1948 was a mere two and a half years after the end of World War II,
so military planners strategized about what a future war, if one
occurred, would look like. Two implements that had a huge effect
on the previous efforts were the atom bomb and the guided missile;
therefore, they were prominent in discussions. Germany's use of
the V-1 Buzz Bomb is a familiar example of a guided missile that
struck terror in the hearts of populations that experienced its
devastating destructive power. The U.S. developed a few missiles
of its own, particularly immediately after WWII when it had the
assistance of Werner von Braun and other notable rocket scientists
who worked for the U.S. space effort after the war. A few of the
missiles are on display today at the
Udvar-Hazy center of the National Air and Space Museum.
Thanks to Terry W. for providing this
By C.E. Chapel, 1st Lieut., U.S.M.C. (Ret.)
Consulting Ord. &
Aero. Eng. and Chief of Research & Development, Northrop Aeronautical
A new era of pilotless aircraft for war and peace
has been inaugurated. Radio and electronic equipment again plays
major role in these developments.
The atom bomb and guided missiles will be the principal weapons
for the defense of the United States of America in any future war.
None of us want war, but we all want to be ready for it if it comes.
Radio operators, radio technicians, radio servicemen, and everyone
who has the slightest interest in the broad field of electronics
should possess a basic understanding of the fundamentals of guided
missiles. Reduced to their simplest terms, they are nothing more
than new applications of vacuum tube circuits.
The "Gorgon IIC," a guided missile which can carry 1000
pounds of general purpose explosive to the target at a speed
of 100 miles per hour.
A group of guided missiles undergoing final inspection at
the Naval Air Modification Unit, Philadelphia. Each of these
pilotless aircraft is equipped with an intelligence unit
enabling it to seek out and carry its explosive load directly
to the chosen target.
Guided missile roars into the air with the aid of four Mons-auto
rockets. After expiration of the thrust of 40,000 pounds,
the rockets and sled will fall free and the "Loon" will
head out over the Pacific to its target.
Launched by Navy "Privateer" patrol bombers outside the
range of enemy anti-aircraft fire, and guided to distant
targets by radar, these Navy "Bat" bombs sank many tons
of enemy shipping. Operating on somewhat the same principle
as live bats, which emit a short pulse of sound and direct
themselves by the echoes, robot bats are guided by radar
echoes from the target. Approximately 12 ft. in length,
with a 10 ft. wing span, the "Bats" carry a heavy load of
high explosives. Two "Bats" are carried by each "Privateer,"
the Navy's giant patrol bomber.
Navy target drone, used for gunnery training of Navy personnel,
is pre-pared for a test flight by its crew.
The "Gargoyle," an air-to-ground, radio-controlled powered
glide bomb, carrying a standard 1000 lb. general-purpose
or armor-piercing payload. It can be launched from airplanes.
The "Gorgon," a guided missile resembling a freak-tailed
white shark, carries a 100-pound, specially-shaped charge
and is sent at a speed of 550 m.p.h. through air, by a rocket
The TD2N-1, an air launched target, jet powered guided missile.
The KDD "Katydid," a jet-propelled, radio-controlled pilotless
drone used as a practice target for lighter planes. The
span is 12 feet. 2.6 inches, and the length is 11.1 feet.
Equipped with a resonating jet engine equivalent to 45 hp.
and having a speed of over 200 m.p.h., it can perform all
the maneuvers of a fighter plane through radio control of
the "rudder-vators" In its V-shaped tail. It can remain
aloft 40 minutes, when a parachute packed under the forward
hatch is released by a radio signal. This turns off the
jet and allows the drone to float to earth where it can
be recovered for further use.
The KAN-1 or "Little Joe." a short-range anti-aircraft missile
designed to be launched from a shipboard catapult, with
the aid of standard rockets. It is radio-controlled, flare-sighted,
and powered by "JATO." a Navy-type solid fuel rocket.
The "Gorgon" slung underneath a Navy PB4Y-2 (Navy modification
of Consolidated-Vultee's Army B-24 four-engine heavy bomber)
ready for test flight. This is an air-to-air guided unit.
The KUW-1, "Loon," pilotless aircraft propelled by jet engine.
