Why did American Airlines go with 707 over DC-8?

JCTJennings · Fri Nov 09, 2018 5:46 pm

longhauler wrote:
JCTJennings wrote:
All passenger 707s had three turbo compressors, the only ones with two were dedicated all cargo 707-320Cs with no windows and thus not convertible.

Check out American's passenger -123Bs, -323Bs and -323Cs. They all have only two turbo compressors. I suspect they were the only airline that specified this during construction. It used to confuse the hell out of me as a young lad, atop the roof of T1 in YYZ, trying to identify aircraft.

Thank you for the rest of your information. Off hand, just for information, how much lighter was the empty weight of the 720B than say the 707-120B?

720s were typically 10,000lbs lighter than 707-120s in terms of empty weight and from 25,000 to 30,000lbs lighter on MTOW. I note your comments on turbo compressors, but I have never seen a passenger 707 with less than three and why would American think that they needed less air conditioning and pressurisation capacity than anyone else? Bear in mind that American never referred to its 720s as such and always referred to them as 707s, which was what they painted on the aircraft.

citationjet · Fri Nov 09, 2018 6:19 pm

JCTJennings wrote:
I note your comments on turbo compressors, but I have never seen a passenger 707 with less than three and why would American think that they needed less air conditioning and pressurisation capacity than anyone else?

707-123B with 2:

707-323C with 2:

707-323B with 2:

timz · Fri Nov 09, 2018 6:25 pm

JCTJennings wrote:
I have never seen a passenger 707 with less than three

https://www.flickr.com/photos/xsacman/6 ... 441866582/

Think if it had three, one would be on #4.

Also this one -- think it's actually a 720B with an HF antenna?

https://www.flickr.com/photos/xsacman/6 ... 441866582/

BoeingGuy · Fri Nov 09, 2018 6:33 pm

timz wrote:
JCTJennings wrote:
I have never seen a passenger 707 with less than three

https://www.flickr.com/photos/xsacman/6 ... 441866582/

Think if it had three, one would be on #4.

Also this one -- think it's actually a 720B with an HF antenna?

https://www.flickr.com/photos/xsacman/6 ... 441866582/

Most 720s had HF antennas. UA and EA were notable exceptions.

This is a cool thread.

mga707 · Fri Nov 09, 2018 6:58 pm

timz wrote:
JCTJennings wrote:
I have never seen a passenger 707 with less than three

https://www.flickr.com/photos/xsacman/6 ... 441866582/

Think if it had three, one would be on #4.

Also this one -- think it's actually a 720B with an HF antenna?

https://www.flickr.com/photos/xsacman/6 ... 441866582/

The caption on the 2nd photo is correct: 707-123B. American's 720Bs did not have HF antennas.

WA707atMSP · Fri Nov 09, 2018 8:04 pm

mga707 wrote:
timz wrote:
JCTJennings wrote:
I have never seen a passenger 707 with less than three

https://www.flickr.com/photos/xsacman/6 ... 441866582/

Think if it had three, one would be on #4.

Also this one -- think it's actually a 720B with an HF antenna?

https://www.flickr.com/photos/xsacman/6 ... 441866582/

The caption on the 2nd photo is correct: 707-123B. American's 720Bs did not have HF antennas.

I've read that when AA sold some of their HF-less 720Bs, they interchanged the vertical fins with fins from 707-123Bs that AA was keeping, because the airlines buying AA's 720Bs wanted them with HF antennas. This is why there are pictures in the database from the mid to late 1970s of AA 707s with no HF antenna.

longhauler · Wed Dec 19, 2018 3:26 am

global2 wrote:
So I believe I read that when Boeing expanded the width of the fuselage to accommodate six abreast seating, it ended up being six inches wider than the DC-8. I wonder how wide the seats on the DC-8 were then? I know they were quite unique in design: attached directly to the wall, middle seat slightly wider than the aisle & window, etc. I only mention this because of all the histrionics I see posted on Anet about the supposedly excruciatingly narrow seats on the 737 (same width as the 707) vs. those huge, luxurious seats on the Airbus--a whopping half inch wider. I've never read anything where people complained about seat width on the DC-8.

The fuselage width of the 707 was slighly less than an inch wider than the DC-8. The cabin interior width was about half an inch wider in the 707 than DC-8. Depending on aisle or armrest width, I would be surprised if the actual seat cushion width was any different between the two. Certainly not where passengers would notice.

Newark727 · Wed Dec 19, 2018 5:17 am

Interesting how much variation there was in the 707 family, compared to the very standardized product lineups you see today. I guess a lot of it is Boeing learning as they went, and maybe airlines losing their appetite for buying something overly specialized.

BlueberryWheats · Wed Dec 19, 2018 6:27 am

Newark727 wrote:
Interesting how much variation there was in the 707 family, compared to the very standardized product lineups you see today. I guess a lot of it is Boeing learning as they went, and maybe airlines losing their appetite for buying something overly specialized.

Probably more conscious of eventually trying the sell the aircraft on in later years too. Going to be easier to sell a standardised product than one overall specialised to the original airline's needs I suppose.

SEPilot · Wed Dec 19, 2018 7:41 am

BlueberryWheats wrote:
Newark727 wrote:
Interesting how much variation there was in the 707 family, compared to the very standardized product lineups you see today. I guess a lot of it is Boeing learning as they went, and maybe airlines losing their appetite for buying something overly specialized.

