Adios, Queen of the Sky!
Wasn't this exactly what afflicted the original JT9Ds on the first 747s, and which therefore seems to have taken them nearly 40 years to overcome ? I seem to remember the US used the word "Ovalise", which was not to be found in any UK dictionary !
The details changed over the years, but yes - same basic issue. Pratt has struggled to design a compressor case that didn't distort due to thermal effects or flight loads. On the JT9D-7R4 there was also an issue with case distorting during rotation at takeoff -again rubbing the compressor, causing performance loss and loss of stability margin. It was bad enough on the 767/JT9D that Boeing developed a 'load sharing' nacelle - using the nacelle structure to help support the engine case so it didn't distort at rotation.
I saw some reports that the P&W F135 engine on the F-35 has issue with compressor case stability
I saw some reports that the P&W F135 engine on the F-35 has issue with compressor case stability
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From my 30 Years of airline flying, 22 were on B747 200/300/400. It NEVER bit me. It flew like a big C172. Flew through excessive turbulence over the Andes. Hit by lightning. Flew through a cyclone. Had a few times I needed to use max roll input. You cannot believe how fast it rolled. Dependent on airspeed if outside ailerons were not locked out above 250 KIAS.
The 300 and 400 hours were CF6 powered, as were the 6 Years on the DC10. In my whole career spanning 18.500 hours I NEVER had an EF or any reason to shut one down. Testimony to the good design of GE.
The only drawback was a cramped flight deck, regarding headroom. And noisy it was too caused by airflow around the egg shaped cross section.
Happy when the noise cancelling headsets arrived....
The 300 and 400 hours were CF6 powered, as were the 6 Years on the DC10. In my whole career spanning 18.500 hours I NEVER had an EF or any reason to shut one down. Testimony to the good design of GE.
The only drawback was a cramped flight deck, regarding headroom. And noisy it was too caused by airflow around the egg shaped cross section.
Happy when the noise cancelling headsets arrived....
tdracer
Seems to be a P&W specialty, iirc the TF-30 on the F-14 was described as the worst engine case mismatch ever by some admiral, who was probably displeased with the whole project.
Seems to be a P&W specialty, iirc the TF-30 on the F-14 was described as the worst engine case mismatch ever by some admiral, who was probably displeased with the whole project.
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https://www.bbc.co.uk/news/business-53583939
including:-
Boeing said it has re-started production of the 737, but it expects the rate of manufacturing to remain low for the foreseeable future as the virus weighs on the industry.It said it hoped to be making 31 per month by the beginning of 2022 - instead of during 2021 as planned. That would be roughly half the rate of the firm's production before the grounding.
including:-
Boeing said it has re-started production of the 737, but it expects the rate of manufacturing to remain low for the foreseeable future as the virus weighs on the industry.It said it hoped to be making 31 per month by the beginning of 2022 - instead of during 2021 as planned. That would be roughly half the rate of the firm's production before the grounding.
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More Cuts / Changes at Boeing
Boeing Co slashed production on its widebody programs, delayed the arrival of its newest jet, and confirmed the demise of its iconic 747, as it reported a bigger-than-expected quarterly loss on Wednesday amid fallout from the COVID-19 pandemic.
The last passenger 747-400 delivered in 2005, but -400F were produced until 2008 (final deliveries occurred in 2009), when the line was temporarily closed to convert it for the 747-8 series production. The 747-8 series has new engines, a longer fuselage, an aerodynamically redesigned wing, updated avionics, and a higher MTOW. First 747-8 Freighter delivered in 2011, the first passenger 747-8 delivered about a year later. Production has been split roughly 2/3rd Freighters, 1/3rd passenger (i.e. "Intercontinental") - the last passenger 747-8 delivered in 2017.
There are currently a dozen or so 747-8F still to be delivered - the last delivery scheduled for 2022. The final nail in the 747 coffin was the vendor that produced the fuselage panels shuttered the factory last year (parts for the aircraft on order were 'built ahead'). Boeing would have had to either find a new vendor, or make a major investment to build the panels in-house to keep the 747-8 in production. At the current production rate (~6/year) the 747 is basically at break even - so it was determined it wasn't cost effective to make a major investment in new fuselage manufacturing capabilities.
There are currently a dozen or so 747-8F still to be delivered - the last delivery scheduled for 2022. The final nail in the 747 coffin was the vendor that produced the fuselage panels shuttered the factory last year (parts for the aircraft on order were 'built ahead'). Boeing would have had to either find a new vendor, or make a major investment to build the panels in-house to keep the 747-8 in production. At the current production rate (~6/year) the 747 is basically at break even - so it was determined it wasn't cost effective to make a major investment in new fuselage manufacturing capabilities.
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One would think Spirit wouldn't mind a bit of extra work making another type of fuselage panels.
What does this mean for the 2 new Air Force One's. 777 or 787 will just not be as iconic, or safe for they who care little about fuel efficiency.
What does this mean for the 2 new Air Force One's. 777 or 787 will just not be as iconic, or safe for they who care little about fuel efficiency.
The two new 747-8 based Air Force One aircraft are already built and in mod to the AF1 configuration (ironically the two 747-8s were originally built for a Russian airline that went bankrupt before they were delivered).
The two current 747-200 based AF1 aircraft are 30 years old, so it's a good bet that the new ones will be good through at least 2050. Who knows what might be available then?
The two current 747-200 based AF1 aircraft are 30 years old, so it's a good bet that the new ones will be good through at least 2050. Who knows what might be available then?
While the spiral staircase looked cool, as I've gotten older and less nimble, I've grown to appreciate the wisdom of that change
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spiral
They ditched the spiral staircase (I'm thinking it was when they developed the 747-400, but don't quote me on that - it may have been earlier). It seems some passengers had difficulty navigating the spiral staircase so they went with a more conventional straight staircase.
While the spiral staircase looked cool, as I've gotten older and less nimble, I've grown to appreciate the wisdom of that change
While the spiral staircase looked cool, as I've gotten older and less nimble, I've grown to appreciate the wisdom of that change
Sad to see the 747 production stop.
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Hydrogen Powered B747
Lockheed abandoned the Hydrogen Tristar because the tanks would be too bulky.
The B747 freighter could have a large hydrogen tank on the upper deck powering the two inboard engines while the two outboard engines still use JetA. Hydrogen is the future of long-haul commercial air travel...discuss...
The B747 freighter could have a large hydrogen tank on the upper deck powering the two inboard engines while the two outboard engines still use JetA. Hydrogen is the future of long-haul commercial air travel...discuss...
