just me Call me old fashioned but I still like the security of having four engines, particularly when I’m half way over the Pacific Ocean and an engine fails. I’m flying SYD - SFO in a couple of weeks and I’m glad it’s in a Qantas 747-438.
The 777 is the twin engine 747 with only difference being the lack of the upper deck cockpit which was really designed to be able to have a nose cargo door for oversized cargo. While the 747 is an Icon of aviation, the 777 does what passenger airlines want with greater efficiency as proven by the lack of passenger orders for the 747-8. The nose cargo door option wasn’t important to airlines whose cargo business can be served under deck or by a freighter version of the 777.
@@ashleymalamute The 777 is design in 10 abreast aircraft not nine,this is requested by Cathay Pacific during the working together program of 777 development.
Yeah, that's the ticket. Imagine a plane that 4 GE90's would be necessary for. A 900+ pax plane that no airport could possibly ever service. lol But hey from what I see on RU-vid Airliners fly on Free Energy no fuel needed anyway.!! 9/11 happened cos someone had a cigarette-lighter in their carry-on (and a hairspay aerosol).
www.airliners.net/forum/viewtopic.php?t=365677 4 GE90, you are looking at an aircraft that similar size to An225 at least, the biggest plane in the world.
@@thecaynuck4694 imagine the prototype trijet just slams into the ground on landing due to Boeing not thinking about switching out the 727 design and going for the larger trijet designs
Thanks - I was wondering where the hell you would find so many different A380s in one place. Even thought it might be an edited picture. Wouldn't want to try to board economy in that terminal though!
dj cats in da house Unfortunately, darn few SPs exist anymore, and the production line has changed too much to try to Bring them back. I guess we’ll never know.
Perhaps the SP would be a good template for a complete double decker as well. Great concept to start from at least, because originally they were used for shorter haul flights where range was not as important, so that minor clash of concept would need some looking into, but I really like the idea.
Miles Hanna Surprisingly, the 747SP is used for what is now considered "ultra long range" routes. So, it should be taking on the A350 and the A380. 2-for-1 deal.
Or could it be viable if they try this: Merge a 777-300ER's wings and engine to a 747's body. Then they use 3 landing wheels by the wing (4-6-4) and try growing the control surfaces a small bit so it fits in airports
there have been 747s with taller fins like the SP (the small one) and the dreamlifter so it could be possible or the extra fins on the nasa 747 that carries the shuttle
I'm sure it could be done but why.. I prefer 4 engines on a bird that big.. The 747-8 is a work of art even though it is 45 years old it has been refined very well and is in my opinion the most beautiful commercial plane ever.
Im with you propeller head- I keep wanting to hear that some airline is ordering 50 747-8is. I was glad to see ups order the freighters, but to me its like an ex champion boxer getting a job mopping the gym. That plane is too beautiful and capable to disappear. The ball point is an old design too...
Well, I saw GE is testing her new GE9X engines using a 747, they said one single engine could generate enough thrust to keep a 747 flying (something essential to get the ETOPS certification for a bi-engine airliner). Honestly, I think the only way to save the "Queen of the Skies" is to turning it into a bi-engine airliner. Otherwise, it would lose ground to more light weight airliners like the B-777X, the B-787 or the A-350. Plus, a more efficient B-747 could KO the A-380 for good and win the battle of the Jumbo airplanes. To be honest, I have a hard time seeing the B-747 slowly dying.
That's what has been said. Technically it's possible. But their 747 was a test bed, that will never fly fully loaded or have an emergency where it would be necessary to fly with a single engine. To perform all adjustments required in a regular 747, will need a new wing, new fuel tanks, new flaps, slats, tail, etc. The wing is one of the most expensive parts of an aircraft to design and produce, so it's not gonna happen (unfortunately).
Ok the 747 your speaking of is owned by GE. Its their private aircraft that is utilised for inflight testing of new engine designs. As someone else said reconfiguring the 747 wing for one engine per-side would require a completely new wing which would require recertification of the entire aircraft. NO, the 747 was originally designed as a military transport aircraft. That's why it had the second story so that it could/can be loaded straight on from the front. Boeing lost out to the Lockheed C5A and as a secondary effort to recoup their investment in the development of the new plane they gave it a name, 747, and added seats. Originally Boeing had the upstairs set up for the flight crews but Juan Tripp of Pan American who had agreed that if Boeing built it, he would buy it said the upstair seats were now first class seats for revenue. The thing is Boeing figured if they could sell a 100 747's then they'd make their money back and perhaps some profit. That was as far as Boeing figured it would go. That was in what 1970-75. The only airliner I know that's been in production longer is the 737 in all its various forms. SO sadly yes production of the 747 will be coming to and end. That will be decided by the customers when their no longer buying any. Everything has a life cycle, planets, countries, people, and airplanes!
