tjh8402 wrote:

While I get what you're saying, I do think composites are a poor example, as commercial builders are concerned with the economies of scale and mass production, whereas high end military products can be boutique buys and usually involve smaller pieces. It's much less of a production challenge to build composite empennages for F-15s than it is for planes the size of a 787, much less the 777 (recall that supposedly one of Boeings challenges for the 777x was designing an autoclave large enough to make the wings).

I'd also point out that military aircraft made primarily of composite structures are still relatively new. From what I can tell, the first mass produced (so no F117s or F22s) military jets to be made primarily of composites were 4.5 generation planes like the Euro canard twins, and those only entered service this century, even if their first flights were a long time before. As best I can tell, the F-35 is actually the most ordered composite military aircraft and is currently the third most produced behind the Typhoon and F-22 Raptor.

There's also a huge difference between mastering something groundbreaking like composite construction and a mechanism and action that's been in regular use since the second world war.

Perhaps appropriate to this discussion (or perhaps not), but Boeing did composite, folding replacement wings for 200 A-6 Intruders in 1985.

http://www.globalsecurity.org/military/ ... grades.htm says:

The Boeing Company had begun to design a new wing under a Navy contract that was awarded in 1985. With a carbon fiber-epoxy resin torsion box, light alloy control surfaces, and some titanium components, the new wing was much lighter and designed for four times the fatigue life of the existing wing. The composite wing was retrofitted to about 200 A-6E aircraft, which significantly increased the aircraft's capability, safety, and operational life. In addition to becoming a retrofit for the A-6E fleet, the wing was also intended for a new, advanced version of the A-6 to be known as the A-6F. The A-6F was later canceled in the prototype stage when the Navy decided to replace the A-6 fleet with the stealth A-12 aircraft.

They also did the composite wings for the F-22.

I agree the military space is different, but it shows that the basic tech is in place.

mjoelnir wrote:

The folding wingtip will come with the 777-8/9 and there is no reason it should not work. If they do not fold on arrival the frame will need an A380 gate or remote stand. I assume the frame will be able to fly with the tips folded. If the failure rate is similar to inoperable flaps it should be good.
I think there is no reason to worry that Boeing will not solve all technical problems regarding such a system.

Assume, you say? Again, my earlier reference from Boeing's VP for the 77X says a wingtip failure will ground the aircraft.

SomebodyInTLS wrote:

frmrCapCadet wrote:

Ailerons, flaps, slots, slats, extenders, spoilers etc, and all of a sudden another moving part on a wing is a boogie man. Come on, folks.

A flap mechanism failure means the flap stops extending in and out as it should. A wingtip mechanism failure could mean the end of your wing effectively "breaks off"... there's a difference!

A flap extending mechism is mean to operate while the aircraft is in flight.

Anybody hypothesizing that an extended tip may fail in flight (for reasons other than exceeding max design stress loads) is making this far complicated than needed. The tip will be locked in place. In order for it to unfold, the lock would have to be removed, and then the structural element retracted. That's no more likely to happen than that the cabin door locks suddenly retract. Basically it would require a hacking of the plane's control system. Sure, that's a danger. But if they plane's control system is hacked there are much catastrophic things to do than retracting the wing tips (override the flight controls, for example, and cause a structural failure of the tailplane).

"I assume the frame will be able to fly with the tips folded."

I think a more likely scenario would be to remove the tips. The raked wing tips are an MMEL item for the 773ER. If you ding one, it can be removed and the airplane can be dispatched.

Revelation wrote:

mjoelnir wrote:

The folding wingtip will come with the 777-8/9 and there is no reason it should not work. If they do not fold on arrival the frame will need an A380 gate or remote stand. I assume the frame will be able to fly with the tips folded. If the failure rate is similar to inoperable flaps it should be good.
I think there is no reason to worry that Boeing will not solve all technical problems regarding such a system.

Assume, you say? Again, my earlier reference from Boeing's VP for the 77X says a wingtip failure will ground the aircraft.

I'm going to "assume" that he means that the aircraft would remain airworthy in flight if a wingtip becomes loose/unlocked? Not that the aircraft will be taking off with unlocked tips.

PlanesNTrains wrote:

I'm going to "assume" that he means that the aircraft would remain airworthy in flight if a wingtip becomes loose/unlocked? Not that the aircraft will be taking off with unlocked tips.

