I meant the 900 as we know it should have never existed and been like the MAX 10 today. (obviously without the MAX improvements)

seahawk wrote:

I meant the 900 as we know it should have never existed and been like the MAX 10 today. (obviously without the MAX improvements)

I'm not sure that was ever an option. The -900 as we know it today already has issues with field performance and stretching it even further with the CFM56 powerplants doesn't seem feasible. The -9 has better range than the -900 due to the Leap's efficiency and some small thrust advantages. Some of that will be traded off for the -10 to become a reality.

It has bad field performance because it was/is angle of rotation limited mostly. Sure a 1000 would have a little less range, but then a A321CEO without Sharklets and ACTs does not fly that far either.

seahawk wrote:

It has bad field performance because it was/is angle of rotation limited mostly. Sure a 1000 would have a little less range, but then a A321CEO without Sharklets and ACTs does not fly that far either.

Often forgotten, but on an A321-200 one ACT really is standard, as now on the 737-10. The one ACT is the range extension between an A321-100 and the A321-200 and the A321-200 has an increased MTOW above the A321-100 to compensate for up to 2 ACT. The second ACT is optional. I assume it is of course possible to order the A321-200 without an ACT.
The range of the 737-900 was also below 3,000nm and the range extension of the ER includes one ACT.

I have a question regarding the design of the 737-10MAX. It is well documented that the 737 series height is restricted by the overwing emergency exit that currently do not require a slide. Raise it more, and Boeing needs to design a slide. This is why Boeing is going ahead with a special designed main landing gear. But after looking at the 757 and A321, I was suddenly asking myself: Why have Boeing not decided to eliminate the overwing exit and have a emergency exit in front of the wing, like the A321 and 757 instead? That way Boeing would not be limited by the overwing emergency exit. They could have increased the height of the plane on the ground, and if they wanted included a bigger engine. They could even have stretched if further. I realize that the new feature on the landing gear raises the plane on rotation. but I am sure this would have been considered?

Oykie wrote:

I have a question regarding the design of the 737-10MAX. It is well documented that the 737 series height is restricted by the overwing emergency exit that currently do not require a slide. Raise it more, and Boeing needs to design a slide. This is why Boeing is going ahead with a special designed main landing gear. But after looking at the 757 and A321, I was suddenly asking myself: Why have Boeing not decided to eliminate the overwing exit and have a emergency exit in front of the wing, like the A321 and 757 instead? That way Boeing would not be limited by the overwing emergency exit. They could have increased the height of the plane on the ground, and if they wanted included a bigger engine. They could even have stretched if further. I realize that the new feature on the landing gear raises the plane on rotation. but I am sure this would have been considered?

I don't think that is as much of an issue as the MLG is, Boeing can't raise the gear because the gear bay is simply not big enough. That's why with the MAX 10 they opted for a telescopic MLG system.

ikolkyo wrote:

Oykie wrote:

I have a question regarding the design of the 737-10MAX. It is well documented that the 737 series height is restricted by the overwing emergency exit that currently do not require a slide. Raise it more, and Boeing needs to design a slide. This is why Boeing is going ahead with a special designed main landing gear. But after looking at the 757 and A321, I was suddenly asking myself: Why have Boeing not decided to eliminate the overwing exit and have a emergency exit in front of the wing, like the A321 and 757 instead? That way Boeing would not be limited by the overwing emergency exit. They could have increased the height of the plane on the ground, and if they wanted included a bigger engine. They could even have stretched if further. I realize that the new feature on the landing gear raises the plane on rotation. but I am sure this would have been considered?

I don't think that is as much of an issue as the MLG is, Boeing can't raise the gear because the gear bay is simply not big enough. That's why with the MAX 10 they opted for a telescopic MLG system.

So this means that raising the MLG, they would need to redo the wingbox? And thats why it will be expensive? Not the overwing exit?

Oykie wrote:

ikolkyo wrote:

Oykie wrote:

I have a question regarding the design of the 737-10MAX. It is well documented that the 737 series height is restricted by the overwing emergency exit that currently do not require a slide. Raise it more, and Boeing needs to design a slide. This is why Boeing is going ahead with a special designed main landing gear. But after looking at the 757 and A321, I was suddenly asking myself: Why have Boeing not decided to eliminate the overwing exit and have a emergency exit in front of the wing, like the A321 and 757 instead? That way Boeing would not be limited by the overwing emergency exit. They could have increased the height of the plane on the ground, and if they wanted included a bigger engine. They could even have stretched if further. I realize that the new feature on the landing gear raises the plane on rotation. but I am sure this would have been considered?

