Why Did Boeing Build The 727?

727LOVER · Wed Apr 25, 2012 12:45 am

Don't get me wrong, as my username says, I LOOOOOOOOVE the 727. But looking at the 737 fro the rest of our lived thread, and all the gushing over that plane, why didn't Boeing just make a small/mid size two engine, two pilot aircraft for shorter runways in the first place.The 737 has all this longevity because in later years, it filled the 727's role.

Thoughts?

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tymnbalewne · Wed Apr 25, 2012 1:19 am

The very short, very inadequate answer is that UA, AA and EA all wanted an airliner to serve smaller cities. UA wanted 4 engines for high altitude airports, AA wanted two engines, and EA wanted three for their overwater flights to the Caribbean, (this was well before ETOPS!).
So, the best compromise was, in fact 3 engines, hence the 727.

rampart · Wed Apr 25, 2012 1:50 am

At the time the 727 was conceived, late 1950s, crew of 3 was normal, 3 engines were deemed necessary, and the size of the plane was a step lower than the 707, yet bigger than the DC-9 which was also developing. Only later did Boeing think they needed a smaller jet, which became the 737. They had no intention of growing the 737 to what it is now. Remember, up through the early 1990s, the 727 was the world's best selling airliner, over 1800 built. By that time, the 737 was refreshed and extended, and it took over that role, more than 25 years after it was conceived. The 727 had also planned to refresh and expand, but that became the 757 on the high end, and the 737-300 on the lower end.

-Rampart

sstsomeday · Wed Apr 25, 2012 2:34 am

Quoting rampart (Reply 2):
The 727 had also planned to refresh and expand, but that became the 757 on the high end, and the 737-300 on the lower end.

Yes - And the 727 was not able to evolve the way the 737 could, as in high-bypass turbofan engines, because of the nature of the engine configuration (Fuselage-mounted engines; middle engine intake through the fuselage, etc.)

Incidentally, the 727 was initially designed to replace a number of 4-prop airliners at the time, such as the DC-6/7 I think, and in Canada the Vickers Viscount and Vanguard, etc. 2 Engine technology for airliners was evolving at that time and not common. Engines were not nearly so reliable and therefore safety was more directly dependant on redundancy.

rampart · Wed Apr 25, 2012 2:55 am

Quoting SSTsomeday (Reply 3):
Yes - And the 727 was not able to evolve the way the 737 could, as in high-bypass turbofan engines, because of the nature of the engine configuration (Fuselage-mounted engines; middle engine intake through the fuselage, etc.)

There were proposals for a twin 727, minus the middle engine. While I can't recall if these were supposed to be the upcoming higher-bypass CFM engines -- they might have been -- it would have been possible to do that, theoretically. (BAe were planning the same for an extended One-Eleven.) Of course, Lockheed managed a high bypass engine with an S-duct in the tail, but that would have entailed more significant re-engineering on a 727. At any rate, as you say, Boeing realized that it was easier to extend and re-engine the 737 than it was to develop a 727 twin.

-Rampart

Stitch · Wed Apr 25, 2012 3:17 am

Quoting rampart (Reply 2):
At the time the 727 was conceived, late 1950s, crew of 3 was normal, 3 engines were deemed necessary, and the size of the plane was a step lower than the 707, yet bigger than the DC-9 which was also developing.

Quoting rampart (Reply 4):
There were proposals for a twin 727, minus the middle engine.

The concept I have seen had the engines below the wing (they look like P&W JT3C turbojets).

ADent · Wed Apr 25, 2012 4:01 am

The 727-200 is quite a bit bigger than the 737-200.

So either someone had to create a more powerful engine or you had to go with 3 engines.

No one did the first, so Boeing had to go with the second.

Douglas didn't get a twin engine (DC-9 Super 80) in the same class until 1979.

frmrCapCadet · Wed Apr 25, 2012 4:01 am

At the time the 727 was a far more capable plane - range and capacity. The 737 just kept increasing in capability.

lightsaber · Wed Apr 25, 2012 4:32 am

For over a decade the 727 was the most produced airliner. I think Boeing made the right market call.

