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Thread: Boeing. Will it rebound?

  1. #36
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    Default Re: Boeing. Will it rebound?

    I have to balance what you post against something else I read which said the new larger engines mounted farther forward relocated the CG farther forward, however, the center of lift (wings) was not relocated correspondingly. I had considered the lack of space in the airframe required to accommodate taller landing gear, but did not want to lengthen my post in order to mention that. Your "cheaply as possible" may pretty well tell the tale. I did mention "bean counters", eh?.

    Quote Originally Posted by Tom Wilkinson View Post
    The problem is actually the opposite of what you said. The larger engines mounter further forward actually created lift fret her forward during high angles of attack which then required the nose down trim to correct. The landing gear issue was not to match height, it's just the fact that there isn't room for taller landing gear. Boeing was really just tryin to re-engine an existing airframe as cheaply as possible.

  2. #37
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    Default Re: Boeing. Will it rebound?

    Quote Originally Posted by Nicholas Scheuer View Post
    I have to balance what you post against something else I read which said the new larger engines mounted farther forward relocated the CG farther forward, however, the center of lift (wings) was not relocated correspondingly. I had considered the lack of space in the airframe required to accommodate taller landing gear, but did not want to lengthen my post in order to mention that. Your "cheaply as possible" may pretty well tell the tale. I did mention "bean counters", eh?.
    The larger engines are mounted further forward, but that isn't causing a nose down CG condition. The problem is with a high angle of attack, the engine cowl actually starts producing lift forward of the wing creating a worse nose up condition. That's why MCAS forces the nose down. If the issue was as you stated MCAS would force the nose up. In this situation the aircraft "thought" it was in a high angle of attack (erroneous AOA sensor) so if forced the nose down, based on MCAS control law. The airplane does not have an inherent nose down problem from engine location.
    Tom

  3. #38
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    Default Re: Boeing. Will it rebound?

    Is this country made of money or what?
    $200million to put 15,000 lbs of fuel in the air.

    https://www.navyrecognition.com/inde...5-billion.html

    The U.S. Navy has estimated that the developing and procuring of a fleet of 72 MQ-25 Stingray unmanned aerial refuelling aircraft will cost $US 15.2 billion, nearly $US 2 billion more than the original estimate of $US 13.3 billion.
    .
    .
    .
    The inclusion of the unmanned MQ-25 Stingray aerial tanker into the U.S. carrier air wing could increase the effective strike range of the strike fighters aboard aircraft carriers by up to 400 nautical miles. This USA tanker could be able to deliver about 15,000 pounds of fuel at 500 nautical miles from the carrier to the air wing’s strike fighters, which would almost double their operational range.

  4. #39
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    Default Re: Boeing. Will it rebound?

    Quote Originally Posted by Tom Wilkinson View Post
    The larger engines are mounted further forward, but that isn't causing a nose down CG condition. The problem is with a high angle of attack, the engine cowl actually starts producing lift forward of the wing creating a worse nose up condition. That's why MCAS forces the nose down. If the issue was as you stated MCAS would force the nose up. In this situation the aircraft "thought" it was in a high angle of attack (erroneous AOA sensor) so if forced the nose down, based on MCAS control law. The airplane does not have an inherent nose down problem from engine location.
    Can anyone actually cite a situation in which a 737 Max even came close to a stall? Wouldn't it be nice if someone published pitch / moment graphs of every commercial jet airliner now flying? Do you suppose anyone would examine them prior to declaring a particular aircraft unsafe?

    As I tried to point out in the other thread, the horrible and glaring deficiencies of the MCAS design brought the two aircraft down, not a fundamental lack of airworthiness of the aircraft, as so many want to claim.

  5. #40
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    Default Re: Boeing. Will it rebound?

    Quote Originally Posted by Dave Wright View Post
    Can anyone actually cite a situation in which a 737 Max even came close to a stall? Wouldn't it be nice if someone published pitch / moment graphs of every commercial jet airliner now flying? Do you suppose anyone would examine them prior to declaring a particular aircraft unsafe?

    As I tried to point out in the other thread, the horrible and glaring deficiencies of the MCAS design brought the two aircraft down, not a fundamental lack of airworthiness of the aircraft, as so many want to claim.
    I agree with you on that. The unsafe part is tying the system to only one sensor where a failure can cause a pitch down at low altitude severely limiting your recovery options.

    The reason for the system being installed will likely never occur in commercial service, that's the real tragedy of it.
    Tom

  6. #41
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    Default

    Another article that talks about the nacelle lift characteristic as well as the inability to manually trim.
    http://www.b737.org.uk/mcas.htm#mantrim


    Sent from my iPhone using Tapatalk
    Tom

  7. #42
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    Default Re: Boeing. Will it rebound?

    The Financial Times is reporting on the flaws in the simulator. It keeps getting worse for Boeing:

    https://www.ft.com/content/494354da-...2-f785092ab560


    A spokesman for the American Airlines pilots union, Captain Jason Goldberg, said the latest revelation had further undermined pilots’ confidence in the aircraft manufacturer. “Again we seem to hear one thing from Boeing and then months later we hear something else. Boeing seems to have a penchant of telling us one thing in private and another in public.”
    "Travel is fatal to prejudice, bigotry and narrow-mindedness, and many of our people need it sorely on these accounts. Broad, wholesome and charitable views of men and things cannot be acquired by vegetating in one little corner of the earth all one's lifetime" Mark Twain... so... Carpe the living sh!t out of the Diem

  8. #43
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    Default Boeing. Will it rebound?

    Quote Originally Posted by The Bigfella View Post
    The Financial Times is reporting on the flaws in the simulator. It keeps getting worse for Boeing:

    https://www.ft.com/content/494354da-...2-f785092ab560


    A spokesman for the American Airlines pilots union, Captain Jason Goldberg, said the latest revelation had further undermined pilots’ confidence in the aircraft manufacturer. “Again we seem to hear one thing from Boeing and then months later we hear something else. Boeing seems to have a penchant of telling us one thing in private and another in public.”
    Paywall in the FT story.
    Is this similar?

    https://apple.news/As2ABg3kcMl2penT5Osgk4Q


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    Last edited by Tom Wilkinson; 05-18-2019 at 09:09 PM.
    Tom

  9. #44
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    Default Re: Boeing. Will it rebound?

    Quote Originally Posted by Tom Wilkinson View Post
    Paywall in the FT story.
    Is this similar?

    https://apple.news/As2ABg3kcMl2penT5Osgk4Q


    Sent from my iPhone using Tapatalk
    I've hit the FT paywall too now... but similar. The FT story added the bit about what the pilots thought of Boeing... which wasn't very complimentary.
    "Travel is fatal to prejudice, bigotry and narrow-mindedness, and many of our people need it sorely on these accounts. Broad, wholesome and charitable views of men and things cannot be acquired by vegetating in one little corner of the earth all one's lifetime" Mark Twain... so... Carpe the living sh!t out of the Diem

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