Sponsor Message:
Aviation Technical / Operations Forum
My Starred Topics | Profile | New Topic | Forum Index | Help | Search 
DC-8 Vs 707 Today  
User currently offlineDLKAPA From , joined Dec 1969, posts, RR:
Posted (8 years 1 month 3 weeks 6 days 11 hours ago) and read 17173 times:

So could this be the reason why there are so many more DC-8's than 707s flying in civil service in the US today?

FAR 91.410 Special MX program requirements.
No person may operate [...] Beyong applicable flight cycle implementation time specified below, or May 25, 2001, whichever occurs later, unless repair assessment guidelines applicable to the fuselage pressure boundary that have been a pproved by the FAA Aircraft Certification Office, or office of the Transport Airplane Directorate, having cognizance over the type certificate for the affected airplane are incorporated within its inspection program:
(3)For all models of the Boeing 707, the flight cycle implementation is 15,000 flights.
(8)For all models of the McDonnel Douglas DC-8, the flight cycle implementation time is 30,000 flights.

So if I'm to understand this correctly, the DC-8 can fly twice as long before needing a re-skinning? Makes sense that cargo operators in the US would prefer it over the 707 if that's the case.

36 replies: All unread, showing first 25:
 
User currently offlineFlyf15 From , joined Dec 1969, posts, RR:
Reply 1, posted (8 years 1 month 3 weeks 6 days 10 hours ago) and read 17210 times:

Douglas built airplanes like tanks that fill niches really well... look at how many DC-10s are out there compared with L1011s... or, heck, DC-3s out there compared with every other airplane of its class/timeframe put together.

And yes, thats my technical reply. Its also why CRJs aren't good at anything. They weren't built by Douglas.

[Edited 2006-10-31 05:59:35]

User currently offlineShowerOfSparks From , joined Dec 1969, posts, RR:
Reply 2, posted (8 years 1 month 3 weeks 6 days 10 hours ago) and read 17200 times:

Quoting DLKAPA (Thread starter):
So could this be the reason why there are so many more DC-8's than 707s flying in civil service in the US today?

Nope, the reason you don't see so many 707's flying these days as has been discussed numerous times before is that the US Air Force bought much of the 707 fleet as it was retired from airline service in order to provide spare parts for the KC-135 fleet. Tail parts were needed and the engines and pylons were used for the upgrade to KC-135E program.


User currently offlineViscount724 From Switzerland, joined Oct 2006, 26021 posts, RR: 22
Reply 3, posted (8 years 1 month 3 weeks 6 days 10 hours ago) and read 17151 times:

Quoting Flyf15 (Reply 1):
Douglas built airplanes like tanks that fill niches really well... look at how many DC-10s are out there compared with L1011s... or, heck, DC-3s out there compared with every other airplane of its class/timeframe put together.

Agree, there's something about all the original Douglas and McDonnell-Douglas types that has generally given them a longer lifespan with fewer major maintenance issues than than comparable Boeing types. I'm not an expert but I've read numerous articles mentioning that the DC-8 has had far fewer problems with corrosion and resulting repairs than the 707. I think the same holds true for other Douglas types like the DC-9 and DC-10..

The other major reason for the DC-8's longevity was its original design which made it easy to stretch the fuselage by 37 feet to create the -61 and -63 models. That made them very attractive as freighters after their passenger days were over, with signficantly larger cargo volume than the largest 707-320 and about the same operating costs.

If NW had inherited a couple of hundred 737-200s from their various predecessors and merger partners instead of the same number of DC-9s, I doubt many of the 737s would still be in service, unlike the 100 plus DC-9s they're still flying reliably and probably will be for another few years, many of which are older than their pilots.

Although I liked the 707 and flew on quite a few, the DC-8 has always been my favorite jet type. A real classic.


User currently offlineLuckyEddie From Zimbabwe, joined Apr 2005, 63 posts, RR: 0
Reply 4, posted (8 years 1 month 3 weeks 6 days 7 hours ago) and read 17058 times:

Reasons:
1) As in post one it is better built and the airframes are lasting longer without major structural maintenance requirements.
2) Douglas designed the aircraft to be stretched. Most importantly the landing gear was long enough to give the tail clearance required. The stretched versions are much better for the parcel carriers than the 707.
3) Probably with the above reasons in mind, 110 DC-8s were re-engined with CFM-56 engines (interestingly this was the first application of this now famous engine). This turned the stretched DC-8s into awesome freighters with excellent performance, fuel consumption and reduced noise.

The 707 had no chance.


