraft._ *Vickers Viscount Turboprop Airliner 1947.* *A 1945 Gloster Meteor Aircraft with Turboprop Gas Turbine Engine.* They might like to answer these questions. *Which airline has just ordered* *60 RR England Trent XWB Engines* *& What aircraft are the engines for?* _Bonus question for 10 points._ Which country has the *World's Highest Combined Per Capita* *Nuclear + Defence + Aerospace Sector Activity?* 👍 & 🙂 & of course 😎 indeed. *C H E E R S* & without doubt - _Toodle_ -PIP- *Old* *_C H A P._* . .... . ... ... . ... .. ... .... ... ..... . Ivcxivcxivcx xcxiivxccxvccv vivcxiccvccvxxcc

[@pauld6967]

With my years of interest in aviation and history I had long been aware of the situation with the Comet but thank you for introducing this to a new set of people that may be learning about this for the first time.

[@D0P1C3]

ThrustSSC first land vehicle to officially break the sound barrier

[@ethannilsson9638]

Simon, my friend. The Sanitary Movement of the 1850's. Likely the biggest public works project ever. Think of London. Imagine retrofitting the entire city with modern sewers.

[@bcfairlie1]

I always loved the styling and look of the Comet.

[@DoktorBayerischeMotorenWerke]

Unfortunately, it was severely flawed and structurally unsound..

[@Christian-nl7cm]

the integrated engines into the wings still looks more futuristic than anything now

[@sandervanderkammen9230]

Tragic engineering blunder, the engine placement was a fatal flaw.

[@petemaly8950]

​@@sandervanderkammen9230 ​​​@sandervanderkammen9230 Kharzeestan Krappenz DiktorBummer Jurkzxoffenz etc and co - they should all note good with much awestruckness & extreme wonderment. *UPDATE MORE BREAKING NEWS ETC* The engine positioning had some advantages & were of course not a flaw of any type. De Havilland (Of England) Comets were not grounded after 1970 due to structural problems. *_It's interesting that some of the aircraft on the list should really have been noticeably safer than the Comet due to being a similar type but of much later design & manufacture but they definately were not safer._* How things were back then - *_Accident losses - % of aircraft built._* DeHavilland Comet 4 UK 14% DeHavilland Comet all mks 17% Vickers VC10 UK 5% *_The DH Comet had better safety than or similar safety to many other commercial passenger aircraft of a similar era_* Douglas DC-1 99% Douglas DC-2 47% Douglas DC-3 30% Douglas DC-4 26% Boeing s300 72% Boeing 307 70% Boeing 247 48% Boeing 707 20% Lockheed L-049/149 Constellation 30% Lockheed Electra Turboprop 29% Fairchild FH-227 30% McDonnell Douglas DC-8 14% Sud Aviation Caravelle 15% Canadair CL-44 Turboprop 46% Convair CV-580 Turboprop 22% A comparison of more recent aircraft. Accident losses comparison examples. 1970s - 1980s % of total Aircraft built Similar aircraft type, date / decade, useage, size. Biz Jets BAe-125-800 1.7 % Beechcraft Beechjet 400 2.2 % Cessna 550 Citation II 7.1 % Learjet 35 / 36 12 % Beechcraft 1900 6% Dassault Falcon 10 11.5% Aérospatiale SN.601 22.5% Medium size jets / Turboprops. BAe-146 5.1% Fokker 100 6% McDonnell Douglas DC-9-30 9.5% Fairchild FH-227 30% McDonnell Douglas DC-8 14% Canadair CL-44 Turboprop 46% Convair CV-580 Turboprop 22% Beechcraft, Fokker, McDonnell Douglass, Learjet, Fairchild, Aerospatiale, Canadair, Convair companies defunct. All Comets, including some Comet 1s, had full civilian use certification at some point after 1954, civilian use certification only being withdrawn after commercial flying stopped. Examples were flying until 1997 - one example did a signals research global circumnavigation flight series in 1993 via Australia virtually without a rest travelling 28000 miles, only had an ice warning indicator issue during the flights. *The DH Comet - World Firsts.* 1st gas turbine jet powered airliner. 1st high altitude 8psi pressurised full fuselage length passenger cabin airliner, not a trivial feature as structure strength required for pressurisation considerably exceeded strength required for normal flying stress. Nobody else had done anything similar before the Comet. The b-47 used 2 relatively small, heavily built pressurised modules (the aircraft where 6 had their wings fold up in 2 months while flying & some had their wings fall off while parked). The 1937 Boeing piston engined airliner pressurised passenger cabin was pressurised to 2 psi only - in fact that could easily be done as the normal unpressurized fuselage cabin structure strength for flying stresses only was all that was needed to be adequate so no significant weight increase issues needed addressing. 1st all hydraulically powered flying surface controls & actuators airliner with under carriage wheel disk brakes + ABS. 1st jet airliner to cross the Atlantic. 1st jet aircraft to do a world circumnavigation flights series. *Of course De Havilland had prior experience building many all metal construction airframe aircraft including thousands of jet powered fighter aircraft that were primarily of metal construction with pressurised cockpits & jet engines built by De-Havilland & we know the world's first all metal construction airframe airliner was built in England in the 1920s by Handley Page.* *_De Havilland did indeed always work to better than industry standards at the time, used up to date knowledge for the design & no evidence of negligence or criminal negligence was ever produced in relation to the DH Comet._* The course of De Havilland & the general UK aerospace industry sector was not affected even slightly by the DH Comet. The course of national aerospace sectors obviously being similar & inevitable in many countries. *_Other interesting World firsts_* _World's first turboprop aircraft._ *Vickers Viscount Turboprop Airliner 1947.* *A 1945 Gloster Meteor Aircraft with Turboprop Gas Turbine Engine.* They might like to answer these questions. *Which airline has just ordered* *60 RR England Trent XWB Engines* *& What aircraft are the engines for?* _Bonus question for 10 points._ Which country has the *World's Highest Combined Per Capita* *Nuclear + Defence + Aerospace Sector Activity?* 👍 & 🙂 & of course 😎 indeed. *C H E E R S* & without doubt - _Toodle_ -PIP- *Old* *_C H A P._* . .... . ... . ... .. ... ... . ... .... Ivcxivcxivcxcx iivxvivcxiccxxcc

[@android584]

Maybe an ease of maintenance flaw.

[@WilhelmKarsten]

​It was a flaw that caused several crashes. ​@@android584

[@mattjames9941]

Should’ve mentioned that the Comet went on to become the Nimrod maritime patrol jet following extensive modifications by Hawker Siddeley. It was a superb aircraft.

[@sandervanderkammen9230]

The Hawker Siddley HS.801 Nimrod is not a Comet, it has a completely different type certification and shares nothing in common with the early failed airliner design.

[@logangaudet540]

Hey Simon, have you ever looked into the confederation bridge in Atlantic Canada? It’s. 12.9 km bridge connecting 2 provinces to each other, constructed in the 90s.

[@Cunoslav]

Soooo... The first engines were Ghosts 'n Goblins...

