Precession of gyros
RESTRICTED
5.
Precession
of Gyros.
6.
Apparent
Easterly
P. acession
Fig. 43
to the push, but a point ninety degrees beyond in
direction of
the wheel's rotation, will move
instead.
In a previous lesson the kinds of
precession
were
considered, and it is necessary to review
them.
Technicaily there are two kinds of precession.
They are: induced precession and apparent easter!!
precession.
Induced
precession
is caused
by a
shifting of the weight
mass of the
ion
to the spin
axis of that ayro.
gyro in
reiat-
A second type
of induced
precession, and
precession ovs. which
the maintenance man has
no control, is north hook,
which
by bearing drag and flexible lead
drag.
For purposes of study in this course only
natural or apparent easterly precession
will be
considered.
Just so long
as the gyro
behaves pro-
perly and
precession
in relation to
the turning of the earth on
its axis, it shall be
satisfactory.
In order to have normal
apparent
easterly precession it must be made
certain
that
the
balanced as to eliminate
all in-
duced
precession excepting bearing drag
and flex=
ible
drag. It will be necessary
to shift
movable weights on the gyro housing
in
an effort
to do this
and leave only apparent easterly pre-
cession.
Easterly precession can
be understood if
one's thinking is based
on the
following three
statements:
The earth rotates from West to East, and
requires 24 hours
for a complete revolution of its
360°
circumference.
spin
(b)
It is characteristic of
at any
Pay on to not of
a
gyro for its
axis to be parallel to its original position
moment of time.
Gravity operates at all times to hold
all bodies and things perpendicular to the earth.
In Fig. 43, the earth is shown
rotating from
west to east.
дуго
been
erected to the of n
AB represents the soin axis of the
at the beginning of a precession run.
CD represents the
same spin axis about two hours later.
Notice that
the
spin axis illustrated by CD is
still para!lel
to the original starting position at AB, but is
not in the true vertical in relation to the earth's
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