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B737 Vs B757 Cockpit/Nose

Mon Sep 02, 2013 7:32 pm

If the 737 and 757 fuselage (height, width) are identical, as has been discussed on here many times... ie, a Boeing narrow body is a Boeing narrow body... why did Boeing alter the design of the cockpit/nose on the 757 (vs the 737)? It's been stated that the 737 cockpit is cramped and the 757 cockpit is more roomy. Why did Boeing not adopt and incorporate the 757 cockpit/nose design for the next gen 737s? Would a change have significantly impacted the aerodynamics of the 737?
 
DualQual
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RE: B737 Vs B757 Cockpit/Nose

Mon Sep 02, 2013 7:34 pm

Boeing originally wanted to put the 757 nose on the 737NG. It would have not been a common type though with be Classics. I understand that SWA, as the launch customer, did not like that idea.
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L0VE2FLY
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RE: B737 Vs B757 Cockpit/Nose

Mon Sep 02, 2013 7:43 pm

The 737 & 757 are totally different aircrafts, they just happen to have the same fuselage cross section. Boeing did the right thing, nothing defines a 737 like its signature nose.
 
DualQual
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RE: B737 Vs B757 Cockpit/Nose

Mon Sep 02, 2013 8:33 pm

Quoting L0VE2FLY (Reply 2):

You've clearly never stowed a bag or bashed your head on the overhead in that cockpit     
There's no known cure for stupid
 
OldAeroGuy
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RE: B737 Vs B757 Cockpit/Nose

Mon Sep 02, 2013 9:07 pm

Quoting questions (Thread starter):
why did Boeing alter the design of the cockpit/nose on the 757

To accommodate the 767 flight deck and gain a common type rating.
Airplane design is easy, the difficulty is getting them to fly - Barnes Wallis
 
flyingcello
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RE: B737 Vs B757 Cockpit/Nose

Mon Sep 02, 2013 9:32 pm

Quoting OldAeroGuy (Reply 4):
To accommodate the 767 flight deck and gain a common type rating.

This is my understanding too...the innards of the 757 and 767 cockpits are the same. Difference is you step down into the 757 cockpit, and up into the 767 I think...

The 757 nose, for me, is still one of the best looking out there...although the 737, without eyebrows, looks good too. Noisy though from what pilots say.
 
OldAeroGuy
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RE: B737 Vs B757 Cockpit/Nose

Tue Sep 03, 2013 12:16 am

Quoting flyingcello (Reply 5):
Difference is you step down into the 757 cockpit, and up into the 767 I think...

Correct.
Airplane design is easy, the difficulty is getting them to fly - Barnes Wallis
 
Viscount724
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RE: B737 Vs B757 Cockpit/Nose

Tue Sep 03, 2013 12:26 am

Quoting questions (Thread starter):
If the 737 and 757 fuselage (height, width) are identical, as has been discussed on here many times... ie, a Boeing narrow body is a Boeing narrow body..

Width is the same, not the height. The 707 also had a deeper fuselage dimension vertically than the 727/737 although the width was the same.
 
Mender
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RE: B737 Vs B757 Cockpit/Nose

Tue Sep 03, 2013 9:35 am

It's surprising how many people don't realise the 757 fuselage has a difference in cross sectional height fore and aft of the wing box.

Quoting flyingcello (Reply 5):
This is my understanding too...the innards of the 757 and 767 cockpits are the same. Difference is you step down into the 757 cockpit, and up into the 767 I think...

You sit 'up' in the bigger diameter fuselage and lower in the smaller fuselage to give the pilots the same perspective when they are sat in the pilots seat. IE. it's the space behind you that is bigger in the 767. From the seat looking forwards they both appear to be the same size.
 
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CALTECH
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RE: B737 Vs B757 Cockpit/Nose

Tue Sep 03, 2013 9:33 pm

Quoting Viscount724 (Reply 7):
Width is the same, not the height. The 707 also had a deeper fuselage dimension vertically than the 727/737 although the width was the same.

Actually, it is the other way around, and only in the aft cargo compartment where the 707 is actually the smaller dimension for fuselage height. The 727, 737 and 757 have a taller aft cargo compartment by 11.96 inches. The passenger cabins are pretty much all the same except for interior fittings. You can find all of the dimensions under Aircraft Description in the following link.

http://www.boeing.com/boeing/commercial/airports/plan_manuals.page

Quoting Mender (Reply 8):
It's surprising how many people don't realise the 757 fuselage has a difference in cross sectional height fore and aft of the wing box.

Seems the 727 and 737 also share this difference which increases the height of the aft cargo compartments.
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flyingcello
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RE: B737 Vs B757 Cockpit/Nose

Tue Sep 03, 2013 9:49 pm

Quoting Mender (Reply 8):
It's surprising how many people don't realise the 757 fuselage has a difference in cross sectional height fore and aft of the wing box.

Mender, please explain! Are you saying that the fuselage height varies between the fore and aft fuselage? Why would Boeing do this? Surely a uniform cross section is much more sensible for all sorts of reasons...

...or am I misreading your comment?
 
