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Boeing 707 Oval Fuselage Vs DC-8 Double-Bubble  
User currently offlineBlackbird From , joined Dec 1969, posts, RR:
Posted (6 years 7 months 1 week 4 days ago) and read 10065 times:

From what I remember Douglas based it's double-bubble on older propeller designs it made. Boeing in it's design used an ovalized fuselage.

What techniques were used by Boeing to produce this ovalized shape and not a double-bubble. Why did Boeing choose not to use a double-bubble, and how was Boeing able to alter it's fuselage width several times without having to spend incredible amounts of money re-designing the plane (was it partially covered by the C-135/KC-135 program?)? Was it actually all that expensive to do?

Also... when did Douglas achieve it's 146 inch fuselage width with the DC-8? Was it in 1955?


Andrea kent

15 replies: All unread, jump to last
 
User currently offline411A From United States of America, joined Nov 2001, 1826 posts, RR: 8
Reply 1, posted (6 years 7 months 1 week 3 days 22 hours ago) and read 10038 times:

Ah, well, a slight bit of mis-information there, Blackbird.

Douglas civil propeller designs (specifically DC4/6/7) used an almost circular fuselage design, modified by being just slightly taller than it is, wide.
No 'double-bubble, there.

On the other hand, Boeing most definitely had a 'double bubble' design with their post war civil piston airplane...the Boeing Stratocruiser.

And, yes, I've flown the B377...the Stratocruiser was quite unique for its time.
Superchargers and turbochargers on each engine.
And, pretty much an all electric systems airplane, except for the brakes and nose wheel steering.
Speaking of the brakes on the Stratocruiser, they were of the Hayes expander tube variety.
You could hear a Stratocruiser taxiing from a half a mile away, from the squeal from these Hayes brakes.

And, if you look very closely at the B707 fuselage cross section, you might be surprised at what you find.


User currently online113312 From United States of America, joined Apr 2005, 564 posts, RR: 1
Reply 2, posted (6 years 7 months 1 week 3 days 22 hours ago) and read 10026 times:

The Boeing 707 is a "double bubble" cross section with the upper lobe larger than the lower. It is easily seen if you look at sections on this website where the planes are being broken up.

The original 717, which was actually the KC-135, has the original cross section of the 367-80 prototype where the diameter of the upper lobe is smaller. The original design was for 5 across coach seating. Although not yet in production, Douglas was offering the airlines 6 across seating and Boeing was pressured to match this configuration by it's potential airline customers.


User currently offlineSEPilot From United States of America, joined Dec 2006, 6683 posts, RR: 46
Reply 3, posted (6 years 7 months 1 week 3 days 21 hours ago) and read 10025 times:

Quoting Blackbird (Thread starter):
What techniques were used by Boeing to produce this ovalized shape and not a double-bubble. Why did Boeing choose not to use a double-bubble, and how was Boeing able to alter it's fuselage width several times without having to spend incredible amounts of money re-designing the plane (was it partially covered by the C-135/KC-135 program?)? Was it actually all that expensive to do?

