in a manner similar to my previous video on the death of the tri-jet airliner design in commercial aviation we now look to a similar fall from grace with quad jets once the mainstay of both international and domestic travel for among the world's most famous airlines but today are being slowly relegated into the pages of history as the drive for incredible capacity and range is matched by the increased efficiency of equivalent twin jets leaving the last few mainstream designs on a gradual slide into extinction unlike tri-jets which only came into being during the 1960s the very first four-engine jet airliner came in the form of the de havilland comet of 1949 but even before the advent of jet-powered flight four-engined aircraft had held a strong position in the aviation world primarily for the purposes of redundancy and additional power for carrying increased payloads the very first aircraft to be fitted with a four-engine configuration being the sikorsky oroski vitias of 1913 an experimental tractor biplane used to test the abilities of aircraft in carrying heavier loads in the years following world war one four engine airliners became almost solely the domain of flying boats such as the american boeing 314 clipper and the shorts s25 sunderland this being a deliberate choice for the purposes of redundancy as flying boats were required to travel for far longer distances away from areas where in the event of an emergency they could be quickly rescued specifically the open ocean while land-based airliners which generally traveled over shorter distances and had a wider variety of airfields to access made do with two engines as per the boeing 247 and the douglas dc-3 and three engines in the case of the ford tri-motor although some land-based four-engine airliners did make it into the mainstream during the interwar period including the fokker wolf fw 200 condor of 1937 which saw use with various airlines including deutsche lufthansa ddl of denmark and syndicato condor of brazil after the end of world war ii in 1945 advancements in aviation technology together with a variety of large bomber designs which no longer served a purpose meant quad-engined airliners became essentially the norm for commercial operations with the latter half of the decade comprising all manner of four prop models including the stylish lockheed constellation the douglas dc4 and dc6 the avro tudor the boeing 377 stratocruiser and many more improved engine design cabin pressurization advanced avionics and other major steps forward in the field of aircraft reliability and performance rapidly seeing air travel come to dominate both long and short distance journeys however world war ii also brought forward another major aspect of aviation's future jet propulsion with early jet powered fighter jets such as the messerschmitt me 262 and the gloucester meteor illustrating speed and smoothness of flight which far exceeded that of piston-powered equivalents and thus the direction was clearly set for modern civil aircraft both large and small to accommodate jet engines this mindset having existed even before the war's conclusion as great britain under the brabusing committee had considered a range of commercial airliners that would be released following hitler's defeat one of which was a long-range jet aircraft the pioneering design known as the de havilland comet made its first flight on july 27 1949 and was fitted with four halford h2 ghost 50 turbojets producing 5000 pounds thrust each whisking the airliner to a top speed of 460 miles an hour and a service ceiling of 42 000 feet although britain's aspirations weren't unique as only 13 days later avro canada launched their own pioneering jet airliner design in the form of the c102 jetliner a proposed regional airliner fitted with four rolls royce doe and 517 turbo jet engines producing 3 600 pounds thrust each and pushing the aircraft to a top speed of 420 miles an hour and a service ceiling of 40 000 feet the common factor between these two aircraft was the fitting of four engines as due to early turbojet technology having not been fully proven redundancy was at the forefront of the design philosophy while at the same time making up for shortfalls in power and performance as against modern equivalents these engines would have been down on power and thereby struggle to achieve the range and speed desired for these models to be viable replacements for propeller driven aircraft the only twin jet of this period outside of military applications being the sudavya shonkavel of 1955 a french regional airliner which had not the range of the comet but was a fully reliable and sturdy machine becoming a huge sales success with carriers across the globe the advent of the comet upon its entry into regular service in 1952 was met with both praise and skepticism as while the airliner presented speed and comfort which far exceeded the likes of the constellation and the douglas dc-6 there was a certain degree of doubt as to how proven the technology was although regardless american designers including boeing and douglas had both been considering potential passenger models in addition to the slew of jet-powered bombers and fighters they had been creating to supply nato boeing's first jet model the b-47 stratojet making its maiden flight in 1947 and was a long-range six-engined turbojet-powered