Quoting ShowerOfSparks (Reply 2):
Nope, the reason you don't see so many 707's flying these days as has been discussed numerous times before is that the US Air Force bought much of the 707 fleet as it was retired from airline service in order to provide spare parts for the KC-135 fleet. Tail parts were needed and the engines and pylons were used for the upgrade to KC-135E program.

Sorry I can't agree with this. The US airforce would only have bought all these aircraft if they were cheap. If they had been good enough and airlines wanted them, they would have bought them.


User currently offlineSpacepope From Vatican City, joined Dec 1999, 2989 posts, RR: 1
Reply 5, posted (8 years 1 month 3 weeks 6 days 3 hours ago) and read 16918 times:

Quoting LuckyEddie (Reply 4):
Sorry I can't agree with this. The US airforce would only have bought all these aircraft if they were cheap. If they had been good enough and airlines wanted them, they would have bought them.

So the several hundred that the USAF bought and took out of service had nothing to do with the relative lack of 707s in the air today? The USAF bought them because they needed parts for their C-135 fleet, and no other airframes would do. They paid what they needed to pay to get them. It's not like they could have used DC-8s for spare parts....



The last of the famous international playboys
User currently offlineN328KF From United States of America, joined May 2004, 6491 posts, RR: 3
Reply 6, posted (8 years 1 month 3 weeks 6 days ago) and read 16764 times:

Quoting LuckyEddie (Reply 4):
Sorry I can't agree with this. The US airforce would only have bought all these aircraft if they were cheap. If they had been good enough and airlines wanted them, they would have bought them.

Fortunately, the rest of us have facts to keep us straight.

http://www.globalsecurity.org/military/systems/aircraft/kc-135e.htm

USAF acquired about 250 for the KC-135E program. This does not include 17 more that were acquired for the E-8 program.



When they call the roll in the Senate, the Senators do not know whether to answer 'Present' or 'Not guilty.' T.Roosevelt
User currently offlineMiamiair From , joined Dec 1969, posts, RR:
Reply 7, posted (8 years 1 month 3 weeks 6 days ago) and read 16733 times:

Quoting DLKAPA (Thread starter):
So if I'm to understand this correctly, the DC-8 can fly twice as long before needing a re-skinning? Makes sense that cargo operators in the US would prefer it over the 707 if that's the case.

It is not that they need to be re-skinned; a repair assessment has to be made. This is a tedious process for the older ariframes that have numerous repairs on them. The repair has to be documented, shape, size, thickness, material type, repair type (external or flush) etc. This is for airplanes designed under the fail safe concept, airplanes with damage tolerance have another requirement. A damage tolerance assesment may be required for those older repairs.


User currently offlineMDorBust From , joined Dec 1969, posts, RR:
Reply 8, posted (8 years 1 month 3 weeks 6 days ago) and read 16724 times:

Quoting DLKAPA (Thread starter):
So if I'm to understand this correctly, the DC-8 can fly twice as long before needing a re-skinning? Makes sense that cargo operators in the US would prefer it over the 707 if that's the case.

Even if the Airforce hadn't prematurely ended the career of the 707 by parting them out (I still remember seeing rows and rows of them in Tucson), let's do some simple math.

Assuming four hops a day, all year long, that would put the check time for the 707 at just over a decade. At two hops a day, it would be two decades. Suddenly it doesn't seem as important a factor when you consider that many airplanes end up being retired when their Deltas come up.


User currently offlineDeltaGuy From , joined Dec 1969, posts, RR:
Reply 9, posted (8 years 1 month 3 weeks 6 days ago) and read 16703 times:

Quoting Flyf15 (Reply 1):
Its also why CRJs aren't good at anything

Way to insult your own jet  Wink

Quoting LuckyEddie (Reply 4):
Sorry I can't agree with this. The US airforce would only have bought all these aircraft if they were cheap. If they had been good enough and airlines wanted them, they would have bought them.

They were cheap, and it was at a time when the airlines were ditching them and a mass purchase of them was possible. I'm sure if they didn't buy them all up, many of them would have soldiered on in other capacities. 250+ 707's is a pretty large fleet.

DeltaGuy


User currently offlineSLCUT2777 From United States of America, joined Dec 2005, 4138 posts, RR: 9
Reply 10, posted (8 years 1 month 3 weeks 5 days 23 hours ago) and read 16673 times:

Quoting Flyf15 (Reply 1):
Douglas built airplanes like tanks that fill niches really well... look at how many DC-10s are out there compared with L1011s... or, heck, DC-3s out there compared with every other airplane of its class/timeframe put together.

