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-   -   The Biggest Jet Engines in History Are Finally Ready to Power Boeing's Biggest Plane (https://www.pprune.org/rumours-news/616933-biggest-jet-engines-history-finally-ready-power-boeings-biggest-plane.html)

CurtainTwitcher 5th Jan 2019 06:20


Originally Posted by porch monkey (Post 10352236)
EEngr. Great picture. What a magnificent machine. I've never seen that photo before. You got any more?

Try this google reverse image search link HERE for more photo's.

HowardB 5th Jan 2019 08:09

Maybe the drawing FlyXKsa posted is a hint from Boeing about the design of their new 797. It is to be powered by a de-rated single GE90 built into the fuselage..... after all if Cirus can do it, why not Boeing? We can look forward to the videos of their giant airframe parachute system being tested.
Happy New Year to all Ppruners from a member of the SLF team

DaveReidUK 5th Jan 2019 08:14


Originally Posted by Photonic (Post 10352174)
C'mon, the USN was flying fighters with folding wings off carriers in WW2. I think they've probably worked out the kinks by now!

Well most of the time. :O

https://cimg7.ibsrv.net/gimg/pprune....ec87e6c776.jpg

BluSdUp 5th Jan 2019 10:02

Folding wings
 
Wiffy says ": Ah , just another thing that can go wrong!"
And she is an Domestic Engineer.

Oh and Boeing, do us a favor , connect it to the TakeOff Config Warning
Just in case.
Gone fishing
Watching the Eagles
Cpt B

cattletruck 5th Jan 2019 10:43

The original B777 prototype had folding wings tips. I believe it was meant to be an optional extra, not sure if anyone ordered it. I guess it will just serve to further complicate all that line graffiti around the terminal area.

And yes, that is an impressively big engine.

Una Due Tfc 5th Jan 2019 10:53

Slightly less powerful (and far more efficient) than it's predecessor is it not?

hans brinker 5th Jan 2019 14:36


Originally Posted by Vernand (Post 10352187)
Awesome engine, its so big it probably creates lift at certain angles.


mcas......................

GS-Alpha 5th Jan 2019 19:47


Ahhh yes, the folding wingtip version https://www.pprune.org/images/smilies/eek.gif

I don't care what the brochure says, that alone will keep me off the jet. At least the 787 gets there, even if it is with a numbum.
Better avoid anything with reverse thrust too, just to be sure.

tdracer 5th Jan 2019 19:55


Originally Posted by Una Due Tfc (Post 10352499)
Slightly less powerful (and far more efficient) than it's predecessor is it not?

Yes, around 105k lbs. max thrust vs. around 115k for the GE90-115B. In spite of the larger aircraft, they think the improved fuel burn will mean carrying less fuel and a lower MTO than the -300ER for the same range. Hence less Max TO thrust required.

Cattletruck, the original 777 had folding wings as an option, but no one ever ordered it and no flyable 777s were ever built with the feature. I suspect there were some structural provisions in the early build wings, but those were quietly removed to save weight as it became apparent no one was going to order the folding wings. The original folding wing was far more complex than what is being used for the 777X - the original folded where there were still flaps and such (and hence hydraulics) outboard of the fold point. On the 777X, the folding portion is outboard of any movable aerodynamic surfaces - hence no hydraulics outboard, just some electrical wiring for the collision lights and such.
IIRC, the original 777 folding wing was to get the 777 into the same gate size as a 767. The 777X folding wing is simply to get the X into the same gate size as the 777-300ER.

theNotoriousPIC 6th Jan 2019 10:55


Originally Posted by tdracer (Post 10352866)
Yes, around 105k lbs. max thrust vs. around 115k for the GE90-115B. In spite of the larger aircraft, they think the improved fuel burn will mean carrying less fuel and a lower MTO than the -300ER for the same range. Hence less Max TO thrust required.

That is fascinating, and a true testament to progress. It's not about making it bigger, but making it better.

