The Wilmington morning star., 1947-03-02

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performance data by means of
radar and motion pictures.
Range Recommendations are
brain-childs of the Applied Physics
Laboratory on the basis of expert
ences in tests at Island Beach,
New Jersey in 1915 and later at
the Delaware range.
Harris said this measurement
system is adaptable to a large
number Of various types of ord
nance-testing.
Information is obtained from
these tests by three methods:
Camera tracking from observation
stations On the range, radar track
ing. and telemetering.
The camera and radar tracking
systems supply two independent
methods of measurement which
can be checked n against the
ether. From these measurements,
which locate the missile accurate
ly in space at any instant during
flight, it is possible to plot the
trajectory of the missile, compute
its velocity and acceleration, and
gather aerodynamic data for labo-
ratory use.
The radar equipment is of the
same type used by the army dur
ing the war, although modifi-
cations adapting it to this special
application have been made. The
range and the aZimuth and ele-
walton bearings of the model are
given by the radar and recorded
on motion picture film for analy-
sis.
The camera tracking system
gives the spatial position by sim
pie triangulation between three
stations on an accurately surveyed
two and a half mile base line.
The bird" in flight is photo.
graphed from each station by
motion picture cameras through
telescope lenses. The angle Of ele-
walton and the bearing from each
station is photographed on g sec
ond film. All films are correlated
by a central synchronizing pulse
which causes a timing marker to
be recorded on each film. 1t is
thus possible to locate the missile
at any instant by analyzing all the
films taken during that instant.
The telemetering method of Sc
curing data makes it possible to
record measurements made on the
ram JET itself while it is in flight.
This system, although much more
complicated, is similar in princi-
pie to the means Of obtaining
weather information from radio
sounding balloons. The test model
is equipped with q miniature fire.
Iquency modulated radio transmit
ter which relays informatin t the
ground receiving station from as
many as sixteen tiny electrical
measuring instruments Or sondes
during flight. These instruments
respond to temperatures and pres
sures in various parts of the
model. as well as to variations in
velocity. These data, received at
the ground station in the form OF
frequency variations. are recorded
on an oscillograph for laboratory
analysis.
Firing is controlled by the test
conductor from the control tower
near the firing ramp. Also in the
control tower is a Marine safety
officer whose responsibility is to
see that all personnel are clear Of
the ramp before the firing signal
is given. A Marine range officer
is stationed at the range tower
nearby to ascertain that the range
is clear of shipping and aircraft.
For a complete test, eleven sta
tons are manned. An intercom-
munication system permits the
test conductor to remain in two
way contact with all stations at
all times.
When the test model has been
LOADED on the ramp and is ready
to be wired for firing. the test
conductor calls each station to
check if it is ready for the run.
All stations report ready Cam
eras are turned on briefly to al
low the tracking stations to make
a zero shot on a surveyed point
as a check on the position of the
equipment.
The field is then ready for the
run.
The test conductor requests per
mission of the range officer to fire