Boeing 7J7 - The Boeing 737 & 727 Replacement Aircraft That Never Happened
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- čas přidán 30. 10. 2020
- The Boeing 7J7 would be the successor to the Boeing 727 and replace the Boeing 737, changing short-haul flying forever. Today, it may even be the template for Boeing's next aircraft the 797 - Let's explore... the never built Boeing 7J7.
The 80s was an exciting time in aviation. Airbus had entered the scene and rivalry between aerospace builders was entering fever pitch! .On a cool morning in March 1984, Airbus smugly revealed to the world the Boeing 737 killer - the Airbus A320.
Boeing needed something to trump its rival, and the very next year entered the Paris Air Show with an elaborate mock-up of an incredible machine that would be entering the market only seven years later. The Boeing 7J7.
The Boeing 7j7 was designed for a 150 seater market already flying thousands of older Boeing 737s, some of which were approaching twenty years old. It also needed to replace the 7J7 and McDonnell Douglas' DC-9s, focusing on domestic routes and pan European travel around 2,000 nautical miles. Boeing had previously tried to replace the 727 with the Boeing 757, but sales were poor and it turns out, airlines wanted frequency over a bigger narrowbody. Essentially, it was better for customers to have more options for flight times than for the airline to save on airframes.
This is why the plane was powered by an incredibly unique engine - the prop-fan. By having the fans on the outside of the jet engine, Boeing promised jet-like speeds but for a fraction of the fuel cost - a difference of 60% to the nearest another jet!
The engine had propellers with two rows of blades spinning in opposite directions to reduce losses due to “swirl”-energy wasted in imparting spin to the air behind the airplane. Both would be installed on the airplane’s tail, not under the wings, to allow room for the propeller disc and to keep noise out of the cabin.
This plane would also feature fly by wire controls, a glass computerised cockpit like the L-1011, and high strength carbon fiber throughout.
In its first public design iteration, Passengers onboard would have been treated to a twin-aisle cabin of 2-2-2, with no passenger more than one seat from an aisle. The twin-aisle design would cut boarding times by 10 minutes over single aisles and make the aircraft perfect for commuter routes between major cities of a range of 2,700 nautical miles (5,000 km). Boeing would also propose a high-weight version that had extra fuel and could fly 4,250 nautical miles (7,870 km).
To share the financial risks of this $4 billion dollar project, Boeing has enlisted corporate partners from three countries. The Japanese [hence the "J"] had the biggest share of the program - 25 %.
Each Boeing 7j7 would have a list price of around $28 million, which today is $67 million.
SAS wanted a denser version of the plane with a 2-3-2 seating configuration for economy travelers and was contemplating becoming the launch customer. However, other customers were skeptical as the engine technology was unproven at the time.
So why was it never built?
The first problem was that the design was constantly changing.
By June 1st, 1987, Boeing was approaching its deadline to either make the plane or get out.
SAS who wanted to be the launch partner with a commitment to 100 7J7 aircraft
British Airways wanted 35 7J7s to replace their 737-200 aircraft,
and American Airlines wanted 100 units of a stretched version seating up to 170 passengers.
It's this stretched version that really threw a spanner into the works. The engine was already at its limit for this aircraft, and Boeing was concerned that they would paint themselves into a corner if an airline asked for an even bigger version of 200 seats.
Until we hammer it down to one size, the 7J7 won't go, said Dean Thornton, president of Boeing Commercial Airplane Co. In an interview, he said the most confusing part of the decision-making process is trying to pinpoint the airplane's starting size.
And without knowing where to start, Boeing was not going to go. By December 1987, Boeing paused the production of the aircraft.
There are also some other concerns about the aircraft. For one, airlines were skeptical that these planes were as quiet as other jet aircraft, with the fans being exposed out in the open.
The plane only flew at Mach 0.84, which is faster than a turboprop, but slower than most jet aircraft today.