It wasn't until 30 years into 737 production that more of them were produced than the 727! That took a re-engine too! Per Wikipedia's article on the 727, there were 250 of them flying in August 2011. Not bad for a plane with EIS in 1964. Consider that the last 727 was delivered in 1984. The youngest model is 28 years old and yet they're still flying!

Quoting 727LOVER (Thread starter):
why didn't Boeing just make a small/mid size two engine, two pilot aircraft for shorter runways in the first place.

The initial expected market for the 737/DC-9 was pretty small. Not to mention the range expectations. It is ironic that the 727 developed the market to make the 737-200 a success. But even then, the 727-200 out-delivered the 737 in 1978-1980. Much of what we consider the 737 success happened with the 733/734/735 and the engines 25% drop in fuel burn.

Now some was teething issues. The original 731s had thrust reverser issues. There was also extensive rework done on the flaps. And recall (from Wikipedia):
"In 1970, Boeing received only 37 orders. Facing financial difficulties, Boeing considered closing the 737 production-line and selling the design to Japanese aviation companies."

The early business case on the 737 wasn't strong. Recall no US airline was a launch customer (a first for Boeing) while Eastern (and others) were strong proponents for the 727. This is a case where the market matured to make the type a success.

Lightsaber

JoeCanuck · Wed Apr 25, 2012 4:43 am

They were made because they deserved to be made.

I'll get a fight from the Concorde folk but the 727 is the best looking airliner of all time. I remember flying those into YEV on a regular basis...and how damned loud the things were from the ground. We could hear them clearly from town, a full 8 miles away...and at -40ish, they sounded more like 8 blocks away.

lasairlinerenth · Wed Apr 25, 2012 6:00 am

Quoting JoeCanuck (Reply 9):
the 727 is the best looking airliner of all time

I will wholeheartedly second this sentiment. Some forty-odd years ago, I fell in love with the 727 the first time I saw one; since I was only five or six years old at the time, my best guess is it would have been an Eastern Airlines 727 that one of my uncles and his family took from Syracuse, New York to San Antonio, Texas.

I would not get to ride on my first 727 until July 1979, when I flew American Airlines from Ontario, CA to Syracuse, NY and back, with a change of plane in ORD in both directions, of course. I must have been twelve or thirteen at the time and traveling as an unaccompanied minor. LOVED IT!

My last ride on a 727 was a comparatively short United Airlines flight from Denver (DIA) to Ontario in September 1996.

Ah, memories. While I love the 737, the 727 will always have a special place in my heart.

rampart · Wed Apr 25, 2012 7:12 am

Quoting Stitch (Reply 5):
The concept I have seen had the engines below the wing (they look like P&W JT3C turbojets).

Yes. If you are thinking of the post-727 redevelopment, with the high bypass engines became the 7N7. I also recall a model (I believe it was in AW&ST) that had the 2 rear-mounted engines, this was mid-70s. Maybe they were low bypass, but I don't think they were late generation (1960s?) turbojets. You might also be thinking of some early models proposed for the first 727, some of which look more like a DC-9, and some which had the T-tail and engines on the wing. There are also early 737 concepts that looked very much like the DC-9. There was a thread on A.net a few months back on the Boeing archive displaying these models, but some of the models are visible here: http://airchive.com/html/museums/boe...g-archives-bellevue-washington-usa

Actually, on that same website I just found a picture of the "727-300" concept with the engines I recall seeing in AW&ST. Rear-mounted, twin, high bypass:
http://airchive.com/html/museums/boe...-300-model-circa-early-1970s/19069
The FLighGlobal archives say that various versions of the 727-300 were offered to UA and BN, who were interested, but then began to favor an all-new airplane, which became the 7N7 (then the 757).