I've often wondered if Douglas would have focused on making an air frame to go head to head with the Boeing 757 that could have been their salvation for a few more years rather than re-shoeing the DC-9 and then just giving the DC-10 such a big make-over (MD-11). The 757 is by and large a twin-jet version of the 707 with a slightly more versatile and yes stronger fuselage of a 707 with newer larger twin engines rather than the quad set. Could Douglas have taken the DC-8 a step further and had loyal air carriers like Delta go for it instead of the 757 by the early 1980s?



DELTA Air Lines; The Only Way To Fly from Salt Lake City; Let the Western Heritage always be with Delta!
User currently offlineAKelley728 From United States of America, joined Dec 1999, 2194 posts, RR: 5
Reply 11, posted (8 years 1 month 3 weeks 5 days 23 hours ago) and read 16644 times:

Quoting LuckyEddie (Reply 4):
Sorry I can't agree with this. The US airforce would only have bought all these aircraft if they were cheap. If they had been good enough and airlines wanted them, they would have bought them.



Quoting N328KF (Reply 6):
USAF acquired about 250 for the KC-135E program. This does not include 17 more that were acquired for the E-8 program.

The pictures speak for themselves:

View Large View Medium
Click here for bigger photo!

Photo © Jim Newton
View Large View Medium
Click here for bigger photo!

Photo © Jim Newton



View Large View Medium
Click here for bigger photo!

Photo © Orlando Sotomayor
View Large View Medium
Click here for bigger photo!

Photo © Andy Martin - AirTeamImages



User currently offlinePanAm747 From United States of America, joined Feb 2004, 4242 posts, RR: 8
Reply 12, posted (8 years 1 month 3 weeks 5 days 23 hours ago) and read 16619 times:

As was stated before, the 707 design was not a flexible one. It could not be stretched without a massive redesign, and the era of a two man cockpit was just coming of age.

In my opinion, the 757 is the logical successor to the 707. Everything you would ever want improved on the original design is basically found in the newer jet. Even the longevity has been extended - some of the oldest 757's are still flying.

An ironic point to me - the 757 is being discovered as the perfect trans-Atlantic vehicle for certain routes, nearly 50 years after its predecessor pioneered routes across the pond.

The DC-8, however, was a design that was MEANT to be stretched and extended and changed. The ultimate "transformer" passenger plane, new wings, stretched fuselages, and new engines, a DC-8-73 bears little resemblance to a DC-8-10 except in name.

Both were/are great airplanes and deserve to be remembered as the great leaps in technology that they were!



Pan Am:The World's Most Experienced Airline - P(oor) S(ailor's) A(irline): San Diego's Hometown Airline-Catch Our Smile!
User currently offlineTomTurner From United States of America, joined Mar 2005, 247 posts, RR: 17
Reply 13, posted (8 years 1 month 3 weeks 5 days 23 hours ago) and read 16601 times:

I am not an expert by any means, but we are really comparing the life of the programs' deriviatives while not counting the USAF/military.

It is accepted that Douglas built very rugged aircraft and the 707 did not allow for all the re-engine options or stretches of the DC-8, but its not as if there are an especially lot (I don't think) original fuselage length, early-"ish" engine DC-8s flying around as compared to 707s really.

Tom


User currently offlineN328KF From United States of America, joined May 2004, 6491 posts, RR: 3
Reply 14, posted (8 years 1 month 3 weeks 5 days 23 hours ago) and read 16591 times:

Quoting TomTurner (Reply 13):
I am not an expert by any means, but we are really comparing the life of the programs' deriviatives while not counting the USAF/military.

The point many of us are trying to make is that the 707s commercial life was cut short when 250+ viable and flying airframes were bought up for scrap. USAF didn't have much choice, as to them, it was cheaper than having many of the parts manufactured anew. That's not to say the airframes didn't have commercial value...



When they call the roll in the Senate, the Senators do not know whether to answer 'Present' or 'Not guilty.' T.Roosevelt
User currently offlineTomTurner From United States of America, joined Mar 2005, 247 posts, RR: 17
Reply 15, posted (8 years 1 month 3 weeks 5 days 23 hours ago) and read 16564 times:

Quoting N328KF (Reply 14):
The point many of us are trying to make is that the 707s commercial life was cut short when 250+ viable and flying airframes were bought up for scrap. USAF didn't have much choice, as to them, it was cheaper than having many of the parts manufactured anew. That's not to say the airframes didn't have commercial value...

Oh, yes, I agree completely...

More responding to the initial suggestion/question that the 707 was not around, while contemporary DC-8s might be, due to durability related issues..  Smile

Tom


User currently offlineAlessandro From , joined Dec 1969, posts, RR:
Reply 16, posted (8 years 1 month 3 weeks 5 days 22 hours ago) and read 16548 times:

So the B720 was it considered for spare parts to the USAF?