Lastly, the Boeing 7j7 was made for an era of fuel uncertainty. By the late 80s, fuel had dramatically fallen, and the western world had secured a new oil supply.
Today we can very much see that the Boeing 7j7 was a precursor to Boeing next needed aircraft. A twin-asile, 5,000 range, 200 seater aircraft dubbed the Boeing 797. Had the Boeing 7j7 been built back in the 80s, it is likely that today we would see a very different market indeed, although one were perhaps even the Boeing 737 wouldn't be as successful.
My dad worked on that plane, it was SO loud!!! The amount of engineering that went into trying to quiet it down is a story in itself.
The 7J7 would have been a worthy successor to the 727 as it would have replaced Boeing's loudest jet with something even louder.
Can’t match the crackle of three JT8s on takeoff.
Every thing louder than everything else 🤘🏼🤘🏼📢🔊📣
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I don't think they're all that loud. During development, we had an unducted fan engine installed on a 727 and had them do a lot of low level, high speed fly-bys. I would compare the noise level to a P-51. It's actually a pretty sexy sound.
Eastern Airlines called their 727s "Whisperjets."
Who else finds the inefficient planes of the 1970s (like the L1011, DC10, A340 etc) were the most beautiful planes ever
Especially the L1011
@@neogenmatrix6162 yeah
Ugly af
Ugly and twisted on the inside. Remember form follows function in Aerospace .....
A340 is from 1990s
The 7J7 is actually a very interesting concept aircraft to be honest. It's the smallest twin aisle aircraft I know of, and the propfan engines look very futuristic, but they could have been too loud as they were exposed out in the open like you said in the description and video. And I'm looking forward to seeing more from you in the future. :)
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Complete omission of McDonnell Douglas and the MD-80, the model that Boeing was chasing during the mid ‘80s, not the A320 (which program was only launched in 1984 NOT first flight or EIS as implied, with the promo video shown from 1988). The MD-80 UDF also was developed in parallel with the 7J7, making its omission from this video all the more abhorrent.
Do you mean the MD-95?
Especially when you consider the MD-80 UDF spent considerable time in actual flight testing and was further along in development, compared to the 7J7. Certainly a blatant omission/oversight by the author of the video.
@@Ampersandrascott technically it was known as the MD-94X concept, which was tested on an MD-81. en.m.wikipedia.org/wiki/McDonnell_Douglas_MD-94X
@@Ampersandrascott No. MD-80 program tested a UDF version of this propulsion also. McDonnell Douglas may have come to the same conclusion ... capacity to propel the aircraft, noise and fuel consumption may have been factors in the MD-80 not being offered to the airlines with any type of UDF or UHB engine version. Plus this type of propulsion, I don't believe was ever airworthy certified in the US.
Awesome video mate, loved it!!
Go benson
@@FoundAndExplained im a bit disappointed you have a few mistakes in it like a NMA /B797 with a 500 nm range instead of a 5000 nm range
Slight error with the statement on speed: 0.84 Mach is its top speed but the cruise was lower than 0.82 of a normal plane.
Forgive me :)
Some really great clips in this one around 6:50 in! Most won't see it but jump on it if you read this comment :)
I have no idea. can you give me a clue? love your videos
The 787 flies at Mach 0.85 and the 737 flies at Mach 0.79. 0.82 isn’t really that bad even against modern jets
Great 👍 video 📹.
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@@larrygarcia9048 sir, this is a wendy's
Very interesting aircraft. Would have been nice to see how well it would have performed over time.
Such a Wonderful Journey . Thank you for producing and publishing this great video.
Thanks so much for watching!
717- it looks like me!
Boeing- no you’re adopted
717- 🥺
This plane would have been great to fly on, shame it never really happened, but the 737 is still quite nice
McD also was going to make a similar UDF plane based on the DC-9. :)
I remember being on the Oregon coast, sometime in the early 90s and watching a plane fitted with one of those engines taking off from a nearby airport
7:09 Mach 0.84 is not slow. Latest 737 s can manage 0.79 at best.