The first decision (from the 367-80 cross section to the KC-135) was not expensive, as the -80 had been built specifically as a demonstrator, not even a prototype, and so no dedicated tooling had been built for it. But Boeing did expect to build the 707 and the KC-135 from the same tooling. Bear in mind that when Boeing received the first order for the KC-135, it was for 25 and ONLY 25; the only reason they got that (Lockheed had won the competition for the jet tanker, not Boeing) was that Curtis LeMay jumped up and down  hissyfit  and said he wanted jet tankers NOW and didn't care who made them, so the Air Force ordered 25 from Boeing, telling them in no uncertain terms that those would be the only ones they'd ever build. (It wasn't until the 707 program was well established that it became evident that the Lockheed tanker was not coming that they ordered the KC-135 in quantity.) The 707 at this time had 5 abreast seating, but the DC-8 (which existed only on paper) offered 6, and as airlines started placing orders the DC-8 was winning, even though the 707 offered earlier delivery. Bill Allen had vivid memories of having Boeing planes bested by later entries in the civil market every time going back to the 247, and wasn't going to risk it again, and so made the decision to widen the fuselage again, which was a very expensive decision, as the KC-135 at that point had entered production and couldn't be changed, and was going to be only 25 planes. Boeing had however planned on building 707's on the same tooling, and so they had tooled for full production (unlike Douglas and the DC-9.) Allen was therefore committing to two sets of tooling, one (at that time, anyway) guaranteed to lose bucketloads of money, and the other very uncertain as to whether or not it would pay off. Remember that Boeing had lost lots of money on every commercial airliner it had ever built, so this was an extremely risky move for Boeing to make. But this was the decision that made the 707 a success, and when both planes were flying and the performance of the 707 proved to be better than the DC-8 that sealed its success. In my opinion it was one of the gutsiest moves ever made by an industrial company, ever. The fact that the Air Force went on to order hundreds of KC-135's was a bonus; this did not happen until well after this decision was made.



The problem with making things foolproof is that fools are so doggone ingenious...Dan Keebler
User currently offlineRC135U From United States of America, joined May 2005, 293 posts, RR: 0
Reply 4, posted (6 years 7 months 1 week 3 days 20 hours ago) and read 9988 times:

Quoting SEPilot (Reply 3):
(Lockheed had won the competition for the jet tanker, not Boeing)



I've heard about this winning tanker design from Lockheed numerous times but have never seen any drawings or performance data. Are there any extant?


User currently offlineSEPilot From United States of America, joined Dec 2006, 6683 posts, RR: 46
Reply 5, posted (6 years 7 months 1 week 3 days 18 hours ago) and read 9963 times:

Quoting 113312 (Reply 2):
The original 717, which was actually the KC-135, has the original cross section of the 367-80 prototype where the diameter of the upper lobe is smaller.

This is not correct; the Air Force wanted a larger cross section than the 367-80, and so Boeing increased the width (I believe) by 12". If you look closely at pictures of the 367-80 you can see that the sides appear pretty much vertical (i.e. more of a flattened oval cross-section) and the KC-135 appears round. That would have given the 5 abreast seating of the first 707 proposals. When they realized they were losing sales to the DC-8 they increased it another 12", making it 1" wider than the DC-8.

Quoting RC135U (Reply 4):
I've heard about this winning tanker design from Lockheed numerous times but have never seen any drawings or performance data. Are there any extant?

I've asked the same question on numerous occasions, and have searched the web with no results. I posted a thread on the topic but got no replies. I don't even have any idea why Lockheed never delivered it.



The problem with making things foolproof is that fools are so doggone ingenious...Dan Keebler
User currently offlineAvioniker From United States of America, joined Dec 2001, 1109 posts, RR: 11
Reply 6, posted (6 years 7 months 4 days 13 hours ago) and read 9606 times:

Quoting SEPilot (Reply 3):
But this was the decision that made the 707 a success, and when both planes were flying and the performance of the 707 proved to be better than the DC-8 that sealed its success. In my opinion it was one of the gutsiest moves ever made by an industrial company, ever. The fact that the Air Force went on to order hundreds of KC-135's was a bonus; this did not happen until well after this decision was made.

I have a question here; you are aware that the 717, 720, 707, KC-135, KC-137, and 717 are six different planes entirely?
The 25 KC-135's initial order, of which 8 were built before the order were finalized, were the first 717's and the subsequent fleet was based on the "newer" 720. The Lockheed design, alas, suffered the same fate as the MD-12 even though the company didn't go away like McD did. Many of the engineers from Lockheed went to Seattle so a lot of the ideas are in the 135 fleet.
 Smile



One may educate the ignorance from the unknowing but stupid is forever. Boswell; ca: 1533
User currently onlineJetlagged From United Kingdom, joined Jan 2005, 2535 posts, RR: 24
Reply 7, posted (6 years 7 months 4 days 12 hours ago) and read 9594 times:

Quoting Avioniker (Reply 6):
you are aware that the 717, 720, 707, KC-135, KC-137, and 717 are six different planes entirely?

