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To judge the right angle of attack,
you must get used to the position of
part of the aircraft against the
horizon (usually the nose or
instrument panel), which will be
different in a left or right turn. In
practice, as long as you keep that
position, you will stay level during
Airframes, Engines & Systems 191
the turn, only checking the alitmeter
occasionally to make sure, because
you should keep the lookout going.
Remember that a bigger angle of
attack means more drag, that
requires a bigger angle, and so on.
Centrifugal force will tend to alter
the longitudinal axis of the aircraft
against the arc of the curve. Look at
the turn coordinator. A slip or skid
will alter the wing's lift-producing
characteristics and force you into
unwanted adjustments.
You need to start rolling out slightly
before the point at which you wish
to end up, otherwise you will
overshoot – you will be turning (at
an increasingly lesser rate) all the
time you are rolling out.
To roll out of a turn on a selected
heading, lead by half the angle of
bank, that is, for a 30° bank, roll out
15° before the desired heading. Use
small angles of bank for small
heading changes. Usually half the
number of degrees of heading
change is enough.
The approximate angle of bank to
produce a rate one turn may be
calculated with: (KIAS divided by
10) + 7 = bank angle. Add 5 instead
of 7 for statute miles per hour.
Use ailerons and rudder, and relax
the back pressure, otherwise the new
lift vector generated in the turn will
still be active and you will climb.
Climbing turns should be no more
than 15°. The load factor increases
with bank angle, as does the stalling
speed. Also, lift is lost with bank,
reducing the climb capability. The
right turn will be less severe, due to
torque and slipstream effects.
You can use greater angles of bank
when descending (up to 30°)
because the load factor is less than it
would be in the climb. However
nose will drop more as you roll in,
and the nose attitude will be
different as it will be lower at the
start. Avoid a steep turn and a dive,
or you will end up in a spiral dive.
Lessons involving steep turns are
more about how to recover from
them than to perform them, since
they can easily turn into spiral dives,
although they should be done as well
as possible, since they are good for
co-ordination practice. Steep turns
are officially over 30° of bank, but
they are much harder to do between
45-60°. A "normal" one, as an
exercise, is 360°, rolling out on a
specific heading (or landmark),
maintaining altitude. However, there
are many other reasons for steep
turns, such as avoiding traffic (where
you don't go all the way round) or
getting out of a valley with bad
weather in it, where you just want to
go back the way you came as quickly
as possible. A combination can also
be used to slip through the only gap
in a layer of cloud, where you want
to remain VMC, so you will be
descending as well.
Get into a good cruise, as an extra
speed margin is useful for helping
the machine cope with the extra
loads imposed on it. Do a HASELL
check (see below).
Roll into a turn and add power as
you go through about 30° (climb
RPM or higher). This will help with
the extra load and drag factors.
Use elevator back pressure to
maintain the nose attitude against
the horizon. Control the turn with
192 Canadian Professional Pilot Studies
aileron and rudder. Check the VSI
and altimeter to see if you are
keeping altitude (±100'), but this is
very much a secondary check
compared to the nose position. Do
not use back pressure alone to stop
the nose pitching down, as this will
just tighten the turn – use the
ailerons and rudder as well, to reduce
the bank angle a bit.
When rolling out, anticipate your
desired heading by about 20°. The
ideal way is to use the ailerons, relax
the back pressure and reduce power
at the same time, but in the early
stages, power can be left till last. Be
prepared to adjust the aircraft for up
to 30 seconds afterwards, so it can
settle down.
Spiral Dives
These can be entered into from
turns, or spins. The turns can be
inadvertent, as when trying to fly on
instruments without any experience,
or flying low and slow without
proper training.
　
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