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165
The Aeroplane Speaks. Fifth Edition
·
H. Barber
46
"The
Aeroplane
will
then
always
be
pointing
in
a
direction
parallel
to
A--E,
but,
owing
to
the
side
wind,
it
will
be
actually
travelling
over
the
course
A--B,
though
in
a
rather
sideways
attitude
to
that
course.
"The
distance
we
shall
travel
over
the
A--B
course
in
one
hour
is
A--D.
That
is
nearly
eighty-seven
miles,
so
we
ought
to
accomplish
our
journey
of
a
hundred
and
fifty
miles
in
about
one
and
three-quarter
hours.
"I
hope
that's
quite
clear
to
you.
It's
a
very
simple
way
of
calculating
the
compass
course,
and
I
always
do
it
like
that."
"Yes,
that's
plain
enough.
You
have
drafted
what
engineers
call
'a
parallelogram
of
forces';
but
suppose
you
have
miscalculated
the
velocity
of
the
wind,
or
that
it
should
change
in
velocity
or
direction?"
"Well,
that
of
course
will
more
or
less
alter
matters,"
replies
the
Pilot.
"But
there
are
any
number
of
good
landmarks
such
as
lakes,
rivers,
towns,
and
railway
lines.
They
will
help
to
keep
us
on
the
right
course,
and
the
compass
will,
at
any
rate,
prevent
us
from
going
far
astray
when
between
them."
"Well,
we'd
better
be
off,
old
chap.
Hop
aboard."
This
from
the
Observer
as
he
climbs
into
the
front
seat
from
which
he
will
command
a
good
view
over
the
lower
plane;
and
the
Pilot
takes
his
place
in
the
rear
seat,
and,
after
making
himself
perfectly
comfortable,
fixing
his
safety
belt,
and
moving
the
control
levers
to
make
sure
that
they
are
working
freely,
he
gives
the
signal
to
the
Engine
Fitter
to
turn
the
propeller
and
so
start
the
engine.
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