"Rudder" is required to make coordinated rolls into banks in most aircraft.
The next question would be: is the rudder applied automatically by the
movement of the lateral controls? If not, then the pilot may have to
displace the rudder himself. Some aircraft have rudder input applied
automatically when the control column/stick is displaced.

One example of that is the B-58 which has a rudder/elevon interconnect which
uses a computer to determine when, if, how much, and in what direction the
rudder should be moved when the pilot makes a lateral input to the elevons.
In subsonic flight the rudder is normally displaced in the same direction as
the lateral input. In transonic flight the shock wave hits the vertical
stabilizer producing a "rudder" force which has to be corrected. At some
speeds the rudder is actually moved in the opposite direction since the
shockwave force on the vertical stabilizer produces more "rudder" input that
is desirable. The automatic rudder input changes more as the aircraft
accelerates to mach 2.

The B-52 is different also, in that the H model (that I flew) has no
ailerons and uses hydraulic spoilers on the top of the wings to produce the
required roll input. With no speed brakes deployed a roll input causes the
spoilers on the downward moving wing to be deployed, spoiling lift and
dropping the wing. The resultant drag makes a rudder input in that
direction to not be required. Because the spoilers are aft of the center of
lift, deploying a spoiler on a clean wing also causes an undesired pitch up.
In the traffic pattern speed brakes are normally deployed to an intermediate
position. In this case a roll input to the left will cause the left
speedbrake/spoilers to rise further and the right speedbrake/spoilers to
lower somewhat. This about eliminates the pitchup and makes flying more
stable.

That said, most aircraft require a pilot input of rudder to coordinate a
roll input. Little, if any, rudder is required once the roll stops and a
constant bank is maintained. Fancier aircraft have yaw dampers which also
reduces the required pilot rudder input. So, to answer your original
question it is necessary to change your question somewhat. Change the word
"turns" to "rolls", since most rudder coordination is necessary only while
rolling into a bank and little is needed once bank is established to further
coordinate the turn while bank stays constant. In light aircraft the amount
of wing dihedral can affect turn coordination.
--
Darrell R. Schmidt
B-58 Hustler Web Site URL (below)
http://members.cox.net/dschmidt1/

"Mxsmanic" wrote in message
...
Is it always necessary to use the rudder to execute a coordinated
turn? When I turn (in simulation) it seems that just rolling the
aircraft suffices, as long as the bank angle isn't too steep. (And
no, I don't have automatic rudder control enabled.)

--
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