[@BillHalliwell]

G'day Simon, In this excellent, balanced video you hit the nail right on the head towards the end. Much blame has been put on the Comet Mk1's rectangular windows as being the cause of the crashes. While they were an indicator and were, in a large part, to blame; the other faults included the fuselage skin that was far too thin and made of alloys that were prone to fatigue; the wing struts were, similarly, not as strong as they needed to be and the overall riveting method was found to be detrimental to the structural integrity of the skin in the fuselage and control surfaces. I've always been an aircraft geek and just before I joined the Air Force, many years ago, I was lucky enough to fly on two aircraft that were high on my must-fly list; they were the HS-748 and the Comet. I snagged an, all too brief, flight on a Comet 4 with Dan-Air, an airline with a spotted history of flight safety. I found the Dan-Air Comet 4 to be a little more cramped than I expected, however, it was a comfortable, stable and quiet aircraft if one was above or forward of the wings. It is a memory I'll never forget but one always tinged with sadness. I had already flown on a 707 by then and I had to admit I saw the, obvious, advantages of that aircraft. My 'jolly' on the HS-748 was a good flight but noisy. I could have saved my money, however, as I soon discovered that 748s were flown by the Air Force so, I flew on them, a few times and got paid for it! Imagine if the Comet had never been. Would the Boeing 707 have had the disasters that befell the Comet? Given that 'what if'; no 707, possibly no 747. Apart from making history as the world's first passenger jetliner; it's tragic crashes also, as many believe, made jet passenger airliners much safer the world over. It's rare indeed to find an instance of a quantum leap in aviation technology without some casualties or tragedies. No one talks of the Douglas, Boeing or Lockheed safety incidents much these days, even though some of them involved a large loss of life. Thanks again for a great video. Cheers, BH

[@sandervanderkammen9230]

Boeing, Douglas, Lockheed and Junkers were decades ahead of DeHaviland in pressurized cabins and riveted aluminum airframes... You realize that DeHaviland was still building WOOD biplanes like the Dragon Rapide in the late 1940s... Even the Vampire and Venom were still made of *WOOD!!!!*

[@BillHalliwell]

@@sandervanderkammen9230 G'day Sander, I think there is a slight misunderstanding on your part. I did not denigrate Boeing, Lockheed or Douglas nor was that my intention. The Mk 1 DH Comet being the first of its type and conceived during WW2 was ground-breaking technology 'almost' a decade ahead of its time. Supermarine experimented with flush riveting during the height of the Schneider Trophy's popularity, pre-WW2. Howard Hughes did similar 'flush jobs' on 2 of his racing planes, yes, pre-WW2. The Mk 1 Comet's main flaw was using, basically, conventional metal skin technology in an aircraft never before put under the stresses of continual cycles and their concomitant vibration issues brought about by the jet technology of the time. It's demonstrable and a fact that many British aeronautical and other technical innovations were passed on to the US (gratis) because Churchill, even before he was PM and at the Admiralty, was willing to go to any lengths to draw the US into WW2. This process began before the war, like British proximity fuse technology. There's no room here to go into the long list, however, when it came to British jet technology the Brits keenly handed over all they had on Sir Frank Whittle's jet engine inventions. The US military then 'gladly' invited British scientists and technologists to the US. By the time various British teams arrived in the US to work on different projects; the same military leaders made certain that laws were passed that forbade them from sharing any of 'their' military technology, even with Allies. The Brits were told, quite clearly to go home. This happened again when a certain team of British scientists, instrumental in new atomic fission theories were also told to go home even though they had been officially invited. True, some Brits did work on the Manhattan project but only at the insistence of Prof. Oppenheimer. Back to jets. It is also demonstrable that the early US attempts of replicating the successes of the British Gloster Meteor or the ME-262 were pitiful; their prototypes were slow, had low ceilings, poor ranges and handling. The notorious US Operation Paperclip didn't exclusively poach German rocket scientists but also jet propulsion experts, among other disciplines. Finally, with respect, you seem fixated on aircraft composed wholly or partially with "WOOD!!!!" [sic]. Did the DH Mosquito, perhaps the most valuable, versatile and fastest prop. wooden, aircraft to see service in WW2 escape your memory? The ME-262, by the way, had one major flaw: Adolf Hitler. He stupidly insisted it be made into a bomber. I'm an Australian 'republican' so I'm in no way defending the Brits. I am, also, a military historian and ex-air force member, primarily concerned with corroborated facts. (I have copies of official documents that back up over 80 percent of statements here. There would be more if I had time to spend on this reply.) American aviation has achieved magnificent technological advances. So, I have no axe to grind there either. My apologies if anything I said in my post confused you. Cheers, BH P.S. I forgot to mention that during WW2 the British developed some truly terrible aircraft that did little more than slaughter keen, young RAF and Allied aircrews that deserved much better protection and quality control in their brave defence of Britain and democracy. My good mate and author, Michael Veitch has written three excellent books of interviews with British, Australian and New Zealand survivors of the air war over Europe. Those unlucky enough not to fly Hurricanes, Spitfires, Mosquitoes or Lancasters yet survived somehow, attest to the shocking designs and qualities of a large proportion of aircraft available to RAF and Allied Air Force aircrews. BH

[@tenzaemtade6146]

@@BillHalliwell his silence is deafening

[@thedungeondelver]

The Comet fell through the cracks? I'd say the cracks fell through the Comet.

[@johnbockelie3899]

At a high altitude the front end of this plane would fall apart. Also the plane had square passenger windows.

[@sandervanderkammen9230]

@@johnbockelie3899 the shape of the windows is not why they exploded... just the source of some of the initial cracks.

[@petemaly8950]