I agree there is some ambiguity, but I'd resolve it the way Matt is resolving it in #2053. I also think we're making too much of the in-flight failure modes. A6 and F18 wings don't just fold themselves up in flight. The engineering time is spent making sure that such failures are exceedingly rare. There's lots of prior art. We should have every expectation that this will be done correctly. I'd think the main issue would be the transition from folded to unfolded and vice versa, and these transitions happen on the ground, and if a problem happens, you fix it on the ground. Airlines are mostly concerned that these failures can happen at an outstation where they have no technical support, and Boeing is doing the testing so these problems are rare.

Revelation wrote:

I'd think the main issue would be the transition from folded to unfolded and vice versa, and these transitions happen on the ground, and if a problem happens, you fix it on the ground.

This is absolutely correct IMO. The locking mechanism is probably passively safe as well, in addition to requiring some affirmative bad act to even begin the non-structural failure conversation. IIRC structural continuity is provided by "pins" that extend and transfer the load of lift across the structural discontinuity. The amount of pressure applied to those pins under loaded conditions is probably such that they couldn't "slide" inwards even if they weren't locked.

I've been looking for the cite but can't find it... IIRC Boeing plans for 1/10,000 and 1/100,000 failure rate (on the ground) for retraction and deployment, respectively. Thus Boeing expects a retraction failure to occur two or three times over a ~20-30 year airframe life. That eventuality can/will be insured for, and will be a couple decimal points right of statistical significance in a profitability analysis. The Boeing executive saying he wants the mechanism to be "bulletproof" probably reflects that rarity as its goal and its expectation.

re optimality, it should also be noted that, whatever the folding tips' nominal weight delta (1,500lbs IIRC), a large portion of that delta will be canceled out by the mechanism's contribution to wing bending relief. Placing this weight at ~90% of span means it will contribute a lot of bending relief relative to its weight.

Adding mass to the wingtip area is not always favorable, eg 747-8, aeroelstaic loads need to be considered which requires sufficient stiffness to be within the wing to meet these loads.

So let's just go over the mechanism: An electric actuator lowers the tip into place. Once that happens, several pins insert through holes to lock the wingtip into place. Once there is a load on the wingtip (at rotation or just before), the boreholes where the locking pins will be aeroelastically forced against the locking pins and prevent them from moving, even if the actuator fails.

If the actuator fails in flight, the wingtip will remain locked. The failure will not become apparent until the aircraft taxis off the runway and the "up" position is selected.

DocLightning wrote:

SomebodyInTLS wrote:

frmrCapCadet wrote:

Ailerons, flaps, slots, slats, extenders, spoilers etc, and all of a sudden another moving part on a wing is a boogie man. Come on, folks.

A flap mechanism failure means the flap stops extending in and out as it should. A wingtip mechanism failure could mean the end of your wing effectively "breaks off"... there's a difference!

A flap extending mechism is mean to operate while the aircraft is in flight.

I was responding to a suggestion that it would be trivial to design a mechanism for moving wingtips *in flight*.

Matt6461 wrote:

Anybody hypothesizing that an extended tip may fail in flight (for reasons other than exceeding max design stress loads) is making this far complicated than needed. The tip will be locked in place. In order for it to unfold, the lock would have to be removed, and then the structural element retracted. That's no more likely to happen than that the cabin door locks suddenly retract. Basically it would require a hacking of the plane's control system. Sure, that's a danger. But if they plane's control system is hacked there are much catastrophic things to do than retracting the wing tips (override the flight controls, for example, and cause a structural failure of the tailplane).

See my response to DocLightning above - I was only talking about failure in flight since that's a (big) concern when people suggest moving the wingtip in flight.

I'm sure a puny little actuator to move it on the ground, coupled with a chunky fail-safe locking mechanism, is what Boeing have done since that's the smart way to go.

SomebodyInTLS wrote:

I was only talking about failure in flight since that's a (big) concern when people suggest moving the wingtip in flight.

Ah your post makes more sense then. I didn't bother with the idea of wingtip retraction/deployment in flight because that's just silly. The force required to move a ~11ft wingtip would be at least equal to the force on a flap, whose Fowler motion rarely (never?) exceeds 11ft. A flap always requires a tracked arm to allow a big enough lever - no way such a mechanism could fit inside the wing profile.

Revelation wrote:

I also think we're making too much of the in-flight failure modes

How I miss the old emoticons . . . . BIG THUMPS UP THUMPS UP

Agree that in-flight failure modes will not be of much concern. Locking the wingtip in place is a fairly straight forward exercise, engineering wise. And as stated already several times, has been done before.

