MTY2GVA From Switzerland, joined Nov 2005, 82 posts, RR: 0 Posted (10 years 2 months 4 weeks 1 day 16 hours ago) and read 25035 times:
I know this may sound a little weird, but seeing the floorplans of different 747's some with around 24 business seats in them I am wondering if it wouldn't be more economical to do a 10 meter longer plane than the added weight/aerodynamic effect of a second floor.
Tengo orgullo de ser del norte del mero San Luisito...
Concentriq From United States of America, joined Jan 2005, 368 posts, RR: 0
Reply 3, posted (10 years 2 months 4 weeks 1 day 15 hours ago) and read 24851 times:
I think im right on this: The passenger 747 came as an afterthought to a freight version, where the "hump" is where living quarters would be (pilots, rest cabins, supplies, etc) leaving two decks below to cargo. this allowed for front load capabilities.
the idea of lounge/first class "upstairs" was really welcome in the days of luxury travel, and 747 being a great design like it is, it stuck around. also:
RedDragon From United Kingdom, joined Jul 2004, 1135 posts, RR: 6
Reply 9, posted (10 years 2 months 4 weeks 1 day 14 hours ago) and read 24562 times:
The hump actually increases the efficiency of the airframe due to area ruling effects (basically, bulging out the front and rear of the fuselage relative to the centre to compensate for the larger wing area in the centre). In fact, the extended -300/-400 hump supposedly offers an improvement over the shorter, original design. Removing the hump wouldn't be as obvious an aerodynamic step as it might seem
Of course, the main reason that Boeing doesn't change the design so drastically right now is that it'd be a hideously complex and expensive redesign - they might as well just redesign everything else as well. Hypothetically, however, this kind of question raises some interesting thoughts and tradeoffs.
AKelley728 From United States of America, joined Dec 1999, 2197 posts, RR: 5
Reply 11, posted (10 years 2 months 4 weeks 1 day 14 hours ago) and read 24481 times:
Quoting MTY2GVA (Thread starter): I know this may sound a little weird, but seeing the floorplans of different 747's some with around 24 business seats in them I am wondering if it wouldn't be more economical to do a 10 meter longer plane than the added weight/aerodynamic effect of a second floor.
The cockpit is also on the upper level. Having the cockpit on the upper level allows the nose of the 747 to flip up for cargo operations (when it's built specifically as a freighter).
AADC10 From United States of America, joined Nov 2004, 2148 posts, RR: 0
Reply 13, posted (10 years 2 months 4 weeks 1 day 13 hours ago) and read 24432 times:
Do the grey bands in the drawing indicate where the plane is lengthened? If so, it looks like it would add a row or two to the upper deck.
I have always thought that the reason for the upper deck was to allow a completely open lower deck for freighters. If there is a significant aeordynamic advantage to the hump, why didn't other planes copy it?
Aloha73g From United States of America, joined Jul 2003, 2401 posts, RR: 4
Reply 14, posted (10 years 2 months 4 weeks 1 day 13 hours ago) and read 24394 times:
Quoting AADC10 (Reply 13): I have always thought that the reason for the upper deck was to allow a completely open lower deck for freighters.
Yep, as previously mentioned the 747 was designed originally with a primarily freight role in mind...just in case the passenger version was a dud. Boeing figured that if the market for a jumbo passenger jet fell through, they could market a mega freight carrier. Fortunately they did well in both regards.
Aloha Airlines - The Spirit Moves Us. Gone but NEVER Forgotten. Aloha, A Hui Hou!
MTY2GVA From Switzerland, joined Nov 2005, 82 posts, RR: 0
Reply 16, posted (10 years 2 months 4 weeks 1 day 13 hours ago) and read 24355 times:
I have to agree that the hump is awesome and its a beautiful plane. In the cargo version the hump is very helpful too. I've flown in first class in the front of the first deck and its great to know you're literally in front of the aircraft.
Tengo orgullo de ser del norte del mero San Luisito...
Dvk From United States of America, joined Jun 2000, 1058 posts, RR: 1
Reply 17, posted (10 years 2 months 4 weeks 1 day 13 hours ago) and read 24353 times:
Quoting Aloha73g (Reply 14): Yep, as previously mentioned the 747 was designed originally with a primarily freight role in mind...just in case the passenger version was a dud.
When the 747 was originally designed, there was widespread belief that commercial flights would become mostly supersonic in the not too distant future. The 747 was therefore designed for optimal use as a freighter, to assure it would have greater success in the long term.
I'm not dumb. I just have a command of thoroughly useless information.
ANother From , joined Dec 1969, posts, RR:
Reply 19, posted (10 years 2 months 4 weeks 1 day 13 hours ago) and read 24312 times:
Quoting Aloha73g (Reply 14): Yep, as previously mentioned the 747 was designed originally with a primarily freight role in mind...
It may be just a 'senior's moment' but wasn't the original B747 design Boeing entry into the USAF campaign for a heavy-lift military freighter - the one that the C5 won?
Designed as a freighter, Boeing cut their losses and adapted the design to a Passenger version. I can't remember when the first B747F was delivered but it was quite a few years later - but the original design came in handy as it allowed the the nose-door.
Sonic67 From United States of America, joined Jan 2005, 293 posts, RR: 0
Reply 21, posted (10 years 2 months 4 weeks 1 day 13 hours ago) and read 24246 times:
Yes Boeing lost the competition because the defense department felt that Boeing already had too many large projects such as B-52, KC-135 etc. I think at first they where sorry that they had chosen Locked with all the early problems and cost over runs.
B2707SST From United States of America, joined Apr 2003, 1384 posts, RR: 58
Reply 22, posted (10 years 2 months 4 weeks 1 day 13 hours ago) and read 24220 times:
Quoting Supa7E7 (Reply 20): Will the 747-800 pax have a longer upper deck than the 747-400? Or is the stretch on level 1 only? The above pic did not clarify this.