User currently offlineN231YE From , joined Dec 1969, posts, RR:
Reply 17, posted (8 years 1 month 3 weeks 5 days 21 hours ago) and read 16479 times:

Quoting PanAm747 (Reply 12):
In my opinion, the 757 is the logical successor to the 707. Everything you would ever want improved on the original design is basically found in the newer jet.

Not to be "nit-pickety," but Boeing designed the 757 as a "modernized" 727. However, the 757 having commonality with the 727, and the 727 having a 60-70% commonality with the 707, I guess you can say that the 757 has roots to the 707.


User currently offlineSLCUT2777 From United States of America, joined Dec 2005, 4138 posts, RR: 9
Reply 18, posted (8 years 1 month 3 weeks 5 days 21 hours ago) and read 16447 times:

Quoting N231YE (Reply 17):
Not to be "nit-pickety," but Boeing designed the 757 as a "modernized" 727. However, the 757 having commonality with the 727, and the 727 having a 60-70% commonality with the 707, I guess you can say that the 757 has roots to the 707.

In the fleet line-up of most carriers you could say the 757 was the logical successor, but as far as "metal" commonality it really was more closely related to the 707. It looks as if Boeing has timed the real replacement to the 757 to coincide when many operators look to start replacing their fleets of 757s in mass.



DELTA Air Lines; The Only Way To Fly from Salt Lake City; Let the Western Heritage always be with Delta!
User currently offlineN707PA From United States of America, joined Apr 2000, 279 posts, RR: 0
Reply 19, posted (8 years 1 month 3 weeks 5 days 20 hours ago) and read 16374 times:

Quoting PanAm747 (Reply 12):
In my opinion, the 757 is the logical successor to the 707. Everything you would ever want improved on the original design is basically found in the newer jet.

Except for range.


User currently offlineSLCUT2777 From United States of America, joined Dec 2005, 4138 posts, RR: 9
Reply 20, posted (8 years 1 month 3 weeks 5 days 19 hours ago) and read 16340 times:

Quoting N707PA (Reply 19):
Except for range.

The logical 175-200 PAX a/c Boeing comes up with to replace the 757 will probably have that greater range that carriers like CO and DL are looking for to better serve these more moderately sized Europe markets from JFK and ATL, but at 787 efficiency.



DELTA Air Lines; The Only Way To Fly from Salt Lake City; Let the Western Heritage always be with Delta!
User currently offlineBeech19 From United States of America, joined Jul 2006, 936 posts, RR: 4
Reply 21, posted (8 years 1 month 3 weeks 5 days 19 hours ago) and read 16282 times:

Quoting Alessandro (Reply 16):
So the B720 was it considered for spare parts to the USAF?

Well... considering the KC-135's(aka 717) were built from 720 airframe. It would have been the logical step except the biggest thing they wanted from the 707 airframes was the motors. That was the biggest jump from a KC-135A to an E. With minor mods to the tail i beleive also.

Its too bad no one ever took a 707 and mounted CFM56's on it (ala KC-135R's).  Smile



KPAE via KBVY
User currently offlineN328KF From United States of America, joined May 2004, 6491 posts, RR: 3
Reply 22, posted (8 years 1 month 3 weeks 5 days 18 hours ago) and read 16258 times:

Quoting Beech19 (Reply 21):
Well... considering the KC-135's(aka 717) were built from 720 airframe. It would have been the logical step except the biggest thing they wanted from the 707 airframes was the motors. That was the biggest jump from a KC-135A to an E. With minor mods to the tail i beleive also.

This is not true.
  • The 367-80 formed the basis for the 707 and C-135
  • The C-135 was almost directly derived from the 367-80, and flew in 1956
  • After having substantially modified the 367-80 plans to form the 707 (6" wider), the 707 flew in 1958
  • The 720 (originally 707-720) was a simple shrink of the 707



When they call the roll in the Senate, the Senators do not know whether to answer 'Present' or 'Not guilty.' T.Roosevelt
User currently offlineBeech19 From United States of America, joined Jul 2006, 936 posts, RR: 4
Reply 23, posted (8 years 1 month 3 weeks 5 days 18 hours ago) and read 16182 times:

Quoting N328KF (Reply 22):
This is not true.

Oops... someone smack me. Holy crap... i had a total mind melt. After all the time i have spent around 135's i can't beleive myself.

I mean't -80... not 720. My mind was... well... nevermind. Thanks for the wakeup call.



