Dear all,

I recently saw the LH Boeing 707 parked at Hamburg airport next to an Airbus 321 and was quite puzzled by the similarity of the two aircraft in regards to size and general design, in spite of the fact that there are several decades (and billions of €/$) of engineering in between these two remarkable airliners. Doing a little research, it appeared that these two birds are also somewhat similar in terms of payload/range; this motivated me to draw the following table summarizing a comparison between them. I took the most advanced versions of both aircraft and collected data from Wikipedia and the forums on this site.

Aircraft: Boeing 707-320B / Airbus 321-200NEO LR
Length: 46.61m / 44.51m
Wingspan: 44,42m / 35,80m
Fus. width: 3,76m / 3,95m
OEW: 67.5t / 50.8t
MTOW 151.5t / 97t
Pax capacity: 189 / 200 (1 class, 34")

Cruise speed: M0,82 / M0,78 (econ)
Range: 5'000nm / 4'000nm (typical)
Fuel cons: 5'450kg/h / 2'200kg/h (mission-dependent, of course)

Flight crew: 3-4 / 2

What to say about these specifications? On one hand, there is spectacular progress made in regards to fuel consumption, which allows the 321 to be built a lot lighter (OEW, MTOW). Also for sure, the pollution levels (noise, emissions) have improved a lot.
On the other hand though, some striking similarities are apparent beyond the physical appearance (an aluminum tube with swept wings and turbofan engines hung under the wing on pods), in spite of the fact that the first flights of these specific aircraft are 56 years apart (1962 and 2018). If we compare this to the progress made in the 56 years before 1962, we are looking at the year 1908 when the distance record stood at just over 1km, covered in 1min28sec by a Voisin biplane...

Have we slowed down our rate of technology progress? Are we nearing the asymptote of the technology, where progress is more and more difficult to achieve? Is this an early sign for an upcoming, disruptive tech progress?

Or is this just what the title said: An unfair comparison.
What are your thoughts?

With best regards,
Hendric

Disclaimers:
- The 707 in LH colors in HAM is actually a -420 version, I know that...
- Of course, the A321 was never designed as a dedicated long-hauler
- Of course, there are more suitable aircraft nowadays for long-haul operations
- Of course, this is not supposed to be an A vs.B bashing thread (just sayin...)

Halving fuel consumption is nothing ;-?
What else has changed:
polution.
crash rate. general savety.
naviation.
control : wire with hyd boost vs. FBW
crew workload ( with the help of modern electronic systems, automation.)
landing/takeoff speeds, runway requirements.
I remember watching the early jet craft taking off at HAM from the "Schrebergärten" and
their totally flat climb gradient, the fat trail of soot and really unbearable noise.

in context: I can't understand the Nimby faction screaming about noise at levels of a soft whisper
in comparison.

Yes. I think progress has slowed. WW2 and the Cold War drove huge advances in technology without considering a need to make profit. Whereas now, we can see that the "new generation" of shorthaul airliner is just a refinement of the previous generation. There's no doubt that we have the technology to create something better than the A320 or 737, but it clearly doesn't make financial sense for a profitable company to invest in expensive technology that it doesn't need to.

However, the A321 is still way more advanced than the 707. To carry 240 passengers at 2500 kg/hr is amazing. And obviously, it's much safer too. Better cockpit, fly by wire, more reliable engines......etc etc.

Incremental refinement, not revolutionary jumps.

By the way, I believe the Lufthansa 707 in HAM is an all business class configuration. I'm told it smells terrible inside due to damp. And I've been told that they move it around the airfield a few times a year to avoid some kind of local tax?????

That's a very interesting exercise.
The 707 and DC8 were called 'giants of the sky' when they were new. Nowadays, the A321, which has more or less the same dimensions, as the OP shows, is considered a relatively small plane.

While there have been important improvements in engine technology (the 707's smoke and noise production would be unacceptable today) and aerodynamics (the A321 carries more or less the same weight with a much smaller wing), the fact that the basic concept is still the same shows that Boeing got it absolutely right first time.