​@@sandervanderkammen9230 ​​ Kharzeestan Krappenz DiktorBummer Jurkzxoffenz etc and co - they should all note good with much awe & extreme wonder. *UPDATE MORE BREAKING NEWS ETC* The Comet was designed with military use in mind, Nimrod work started at De Havilland in 1953. The committee did not find hundreds of fatal flaws or evidence of design defects, structural defects, defective materials or shoddy workmanship. Ripstop provision was included. Claimed incidents did not involve cracks starting from window corners. The engine & engine intake position had advantages, were not flaws or fatal flaws & were not the cause of any incidents involving any Comet or Nimrod aircraft. Nearly all changes before the Comet 4 were just in case or were previously scheduled improvements. Bow-wing & the 707 story (see b-47 wing folding incidents) is the result of global economics & the well protected & very large domestic US airliner market & active support from the UK with for instance proposed Competing airliners from Vickers & DH being blocked. The 707 was of course a much larger aircraft which as a stressed skin metal airframe aircraft would require a thicker skin anyway. They got lucky at the time essentially. Bow-wing is the result of the large & well protected US domestic airliner market The fate of De Havilland was due to Govt policy Aerospace sector rationalisation & global economics, it was nothing to do with the Comet. A comprehensive, thorough & protracted testing program was carried out on the prototype & it's assemblies. Of course the Comet did indeed have Ripstop stop provision. De Havilland (Of England) Comets were not grounded after 1970 due to structural problems. *_It's interesting that some of the aircraft on the list should really have been noticeably safer than the Comet due to being a similar type but of much later design & manufacture but they definately were not safer._* How things were back then - *_Accident losses - % of aircraft built._* DeHavilland Comet 4 UK 14% DeHavilland Comet all mks 17% Vickers VC10 UK 5% *_The DH Comet had better safety than or similar safety to many other commercial passenger aircraft of a similar era_* Douglas DC-1 99% Douglas DC-2 47% Douglas DC-3 30% Douglas DC-4 26% Boeing s300 72% Boeing 307 70% Boeing 247 48% Boeing 707 20% Lockheed L-049/149 Constellation 30% Lockheed Electra Turboprop 29% Fairchild FH-227 30% McDonnell Douglas DC-8 14% Sud Aviation Caravelle 15% Canadair CL-44 Turboprop 46% Convair CV-580 Turboprop 22% A comparison of more recent aircraft. Accident losses comparison examples. 1970s - 1980s % of total Aircraft built Similar aircraft type, date / decade, useage, size. Biz Jets BAe-125-800 1.7 % Beechcraft Beechjet 400 2.2 % Cessna 550 Citation II 7.1 % Learjet 35 / 36 12 % Beechcraft 1900 6% Dassault Falcon 10 11.5% Aérospatiale SN.601 22.5% Medium size jets / Turboprops. BAe-146 5.1% Fokker 100 6% McDonnell Douglas DC-9-30 9.5% Fairchild FH-227 30% McDonnell Douglas DC-8 14% Canadair CL-44 Turboprop 46% Convair CV-580 Turboprop 22% Beechcraft, Fokker, McDonnell Douglass, Learjet, Fairchild, Aerospatiale, Canadair, Convair companies defunct. All Comets, including some Comet 1s, had full civilian use certification at some point after 1954, civilian use certification only being withdrawn after commercial flying stopped. Examples were flying until 1997 - one example did a signals research global circumnavigation flight series in 1993 via Australia virtually without a rest travelling 28000 miles, only had an ice warning indicator issue during the flights. *The DH Comet - World Firsts.* 1st gas turbine jet powered airliner. 1st high altitude 8psi pressurised full fuselage length passenger cabin airliner, not a trivial feature as structure strength required for pressurisation considerably exceeded strength required for normal flying stress. Nobody else had done anything similar before the Comet. The b-47 used 2 relatively small, heavily built pressurised modules (the aircraft where 6 had their wings fold up in 2 months while flying & some had their wings fall off while parked). The 1937 Boeing piston engined airliner pressurised passenger cabin was pressurised to 2 psi only - in fact that could easily be done as the normal unpressurized fuselage cabin structure strength for flying stresses only was all that was needed to be adequate so no significant weight increase issues needed addressing. 1st all hydraulically powered flying surface controls & actuators airliner with under carriage wheel disk brakes + ABS. 1st jet airliner to cross the Atlantic. 1st jet aircraft to do a world circumnavigation flights series. *Of course De Havilland had prior experience building many all metal construction airframe aircraft including thousands of jet powered fighter aircraft that were primarily of metal construction with pressurised cockpits & jet engines built by De-Havilland & we know the world's first all metal construction airframe airliner was built in England in the 1920s by Handley Page.* *_De Havilland did indeed always work to better than industry standards at the time, used up to date knowledge for the design & no evidence of negligence or criminal negligence was ever produced in relation to the DH Comet._* The course of De Havilland & the general UK aerospace industry sector was not affected even slightly by the DH Comet. The course of national aerospace sectors obviously being similar & inevitable in many countries. *_Other interesting World firsts_* _World's first turboprop aircraft._ *Vickers Viscount Turboprop Airliner 1947.* *A 1945 Gloster Meteor Aircraft with Turboprop Gas Turbine Engine.* They might like to answer these questions. *Which airline has just ordered* *60 RR England Trent XWB Engines* *& What aircraft are the engines for?* _Bonus question for 10 points._ Which country has the *World's Highest Combined Per Capita* *Nuclear + Defence + Aerospace Sector Activity?* 👍 & 🙂 & of course 😎 indeed. *C H E E R S* & without doubt - _Toodle_ -PIP- *Old* *_C H A P._* This line left not blank intentionally. . .... . ... .. . . ... .. ... .... .... ............ ..... . Ivcxivcxiv cxcxcvccbccc xcxiivxccxv ccvvcvvvvvv vivcxiccvccvxxccvvv.

[@nicolek4076]

You can always thank De Havilland for having done the work and for warning Boeing and Douglas about the problems of fatigue cracks (which were poorly understood), saving them them from having to learn the hard way, too. I've always felt that this openness has not been sufficiently acknowledged. It was a very beautiful aircraft and very comfortable (I flew in one in 1965) - much quieter and smoother than planes such as the Bristol Britannia.

[@sandervanderkammen9230]

BOEING was building modern all metal pressurized passenger airliners a decade earlier... when DeHaviland was still building WOOD biplanes.

[@sandervanderkammen9230]

@John Higgins But the Mosquito was not a durable or safe aircraft... in fact there are no original Mosquitos in airworthy condition due to their fragile wooden structure does not age well.

[@petemaly8950]

​​@sandervanderkammen9230 ​ Kharzeestan Krappenz DiktorBummer Jurkzxoffenz etc and co - they should all note good with much awestruckness & extreme wonderment. *UPDATE MORE BREAKING NEWS ETC* De Havilland built many all metal construction airframe aircraft & pressurised aircraft & of course were building jet engines many years before the Comet. The fate of De Havilland was due to Govt policy Aerospace sector rationalisation & global economics, it was nothing to do with the Comet. A comprehensive, thorough & protracted testing program was carried out on the prototype & it's assemblies. Of course the Comet did indeed have Ripstop stop provision. De Havilland (Of England) Comets were not grounded after 1970 due to structural problems. *_It's interesting that some of the aircraft on the list should really have been noticeably safer than the Comet due to being a similar type but of much later design & manufacture but they definately were not safer._* How things were back then - *_Accident losses - % of aircraft built._* DeHavilland Comet 4 UK 14% DeHavilland Comet all mks 17% Vickers VC10 UK 5% *_The DH Comet had better safety than or similar safety to many other commercial passenger aircraft of a similar era_* Douglas DC-1 99% Douglas DC-2 47% Douglas DC-3 30% Douglas DC-4 26% Boeing s300 72% Boeing 307 70% Boeing 247 48% Boeing 707 20% Lockheed L-049/149 Constellation 30% Lockheed Electra Turboprop 29% Fairchild FH-227 30% McDonnell Douglas DC-8 14% Sud Aviation Caravelle 15% Canadair CL-44 Turboprop 46% Convair CV-580 Turboprop 22% A comparison of more recent aircraft. Accident losses comparison examples. 1970s - 1980s % of total Aircraft built Similar aircraft type, date / decade, useage, size. Biz Jets BAe-125-800 1.7 % Beechcraft Beechjet 400 2.2 % Cessna 550 Citation II 7.1 % Learjet 35 / 36 12 % Beechcraft 1900 6% Dassault Falcon 10 11.5% Aérospatiale SN.601 22.5% Medium size jets / Turboprops. BAe-146 5.1% Fokker 100 6% McDonnell Douglas DC-9-30 9.5% Fairchild FH-227 30% McDonnell Douglas DC-8 14% Canadair CL-44 Turboprop 46% Convair CV-580 Turboprop 22% Beechcraft, Fokker, McDonnell Douglass, Learjet, Fairchild, Aerospatiale, Canadair, Convair companies defunct. All Comets, including some Comet 1s, had full civilian use certification at some point after 1954, civilian use certification only being withdrawn after commercial flying stopped. Examples were flying until 1997 - one example did a signals research global circumnavigation flight series in 1993 via Australia virtually without a rest travelling 28000 miles, only had an ice warning indicator issue during the flights. *The DH Comet - World Firsts.* 1st gas turbine jet powered airliner. 1st high altitude 8psi pressurised full fuselage length passenger cabin airliner, not a trivial feature as structure strength required for pressurisation considerably exceeded strength required for normal flying stress. Nobody else had done anything similar before the Comet. The b-47 used 2 relatively small, heavily built pressurised modules (the aircraft where 6 had their wings fold up in 2 months while flying & some had their wings fall off while parked). The 1937 Boeing piston engined airliner pressurised passenger cabin was pressurised to 2 psi only - in fact that could easily be done as the normal unpressurized fuselage cabin structure strength for flying stresses only was all that was needed to be adequate so no significant weight increase issues needed addressing. 1st all hydraulically powered flying surface controls & actuators airliner with under carriage wheel disk brakes + ABS. 1st jet airliner to cross the Atlantic. 1st jet aircraft to do a world circumnavigation flights series. *Of course De Havilland had prior experience building many all metal construction airframe aircraft including thousands of jet powered fighter aircraft that were primarily of metal construction with pressurised cockpits & jet engines built by De-Havilland & we know the world's first all metal construction airframe airliner was built in England in the 1920s by Handley Page.* *_De Havilland did indeed always work to better than industry standards at the time, used up to date knowledge for the design & no evidence of negligence or criminal negligence was ever produced in relation to the DH Comet._* The course of De Havilland & the general UK aerospace industry sector was not affected even slightly by the DH Comet. The course of national aerospace sectors obviously being similar & inevitable in many countries. *_Other interesting World firsts_* _World's first turboprop aircraft._ *Vickers Viscount Turboprop Airliner 1947.* *A 1945 Gloster Meteor Aircraft with Turboprop Gas Turbine Engine.* They might like to answer these questions. *Which airline has just ordered* *60 RR England Trent XWB Engines* *& What aircraft are the engines for?* _Bonus question for 10 points._ Which country has the *World's Highest Combined Per Capita* *Nuclear + Defence + Aerospace Sector Activity?* 👍 & 🙂 & of course 😎 indeed. *C H E E R S* & without doubt - _Toodle_ -PIP- *Old* *_C H A P._* . .... . ... ... . ... .. ... .... ... ..... . Ixivcx. xcxiivx

