The Washington herald., 1921-10-10
sChe HeuuAds
Scientific
Notes
qdCommew
MONDAY. OCTOBER 10. Is7I.

noNbAf' OcfobEh 10, 1871
NAVIGATING AIRsHIPs
Is COMPLEX TASK.
Navigating the ships Of the air IL,
much more compiler Job than steer
ing the ships Of the sea, Herbert n
Eaton Of the Bureau Of Standards
told the Philosophical Society at n,
last meeting.
Airships have had 70 carry navI.
gators OF airmen have had 70 he
come sailors, only since there hsy.
been extended flights through the
air. Aerial navigation is a new
task. although the general prin.
clples of marine navigation per-
fected during the past few cen
turies can be applied.
The chief differences betvse,
these two forms of navigation ars
the high speed OF the aircraft which
necessitates more frequent ob.er-
vstions and quicker methods Of A.
termining position. the relatively
high speed Of the wind which r,.y
carry the aircraft many miles from
its course unless the effect Ia aeon
rstely known and couuteracted. the
additional difficulties involved 4,
freedom Of motion in three instead
Of two dimensions and the fact
that the extreme accuracy REQUIRED
In navigation upon the ocean "a NOT
necessary in the air" he said
There are three principal meth
DDS Of aerial navigation: Dead reck-
! oning. astronomical observation ana
directional wireless telegrsphy.
Dead reckoning, the most unT-
versslly used. consists In determin-
ing the course and position Of sny
craft by means Of its known o.
estimated direction and speed oyer
the surface Of the earth. In Hvis-
ton this involves a knowledge Of
the heading OF the aircraft It's
speed relative TO the air. it's direc-
ton Of motion over the ground. and
its speed relative 20 the ground.
That The ground speed and the d.
rection Of motion relative to the
ground differ from the air speed
and the heading Of the craft Is due
60 the fact that the first two re-
suit from the combination Of the
motion OF the craft through the air
and the motion Of the air relative
to the ground, in other words. the
wind. Instruments have been de-
veloped TO measure all OF these
quantities.
The general principles of aerial
navigation by astronomical obser-
walton are identical with those ot
marine navigation. One strikinf diff
ference is found In the use in air
craft OF seNtants with artificial
horizons. level bubble, pendulum or
gyroscopic. owing to the fact that
in perhaps a majority OF cases no
natural horizon Is visible. Many
times, however, IL IS possible 20
utilize horizons formed by the up
per surface OF haze or clouds in
addition TO the ordinary sea horizon.
Short and rapid methods OF compu-
tation and plotting position have
been developed for the use OF the
air navigator.
Navigation by means OF the radio
direction finder is a recent develop
ment which is applicable both to
marine and TO aerial navigation. II
involves determining the direction
Of the ship from two or more wire
less stations by means Of the direc-
ton finder which measures the di-
rection in which the radio waves
are coming
These methods OF aerial navirs-
tion have been applied in whole or
in part on number OF recent
flights. These include the first At
lantic flight which was achieved BY
the L. s. navy SC-i. the heroic at
tempt OF Hawker and Grieve 10
make the first nonstop Atlantic
flight, the first successful nonstop
Atlantic flight by Alcock and
Brown and the flight OF the British
rigid dirigible R-34 from England
to America and return