Six entirely different planes? Surely the C-137 is a military 707, basically the same airframe. As the first KC-135s had no civil production equivalent the civil model number 717 was not used externally. I don't see how it counts as a separate aircraft from the KC-135. The "other" 717 was a marketing identity for what eventually became the 720, again same aircraft, different designation.



The glass isn't half empty, or half full, it's twice as big as it needs to be.
User currently offlineViscount724 From Switzerland, joined Oct 2006, 24109 posts, RR: 23
Reply 8, posted (6 years 7 months 3 days 15 hours ago) and read 9519 times:

Quoting Avioniker (Reply 6):
I have a question here; you are aware that the 717, 720, 707, KC-135, KC-137, and 717 are six different planes entirely?

As far as I know, C-137 was the USAF's desigination for the 707. The two 707-320Bs used as Air Force One were designated VC-137C. To Boeing, they were 707-353Bs.

The 720 does have many differences from the rest of the 707 family but it was originally referred to as 707-020 and the designation was only changed to 720 at the request of UA's president who thought a higher number than 707 would have certain marketing advantages. AA always referred to their 720s as 707s and identified them as 707 on the exterior of the aircraft.

Quoting Avioniker (Reply 6):
The 25 KC-135's initial order, of which 8 were built before the order were finalized, were the first 717's and the subsequent fleet was based on the "newer" 720.

How were later KC-135s based on the 720? They didn't have the wider 707/720 fuselage.


User currently offlineSEPilot From United States of America, joined Dec 2006, 6683 posts, RR: 46
Reply 9, posted (6 years 7 months 2 days 23 hours ago) and read 9464 times:

Quoting Avioniker (Reply 6):
I have a question here; you are aware that the 717, 720, 707, KC-135, KC-137, and 717 are six different planes entirely?

Yes, I was. I believe that the 707-100 and 707-300 series also have different wings, engines, and landing gear, so they are as different as the 707's and 720's are.

Quoting Avioniker (Reply 6):
The Lockheed design, alas, suffered the same fate as the MD-12 even though the company didn't go away like McD did. Many of the engineers from Lockheed went to Seattle so a lot of the ideas are in the 135 fleet.

This is the first concrete information I have heard about the Lockheed tanker. Do you have any other information, especially why Lockheed ditched it, since they had the order in hand?



The problem with making things foolproof is that fools are so doggone ingenious...Dan Keebler
User currently onlineJetlagged From United Kingdom, joined Jan 2005, 2535 posts, RR: 24
Reply 10, posted (6 years 7 months 2 days 18 hours ago) and read 9428 times:

Quoting Viscount724 (Reply 8):
How were later KC-135s based on the 720? They didn't have the wider 707/720 fuselage.

The confusion here is probably because both the KC-135 and the 720 were known, for a short time, as the 717, same model number - different aircraft!



The glass isn't half empty, or half full, it's twice as big as it needs to be.
User currently offlineSEPilot From United States of America, joined Dec 2006, 6683 posts, RR: 46
Reply 11, posted (6 years 7 months 2 days 16 hours ago) and read 9412 times:

Quoting Jetlagged (Reply 10):
The confusion here is probably because both the KC-135 and the 720 were known, for a short time, as the 717, same model number - different aircraft!

I did not realize that the 720 also had the 717 designation; that makes 3 totally different aircraft that at one time or other were known as the 717. Will Boeing recycle it again for the 737RS????



