Lab
Library
Journal
Shop
Sign in
to keep
Share image
1
165
The Aeroplane Speaks. Fifth Edition
·
H. Barber
72
It
is
not
practicable
to
have
a
gap
of
much
more
than
a
distance
equal
to
the
chord,
owing
to
the
drift
produced
by
the
great
length
of
struts
and
wires
such
a
large
gap
would
necessitate.
By
staggering
the
top
surface
forward,
however,
it
is
removed
from
the
action
of
the
lower
surface
and
engages
undisturbed
air,
with
the
result
that
the
efficiency
can
in
this
way
be
increased
by
about
5
per
cent.
Theoretically
the
top
plane
should
be
staggered
forward
for
a
distance
equal
to
about
30
per
cent.
of
the
chord,
the
exact
distance
depending
upon
the
velocity
and
angle
of
incidence;
but
this
is
not
always
possible
to
arrange
in
designing
an
aeroplane,
owing
to
difficulties
of
balance,
desired
position,
and
view
of
pilot,
observer,
etc.
6.
Horizontal
Equivalent.-The
vertical
component
of
the
reaction,
i.e.,
lift,
varies
as
the
horizontal
equivalent
(H.E.)
of
the
surface,
but
the
drift
remains
the
same.
Then
it
follows
that
if
H.E.
grows
less,
the
ratio
of
lift
to
drift
must
do
the
same.
A,
B,
and
C
are
front
views
of
three
surfaces.
A
has
its
full
H.E.,
and
therefore,
from
the
point
of
view
from
which
we
are
at
the
moment
considering
efficiency,
it
has
its
best
lift-drift
ratio.
B
and
C
both
possess
the
same
surface
as
A,
but
one
is
inclined
upwards
from
its
centre
and
the
other
is
straight
but
tilted.
For
these
reasons
their
H.E.'s
are,
as
illustrated,
less
than
in
the
case
of
A,
That
means
less
vertical
lift,
and,
the
drift
remaining
the
same
(for
there
is
the
same
amount
of
surface
as
in
A
to
produce
it),
the
lift-drift
ratio
falls.
Marker
Marker
Fine marker
White-out
Fine white-out
Circle
Paint
Unmarker
Hand
Scalpel
Dice
Sieve
Purify
Undo
Redo
Start over
