Evening star., 1928-12-14
FOG LANDING SEEN
POSSIBLE BY RADIO
Or. AIexanderson'S AIternatoT
Enables Flyer to Know
Position.
BY MARTIN CODELL.

Radio will be the medium for making
air navigation safe. It will enable the
aeronaut to know precisely how higl
he is flying where his craft is at given
moment and what he shall do for safe
landing under poorest conditions OF
visibility. Such radio aids are quite
apart from the obvious benefits to be
derived from communication while in
fight possible for aircraft as for sea-
craft only by means of radio.
The foregoing in substance, are the
views of D.. E. r w. AleXanderSon, IA
nous inventor of the radio alternator.
They were stated in an interview while
he was here to read a .,aper on his
newly discovered method of measuring
precise attitudes by means of radio
echoes at one cf the subseSsions of the
International Civil AeronauticS Confer
ence.
DR.. Alexanderson first presented the
scientific phases of his newly diScov-
cred principle and method of measuring
the exact height of an aiIplane above
ground at a recent meeting of the Ma
tional Academy of Sciences at Schenec-
tady. He said he came to discuss its
practical application with the practical
aeronautical men who are gathered here
from all parts of the world Dr. Alex
anderson said he has been using fly
ing laboratory over Schenectady for his
researches.
Fog Landings Dangerous.
Barometric altimeters of the type
now used on aircraft indicate the height
above the last level to which the in
strumentS have been adjusted, DR..
AlexanderSon said Thus such level
changes as mountains and valleys are
not always indicated, and flyers in
clouds and fog are in constant danger
unless they know their location with
respect to the ground and the general
nature of the terrain. Landings in fog
are a constant menace.
1t was at the request of the research
directors at Wright Field that DR.. Alex
anderson last Summer undertook inveS-
legations into the possibilities of radio
for solving his problem. He discovered
a principle and method after repeated
trial and error during flights in plane
chartered for the purpose and especially
equipped by the General Electric Co.
He found that by measuring the infin-
itesimal time it takes for the radio echo
or the reflection of the wave sent out
fro.l the plane it is possible to deter
mine absolute attitudes.
A flyer approaching steep activity
or mountain could Immediately be
warned of the danger of humping" it,
even if he could not see it, because the
altitude reaching would always be in
relation to the geographical formation.
The fundamental principle, according to
Dr. Alexandersons paper, is the same
used for depth sounding to enable the
maritime navigator to fix his course in
fog.
Safe Landings Possible.
DR.. Alexanderson concludes with the
statement that if measurements of alti-
tude and position can be combined with
a mechanical landing device touching
the ground at 10 to Is feet it is con-
ceivable that safe landings may be made
in fog without any vision of the
landing field.
The only other radio paper presented
at the international air parley was one
on uses of radio as an aid to naviga-
tion on the fixed airwayS. It was pre-
pared and read by Dr. j. H. Dellinger,
radio chief of the Bureau Of Standards.
It told Of activity in developing the
beacon methods of guiding airplaneS
along fixed airways during fog and
other low visibility periods.
The radio beacon system, it states,
guides the airplane along the airway
regardless of fog, informs the pilot of
the distance passed over, and brings
him to the Ian 9ng field. Apparatus
has already been developed for this pur-
pose, largely in the Government labo-
ratorieS.
DR.. Dellinger expresses the belief
that not only the airways of the future
will use this direction finding, but that
such undertakings as transoceanic
flights and explorations will utilize it
to reduce the hazards of adverse
weather.
(Copyright, 1928, by North American
Newspaper Allance.l