Miles glide control & vacuum-operated flaps


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31 December 2008
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Forgive if I have asked this before, but here goes anyway. For many years I have been looking for more information on the vacuum-operated flaps installed on several Miles aircraft of the late 1930s. Here is a citation from an article on the Miles Monarch in the October 27, 1938 issue of Flight magazine:

Mr. Miles was one of the first British designers, if not the first, to fit split trailing-edge flaps to his machines, and in the Monarch the vacuum operated gear has been modified to incorporate an interesting safety device, which he calls a glide control. With this device a gate is provided to prevent the flaps from being raised completely in one movement, and the throttle is interconnected with the control so that, when it is necessary to use the engine suddenly either during or after the approach, the flaps move up automatically to the 20-degree position. There is, consequently, no sink and most of the drag is removed at the moment of opening the throttle. In its new form, too, the gear permits the flap position to be changed through an infinite variety of angles. In other words, the flaps are designed to give the best possible results both as lift-increasers and air brakes.

So here's what I am looking for:

1) A photo or illustration of the Miles "glide control" unit and more information on how it worked.

2) A photo or illustration on the Miles vacuum-operated flaps that would clarify the vacuum source (presumably the carburetor, but it could be a venturi) and the actuator mechanism.

Can anyone help with either of these?

Thanks and regards,

Thanks, Bailey, I had not and the article does shed some light but the text seems to contradict what I had learned from the Putnam book on Miles aircraft (that the flaps automatically retract from full to 1/2 setting with full throttle). The drawing, too, seems to contradict the written description of an interconnected throttle/flap levers at least if those are supposed to be together.

Do you or anyone else have any other leads? A clear photo of a Whitney Straight or Monarch cockpit would be very helpful.


  • Monarch Cockpit.jpg
    Monarch Cockpit.jpg
    117.1 KB · Views: 19
  • Monarch Controls.jpg
    Monarch Controls.jpg
    34.8 KB · Views: 21

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