strategic bomber despite boeing having struggled to sell commercial airliners during the post-war period with douglas having largely dominated the scene for civil aviation throughout the 1940s and into the 1950s it was through a contract by the u.s air force for the development of an aerial refueller later coming in the form of the kc-135 stratotanker that the company opted to find a passenger application for this upcoming design and following the successful testing of a prototype from july 1954 known as the boeing 367-80 the eventual 707 long-range narrow body airliner was launched in december 1957 and entered commercial service in october 1958. this aircraft being fitted with four pratt whitney jt3c turbo jet engines which propelled the airliner to a top speed of 556 miles an hour and a range of 4100 miles the boeing 707 soon became the exclusive long-range jet airliner available at the time the comet having been grounded in 1954 after a series of metal fatigue related crashes and the avro canada jetliner project having been axed during the same year in order to allow for the provision of fighters to aid in the korean war the boeing 707's extremely versatile and flexible fuselage combined with a timeless style and exceptional performance making it one of the most successful airliner models ever to be constructed while the later douglas dc-8 a quad engine competitor did present a viable alternative although delays in its launch due to pervasive drag issues which even saw a number of examples in service withdrawn and retrofitted with a new wing design meaning it never garnered the same commercial praise as boeing's star airliner by the middle of the decade long-range aviation was dominated by quad jet airliners another motivation as to the lack of long-range twin jets on the market being the so-called 60-minute rule of 1953 or u.s federal aviation regulation 121.161
which had been introduced during the time of piston-powered airliners and was done to bar twin-engine propeller airplanes such as the douglas dc-3 from flying extended routes across areas which were beyond 60 minutes flying distance from a safe airport in the event of an emergency this rule specifically being developed due to the rapid increase of trans-oceanic flights during the post-war period the 60-minute rule remained steadfast throughout the 1950s and into the 1960s and 70s and thus quad jets reigned supreme on the long-haul market for decades without any viable competitors with nearly every nation sporting a highly developed aircraft manufacturing industry creating their own version of the four-engine jet airliner concept the usa seeing a third narrow body model be released during may 1960 in the form of the convair 880 which intended to put speed over capacity so as to provide the fastest coast to coast service within the continental usa but due to its massive fuel consumption and smaller than average tanks was not able to complete the run at full speed without requiring a refueling stop meaning it presented to potential customers a model that had a shorter range and smaller passenger capacity to the more appealing boeing 707 and douglas dc-8 attempts to rectify the airliner's faults with the later convair 990 coronado again failing to fully iron out the problems and resulted in the model becoming an obscure footnote in aviation history outside the usa the british in an attempt to regain the ground lost by the comet disasters of the previous decade released the vickers vc10 a highly advanced quadjet which positioned its four rolls-royce conway engines at the rear of the fuselage while its incredibly smooth profile and t-tail configuration allowed for superb performance that in many aspects outshined the boeing 707 even holding the record for fastest subsonic transatlantic crossing by a commercial airliner although this model was again dragged down in terms of sales its fatal flaw being the aircraft's stringently optimized design which was meant to operate from the hot and high airfields of boac's empire routes to africa and southeast asia the vc10 being not only far more expensive to operate but also incredibly complex to maintain the prospects of which caused boac to outright refuse to take on the model until strong-armed by the british government the resultant airline are selling a trickle of units which barely saw service with carriers outside the united kingdom the soviet union meanwhile came last to the table of quadjets during the early period of long-range jet airliners original proposals being to create a four-engine variant of their pioneering chipotle tu-104 which itself was the second commercial airliner to enter service in 1956 after the comet the eventual tu-110 proposal of 1957 which saw three test units built eventually being dropped due to a lack of orders from soviet flag carrier aeroflot while in 1963 ilyushin released the first successful quadjet design for russia in the form of the il-62 an airliner which has often been described as a facsimile of the vc-10 through its use of four rear mounted engines but would see widespread success across the communist states of the soviet union and be the standard for long-range airliners within the eastern bloc for the next three decades the quad jet would remain on top of the long-range airliner market even with the advent of widebody trijets during the