Paint a 60-year old 707 in a modern livery and roll it up to a gate: I expect that only a small minority of the waiting passenger would notice that something is different ("Hey look, it has four engines!"). Try that with a 1958 car...

I don't accept that we have slowed down our rate of progress either. If you look at the industry as a whole, the way it has gone is that form has started following function and an optimum "shape" has been seen to emerge.

Using that basic design of a tube plus low wing and podded engines, then instead of revolutionary designs the next decades were years of refinement. Materials improved, engines went through generations of upgrades and importantly the four cockpit crew of the early 707s crossing the oceans has been replaced by systems that can be operated by just two pilots.

I've said it before but to me the aircraft that really did change aviation was not the 707. It was the 727. Another plane that also served Lufthansa well.

TurboJet707 wrote:

Paint a 60-year old 707 in a modern livery and roll it up to a gate: I expect that only a small minority of the waiting passenger would notice that something is different ("Hey look, it has four engines!"). Try that with a 1958 car...

Depends on where you take your reference car from:
https://en.wikipedia.org/wiki/Volkswagen_Karmann_Ghia
https://en.wikipedia.org/wiki/Citro%C3%ABn_DS

TurboJet707 wrote:

Paint a 60-year old 707 in a modern livery and roll it up to a gate: I expect that only a small minority of the waiting passenger would notice that something is different ("Hey look, it has four engines!").

Fact Check? True



A more apt comparison than the A321 might be a 737 with a big wing and more engines, fewer flight engineers...

This reminds me of a thread many years ago ....

viewtopic.php?f=3&t=288157

This latest thread is far more detailed and just as fun to compare. It shows how very far we have acheived. With passengers' emphasis on low fares, it is not hard to understand why manufacturers have been so focused on efficiency. The airline with the "latest" will always have the edge on cost.

But ... I'll take a 707 (or DC-8) over an A320 series any day!

You need to consider the wing area as well: the 707 has giant wings for it's fuselage, largely because it's just a flying fuel tank.

In 1969 we went to the moon... now we can’t yes things have slowed down..

"In 1969 we went to the moon... now we can’t yes things have slowed down.."

We (the USA) can't even (right now) put a man in orbit either.

COSPN wrote:

In 1969 we went to the moon... now we can’t yes things have slowed down..

SpaceX would like a word...

Starlionblue wrote:

COSPN wrote:

In 1969 we went to the moon... now we can’t yes things have slowed down..

SpaceX would like a word...

words are cheap. hic rhodos, hic salta

i.e. they won't fly manned this year, will they?

Tarantine wrote:

"In 1969 we went to the moon... now we can’t yes things have slowed down.."

We (the USA) can't even (right now) put a man in orbit either.

But we put a car into space.

longhauler wrote:

I'll take a 707 (or DC-8) over an A320 series any day!

I have frequently mentioned that the 321/737 had the bones to grow almost into a 707 replacement. What has happened is the ongoing perfection of the 1950s (even 1940s) designs. Looking at a B47 or B52 is also looking at the nascent shape of a modern airliner. A tube, swept wings, engine pylons, and going a bit over 500mph is what they all are about.

Safety, efficiency, noise, (but not comfort), smaller aircrews, astoundingly less maintenance. These are all purchased at the cost of each hunk of improvement perhaps a magnitude more. I think we have reached the limit as to the improvements available. A and B will update their smaller models with the latest and greatest sometime over the next 20 years. Outside of hybrid power (maybe) I wonder what the next iteration will involve. A better passenger experience in airports may be what it will be about. (hope hope).

Flying AK IIRC out of Long Beach to Seattle, drive up and park next to the gate practically, Champagne (not sure it was from France) for breakfast. Hassle level - about zero.

bohica wrote:

But we put a car into space.

copied from some Canuks )
https://www.youtube.com/watch?v=DWMPe3wF9jQ

TurboJet707 wrote:

Paint a 60-year old 707 in a modern livery and roll it up to a gate: I expect that only a small minority of the waiting passenger would notice that something is different ("Hey look, it has four engines!"). Try that with a 1958 car...