I don't think that is as much of an issue as the MLG is, Boeing can't raise the gear because the gear bay is simply not big enough. That's why with the MAX 10 they opted for a telescopic MLG system.

So this means that raising the MLG, they would need to redo the wingbox? And thats why is will be expensive? Not the overwing exit?

Most likely yes, or they’d have to do a complete redesign of the undercarriage.

Can someone explain to me why they can not use a 2L door about 10 or 12 window frames AFT 1L?

ElroyJetson wrote:

Also, you assume Airbus will eventually make PIP's to the Neo and Boeing will not with the MAX.

Boeing bases their competitive assessment on a 2017 A321 vs a 2021(EIS) 10MAX.
( probably with some derates on the AB side . Just because

Airbus ( actually just the GTF ) has a 3% sfc improvement in the chute for 2019.
Even if both platforms move evenly onwards in PIPs after EIS that also means
that the A321 moves quite a couple of years forward versus a stationary -10MAX.

Oykie wrote:

I have a question regarding the design of the 737-10MAX. It is well documented that the 737 series height is restricted by the overwing emergency exit that currently do not require a slide. Raise it more, and Boeing needs to design a slide. This is why Boeing is going ahead with a special designed main landing gear. But after looking at the 757 and A321, I was suddenly asking myself: Why have Boeing not decided to eliminate the overwing exit and have a emergency exit in front of the wing, like the A321 and 757 instead? That way Boeing would not be limited by the overwing emergency exit. They could have increased the height of the plane on the ground, and if they wanted included a bigger engine. They could even have stretched if further. I realize that the new feature on the landing gear raises the plane on rotation. but I am sure this would have been considered?

Overwing exits cost about 12 inches of cabin space. A floor mounted exit takes 30-48 inches of space. Airbus is copying the 737-9/10 exit layout with their new A321neo exit door configuration because it adds seats.

A taller gear would require the trunnions to move outward. That would change the loads in the wingbox and wing. A longer strut would also weigh more. Exit slides add weight or more floor level exits add weight and sacrifice interior space. A higher fuselage may also require powered cargo doors. All this added weight is increasing fuel burn.

Long range flights get a lot of attention but it is worth mentioning that the average 737NG flight is 900 miles. I would say 90% of airlines want lower fuel burn on their trunk routes between 500 and 1500 miles rather than better field performance at MTOW or longer range. All those compromises to increase the fuselage height have detrimental effects over the majority of routes the plane will fly. Most airlines want lower fuel burn instead of more range. I am sure Boeing has reviewed the options with their customers. Airbus has focused more on the longer range missions, but Boeing appears to want to make a different plane optimized for those missions. It is probably more critical for the MAX to keep OEW down.

Oykie wrote:

IBut after looking at the 757 and A321, I was suddenly asking myself: Why have Boeing not decided to eliminate the overwing exit and have a emergency exit in front of the wing, like the A321 and 757 instead? That way Boeing would not be limited by the overwing emergency exit.

xdlx wrote:

Can someone explain to me why they can not use a 2L door about 10 or 12 window frames AFT 1L?

The 737-8(00), for example. uses Type 1 Passenger doors at L1 and L2 and those are rated for 45 passengers each. The two Type III overwing exits are each rated for 35 passengers. So I am not sure replacing the two Type III overwing exits with an additional Type I would not negatively impact the Exit Limit.

Stitch wrote:

Oykie wrote:

IBut after looking at the 757 and A321, I was suddenly asking myself: Why have Boeing not decided to eliminate the overwing exit and have a emergency exit in front of the wing, like the A321 and 757 instead? That way Boeing would not be limited by the overwing emergency exit.

xdlx wrote:

Can someone explain to me why they can not use a 2L door about 10 or 12 window frames AFT 1L?

The 737-8(00), for example. uses Type 1 Passenger doors at L1 and L2 and those are rated for 45 passengers each. The two Type III overwing exits are each rated for 35 passengers. So I am not sure replacing the two Type III overwing exits with an additional Type I would not negatively impact the Exit Limit.

Also Type 1 doors are heavier, and the 737MAX10 would likely face the same issues as the A321 in which the door would be too close to the engine so that most operators would not be comfortable using it for boarding for fear that a careless gate/ground agent would cancel the flight by knocking the engine.

There is a reason that Airbus is eliminating/phasing out the current A321 layout and replacing the 2L/R doors with overwing exits. Unless you can get an operational benefit from the 2L/R doors (which the A321/737 really can't) then the overwing exit layout is superior.