Another type of jet powered target missile being used by
the Navy. Known as the KDD-1 "Katydid," it is designed to
be launched either by catapult or from a target-carrying
Mockup, or exact sized model of the KAQ-1, popularly known
as the "Lark," one of the air-launched test-type guided
A radio-controlled. jet-powered target drone resting
in its launching rack under the wing of a Navy PBY. This
is a small pilotless aircraft whose flight can be made to
simulate suicide dive bombers and torpedo plane attacks.
Working on the principle that a "few hours on a drone is
worth two weeks of any other kind of gunnery training,"
the Navy went all out to develop target drones for the benefit
of its anti-aircraft gunners. These target drones were frequently
used while the fleet was on its way to and returning from
attacks against the enemy and proved far more popular with
the gunners than the usual type of towed sleeve targets
used by the Navy before the development of this type of
more realistic target.
The KUN-1, or "Gorgon IIC," a catapult-launched, jet-powered
guided missile, is shown mounted on a movable rack.
The "Glomb," Model LBE-1, a television-controlled glider-bomber
which can withstand a speed of 300 m.p.h. in a 4 G dive.
This is one of a atrio of pilotless craft of the same guided
missile family, the others being "Gorgon" and "Gargoyle."
of Guided Missile
In order to obtain a clear idea
of the design, construction, and operation of guided missiles it
is necessary to agree upon certain terms which are commonly used.
First; a missile is a weapon which can be thrown or projected through
space, such as a spear, an arrow, or a bullet. Each of these objects
is guided along its flight path at the moment of its launching,
but thereafter it is subjected to various external forces that affect
the accuracy with which it travels toward the target.
a guided missile may be defined as a weapon which travels through
space and carries within itself a means for controlling its path
of flight. This definition is broad enough to include bombs, rockets,
and even conventional airplanes. For example, a pilotless aircraft
is a guided missile having aerodynamic surfaces large enough to
supply the principal support for the aircraft in flight. Therefore,
the lessons learned from the operation of pilotless aircraft may
be applied in the design and construction of other forms of guided
Classification According to the Place
of Launching and the Target
Guided missiles may
be classified according to the place of launching and the target.
In general, they may be launched from the surface of the earth,
either from the land or from the sea, or they may be launched from
some type of aircraft. Thus, they may be launched from the ground,
from a ship, or from an airplane.
In a similar manner, guided
missiles may be classified according to their targets, which may
be ground installations, ships, or aircraft. Considering the place
of launching and the target together, the classification breaks
down into the following types: (1) Ground-to-air, (2) ship-to-air,
(3) ground-to-ship, (4) ship-to-ship, (5) ground-to-ground, (6)
ship-to-ground, (7) air-to-air, (8) air-to-ground, and (9) air-to-ship.
One guided missile may be used in two or more of the above
classifications. For example, an air-to-ground missile may be successfully
employee as an air-to-ship weapon. This does not necessarily mean
that the same type may be used efficiently for both military and
naval purposes because the launching conditions are often different
and the tactical considerations present entirely different problems.
Thus, a guided missile which can be launched from a heavy bombardment
airplane may be too large and heavy to launch from a comparatively
small carrier-based airplane. In the same manner, a missile which
may be fired from the ground against airplanes may be too large
and heavy for a ship to launch against enemy suicide airplanes.
Furthermore, in many instances it would be a waste of valuable armament
to launch a large guided missile against a relatively small or unimportant
target when the same weapon may be needed later for an appropriate
Classification According to Method of Propulsion
A missile may be dropped from an airplane like
a rock, in which case it merely possesses the altitude and speed
given to it by the flight of the airplane, and it is brought to
earth by the force of gravity. It may be fired from a gun aboard
an airplane, it may be launched from an airplane by means of a rocket,
or it may be given an initial acceleration by means of a rocket
motor and thereafter be self-propelled.
It is obvious that
any of the methods used for launching a missile from an airplane
can be used for ground launching except a method which depends on
the force of gravity. Of course, in theory, a missile could be launched
from a high tower erected on the ground but structural limitations
make this foolish, although it must be remembered that this method
was used in ancient times.
