Evening star. [volume] (Washington, D.C.) 1854-1972, 1919-06-15
DEPICTS imagined
TRANSSEA FLIGHT
Lieut.. Brown Anticipates
Success in Vickers-Vimy
Bomb Flight.
TO USE Marine METHODS

to air flight, Lieut.. Arthur Whit
ten Brown expects to fly across
the Atlantic in the Vickers-Vimy
machine. piloted by Captain Jack
Alcock, and to make a landfalP'
within twenty or thirty miles of his
objective in Ireland or England.
Was American Engineer.
Lieut.. Brown was an American
electrical engineer before he join
ed the British flying service in
1914. He has described in a state
ment which he has prepared for the
Associated Press an interesting de-
scription of the difficulties encoun-
tered in a transatlantic flight and
the methods by which he hopes to
overcome them.
I'm flying an airplane over large
bodies of water such as the Atlantic
ocean. where the pilot may be for
hours out of sight of any landmarks
by which he could judge his position,
1t is to the methods of navigation
marines that the pilot turns to learn
where the location and the course
to his destination is" writes Lieut..
Brown.
Unfortunately difficulties arise
from the start in applying these
because the airplane is at the mercy
of the wind and appears to move in
the direction in which the wind blows
with the speed at which 1t is blown.
In the second place the speed of the
airplane is from five to ten times
that of the commercial vessel
Special Charts Used.
1.-THE high speed of the airplane
to l.
observations for position. and this in
turn makes : it undesirable to use
the slow, albeit accurate. means of
calculation ordinarily employed. In
consequence, special charts have been
devised for use with the sun or stars
which enable the pilot to fix his po-
sition in very short time, although
not with the accuracy demanded in
marine work. With the aid of these
charts. together with a sextant for
observing the sun or stars. a chronom-
eter and compass, the pilot should
be able to make a landfall within
twenty to thirty miles of the desired
point.
This. however. he will not be able
to do unless he keeps careful watch
on the direction and strength of the
wind, which may alter between his
observations and without his knowl-
edge. In order to check this, an in
strument known as the drift indi-
Gator has been devised. by means
of which the pilot can ascertain the
direction of the wind and the speed
at which he is travelling over the
ocean. so long as he can see the
ocean and the flares of smoke bombs
which he drops into it for the pur-
pose of making his observations of
drift.
Apt to Drift From Course.
Should the pilot be flying in clouds
SO that he can see neither the ocean
nor the sky. he can only depend upon
his compass, which gives direction
only. Under these circumstances he
may drift many miles out of his
course without being aware of it,
unless he employs a late develop
ment of wireless telegraphy, by
hearings from two or more land
stations and fix his position at the
point OF intersection. For short dis
tances this method has proved its
reliability, but it has yet to be proved
that II Is suitable for such journey
as the transatlantic flight until
further improvements have been
made In the apparatus employed.
Imagines Flight From st. Johns.
Let US take a flight from St. Johns
steering the airplane along the short
est route for Galway bay, and start.
ing some time in the afternoon.
before leaving the ground the
drift indicator is set to the required
course Is worked out which will allow
Ior the drift caused by the prevailing
wind. After rising into the air and
gaining sufficient height the airplane
Is set on the compass course. and this
course Is then corrected until the de-
"a ha I'D
made good. The time of passing over
the coast is noted and the speed over
the ground is measured. The direc-
ton and speed of the wind at the
neisht OF the airplane are calculated
and the drift Indicator carefully
watched so as to detect any altera.
ton and to make the necessary cor
rections.
During the first hour the height of
the sun above the horizon is meas
ureo Dy means of the sextant, the ex-
act time of the observation being
noted. The special chart is then
brought into use, and if there has
Deen no error in the allowance for
wind 1t shows exactly what point has
oeen reached on the desired track to
galway bay. This is then checked I'M
with the position which should have
been reached according to the meas.
ured ground speed, and in the short
distance traversed during the first
hour there should be no appreciable
discrepancy.
Wireless Messages Come.
The navigator now has time to
busy himself with settling down for
the journey after the hurried prem
arations at the start, and to nav
little attention to the many calls
coming over the wireless BY this
time he Is almost out of range with
mis- sending apparatus, but signals
continue to come in bearing MESA ees
OF cheer. and perhaps some humorous
suggestions as to conduct en- route,
to which, unhappily, the appropriate
replies cannot be sent.
Another hour passes, and 1t is time
for another observation. This is taken
in the same way as the first, and as
the hours slowly pass. so the distance
increases. and the data obtained from
the observations pile up and give one nm
increased faith in the instruments de-
vised by man.
Night Observations Best.
Might comes on, and the stars be-
gin to peep out. This Is the best time
for the navigator, for there are many
stars and observations on two or three
OF them give him more accurate
position than he can obtain from the
single observation afforded by the sun.
1t Is too dark to see the surface of the
ocean and the drift indicator cannot
be used unless flares are thrown out.
h1lt fre0uenf Ohsorva ffops 70 a.