early 1970s in the form of the douglas dc-10 and the lockheed l-1011 tristar aircraft which despite offering high levels of capacity extended range and competitive fuel efficiency weren't able to overcome the cultural phenomenon that was the four engine boeing 747 of 1969. this model which emerged from a failed contract to supply the us air force with a wide-bodied strategic transport aircraft truly being the point where commercial air travel was opened up to the mass market it's up to 400 seat capacity placing it immediately into the ranks of airlines across the globe and making it the very pinnacle of civil aviation technology and design to that point the main catalyst that allowed an aircraft such as the boeing 747 to exist was the introduction of the high bypass turbofan engine which was capable of delivering double the power of the earlier turbojet engine while consuming one-third less fuel although the introduction of the high bypass turbofan was one which also gave rise to the quad jet's first viable competitor the airbus a300 the product of an international european conglomerate and presented fuel efficiency that vastly undercut the tri-jet and quadjet competition a highly important factor following the 1973 oil crisis during which fuel prices spiked and a majority of even the world's strongest and largest airlines including the venerable pan am struggled to maintain profits as they had focused their entire business strategies around fleets of boeing 747s on an expansive long distance network subject to low fuel prices remaining the norm the airbus a300 therefore was seen with great interest by carriers across the globe and while initially hamstrung for american operations by the ever-present 60-minute rule an obstacle which nearly saw the entire a300 project scrapped as early as 1976 it was the last minute acquisition of several members by korean air to work long-distance high-capacity routes across eastern asia that truly cemented the a300s place as the world's first viable long-haul wide-body twin-jet airliner with lobbying by several u.s airlines including eastern airlines and delta airlines who intended to purchase the airbus eventually seeing the 60-minute rule lifted and replaced with the extended range twin-engine operations performance standards or e-tops in 1980 allowing for the first time long-haul flights to be conducted on transoceanic routes by aircraft with two engines since the early 1950s in the meantime as the world's major aircraft builders began to develop twin jet wide body models such as the boeing 767 and mcdonnell douglas's proposed twin-engine dc-10 variant quadjets appeared to have stalled in their propagation due to the influence of the 1973 oil crisis the boeing 747 remaining a strong seller but only in its largest guises the 747 100 and the 747 200 as these could cover their cost per passenger mile figure through their incredible capacity while an attempt to create a highly specific ultra long range variant dubbed the 747 sp or special performance which sacrificed seating in order to extend its flying distance for pan am's proposed network of extra long-haul services from new york to destinations such as tokyo and tehran failed to break even in the midst of sparring fuel prices aside from the boeing 747 the only other brand new quad jet for the period was the illusion il-86 a four-engined widebody airliner which had been in development since the mid-1960s under the aerobus scheme and was to be the crowning achievement of soviet commercial airliner technology at the 1980 moscow summer olympics only for government bureaucracy a lack of suitable building materials and assembly space and a design which failed to meet the standards and visuals by its creators to leave this heavily delayed machine as a commercial failure with individual units being built on a sporadic basis throughout the decade and sold only to carriers within the soviet sphere of influence this wasn't to say that quadjets were now restricted to just wide bodies though the aerospacial bac concord which utilized four rolls-royce snemker olympus 593 turbo jet engines being the world's only successful supersonic transport and would ply its trade on faster than sound runs between europe and the eastern seaboard of the united states for nearly 30 years although the aircraft's career was but a fraction of the goals originally intended for the model as during its early development dozens of carriers from across the globe hoped to introduce concord models so as to create a vast network of supersonic international routes only for concerns regarding sonic booms the 1973 crash of the soviet union's own supersonic airliner the chupolev tu-144 and the spiking fuel cost of the oil crisis leading to this machine becoming an exclusive but niche product for the two state carriers of the nations which were instrumental in its conception perhaps the most obscure application of four engines on a commercial airliner is with the british aerospace bae-146 a regional airliner which intended to utilize short takeoff and landing capabilities so as to access smaller regional airports and inner-city airfields although in order to be capable of departing from shorter runways while at the same time abiding by stringent noise abatement restrictions for urban areas the use of larger turbofan engines was out of the