The 747 will continue for possibly decades as a cargo hauler. It was designed to be a cargo hauler as well, unlike the A-380 whose production will end soon and has been commercially unsuccessful.
@@solid1378 I don't get why people say the a380 was unsuccessful. Airbus got their money back from the design. It was never an airplane designed to sell by thousands like an A320. The super jumbo market doesn't work like that. And let's not forget that there are a lot of 747 built because the 747 is from the 70's. On the other side the a380 has been in production for little over then 10 years.
@TRAviation There are so many articles that show that Airbus will never recoup its investments in the A380 program. They just have not sold enough of the planes as anticipated. It came too late and was doomed by advances in jet engine technology, end of the HUB System and ETOPS. The 747 design has been around since the 1970s, and while passenger service is ending now, it will continue for decades after as a cargo hauler. If not for Emirates, the A380 program would have shut down much sooner. It is predicted that when Airbus fulfills the most recent Emirates order the A380 program will shut down in favor of the A330 and A350 programs. Unlike the 747, the A380 was never designed to be a cargo hauler, so it will most likely be the final end of the program.
Sadly finacial incentives are more valuralble than looks im afraid, its a shame i only see vigrin atlantic 747 coming into manchester but its rare seeing 4 engines aircraft, fuel prices are so high its making it hard for airlines to consider using them any more D:
Flagstaff Rail Fan 55 Keeping it with 4 engines isn't an option. Too inefficient these days. The options are letting it go extinct or figure out how to make it use just 2 engines
BizzarFish1 It's not only fuel prices. It's also maintenance costs for keeping 4 engines good to go. That makes it cost twice than a one with 2 engines
The need to put these on the B-52H 2 on each wing. Since the pylons are currently 2 nacelles per pylon now it should handle a single 90. That would give the B-52 awesome power, longer range & quicker take offs.
The high altitude performance of a fanjet is not likely to be comparable to the turbojets used on the B-52. If they could afford the loss in altitude the take off and climb performance, not to mention the cruise duration, would be greatly enhanced
In ideal conditions two GE90 engines can easily power a 747. However, when a 747 currently loses an engine, it still produces thrust to offset yawing on that wing. Also, most people assume losing an engine on a twin will reduce its performance by 50%, that's incorrect. The drag now caused by the inoperable engine relates to a more hefty 70% simulated loss. That means that all is well until an engine fails at a critical point in flight, ie: VR @ MTOW. The GE90 powered 747 in that situation would likely be unable to climb or hold wings level and crash. With 4 engines. The likelihood of two engines failing is 200% less than that of a twin which would cause the same scenario outcome and that's why even though Boeing has considered it, would never take it further. Safety.
Good video and idea. I too have thought about this before. I think that there can be a jet bigger than the A380 in tri-jet style, with 3 GE90's. That would be a huge fan to fin in the back, so the intake duct would need to be shaped around the top of the fuselage and the APU relocated entirely.
Had the same thoughts about a twin engine 747. That aircraft is a work of art. You bring up a lot of good points about stress issues. It would be easier to put the "hump" on a 777 probably.
The wing would have to be redesigned and given the cost of retrofitting a new wing as well as new engines, it would probably not be economically feasible. I firmly believe that Boeing saw "the writing on the wall" regarding the future of the 747 and decided that the new 777X would be the best compromise for carriers who wanted to have almost as many seats as in a 747 but in a totally modern plane.
In an engine failure, you now only have 1/2 the thrust instead of 3/4 the thrust the old way, but they're able to handle that on a 777, so I am sure it might be theoretically possible.
There was an early attempt to re-engine the 727 for 2 larger, more efficient turbo-fan engines, redo the tail without the upper intake and eliminate the 3rd engine, but Boeing would not provide the technical info to the company that wanted to do the modification. Boeing wanted to instead sell newer 2 engine 737, 757, 767, etc. A redesigned and more fuel efficient 727 would have been unwanted competition.
How about two bigger inboard "cruise" engines but also retaining two smaller engines on the outboard stations that are only used on take-off, at landing and in case of main engine failure? Once in cruise, they could be shut down and a streamlined cover pulled in front of the intake fans. And with total thrust levels planned such that any combination of three engines or both of the large ones could keep it safely in the air or get it airborne once past v1.