Probably more conscious of eventually trying the sell the aircraft on in later years too. Going to be easier to sell a standardised product than one overall specialised to the original airline's needs I suppose.

Interesting that with today’s CAD systems making customized designs is far easier, at least from an engineering perspective, than it was when everything was done on paper, but both Boeing and Airbus do it far less now than Boeing and Douglas/MD did in the 50s and 60s. Perhaps certification requirements are a lot stricter than they were, or just that the industry is more matured so A & B are much more reluctant to customize things? I know when I was in the machine tool business and American machine tool makers were being squeezed out by the Japanese my company survived for a lot longer than most because we were willing to customize our machines much more than anyone else. But with only two manufacturers to choose from if neither will do it then the airlines have no choice. Back then there were more choices. But there is another possibility, since it seems that Boeing did it the most. Remember that this was the era that Boeing was trying very hard to overtake Douglas as the dominant airframe manufacturer, and it was by no means certain that they would succeed. Just as my company hung on to its market by being willing to customize, this may have been a deliberate strategy by Boeing to attract more customers. After they achieved dominance it was no longer necessary for them to do so.

TurboJet707 · Wed Dec 19, 2018 11:59 am

mga707 wrote:
timz wrote:
JCTJennings wrote:
I have never seen a passenger 707 with less than three

(...)
Also this one -- think it's actually a 720B with an HF antenna?

https://www.flickr.com/photos/xsacman/6 ... 441866582/

The caption on the 2nd photo is correct: 707-123B. American's 720Bs did not have HF antennas.

This is indeed a 707-123B, registration is N7505A. This is one of AA's first 707s and it was originally a 707-123 (so non-'B') with P&W JT3C turbojets. In the early sixties, AA sent those early straight-pipe 707s back to Boeing for conversion to 707-123B configuration, which involved changing the engines to JT3D turbofans, along with some aerodynamic improvements like the fitting of the 720s 'wing glove'. This conversion brought a large improvement in fuel burn and a notable decrease in noise and smoke. With the more powerful engines, the water injection system was no longer necessary so that was dropped at the same time.

I noted that these early AA 707s had four (!) turbo compressors before their conversion to -123Bs. I couldn't find a picture of N7505A pre-conversion, but her sister ships N7501A and N7503A clearly had four turbo's:

Note the smaller turbojet engines with their noise suppressor 'organ pipes' at the back. All four engine nacelles have the 'knuckles' for the turbo compressors on top.
After conversion, only two of those four compressors remained:

(this is N7505A after conversion. only two 'knuckles')

Archer · Wed Dec 19, 2018 12:35 pm

Good Morning. Great discussion.
Not able to read all but at 76 I remember some things from 1958 and '59. Back then American's slogan was "America's Leading Airline". If you are the leader then you go first, obviously. Therefore, no decision as to what to do. 707 ready, buy 707. DC-8 late, don't buy.
American at first advertised "First with Jets in the USA". Then National leased Pan American 707's for NY to Florida flights so American, being quick on their feet, changed the ads to "First with Jets Across the USA" Many ads showed the beautiful new 707's. An exciting time and of course the Electra's entered service at the same time.

Archer · Wed Dec 19, 2018 12:35 pm

Good Morning. Great discussion.
Not able to read all but at 76 I remember some things from 1958 and '59. Back then American's slogan was "America's Leading Airline". If you are the leader then you go first, obviously. Therefore, no decision as to what to do. 707 ready, buy 707. DC-8 late, don't buy.
American at first advertised "First with Jets in the USA". Then National leased Pan American 707's for NY to Florida flights so American, being quick on their feet, changed the ads to "First with Jets Across the USA" Many ads showed the beautiful new 707's. An exciting time and of course the Electra's entered service at the same time.

Archer · Wed Dec 19, 2018 12:37 pm

Guess I hit the submit button twice.

Revelation · Wed Dec 19, 2018 2:07 pm

TurboJet707 wrote:
While this did cause some delay in DC8 deliveries, the early 707 needed modifications too, around that same time. The 707 got a taller tail fin and a ventral fin to improve stability. Interestingly, the book also claims that one of the reasons that KLM opted for the DC8 instead of the 707 is that KL didn't trust the 707's 35-degree wing sweep, they feared that would be too much and thought the DC8's 30 degrees sweep would be safer. Of course, KLM's long relationship with Douglas will have played an important role as well.

BTW, it's funny to read the expectation in that same book that we would all be flying at Mach 3 in nuclear powered aircraft around 1970. How different did it turn out. If the author (who passed away a long time ago) would get a chance to have one look at large airport like AMS in 2018, I guess he would be rather underwhelmed: 60 years later, civil aircraft are still subsonic and look basically the same as the DC8 and 707 that he raved about...

Re: 707 and stability: Previous a.net discussions pointed me to a great interview series:

The D. P. Davies Interview on testing the Comets, Boeing 707, Britannia & Brabazon.

“The test pilots’ test pilot”, former CAA Chief Test Pilot D. P. Davies talks frankly about the civil aircraft that he put through his paces before being certified as safe in the UK.

