New-York tribune., 1919-06-15

the Azores. Presumably they were
unable to establish their bearings.
This difficulty would not have been
met had the seaplanes been equipped
with radio direction indicators, the
history of which is contained in an
article in "The Daily Telegraph"
London. The writer says:
'In clear weather and in the daytime
there is no difficulty for a trained
aviator or navigator in following a
definite course or ascertaining the
exact position of his plane or ship.
When fog or heavy clouds are present
the case is quite different, and the
aviator is in more serious difficulties,
for it is almost impossible to obtain
any information from a compass in the
absence of accurate knowledge of the
amount of drift. A light mist, which
during the hours of daylight would not
prevent observations, might be suffi-
cient to obscure lights or other signals
at twilight or during the night
Recent accidents to large planes,
which have been compelled by engine
trouble to land hastily, indicate the
desrability of enabling these machines
to find properly equipped aerodromes
in case of need. Some years ago sue
cessful experiments were made with
what was known as the radiogonio-
meter, and it was found to be possible
10 detect with fair accuracy the direc-
ton from which electric waves were
arriving. AS with so many valuable
appliances, the driving force of urgent
military necessity has led to great i'm
provements in the sensitiveness and ac-
curacy OF these devices, and some ap-
paratus of this description will be
almost indispensable when commercial
aviation begins to develop.
The principle upon which the ap-
paratus depends is that with properly
shaped radio telegraphc antenn@
there is an unsymmetrcal distribution
of the radiated energy, so that what
may be termed an electric beam may
be sent in any desired direction By
e similar receiving arrangement the
direction in which this beam is COM
ing may be determined by the pilot
Of a plane, and by using distinctive
I. A..
can be Indicated"
Going further into the construc-
tion cf this new device, the writer
declares:
The sending and receiving antenna
take the form Of narrow rectangular |
coils containing q few turns of wire
and one Of the most important ad-
Vantages derived from recent research |
is the reduction in the size of these |
corls owing to the increased sensitive
ness obtanable by the use Of modern |
receiving devices depending upon the |
ampllfication and rectihcation of oscil- |
latlons by means OF thermionic valves.
The maximum amount of energy is i
radlated from the rectangular coil in /
the plane of the coil, and if the plane |
OF the receiving coil be at right angles
to the plane Of the sending coil the |
received energy will be a minimum. 1t
is obvious that either this position or
that obtained by rotating the receiving
coil through 90 degrees, when the
will
can be used for fixing direction.
FOR determining a position it would !,
be necessary to take two bearings, al
most simultaneously, from stations in |
known positions on the map, when the
usual triangulation and knowledge of |
the altitude would fix the position of
the observer. While it is possible to
use the coils in the position where a
minimum of sound is obtained in the
receiving telephone this cannot con-
Vehlently be done in an aeroplane, where
extraneous sounds prevent the accurate
determination Of the required point.
II is, therefore, Necessary to use the
COLI IN the position of maximum sound,
and special arrangements can be made
on large planes to enable this to be
done Six coils, altogether, are pro-
vided, and four of these are mounted
In Axed positions on the struts and
wings. Two coils are arranged with
their planes parallel TO the direction of
movement and two others are at right
angles to these.
IF the plane be directed 80 that the
sound in telephones connected to valve
circuits linked electrically to the rst
set of coils is kept at maximum
strength, the machine can be steered
directly toward an invisible point from
winch the radiation is being sent AS
tnese coils are fixed, the plane itself
must be moved so as to make the neces-
hary observations for locations of posi-
ton, and in order to remove this diff
hcuity second pair Of coils is fitted
inside the fuselage, and connected BY
CORDS, 80 that the coils can be rotated
'n'o any position. The aeroplane pilot
OF the future will have to take bear
ings with his radogoniometer when
ne mas lost his way, just az the captain
oi Ehip watches for the lights which
indicate the safe course for harbor.
Naturally great deal depends on
'he accuracy with which the bearings