[@ybing]

every plane crash make flying safer, sadly it does has a great expenses to paid

[@q300SBB]

Very good MP team. I’m most impressed that you went into the route cause, i.e. the punch method to rivet the skin. Many productions stop at the square windows being the culprit.

[@sandervanderkammen9230]

Good comment. Insufficient skin thickness, lack of doubler joints and bad riveting was the ultimate cause of the catastrophic structure failures.

[@Multicsfan]

It wasn't bad riveting but with how the rivet holes were made. The holes were punched by the rivet. If they had drilled the holes or used another method it would have worked. Another video indicated they tested the airframe but did one test first which covered up the second problem. If they had used separate airframes in testing the problem would have shown up.

[@sandervanderkammen9230]

​@@MulticsfanThe workmanship and techniques were both found to be well below standards of the day, inspection was also inadequate.

[@petemaly8950]

​@@sandervanderkammen9230 ​@sandervanderkammen9230 ​@sandervanderkammen9230 ​ Kharzeestan Krappenz DiktorBummer Jurkzxoffenz etc and co - they should all note good with much awestruckness & extreme wonderment. *UPDATE MORE BREAKING NEWS ETC* The fate of De Havilland was due to Govt policy Aerospace sector rationalisation & global economics, it was nothing to do with the Comet. A comprehensive, thorough & protracted testing program was carried out on the prototype & it's assemblies. Of course the Comet did indeed have Ripstop stop provision. De Havilland (Of England) Comets were not grounded after 1970 due to structural problems. *_It's interesting that some of the aircraft on the list should really have been noticeably safer than the Comet due to being a similar type but of much later design & manufacture but they definately were not safer._* How things were back then - *_Accident losses - % of aircraft built._* DeHavilland Comet 4 UK 14% DeHavilland Comet all mks 17% Vickers VC10 UK 5% *_The DH Comet had better safety than or similar safety to many other commercial passenger aircraft of a similar era_* Douglas DC-1 99% Douglas DC-2 47% Douglas DC-3 30% Douglas DC-4 26% Boeing s300 72% Boeing 307 70% Boeing 247 48% Boeing 707 20% Lockheed L-049/149 Constellation 30% Lockheed Electra Turboprop 29% Fairchild FH-227 30% McDonnell Douglas DC-8 14% Sud Aviation Caravelle 15% Canadair CL-44 Turboprop 46% Convair CV-580 Turboprop 22% A comparison of more recent aircraft. Accident losses comparison examples. 1970s - 1980s % of total Aircraft built Similar aircraft type, date / decade, useage, size. Biz Jets BAe-125-800 1.7 % Beechcraft Beechjet 400 2.2 % Cessna 550 Citation II 7.1 % Learjet 35 / 36 12 % Beechcraft 1900 6% Dassault Falcon 10 11.5% Aérospatiale SN.601 22.5% Medium size jets / Turboprops. BAe-146 5.1% Fokker 100 6% McDonnell Douglas DC-9-30 9.5% Fairchild FH-227 30% McDonnell Douglas DC-8 14% Canadair CL-44 Turboprop 46% Convair CV-580 Turboprop 22% Beechcraft, Fokker, McDonnell Douglass, Learjet, Fairchild, Aerospatiale, Canadair, Convair companies defunct. All Comets, including some Comet 1s, had full civilian use certification at some point after 1954, civilian use certification only being withdrawn after commercial flying stopped. Examples were flying until 1997 - one example did a signals research global circumnavigation flight series in 1993 via Australia virtually without a rest travelling 28000 miles, only had an ice warning indicator issue during the flights. *The DH Comet - World Firsts.* 1st gas turbine jet powered airliner. 1st high altitude 8psi pressurised full fuselage length passenger cabin airliner, not a trivial feature as structure strength required for pressurisation considerably exceeded strength required for normal flying stress. Nobody else had done anything similar before the Comet. The b-47 used 2 relatively small, heavily built pressurised modules (the aircraft where 6 had their wings fold up in 2 months while flying & some had their wings fall off while parked). The 1937 Boeing piston engined airliner pressurised passenger cabin was pressurised to 2 psi only - in fact that could easily be done as the normal unpressurized fuselage cabin structure strength for flying stresses only was all that was needed to be adequate so no significant weight increase issues needed addressing. 1st all hydraulically powered flying surface controls & actuators airliner with under carriage wheel disk brakes + ABS. 1st jet airliner to cross the Atlantic. 1st jet aircraft to do a world circumnavigation flights series. *Of course De Havilland had prior experience building many all metal construction airframe aircraft including thousands of jet powered fighter aircraft that were primarily of metal construction with pressurised cockpits & jet engines built by De-Havilland & we know the world's first all metal construction airframe airliner was built in England in the 1920s by Handley Page.* *_De Havilland did indeed always work to better than industry standards at the time, used up to date knowledge for the design & no evidence of negligence or criminal negligence was ever produced in relation to the DH Comet._* The course of De Havilland & the general UK aerospace industry sector was not affected even slightly by the DH Comet. The course of national aerospace sectors obviously being similar & inevitable in many countries. *_Other interesting World firsts_* _World's first turboprop aircraft._ *Vickers Viscount Turboprop Airliner 1947.* *A 1945 Gloster Meteor Aircraft with Turboprop Gas Turbine Engine.* They might like to answer these questions. *Which airline has just ordered* *60 RR England Trent XWB Engines* *& What aircraft are the engines for?* _Bonus question for 10 points._ Which country has the *World's Highest Combined Per Capita* *Nuclear + Defence + Aerospace Sector Activity?* 👍 & 🙂 & of course 😎 indeed. *C H E E R S* & without doubt - _Toodle_ -PIP- *Old* *_C H A P._* . .... . ... ... . ... .. ... .... ... ..... . Ivcxivcxivvcvvcx xcxiivxccxvccv vivcxiccvc cvxxcc

[@techauthor324]

You forgot to mention that the DH Comet continued to fly, long after commercial retirement, as Nimrod with the RAF.