Yes see the pinned comment. I was incorrect
737s are happy at .785, but can go .80 if the air is smooth and no wave.
yeah those engines were incredibly loud... some antonov has that type too pretty much the only aircraft with such type of engines flying as far as i know.
There is no way that the fans were quieter than a jet engine. The work done on the engine was rolled into new aircraft designs like the Trent 1000
the Russians also had a go. the engine you are thinking of is the Kuznetsov NK-93! It was test fitted to an il-76
@@FoundAndExplained We had un unducted fan on a 727 for our test vehicle. I would compare the noise as being similar to a P-51. Noisy, but not obnoxiously so.
I think you meant 5000 and not 500 nm range for the B797.
Okay why dose this Boeing plane look like a CRJ with propeller engines ?
It doesn’t, it looks like a 727 minus 3rd engine and two propeller engines because that pretty much what it was
CRJ were similar in appearance.
I'll remain skeptical on the noise issue without any audio examples of the type in motion. I'd put as much blame on Boeing's waffling over sizing as the novel engines.
The market for an easy-on/off 200 passenger domestic flight is certainly there, it would have been nice to see these or turbofan equivalents flying around. The T-tail would certainly make them easy to spot among the 2-pod lineup at most airports.
Great to find this in my feed. I was there and remember it well
Glad you enjoyed it. I hope I did the project justice! Let me know if you have any futher details I missed.
B7J7 look very awesome.
Awesome 👌 🆒️ 🙌 video.
I hired into the company on 1985 and worked on 7J7. One item which isn't mentioned is that Boeing had invested heavily in research and development for computer-aided design, specifically Dassault Aviation's CATIA. It wasn't ready for full implementation as of 1987 and it was needed to meet the cost targets for the design and production. So consequently, it was the 777 which benefited from that delay.
Remember too that the industry changed dramatically as a result of deregulation and the adoption of the hub-and-spoke model. Lower oil prices and the surprise success of the 737-300 made the 7J7 an airplane the airlines did not need anymore.
Nice engine and awesome design. Go go go for that
Very interesting, thank you!
Glad you enjoyed it!
New subscriber alert 📢. We are joining your team. Look forward to watching more 😊.
Great!
muy chévere este diseño muy bonito lo fabriquen para viajes largos
Another great video mate, thank you for posting!
The 7j would be a great idea....... in principle but would it really give that much fuel economy? I'm not so sure.
Also, I'm not convinced that putting the props at the rear will stop the noise from entering the cabin..... propeller engines are noisy...... and would the placement of the engines back there work, anyway??
Basically, it's a no go!!
Fun thing is that the propfan engine seems to maybe be making a return as CFM (GE + Saffran) are working on a new modern propfan engine. Perhaps it will prove quieter and reliable enough to be considered as a replacement for the traditional turbofans?
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I'm proud that im ur 12,300 something
Thanks so much for subscribing! Everyone one of you is amazing :)
500 NM range for the 797? Did I hear that correctly? Just subscribed, btw, love your channel.
Love the audible add
I don’t control what ads you see
The 72’ was my favorite bird to fly as far as airliners are concerned. The 73’-800NG’s engineers crammed us further towards the pointy end of the beast. OAK/HNL; after 2hr+30 minutes over the pacific, We were ready to get out. After 4hours, we we’re ready to kill. We could not stretch out up front unless you were the size of a Mercury astronaut.
Those engines were really cool but extremely loud and sounded like chainsaws
The energy has to be displaced somehow and if not swirl it would be noise
@@FoundAndExplained I think it maybe could have been reduced if they shrouded the coaxial contra- rotating blades in a nacelle
@@L33tSkE3t I suppose modern high-bypass turbofans are basically that. The fans are ducted but they're much wider than in older jets.
@@MattMcIrvin Yeah, I guess that would be considered the same principle.