Earlier someone had commented on the difficulty of using high bypass engines in the center-mounted tail. I forgot that the 7X7 had this configuration (as well as the Tristar), a trijet widebody first with a T-tail, then a conventional tail, then late in the design process dropped the 3rd engine to become 767.

-Rampart

rampart · Wed Apr 25, 2012 7:34 am

Sorry to add on here, but everyone should find this 1960 article from Flight very interesting! "Boeing's Trimotor: Background to the development of the 727." There are 3-view sillhouetes of various twin-, tri-, and quad-jet concepts of the 727, some with conventional tails, some with t-tails, some with cruciform tails. Also gives the history of the market analysis, and comparisons to the Trident. Within all this concept was also the idea of a smallish jet that was revived to become the 737. But 1960 technology, as we've said, required the 727 first, and it dominated for more than 2 decades.
http://www.flightglobal.com/pdfarchive/view/1960/1960%20-%203094.html

-Rampart

columba · Wed Apr 25, 2012 8:37 am

Quoting rampart (Reply 2):
Only later did Boeing think they needed a smaller jet, which became the 737.

Only later Boeing was pushed by LH into developing the 737.

The 727 was the right aircraft back then and a true success, the first jet airliner that had reached the magic number of 1000 aircraft being produced. Not to mention that it is indeed is the most beautiful jetliner ever build.

AirbusA370 · Wed Apr 25, 2012 8:43 am

And, why didn't the name it this way:

727 -> Two Engines (instead 737)
737 -> Three Engines (instead 727)
747 -> Four Engines (well, correct)

MD11Engineer · Wed Apr 25, 2012 8:48 am

Quoting AirbusA370 (Reply 14):
And, why didn't the name it this way:

727 -> Two Engines (instead 737)
737 -> Three Engines (instead 727)
747 -> Four Engines (well, correct)

And the 707 was a glider, right?

Jan

ghifty · Wed Apr 25, 2012 9:39 am

How much commonality is there between the 727 and 737? It's just the same fuselage cross-section and nose, right?

Quoting AirbusA370 (Reply 14):
And, why didn't the name it this way:

727 -> Two Engines (instead 737)
737 -> Three Engines (instead 727)
747 -> Four Engines (well, correct)

Haha, good laugh.

A340 -> 4 engines
A320 -> 2 engines
A330 -> Trijet!
A380 -> 8 engines!
...
A310 -> 1 engine
A300 -> 0?

L-1011..

Quoting lightsaber (Reply 8):
"In 1970, Boeing received only 37 orders. Facing financial difficulties, Boeing considered closing the 737 production-line and selling the design to Japanese aviation companies."

I'm not questioning the legitimacy of that quote, but what's the actual source?.. might lead to more aviation trivia!

Faro · Wed Apr 25, 2012 10:09 am

Quoting tymnbalewne (Reply 1):
The very short, very inadequate answer is that UA, AA and EA all wanted an airliner to serve smaller cities. UA wanted 4 engines for high altitude airports, AA wanted two engines, and EA wanted three for their overwater flights to the Caribbean, (this was well before ETOPS!).
So, the best compromise was, in fact 3 engines, hence the 727.

Airframe development is often directly tributary of engine development.

A complement to your short answer is that there wasn't at the time an engine capable of powering a 727-like aircraft as a twin, or in any case an engine with low enough fuel burn.

Faro

BritishB747 · Wed Apr 25, 2012 10:12 am

Was the Boeing B727-100 not very similar to the original proposal for the Hawker Siddeley Trident? Hawker Siddeley even invited Boeing designers over to look at the plans for this amazing new aircraft that they had designed. Then BEA decided to change their requirements and the Trident became another disaster for the British aircraft industry and Boeing unveiled an aircraft more or less identical to the original specification Trident. Amazing the stupidity of HS inviting a rival to look at the plans for their aircraft.