We now come to a method of propulsion
which is suitable for missiles launched from either the ground or
the air, and this is the use of self-propulsion, which simply means
that the missile contains a power plant of some description. The
power plant may be a reciprocating engine with a a propeller, a
gas turbine with a propeller, a turbojet motor, a ramjet motor,
an aeropulse motor, or any other kind of power plant which will
drive the missile along its path through the air.
may or may not have aerodynamic surfaces, that is, it may or may
not have wings, ailerons, a rudder, an elevator and other surfaces
for controlling its flight path. For example, glide bombs have been
used, both with and without wings and it is possible to use rockets,
either with or without wings. Pilotless aircraft using conventional
types of power plants are too slow to be effective and too large
to escape enemy detection and destruction, hence they may be eliminated
from our classification of modern, practical, guided missiles. Bullets,
bombs, and artillery projectiles as we have known them in the past
should be eliminated from our thinking because they are not adaptable
to self-propulsion. In general, modern guided missiles fall into
two principal classes: (1) Rockets, either with or without wings,:
and (2) Pilotless aircraft with some form of jet propulsion.
Classification According to the Method of Control
Before we approach the control of guided missiles,
we should have a basic understanding of the control of conventional
airplanes. The aileron is a hinged, movable portion of a wing, the
principal function of which is to impress a rolling motion on the
airplane. By raising one aileron and lowering the other, the pilot
can roll his airplane to the right or left. The rudder is a movable
surface hinged to the trailing edge of the vertical stabilizer,
used to steer the airplane right or left. The elevator, usually
hinged to the trailing edge of the horizontal stabilizer, is used
to raise or lower the nose of the airplane in flight. These three
types of control surfaces control the three fundamental rotational
motions of an airplane.
In order to relieve the pilot of
work, the autopilot was developed. In its simple form, it may be
set by the pilot on a course and thereafter it operates the ailerons,
rudder, and elevator to keep the airplane on a straight and level
path. Autopilots used in World War II were either hydraulically
or electronically operated and where used in flight but were not
extensively used for take-off or landing. However, autopilots are
now developed so highly that they may be set on the ground and used
from take-off to landing without the intervention of a human pilot
in the operation of the control surfaces.
Coming back to
guided missiles, in World War II, the Germans used the types known
as V-1 and V-2 with considerable success. The V-1 was a pilotless
aircraft and the V-2 was what is technically described as an elliptical-trajectory
rocket. Both of these were guided by autopilots. The operators determined
the location of the target with regard to the place of launching,
estimated the wind drift, computed the required settings and then
applied these settings before the missile was launched. The operator
had no control over the flight of the missile after it was launched
and the missile did not receive any information, intelligence, or
guidance from the target. The accuracy of its fall upon the target
depended upon the accuracy with which the autopilot was constructed,
the accuracy of its setting, and the computation of wind drift by
the operator, although the latter factor was not as important in
the case of the V-2 missile as it was in the case of the V-1. The
only electronic feature was the operation of the autopilot, assuming
that it was not of the hydraulic type.
The next step in
the development of guided missiles was to use an autopilot but control
it remotely by the exercise of the judgment of a human pilot. The
human pilot had to keep both the missile and the target under observation
constantly and exercise his remote control by means of radio. During
the night or during foggy weather, this method did not work, and
even during daylight hours, under conditions of maximum visibility,
the anti-aircraft fire of the enemy and the interception of enemy
fighter airplanes reduced its effectiveness.
some success with radio-controlled guided missiles under the observation
of the remote pilot, the next step was to install a television transmitter
in the missile so that it could "see" the target, that is, it would
transmit its reactions to the emission and reflection of light from
the target, and thus enable the human pilot to direct its flight
by radio. Obviously, if the emission and reflection of light from
the target was weak, or if there were light rays from objects other
than the target, the accuracy was greatly lowered. This limited
the effectiveness of this method so much that the scientists turned
their attention to the use of radar.
In theory, targets
which give good radar reflections can be attacked regardless of
the visibility, thus overcoming the objection to the use of television
repeat-back information, and enabling the remote human pilot who
has the necessary. information regarding the range and direction
of the target to direct the guided missile on an accurate flight
to the target. However, if the target does not emit or reflect radar
signals, this method fails.