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CALTECH
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RE: B737 Vs B757 Cockpit/Nose

Tue Sep 03, 2013 10:46 pm

Quoting flyingcello (Reply 10):
Mender, please explain! Are you saying that the fuselage height varies between the fore and aft fuselage? Why would Boeing do this? Surely a uniform cross section is much more sensible for all sorts of reasons...

...or am I misreading your comment?

This might help,...

Boeing 707

http://i297.photobucket.com/albums/mm233/CALTECHphoto/scan5707_zps3c7cd56d.jpg

727

http://i297.photobucket.com/albums/mm233/CALTECHphoto/scan0001_zps490b0c58.jpg

737

http://i297.photobucket.com/albums/mm233/CALTECHphoto/scan0002_zpsbf0f2050.jpg

757

http://i297.photobucket.com/albums/mm233/CALTECHphoto/scan0003_zpsbd1f8857.jpg

I will measure the cabin width at shoulder and head level between the A-320 and Boeing 737/757 to see what the actual difference is.
UNITED Would Be Nice
 
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DL_Mech
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RE: B737 Vs B757 Cockpit/Nose

Tue Sep 03, 2013 11:32 pm

Quoting flyingcello (Reply 10):
Mender, please explain! Are you saying that the fuselage height varies between the fore and aft fuselage?

It is easily seen here:


View Large View Medium
Click here for bigger photo!

Photo © Serge Bailleul - AirTeamImages


View Large View Medium
Click here for bigger photo!

Photo © M.J. Scanlon Photography



Compared to the 707:


View Large View Medium
Click here for bigger photo!

Photo © Peter Seemann



[Edited 2013-09-03 16:53:58]
This plane is built to withstand anything... except a bad pilot.
 
OldAeroGuy
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RE: B737 Vs B757 Cockpit/Nose

Tue Sep 03, 2013 11:53 pm

After the 757 was certified, I asked Jack Wimpress, the 757 Chief Technical Engineer what he thought the biggest error was on the development program.

His answer was not having the same lower lobe for the whole airplane. Early wind tunnel data indicated the deeper forward lower lobe had an unacceptable impact on directional stability for some conditions. Later testing showed there was no issue but it was too late to change the airplane production plan.
Airplane design is easy, the difficulty is getting them to fly - Barnes Wallis
 
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CALTECH
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RE: B737 Vs B757 Cockpit/Nose

Wed Sep 04, 2013 1:10 am

Quoting OldAeroGuy (Reply 13):
After the 757 was certified, I asked Jack Wimpress, the 757 Chief Technical Engineer what he thought the biggest error was on the development program.

His answer was not having the same lower lobe for the whole airplane. Early wind tunnel data indicated the deeper forward lower lobe had an unacceptable impact on directional stability for some conditions. Later testing showed there was no issue but it was too late to change the airplane production plan.

Did they find the same issue for the 727/737 programs ? They too have the deeper lower lobe in the aft cargo compartments.

Comparision of the 737/757 side views,

http://i4.photobucket.com/albums/y120/Aeroweanie/Sideview.jpg

A modified photo of a concept 757 with a 737 nose,

UNITED Would Be Nice
 
Viscount724
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RE: B737 Vs B757 Cockpit/Nose

Wed Sep 04, 2013 1:53 am

Quoting CALTECH (Reply 9):
Quoting Viscount724 (Reply 7):
Width is the same, not the height. The 707 also had a deeper fuselage dimension vertically than the 727/737 although the width was the same.

Actually, it is the other way around, and only in the aft cargo compartment where the 707 is actually the smaller dimension for fuselage height. The 727, 737 and 757 have a taller aft cargo compartment by 11.96 inches. The passenger cabins are pretty much all the same except for interior fittings. You can find all of the dimensions under Aircraft Description in the following link.

What is the other way around? I said the 707 fuselage (not the cabin) is taller from top to bottom. I wasn't referring to any specific part of the fuselage. Check the Boeing drawings and you will find that the 707 fuselage dimension vertically, at least forward of the wing, is taller than the 727/737. The width of the same.
 
speedygonzales
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RE: B737 Vs B757 Cockpit/Nose

Wed Sep 04, 2013 9:04 am

Quoting L0VE2FLY (Reply 2):
nothing defines a 737 like its signature nose.

Yeah, in a negative way   
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CALTECH
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RE: B737 Vs B757 Cockpit/Nose

Wed Sep 04, 2013 2:48 pm

Quoting Viscount724 (Reply 15):
What is the other way around? I said the 707 fuselage (not the cabin) is taller from top to bottom. I wasn't referring to any specific part of the fuselage. Check the Boeing drawings and you will find that the 707 fuselage dimension vertically, at least forward of the wing, is taller than the 727/737. The width of the same.