The interview was conducted by Rodney Giesler in 1992 and edited by Mike Stanberry FRAeS.

https://www.aerosociety.com/news/audio- ... the-1940s/

If the links don't work, google 'soundcloud dp davies' to get direct links.

It's safe to say he was none too impressed with the original 707 he was asked to certify.

Re: how it turned out: It's kind of like saying a caveman would be surprised to see no dinosaurs but billions of humans instead. The fittest won out.

CWizard · Wed Dec 19, 2018 4:02 pm

The story I read, years ago, was William Allen approached Juan Trippe about the 707 and Mr. Trippe told Mr. Allen if they would make it wide enough to seat six across he would buy it. Mr. Allen agreed and Mr. Trippe placed the first order, and, of course, was the launch customer.
As someone else has mention, I really thought by now supersonic travel would be the norm. Current jetliners are slower than the original 707, which cruised at an equivalent ground speed of 608 mph. The 747 and 380 cruise at approximately 585.

LH707330 · Wed Dec 19, 2018 5:52 pm

SEPilot wrote:
DrPaul wrote:
A question I have following on from this discussion is this: what were the salient points that encouraged airlines to buy 707s rather than DC-8s, or DC-8s rather than 707s, when they were both fully in production?

I've only recently discovered that two stretched versions of the 707 were envisaged, with 45 and 55 foot fuselage extensions, making them 197 and 207 feet long, and a 10 foot wider wing span. Now they would have been quite a sight, the ultimate 'flying pencil'.

It's odd when I think back to when I used to see 720s coming into Heathrow, I used to think that they were quite large aeroplanes; nowadays, I think that 737-800s, which are only seven feet shorter than the 720, and the 737-900s, which are two feet longer, are quite small. I suppose this perception is because the average size of airliners has increased somewhat over the last 50 or more years.

As I said earlier, the high altitude-high speed performance of the 707 was definitely superior to the DC-8. I believe the range and payload of the 300 series was better as well. A lot of airlines were partial to Douglas, however, and the DC-8 being 6 abreast while the initial offering of the 707 was 5 abreast won some initial orders for Douglas. The other factor was that Boeing was much more successful in ramping up production, and was able to deliver with much better predictability. Donald Douglas was a great engineer, but not a great businessman, and when he completely underestimated the demand for the DC-9, he basically bankrupted the company trying to meet it and was forced to seek a merger partner. And he ended up with the worst one possible.

Stretching the 707 was much more difficult than the DC-8 because of the aft fuselage design. The 707 tapered along the fuselage axis, while the DC-8 held the top of the fuselage straight and tapered up to that line. This gave the DC-8 much more rotation clearance without having to lengthen the landing gear. But the real reason the 707 was never stretched was that Boeing was already thinking about the 747 by the time the issue of stretching the 707 came up.

As to the size of airliners, consider that there are regional jets now that are larger than the largest prop powered airliners.

What do you mean by "tapered around the fuselage axis?" The only downward taper to the 707 is the 2-3 inch taper at the fin leading edge, which is where the wider 707 fuselage tapers back into the KC-135 tail, then it goes straight aft until the tailcone.

Regarding the further-stretched 707s, I've seen models of those from the Boeing archives, they look pretty goofy.

Not sure if all of you have read "Legend and Legacy" as well as Sutter's book, both are good reads. The 367-80 wasn't quite as big of a secret as many think it was decades later, the real trick was getting USAF to short-circuit the KC-135 program to secure sales, and then turn and sell it to the airlines. There's a wonderful chapter in "Legend and Legacy," aptly named "a matter of inches," that discusses the 144" KC-135 fuselage and Douglas leapfrogging to 147. PA made a split buy, and CR Smith sat Bill Allen down and told him that they'd buy if they went to 148, so they reluctantly did, which cost about a year and gave Douglas a fighting chance to catch up. The next thing that PA and AA did was pressure Boeing into a 10-foot stretch (the original was to have the same length as the KC-135), which closed much of the passenger shortfall to the DC-8, but pissed off Qantas, who needed the lighter weight for Nadi. Boeing ended up honoring their commitment to the original-length design, with Qantas being the only customer for it.

As to why airlines bought one over the other once in full production, the edge mostly went to the 707 because it was a bit faster and had more cabin length in the 300s than the DC-8-10/20/30/40/50. Furthermore, the 707-300B/C were a bit better than the 50s in terms of payload/range, so they tended to outsell them in the 1962-65 time frame. When Douglas finally did the 62, it was a bit better on range than the 320B Advanced, but by then it was too late. The 61/63 sold well because the 707 had short gear and couldn't compete without a big rebuild, which triggered the 747. The other thing that someone alluded to was the production issues that Douglas started having in ~1966, which may have scared a few airlines into buying 707s in the late 1960s.

Lastly, because Boeing was the new kid on the block, they bent over backwards to offer customizations to people (2 TCs for AA, backward switches for TW, JT4As for Braniff, new name for a lightweight version for UA, etc.), which is why few 707s were alike. By 1963, they were somewhat more standardized, and they steadily cut down on differences throughout the generations to reduce production complexity.

Aptivaboy · Wed Dec 19, 2018 8:39 pm

Check out American's passenger -123Bs, -323Bs and -323Cs. They all have only two turbo compressors. I suspect they were the only airline that specified this during construction. It used to confuse the hell out of me as a young lad, atop the roof of T1 in YYZ, trying to identify aircraft.