HAWK21M · Wed Apr 25, 2012 10:13 am

Quoting MD11Engineer (Reply 15):

Nice one.....

aircraft type naming is not so simple & straight

Although I still wonder why the B717 model name was NOT utilised commercially until much later.

ebj1248650 · Wed Apr 25, 2012 10:21 am

Quoting rampart (Reply 4):
There were proposals for a twin 727, minus the middle engine.

As I recall, American Airlines was a potential customer for this. The middle engine would have been removed and the middle air intake duct would have been faired over. I don't recall what engines were planned for the fuselage stations.

columba · Wed Apr 25, 2012 10:25 am

Quoting HAWK21M (Reply 19):
Although I still wonder why the B717 model name was NOT utilised commercially until much later.

The real 717 is the KC-135, I wonder more about the 720

Clydenairways · Wed Apr 25, 2012 10:42 am

As others have pointed out, technology was not available when the 727 was conceived, to make an aircraft of that size and performance with only 2 engines and a 2 man cockpit. And regulations also prohibited it, as engines and systems were much less reliable, and new technologies and automation had to be proven.The success of the 727 paved the way for the 737 to happen.

The 737 came many years later during a time in the late 60's, a time when technology was developing at a rapid rate.
And It was only in the Mid/late '80's thet the later evolutions of the 737 were able to replace the earlier 727's.
The larger 727 models were replaced initially by the 757 and it was not until the 737-800 was developed, that a true 727-200 replacement was built by Boeing.

Also the 727 name could have lived on had the 757 been called the 727-300. Sure the 737 Max will have very little in common with the original 737, so what's in a name really.

einsteinboricua · Wed Apr 25, 2012 11:31 am

Quoting AirbusA370 (Reply 14):

And, why didn't the name it this way:

727 -> Two Engines (instead 737)
737 -> Three Engines (instead 727)
747 -> Four Engines (well, correct)

Hahaha good one, but like Airbus, Boeing gives the next designation in line. Since the 727 was the second jet developed (after skipping the 717 reserved for the KC-135), it was given it. Subsequent jets also follow the same pattern.

warden145 · Wed Apr 25, 2012 11:51 am

Quoting columba (Reply 21):
I wonder more about the 720

Someone who knows for sure will certainly correct me

but IIRC the premise behind that was UA wanting to order a smaller variant of the 707 but not wanting to be seen as ordering 707's (can't remember if that was because they didn't want to get Douglas riled up or if it had something to do with saving face at the BoD meeting), so Boeing changed the model number to secure the order...or something like that

crash65 · Wed Apr 25, 2012 12:16 pm

I have found the wikipedias of the respective aircraft to be very informative. Give them a try.

http://en.wikipedia.org/wiki/Boeing_727

mbj2000 · Wed Apr 25, 2012 12:19 pm

Quoting BritishB747 (Reply 18):
Was the Boeing B727-100 not very similar to the original proposal for the Hawker Siddeley Trident? Hawker Siddeley even invited Boeing designers over to look at the plans for this amazing new aircraft that they had designed. Then BEA decided to change their requirements and the Trident became another disaster for the British aircraft industry and Boeing unveiled an aircraft more or less identical to the original specification Trident. Amazing the stupidity of HS inviting a rival to look at the plans for their aircraft.

I was asking myself the same question. The Trident was in fact the "original" design... Maybe the british engineers at that time still believed in fairplay in the aircraft business...

Clydenairways · Wed Apr 25, 2012 12:26 pm

Quoting BritishB747 (Reply 18):
Was the Boeing B727-100 not very similar to the original proposal for the Hawker Siddeley Trident? Hawker Siddeley even invited Boeing designers over to look at the plans for this amazing new aircraft that they had designed. Then BEA decided to change their requirements and the Trident became another disaster for the British aircraft industry and Boeing unveiled an aircraft more or less identical to the original specification Trident. Amazing the stupidity of HS inviting a rival to look at the plans for their aircraft.

Well you have to look at this with the perspectine of Post WW2 era and the relationship between the two countries, and there are plenty of other examples of this "one way transfer".

