Why does this exist if Boeing is building 777-9s soon?

Best flying experience in the world, is a seat in the 747 hump. So quiet and cool. All the drinks and snacks you want. Never wait on a toilet. Room to stand up and stretch.

>>1098648
Because it was created on paper and in reality way before the 777X program.

>OP willingly sets foot on any Boeing aircraft

At least with a hanging or intentional OD your family isn't left wondering if you're still alive for weeks on end. Taking a Boeing aircraft is worse than suicidal.

>>1098663
The 747 I went on was loud as fuck up top, it was some Atlas Air charter. The crew made up for it though

>>1098690
well, is better than airbus

>>1098811
Airbus is in a league of their own for safety. How many battery fires have they suffered lately?

>>1098815
How many Airbus aircraft use lithium batteries? Oh right, none. When did Airbus start using composites in the airframe? Oh right, well after Boeing.

>>1098815
> he thinks the safety of an aircraft is dependent on the manufacturer and not the airline responsible for maintaining it

Oh, I see, you're retarded.

>>1098648
Quadjets stil have their advantages. Lack of suitable diversionary runways in the Antarctic means that ETOPS doesn't cover the whole world yet. And 747s do go slightly faster than other aircraft.

But as I said on the trijet thread, what we're likely to see in future is split electrically geared turbofans. Two engines will provide thrust and generate electricity, plus two additional ducted fans will consume electricity to provide extra thrust.

>>1098899
That's a baseless assumption, why would you think that an electric drive would be more efficient or economical than a mechanical one?

>>1098901
It wouldn't. It's stupid. Basic thermodynamics tells us that converting energy from one form to another introduces entropy and losses of efficiency.

>>1098899
ETOPS restrictions have been expanded to cover quads back in a decade or two ago, although the higher engine out speed of 748 mean when all the alternative airports are available, it can fly over all of the Antarctica

Also noteworthy is that, with ETOPS330, the no go zone for twins over Antarctica is still rather large, but due to the sheer distance between different south hemisphere continents, the fuel saving of using twin might be able to beat he shorter hours of quads

>>1098828
>airline responsible for maintaining it
JAL 123 would like to have a word with you

>>1098815
>flight controls of crewmember one and two not linked
>autothrottle doesnt move throttle levers
>protection systems that overrule the pilot have caused a few incidents already
>cockpit design destroys the pilots ability to fly a plane and as soon as shit goes wrong, he is expected to know how to fly again all of a sudden
>whole flight system is basically a "steer with the trim" concept

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Because cargo reasons.

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>>1099051
and then there is this fat bastard

>>1099022
Congratulations, you just inadvertently used statistics to prove yourself wrong. You. Dumb. Cunt.

>>1098901
>why would you think that an electric drive would be more efficient or economical than a mechanical one?
Because it would allow both the compressor and fan to always run at the optimal speed.
Conventional turbofans require them to operate at the same speed. Geared turbofans allow the compressor to run faster, leading to greater overall efficiency despite the mechanical energy losses of the gearbox and its extra weight. Electrically geared turbofans would allow them to run at unrelated speeds. And split electrically geared turbofans would enable more thrust to be produced (or alternatively, greater efficiency for the same amount of thrust due to the lower fan speed requirements) without the weight penalty of full engines.

>>1098930
Most diesel locomotives have electric transmission. Do you think that's stupid as well?

>>1099245
>Most diesel locomotives have electric transmission. Do you think that's stupid as well?
not him, but thats a very different concept. you see, a locomotive is hard connected to the ground, so its very important how good you can dose the power. thats the reason for the diesel-to-electricity conversion. you can dose electrical engines in a much, much better way (no clutch, gearbox isnt half as complicated, etc)
doing this in a plane with a turbofan would be very retarded. you simply dont need it.

if those locomotives were built to accelerate ONCE for like one minute, and then drive at the same speed without any big changes, stops etc. for hours and many thousand miles at a time, they would not convert the diesel to electricity either.

>>1099051
>protection systems that overrule the pilot have caused a few incidents already
Yeah... no.

>>1099255
http://avherald.com/h?article=47d74074

>>1099051
this, so much this.