Takeoff noise would show a definite difference between the 707 and A321 (or 737/757).

WIederling wrote:

Starlionblue wrote:

COSPN wrote:

In 1969 we went to the moon... now we can’t yes things have slowed down..

SpaceX would like a word...

words are cheap. hic rhodos, hic salta

i.e. they won't fly manned this year, will they?

Touché. Still, Apollo never landed the booster vertically back at base. That's some cool stuff...

I applaud you hitower3 for your premise.

This is a very interesting exercise. I wonder what the difference in specs would look like if Airbus had tried to optimize the 321 for something closer to the 707 mission profile (that is, without changing the wing). I suppose you'd basically have to take the 321LR, stick even more fuel space in the belly and trade some seating density to get the weight offset to make that useful. Looking at a payload-range chart, I'm not sure it'd even be possible.

Starlionblue wrote:

WIederling wrote:

Starlionblue wrote:

SpaceX would like a word...

words are cheap. hic rhodos, hic salta

i.e. they won't fly manned this year, will they?

Touché. Still, Apollo never landed the booster vertically back at base. That's some cool stuff...

Quite the step. very much a "YES".
( Now they need to change the vehicle to look like a real rocket ship:

)))

Though apollo did VTL, VT'O sequences repeatedly.

IADCA wrote:

I wonder what the difference in specs would look like if Airbus had tried to optimize the 321 for something closer to the 707 mission profile (that is, without changing the wing).

would look like an A319 ( maybe a glider-trailer as tankage extension ?

But the wing would have been changed. much more span.
Compare the proportions : 707-320 (40+m) to 737-100 ( 29m)
i.e. about the A322 that Keesje advertises for.

WIederling wrote:

Halving fuel consumption is nothing ;-?
What else has changed:
(...shortened quote...)
crash rate. general savety.
crew workload ( with the help of modern electronic systems, automation.)

Dear "Wiederling",
This is indeed one major progress I forgot about in my first post.
According to Airbus "Statistical Analysis of Commercial Aviation Accidents 1958-2016", the fatal accident rate decreased from about 8 per million flights in 1962 to less than 0,2 since 2012.
Thanks for this important addition!

Hendric

OldAeroGuy wrote:

TurboJet707 wrote:

Paint a 60-year old 707 in a modern livery and roll it up to a gate: I expect that only a small minority of the waiting passenger would notice that something is different ("Hey look, it has four engines!"). Try that with a 1958 car...

Takeoff noise would show a definite difference between the 707 and A321 (or 737/757).

Most definitely. The noise of a fully laden 707 on takeoff would be frightening to many people nowadays, certainly if it were an old turbojet ('straight-pipe') version during a water-injected takeoff on a hot summer day...



I was only referring to the looks: at the gate few people would notice the difference between a 60-year old 707 and a brand new 737MAX (with which it still shares its nose section) or indeed an A321NEO. I think that says more about the 707 than about the A321.

Want to watch 707s do pattern work, head to Oklahoma City. Always 707s flying around Tinker AFB (E-3s and E-6s). The E-3s are still dirty birds leaving soot streaks in the sky.

TurboJet707 wrote:

OldAeroGuy wrote:

TurboJet707 wrote:

Paint a 60-year old 707 in a modern livery and roll it up to a gate: I expect that only a small minority of the waiting passenger would notice that something is different ("Hey look, it has four engines!"). Try that with a 1958 car...

Takeoff noise would show a definite difference between the 707 and A321 (or 737/757).

Most definitely. The noise of a fully laden 707 on takeoff would be frightening to many people nowadays, certainly if it were an old turbojet ('straight-pipe') version during a water-injected takeoff on a hot summer day...

I was only referring to the looks: at the gate few people would notice the difference between a 60-year old 707 and a brand new 737MAX (with which it still shares its nose section) or indeed an A321NEO. I think that says more about the 707 than about the A321.