Benny Löfgren it's a nice idea, but would mean the airlines would have to hold two different types of spares for one aircraft type. Aircraft design often centres around common spares so as to save airlines money in storing spare parts.
So you would have two dead weights providing no trust. Also on top of that you would have a technical sequence prone to technical errors and thus complicate take off and landings and increase cost. Rather go with two engine then...
It has never stopped being the queen of the skies. I mean the A-380 is bigger and more modern but came 20 years too late. All hail to the JumboJet B747
I actually asked this on youtube 10 years ago. An aeronautical engineer explained that you would have to re-engineer the lower belly of the plane because of a change in aerodynamics. I believe the angle of attack would be very fragile to maintain, maybe larger rear rudder, because no drag is present on the out board wings. Physics plays a major role in designing an aircraft. Not only parasitic drag and other airflow inducing effects, power thrust, but weight distribution as well. Aircraft MUST burn off fuel prior to landing to prevent airframe fracturing, or worse destruction. Two larger engines will probably weigh more, fuel consumption might be an issue because of the drag of the rest of the plane will make maintaining thrust unorthodox than if it had all 4 engines. Also, politics involved with keeping jobs and fuel consumption. Redesign of the plane to handle the thrust power and weight of the plane carrying two engines will be probably the most important consideration to take when inducing something like this. Also, the cost to re-engineer and re-engine the plane makes it pointless, unless you're Warren Buffett, Bill Gates, Donald Trump or Richard Branson.
Back in the 70's I saw a 747 land and taxi in Honolulu it was transporting externally a spare engine capped front and rear More importantly can we due this to a B-52?
The 777 I don’t think it could be stretched past the -300 line ,it is already a very long plane. The 747 with new designed wing with only 2 large engine built new. Could have a large cost savings, in not having to redesign the main fuselage and tail assembly along with the landing gear ,a/c ,electrical systems, and the many other systems found in the fuselage. The retired 747 (2 engine)after passenger service can be used as cargo aircraft ,where as the A380 would take a major redesign to have front opening nose door added.
It is beautiful!!! The world's greatest plane could've been created but they stuck with 4 engines on the 747-8 even though they overhauled the wing design anyway
It's already been done. Boeing used a 747-100 to test the GE90 when it was in developement. Theres a video in RU-vid but can't seem to find it at the moment.
Call me a wuss but I simply have concerns about extended flights over open ocean with two-engine airliners. You're in very little peril losing 1 out of 4 engines half-way to Sydney but losing 1 out of 2 just past the half-way point increases your chances of having to ditch by a huge factor. I know the probability is extremely low but for such corridors, why tempt fate?
Basically it's not economically viable. For airlines it doesn't make sense to spend a lot of money in maintenance and fuel for more engines when the chances of losing one in two engines are so low. It's like saying I'm never getting out of home again because I can get hit by a lightning. It's a stupid comparison but I hope you understand.
Thanks for the image of the Nimrod 02:32, I live at Kinloss their base in Scotland and miss seeing them doing circuits and hearing the ground runs in the early hours of the morning :) interesting video though.
When the GE90 was going through its testing phase, Boeing mounted GE90's on a 747 and it was able to fly for over 3 Hours on just one engine.(I think this was the ETOPs testing).
I actually asked this a long time ago when there was a video showing a 747 using one large engine and blowing chunks of the runway off. An aeronautical engineer said that you'd have to redesign structural support for the belly of the plane to handle the difference in center of gravity with two larger, and probably heavier, engines. He also mentioned that it's just too costly and a lot of re-engineering is involved. Great idea, but too expensive. They might make enough thrust to use little fuel to keep the plane afloat but you have to worry about structural rigidity like fatigue over time. Aircraft have to go through a procedure where they're put on jacks and I think their frames are balanced in certain areas. I think it's called reframing? They almost gut the entire aircraft and it takes months to do but it's for hours on the air frames.
After talking to the pilot who flew that plane during the tests he said they would work just fine. They had trouble getting to 100% thrust on the test engine with both engines on the other side at full throttle. The "at altitude" performance is far superior vs the older engines. The fuel flow was substantially less. He also mentioned they talked about the retrofit but as mentioned in this video the wing would have to restructured for commercial service. Fine on anything in production but not cost effective for anything already flying
Considering GE and Boeing have already mounted a GE90 to their 747-400 testbed and flown it with the other 3 CF6s shut down, Id say that the fuel flow, ground clearance, and thrust asymmetry is all within the envelope of what the 747 can deliver. Wing loading/airframe stress is really the only question.
to be honest unless we are talking about retrofitting old 747s its not worth it the 777-9 basically meets almost all the 747-8 specs in passenger transport but its much more efficient
The 747 has a character all its own. There’s an excitement to it’s appearance and anticipation of a voyage of adventure to be had. I’ve flown on every jetliner Boeing has ever made but, unfortunately, never on the Queen of the skies.