Bigger concern will be the reliability of the system: airlines -ignoring QR's AAB - these days expect overall aircraft dispatch reliability of around 98.5 - 99.0% at EIS. This introduces a new system, with new dynamics in the airline world that has not been done before on an airliner. Though not unfamiliar in military applications, multi-daily use in airline ops can be a hard/harsh learning field.

(Another (smaller) concern might be weight penalty; every hundred kilograms system weight represent one less paying passenger. Anybody any clues on system weight for the folding mechanism, vs fixed wing?

Oh, and will the folding wingtip be optional? Can one order a regular fixed wingtip, utilizing somewhat better payload/range characteristics?


PW100

PW100 wrote:

Oh, and will the folding wingtip be optional? Can one order a regular fixed wingtip, utilizing somewhat better payload/range characteristics?

Nope. It's standard.

And I expect that reflects operators' wishes.

Remember that with a fixed wingtip this would be a Group VI aircraft, requiring A380 gates. But the operators who have ordered it so far are clearly using it to replace 777-300ERs or (for LH) A340-600s, both Group V airplanes. And most of the best prospects for future orders would also be replacing either 747-400s or 777-300ERs, again Group V airplanes. For all of those operators, a 777 requiring Group VI gates would be a massive disruption to their ground operations.

zeke wrote:

Adding mass to the wingtip area is not always favorable, eg 747-8, aeroelstaic loads need to be considered which requires sufficient stiffness to be within the wing to meet these loads.

'Tis true. At least with the 77X they have the freedom to change any aspect of the design, whereas with the 747 they were constrained by only being able to reloft the airfoil. Of course the 77X team will be well aware of the issues from the 747-8 and can plan accordingly.

DocLightning wrote:

So let's just go over the mechanism: An electric actuator lowers the tip into place. Once that happens, several pins insert through holes to lock the wingtip into place. Once there is a load on the wingtip (at rotation or just before), the boreholes where the locking pins will be aeroelastically forced against the locking pins and prevent them from moving, even if the actuator fails.

If the actuator fails in flight, the wingtip will remain locked. The failure will not become apparent until the aircraft taxis off the runway and the "up" position is selected.

http://aviationweek.com/new-civil-aircr ... ng-wingtip says:

During taxi to the runway at the hold point the crew will command wingtip extension using a geared rotary actuator drive system. “The tip is preloaded into the down stops and four hydraulic LPAs will be commanded to extend the latch pins into the mating bushing stops,” says John Gunderson, lead engineer for folding wingtip certification, safety and test.

The latch pins extend across a clevis arrangement that enables two layers of locking for each pin. “It is belt and suspenders, if you will, but by having a locking mechanism and a secondary locking mechanism behind the latch pin, we keep it from migrating out and can assure ourselves we maintain load path,” says Gunderson. Analysis by Boeing’s flutter engineers “indicates we can lose any one of the four latch pins and we are safe,” he adds. “Flutter is still within acceptable margins.” The locking mechanisms are located within the LPA housing.

So there's a second layer of protection. It's not clear to me at least that you can rely just on aerodynamic forces.

http://aviationweek.com/commercial-avia ... type-tests has a diagram:

Matt6461 wrote:

I didn't bother with the idea of wingtip retraction/deployment in flight because that's just silly. The force required to move a ~11ft wingtip would be at least equal to the force on a flap, whose Fowler motion rarely (never?) exceeds 11ft. A flap always requires a tracked arm to allow a big enough lever - no way such a mechanism could fit inside the wing profile.

Actually the infamous XB-70 Valkyrie had a variant of that idea, and NASA is currently exploring variations on that theme.

http://aviationweek.com/commercial-avia ... ng-folding says:

The Spanwise Adaptive Wing (SAW) concept will be tested on the ground and in flight in a rapid feasibility assessment under NASA’s new Convergent Aeronautics Solutions project. The goal is to show that angling the outboard wing sections up or down can increase yaw stability and control, and reduce rudder size and tail drag.

In addition to raising subsonic aircraft efficiency, wingtips that fold in flight could improve lift and drag on supersonic transports by increasing stability and control authority, and compression lift on the wing. This was done in the 1960s on the North American XB-70 Valkyrie bomber, shrinking the vertical tails and boosting supersonic lift.

The article has a lot more detail, so if you are interested in this thing it might be worth a subscription or a trip to a library that has a subscription.