But even saying that, i don't think the final outcome would have been anything different.

tockeyhockey · Wed Apr 25, 2012 1:01 pm

what was the relationship, if any, between the 727 and the caravelle?

Clydenairways · Wed Apr 25, 2012 1:14 pm

Quoting tockeyhockey (Reply 28):
what was the relationship, if any, between the 727 and the caravelle?

Douglas considered teaming up with SUD Aviation to build the caravelle with GE angines but they went with the DC9 in the end.

railker · Wed Apr 25, 2012 1:39 pm

Quoting einsteinboricua (Reply 23):
Hahaha good one, but like Airbus, Boeing gives the next designation in line. Since the 727 was the second jet developed (after skipping the 717 reserved for the KC-135), it was given it. Subsequent jets also follow the same pattern.

Indeed, otherwise the B-52 would've had the Boeing 787 title a long time ago, assuming the military planes are allowed in the sandbox.

SP90 · Wed Apr 25, 2012 2:16 pm

Why was the KC-135 given the 717 designation? Everything I could find on the 717 points to the re-badged MD-95. Was it Boeing policy at the time to just give it the next number on the list or was this a special case since its a military design based on the civilian 707? Was it just an internal naming for housekeeping purposes I mean they had to call it something during development I suppose.

JAAlbert · Wed Apr 25, 2012 2:18 pm

Quoting JoeCanuck (Reply 9):
remember flying those into YEV on a regular basis...and how damned loud the things were from the ground.

Remember when Eastern Airlines referred to its 727s as "Whisper Jets"? That always cracked me up.

I agree the 727's shape is iconic. It screams 60's style.

PHLBOS · Wed Apr 25, 2012 2:39 pm

Quoting ADent (Reply 6):
The 727-200 is quite a bit bigger than the 737-200.

True, but one thing to keep in mind is that the entire 727 family included the original and shorter 727-100 series as well, which rolled out about 3 years earlier than its larger -200 cousin.

Quoting rampart (Reply 2):
Remember, up through the early 1990s, the 727 was the world's best selling airliner, over 1800 built.

I'm assuming that number includes all 727 variants (-100 & -200).

lightsaber · Wed Apr 25, 2012 2:43 pm

Quoting ghifty (Reply 16):
I'm not questioning the legitimacy of that quote, but what's the actual source?.. might lead to more aviation trivia!

Pulled from the wikipedia Boeing 737 page, but this was the ultimate source:
http://www.seattlepi.com/default/art...livers-its-5-000th-737-1195654.php

Pratt ditched the JT10D as 737 sales were too poor to justify further investment and instead focused on the PW2000 for the 757. Oops.

Lightsaber

YULWinterSkies · Wed Apr 25, 2012 3:24 pm

Quoting 727LOVER (Thread starter):
But looking at the 737 fro the rest of our lived thread, and all the gushing over that plane, why didn't Boeing just make a small/mid size two engine, two pilot aircraft for shorter runways in the first place.

As others have said, technology was not yet available. Airbus faced that exact same problem in the late 80's while developing the A330 and A340. Now, the same fate as the 727 happens to the A340 which is outsold and outperformed on 90% of its missions by the A330. To paraphrase you, don't get me wrong, i LOOOOOVE the A340. But technology evolves and that is fine.

CALTECH · Wed Apr 25, 2012 3:49 pm

Always liked this version,.....

Tan Flyr · Wed Apr 25, 2012 3:53 pm

Quoting JAAlbert (Reply 32):
Remember when Eastern Airlines referred to its 727s as "Whisper Jets"? That always cracked me up.

Well compared to the B720's or the early DC-8's, they were slightly more quiet.

Unless I have missed it..no one mentioned the other reason for the 727..IIRC both UA/EA both told boeing they needed a jet that could take off from LGA fully loaded and make a 2 hour trip.(or something close to that) AA also reiterated this requirment. So the 727-100 originally had to meet the LGA (and later DCA) runway length issues. Also, carriers wanted to bring jet service to more medium or medium/large cites and routes from them for competititve reasons.