Pretty good explanation. But there's one thing that you left out, which is how the aircraft would handle in flight. Boeing had looked at going to a 3 engine configuration some time ago, mounting the third in the tail similar to the L-1011 or DC-10/MD11. Their conclusion was that it was both impractical, due to the cost of redesigning the structure of the fuselage and wings, but also because it would have made the aircraft handle much differently. Boeing saw both challenges as impracticable, due to the obvious increase in the cost of the aircraft but also the cost airlines would incur to retrain flight crews. And determined that both together would have off set the savings of reduced maintenance costs and fuel savings. But as you said, its always fun to think of what if's, and look at what could or would happen. But here's another idea to look at. Instead of re-engining the 747, what if we added the extra landing gear to the 777, to increase its max weight rating, making it more attractive as a heavy hauler?
The main problem is engine out performance. You would be severely limited on takeoff weight to ensure that your single engine performance is great enough for a safe departure.
Interesting topic. I'm sure that Boeing considered a two-engine option when they worked on the 747-8, because the ETOPS increases that killed the market for quads occurred in the 90s and so Boeing had a decade to watch the market shrivel up. By the way, I like your channel and subscribed yesterday. I hope you keep making interesting videos and start getting more views and subscribers. Don't be discouraged by the low views on your channel so far!! 👍
Very interesting concept. While I agree with the fellow that stated to leave it be due to the majesty of the aircraft, I can see the idea of lessening the overall weight and fuel usage. I appreciate your breaking it down such that it really wouldn't work.
Take a look at the 747 located at the Top Gear test track. It has 4 egnines but they are placed in pares on the inner pylon on each wing. Outer pylon has some sort of tanks I think
Ah, but what would work would be 3 engines on a 747 - unfortunately, this would be a major undertaking. Two large engines at the inboard stations on the wing, and a third, smaller, engine mounted in the tail 727 or L-1011 style with a novel new feature. That feature would be a retractable inlet so that the engine would be exposed to the air stream on takeoff and during the initial climb out, but then the inlet would either retract into the body, or an aerodynamic wind screen would extend to cover the inlet in flight so it would be as if the engine were not there. This would provide just enough extra thrust so that the two forward engines did not have to be quite so large. As someone pointed out below, however, such a project is likely not to be worth the effort. Maybe Boeing could bring out a 747-9 in this configuration, or a better idea would be a 777-11 with the third engine and make the 777-11 a double decker, full length.
Didn't Boeing consider a tri-jet configuration of the 747 back in the 1970s? Admittedly, a vertical stabilizer with a GE90 at its base would look downright weird.
Yaboinav Aviation I read that they canned that idea, because it would’ve required a complete redesign of the wing. Which also meant that there would be more pilot-retraining necessary. So they went on to develop the 747SP instead!
After all the catastrophes with the DC10, unlikely to try it again. How about hanging the third engine from the belly of the plane? Will need taller landing gear.
You, the author of this bring up a lot of great points why it would not be viable to convert a 747 airframe to 2 engines. On the other hand, it's just laughable with some of the comments being made about two extra smaller engines, etc. I have no engineering background but was a flight instructor for ten years and have read much about aviation technology. I think a lot of these comments are coming from very young and naiive posters. Hey! They have every right to post but I try not to post comments or recommendations where I'm not qualified to do so. My understanding there is a big surge on converting 747-400 And 300 series into cargo aircraft because of the increased capacity demand-which would all but negate the possibility of converting the 747 into a twin jet anyway.
Actually, you wouldn't need to much modification at all. All aircraft are designed today so that future versions can receive very simple, low cost modifications such as new wings or tail, or just stretching the hull. The -8 has a brand new wing and tail compared to the -100. So all you would need to do is redesign the wing, and that would be it, even a new tail isn't necessary as the rudder is used to adjust for that turning moment anyway. It would actually make a lot of since overall, especially since the 777 can't get any larger without adding a second deck.
Jame M you got me wondering if they could do a 777/747 hybrid. 2 ge90 engines one a 747 using the wings (or derived from the wings of) the 777. Probably no.