[@sandervanderkammen9230]

The Hawker Siddley HS.801 Nimrod is not a Comet, it has a completely different type certification and shares nothing in common with the early failed airliner design.

[@techauthor324]

Well, technically you could be correct, but the fins that i used to build used the same jigs for Comet and Nimrod.

[@sandervanderkammen9230]

@@techauthor324 True, much of the tooling and fixtures were recycled and repurposed by Hawker Siddley, much of the de Havilland tooling was still NRW or like new as production of the Comet ceased after just 114 total airframes.

[@AtheistOrphan]

Fond memories of watching the last Dan Air Comets at Gatwick back in the day.

[@omegalightning5715]

Does one of the space shuttles qualify as a megaproject?

[@NurmYokai]

Missing Bonus Facts. 1948 - “English novelist and aeronautical engineer” Nevil Shute publishes the novel “No Highway.” Where the protagonist claims a certain aircraft will crash due to metal fatigue. 1951 - The film “No Highway in the Sky” is released. It is based on the novel “No Highway.” The fictional aircraft was the “Rutland Reindeer.” 1952 - The beginning of the de Havilland Comet crashes, due to metal fatigue. To be obvious, the other origin for “Comet” would be Santa’s reindeer. Not that this would be the only time fiction matched real life. "The Wreck of the Titan" (1898) where the fictional British liner Titan in the month of April strikes an iceberg and sinks in the North Atlantic. The Titan has insufficient lifeboats. RMS Titanic suffered the same fate in 1912.

[@sandervanderkammen9230]

Metal fatigue was in fact well-known and understood before the Comet Disaster... Boeing, Junkers, Douglas and Lockheed were building pressurized passenger airliners years before the Comet Disaster.

[@jamesmcgarrigle8671]

Actually the Comet was beaten into service by the Russian Tu-104

[@pushing2throttles]

If aircraft manufacturing aren't mega projects, take a look at the Everett, Washington Boeing 747 assembly building. That building is so huge...I can't describe it with only a few words, but multiple Queen's of the sky are built, SIMULTANEOUSLY! That's MEGA

[@rickhobson3211]

"Fallen through the cracks of history." Yeah... and out of the sky, too. :P

[@PenzancePete]

Boeing 737 Max anyone?

[@sandervanderkammen9230]

@@PenzancePete The Max is back... The Comet 1 had its airworthiness certification was permanently revoked.

[@matthewq4b]

@@sandervanderkammen9230 It was not permanently revoked it was suspended till the 1 airframes were upgraded to Comet 2 sepcs.

[@sandervanderkammen9230]

@@matthewq4b Sorry, but that is incorrect. The Comet 1s airworthiness certification was in fact permanently revoked. No Comet 1s ever returned to commercial passenger service.

[@sandervanderkammen9230]

@@matthewq4b Comet 2s only saw service with the RAF or for testing under a restricted temporary airworthiness status with a very restricted number of airframe service hours before they too were forced to be scrapped due to metal fatigue.

[@cmulder002]

the picture of the pressure testing shown was AFTER the crashes ; it was done to find the failure points while the fleet was grounded.

[@boneo_the_muso3493]

YEAH!!! You done the comet!! I commented ages ago for a vid on the comet and didn't even get one like.

[@Sh_rib]

Have a like on this comment then lol

[@boneo_the_muso3493]

@@Sh_rib Ah cheers bruv. one love👍

[@oliverwalton5314]

You should do a video on the English electric lighting

[@alexius23]

There was a James Stewart film called “No Highway in the Sky” that dealt with a similar story

[@simonbeaird7436]

IIRC the film is called 'No Highway in the Sky'. It's based on a novel by Nevil Shute, who was an aeronautical engineer as well as an author.

[@alexius23]

@@simonbeaird7436 d’oh.....my bad

[@AnotherPointOfView944]

One of my favourite films

[@brianbaas8650]

3:36 Fun fact: the picture you're seeing here is of Madurodam. A miniture version of the netherlands, built up over many years. And it's still being updated to this day

[@PiersLawsonBrown1972]

No mention of the Nimrod, which kept the Comet airframe flying until 2011.

[@sandervanderkammen9230]

The Hawker Siddley HS.801 Nimrod is not a Comet, it is an completely different design and shares no parts or structures in common. Both aircraft were plagued by metal fatigue problems

[@sarrassgaming1537]

You really should do a video on the concrete ships made in ww2 by various nations. Actual ships, made from concrete. Cool stuff.

[@erika002]

Megaprojects is becoming an aviation channel...... *_looks at Wendover Productions_*

[@nts821]

planes get most views

[@mammuchan8923]

Can there be such a thing as too many plane videos 😅

[@recka5000]

And I'm here for it

[@Millsy.g]

Here is a good idea. the Rogers Pass summit rail tunnel (Mount Macdonald Tunnel) and the Spiral Tunnels in the Kicking Horse Pass (Both in British Columbia Canada). Huge megaprojects that you can go visit today.

[@drgonzo305]

Moving the city of Chicago, side project. Making a jet plane, megaproject...... I'm gonna need to see the criteria for your classification system

[@Chris_at_Home]

It is quite a coincidence that both the Comet and Lockheed Electra started as troubled passenger aircraft that had crashes but they really came of age in Military ASW as the Nimrod and Orion.

[@sandervanderkammen9230]

Lockheed and de Havilland could not be more different, Lockheed is hugely successful and supplies the RAFs most advanced jet fighter... while d-H was destroyed by the _Comet Disaster_ and no longer exists.

[@Chris_at_Home]

@@sandervanderkammen9230 it’s like no one wanted to buy the Nimrod where even though the Electra had early problems it flew on for years. I flew in one a few times going to Dutch Harbor in the 1990s. Lockheed was already building other military aircraft like the C-130. Then but the 60s they had the C-141. I flew in a 141 once from Maine to the Azores. I flew quite a bit in P-3 as an avionics tech. I even went to a Nimrod base in SW England in 1974.

[@petemaly8950]