Exactly! I used to fly AA's 707s all of the time back in the seventies and perhaps into the first couple of years of the eighties as a kid, and those dual turbocompressors always remained in my mind, wondering what they were. I cried when the 727s took over the for big quad...

timz · Wed Dec 19, 2018 8:52 pm

CWizard wrote:
Current jetliners are slower than the original 707, which cruised at an equivalent ground speed of 608 mph.

No idea about ground speed, but the original 707 usually cruised at Mach 0.82 or less.

longhauler · Thu Dec 20, 2018 12:26 am

TurboJet707 wrote:
All four engine nacelles have the 'knuckles' for the turbo compressors on top.
After conversion, only two of those four compressors remained

Although the air intakes sat on top all four of the nacelles of the non-fan -120s and -320s as well as the -420s, there were still only three turbo compressors, nothing on engine 1.

As you note, American had only two turbo compressors on (most of) its -123Bs and -323B/Cs. Most airlines stuck with the three after conversion to (or new build) JT3Ds.

Max Q · Thu Dec 20, 2018 4:51 am

This is the very best of A.Net

What a superb topic and associated replies by all

Love the 707, it had its design issues, some were significant but considering the era it was built in its amazing how ‘right’ Boeing got it, their experience with high speed aerodynamics on the B47 was a big advantage in developing their first commercial jet transport

The fact that its still in use by air forces around the world is a testament to its design and construction

greendot · Thu Dec 20, 2018 7:48 am

DrPaul wrote:
A question I have following on from this discussion is this: what were the salient points that encouraged airlines to buy 707s rather than DC-8s, or DC-8s rather than 707s, when they were both fully in production?

I've only recently discovered that two stretched versions of the 707 were envisaged, with 45 and 55 foot fuselage extensions, making them 197 and 207 feet long, and a 10 foot wider wing span. Now they would have been quite a sight, the ultimate 'flying pencil'.

It's odd when I think back to when I used to see 720s coming into Heathrow, I used to think that they were quite large aeroplanes; nowadays, I think that 737-800s, which are only seven feet shorter than the 720, and the 737-900s, which are two feet longer, are quite small. I suppose this perception is because the average size of airliners has increased somewhat over the last 50 or more years.

What is interesting is that the 707-320c (325k takeoff, 344k inflight) is twice the takeoff weight of an almost similar sized A321. I fly/flew both.

longhauler · Thu Dec 20, 2018 1:25 pm

I was recently reading a book about the 707/720 and an odd fact popped up. It seems the standard window size of the 707 was 9" x 12 1/2", but American specified a larger optional window sized at 10" x 14". Looking at some of the pictures, it does appear that the space between the windows is less than other airlines' 707/720s.

But, even with a library of over 1000 aviation books, I have never seens this mentioned anywhere else. Certainly never seen any mention of it online.

Anyone else heard of this?

DrPaul · Thu Dec 20, 2018 2:33 pm

greendot wrote:
DrPaul wrote:
A question I have following on from this discussion is this: what were the salient points that encouraged airlines to buy 707s rather than DC-8s, or DC-8s rather than 707s, when they were both fully in production?

I've only recently discovered that two stretched versions of the 707 were envisaged, with 45 and 55 foot fuselage extensions, making them 197 and 207 feet long, and a 10 foot wider wing span. Now they would have been quite a sight, the ultimate 'flying pencil'.

It's odd when I think back to when I used to see 720s coming into Heathrow, I used to think that they were quite large aeroplanes; nowadays, I think that 737-800s, which are only seven feet shorter than the 720, and the 737-900s, which are two feet longer, are quite small. I suppose this perception is because the average size of airliners has increased somewhat over the last 50 or more years.

What is interesting is that the 707-320c (325k takeoff, 344k inflight) is twice the takeoff weight of an almost similar sized A321. I fly/flew both.

That's a comparison that makes one think. For me, the 707 is a proper aeroplane, always an impressive sight; the A321 is a sort of 'Oh, another one of them' anonymous sort of plane. I was a little kid, about four or five years old, when I saw the first 707 coming into Heathrow, right over my house in Richmond; it was big, noisy and really scary. I can't imagine any four- or five-year-old kid being scared at the sight of an A321 over his house.

kiowa · Thu Dec 20, 2018 5:00 pm

fightforlove wrote:
American Airlines always had a close relationship with Douglas in the 30s, 40s, and 50s. AA worked with Douglas to develop airplanes and launched the DC-3, DC-6, and the DC-7. So, why did American break for the 707 over the DC-8? They also did not buy the DC-9, opting for the British BAC-111 instead. American would come back to Douglas in a big way with the DC-10 and MD-80 series, but was there something that soured the AA-Douglas relations during the 1960s? Or, was the 707 truly the better airplane for AA's needs?

To get the first hand information one can ask one of AAs senior flight attendants. They may remember the actual reasoning at the time.