This is a research topic so perhaps silly to include it in the current generation A/C, but if it allows for smaller rudder size it might be worth it to deal with the complexity.

PW100 wrote:

Revelation wrote:

I also think we're making too much of the in-flight failure modes

How I miss the old emoticons . . . . BIG THUMPS UP THUMPS UP

The internet never forgets... You can dig them up with a little extra work. Just bookmark viewtopic.php?f=12&t=1336137 which has all the details.

Personally I've given up on getting back much if any of the old site. It is what it is, we either have to adapt to it or do something else with our time. I've chosen the former and am glad that many also have, but unfortunately many valuable forum members have chosen the later.

PW100 wrote:

Revelation wrote:

Bigger concern will be the reliability of the system: airlines -ignoring QR's AAB - these days expect overall aircraft dispatch reliability of around 98.5 - 99.0% at EIS. This introduces a new system, with new dynamics in the airline world that has not been done before on an airliner. Though not unfamiliar in military applications, multi-daily use in airline ops can be a hard/harsh learning field.


PW100

Again, it is a single-hinge actuator with a lock. It is orders of magnitude less complicated than flaps or landing gear. It operates under much less stressful conditions than the ailerons (which are under constant actuator control with no locking mechanism, at least for the inboards on a Boeing and the outboards/only ailerons on an Airbus). An aileron failure in flight can crash the airplane rather abruptly and yet we don't wring our hands about this.

If Boeing cannot make it close to 100% reliable, then their engineers are a bunch of morons who don't deserve their degrees.

Revelation wrote:

The internet never forgets... You can dig them up with a little extra work. Just bookmark viewtopic.php?f=12&t=1336137 which has all the details.

Excellent. Bookmarked!

DocLightning wrote:

If Boeing cannot make it close to 100% reliable, then their engineers are a bunch of morons who don't deserve their degrees.

We'll see, just how close to 100% they'll get . . .

astuteman wrote:

I'm tempted to ask "So why are they being used on the 777X?".

The 777 is an all-new wing. (This is also of relevance to the A330 neo comment you had.)

So, if Boeing want to keep a constant wing area (relative to 777 classic), they can shorten the root chord, keep the taper ratio the same and extend the span to make the numbers balance out.

Airbus cannot do that without redesigning the A380 wing* - which is not a small iteration which I interpreted the comments here as alluding to. Yes, something they can, and something I would expect they will (they have patents on moveable wingtips very suited to A380) consider if/when they do an A380 neo.


*same as A330 neo wing. They aren't adjusting the existing wing inboard of, say, the aileron, to the best of my knowledge.

Boeing cutting contract engineers on 777X development:

The Boeing Co. has cut back the number of contract engineers working on 777X design and development. The cuts appear to be limited and unlikely to affect the airplane’s development schedule.

Several dozen contractors were let go in October, and about as many have been told their contracts will not be renewed when they expire in December. The layoffs were confirmed by engineers familiar with the program but not authorized to speak publicly about the 777X.

http://www.heraldnet.com/news/boeing-cu ... velopment/

KarelXWB wrote:

Boeing cutting contract engineers on 777X development...

A good sign, probably, since Boeing often uses contract staff for specialized roles or to backfill areas that need additional staffing quickly. The 747-8 had a number of Japanese contract engineers come over to assist when Boeing pulled internal staff to work on the 787's development when that started to hit the rocks.

Zodiac has unveiled its 777X economy seats.

Due to the wider cabin, seats are now 17.4" instead of 17" on the current 777.

Moreover, revealed Funk, “We’re proud to be the coach class launch customer for the 777X. We are selected and we’ve attended the IPCM [illustrated parts catalogue meeting]; we’re the first out of the gate. So we’re unveiling the seat here, it’s called the Z400. It’s lightweight [and offers] improved living space. Lightweight to the point where it is 10kgs per pax without the IFE equipment. That’s all provisions. Nobody will touch that seat.”

Intriguingly, the Z400 – which RGN tested on the show floor – measures in at an exact 17.4″ seat width, which is precisely the seat width that Boeing said it would be able to offer customers selecting 10-abreast 777X configurations.

https://runwaygirlnetwork.com/2017/04/0 ... aix-day-1/

KarelXWB wrote:

Zodiac has unveiled its 777X economy seats.

Due to the wider cabin, seats are now 17.4" instead of 17" on the current 777.

