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Sound Barrier (1952)

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  • BVS
    replied
    I will have a read of that thanks BK
    Many of the airliner control incidents have happened whilst flying on autopilot,I remember many years ago there was a 707? cruising at high altitude (41,000' ?) on autopilot,one of the outboard engines wound down very subtly and gradually without causing any flight deck captions/warnings - the autopilot just kept feeding in gradual rudder and aileron inputs to keep the a/c straight and level until of course eventually the control settings were outside the autopilot parameters and the autopilot disconnected LOL - all the controls snapped back to neutral and the Assymetric thrust caused by the other (still producing cruise thrust) outboard engine yawed the aircraft severely enough to invert the aircraft - the crew eventually managed to regain control at much lower altitude and there were of course injuries on board,one reason why it is always a good idea to stay strapped in whilst flying.

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  • Bonekicker
    replied
    I didn't know about the DC8 having such problems, so I'll have to read up on it. Its in many ways a classic example of a chain of events which by themselves might have been OK, but together became a disaster.

    There is of course the story in Fate is the Hunter of the DC6 which survives only because of the accidentally perfect combination of angle of attack and throttle setting, which was actually discussed the other day on DKos http://www.dailykos.com/story/2017/0...e-Hell-You-Say I suspect you'll like the 'Kossack Air Force' threads - Major Kong and others has done some great diaries.

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  • BVS
    replied
    This was not a deep stall incident Bonekicker!
    I think it might have been on a Douglas DC8 - they did suffer from problems with the Pitch Trim Compensator in early days.
    Here is an extract from an Airline Safety website which describes various control related airline accidents.

    An Eastern Airlines DC-8 crashed into Lake Pontchartrain about 5 minutes after taking off from the New Orleans Moisant Airport. All 58 on board perished. The water was only 20 ft. deep, yet only 60 % of the wreckage was recovered, because the breakup was so extensive. The FDR tape was too damaged to help the analysis. Instead, they used the maintenance records of that plane, and of other DC-8s, to conclude that the pilots had trimmed the stabilizer to the full nosedown position to counter the excessive noseup attitude that, in turn, was caused by a malfunctioning PTC (Pitch Trim Compensator) that had extended too far. Then, when the upset occurred, they could not trim the stabilizer back to the noseup position because the severe forces, generated by their pulling back on the yoke, stalled those jack screws.

    They tried putting the engines into reverse (inboard engine reversing in-flight was allowed on the DC-8), and that nearly worked; the plane was almost level when it hit the lake.

    Accident investigators found other instances of misrigging of the PTC, during the course of that investigation. A bushing was installed upside down on the Eastern plane, which would have caused the PTC to extend even further.

    As a result of this accident, modifications were made to the DC-8 stabilizer trim system:

    · A warning light was installed to alert the pilots when a PTC malfunctions and begins extending too far.

    · The nose down travel limits of the horizontal stabilizer was reduced.

    · The PTC actuator bell-crank arm was redesigned.

    · Changes in flight crew and maintenance training in how to deal with PTC unwanted extension or complete malfunctions.

    After these accidents, changes were made in pilot training. It became a “No No” to use horizontal stabilizer trim to ride out turbulence of any kind. The new procedure was to disconnect the autopilot and seek to maintain a “reasonable” – not “perfect” -- attitude, using only the elevators. Maintaining speed and/or altitude were to become secondary considerations; maintaining attitude was primary in moderate to severe turbulence, to prevent jet upset.

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  • Bonekicker
    replied
    The particular airliner type in the incident had a moving tailplane for fore and aft (pitch) trim ie the complete tailplane angle of incidence would be adjusted over a limited range to trim the aircraft for a specific speed,this is a very powerful control of course and with this particular incident the tailplane trim system 'ran away' to full nose down trim which the pilots could not overcome,however the Captain had the idea of pushing the controls forward to unload the tailplane screw jack which then allowed the system electrics to run the screwjack back the other way (when the pilots were pulling back on the controls,the aerodynamic load of the screwjack drive motor was very high and the electric motor was not powerful enough to overcome the load).
    A brave decision by the captain (and totally alien to previous training and experience) which saved all on board.
    Although of course a very different scenario to the 'Sound Barrier' scene,it reminded me of this thread
    Was that the BAC 111 or Trident? I understand those T-fin aircraft had problems early on with deep stall, and so they had to put shakers into the controls as a warning, so I was wondering if other (at the time) slightly strange characteristics manifested themselves.