The problem with making things foolproof is that fools are so doggone ingenious...Dan Keebler
User currently offlineAvioniker From United States of America, joined Dec 2001, 1109 posts, RR: 11
Reply 12, posted (6 years 7 months 19 hours ago) and read 9298 times:

Very simply put; money.
The F-104 was killing them and as far as spendable cash (Lockheed was buying houses, barns, and farmland all over the world for every country that bought the plane); Boeing had money and Lockheed was overextended trying to build a competitive missle (Martin ended up with that contract), an economical transport (the military, aside from the Navy, wasn't really interested in the turboprop L-188 and the L-100/C-130 had legs too short) and stay solvent. . . .
Some of the more far sighted people in the company went to Mojave and Palmdale and managed to stay afloat with the darker side of the company but the biggest moneymakers for them were the C-5 and the AF wanted the 141 in quantity. Niether plane would have made a viable tanker for way too many aerodynamic reasons to go into here.
I'll see if I can find any of my 141 pictures with the wingtip and tail drogue simulators (but I won't be home for a few weeks). That was interesting.

Here's some information from the source.

http://www.boeing.com/history/boeing/707.html

http://www.boeing.com/history/boeing/kc135.html

For the rest of the fleet
http://www.boeing.com/history/master_index.html


 Smile



One may educate the ignorance from the unknowing but stupid is forever. Boswell; ca: 1533
User currently offlineSEPilot From United States of America, joined Dec 2006, 6683 posts, RR: 46
Reply 13, posted (6 years 7 months 18 hours ago) and read 9292 times:

Quoting Avioniker (Reply 12):
but the biggest moneymakers for them were the C-5

The tanker contract was long before the C-5 was even a gleam in anyone's eye; the contract was also written before the C-141 was even on the drawing board. This was in 1955, I believe. That's even before the f-104 was causing the problems you state, although it could have been an issue during the design of the tanker.



The problem with making things foolproof is that fools are so doggone ingenious...Dan Keebler
User currently offlineAvioniker From United States of America, joined Dec 2001, 1109 posts, RR: 11
Reply 14, posted (6 years 6 months 4 weeks 1 day 18 hours ago) and read 9236 times:

Okay
Let me make my point more clearly.
Lockheed wasn't making any money to do anything new, after WW II, until they started making money off the High Wing Transport Program. The AF wasn't in any position to offer additional funds or subsidies as they were buying lots of bombers, tankers, fighters, and a limited number of C-133's (They were funding their development and deployment to Dover and a couple of other bases while waiting for someone to build a low fuselage/high wing jet transport that could operate with virtually no ground support equipment. The 133 was close but not a jet and needed some very specialized equipment.)
My Father was involved with the logistical end of the transport procurement program in 1956 and used to bring home a number of very interesting pictures in the 50's (and that's how I happen to have some drawings of a Lockheed tanker and a couple of high wing transports). The 141 was indeed on the drawing boards in the 50's. The technology and money simply didn't exist to produce it yet. I firmly believe that Lockheed's "entry" in the tanker program was one of many attempts to get money to continue its existance. The Palmdale facility didn't provide enough to support the other enterprises so they had to look elsewhere.
As to the F104 and lawsuits. I believe the first was in 1956 or 57 when one skidded through a cemetary on a ferry flight from the factory to EDW. They were killing people with them fairly regularly by 1959. I watched one go into the Wheelus riding stables in 60 or 61. The plane cost the makers a lot before the government stepped in to help absorb some of the costs.
 Smile



One may educate the ignorance from the unknowing but stupid is forever. Boswell; ca: 1533
User currently offlineSEPilot From United States of America, joined Dec 2006, 6683 posts, RR: 46
Reply 15, posted (6 years 6 months 4 weeks 1 day 16 hours ago) and read 9223 times:

Quoting Avioniker (Reply 14):

Let me make my point more clearly.

Thank you very much for the information; that clarifies a lot. I have always wondered what happened to the Lockheed tanker, and you have given me the first concrete information. Could you post the drawings you say you have of the Lockheed tanker and the transports? I would love to see them.



The problem with making things foolproof is that fools are so doggone ingenious...Dan Keebler
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