J-20 5th Gen Fighter Thread VI

Discussion in 'Air Force' started by siegecrossbow, Sep 4, 2017.

  1. Midgie
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    Midgie Just Hatched
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    Watching the video won't confirm anything unless you positively know what the pilot is doing with their left hand. More likely whether or not it is coming in or out of power is that due to the split throttle nature of all twin engined fighters I can think of, that the pilot either decided to just use a little bit from the left to get up to speed of those he's following, or if they're coming out of power, they haven't come to idle perfectly synchronized. No crazy engine logic or programming, just manipulation of left and right engines with very fine movements from the left hand.
     
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  2. xyqq
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    xyqq New Member
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    You suggested that the pilot controls two throttles separately, but they should be locked to move together in normal operation (unless one engine catches fire, for example), right?
     
    #6152 xyqq, Dec 10, 2019
    Last edited: Dec 10, 2019
  3. Midgie
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    Correct, but saying ‘separately’ will make many people think there are two spaces apart throttle controls. The entire HOTAS throttle is designed to fit nicely under one hand, so movements back and forward will move both left and right quadrants more or less equally. In case of an engine fire you’ll have to release the normal grip and just hold the side relevant to the engine in question and bring it back to ‘off’.

    Plenty of images of Western twin engine fighter throttles show how the split works. There isn’t any lock to hold them together.
     
  4. Inst
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    Inst Senior Member

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    Most of the sophisticated thrust control can be handled by the FBW system. No need for the pilot to manually coordinate the relative thrust unless he wants to.
     
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  5. xyqq
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    xyqq New Member
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    A multi-engine plane's throttles are typically locked together unless the pilot disengages them.
    disengage.jpg
     
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  6. Midgie
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    Midgie Just Hatched
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    True for wide bodies. Not true for fighters. ‘Jetstream’ a Canadian F/A-18 documentary show some good examples of how the pilots make tiny movements on either engine to maintain AoA on approach to landing.

    Anyway this is drifting off topic. Just trying to spread knowledge.
     
  7. xyqq
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    xyqq New Member
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    A good discussion, and I do not think it is too far off the topic as J-20 is a twin-engine fighter jet.
    In the screenshot from the CF-18 documentary, the instruction is to "walk the throttles" and "don't flare". The video shows that the left hand twisted side by side to move forward a little bit a time (like walking). This actually suggests that the throttles are locked together, otherwise the movement will be a little bit too big for each engine (e.g., one forward and one backward). The FBW system probably calculates the average level of two throttles and send the signal to both engines. F18throttles.jpg
     
    #6157 xyqq, Dec 10, 2019
    Last edited: Dec 10, 2019
  8. Midgie
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    Midgie Just Hatched
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    Your statement here is perfectly correct. It doesn’t however imply locked throttles. Walking- left foot right foot. Left throttle right throttle.
     
  9. xyqq
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    xyqq New Member
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    On Su-27, those levers are used to disengage throttles for independent movement (need to open both).
    Su-27-throttle-lock.jpg
     
  10. by78
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    by78 Brigadier

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    Three interesting shots. All images are high-resolution.

    [​IMG]
    [​IMG]
    [​IMG]
     
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