TurboJet707 · Thu Dec 20, 2018 6:23 pm

Revelation wrote:
Re: 707 and stability: Previous a.net discussions pointed me to a great interview series:
The D. P. Davies Interview on testing the Comets, Boeing 707, Britannia & Brabazon.
“The test pilots’ test pilot”, former CAA Chief Test Pilot D. P. Davies talks frankly about the civil aircraft that he put through his paces before being certified as safe in the UK.
The interview was conducted by Rodney Giesler in 1992 and edited by Mike Stanberry FRAeS.

https://www.aerosociety.com/news/audio- ... the-1940s/
If the links don't work, google 'soundcloud dp davies' to get direct links.

It's safe to say he was none too impressed with the original 707 he was asked to certify.

Thanks for that link! I put it on a USB drive and will isten to it during a long drive. Great stuff I think!

TurboJet707 · Thu Dec 20, 2018 6:30 pm

longhauler wrote:
Although the air intakes sat on top all four of the nacelles of the non-fan -120s and -320s as well as the -420s, there were still only three turbo compressors, nothing on engine 1.

As you note, American had only two turbo compressors on (most of) its -123Bs and -323B/Cs. Most airlines stuck with the three after conversion to (or new build) JT3Ds.

Ah, thanks for clarifying. I learn something new every day :-)

So they went from 3 to 2.

The existence of so many little differences is one of the things that make the 707 such a fascinating aircraft to me. There were also some real oddballs among them, like the 720, the -220, the Qantas 'short-body' 138(B) and so on.

sparky35805 · Thu Dec 20, 2018 7:32 pm

The original 707 that Pan Am ordered was designed to be built with the KC-135 tooling and was only wide enough with 5 abreast.They ordered 20 to get an early start with jets.The ordered 25 JT4-A powered DC-8s for their long range airplane.Boeing lost the United order to Douglas because United wanted 6 abreast in coach.Wit American,Boeing gave in and redesigned the fuselage to be wide enough for 6 abreast.Once they did this,they stretched the fuselage and redesigned the wing to make the JT4-A powered -320.Pan Am's order was changed to 6 of the redesigned -120s for early delivery and the remaining 14 to JT-4A powered -321s.

global2 · Thu Dec 20, 2018 8:52 pm

So, I just watched the 1962 movie "That Touch of Mink" starring Doris Day and Cary Grant. There's a terrific scene with Doris boarding a Pan Am 707 at the JFK Worldport, and mid-flight scenes. The 707 in one shot turned into a DC-8 for the landing scene, and back to a 707 on the apron in Bermuda

The interior shot is definitely a 707 cabin.

TVNWZ · Thu Dec 20, 2018 9:17 pm

When did the military start buying up all the 707s?

LH707330 · Thu Dec 20, 2018 10:15 pm

TVNWZ wrote:
When did the military start buying up all the 707s?

Late 1970s and early 1980s, hence the quick removal of them from airline service. the secondary market to uncle sam killed a lot of the 707-700 business case.

BostonBeau · Thu Dec 20, 2018 10:34 pm

The B707 and DC-8 were both beautiful planes. I took a trip to Europe in 1970 where I flew a TWA 707-320B one way and a KLM DC-8-63 the other. Both were very comfortable in economy (I think the standard seat pitch was 33-34 inches at that point). The DC-8-63 was the really long version (I think in all-coach it could seat 250) and definitely had the "long thin aluminum tube" feeling about it. I next flew an American B707 to the "Transpo '72" air show that was held at the still relatively new and still relatively empty Dulles Airport in Virginia in 1972. I remember that flight because the flight attendant making announcements broke up laughing when saying "Welcome aboard American flight XXX, service to Dulles and Dallas".

greendot · Fri Dec 21, 2018 5:25 am

DrPaul wrote:
greendot wrote:
DrPaul wrote:
A question I have following on from this discussion is this: what were the salient points that encouraged airlines to buy 707s rather than DC-8s, or DC-8s rather than 707s, when they were both fully in production?

I've only recently discovered that two stretched versions of the 707 were envisaged, with 45 and 55 foot fuselage extensions, making them 197 and 207 feet long, and a 10 foot wider wing span. Now they would have been quite a sight, the ultimate 'flying pencil'.

It's odd when I think back to when I used to see 720s coming into Heathrow, I used to think that they were quite large aeroplanes; nowadays, I think that 737-800s, which are only seven feet shorter than the 720, and the 737-900s, which are two feet longer, are quite small. I suppose this perception is because the average size of airliners has increased somewhat over the last 50 or more years.

What is interesting is that the 707-320c (325k takeoff, 344k inflight) is twice the takeoff weight of an almost similar sized A321. I fly/flew both.

That's a comparison that makes one think. For me, the 707 is a proper aeroplane, always an impressive sight; the A321 is a sort of 'Oh, another one of them' anonymous sort of plane. I was a little kid, about four or five years old, when I saw the first 707 coming into Heathrow, right over my house in Richmond; it was big, noisy and really scary. I can't imagine any four- or five-year-old kid being scared at the sight of an A321 over his house.

I think the 707 looks prettier but I like the A321 a lot more. It's a newer/safer design. Airbus are well designed for pilot mental ergonomics. You have to unlearn some things but after that, it makes more logical sense since the whole aircraft is one big integrated system. But, it's an unfair comparison. It's like comparing a Mig17 to an F18. Still, I'm glad i got to fly it for as long as i did. The A340 reminds me of the 707 when i see it at the airport.

greendot · Fri Dec 21, 2018 5:30 am

TVNWZ wrote:
When did the military start buying up all the 707s?