The DC-9 -10 series enabled carries such as EA/ TW/ OZ /NC to bring even more jet service to smaller communities.

When the 72S came along in 1967 (lead sleds!!) I believe they were weight restricted on very hot days at airports of any significant elevation or runway length issues. The 72A with higher thrust Pratts solved that issue in 71 or 72 as I recall.

The reduced weight of the 737 made it competitieve to the DC9-30 and soon after UA saw the success LH was having, jumped on board with a 60 frame order.

Hope my 2 cents worth here helps fill in a few blanks.

BoeingGuy · Wed Apr 25, 2012 3:55 pm

Quoting AirbusA370 (Reply 14):
And, why didn't the name it this way:

727 -> Two Engines (instead 737)
737 -> Three Engines (instead 727)
747 -> Four Engines (well, correct)

As other posters have indicated, Boeing went in order of development. The 707 came first. The 787 is the most recent. It remains to be seen what the 797 will be, or what any subsequent new models will be designated (808?).

Quoting SP90 (Reply 31):
Why was the KC-135 given the 717 designation? Everything I could find on the 717 points to the re-badged MD-95. Was it Boeing policy at the time to just give it the next number on the list or was this a special case since its a military design based on the civilian 707? Was it just an internal naming for housekeeping purposes I mean they had to call it something during development I suppose.

The KC-135 was intended to be designated the 717, but that never officially caught on. Thus, when Boeing bought out McDD and at first intended to keep the MD-95 in production, they wanted to rename it into a Boeing model series. 717 was still available. The MD-80/90/11 were not kept in production for very long so were never renamed to a Boeing-heritage model number.

Quoting JAAlbert (Reply 32):
Remember when Eastern Airlines referred to its 727s as "Whisper Jets"? That always cracked me up.

They were quiet compared to turbojet 707s are DC-8s. In today's world when we have airplanes like the 787, Whisper Jet may seem comical for the 727. But compared to older jets, it was relatively quiet.

85027 · Wed Apr 25, 2012 4:02 pm

Quoting SP90 (Reply 31):
Why was the KC-135 given the 717 designation? Everything I could find on the 717 points to the re-badged MD-95. Was it Boeing policy at the time to just give it the next number on the list or was this a special case since its a military design based on the civilian 707? Was it just an internal naming for housekeeping purposes I mean they had to call it something during development I suppose.

I have books about the 707's and the KC-135's, when the numbering of the 720 was taking place... there was actually a "paranoia" or "superstition" about the number 717 and the number being a "teen", so that is why the airlines went with the 720. It was not a new 7 series, just a modified 707, that is why it did not get the 727 numbering at the time. The military did not care or have concern of the superstitions of the "teen" and as seen today the KC-135 is still going strong!

Also, the KC-135 was not a variant of the civlian 707 but was a variation of the original 367-80; it's thoroughly a whole different airlplane and entered service prior to the 707. It's fuselage width and length, wings, landing gear, flaps, leading edge flaps, and even the hydraulic systems are different. However to save $, Boeing did keep the empenage/tail and the cockpit similar for production costs and the Air Force is using old 707's as spares for these parts at the Davis-Monthan AFB boneyard.

When Boeing bought out MDC in 1995, the MD-95 (DC-9-95) was being introduced at that time, and so Boeing put thier label on it and called the 717-200 (not the one hundred since that was already taken). By this time, airlines did not worry about those long overdue superstitions in the "teen" numbering.

BoeingGuy · Wed Apr 25, 2012 4:24 pm

Quoting 135mech (Reply 39):
I have books about the 707's and the KC-135's, when the numbering of the 720 was taking place... there was actually a "paranoia" or "superstition" about the number 717 and the number being a "teen", so that is why the airlines went with the 720.