Also
>Aeroflot Flight 593 (No AP disconnection warning, undocumented obscure feature)
>Shitty side-sticks

>>1098648
We have A320/350(XWB)/380, indeed, boings are ded

>>1099268
Airbus cant keep getting away with it

>>1099338
I dont like airbus because they dont tell the pilot how things work so af447 hapens

>>1099245
A CVT connecting the fan to the engine would be more efficient, and cheaper

There is no need for an electric drive.

>>1099736
What kind of CVT is more efficient than electric but not have reliability problems?

And electric is the only practical way to get one engine to drive multiple fans.

>>1099352
Airbus didn't keep getting away with it. They learned from their mistakes, and the issues that caused the crashes have been fixed.

Boeing used to make better planes than Airbus. But those days are long gone.

But Boeing's far from dead.

>>1099736
>cvt
>efficient
oy vey, there go my sides

File: toroidial cvt.gif (328KB, 400x300px) Image search: [Google]

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>>1099856
>>1099853
>I'm a retard
Must be fun to be you

Toroidal CVTs are 93% efficient and do not have the cost of permanent magnets (PM motor-gen set) if you want to save weight, or the weight of iron rotors (induction motor-gen set) if you want to save money.

Also, an electric motor-gen set would be around 85% efficient for state-of the-art machines.

Even belt-driven CVTs are more efficient than that.

https://web.archive.org/web/20140714215029/http://www.zeroshift.com/pdf/Seamless%20AMT%20Offers%20Efficient%20Alternative%20To%20CVT.pdf

Unless you can convince engine building companies to use superconducting motor-gen sets (which don't exist outside of the lab), your idea wouldn't work in the real world, buddy.

>>1098648
Because it's expensive to replace an entire fleet simultaneously. It's better to phase it out over a long period of time.

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GUISE WHY NOT USE BLEED AIR TO TURN FANO?

>>1099892
Saving weight ultimately saves you money so of course any electric motors on aircraft would use permanent magnets. AIUI these are also more efficient than induction motors. It won't require superconductors for this to become practical, but they will have to do a lot better than 85%.

Belt driven CVTs are certainly not reliable enough for this purpose - I'm not sure about the toroidal CVTs.

>>1099995
Why do you want a variable speed fan anyways?

A plane only climbs and descends for an hour of its flight envelope

Multiple fans aren't more efficient either

The next step in efficiency is the propfan

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>>1100015
b-b-but senpai why not ingest laminar flow?

>>1100039
Because it causes drag and a duct would be better??

>>1100015
>Why do you want a variable speed fan anyways?
Greater engine efficiency.

>A plane only climbs and descends for an hour of its flight envelope
Not quite. It only steeply climbs and descends for an hour o its flight envelope, but it does climb and descend for much of the flight (subject to ATC restrictions).

>Multiple fans aren't more efficient either
Yes they are. Slower fans are more efficient, and having more fans enables them to run slower for the same output.

>The next step in efficiency is the propfan
That's what I used to think. But I can't see how their noise problem could ever be solved, and safety considerations (in the event of engine failure) limit how they could be used.

>>1100158
A large fan can be made to turn slow

>>1100158
What noise problem? Are they any noiser than turbofan or turboprop?

>>1100158
And what safety consideration?

>>1100162

LOL GTF, if you do that might as well go electric multifan when faced with the same dimensional restrictions

>>1100165

Not likely to get stage 3 clearance for noise, which cuts out big markets

>>1100166

No duct to contain fan shrapnel. That's why ducted propfans (really ducted turboprops) are a thing.

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>>1100197
How can't they get stage 3 noise clearance? An-70 already have Stage 3 certification

>>1100198
Turboprop aircrafts are running just fine, and on the event of anything wrong happening to those engines, the duct won't be anywhere near enough to be able to contain anything inside them.

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>>1100214
>Turboprop aircrafts are running just fine,

Scandinavian Airlines Flight 1209
>Five people suffered minor injuries, some from propeller parts entering the cabin and others from the evacuation.

https://blogs.crikey.com.au/planetalking/2017/02/21/essendon-b200-crash-similar-sydney-disaster-2000/

>Like the Essendon crash this morning, which killed all five people on board, the pilot of the Advance flight suffered a catastrophic failure of one of the plane’s two turboprop engines shortly after taking off.

