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Region of reversed command

Having gotten James Albright’s “Flight Lessons” five-volume series as Christmas present, he mentions early on the “region of reversed command” and that got me thinking that how it is laid out in the book and also taught during my PPL course is a more convoluted explanation than necessary.

Thinking about it, I would rather explain it that you need more and more angle of attack to increase lift the slower your airspeed is, and since the induced drag increases with lift, and the thrust vector component aligned with the flight path also decreases (probably with the cosine of alpha as first approximation), you need of course more power to fly slower … no “reversion” since airspeed is a consequence of my actual control values of angle of attack and power setting (come to think of it, I probably just invented “pitch and power equals performance” again).

Does that make sense?

EHRD / Rotterdam

Sebastian_H wrote:

no “reversion” since airspeed is a consequence of my actual control values of angle of attack and power setting (come to think of it, I probably just invented “pitch and power equals performance” again).

Yes reverse command still mean picth & power = performance, the performance will be “as expected” for low angle of attack where cos(alpha) = 1, for cos(alpha) => 0 you need infinite power or “performance is reversed”

Another way is: Performance = ASI & VSI, near stall with constant power you can’t fly +VSI while ASI decreases and only way to get +VSI is to increase ASI (another way to look at it via U-shape curve for speed vs power/drag)

Practically, the concept only matter to explain how stall recoveries works (it can’t be done with power ) and how one stretch it’s glide?

The other example is “early lift off” or takeoff with full flaps near ground and high angle of attack, one can get stuck in that “reversed regime” forever*: no way to clean flaps, no way to accelerate with full flaps, no way to push the nose down into the ground to accelerate and no way to lift the nose away from the ground to climb….

*Runway has limited length though

Last Edited by Ibra at 12 Jan 10:23
ESSEX, United Kingdom

I am probably not understanding this but anywhere on the back of the drag curve you need more power to fly slower.

Whether this is “reversed command” is debatable; control surface authority is supposed to be not just monotonic but reasonably progressive, on any certified aircraft. @pilot_dar will know more.

Administrator
Shoreham EGKA, United Kingdom

Push the yoke, cows get bigger

Pull the yoke, cows get smaller…then bigger

Oxford (EGTK)

RobertL18C wrote:

Push the yoke, cows get bigger

Pull the yoke, cows get smaller…then bigger

Can’t get simpler than that

ESSEX, United Kingdom
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