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  • BVS
    replied
    Funnily enough
    We have just been on holiday,I took my old kindle with us and was catching up on some Pilot/Aircrew biographies,apparently one Jet Airliner crew did indeed have to push 'forward' on the control column to pull out of (an uncontrolled) dive.Most aircraft have a 'Trim' system which takes the 'load' off the pilots controls and allows the aircraft to fly straight and level 'Hands Off' at differing speeds.The Tailplane/Elevator trim can be very powerful and it is the trim system most used by pilots as the aircraft airspeed directly affects the 'fore and aft' trim,on most aircraft as the airspeed increases then the aircraft nose will want to rise (climb) and one must therefore keep trimming 'forward' to take the load off the control column.
    The particular airliner type in the incident had a moving tailplane for fore and aft (pitch) trim ie the complete tailplane angle of incidence would be adjusted over a limited range to trim the aircraft for a specific speed,this is a very powerful control of course and with this particular incident the tailplane trim system 'ran away' to full nose down trim which the pilots could not overcome,however the Captain had the idea of pushing the controls forward to unload the tailplane screw jack which then allowed the system electrics to run the screwjack back the other way (when the pilots were pulling back on the controls,the aerodynamic load of the screwjack drive motor was very high and the electric motor was not powerful enough to overcome the load).
    A brave decision by the captain (and totally alien to previous training and experience) which saved all on board.
    Although of course a very different scenario to the 'Sound Barrier' scene,it reminded me of this thread
    Last edited by Nick Dando; 5th June 2017, 10:54 AM.

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  • TimR
    replied
    I still have not seen this. This thread is a reminder. I will look for it this weekend

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  • Colin Smith
    replied
    I must admit that I am not amazed by this particular film, it is probably the only Lean's film I found boring with In Which We Serve. It has some powerful moments: the flying sequences, some stunning ellipsis, the troubling astronomical shots. But otherwise I found it very verbose and predictable...

    Originally posted by bertie View Post
    However like most of the earlier films they repay your attention and remind you that much of his genius resides outside of the later epics.
    I strongly disagree, that such a cliche...
    I personally give the three Ann Todd's films (and I like The Passionate Friend and Madeleine very much) for only one shot of Lawrence of Arabia or Ryan's Daughter! The cut between the matches and the sun (in both Lawrence, and Ryan), the emptiness of the desert in Lawrence, the way the editing interlace the tsarist repression and Lara's rape in Doctor Jivago, the love scene in the wood and the tempest in Ryan's Daughter , the mystery of Marabar's cave in Passage to India, the psychology of his heroes and heroines traped between desire and reality. There is as much genious in that than in Brief Encounter or the Dickens's films.

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  • Rick C
    commented on 's reply
    Alain Delon tries this trick out in "Airport 80-The Concorde" but a fat lot of good it did him.

  • BVS
    replied
    Originally posted by martinu View Post

    I knew that Chuck Yeager was the first person to break the sound barrier but I didn't know that the counter-intuitive pushing the stick forward to come out of a dive was the wrong thing to do. I thought the reversal of the control surfaces above supersonic speed was one of the most important lessons that test pilots (such as Chuck Yeager) learned. Maybe that detail from the film has become lodged in my mind as "fact" when it wasn't true. It was my dad who told me about it once, so maybe he had seen the film some time before and was passing on what he thought was the truth!
    High speed control reversal was usually caused by structural twisting of the Wing when the ailerons were deflected to 'Roll' the aircraft - so you would (say) move the control column to the right to roll the aircraft to the right but the forces on the wing structure would then cause the Wing Structure to 'twist' the opposite way and therefore the aircraft would then roll the opposite way.This would not normally happen with the tailplane (elevator) controls but D Lean had obviously heard about aileron reversal and decided to use some 'poetic licence'.
    At transonic speeds - many control surface problems were caused by shock waves moving around the wing and thus moving the control surface without any pilot input,swept back wings could keep the control surfaces inside the 'Shock Cone' but the problem was ultimately solved by using irreversable fully powered controls (ie the control surface could not be moved by external forces).
    Slow speed aileron reversal is totally different and is caused by the downgoing aileron aggravating an already almost stalled wing by increasing the angle of attack past the stalling angle so if one tries to 'pick up' a dropping wing by applying aileron then the aircraft will roll the wrong way (sometimes called Autorotate) and possibly enter a spin.