ATCO1962 6th Jan 2019 16:35

How could Popular Mechanics get their base info about the 777X so wrong? This aircraft isn't even close to Boeing's biggest aircraft.

casablanca 6th Jan 2019 17:19


Originally Posted by ATCO1962 (Post 10353508)
How could Popular Mechanics get their base info about the 777X so wrong? This aircraft isn't even close to Boeing's biggest aircraft.

I understand it too mean the biggest engines( not biggest jet)....but then reread and it says biggest( maybe longest but not biggest)

DaveReidUK 6th Jan 2019 17:39


Originally Posted by casablanca (Post 10353551)
I understand it too mean the biggest engines (not biggest jet)....but then reread and it says biggest (maybe longest but not biggest)

To be fair, the article does qualify the statement by saying subsequently that it's Boeing's largest twin, which it obviously is.

That said, the 777X's length, span and (with the exception of the 747SP) height are all greater than any previous Boeing jet airliner.

IBMJunkman 6th Jan 2019 18:18

What speed are the fan blade tips traveling at full power?

NWA SLF 6th Jan 2019 18:20

tdracer - I see the max takeoff weights are the same for 777-300ER and 777-9. I didn't find published takeoff distance under standard conditions for the 777-9 - I assume they need to be confirmed by testing. With the same max weight and 10,000 pounds less thrust, shouldn't the takeoff distance be longer or does the large wing factor in with reduced takeoff speed? Boeing's video showing the first engine being mounted shows an airframe lacking a lot of missing parts. As a Boeing stockholder should I be concerned?

lomapaseo 6th Jan 2019 19:25


Boeing's video showing the first engine being mounted shows an airframe lacking a lot of missing parts. As a Boeing stockholder should I be concerned?
NO, only as a passenger on the first flight

Think of it as more of a progress photo to calm the investors

DaveReidUK 6th Jan 2019 19:32


Originally Posted by IBMJunkman (Post 10353583)
What speed are the fan blade tips traveling at full power?

We're told that the GE9x has a higher tip speed than its predecessors, thanks to the redesigned blades and lower blade count.

Assuming a typical 2400 rpm at 100% N1, the tips of a 134" fan will be travelling at around 430 m/s (apologies for the mixed units).

WHBM 6th Jan 2019 19:50


Originally Posted by tdracer (Post 10352866)
the original 777 had folding wings as an option, but no one ever ordered it and no flyable 777s were ever built with the feature. I suspect there were some structural provisions in the early build wings, but those were quietly removed to save weight as it became apparent no one was going to order the folding wings....IIRC, the original 777 folding wing was to get the 777 into the same gate size as a 767.

As I recall it from the early 1990s, the original 777 folding wingtips were specifically to get it into the domestic gates at Chicago O'Hare. Possibly elsewhere but that was the critical design driver. The idea was to fit where the DC-10/L-1011 fitted, on domestic flights from there to California, Florida, etc, of American, United, TWA and the others. The gates had been arranged to just about fit these types when originally introduced.

In just a few years that followed widebodies disappeared altogether from US domestic flights, initially from mid-Continent points like Chicago, and afterwards even from coast-to-coast flights. I don't think any 777s were ever configured and deployed wholly on US domestic flights. The requirements and mission of aircraft types do change notably over time, and particular features for particular markets do have a habit of not working out long term.

IBMJunkman 7th Jan 2019 11:21


Originally Posted by DaveReidUK (Post 10353658)
We're told that the GE9x has a higher tip speed than its predecessors, thanks to the redesigned blades and lower blade count.

Assuming a typical 2400 rpm at 100% N1, the tips of a 134" fan will be travelling at around 430 m/s (apologies for the mixed units).

So 961 mph or 1.24 Mach. That be fast!

Buster15 7th Jan 2019 12:36


Originally Posted by IBMJunkman (Post 10353583)
What speed are the fan blade tips traveling at full power?

Less than sonic you can be sure of that.


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