If you could show that, that would be great. I still come up with the same as before, variance of just a few fractions which could be atributed to the structure and fastening of interior coverings. As far as the Interior dimensions, I do not believe a foot would be alllowed to be wasted space, and haven't seen it. If we use thicker Gill Patch in the cargo compartments, there is a formula to adjust the weight and balance of the aircraft. And it changes the interior dimesion ever so slightly. Tenths of a inch. The 707 seems to be just about a straight tube fore and aft of the wing, all the other Boeing narrowbodies are deeper vertically aft of the wing, and that is in the aft cargo compartment vertical dimension. The passenger cabins stay the same. Unless I am reading it wrong, interior dimensions;


707
Fore of the wing- 130.6
Aft of the wing---- 130.6

727
Fore of the wing- 130.3
Aft of the wing---- 140.3

737
Fore of the wing- 130.5
Aft of the wing---- 133.1

757
Fore of the wing- 130.3
Aft of the wing---- 140.2

On the 757, in the wheel well, one can see the 1 foot drop from the front of the wheel well to the back. Very noticeable.

[Edited 2013-09-04 08:01:26]
UNITED Would Be Nice
 
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Buyantukhaa
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RE: B737 Vs B757 Cockpit/Nose

Wed Sep 04, 2013 4:02 pm

Quoting Mender (Reply 8):

It's surprising how many people don't realise the 757 fuselage has a difference in cross sectional height fore and aft of the wing box.

And I was one of them - and now that I know, I actually see it clearly on pics. One learns something new every day...

Quoting CALTECH (Reply 9):
Seems the 727 and 737 also share this difference which increases the height of the aft cargo compartments.

I can see it clearly on the 727 images, but not on the 737...

Quoting CALTECH (Reply 17):
737
Fore of the wing- 130.5
Aft of the wing---- 133.1

OK 2.6 inch is 6.5 cm, not that much. Is it the same throughout all 737 series?
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DL_Mech
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RE: B737 Vs B757 Cockpit/Nose

Thu Sep 05, 2013 12:33 am

Quoting CALTECH (Reply 17):
If you could show that, that would be great. I still come up with the same as before, variance of just a few fractions which could be atributed to the structure and fastening of interior coverings.

Here are some interesting cross section pics of the 707. I know you've been in the forward cargo pit of a 757, there's no way a row of seats could fit in there......


View Large View Medium
Click here for bigger photo!

Photo © AirNikon Collection-Pima Air and Space Museum
View Large View Medium
Click here for bigger photo!

Photo © Orlando Sotomayor

This plane is built to withstand anything... except a bad pilot.
 
Viscount724
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RE: B737 Vs B757 Cockpit/Nose

Thu Sep 05, 2013 1:30 am

Quoting CALTECH (Reply 17):
Quoting Viscount724 (Reply 15):
What is the other way around? I said the 707 fuselage (not the cabin) is taller from top to bottom. I wasn't referring to any specific part of the fuselage. Check the Boeing drawings and you will find that the 707 fuselage dimension vertically, at least forward of the wing, is taller than the 727/737. The width of the same.

If you could show that, that would be great. I still come up with the same as before, variance of just a few fractions which could be atributed to the structure and fastening of interior coverings.

In the following Boeing documents, scroll down past the tables at the beginning to the first page of aircraft drawings (section 2.2). You will find the vertical fuselage height is shown just forward of the wing.

707 - 14 ft. 2.5 in.
727 - 13 ft. 2 in. in forward fuselage, 14 ft. further back
737 - 13 ft. 2 in.
757 - 13 ft. 2 in.

707 fuselage slightly more than 1 ft. deeper top to bottom than the 737 and 757, and also the 727 in the forward part of the fuselage.

707:
http://www.boeing.com/assets/pdf/commercial/airports/acaps/707sec2.pdf

727:
http://www.boeing.com/assets/pdf/commercial/airports/acaps/727sec2.pdf

737:
http://www.boeing.com/assets/pdf/commercial/airports/acaps/737sec2.pdf

757:
http://www.boeing.com/assets/pdf/commercial/airports/acaps/753sec2.pdf
 
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CALTECH
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RE: B737 Vs B757 Cockpit/Nose

Thu Sep 05, 2013 5:07 am

Quoting Viscount724 (Reply 20):
You will find the vertical fuselage height is shown just forward of the wing.

Thanks, I stand corrected. It looked like that was the height of the top of the fuselage above the ground on the 707 drawing. The 707 seems to waste a foot of fuselage forward of the wing in the vertical dimension compared to the other narrowbodies, must be in the structure like intercostels. Looks like the aft fuselages, at least on the 727/757 are the same as the 707, the 737 seems to be a bit smaller there than the others too. The fuselage forward of the wing was made shorter on the 727/737/757. The differences are in the vertical dimension of the cargo pits. The passenger cabins are all the same in width and height. Thanks for your input Viscount724.

[Edited 2013-09-04 22:15:24]

[Edited 2013-09-04 22:17:31]
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HAWK21M
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RE: B737 Vs B757 Cockpit/Nose

Fri Sep 06, 2013 8:56 am

Quoting OldAeroGuy (Reply 13):
After the 757 was certified, I asked Jack Wimpress, the 757 Chief Technical Engineer what he thought the biggest error was on the development program.

His answer was not having the same lower lobe for the whole airplane. Early wind tunnel data indicated the deeper forward lower lobe had an unacceptable impact on directional stability for some conditions. Later testing showed there was no issue but it was too late to change the airplane production plan.

Educational........Thanks.
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