​​@@sandervanderkammen9230 ​​ Kharzeestan Krappenz DiktorBummer Jurkzxoffenz etc and co - they should all note good with much awe & extreme wonder. *UPDATE MORE BREAKING NEWS ETC* The Comet was designed with military use in mind, Nimrod work started at De Havilland in 1953. The committee did not find hundreds of fatal flaws or evidence of design defects, structural defects, defective materials or shoddy workmanship. Ripstop provision was included. Claimed incidents did not involve cracks starting from window corners. The engine & engine intake position had advantages, were not flaws or fatal flaws & were not the cause of any incidents involving any Comet or Nimrod aircraft. Nearly all changes before the Comet 4 were just in case or were previously scheduled improvements. Bow-wing & the 707 story (see b-47 wing folding incidents) is the result of global economics & the well protected & very large domestic US airliner market & active support from the UK with for instance proposed Competing airliners from Vickers & DH being blocked. The 707 was of course a much larger aircraft which as a stressed skin metal airframe aircraft would require a thicker skin anyway. They got lucky at the time essentially. Bow-wing is the result of the large & well protected US domestic airliner market The fate of De Havilland was due to Govt policy Aerospace sector rationalisation & global economics, it was nothing to do with the Comet. A comprehensive, thorough & protracted testing program was carried out on the prototype & it's assemblies. Of course the Comet did indeed have Ripstop stop provision. De Havilland (Of England) Comets were not grounded after 1970 due to structural problems. *_It's interesting that some of the aircraft on the list should really have been noticeably safer than the Comet due to being a similar type but of much later design & manufacture but they definately were not safer._* How things were back then - *_Accident losses - % of aircraft built._* DeHavilland Comet 4 UK 14% DeHavilland Comet all mks 17% Vickers VC10 UK 5% *_The DH Comet had better safety than or similar safety to many other commercial passenger aircraft of a similar era_* Douglas DC-1 99% Douglas DC-2 47% Douglas DC-3 30% Douglas DC-4 26% Boeing s300 72% Boeing 307 70% Boeing 247 48% Boeing 707 20% Lockheed L-049/149 Constellation 30% Lockheed Electra Turboprop 29% Fairchild FH-227 30% McDonnell Douglas DC-8 14% Sud Aviation Caravelle 15% Canadair CL-44 Turboprop 46% Convair CV-580 Turboprop 22% A comparison of more recent aircraft. Accident losses comparison examples. 1970s - 1980s % of total Aircraft built Similar aircraft type, date / decade, useage, size. Biz Jets BAe-125-800 1.7 % Beechcraft Beechjet 400 2.2 % Cessna 550 Citation II 7.1 % Learjet 35 / 36 12 % Beechcraft 1900 6% Dassault Falcon 10 11.5% Aérospatiale SN.601 22.5% Medium size jets / Turboprops. BAe-146 5.1% Fokker 100 6% McDonnell Douglas DC-9-30 9.5% Fairchild FH-227 30% McDonnell Douglas DC-8 14% Canadair CL-44 Turboprop 46% Convair CV-580 Turboprop 22% Beechcraft, Fokker, McDonnell Douglass, Learjet, Fairchild, Aerospatiale, Canadair, Convair companies defunct. All Comets, including some Comet 1s, had full civilian use certification at some point after 1954, civilian use certification only being withdrawn after commercial flying stopped. Examples were flying until 1997 - one example did a signals research global circumnavigation flight series in 1993 via Australia virtually without a rest travelling 28000 miles, only had an ice warning indicator issue during the flights. *The DH Comet - World Firsts.* 1st gas turbine jet powered airliner. 1st high altitude 8psi pressurised full fuselage length passenger cabin airliner, not a trivial feature as structure strength required for pressurisation considerably exceeded strength required for normal flying stress. Nobody else had done anything similar before the Comet. The b-47 used 2 relatively small, heavily built pressurised modules (the aircraft where 6 had their wings fold up in 2 months while flying & some had their wings fall off while parked). The 1937 Boeing piston engined airliner pressurised passenger cabin was pressurised to 2 psi only - in fact that could easily be done as the normal unpressurized fuselage cabin structure strength for flying stresses only was all that was needed to be adequate so no significant weight increase issues needed addressing. 1st all hydraulically powered flying surface controls & actuators airliner with under carriage wheel disk brakes + ABS. 1st jet airliner to cross the Atlantic. 1st jet aircraft to do a world circumnavigation flights series. *Of course De Havilland had prior experience building many all metal construction airframe aircraft including thousands of jet powered fighter aircraft that were primarily of metal construction with pressurised cockpits & jet engines built by De-Havilland & we know the world's first all metal construction airframe airliner was built in England in the 1920s by Handley Page.* *_De Havilland did indeed always work to better than industry standards at the time, used up to date knowledge for the design & no evidence of negligence or criminal negligence was ever produced in relation to the DH Comet._* The course of De Havilland & the general UK aerospace industry sector was not affected even slightly by the DH Comet. The course of national aerospace sectors obviously being similar & inevitable in many countries. *_Other interesting World firsts_* _World's first turboprop aircraft._ *Vickers Viscount Turboprop Airliner 1947.* *A 1945 Gloster Meteor Aircraft with Turboprop Gas Turbine Engine.* They might like to answer these questions. *Which airline has just ordered* *60 RR England Trent XWB Engines* *& What aircraft are the engines for?* _Bonus question for 10 points._ Which country has the *World's Highest Combined Per Capita* *Nuclear + Defence + Aerospace Sector Activity?* 👍 & 🙂 & of course 😎 indeed. *C H E E R S* & without doubt - _Toodle_ -PIP- *Old* *_C H A P._* This line left not blank intentionally. . .... . ... .. . . ... .. ... .... .... ............ ..... . Ivcxivcxivxcv cxcxcvccbxcvcvx xcxiivxccxvcv ccvvcvvvxcx vivcxiccvccvxxccvvv.

[@Texassince1836]

Well im early. Some body pass the *BLAZE*

[@jimtalbott9535]

I'll put in my usual plug for the USAF Heavy Press Program - acquiring the technology to reduce or eliminate those rivets in the construction of jet aircraft! I'd also suggest the CANOL project, during WW2 - ancillary to the Alaska Highway project, but MASSIVE in scale.

[@SovereignwindVODs]

I appreciate the willingness of those engineers to admit their designs were only as safe as they were because of the comets failures.

[@sandervanderkammen9230]

The Comet Disaster was the worst engineering failure in commercial aviation history. The construction of pressurized passenger airliners was not new, it was well-known and understood by the leading manufacturers. DeHaviland lagged decades behind, they were still producing biplane airliners made out of WOOD and fabric!!!!

[@asiesjefa1758]

@@sandervanderkammen9230 yes but what it wasn't well known and understood was the behaviour of cracks when they are under fatigue and THIS was what caused the accidents not just the pressurisation.

[@sandervanderkammen9230]

@John Higgins You don't get it do you? DeHaviland was decades behind in aircraft construction techniques. It had very little experience with building aircraft structures out of aluminum and almost no experience at all in safe use of metal riveted joints. The Comet was clearly beyond the technical ability of the company to design and produce..

[@sandervanderkammen9230]

@@asiesjefa1758 Apparently you do not understand... DeHaviland was more than a decade behind in transport aircraft design and construction. Metal fatigue was in fact well-known and understood. The Boeing 307 and 377, the Douglas DC4 and DC6, The Lockheed Constellation were all flying with pressurized metal airframe structures. long before the _Comet Disaster._ The Comet remains a shameful example of incompetence and criminal negligence in the aircraft industry.

[@asiesjefa1758]

@@sandervanderkammen9230 I'm just quoting what my university professor of this particular field says and yes, maybe it was known that cracks could spread with fatigue but it wasn't well-known as you assure because if so they would have tried to avoid high stress states (idk how it is said in English that) and they didn't.

[@ErraticPT]

You didn't mention the fact the passenger window shape on early comets contributed more to the fatigue cracks than the rivets alone.

[@sandervanderkammen9230]

Inadequate skin thickness and the lack of doubler joints is what actually caused the catastrophic structure failures... This is why the early planes could not be fixed by simply changing the windows... their airworthiness certification was permanently revoked.

[@ErraticPT]

@@sandervanderkammen9230 Yes, but most (not all) of the riviting failure areas were identified around the unusual square windows. As I said it was a MAJOR factor not the only one, why else would they remove a heavily promoted feature (everyone likes large windows rather than pokey porthole like windows that were the norm until then) if not because they were unsafe on pressurised planes using the technology of the day.

[@sandervanderkammen9230]

@@ErraticPT The technology of the day was to use stronger, much thicker skins and install doubler joints... something DeHaviland in their ignorance failed to do at their own (and the passengers) peril.

[@FQP-7024]

Here's a Megaproject he could do: The Bristol Brabazon giant luxury plane

[@bimblinghill]

That's a good one. Kind of the UK equivalent of Hughes' Spruce Goose (commercially, if not technically).