Moreover, revealed Funk, “We’re proud to be the coach class launch customer for the 777X. We are selected and we’ve attended the IPCM [illustrated parts catalogue meeting]; we’re the first out of the gate. So we’re unveiling the seat here, it’s called the Z400. It’s lightweight [and offers] improved living space. Lightweight to the point where it is 10kgs per pax without the IFE equipment. That’s all provisions. Nobody will touch that seat.”

Intriguingly, the Z400 – which RGN tested on the show floor – measures in at an exact 17.4″ seat width, which is precisely the seat width that Boeing said it would be able to offer customers selecting 10-abreast 777X configurations.

https://runwaygirlnetwork.com/2017/04/0 ... aix-day-1/

Wait a min - someone promised 18 inch seats in 777-9X!

anrec80 wrote:

Wait a min - someone promised 18 inch seats in 777-9X!

Not really. All Boeing said was "it could be done" but never promised to make it default. It would require smaller aisles and/or smaller arm rests.

KarelXWB wrote:

Zodiac has unveiled its 777X economy seats.

Due to the wider cabin, seats are now 17.4" instead of 17" on the current 777.

Moreover, revealed Funk, “We’re proud to be the coach class launch customer for the 777X. We are selected and we’ve attended the IPCM [illustrated parts catalogue meeting]; we’re the first out of the gate. So we’re unveiling the seat here, it’s called the Z400. It’s lightweight [and offers] improved living space. Lightweight to the point where it is 10kgs per pax without the IFE equipment. That’s all provisions. Nobody will touch that seat.”

Intriguingly, the Z400 – which RGN tested on the show floor – measures in at an exact 17.4″ seat width, which is precisely the seat width that Boeing said it would be able to offer customers selecting 10-abreast 777X configurations.

https://runwaygirlnetwork.com/2017/04/0 ... aix-day-1/

Interesting, the ACAP was also released within the last week. According to that, seat width would be 17.2 with 18 inch aisles (basically the same as the 787 9 abreast layout). This with this seat at 17.4, aisles would remain at 17 inches like the previous configuration.

http://www.boeing.com/assets/pdf/commer ... Prelim.pdf

anrec80 wrote:

Wait a min - someone promised 18 inch seats in 777-9X!

Can still be done using 1.5 inch armrests. The seat being shown is using a 2 inch armrests. It looks like Boeing doesn't want to go the "Airbus way" and start thinning armrests.

817Dreamliiner wrote:

Interesting, the ACAP was also released within the last week. According to that, seat width would be 17.2 with 18 inch aisles (basically the same as the 787 9 abreast layout). This with this seat at 17.4, aisles would remain at 17 inches like the previous configuration.

I suppose Boeing wanted to be consistent in the airport planning document. Seat vendors have a bit wiggle room and can choose the width; it's clear that Zodiac aims for 17.4" seats and 17" aisles, while other vendors may aim for 17.2" seats and 18" aisles.

10 kgs per seat! That is a massive gain over the old 23 kg seats. I know sub 20 kg seats have become normal, but 10 kgs is really a new benchmark for other seat manufacturers to aspire to.

How is the facility shaping up? Have any long lead time parts started manufacturing yet??

travelhound wrote:

10 kgs per seat! That is a massive gain over the old 23 kg seats. I know sub 20 kg seats have become normal, but 10 kgs is really a new benchmark for other seat manufacturers to aspire to.

Not a big schokker, the current CL3710 long-haul seat is already 12 kg.

KarelXWB wrote:

Zodiac has unveiled its 777X economy seats.

Due to the wider cabin, seats are now 17.4" instead of 17" on the current 777.

Moreover, revealed Funk, “We’re proud to be the coach class launch customer for the 777X. We are selected and we’ve attended the IPCM [illustrated parts catalogue meeting]; we’re the first out of the gate. So we’re unveiling the seat here, it’s called the Z400. It’s lightweight [and offers] improved living space. Lightweight to the point where it is 10kgs per pax without the IFE equipment. That’s all provisions. Nobody will touch that seat.”

Intriguingly, the Z400 – which RGN tested on the show floor – measures in at an exact 17.4″ seat width, which is precisely the seat width that Boeing said it would be able to offer customers selecting 10-abreast 777X configurations.

https://runwaygirlnetwork.com/2017/04/0 ... aix-day-1/

As expected. Thanks for the update!

KarelXWB wrote:

[ Not a big schokker, the current CL3710 long-haul seat is already 12 kg.