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  • Steve Crook
    replied
    Originally posted by martinu View Post

    I knew that Chuck Yeager was the first person to break the sound barrier but I didn't know that the counter-intuitive pushing the stick forward to come out of a dive was the wrong thing to do. I thought the reversal of the control surfaces above supersonic speed was one of the most important lessons that test pilots (such as Chuck Yeager) learned. Maybe that detail from the film has become lodged in my mind as "fact" when it wasn't true. It was my dad who told me about it once, so maybe he had seen the film some time before and was passing on what he thought was the truth!
    That's what films are for - to teach us things.
    of course it's true - it said so in a movie

    So the next time you're flying a supersonic plane in a steep dive you'll know that you should push the stick forwards

    Steve

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  • martinu
    replied
    Originally posted by BVS View Post
    Contrary to what is depicted in the film, the first aircraft to break the sound barrier was the rocket powered Bell X1flown by Chuck Yeager of the USAF in 1947. Yeager was present at the U.S. premiere, described The Sound Barrier as entertaining, but not that realistic – and any pilot who attempted to break the sound barrier in the manner portrayed in the film (pushing the stick forward to pull out of a dive) would have been killed. Because the 1947 Bell X-1 flight had not been widely publicised, many who saw The Sound Barrier thought it was a true story, and that the first supersonic flight was made by a British pilot.
    I knew that Chuck Yeager was the first person to break the sound barrier but I didn't know that the counter-intuitive pushing the stick forward to come out of a dive was the wrong thing to do. I thought the reversal of the control surfaces above supersonic speed was one of the most important lessons that test pilots (such as Chuck Yeager) learned. Maybe that detail from the film has become lodged in my mind as "fact" when it wasn't true. It was my dad who told me about it once, so maybe he had seen the film some time before and was passing on what he thought was the truth!

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  • BVS
    replied
    Originally posted by Odeonman View Post
    Very much a favourite film of mine, but I am always amused by the fact that the Nigel Patrick character takes his pregnant wife on a jaunt to Cairo without having given any thought to how they were going to get back! No wonder Joseph Tomelty's designer tells Ridgefield that Tony "hasn't got it up here" (tapping his head).
    Absolutely - but it is a nice little piece of film work : )
    It might also just be a bit of RAF type humour - possibly the Nigel Patrick character would have known about the Comet being available for the return flight but was just joking to his wife - that is the way (rightly or wrongly) I have always thought about the scene.
    Last edited by BVS; 17th March 2017, 07:47 AM.

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  • bertie
    replied
    Interesting to see this film under discussion. This would not be the first of DL's films I would necessarily go to if I wanted to renew my acquaintance with his earlier work but it is a film I enjoy. However like most of the earlier films they repay your attention and remind you that much of his genius resides outside of the later epics. The only film I do find somewhat less appealing is Madeleine.

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  • Odeonman
    replied
    Very much a favourite film of mine, but I am always amused by the fact that the Nigel Patrick character takes his pregnant wife on a jaunt to Cairo without having given any thought to how they were going to get back! No wonder Joseph Tomelty's designer tells Ridgefield that Tony "hasn't got it up here" (tapping his head).

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  • narabdela
    replied
    Originally posted by BritMovieHoncho View Post
    Fairly inane observations from The Daily Mail, July 25th, 1952

    Plus ça change, plus c’est la même chose.

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