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The Boeing 747 begins its final descent

theatlantic.com

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Re: The Boeing 747 begins its final descent

#351

Post by dotancohen »

sidewndr46 wrote: post #198
Animats wrote: post #107

Earlier quoted context omitted.

That was also said about the B-707, which was supposed to have some parts commonality with their KC-135 Stratotanker built for the USAF. But as development progressed, the airliner and the tanker diverged. The B-747 went through a similar process. Boeing was proposing a big cargo aircraft to the USAF (the CX-HLS), but that was never built. Lockheed got the C-5 contract instead, which satisfied the USAF's need for a r…

The Lockheed L-100 Hercules does exist and is apparently a civilian C-130

You're going to love the TU-114!

Re: The Boeing 747 begins its final descent

#352

Post by dotancohen »

wolvoleo wrote: post #121
sidewndr46 wrote: post #95

Earlier quoted context omitted.

This seems like an odd version of the story. My understanding is Boeing designed lots of military aircraft, not all reached production. The 747 is the result of some of that design work.

That makes sense because a high cockpit also combines well with nose loading which some military freighters have.

Nose loading was the reason the 747 had the aircrew sit on the top floor. It was thought that the SST project would displace all extent subsonic airliners, so the 747 was designed to be easily configured for freight after a short timeframe serving pax.

Re: The Boeing 747 begins its final descent

#353

Post by dotancohen »

fransje26 wrote: post #280
addaon wrote: post #29

Earlier quoted context omitted.

> Top floor existed at all because it was Boeing's entry for a heavy cargo plane competition Yes, but it turns out the hump is great for area ruling (aerodynamic drag reduction at transonic speeds), as observed by the 747-300's extended hump giving lower drag (but higher weight, of course) than the short-hump versions.

Slightly pedantic, but this is not completely correct. It had a lower Cd with the extended hump, but it still had a higher drag, due to the larger wetted area.

Could you expand upon that for us interested laymen?

Re: The Boeing 747 begins its final descent

#354

Post by dotancohen »

bobthepanda wrote: post #258
pfdietz wrote: post #3

Earlier quoted context omitted.

I think the top floor is there because the crew cabin has to be high so the nose can swing up. The cables and wiring from the cabin can't be easily disconnected to allow such access. You will notice other large cargo variants of airliners load cargo only through the side of the fuselage.

This is correct. For context, when the 747 was being developed, simultaneously Boeing was developing the SST, Britain and France were developing Concorde, and the Soviets had their own supersonic Tupolevs in development. Boeing was anticipating that supersonic aircraft would render the subsonic 747 obsolete for passengers overnight, so it was designed to be easily convertible to freight.

And interestingly, the Tu-144 flew passengers before the Concorde did!

Re: The Boeing 747 begins its final descent

#355

Post by dotancohen »

WalterBright wrote: post #150
anovikov wrote: post #2

But really, it was just about four-engine planes becoming too expensive to run. Two-engine planes won. 777 burns 30% less fuel per passenger and has almost the same cabin width. And top level became a flop because it's too narrow for a first class cabin by today's standards and all other uses for them make no sense. Top floor existed at all because it was Boeing's entry for a heavy cargo plane competition in which C-…

> it was just about four-engine planes becoming too expensive to run Four engines are also less safe than twin engines. I know it sounds counter-intuitive, but Boeing did the math and made the case.

Isn't that because the twins are designed to a higher standard, due to regulations such as ETOPS? It's not something inherent in two vs four engine designs?

I remember when the US Navy was rejecting single engine aircraft, and the F135 had be be proven literally bulletproof before they would even look at the F-35.

Re: The Boeing 747 begins its final descent

#356

Post by dotancohen »

WalterBright wrote: post #336
scrumper wrote: post #299

Earlier quoted context omitted.

Is this because of something analogous to an expected value calculation? Like the increased probability of failure of a single engine when carrying 4, combined with the lower excess power per engine, means that the safety margin of a 4 engine plane is worse? Or is it something to do with the doubling of the number of critical parts that could fail? I'm struggling to come up with a workable argument why 2 is safer, it…

There's an enormous amount of energy in a jet engine with that spinning turbine. Then there's all the heat, fuel, and fire in it. When that energy lets go, you don't want to be anywhere near it. It's amazing that jet engines work at all! Yet the safety record of the engines is incredibly good.

But twins typically have even larger turbines, no?

Re: The Boeing 747 begins its final descent

#357

Post by WalterBright »

dotancohen wrote: post #356
WalterBright wrote: post #336

Earlier quoted context omitted.

There's an enormous amount of energy in a jet engine with that spinning turbine. Then there's all the heat, fuel, and fire in it. When that energy lets go, you don't want to be anywhere near it. It's amazing that jet engines work at all! Yet the safety record of the engines is incredibly good.

But twins typically have even larger turbines, no?

High bypass fans are newer engine designs, nothing to do with being used in twins.

Though in general, a new engine design necessitates a new wing design, which means a new airplane.

Re: The Boeing 747 begins its final descent

#358

Post by s1artibartfast »

kelnos wrote: post #240
dcrazy wrote: post #141

Earlier quoted context omitted.

They don’t get punished at the polls because people accept, or are at least willing to entertain the implication, that the left wing dislikes America. And what sense does it make to vote for an unpatriotic politician? Would you want to work for a CEO who publicly disdains the company? (Gil Amelio’s infamous quote about steering the sinking Apple ship comes to mind.) As long as the Democratic base insists on caveating…

> what sense does it make to vote for an unpatriotic politician? I really dislike the concept of "patriotism". What does it even mean? I think you'll get different answers if you get different people. If people think that being critical of the US makes someone "unpatriotic", then that's their problem. If that makes a critical politician less electable, so be it. The alternative -- politicians censoring themselves and…

I think it mostly about perspective of history.

For those that were attracted to it, Trump presented the idea that America and it's people are good at good at their core, and this can be brought back.

Those same people view rhetoric from the other side as saying America is and was fundamentally evil and corrupt. They take this personally as a condemnation of them and their family.

Re: The Boeing 747 begins its final descent

#359

Post by WalterBright »

dotancohen wrote: post #355
WalterBright wrote: post #150

Earlier quoted context omitted.

> it was just about four-engine planes becoming too expensive to run Four engines are also less safe than twin engines. I know it sounds counter-intuitive, but Boeing did the math and made the case.

Isn't that because the twins are designed to a higher standard, due to regulations such as ETOPS? It's not something inherent in two vs four engine designs? I remember when the US Navy was rejecting single engine aircraft, and the F135 had be be proven literally bulletproof before they would even look at the F-35.

Engine designs get better and better over time, and tend to become new minimums in safety standards.

Re: The Boeing 747 begins its final descent

#360

Post by boxed »

microgpt wrote: post #324
boxed wrote: post #307

Earlier quoted context omitted.

> Legacy media promotes ideologies consistent with its owners, which is why for instance it downplays bad stuff Israel does and upplays bad stuff Iran does. Partly true, but also mostly wrong. It's all about the business model. Owners doing what you say can only do so much if the business model is based on selling ads and no one gets a salary if they don't attack jews enough for their audience. The claim that Israels…

The business model isn't based on selling ads any more. The primary source of revenue is accepting payment to run or block certain topics

Wow. ENORMOUS citation needed for that one.
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