question and thus the 146 was instead fitted with 4 lycoming alf 502r5 power units from the challenger 600 business jet making the airliner one of the quietest jet-powered models ever put into service a fact exploited by british aerospace who affectionately christened it the whisper jet come the beginning of the 1980s the twin jet revolution was starting to hold sway with the boeing 757 narrow body and boeing 767 wide body airliners entering service during the first half of the decade allowing for many mainline carriers to replace their aging quad jets on mass such as the boeing 707 and douglas dc-8 while at the top of the market the 747 remained the undisputed champion for high-capacity long-haul operations its position strengthened further by the axing of the tristar and dc10 trijet after years of stagnating sales figures as well as the subsequent failure of the mcdonald douglas md-11 to truly make waves in the marketplace during 1990 and the launch of an incredibly advanced variation of the 747 family dubbed the 747-400 originally conceived as a range and technology upgrade for the preceding boeing 747-300 as per its announcement back in 1984 as the advanced series 300. launched in 1989 the 747 400 was a whole scale upgrade from the previous 747 models retaining the same airframe but including the stretched upper deck from the 747 300 the inclusion of six foot winglets for better fuel consumption a choice of improved turbofan engines including the pratt whitney pw 4000 general electric cf6 and rolls-royce rb-211 and most importantly the inclusion of an exceptionally advanced two-crew glass cockpit which eliminated the flight engineers position by way of large lcd screens that replace the traditional style of analog dials and gauges making the airliner far easier to operate than earlier models the launch of the 747 400 was again a watershed moment for the world's aircraft manufacturers with mcdonnell douglas proposing in 1991 the md-12 a four-engined fully double-deck airliner which would be similar in size to the 747 but have a capacity of 515 passengers when compared to the 416 passengers of the 747-400 the first flight of the md-12 expected to take place in late 1995 with deliveries commencing from 1997. although despite an aggressive marketing campaign by mcdonnell douglas no orders were forthcoming and in the face of the project's collapsing sales the project was scrapped the proposed year of first deliveries for the md12 being the one in which boeing would acquire the firm in a 13 billion stock swap bringing an end to one of aviation's most famous aircraft builders next to step up against the boeing 747-400 was airbus who developed in parallel to their twin-engined airbus a330 wide body concept a four engine model which would have a greater range and capacity than the twin jet the resultant airbus a340 being released in 1991 and entering service in 1993 though the reality is that the a340 was a model that didn't have the capacity of the latest 747 model to justify the increased cost per passenger mile figure presented by the addition of two extra engines and would not only fall victim to the twin jets of boeing but also its own stablemate the a330 a340 sales averaging at 19 units per year while equivalent 747 400 sales averaged at 34 units per year despite the failure of the md-12 and the less than stellar commercial performance of the a340 the 1990s still saw much use for quad jets across the globe primarily the 747 in both its latest 747 400 guys but also classic 747 100 200 and 300 models from the 1970s boeing 707s and douglas dc-8 having been relegated primarily to freight rolls while other examples such as russia's improved quad jet design for the il-86 dub the il-96 saw extensive use across its home country and nations formerly aligned with the soviet union such as cuba the older convair 880 and 990 as well as the vicar's vc-10 falling victim to the rapid expansion of twin jets during the early 1980s and were either disposed of sent to museums or placed into the employee of military factions as test beds or air-to-air refueling tankers the promise of quadjets making a resurgence was further added to by the announcement of the airbus a3xx project in 1994 a fully double deck four-engined airliner with a design akin to that of the unsuccessful md12 while at the same time boeing was in development of a potential replacement for the 747-400 called the new large airplane project which would have resulted in a series of models dubbed the 747-500x and 600x before being rebranded to the 747x and 747x stretch although even at the time contemporary observers noted a potential lack of demand for a new generation of quad jets as with advanced engine designs and improved reliability twinjets continued to see an exponential rise in their influence with the market dominated not only by the airbus a330 but boeing's brand new 777 of 1995 which was an immediate hit on the commercial aviation scene and was used by many carriers to replace older versions of the 747 despite the impact of the post-911 market crash which saw passenger numbers plummet and fuel prices spike work continued on the boeing and airbus quadjet projects with the a3xx now dubbed the airbus a380 eventually being brought to fruition in april 2005. the