Most were not bought from anyone but from Boeing directly. For example, USAF E-3s were being made into 1981 (approximately) at Boeing. Keep in mind that military 707s are drastically different than civilian 707s. And... a KC-135 is not a 707. Military 707s have usually either CFM56 or TF33 engines. I think the TF33 put out 21,500# per engine, which I think is twice the thrust of the original 707. Also, there's a ton of differences in the systems. For example, E-3s have 8 generators.

NOLAWildcat · Fri Dec 21, 2018 6:29 am

While you’re correct that most of USAF’s 707-based airframes (E-3, E-8, and the Navy’s E-8) were purchased directly from Boeing (some as late as 1992), if I recall correctly, Uncle Sam purchased a good chunk of the US-registered 707 fleet in the early 80’s as a spare parts source for the KC-135 fleet. With the advent of the 757, 767, and A300/310 and the enacting of tougher noise regulations, the market for used 707s was soft and the US government could buy them at very attractive prices.

While the KC-135 and the 707 are two different airframes, there is still quite a bit of commonality between the two models. For example, most turbofan-powered 707s were powered by Pratt & Whitney JT3Ds, which is the civilian designation of the TF-33s on the KC-135E, RC-135, and E-3. There are pictures on this site of rows of ex-TW and ex-AA 707s parked at Davis-Monthan AFB missing their vertical stabilizers, presumably cannibalized for use on the KC-135 fleet.

questions · Fri Dec 21, 2018 7:47 am

TurboJet707 wrote:
DL_Mech wrote:
I like to bring up this photo when a 707(720) is compared to a 737NG. Fuselage length may be similar, but a 707-100 is like a 737-800 with 767 wings!

That's a nice way to put it, and the picture clearly shows the difference.
By comparison, the 707's wings are indeed massive. Yet, neither the 737 nor the 707 looks out of proportion (but to me the 707 is a much more impressive beast!). The 707 was designed as a long-haul transport with 4 gas-guzzling Pratts, so the wings had to take a lot more fuel than those of the newer-generation 737s. In addition to that, can we say that the 737NG + MAX wing is much more efficient, requiring less area?

Can you/someone clarify? What is an efficient wing? What makes one wing more efficient than another?

timz · Fri Dec 21, 2018 6:37 pm

Guess it's easy to compare the 707 and 737 wing loadings -- gross weight divided by wing area. Offhand guess: 737 has more wing per pound of aircraft.

timz · Fri Dec 21, 2018 7:19 pm

No, usually not. Looks like a 737-800 has about 44% of the wing area of a 707-320B.

THS214 · Sat Dec 22, 2018 8:05 pm

global2 wrote:
SEPilot wrote:

So I believe I read that when Boeing expanded the width of the fuselage to accommodate six abreast seating, it ended up being six inches wider than the DC-8. I wonder how wide the seats on the DC-8 were then? I know they were quite unique in design: attached directly to the wall, middle seat slightly wider than the aisle & window, etc. I only mention this because of all the histrionics I see posted on Anet about the supposedly excruciatingly narrow seats on the 737 (same width as the 707) vs. those huge, luxurious seats on the Airbus--a whopping half inch wider. I've never read anything where people complained about seat width on the DC-8.

Remember that was like 50 years ago. Obesity was not a problem then. Flown them both and seats were fine. For me 737 and A320 seats are fine, but when having an "big" person next to me, that half an inch is a lot.

SEPilot · Sat Dec 22, 2018 8:23 pm

THS214 wrote:
global2 wrote:
SEPilot wrote:

So I believe I read that when Boeing expanded the width of the fuselage to accommodate six abreast seating, it ended up being six inches wider than the DC-8. I wonder how wide the seats on the DC-8 were then? I know they were quite unique in design: attached directly to the wall, middle seat slightly wider than the aisle & window, etc. I only mention this because of all the histrionics I see posted on Anet about the supposedly excruciatingly narrow seats on the 737 (same width as the 707) vs. those huge, luxurious seats on the Airbus--a whopping half inch wider. I've never read anything where people complained about seat width on the DC-8.

Remember that was like 50 years ago. Obesity was not a problem then. Flown them both and seats were fine. For me 737 and A320 seats are fine, but when having an "big" person next to me, that half an inch is a lot.

Other posters have said that the 707 was only 1 inch wider than the DC-8. And as you say, extremely obese people were a lot less common then.

greendot · Tue Dec 25, 2018 3:53 pm

NOLAWildcat wrote:
While you’re correct that most of USAF’s 707-based airframes (E-3, E-8, and the Navy’s E-8) were purchased directly from Boeing (some as late as 1992), if I recall correctly, Uncle Sam purchased a good chunk of the US-registered 707 fleet in the early 80’s as a spare parts source for the KC-135 fleet. With the advent of the 757, 767, and A300/310 and the enacting of tougher noise regulations, the market for used 707s was soft and the US government could buy them at very attractive prices.

While the KC-135 and the 707 are two different airframes, there is still quite a bit of commonality between the two models. For example, most turbofan-powered 707s were powered by Pratt & Whitney JT3Ds, which is the civilian designation of the TF-33s on the KC-135E, RC-135, and E-3. There are pictures on this site of rows of ex-TW and ex-AA 707s parked at Davis-Monthan AFB missing their vertical stabilizers, presumably cannibalized for use on the KC-135 fleet.