I miss those days so much

Even pulling up to the terminal in a car, I miss that turbojet whine, the stronger Jet A smell.. ahhhh.

OldAeroGuy wrote:

TurboJet707 wrote:

Paint a 60-year old 707 in a modern livery and roll it up to a gate: I expect that only a small minority of the waiting passenger would notice that something is different ("Hey look, it has four engines!"). Try that with a 1958 car...

Takeoff noise would show a definite difference between the 707 and A321 (or 737/757).

Oh yeah. JT-3D's! Sound of Music without Julie Andrews!

estorilm wrote:

TurboJet707 wrote:

OldAeroGuy wrote:

Takeoff noise would show a definite difference between the 707 and A321 (or 737/757).

Most definitely. The noise of a fully laden 707 on takeoff would be frightening to many people nowadays, certainly if it were an old turbojet ('straight-pipe') version during a water-injected takeoff on a hot summer day...

I was only referring to the looks: at the gate few people would notice the difference between a 60-year old 707 and a brand new 737MAX (with which it still shares its nose section) or indeed an A321NEO. I think that says more about the 707 than about the A321.

I miss those days so much

Even pulling up to the terminal in a car, I miss that turbojet whine, the stronger Jet A smell.. ahhhh.

Oh yeah, I miss all of that,too. The distinct whine of a JT4. Music to my ears.

What’s interesting to me about these 707 take off shots is not just the amount of smoke they put out but the very low pitch angle


The early days of jet travel did not have the same noise abatement profiles we fly today (not that it would have made much difference)
so after take off it looks like it was just a matter of accelerating, clean up and get to enroute climb speed ASAP unless other considerations were present (like terrain)

Max Q wrote:

What’s interesting to me about these 707 take off shots is not just the amount of smoke they put out but the very low pitch angle


The early days of jet travel did not have the same noise abatement profiles we fly today (not that it would have made much difference)
so after take off it looks like it was just a matter of accelerating, clean up and get to enroute climb speed ASAP unless other considerations were present (like terrain)

With the early turbojets and low-bypass fans with their high exhaust speed, it was similar to accelerating a car in third gear. That's a large part of why they performed better after accelerating, hence the flat climb profiles.

Max Q wrote:

The early days of jet travel did not have the same noise abatement profiles we fly today (not that it would have made much difference)
so after take off it looks like it was just a matter of accelerating, clean up and get to enroute climb speed ASAP unless other considerations were present (like terrain)

Look at thrust to weight. ... and the flat thrust lapse profile over speed on a turbojet or very early turbofan.

Channex757 wrote:

I've said it before but to me the aircraft that really did change aviation was not the 707. It was the 727.

That's an interesting proposition: why the Boeing 727? Would my living in Britain make such a statement sound a little odd to me? Very few 727s were registered here, although we had several a day into Heathrow, mainly Air France and Lufthansa if I recall correctly. I'm sure that there were considerably more 707s than 727s in Heathrow back in the 1960s and 1970s.

But LHR saw the Trident quite regularly during those years.

DrPaul wrote:

Channex757 wrote:

I've said it before but to me the aircraft that really did change aviation was not the 707. It was the 727.

That's an interesting proposition: why the Boeing 727? Would my living in Britain make such a statement sound a little odd to me? Very few 727s were registered here, although we had several a day into Heathrow, mainly Air France and Lufthansa if I recall correctly. I'm sure that there were considerably more 707s than 727s in Heathrow back in the 1960s and 1970s.

Before the 727, jet flight was still a little anchored in the high fare and luxury market that the heavy props operated. The 727, with its JT8D turbofans and beautifully designed wings, helped the shorthaul market evolve as well. It was the most popular airliner of its time.

All of a sudden the hugely popular 727 was out there flying for all kinds of airlines over all sorts of routes because the 3 turbofans made it cheaper to operate. The 737 followed, using many of the same components and engines for smaller markets. Other jets of the same era such as the DC-9 and BAC 1-11 were part of this wave of replacing expensive prop flights with fast and reliable jets.