Do you have any weights on currently offered J and F seats? Am I right in understanding that modern IFE systems have done away with under seat boxes and consist of back of seat screens wired to a central location? Perhaps 2 to 3 kg per seat?

pugman211 wrote:

How is the facility shaping up? Have any long lead time parts started manufacturing yet??

Since it's Zodiac we are talking about expect delays...

I think all they are is little single board computers essentially built in behind the screen. The seat is provided with network and power cables.

817Dreamliiner wrote:

Interesting, the ACAP was also released within the last week.

Thanks! Didn't see this.

The ACAP gives a preliminary MZFW of 562,000 lbs.
That should put to rest past discussions alleging that the 777-9's payload would be drastically less than the 77W. Aspire Aviation had reported this "fact," but Aspire is/was often dumb.
Assuming an OEW of ~407,000lbs, payload will be around what the 77W could lift.

I think some folks are making too much of the folding wing tip issue.

First, human beings are stupid and therefore will always find a way to screw up. That's why the plane will be certified to take off in an emergency with the tips folded. I'm talking about an issue or problem on takeoff where the locking mechanism fails or the trained bears up front don't heed the cockpit warnings. When I say certified I don't mean that it will be a standard procedure, just that if something fails the plane would not simply auger in. There will be procedures to abort the takeoff (just as here are now) or take off and go around and land. I don't see how this would be anymore dangerous than losing an engine on takeoff. Neither situation is ideal, but neither is definitely fatal, either.

Second, the plane will be able to continue flying if the locking mechanism fails in flight. Obviously, this will alter it's flight characteristics, but it will happen eventually. Something will break, or some doofus will forget to install a locking pin or something... Murphy's Law, remember? The FAA won't certify a plane that can't lose it's folding wingtips and still divert. The rest of the wing will generate enough lift to get it to the nearest suitable airfield.

Finally, folded wings flight, while not ideal, has happened. The F-8 Crusader flew with folded wings. Heck, it took off and landed with folded wings. So did the F-4, reportedly, and I'm sure there were others. Granted, those were high power military planes, but the principal is the same, and given the F-4's truck like flying characteristics, all the more impressive.

Bottom line, Boeing knows what it's doing in this regard. They have oodles of experience, and even if the mechanism fails the plane will be able to divert, abort, or go around safely.

Bob

The Concorde moved the entire nose of the plane up. In 30 odd years, the concorde never had major problems with the nose. There is no problem with folding wingtips, not when an aircraft has thousands of other moving parts.

Matt6461 wrote:

Assuming an OEW of ~407,000lbs, payload will be around what the 77W could lift.

The aircraft is larger though, sounds like the 777-9 will sacrifice cargo capabilities for additional passengers.

But if the payload is the same - it won't have to carry as much fuel for the same mission which will allow for the mass of the extra people and there luggage.

KarelXWB wrote:

The aircraft is larger though, sounds like the 777-9 will sacrifice cargo capabilities for additional passengers.

IMO the payload capabilities of most in-production aircraft are too high - at least for longhaulers. By this I mean max payload only, not payload/range capability (different argument).

For example, the 77W's 160,000lb payload leaves room for ~83,000lbs in the belly after boarding 350 pax.
Assuming each LD3 holds bags for 26 pax, that leave ~31 LD3's free in the belly.
At a cargo density of 10.6 lb/ft3, and 135ft3 per LD3, you have physical space for only ~44,000 lbs of cargo.
Cargo tares and other miscellaneous items wouldn't make up the ~40,000lb gap.
To hit the payload max, you really need 400+ pax with few bags, very dense cargo, and/or a very heavy BFE configuration.

Same goes for the A380 and its ~220,000lb payload. Even assuming very heavy BFE such as with EK's showers/plumbing, it's hard to see how you ever bump against the max payload limit.

The high payload limits seem to account for max-density, max-cargo usages.
The OEM's are probably beginning to see that very few customers will ever adopt these usages.

That high payload, remember, is not free.
Each additional ton of max payload increases the critical bending moment and therefore determines the amount of reinforcement needed in the wings and fuselage.
Boeing probably saved a couple tons of weight by not increasing the -9's payload in line with capacity.

morrisond wrote:

But if the payload is the same - it won't have to carry as much fuel for the same mission which will allow for the mass of the extra people and there luggage.

MZFW is the maximum weight of payload allowed after which all additional weight must be in the form of fuel. You can't trade that unused weight bookmarked for fuel with payload.