Did KC-135's have TF-33s? I don't remember what they had but I know they have CFM-56s now and previously they might have had something with around half the thrust of a TF-33.

longhauler · Tue Dec 25, 2018 4:11 pm

SEPilot wrote:
Other posters have said that the 707 was only 1 inch wider than the DC-8. And as you say, extremely obese people were a lot less common then.

It is one inch wider on the outside, but about half an inch wider on the inside.

But ... a part of the cabin design of the early DC-8s with the Palomar seats, is that the outboard seat attachment was to the wall, the seat did not have an outboard armrest as it was on the wall with the attachment, which was also the lower attachment for the curtain. As a result, that 1 1/2 inch wide outboard armrest figured into the cabin width on the DC-8, but would not on the 707 where the armrests were on the seat. This made the DC-8 seats slightly wider than the 707 seats.

With the introduction of the 2nd generation interior of the DC-8-60s (and Air Canada's DC-8-53s) the seats were more "conventional" with the wall armrest gone and thinner cabin walls used. This made the DC-8 cabin wider than the 707 cabin.

Spacepope · Tue Dec 25, 2018 4:44 pm

greendot wrote:
NOLAWildcat wrote:
While you’re correct that most of USAF’s 707-based airframes (E-3, E-8, and the Navy’s E-8) were purchased directly from Boeing (some as late as 1992), if I recall correctly, Uncle Sam purchased a good chunk of the US-registered 707 fleet in the early 80’s as a spare parts source for the KC-135 fleet. With the advent of the 757, 767, and A300/310 and the enacting of tougher noise regulations, the market for used 707s was soft and the US government could buy them at very attractive prices.

While the KC-135 and the 707 are two different airframes, there is still quite a bit of commonality between the two models. For example, most turbofan-powered 707s were powered by Pratt & Whitney JT3Ds, which is the civilian designation of the TF-33s on the KC-135E, RC-135, and E-3. There are pictures on this site of rows of ex-TW and ex-AA 707s parked at Davis-Monthan AFB missing their vertical stabilizers, presumably cannibalized for use on the KC-135 fleet.

Did KC-135's have TF-33s? I don't remember what they had but I know they have CFM-56s now and previously they might have had something with around half the thrust of a TF-33.

Yes. Some models (such as the RC-135B) were delivered from the factory with TF-33s and are still in service in that config as the Open Skies airframe. Other ones were converted as the KC-135 D/E models, which is where a lot of the JT3D engines and pylons of commercial 707s went. All the E-8s (JSTARS) were purchased secondhand for the air force, but the Navy's E-6 fleet was new-build. The USAF also operated 707s as TC-18 trainers for aircrew to keep the hours down on the E-3 fleet (and you really don't need to do touch and goes with a real E-3).

ClipperMonsoon · Tue Dec 25, 2018 4:49 pm

Greendot[/quote]
What is interesting is that the 707-320c (325k takeoff, 344k inflight) is twice the takeoff weight of an almost similar sized A321. I fly/flew both.[/quote]

B707320C adv model max tow was 336,000 lbs with either -3b or -7 engines, with Comtran hush kits this reduced mtow to 322,300 lbs due to noise, mlw reamained at 247, 000 lbs, however this was with 30 flaps as 50 flaps was only to be used in an emergency, keep in mind this was for USA ops, as other hushkitted aircrafts in other parts of the world still used 50 flaps for landing, never heard off 344,000 in flight, how could max takeoff be lower than in flight weight, never heard of this in many years working with un and hushkitted 707s. Just adding some info that I'm aware of.

Spacepope · Tue Dec 25, 2018 8:17 pm

ClipperMonsoon wrote:
Greendot

never heard off 344,000 in flight, how could max takeoff be lower than in flight weight, never heard of this in many years working with un and hushkitted 707s. Just adding some info that I'm aware of.[/quote]

I think that ties into a thread we have on Mil-av about military versions tanking up over MTOW after takeoff.

zippyjet · Wed Dec 26, 2018 12:10 am

SEPilot wrote:
The 707 caught Douglas completely flat footed. They had committed to the DC-7 before they knew about the 707, and so had to hurry the DC-8 proposal, and were a year behind getting it to market. Boeing had put a couple of years into development before revealing it, research that Douglas was unable to replicate. The one advantage Douglas had was that, by coming second, they were able to “one-up” Boeing by making theirs 6 abreast (the 707 was originally 5 abreast) which won orders from a couple of major airlines, one of them United. Boeing had been there before, with the 247, and did not want a repeat. There was powerful disincentive to change the fuselage as they were already making KC-135s and couldn’t change them and hence would need two sets of tooling where they had planned on only one. But at a Bill Allen’s insistence they went ahead and made the 707 6 abreast. But on top of that, Boeing had extensive experience with large jets with the B-47 and B-52, and Douglas did not, and Boeing had their own high speed wind tunnel, which Douglas did not. The result was the high altitude high speed performance of the 707 was always better than the DC-8. It is notable that Pan Am, which is one of the few airlines to buy both planes did not keep their DC-8s long but ordered boatloads of 707s.