KPAE via KBVY
User currently offlinePanAm747 From United States of America, joined Feb 2004, 4242 posts, RR: 8
Reply 24, posted (8 years 1 month 3 weeks 5 days 17 hours ago) and read 16155 times:

Quote:
In my opinion, the 757 is the logical successor to the 707. Everything you would ever want improved on the original design is basically found in the newer jet.

Not to be "nit-pickety," but Boeing designed the 757 as a "modernized" 727. However, the 757 having commonality with the 727, and the 727 having a 60-70% commonality with the 707, I guess you can say that the 757 has roots to the 707.

Actually, I think we're all correct in this matter - the 727 was designed to be a 707 compliment, but today the 757 takes on roles that both planes were designed for, namely trans-Atlantic runs AND domestic routes.

Now if Boeing could have designed a 757LR for CO, it might still be in production!! But then again, that might be the domain of the new 787.



Pan Am:The World's Most Experienced Airline - P(oor) S(ailor's) A(irline): San Diego's Hometown Airline-Catch Our Smile!
25 ShowerOfSparks : Boeing did build one as a 707-700 and tested it but it was deemed a competitor to the 757 so it did not go into regular production. Shame really it l
26 Areopagus : If you subtract those 267 airframes from the 1010 civilian 707s built, that leaves 743 airframes not taken by the military, which is still more than
27 Post contains images Flyf15 :
28 N328KF : To be fair, many of the military 707s have CFM56s. Not to mention all of those KC-135Rs. Well, are E-3s (68), E-6s (quantity?), and C-137s (2) counte
29 Post contains images N231YE : That would have been sweet. Maybe see 747SP ranges . P.S. ...love your username, long live the PA 747-121s!
30 Post contains links Areopagus : Evidently not. Reference.com says, "Production of the passenger 707 ended in 1978. In total, 1,010 707s were built for civil use. The military versio
31 Post contains images Viscount724 : Various DC-8 histories mention that Douglas could have sold more DC-8s and had interested customers, but they didn't want to cannibalize early DC-10
32 411A : Design critiera for both the 707 and the DC8 are... 707, 40,000 airframe hours DC8, 100,000 airframe hours. Early 707's suffered from extensive skin c
33 2H4 : Do you mean you also flew DC-8s? I've been wondering which of the two has a more intuitive, straightforward systems layout. Not that either of them c
34 411A : No, 2H4, I flew only the B707, both short and long body models, straightpipe and fan powered. However, those that I have spoken with who have flown bo
35 Post contains images N231YE : I was going to ask how were the strait-pipes, I always wanted to see them in action and here how they performed, but then you replied; I guess since
36 Mohavewolfpup : are there surviving 707's that are still flown in the US or mothballed for a mueseum? i'm kinda worried that these have been reduced to trash status a
Top Of Page
Forum Index

Reply To This Topic DC-8 Vs 707 Today
Username:
No username? Sign up now!
Password: 


Forgot Password? Be reminded.
Remember me on this computer (uses cookies)
  • Tech/Ops related posts only!
  • Not Tech/Ops related? Use the other forums
  • No adverts of any kind. This includes web pages.
  • No hostile language or criticizing of others.
  • Do not post copyright protected material.
  • Use relevant and describing topics.
  • Check if your post already been discussed.
  • Check your spelling!
  • DETAILED RULES
Add Images Add SmiliesPosting Help

Please check your spelling (press "Check Spelling" above)


Similar topics:More similar topics...
DC-8 Vs B-707: posted Sat Aug 19 2006 06:23:54 by Blackbird
"Airplane!" DC-8 Or 707? posted Sat Mar 2 2002 23:08:16 by 777236ER
Was The DC-8-62/-63 Quieter Than The 707-320B/C? posted Thu Oct 20 2005 00:52:19 by Happy-flier
DC-10-30 Vs DC-10-40 posted Fri Mar 19 2004 03:08:13 by Hawaii50
DC-10 N1 Vs EPR posted Tue Mar 9 2004 02:50:46 by UAL Bagsmasher
A330 Vs. Dc-10-30 Fuelburn posted Thu Oct 16 2003 09:01:28 by Timdegroot
MD-10 Vs DC-10 Vs MD-11 posted Mon Dec 9 2002 06:48:01 by Gigneil
Fuel Eff. 732 Vs DC-9-30 posted Wed Dec 4 2002 17:37:11 by BUFJets
Why DC-8 Chosen Over 707 For Freight? posted Tue Jul 2 2002 21:25:54 by BUFJets
Which Components Are Hydraulic (DC-8/707) posted Thu Feb 28 2002 21:10:31 by Blackbird

Sponsor Message:
Printer friendly format