They could learn from the ATRs or the Q400 on how to make them more silent.
Make a video about the McDonnell Douglas MD-94x
The company deserves a lot of videos. I also want to do one on the MD-11
@@FoundAndExplained the MD-11 made an appearance in this video, gorgeous! The Md-80 also had a jet prop prototype that didn't sell and was cancelled. It was advertised as a 30% fuel saver.
What? This is quality content, you deserve 1000 times more subscribers but for now you have one more (me)
Dude thanks so much! We shall see what happens :)
Nice plane!!
Interesting. Never knew about that
For the 2-3-2 seat configuration: What if they turned the outside rows slightly inwards, giving the aisle more room.
If you turn a square slightly sideways it becomes wider by dimension
would have been a very cool machine... should have built it, but i would think that the cost of carbon fibre at the time (USD40/lb before forming) may have been a bit of an issue... but could have been an interesting alternative to the 737-max series... even with conventional jet turbines in place of the jet props, it could have been a game-changer and more future-proof...
Eu abencoo este projeto
Needless to state that this airplane would have been an addition to a long list of daughters to the Sud Aviation Caravelle which was a fantastic airplane which was the second jet liner to enter service in the fifties.
3:08 Mounting engines on the fuselage usually leads to more engine noise in the cabin than if they were under the wings
the engine installed at aft has a character of gravity shift ehen climbing.Unducted engine is evenly balanced when attached to wings.Dynamics must be invedtigated to ensure nice take off performance.
Another concern with unducted fans is the issue of a blade separation. Being unducted, means that should a blade break off, it could punture the fuselage. There are several drawbacks with this engine type and that's why there are still no unducted fan airliners around.
.... interesting thought. But, modern carbon fiber blades are virtually indestructible. If that technology was in existence then, your example would have been a non-issue. Also, shielding can be made to cover that area of the fuselage to prevent a puncture, even with the technology of the time.
man, this thing would be a worldbeater for today. Everyone is flying 737's now @ like 180 pax.
L-1011 glass cockpit? Are you sure about that?
8:16 .....500 NM range?
The ones I flew did not have glass cockpits. They were the older 'steam gauge' style.
Came here to say this also.
I think you may be incorrect about the L-1011 having a glass cockpit. That product design didn't show up until the advent of liquid crystal screens, long after the L-1011 was discontinued. MD-11 and 737 next generation (if i'm not mistaken) were some of the first commercial glass cockpits. Military aircraft would have had them first.
looks good to me
MCDONNELL DOUGLAS also toyed with the idea of putting this very same engine on the DC9 variants, but the engine never proved to be viable
I remember the test flights from the Long Beach California Facility... that engine was loud and a very odd sound at that!
nothing in it's class will ever rival the 727 it was the first aircraft i ever flew in, not just that it's looks the comfort, just an aircraft in it's own class
Had the 7J7 actually went into service, it's likely it could have severely cut into A320 sales. And improvements in blade design would have made it probably as quiet as the A320neo now but with likely even lower fuel butn.
Yup, not to mention they would have probably skipped this entire 737-MAX boondoggle. Now, they're still stuck with loads of 737, which sucks. The A320neo is way better than any 737 models, IMO.
Woww..
1. "Short 'bros' is really Short Brother (& Harland) 2. You mention that MACH .84 was slower than the norm whereas the B737-800 has a Max V NO of 0.81-0.82. otherwise, thanks for the video.
Would have been cool. Similar cabin width as a B767.. at 188 inches this would have been an impressive sight at airports especially for short haul hubs.. Would have improved short haul travel for all.
Nothing can ever replaced the Boeing 727. It was a rather unique configuration that is no longer being made. A criminal escaped with lots of money out of the back of a Boeing 727. It is unknown if the criminal escaped.
They were pretty good to fly too!