Yes - the upper aircraft is 747-8I, which will have both decks stretched forward of the wing. The lower aircraft, the 747-8F, has no use for a longer upper deck, so only the main deck will be stretched. The -8F has a longer stretch than the pax to compensate for the absent upper deck and preserve center-of-gravity balance.
RedChili From Norway, joined Jul 2005, 2386 posts, RR: 4
Reply 23, posted (10 years 2 months 4 weeks 1 day 13 hours ago) and read 24200 times:
Quoting MTY2GVA (Thread starter): I am wondering if it wouldn't be more economical to do a 10 meter longer plane than the added weight/aerodynamic effect of a second floor.
Firstly, this would create airport problems. How about a tailstrike at take-off? And how about the space at the gates? Adding 10 meters would mean that it would be longer than 80 meters. It wouldn't fit into today's terminals.
Secondly, the cockpit would have to go on the first floor, thereby losing several seat rows there. It's doubtful whether this plane would seat more than the current 744.
Quoting AADC10 (Reply 13): If there is a significant aeordynamic advantage to the hump, why didn't other planes copy it?
Other manufacturers cannot copy it, because Boeing has a patent/copyright on that shape. And for Boeing, adding a second floor on a 737 would look really strange, and since the second floor would have to be narrower than the first floor, the cockpit would probably have to be the fighter airplane style!
RedDragon From United Kingdom, joined Jul 2004, 1135 posts, RR: 6
Reply 24, posted (10 years 2 months 4 weeks 1 day 13 hours ago) and read 24189 times:
Quoting Sonic67 (Reply 18): I have heard a rumor that the upper deck may get sky light windows can anyone confirm or dispel this?
They're not going to run along the length of the upper deck, but seem to be a group more or less above the main staircase. Boeing is trying to open out the "public" (non-seating) areas to achieve more of the "grand staircase" feel Airbus will have with the A380.
: It's ironic that the 748 is also being same in the same light -- mainly a freighter. Lets hope it also sees plenty of passengers.
: Anyone lucky enough to have flown "upper deck" on a long haul flight would be very sad to see the hump removed. It's a great place, rather private and
: The 747 started life as a competitor against the military Lockheed C-5 Galaxy - therefore the front cargo door option and the 2nd floor flight deck. W
: The "serrated" design produces a better mix of the engine's exhaust gas and air that passes through and around the nacelle. A better mix reduces the
: Actually, Boeing's entry in the HLX competition was high-winged. The reason the 747 was built with the upper deck was for civilian freighter use. The
: Not only is the the upper deck being used for passenges but above that in the crown of the hump there might be small rest bunks for some passengers du
: IIRC - the "Sky-Loft" is located closer to the area above door 4. KLM 744 already have a crew rest there and Boeing has studied how to use that space
: I think it's actually the crown of the main fuselage where Boeing is contemplating adding these areas. I don't think there's enough space in the crow
: Absolutely corect, Prebennorholm. Here's a quote from an article from ATWO that goes into the rationale for the design: Here's the link to the entire
: Engine noise is higher when the exiting air have high speed compared to the surrounding air. Sound is made due to shear-forces between air-molecules.
: I've sat there many times, you can't see down the runway, even if you lean into the porthole of the window and squash your face against the glass.
: LOL, your fellow passengers must have had some mixed feelings about you while doing this!
: This patent should have expired around 10-15 years ago.
: While the noise theory is correct, I hate to break it to everyone, cheverons do come with a thrust/fuel economy penalty. Ok, its small, about 0.125%.
: I think the Black Eye Peas speak for Boeing in this case. "MY hump"
: Aagh, I should have noted the 744 is QC2 on arrival. The above numbers are take off. For comparison, the 777 and 340 are both QC0.5 (yes, half!) for
: Funny that many of those same people who like the upper deck whine about narrow body airplanes on long haul flights.
: Thank you. I suspected it to be some penalty, but I've never seen numbers on it before.
: Nope. Area rule only really applies to supersonic air flow, which is why you see advanced (supersonic) fighters have "hourglass figures". This is so
: Supersonic and transonic flight, +Mach 0.8. Even in transonic flight, there is local areas of supersonic flow. The area rule is one factor why Citati
: Would love to see that... Wouldn't you after having all that space.... Rob
: The upperdeck ceiling panels are basically flush to the aircraft frames. Tod
: Cargo 747 pilots have to careful they dont have any hot drinks in their cockpit when activating the open nose switch,as they have to sit at back 90 de
: It is a wonderful place The aisle is often very wide, and there is plenty of space - much more spacious then a narrow body.
: just think......if the 747 had won, would we all be flying around on C-5's now?
: hmmmm. obviously never seen a carvair DC4 conversion! http://airlines.afriqonline.com/images/plne3136.jpg
: Um... the Citation X doesn't use the area rule. That's why the fuselage keeps getting wider and wider until you meet the middle of the wing, where it
: I noticed this too. The 3-3 (2-2-) 757s are hell for US-UK flights, but the 3-3 (2-2) upper deck of a 747 is awesome...
: Bohlman, I'm not under the impression that the 747 was designed with the hump for aerodynamic effects - however, I am under the impression that they c
: I still marvel at the looks of this beautiful plane. The latest renderings only bolster the love affair. Ahhh...
: The Carvair was made before Boeing got the copyright for the 747 hump.
: Nasa pages states othervise: As you can see, the citation x uses the area rule both locally and generally. Do a search next time.[Edited 2005-11-19 0
: During the heyday of the Sonic Cruiser program, Boeing tried to drum up airline interest in 747 speed fairings to increase cruise speed from better ar