Talk about flat footed. Lockheed bet the farm on Turbo Props with the L188. Had that one come out 5 years earlier Lockheed may have sowed the seeds to stay in the commercial airliner business. Interesting that AA went with L188's. Not to hijack the thread but why, did National Air Lines go with the DC-8 same with Eastern. Both of them set themselves back a year. Had the 720 come out earlier do you think Eastern and National would have gone with them over the Electra and DC-8? National never went for 720's And I pose this issue because, National leased 707's from Pan Am for the lucrative New York and Chicago to Miami routes.

ClipperMonsoon · Wed Dec 26, 2018 12:56 am

Spacepope wrote:
ClipperMonsoon wrote:
Greendot
never heard off 344,000 in flight, how could max takeoff be lower than in flight weight, never heard of this in many years working with un and hushkitted 707s. Just adding some info that I'm aware of.

I think that ties into a thread we have on Mil-av about military versions tanking up over MTOW after takeoff.[/quote]

Same thing I was thinking too, but the thread was started about commercial 707's, so my reference was just to civil 707's

Spacepope · Wed Dec 26, 2018 1:06 am

zippyjet wrote:
SEPilot wrote:
The 707 caught Douglas completely flat footed. They had committed to the DC-7 before they knew about the 707, and so had to hurry the DC-8 proposal, and were a year behind getting it to market. Boeing had put a couple of years into development before revealing it, research that Douglas was unable to replicate. The one advantage Douglas had was that, by coming second, they were able to “one-up” Boeing by making theirs 6 abreast (the 707 was originally 5 abreast) which won orders from a couple of major airlines, one of them United. Boeing had been there before, with the 247, and did not want a repeat. There was powerful disincentive to change the fuselage as they were already making KC-135s and couldn’t change them and hence would need two sets of tooling where they had planned on only one. But at a Bill Allen’s insistence they went ahead and made the 707 6 abreast. But on top of that, Boeing had extensive experience with large jets with the B-47 and B-52, and Douglas did not, and Boeing had their own high speed wind tunnel, which Douglas did not. The result was the high altitude high speed performance of the 707 was always better than the DC-8. It is notable that Pan Am, which is one of the few airlines to buy both planes did not keep their DC-8s long but ordered boatloads of 707s.

Talk about flat footed. Lockheed bet the farm on Turbo Props with the L188. Had that one come out 5 years earlier Lockheed may have sowed the seeds to stay in the commercial airliner business. Interesting that AA went with L188's. Not to hijack the thread but why, did National Air Lines go with the DC-8 same with Eastern. Both of them set themselves back a year. Had the 720 come out earlier do you think Eastern and National would have gone with them over the Electra and DC-8? National never went for 720's And I pose this issue because, National leased 707's from Pan Am for the lucrative New York and Chicago to Miami routes.

I think Lockheed’s issue with this generation of jets stems from the tanker project. They actually WON the competition and the 717/KC-135 was only adopted as the interim tanker till the Lockheed model was ready. Lockheed never got their tanker to production and history was written at that point. Not sure how the competition on the civil side would have shaken out though, probably dooming the Convair offerings even sooner and we’d have never gotten the 990.

Runway28L · Wed Dec 26, 2018 1:35 am

greendot wrote:
NOLAWildcat wrote:
While you’re correct that most of USAF’s 707-based airframes (E-3, E-8, and the Navy’s E-8) were purchased directly from Boeing (some as late as 1992), if I recall correctly, Uncle Sam purchased a good chunk of the US-registered 707 fleet in the early 80’s as a spare parts source for the KC-135 fleet. With the advent of the 757, 767, and A300/310 and the enacting of tougher noise regulations, the market for used 707s was soft and the US government could buy them at very attractive prices.

While the KC-135 and the 707 are two different airframes, there is still quite a bit of commonality between the two models. For example, most turbofan-powered 707s were powered by Pratt & Whitney JT3Ds, which is the civilian designation of the TF-33s on the KC-135E, RC-135, and E-3. There are pictures on this site of rows of ex-TW and ex-AA 707s parked at Davis-Monthan AFB missing their vertical stabilizers, presumably cannibalized for use on the KC-135 fleet.

Did KC-135's have TF-33s? I don't remember what they had but I know they have CFM-56s now and previously they might have had something with around half the thrust of a TF-33.

All of the original KC-135s (The A and then Q models) had P&W J-57 turbojets. At around the late 70s, a number of A models were converted to KC-135E standard, which involved the conversion to the TF-33 turbofans. It was then in the early to mid 80s that the KC-135Es and the remaining KC-135A/Qs began to undergo the CFM-56 mod.

IINM, the CFM-56 re-engine program was completed in 2005. The last A and Q models were converted/retired in the mid 90s and the last KC-135E was retired in 2009.

The whole mod program went as follows:
KC-135A > E > R
KC-135A > R
KC-135Q > T (these are the variants that have special plumbing installed to carry the SR-71’s fuel separately)

spartanmjf · Wed Dec 26, 2018 2:31 am

In reading the last couple of posts I was reminded of some reading I did years ago that mentioned the Lockheed tanker/airliner project which was designated as the L-193. The design concept was similar to what would become the VC-10 and IL-62. The decision process that led Lockheed to not pursue this design would be interesting to understand.

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