817Dreamliiner wrote:

Can still be done using 1.5 inch armrests. The seat being shown is using a 2 inch armrests. It looks like Boeing doesn't want to go the "Airbus way" and start thinning armrests.

Incorrect. With 1.5" armrests and 18" aisles the seat width is 17.86" in the window row and 17.82" in the middle row not 18". These numbers from Boeing ACAP.

Strato2 wrote:

817Dreamliiner wrote:

Can still be done using 1.5 inch armrests. The seat being shown is using a 2 inch armrests. It looks like Boeing doesn't want to go the "Airbus way" and start thinning armrests.

Incorrect. With 1.5" armrests and 18" aisles the seat width is 17.86" in the window row and 17.82" in the middle row not 18". These numbers from Boeing ACAP.

You can do 1.5" armrests and 18" seats with 17" aisles. You can see that it will work out to be slightly less in total than the total number in the ACAP (233.5" versus 234"), so therefore I am correct.

Aptivaboy wrote:

I think some folks are making too much of the folding wing tip issue.

First, human beings are stupid and therefore will always find a way to screw up. That's why the plane will be certified to take off in an emergency with the tips folded. I'm talking about an issue or problem on takeoff where the locking mechanism fails or the trained bears up front don't heed the cockpit warnings. When I say certified I don't mean that it will be a standard procedure, just that if something fails the plane would not simply auger in. There will be procedures to abort the takeoff (just as here are now) or take off and go around and land. I don't see how this would be anymore dangerous than losing an engine on takeoff. Neither situation is ideal, but neither is definitely fatal, either.

Second, the plane will be able to continue flying if the locking mechanism fails in flight. Obviously, this will alter it's flight characteristics, but it will happen eventually. Something will break, or some doofus will forget to install a locking pin or something... Murphy's Law, remember? The FAA won't certify a plane that can't lose it's folding wingtips and still divert. The rest of the wing will generate enough lift to get it to the nearest suitable airfield.

Finally, folded wings flight, while not ideal, has happened. The F-8 Crusader flew with folded wings. Heck, it took off and landed with folded wings. So did the F-4, reportedly, and I'm sure there were others. Granted, those were high power military planes, but the principal is the same, and given the F-4's truck like flying characteristics, all the more impressive.

Bottom line, Boeing knows what it's doing in this regard. They have oodles of experience, and even if the mechanism fails the plane will be able to divert, abort, or go around safely.

Bob

Military planes really aren't the best examples to refer to in this matter as their bodies generate enough lift so they don't really need wings at all in flight. I do agree with what you're saying though, that it will be able to fly with the tip(s) folded and it'll be safe as well, but there really isn't much to compare it to.

link to the video of the Israeli F-15 accident. http://www.youtube.com/watch?v=M359poNjvVA

Strato2 wrote:

817Dreamliiner wrote:

Can still be done using 1.5 inch armrests. The seat being shown is using a 2 inch armrests. It looks like Boeing doesn't want to go the "Airbus way" and start thinning armrests.

Incorrect. With 1.5" armrests and 18" aisles the seat width is 17.86" in the window row and 17.82" in the middle row not 18". These numbers from Boeing ACAP.

Then go to 17" aisles instead of 18" and take those two inches and disperse it across the 10 seats

Note that Zodiac's seats pictured are with 17" aisles and not 18". That is how they got 17.4" when the Boeing ACAP says it should be 17.2", Boeing is using 18" aisles. 10Y 77Ws have 17" aisles. So right now Boeing is using the extra space of the 77X to give both 0.2 wider seats and 1" wider aisles for the ACAP, with the same 2" armrests. Airlines may decide to use the extra space differently.

Military planes really aren't the best examples to refer to in this matter as their bodies generate enough lift so they don't really need wings at all in flight. I do agree with what you're saying though, that it will be able to fly with the tip(s) folded and it'll be safe as well, but there really isn't much to compare it to.

Not trying to be argumentative, but I think we can make some general comparisons. Neither the F-8 nor the F-4 were lifting bodies, nor blended wing/fuselage frames like the F-15. They were closer to the tubes with wings stuck on that we currently fly in today than the F-15, especially the Crusader. In fact, if you'll check out some planform photos of them you'll be amazed at the percentage of lifting area they lost in folded wings flight and were still able to safely if sluggishly fly and recover. The fact that they could do it, says a lot about the reserves of lift built into modern wings, even cruder ones from the fifties when both planes were designed, and the F-4 was hardly a wing loading superstar. Now, back on point toss in today's supercritical wings, fly by wire and massive thrustbusters like the GE90 and it's successors and it won't be that huge of a deal, assuming the wing tips don't actually come off and hit the horizontal stabilizers.