aircraft with a capacity of 525 passengers being the largest commercial airliner ever put to work and was immediately lapped up by several influential carriers across the globe most notably emirates who created a vast network of a380 routes from their dubai hub which serve nearly every major center in capital city in the world boeing's project followed in february 2010 where after numerous delays the improved 747 model arrived on the scene as the boeing 747-8 which came as both a freighter model and the intercontinental passenger variant the airliner keeping the same basic structure as the preceding 747-400 but featuring an extended fuselage length and a sweeping wing which is thicker and deeper so as to hold an increased fuel load while wider rate wing tips provide for additional lift and optimal fuel efficiency for the model all examples being powered by general electric gen x 2b 67 engines producing 66 500 pounds of thrust and capacity ranging from either 467 passengers or 46 cargo pallets sadly the launch of these two models despite their technological feats clearly illustrated how far the quad jet had fallen in terms of its place on the commercial aviation market the boeing 747-8 being the most egregious example as despite showing capacity that was far greater than the nearest boeing 777 or airbus a330 model passenger airlines opted to avoid this model simply based on its lower fuel efficiency the intercontinental variant only ever selling 48 units between 2011 and 2017 while the more popular cargo variant saw widespread use with the world's many freight carriers seeing 107 of these machines delivered over the course of the model's 11-year production life the airbus a380 by comparison was far more successful but only in the form of a marketing ploy its incredible interior space being used not only for larger numbers of economy seating but also for prestige onboard suites with double beds and other luxurious amenities the inability of the a380 to garner the same interest as preceding generations of quadjets being evidenced in the fact that its many proposed variants including a dedicated freight variant and stretch fuselage options were never taken forward nor was the model inducted into the neo or new engine option program a sweeping upgrade to airbus models in order to increase their operational efficiency through improved wing designs and engines therefore with the 747-8 struggling along with poor sails and the a380 being seen by carriers as more of a vanity project rather than a viable alternative to widebody twin jets the discontinuation of both models was certified and came first for the a380 in february 2019 when it was announced after its main customer emirates agreed to drop an order for 39 of the aircraft replacing it with 40 a330 930 a350 900s that all production would cease by 2021 the very last airbus a380 alpha 6 echo victor sierra making its maiden flight from toulouse on march 17 2021 before being delivered to emirates on december 16th of the same year while due to very low resale values caused by the incredible size and specific nature of the model retired examples have seen very limited second-hand use and instead face scrapping after only eight to ten years of operation as for the 747-8 in july 2020 boeing announced that once the final 16 orders had been fulfilled the 747 program would close after 52 years the end of the project justified by demand for four-engined airliners having been flat for several years while the lion's share of the aircraft's production went to the freighter variant the final four 747-8 being delivered to atlas air during the summer of 2020 while many 747-8 specifically the passenger variant went undelivered to their prospective customers before even taking flight in revenue earning operation these units being placed in protected storage at boneyards such as victorville in california awaiting an uncertain future today the sun is truly beginning to set on the era of the quadjet in commercial aviation the downturn in traffic during the 2020 to 2021 covert pandemic seeing a mass kill of four-engined airliners by many of the world's largest carriers including airbus a340s and a380s as well as boeing 747-400 and 747-8s the older a340s which left production in 2011 going largely to scrap though the 747 400 and 747-8 are able to find new lives in the role of cargo aircraft while future prospects have already begun seeing long and short-term retirement plans be enacted for those quadjets still remaining in service with emirates having been the last airline to purchase the a380 initiating a retirement scheme from as early as september 2019 proposing to withdraw the oldest examples for use as spares donors before seeing all models out of work by 2035. as with tri-jets the quadjet's rise and fall is one that was once again caused by necessity requiring additional power plants so as to overcome the 60-minute rule and the limitations of contemporary jet technology only for advancements in this field to allow for the exponential rise of twin jets which rapidly displaced the quad jet due to their ability to marry improved fuel economy with a capacity not too dissimilar to that of the gigantic 747 and its kin leading to the inevitable decline of these model types and the undeniable fact that these graceful machines regardless of their technological and stylistic achievements will soon be facing their final demise you
2022-07-20