Not correct. The 720 was named due to a political issue with UA. UA choose the DC-8 over the 707 originally for its longer haul routes. Then Boeing introduced the shorter haul 707-020. UA wanted it for shorter routes like SEA-SFO and SFO-DEN. However, UA didn't want to go to their Board of Directors requesting now to purchase 707s, after already selecting the DC-8. They didn't want to appear that they made a mistake or slap Douglas in the face (UA intended the DC-8s and 707-020s to serve different missions).

UA told Boeing that if they called the 707-020 the "720" and make it sound like an all new airplane, they'd buy some. Thus the 720 was born.

RKSofACinUSA · Wed Apr 25, 2012 4:31 pm

Though I understand and respect the place that the 727 held in aviation history, I don't have too many fond memories of it. The memories that sticks with me are sitting in the back of a loaded 727-200 on hot summer days in Tampa wondering if that back heavy plane was ever going to lift off the 10,000 ft. runway. Many times I held my breath going over Hillsborough Avenue at a very low altitude saying to myself "lift baby lift!".

85027 · Wed Apr 25, 2012 4:37 pm

Quoting BoeingGuy (Reply 40):
Not correct. The 720 was named due to a political issue with UA. UA choose the DC-8 over the 707 originally for its longer haul routes. Then Boeing introduced the shorter haul 707-020. UA wanted it for shorter routes like SEA-SFO and SFO-DEN. However, UA didn't want to go to their Board of Directors requesting now to purchase 707s, after already selecting the DC-8. They didn't want to appear that they made a mistake or slap Douglas in the face (UA intended the DC-8s and 707-020s to serve different missions).

UA told Boeing that if they called the 707-020 the "720" and make it sound like an all new airplane, they'd buy some. Thus the 720 was born.

Cool for the update, however there WAS a superstition of a "teen" number written in the books you can buy on the 707's.

connies4ever · Wed Apr 25, 2012 4:45 pm

Quoting SSTsomeday (Reply 3):
Incidentally, the 727 was initially designed to replace a number of 4-prop airliners at the time, such as the DC-6/7 I think, and in Canada the Vickers Viscount and Vanguard, etc. 2 Engine technology for airliners was evolving at that time and not common. Engines were not nearly so reliable and therefore safety was more directly dependant on redundancy.

The Viscount replacement (for AC anyway) was the outcome of an evaluation of the DC-9-10 (initially), the BAC 1-11, and (briefly) the Sud Caravelle (probably the Srs 10). Sud tried to sweeten the deal by offering license production at Canadair in Montreal, but really, by late 1960s it was a comparative dog. The 1-11, while a nice niche a/c was a) too small, and b) too short-legged for AC's liking. Woefully underpowered as well.

Quoting rampart (Reply 4):
Of course, Lockheed managed a high bypass engine with an S-duct in the tail, but that would have entailed more significant re-engineering on a 727. A

An interesting thing to keep in mind with centre-line engined a/c is the middle engine performance penalty where the engine is buried in the fuse (unlike the DC-10/MD-11). Going through an S-duct like on the 727 & L-1011 results in a flow velocity reduction that amounts to, depending on the design, an 18-20% mass flow reduction and consequent loss of thrust. One of the reasons you don't see this sort of design anymore -- also the fact the high BP engines have just gotten so much bigger and more reliable.

Quoting BritishB747 (Reply 18):
Was the Boeing B727-100 not very similar to the original proposal for the Hawker Siddeley Trident? Hawker Siddeley even invited Boeing designers over to look at the plans for this amazing new aircraft that they had designed. Then BEA decided to change their requirements and the Trident became another disaster for the British aircraft industry and Boeing unveiled an aircraft more or less identical to the original specification Trident. Amazing the stupidity of HS inviting a rival to look at the plans for their aircraft.

BEA I believe wanted something 727-sized initially, but as you indicated revised the requirements to make the a/c "tuned" for European routes. Which resulted in HS producing a niche a/c that very few other airlines actually wanted. Actually, if BEA had had their way I think they would simply have purchased the 727-100.