[@FQP-7024]

@@bimblinghill I am revolted every time i hear that nickname just have it the H-4 and be done with it. (sorry it's at least 1 am here and I hate everything)

[@patrickbrookings]

My dad always used to tell me about this plane. One important thing you forgot to mention is that the windows were square shaped, which was one of the main reasons of the failures. It means that the stresses converge on the corners, which caused cracks around them, and eventually failure. That's why plane windows are now oval shaped, as it evens out the stress over the whole line.

[@sandervanderkammen9230]

Not true, although some cracks originated from the corners of the navigation port and passenger windows. It was the bad fuselage skins, lack of rip-stop doubler joints and shoddy workmanship in the riveting that actually caused the catastrophic structure failures...

[@LeoStaley]

Simon just make an airplanes channel and keep the mega projects here.

[@bondisteve3617]

Very good Simon....thanks!

[@667crash]

Any presentation on the "Comet" also needs to include discussion of the "Avro Canada C102" and the "Tu-104". The "C102" actually flew thirteen-days after the "Comet" on August 10, 1949. The "C102" had a habit of not coming apart in the air and killing large numbers of people like the "Comet". The "C102" was killed by the Canadian Government or it would have probably become the worlds first operational commercial jet airliner. Unfortunately this was going to be a long trend for Canadian Companies. The TU-104 would go on to be the first successful commercial jet airliner. One of the great failings on the "Comet", was the arrogance of its designers, who refused to listen to American, German and Russian designers to not do what they did.

[@killernat1234]

This plane is the same sort of thing as the first iPhone, it wasn’t perfect or flawless but it shaped the industry

[@sandervanderkammen9230]

The Boeing 707 was the plane that revolutionized aircraft travel... the Comet Disaster remains a shameful chapter in aviation history.

[@petemaly8950]

​​@sandervanderkammen9230 ​ Kharzeestan Krappenz DiktorBummer Jurkzxoffenz etc and co - they should all note good with much awestruckness & extreme wonderment. *UPDATE MORE BREAKING NEWS ETC* Bow-wing (see b-47 wing folding incidents) is the result of global economics & a large & well protected domestic airliner market. The 707 happened to be much larger & thus required a thicker stressed skin for flying stress loads. The fate of De Havilland was due to Govt policy Aerospace sector rationalisation & global economics, it was nothing to do with the Comet. A comprehensive, thorough & protracted testing program was carried out on the prototype & it's assemblies. Of course the Comet did indeed have Ripstop stop provision. De Havilland (Of England) Comets were not grounded after 1970 due to structural problems. *_It's interesting that some of the aircraft on the list should really have been noticeably safer than the Comet due to being a similar type but of much later design & manufacture but they definately were not safer._* How things were back then - *_Accident losses - % of aircraft built._* DeHavilland Comet 4 UK 14% DeHavilland Comet all mks 17% Vickers VC10 UK 5% *_The DH Comet had better safety than or similar safety to many other commercial passenger aircraft of a similar era_* Douglas DC-1 99% Douglas DC-2 47% Douglas DC-3 30% Douglas DC-4 26% Boeing s300 72% Boeing 307 70% Boeing 247 48% Boeing 707 20% Lockheed L-049/149 Constellation 30% Lockheed Electra Turboprop 29% Fairchild FH-227 30% McDonnell Douglas DC-8 14% Sud Aviation Caravelle 15% Canadair CL-44 Turboprop 46% Convair CV-580 Turboprop 22% A comparison of more recent aircraft. Accident losses comparison examples. 1970s - 1980s % of total Aircraft built Similar aircraft type, date / decade, useage, size. Biz Jets BAe-125-800 1.7 % Beechcraft Beechjet 400 2.2 % Cessna 550 Citation II 7.1 % Learjet 35 / 36 12 % Beechcraft 1900 6% Dassault Falcon 10 11.5% Aérospatiale SN.601 22.5% Medium size jets / Turboprops. BAe-146 5.1% Fokker 100 6% McDonnell Douglas DC-9-30 9.5% Fairchild FH-227 30% McDonnell Douglas DC-8 14% Canadair CL-44 Turboprop 46% Convair CV-580 Turboprop 22% Beechcraft, Fokker, McDonnell Douglass, Learjet, Fairchild, Aerospatiale, Canadair, Convair companies defunct. All Comets, including some Comet 1s, had full civilian use certification at some point after 1954, civilian use certification only being withdrawn after commercial flying stopped. Examples were flying until 1997 - one example did a signals research global circumnavigation flight series in 1993 via Australia virtually without a rest travelling 28000 miles, only had an ice warning indicator issue during the flights. *The DH Comet - World Firsts.* 1st gas turbine jet powered airliner. 1st high altitude 8psi pressurised full fuselage length passenger cabin airliner, not a trivial feature as structure strength required for pressurisation considerably exceeded strength required for normal flying stress. Nobody else had done anything similar before the Comet. The b-47 used 2 relatively small, heavily built pressurised modules (the aircraft where 6 had their wings fold up in 2 months while flying & some had their wings fall off while parked). The 1937 Boeing piston engined airliner pressurised passenger cabin was pressurised to 2 psi only - in fact that could easily be done as the normal unpressurized fuselage cabin structure strength for flying stresses only was all that was needed to be adequate so no significant weight increase issues needed addressing. 1st all hydraulically powered flying surface controls & actuators airliner with under carriage wheel disk brakes + ABS. 1st jet airliner to cross the Atlantic. 1st jet aircraft to do a world circumnavigation flights series. *Of course De Havilland had prior experience building many all metal construction airframe aircraft including thousands of jet powered fighter aircraft that were primarily of metal construction with pressurised cockpits & jet engines built by De-Havilland & we know the world's first all metal construction airframe airliner was built in England in the 1920s by Handley Page.* *_De Havilland did indeed always work to better than industry standards at the time, used up to date knowledge for the design & no evidence of negligence or criminal negligence was ever produced in relation to the DH Comet._* The course of De Havilland & the general UK aerospace industry sector was not affected even slightly by the DH Comet. The course of national aerospace sectors obviously being similar & inevitable in many countries. *_Other interesting World firsts_* _World's first turboprop aircraft._ *Vickers Viscount Turboprop Airliner 1947.* *A 1945 Gloster Meteor Aircraft with Turboprop Gas Turbine Engine.* They might like to answer these questions. *Which airline has just ordered* *60 RR England Trent XWB Engines* *& What aircraft are the engines for?* _Bonus question for 10 points._ Which country has the *World's Highest Combined Per Capita* *Nuclear + Defence + Aerospace Sector Activity?* 👍 & 🙂 & of course 😎 indeed. *C H E E R S* & without doubt - _Toodle_ -PIP- *Old* *_C H A P._* . .... . ... ... . ... .. ... .... ... ..... . Ivcxivcxivcx xcxiivxccxvccv vivcxiccvccvxxcc.

[@milk-it]

I love how the Comet is referenced against the 747 Jumbo Jet - which is being retired, but it's still the Queen of the skies. Love it.

[@sandervanderkammen9230]

The Boeing 747 is still in production...

[@pattonpending7390]

"Falling through the cracks of history". Sick burn on the DeHavilland.

[@SparkBerry]

The crash investigation that found the riveting defect was revolutionary itself, and changed the way air crash investigations are conducted to this day. It alone could be a Megaproject.

[@sandervanderkammen9230]

Riveting aluminum was well-known and understood in the aircraft industry before the Comet Disaster... DeHaviland never got the memo, they were still building biplanes made out of WOOD and FABRIC in 1949!!!