>the duct won't be anywhere near enough to be able to contain anything inside them.
Yeah because modern engines can't be built strong enough to contain turbine failures?

https://www.youtube.com/watch?v=1L02Q11zx0I

>>1100216
>Scandinavian 1209
You mean if the aircraft were using trubofan instead of turboprop, then its landing gear will not have problems?
>b200
You mean jets planes won't experience engine failure?
>Video links demonstrated to be able to contain a failed fan blade
How about for example last year's AA383, or DL1288, or QF32?

>>1100213

I'll give you that, but most propfans are pushers that do have noise problems

>>1100238
>but most propfans are pushers that do have noise problems
Most? What other propfans entered service?

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>>1100235
>Five people suffered minor injuries, some from propeller parts entering the cabin and others from the evacuation.

Read it again slowly anon then think for a few seconds before replying. Actually lemme just spell it for you. If the aircraft had a ducted fan then when the gear collapsed instead of the prop hitting the asphalt and launching it's props through the cabin injuring people, the fan shroud would have hit the asphalt and passengers would have been A-OK!

>You mean jets planes won't experience engine failure?
Maybe I should have quoted another part of the news story

>The pilot of the flight that crashed into the DFO centre building made a Mayday emergency call on the ‘catastrophic’ engine failure before an impact that tore the aircraft into small pieces and sent some wreckage onto the nearby Tullamarine freeway. The crash was witnessed by hundreds of motorists.

>The term ‘catastrophic’ in relation to engine failures generally means an uncontained or explosive disintegration of an engine, and can mean that damage is also done to the fuselage of a plane and control systems. The term ‘catastrophic’ in the context of an emergency call from the plane was used by Victoria Police in briefings. The ATSB investigation will establish the extent to which this may have happened in the DFO crash.

If the prop hadnt damaged the avionics then it would have simply been an engine out event, but because there was no shroud to contain the failure that wasnt the case.

>How about for example last year's AA383, or DL1288, or QF32?
So it's possible for failures to exceed the structural capabilities of the fan shroud BUT THAT DOESNT MEAN THE FAN SHROUD HASNT SAVED LIVES BY CONTAINING MOST FAILURES. Would you rather fly on a plane that might be able to contain a catastrophic engine failure or one that absolutely cannot?

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>>1100240

>>1100263
That's not a propfan

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>>1100265
This is.

>>1100216
>Jet engine
>gasoline

>>1100240

Other than the AN-72 powerplant, none in current service, only developmental engines which had known noise issues. AN-72 is borderline at that, since it was intended for military service.

>>1099249
You're wrong, and have no idea what you're talking about.


Riddle me this: Why are mining trains in the Australian outback still diesel-electric if any of what you said is even remotely correct?

>>1100352
>He doesn't know the power demands on trains vary widely.
There's an over 200% change in tractive effort between notches 1 and 3. Then you have periods of dynamic braking, power braking, idling, and it makes sense to use diesel electrics.

Turbine aircraft operate at 85-90% of peak power output for almost all flight time and are then shutdown if they'll be idling for even moderate amounts of time.

You don't know trains. You don't know planes. You don't even know shit.

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>>1100332
What, this is An-72

>>1100262
lel

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>>1100352
Because unlike a fan moving air, a locomotive is stuck on the ground.

An IC engine produces little torque at low RPM, so a gearbox is needed to multiply it to the wheels. In an aircraft engine, this is not necessary, in fact, most turbofans today have the fan stage separate from the other stages, it's a fluid coupling that slowly spins up through a crude fluid coupling.

You don't seem to have a good understanding of what you're talking about.

>>1100352
>youre wrong, etc, you have no idea blah blah
aight sure, riddle me this then: why the hell arent planes flying with turbine generated electricity then? guess youre a lot smarter than all those stupid engineers who dont know crap about planes and engines.

>>1100263
>>1100266
>>1100265
Turboprop vs propfan is a very nuanced and there is a grey area between the definitinos. Arguably the ti 95 had propfans cause the fan tips were super sonic but the new definition of propfan posits that propfans must have scimitar blades.

There are different agencies defining the difference and it's more a marketing term than anything else because airplane manufacturers wanted to differentiate their new designs from turbo props to appeal to airlines.

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>>1099736
>100 000 kW CVT

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>>1100431
>100 000 kw alternator
good luck fitting it

>>1100458

3600RPM/60Hz AC? Up your game boy...