Well, that's not to say it wouldn't take work. But they use the 747 to test the 777's engines now, and it does this with all 4 of its original engines. So the structure is there. The problem will be the V1 issue someone brought up (but even that is probably less of an issue that we know, it just has to be able to reach 1,500' by climb 2, or about 2,000 beyond the runway) Also, the tail doesn't need to be much bigger if it ever did. With the engines being allowed to sit closer to the frame, that twisting moment from single engine ops is reduced, that's why most twin jet engines are mounted closer than the inboard engines on a quad jet. The problem...cost of certification would be one problem, but the second is if Boeing saw the need for it, which is probably a no they don't. But if they did, it would be a plane that could carry 500 people in all coach config with far lower operating cost than a fully loaded A380 with a range that could equal that of a 777-200LR.
Apart from the engine out considerations, the hydraulic, electric, fuel and pneumatic systems would all have to be redesigned for 2 engines. It’s easier and cheaper to start with a clean slate.
I already had this idea for a private plane. 747 SP with 2 GE-90 engines capable of flying 12,500 miles non stop. The landing gear would need to be taller. A complete redesign would be required. Definitely doable.
Maybe Boeing could eventually make a 747 replacement with everything That a 787 has today but with two engines which i predict will become much more advanced and able to carry more passengers over the decades
4 GE90s are the answer! With such a large engine you only need full thrust of all four on takeoff and Landing but during Cruise only two need to operate Oh, and make it double decker will ya?
Joao Chiari actually the weight would balance out given that the latest generation 747 has lighter wings And fuel consumption won't be massive at all especially when all four Ge90s on a 747 won't always need to run at the same time...
The biggest advantage of the 747 is it’s high ETOPS rating. If it were to transition to 2 engines, the 747 would then have to re-prove itself to re-earn a higher ETOPS rating.
I've thought about this for a while now....i figured building a completely new 747-9 with completely redesigned wings....set up for two GE-90x... wouldn't be as costly as a completely new aircraft....If you've watched Top Gear Uk....you will notice a modified 747...with 2 engines on a single engine pilon..like a B-52...parked on the runway....in the background...cant see that being much different than a single larger GE-90X....other than ground clearance to runway...i could see this keeping the 747 fuel efficient and viable for another 30 years...
They actually kinda considered this with a trijet 747. They ditched the idea for basically the same reasons stated in this video: It would be simpler and cheaper to design and build two aircraft. Are there any examples of modern aircraft that have versions with fundamentally different engine configurations? I know back in the early days of aviation it wasn't uncommon to add a nose engine to boost performance, but I suppose modern airliners are so well integrated that they all bump up against the same sort of issues outlined here.
That begs the question, why didn't they try to design the 747-8 with a 2-engine solution, since fuel efficiency is becoming such a squeeze on all the 4-engine aircraft? They reworked so much of the plane that they should have done it then, if they had any chance to make that work at all.
Don't really mind his accent, at least it isn't one of those annoying robotic voices that are unable to say things properly according to the situation.
I find the outside appearance of the 747 200 the most pleasing, and there might be an advantage as far as weight given just a little sacrifice of capacity. Get the impression they were trying to squeeze too much into it with the following models rather than, heaven forbid, going to a larger-still jet platform.
You'd definitely need to beef up the structure. At my old job, we had a PW4000 in the #2 position on a 747SP. There was more thrust bracing inboard of that engine (installed well before i worked there), but i honestly don't recall there being any extra structure for the weight of the engine. I could be wrong. The PW4000 was definitely close to the ground too.
Making a joke out of my self be like: "Hey what about a 2 engine version of the A340-300?" Minutes later I be like: "Ohh! We have the A330-300" But come to think of it, does the A330 and the A340 have the same wing design? If they does, this concept can be imployed in the B747 but I like B747 on all fours tho.
Since the GE-90 is more efficient, wouldn’t it be a good retrofit to the 747 in all four locations and just run them at reduced output to not over stress the wings?
You forgot to mention a 747-400 has four independent hydraulic systems (& electrical) with each engine driving a hydraulic pump as well as air driven hydraulic pumps (ADP's) in the outer pylons as well as electric hydraulic pumps. Not to mention the way the bleed air & fuel systems are divided up. There's a lot going on under the skin that makes this impractical.
The current 747 tail is probably adequate. Remember that the tail is designed around a failure of an OUTBOARD engine, meaning an enormous thrust imbalance with the remaining outboard engine thrusting away way out on its moment arm, which is probably at least as big an assymetry as single larger inboard engine. But in the end, the 777-300ER can carry 90% of the passengers and more cargo than the 747-400 on half the engines. This aircraft replaced the 747-400 for that reason.