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Thread: Gyro Horizons ...... question

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    Default Gyro Horizons ...... question

    Before Gyro Horizons had degrees of pitch added to their center display (as seen on contemporary Gyro Horizons etc), did pilots through operational experience and rough rule of thumb gauge their degree of pitch-down in level flight by observing where the horizon line sat relative to degree gradients on either side? (see image link) http://ww2talk.com/index.php?attachm...4600f8c4d46c13

    To clarify, the red lines I added to the image would not be perfect 10-degree gradients as the horizon line moves up the display. As the numbered arc narrows inward and upward the 10-degree pitch values are likely closer to 9.8, 9.7 degrees. The Sperry Gyro Horizon pictured is a No. 643710 found in early model B-17, B-24, B-25 etc, later versions had a caging knob. I found one reference in the B-24 D pilot training manual as to best climb attitude which suggested "keeping the miniature airplane approximately 1/8th inch above the horizon bar" which roughly equates to 10 degrees or so. Has anyone read a similar statement in other WW2 pilot training manuals?
    Last edited by ChrisW01; 16th June 2020 at 07:57.

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    Default Re: Gyro Horizons ...... question

    Hi Chris,

    A.P. 123 Instrument Flying (Standard Panel) from September 1941 says the AH 'indicates climb and dive up to 60 degrees and bank up to 90 degrees' (p5). Later, it says 'Ex 3 - find the correct position of the A/H for level flight at:
    (a) Normal cruising boost.
    (b) Slow cruising boost.
    (c) Maximum cruising boost.
    ...open the throttle until the required boost figure is obtained and then adjust fore-and-aft attitude on the A/H to give level flight as shown by the Vertical-Speed Indicator if the Mark 1B or subsequent mark is fitted' (p11).

    (p13) - 'Demonstrate the position of the A/H which represents maximum safe climbing attitude. In most aircraft this will be with the miniature aeroplane only about 1/4 inch above the top horizon bar. Many pupils will be surprised to find this angle so small.'

    p14 'This fault ['see-sawing' of airspeed] can and must be entirely eliminated by the instructor insisting on the pupil climbing by attitude on the A/H, and not by airspeed alone.'

    Subsequent lessons include similar demonstrations of pitch attitude by A/H for other phases of flight (descent, landing approach etc), with cross-reference to VSI or the Sensitive Altimeter. There is no mention of units of scale for A/H pitch, only of the need to fly by attitude and understand the attitude associated with different climb/sink and boost settings.

    HTH,

    Richard

  3. The Following User Says Thank You to Richard For This Useful Post:

    ChrisW01 (16th June 2020)

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    Default Re: Gyro Horizons ...... question

    Much appreciate your reply Richard, thanks!
    Sent you a PM.
    Chris.....

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