"Mxsmanic" ... wrote in message
...
In simulation it seems that flying slow with flaps extended makes the
aircraft more prone to exaggerated movement for a specific control
input, especially in larger aircraft. Is an aircraft inherently less
stable at slow speeds with flaps extended? If so, is it just because
the flaps are out, or is it the slow speed that does it?

Hm... Slow flight is accompanied by soft-feeling controls and less control
authority (i.e. you have to put in more input to get the aircraft to
respond, not less). By the same token, you have to put in more control to
stop the plane from rolling (or whatever) once started, so that might be
what is giving you that impression. Dunno.

When flying around a city for fun at low altitudes (2000-3000 feet), I
often fly with full flaps and throttles near idle. It makes it easier
to go slow and enjoy the view, but I also get the impression that the
envelope of safe maneuvering is smaller in this configuration. But I
don't know if it's the flaps that do that, or the slow speed, or
perhaps both.

I'm not quite sure what you mean by 'envelope of safe maneuvering.' You
can't go as fast with flaps extended, because something might break, but you
can fly slower, because of the additional lift.

When I first tried simulation (many years ago now), I was surprised by
the drag effect of flaps. I had read about it but I didn't realize it
was so significant. I finally understood why I had heard commercial
pilots increasing engine speed while approaching a runway on landing.
I find myself doing the same thing, to maintain altitude mainly, and
also because it seems to improve flight characteristics if one flies
with more power (?), as opposed to just gliding in at the slowest
possible speed.

I'll have to take your word for it -- I've never flown a big airplane, real
or simulated. In smaller airplanes where the propwash flows over the control
surfaces, your elevator and rudder are more responsive at higher RPMs.

Tom Young