KarelXWB wrote:

Zodiac has unveiled its 777X economy seats. Due to the wider cabin, seats are now 17.4" instead of 17" on the current 777.

Which is what the 747 family offered for decades with nobody screaming about being . In fact, the folks carping about the 777 at 10-abreast pointed to how much more comfortable the 747 at 10-abreast was so if they're still complaining it's not acceptable...

817Dreamliiner wrote:

Strato2 wrote:

817Dreamliiner wrote:

Can still be done using 1.5 inch armrests. The seat being shown is using a 2 inch armrests. It looks like Boeing doesn't want to go the "Airbus way" and start thinning armrests.

Incorrect. With 1.5" armrests and 18" aisles the seat width is 17.86" in the window row and 17.82" in the middle row not 18". These numbers from Boeing ACAP.

You can do 1.5" armrests and 18" seats with 17" aisles. You can see that it will work out to be slightly less in total than the total number in the ACAP (233.5" versus 234"), so therefore I am correct.

You are not correct as you didn't say anything about aisles in your previous post. Therefore we must assume you meant 18" aisle which is what is specified in the Boeing ACAP and which is what Airbus also uses in its calculations. You made a big hoopla about Airbus thinning the armrest so pretty ironical when you now start thinning the 777X aisle to fit your argument. BTW With 1.5" armrests A350 actually has 18.03" of space for a seat so the realworld difference with everything else equal is 0.2" between the A350(9ab) and 777X(10ab) with A350 having always wider seats.

Strato2 wrote:

817Dreamliiner wrote:

Strato2 wrote:

Incorrect. With 1.5" armrests and 18" aisles the seat width is 17.86" in the window row and 17.82" in the middle row not 18". These numbers from Boeing ACAP.

You can do 1.5" armrests and 18" seats with 17" aisles. You can see that it will work out to be slightly less in total than the total number in the ACAP (233.5" versus 234"), so therefore I am correct.

You are not correct as you didn't say anything about aisles in your previous post. Therefore we must assume you meant 18" aisle which is what is specified in the Boeing ACAP and which is what Airbus also uses in its calculations. You made a big hoopla about Airbus thinning the armrest so pretty ironical when you now start thinning the 777X aisle to fit your argument. BTW With 1.5" armrests A350 actually has 18.03" of space for a seat so the realworld difference with everything else equal is 0.2" between the A350(9ab) and 777X(10ab) with A350 having always wider seats.

I have no dog in the fight, but if you ask me, 17.86" and 18.00" are pretty much the same thing. My wife has never said "I really want to take another .14" off my waist to fit into those new pants". To be fair, she looks great - I'm the one that needs to lose the inches. Regardless, I think it's fair for a passenger to see 17.86" and 18.00" the same. If the manufacturers or fanboys want to parse it, knock yourselves out.

Strato2 wrote:

817Dreamliiner wrote:

Strato2 wrote:

Incorrect. With 1.5" armrests and 18" aisles the seat width is 17.86" in the window row and 17.82" in the middle row not 18". These numbers from Boeing ACAP.

You can do 1.5" armrests and 18" seats with 17" aisles. You can see that it will work out to be slightly less in total than the total number in the ACAP (233.5" versus 234"), so therefore I am correct.

You are not correct as you didn't say anything about aisles in your previous post. Therefore we must assume you meant 18" aisle which is what is specified in the Boeing ACAP and which is what Airbus also uses in its calculations. You made a big hoopla about Airbus thinning the armrest so pretty ironical when you now start thinning the 777X aisle to fit your argument. BTW With 1.5" armrests A350 actually has 18.03" of space for a seat so the realworld difference with everything else equal is 0.2" between the A350(9ab) and 777X(10ab) with A350 having always wider seats.

I said that in reference to the seat shown by karel, which is 17.4" which can only fit with 17" aisles. If you want to do the math, you will see that it works out to be the same as the cross section in the ACAP, 234". That same seat with 1.5" armrest would be 18.05", so you're wrong on that particular aspect.

In the March 2017 ACAP, the 777-9 OEW is TBD, presumably To Be Disclosed? In the absence of this important number, presumably we have to rely on working back from the Payload Range or other data? How accurate are these calculated OEW numbers?