D.B. Cooper? Growing up a child passenger on the last 727 models old airframes at the time I'm sure.. I was more frequently aboard 737-200 models. I've searched a few tail numbers and quite often kids like me were invited into the cockpit to meet the pilots before the flight. Pretty standard for the operation at the time. The shamu painted livery scheme has been long retired and only 3 planes had it but my every flight was a window seat above the wing.
@Indrid Cold....The word “unique” stands alone. Saying “rather” unique is like saying “rather wet” water. Unique means only one, there are not “degrees” of “uniqueness”......
Wouldn’t putting the engines on the wings reduce noise more than putting them on the fuselage? Usually wing mounted engines are quieter because they’re further from the cabin.
yes but they wanted a cheap switch to the 727, so no engines under the wings (needed to be able to land low to the ground)
This genuinely makes me wonder how the heck CFM is going to make their RISE engines quiet.
The prop fan also seems like it would have been very noisy anyway. Single rotor turboprops are already very loud so having contra rotating fans would only make the noise worse
Imagine a twin Boeing 727 with a DC-9 tail ❤❤❤❤
then it's just a dc 9-
0:15 what happend to the 737s front landing gear
Too bad it was too noisy. 60% fuel savings is significant. Also, it's a beautiful airplane compared to what we have today IMO. Would've loved to seen it at airports.
I always wondered what happened to that.....
This plane could ONLY do mach .84? That's pretty good actually. The A320 can only do mach .82.
Yes that’s an error. So It can match the Mach of a jet
Short hauler limiter challenge engine replacement untested w/ lack of market interest, conundrum.
Thank you..would have been a n interesting plane if it existed today if it's fuel consumption was really 60% lesser than the jet
I always wondered why they didn't re-engine the base line 727 airframe. No you couldn't put a high bypass turbofan in the center engine bay. But the 2 replacement, outer pylon turbofans could have provided as much or more thrust. Than the original engines with a far lower fuel cost. Propfans are an interesting proposition. Such a design should be marketed to the US Navy. Somthing like a P-8, only purpose built; with a mad boom. In this way commercial sales, including freight options. Could be a profitable way; to promote the "in-land port" concept. Long range, more "on station" time. Jet engine like speeds. Such an aircraft, or a larger variant could replace. Ageing 707 based airframes in service. Just a thought.😎
They did, and christened it the Super -27. It was a retrofit option only as airframe production stopped in 1984. Engines 1 & 3 were upgraded to the larger diameter JT8D-217’s which greatly boosted power. And the retrofit could be used on either the -100 or -200 airframe. Alas very few of the Super -27 conversions were sold, but you can find plenty of YT videos featuring them - the takeoff performance is impressive.
Thank you for your information. Production ended.
The 7j7 could be develop as a electric prop like this. instead of using jet turbine to power the prop, it can be electric.
4:07 Actually Short Brothers are based in Ireland.
Miami vice was a hit show
Safran is researching on the UDF Mk2 and their project is called the open rotor project
it bares resemblance to the GE36 design
given that the who world is pushing for lower carbon emissions.
Maybe the UDF design might see a return since flying faster = poor fuel efficiency
Advanced computer aided design and wind tunnel testing could help design better fan blades that could cut aero drag and help reduce noise pollution that plagued the GE34.
maybe there is a possibility that the UDF could be electric powered or a hybrid system to further cut emissions
the 7j7 was def far to ambitious in the 90s when materials like carbon fiber composites was really expensive to make and the idea of a full glass cockpit was not widely adopted by airlines since the MD/DC/B727 era of planes still have the traditional steam gauges and there is an flight engineer behind the flying pilots.
But now Boeing who designed the 7j7 is now trying to fix their deadly MCAS system in the 737 Max planes but also the Covid-19 virus has practically stopped all air travel indefinitely.
How fast would an experimental aircraft
with a 1500 HP 2 JZ and UDF props get ?
LayMan observation. The exposed props could be risk for bird strikes; maybe.... any comments?