[@SparkBerry]

@@sandervanderkammen9230 Yes I agree... I'm an aircraft maintenance engineer so I have a background in the subject. What made this different was lack of a knowledge when it came to the pressurizing of the fuselage in combination with the style of rivetting. We are taught even with solid rivets not to allow burrs to remain when drilling as this is a point where cracks can propagate from. This form of rivetting was fine on low performance unpressurized aircraft, but an absolute no go on these jets. The way they investigated and found the problem was game changing at the time

[@sandervanderkammen9230]

@@SparkBerry Not true, riveted aluminum airframes and pressurized cabins were nothing new when the Comet Disaster occurred...

[@sandervanderkammen9230]

@@SparkBerry Alot was learned by DeHaviland, there claim to fame was laminated plywood construction and the use of polyvinyl glue. The company had very little experience with aluminum and almost no experience in riveted fuselage design or fabrication. DeHaviland chose to punch the rivet holes rather than drill, used skins that were much too thin and did not install doubler joints... The Cohen Committee investigations found extremely shoddy workmanship in the riveting including loose rivets, cracked skins from rivets being over driven and misfprmed heads due to the riveting length being incorrect. Unforgettable mistakes today and unacceptable in the 1940s as well.

[@joshfloyd691]

The Berlin airlift would be a pretty good mega project. The us airforce fully supplied the city of Berlin, delivering upto 6000 tons of material everyday, using dirt runways.

[@XSpImmaLion]

ROFL, the coach snark, on point

[@abraarmohammadshafi1779]

Love Simon's way of saying miles per hour......miles per aaah

[@AlbertCalis]

Simon, please do a Megaprojects on the Bristol Brabazon.

[@topherstokes]

Really enjoy the shows Simon . Always great content . How about an episode on the construction of the watershed project for New York City . It's over 100 years old and they're still working on it . The water comes from the Catskill Mountains and the tunnels are huge . They were even in one of the Die Hard movies . Could be a good show .

[@tomhemming9236]

My Great Grandfather, Aubrey Burke worked on designing the comet, and later it's military variant the nimrod at DeHaviland and Hawker-Siddeley respectively, one of my late grandmothers early memories was waiting by the phone after some of the early crashes to hand it to him whenever another member of the press called him.

[@sandervanderkammen9230]

Wow, so he was one of the people responsible for the worst engineering failure in history of commercial jet aircraft? The Comet Disaster investigations revealed 100s of the fatal design flaws and examples of shoddy workmanship

[@Peppa_Wiggles23]

​​@@sandervanderkammen9230 ​​​@sandervanderkammen9230 Kharzeestan Krappenz DiktorBummer Jurkzxoffenz etc and co - they should all note good with much awestruckness & extreme wonderment. *UPDATE MORE BREAKING NEWS ETC* There were not 100s of fatal flaws in the design of the Comet. Most changes made were just in case changes & were mostly previously scheduled improvements obviously. De Havilland (Of England) Comets were not grounded after 1970 due to structural problems. *_It's interesting that some of the aircraft on the list should really have been noticeably safer than the Comet due to being a similar type but of much later design & manufacture but they definately were not safer._* How things were back then - *_Accident losses - % of aircraft built._* DeHavilland Comet 4 UK 14% DeHavilland Comet all mks 17% Vickers VC10 UK 5% *_The DH Comet had better safety than or similar safety to many other commercial passenger aircraft of a similar era_* Douglas DC-1 99% Douglas DC-2 47% Douglas DC-3 30% Douglas DC-4 26% Boeing s300 72% Boeing 307 70% Boeing 247 48% Boeing 707 20% Lockheed L-049/149 Constellation 30% Lockheed Electra Turboprop 29% Fairchild FH-227 30% McDonnell Douglas DC-8 14% Sud Aviation Caravelle 15% Canadair CL-44 Turboprop 46% Convair CV-580 Turboprop 22% A comparison of more recent aircraft. Accident losses comparison examples. 1970s - 1980s % of total Aircraft built Similar aircraft type, date / decade, useage, size. Biz Jets BAe-125-800 1.7 % Beechcraft Beechjet 400 2.2 % Cessna 550 Citation II 7.1 % Learjet 35 / 36 12 % Beechcraft 1900 6% Dassault Falcon 10 11.5% Aérospatiale SN.601 22.5% Medium size jets / Turboprops. BAe-146 5.1% Fokker 100 6% McDonnell Douglas DC-9-30 9.5% Fairchild FH-227 30% McDonnell Douglas DC-8 14% Canadair CL-44 Turboprop 46% Convair CV-580 Turboprop 22% Beechcraft, Fokker, McDonnell Douglass, Learjet, Fairchild, Aerospatiale, Canadair, Convair companies defunct. All Comets, including some Comet 1s, had full civilian use certification at some point after 1954, civilian use certification only being withdrawn after commercial flying stopped. Examples were flying until 1997 - one example did a signals research global circumnavigation flight series in 1993 via Australia virtually without a rest travelling 28000 miles, only had an ice warning indicator issue during the flights. The prototypes & prototype assemblies were of course subjected to an extensive & protracted programme of testing. *The DH Comet - World Firsts.* 1st gas turbine jet powered airliner. 1st high altitude 8psi pressurised full fuselage length passenger cabin airliner, not a trivial feature as structure strength required for pressurisation considerably exceeded strength required for normal flying stress. Nobody else had done anything similar before the Comet. The b-47 used 2 relatively small, heavily built pressurised modules (the aircraft where 6 had their wings fold up in 2 months while flying & some had their wings fall off while parked). The 1937 Boeing piston engined airliner pressurised passenger cabin was pressurised to 2 psi only - in fact that could easily be done as the normal unpressurized fuselage cabin structure strength for flying stresses only was all that was needed to be adequate so no significant weight increase issues needed addressing. 1st all hydraulically powered flying surface controls & actuators airliner with under carriage wheel disk brakes + ABS. 1st jet airliner to cross the Atlantic. 1st jet aircraft to do a world circumnavigation flights series. *Of course De Havilland had prior experience building many all metal construction airframe aircraft including thousands of jet powered fighter aircraft that were primarily of metal construction with pressurised cockpits & jet engines built by De-Havilland & we know the world's first all metal construction airframe airliner was built in England in the 1920s by Handley Page.* *_De Havilland did indeed always work to better than industry standards at the time, used up to date knowledge for the design & no evidence of negligence or criminal negligence was ever produced in relation to the DH Comet._* The course of De Havilland & the general UK aerospace industry sector was not affected even slightly by the DH Comet. The course of national aerospace sectors obviously being similar & inevitable in many countries. *_Other interesting World firsts_* _World's first turboprop aircraft._ *Vickers Viscount Turboprop Airliner 1947.* *A 1945 Gloster Meteor Aircraft with Turboprop Gas Turbine Engine.* They might like to answer these questions. *Which airline has just ordered* *60 RR England Trent XWB Engines* *& What aircraft are the engines for?* _Bonus question for 10 points._ Which country has the *World's Highest Combined Per Capita* *Nuclear + Defence + Aerospace Sector Activity?* 👍 & 🙂 & of course 😎 indeed. *C H E E R S* & without doubt - _Toodle_ -PIP- *Old* *_C H A P._* . .... . ... . ... .. ... .... ... .... Ivcxivcxivc xcxiivxvivcxiccxxcc

[@Nickopacicjr]

A Megaproject suggestion for you: US Steel in Gary, Indiana. A steel mill built on sand dunes on Lake Michigan.