Quoting columba (Reply 21):
The real 717 is the KC-135, I wonder more about the 720

I can't remember the name, but the chairman of UA at the time was bound and determined that UA would not be seen to be ordering 707s of any series after purchasing 40 DC-8s. So, the 707-020 (as it was then known) became the 720. Possibly justified since the wing is different and the fuse is I think about 13 ft shorter.

Quoting BoeingGuy (Reply 38):
The KC-135 was intended to be designated the 717, but that never officially caught on.

Quoting 135mech (Reply 39):
I have books about the 707's and the KC-135's, when the numbering of the 720 was taking place... there was actually a "paranoia" or "superstition" about the number 717 and the number being a "teen", so that is why the airlines went with the 720.

Actually it is a 717. IIRC in the entrance area it states Boeing Model 717 on every C-135, whatever variant. This is likely a reference to the design study.

BoeingGuy · Wed Apr 25, 2012 4:50 pm

Quoting 135mech (Reply 42):
Cool for the update, however there WAS a superstition of a "teen" number written in the books you can buy on the 707's.

Not that I'm aware of, but I'll look into it. I thought 717 just never caught on as an inform KC-135 designation. Interesting question. What books have you looked at?

FX1816 · Wed Apr 25, 2012 4:53 pm

Quoting 135mech (Reply 39):
When Boeing bought out MDC in 1995, the MD-95 (DC-9-95) was being introduced at that time

Actually I believe it was 1997. I also believe that the MD-95 was not actually a DC-9-95. That ended with the MD-87 or MD-88.

FX1816

BoeingGuy · Wed Apr 25, 2012 4:59 pm

Quoting FX1816 (Reply 45):
Actually I believe it was 1997. I also believe that the MD-95 was not actually a DC-9-95. That ended with the MD-87 or MD-88.

Yeah, someone posted that recently in a different thread. I think they were type certified as DC-9-82 and DC-9-83, but the MD-87 and MD-88 were type certified as the MD-xx. What I didn't know was that the 720 was type certified as the 720, not 707-020 as I had believed.

Stitch · Wed Apr 25, 2012 5:01 pm

Quoting BoeingGuy (Reply 44):
I thought 717 just never caught on as an inform KC-135 designation.

Boeing Historian Mike Lombardi confirmed in an interview with James Wallace in The Seattle Post-Intelligencer that 717-100 was Boeing's internal designation for the KC-135, hence when the MD-95 was renamed, it became the 717-200 and the proposed stretch was the 717-300.

http://www.seattlepi.com/business/ar...rphan-717-isn-t-out-of-1162508.php

FlyPIJets · Wed Apr 25, 2012 5:22 pm

Quoting 727LOVER (Thread starter):
why didn't Boeing just make a small/mid size two engine, two pilot aircraft for shorter runways in the first place.

Wasn't the proposal for the 727 two pilot at first. Then it was made into a three manned flight deck at the request of UA to avoid a perceived labor dispute?

daviation · Wed Apr 25, 2012 5:30 pm

This is a really interesting discussion. Learn something new every day.

I flew on many 727s - American, Eastern, National.

If I can add anything to this topic, most 757 trainers and pilots did not consider the plane a bigger, newer 727. They took great pains in AWST articles to point out that the 757 was a completely different species, handled differently, had completely different avionics, and basically had no relation to the 727 whatsoever.

As for the 727's noise footprint, we had family that lived in Lawrence, Long Island, right under the JFK approach. OMG! The 727s were loud, but the 707s and DC-8s were beyond belief. The 727 wasn't exactly a "whisper jet," but it was substantially less noisy than the 707/DC-8.

I was even in a landing go-around at LGA because our 727 floated too long over runway 31. And I was a passenger on two different 727 engine-compressor stalls during takeoff. I may be wrong on this, but I heard that the middle-engine had a propensity for cross-wind compressor stalls. That's what our pilot said, anyway.

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