Fanjets are just as vulnerable. The fan cowls and ducts offer very little protection. Their purpose is performance, not protection, so they are designed to channel air.
This vidio launching aircraft now?
With those engines, the first thing that comes to mind is the "Bear" bomber. Man, those fuckers are loud!
Missed the big decision point. FOD damage cost to tail mounted engines and it's maintainability of the expensive carbon fan blades.
Boeing made a mistake discontinuing the 757.
You may be right! I flew on a brand new 757 from Denver to John Wayne in Orange County California.... a very smooth and quiet aircraft.
Ok they basically did with their jets, but they ducted it... turbofans...
The tech would go onto the next series of jet engines
Yea...
Yes, modern turbofans have a much higher bypass ratio than the early ones--most of the thrust is coming from the fan, though it's in a duct. There still seems to be some interest in unducted fans because they would be more fuel-efficient even than modern turbofans, but noise is still a problem.
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Im gonna guess that you can count the number of aircraft who have used the propfan engine on one hand
Isnt it just a precursor to the vastly superior option of the turbo fan jet engine
They can still launch B7J7 as Boeing 727 Twin with/without propfan or TurboFan and B7M7 TurboFan
Why is the program not revived? Fuel consumption is their biggest experience.
As NOISE GOES the MU2, ON THE GROUND, was noisy, and so is the PIAGIO AVANTI II, , even in the air, I can tell what aircraft it is HOWEVER INSIDE ONE due to engine placement they are BEHIND THE CABIN, and NOT NOISY AT ALL, 🇺🇸🇺🇸🇺🇸🇺🇸
Somebody build this in SimplePlanes!
Whats the intro song
I’ll find it for you
@@FoundAndExplained ok thx
The real truth is that it is very hard to get the powerplant to work. I talked with the designers during the 80s and they were very frustrated.
Would’ve been cheaper to build this vs the POS MAX!!!!
Talk about short-sightedness.
Aircrafts like this will soon be hot topic again, when plane developers are trying to think how to make the planes consume less fuel and be more eco-friendly.
The main complain about this new type of engine was its ridiculous loud noise. So all other nitty gritty factors were overshadowed by this. And the narrator dont mentioned this main factor.
I actually mentioned the noise in the video
@@FoundAndExplained ....too bad you didn't have a recorded example of the type of sound this engine makes.... It truly is weird ....and loud !!!
Where does some of your info come from? Mach 0.84 is not slower than most other commercial aircraft... it’s faster than most commercial aircraft.
Very few jets go Mach 0.84!
Yes my mistake I’ll correct that
0:22
Probability zero - the things were WAY too loud and no way to quiet them down enough to meet current noise limits - or even CLOSE.
Mach .84 slower than the jets today??? That's actually faster than most airliners flying out there.
My bad!
@@FoundAndExplained anyway, great video my friend!
. . . almost pulled the tree-guh
make more military videos
8:16 500 NM???
Design different though .. and engine be could have been used for a smaller aircraft
I do remember the engine on an aircraft , but never 2 engines, only one to compare to the other engine of the time, then it just DISSAPEARED ! 🇺🇸🇺🇸🇺🇸🇺🇸
We had one mounted on a 727. Testing showed negative consequences to blade loss, so we decided it was not a viable product to market. I don't know what happened to the engine. I'm sure it's sitting around somewhere.
@@Ampersandrascott My bet is the engine design never made it on any production aircraft. I've not ever seen an aircraft with this type of propulsion since the testing on a 727 and MD-80 ...
Yup - I know.
7j7 could be the 797 or renamed like other aircrafts .
I'm not an engineer - but wouldn't there be more opportunity for failure on the external portion of the engine? More exposed moving parts - more opportunity for failure? That plus the fact this aircraft would be slower. Maybe it's a solution for underserved markets or an opportunity for more economical runs for the 'cheap' passengers who are more interested in saving $$ than saving time.