Another theory is that if the
remote human pilot knows the exact location of the target on a map,
he can track the flight of the missile by radar, plot its course
on the map, and then direct its course by radio so that it will
dive at the proper moment and hit the target.
A third theory
is that a radar beam may be directed along the path which the missile
is to follow. In this case, the missile must carry equipment which
will enable it to follow the radar beam. The advantage to this theory
is that if the target, such as a ship, an airplane, or any other
movable enemy object, changes its position, the radar beam may be
directed to the new course of the target and the missile will still
strike the target. Again, a human pilot must be on watch from the
moment of launching until the fall of the missile on the target.
These theories based on the use of electronic equipment
have been seriously considered by scientists for several nations,
but the necessity for controlling the missile by the exercise of
the judgment of a human pilot has not been as attractive as the
possibility of developing a missile which would automatically seek
Target-seeking guided missiles are sometimes
called homing missiles, but this term suggests the return of the
missile to its launching point, hence it is better to refer to them
as "target seeking."
Although electronic engineers play
a vital part in the development of guided missiles, they are broad
enough in their thinking to consider all physical laws in searching
for new methods. For example, they have discussed the possibility
of guiding missiles to their targets by means of the emission or
reflection of sound at the target. This depends upon the intensity
and direction of the sound at the target. Battlefield noises, and
even the ordinary industrial noises, reduce the effectiveness of
this method, but the problem becomes hopeless of solution when it
is realized that the missile itself produces noise, both internally
and externally, as it travels through the air.
of light from flares or searchlights, contrasts between light and
Dark areas, and similar light con-ditions at the target could be
used as sources of guidance for target-seeking missiles but here
again we would be faced with the obstacle of varying con-ditions
The emission of heat rays from the
smokestacks of ships, industrial plants, and similar targets, may
be used as a source of guidance, but this method is limited because
of varying weather conditions, and fluctuations in the generation
of heat at the target. Heat and light are both within the electromagnetic
spectrum, hence they emit or reflect electromagnetic radiation,
but they do not do either as well for our purposes as radar, which
is reliable night or day, regardless of weather.
application of radar to the control of guided missiles, two entirely
different systems have been tried. In .
one, the missile contained
only a receiver. The transmitter was on the "mother" airplane and
emitted short pulses of high intensity. Mechanisms within the missile
which kept it pointed toward the target were activated from the
In the other type of radar-controlled
missile, the missile is set for a particular target, released, and
then it automatically follows every movement of the target until
it strikes, leaving the mother airplane entirely free to go on another
The principle underlying the operation of this
fully automatic target-seeking missile resembles that used by a
live bat which gives out short pulses of sound and is guided by
echoes from the sound, thus avoiding collisions in the dark. The
missile emits pulsed microwave electromagnetic radiations and is
guided by the radar echoes from the target. Since the missile can
follow every movement of the target, it is possible to say that
the radar robot pilot inside the missile can "see" the target under
all conditions of visibility.
A missile of this type can
be carried under the wing or fuselage of an airplane and released
several miles from the target. The usual procedure is to first locate
the target by means of the standard search radar carried by the
airplane. The airplane is then flown toward the target and the radar
transmitter and receiver in the missile are aimed in the same direction.
Target information received and transmitted from the radar in the
missile is displayed on a special indicator in the airplane and
controlled by the operator. As soon as the radar equipment can be
manually adjusted to the prevailing conditions, it is switched to
automatic tracking and the missile is released.
the target are continuously detected by the radar receiver installed
in the missile. The flight control units receive corrective signals
from the output for the purpose of guiding the missile toward the
The advantages of this fully automatic, target-seeking
missile are as follows: (1) The self-guiding feature enables the
launching airplane to go on another mission and maneuver as desired:
(2) The self-guiding or homing feature increases the accuracy: (3)
Heavily armed targets outside the anti-aircraft range may be accurately
G. Pierce of Los Angeles, electronics engineer for the General Electric
Company. and B. L. Dorman. chief test engineer of Aerojet, view
the television installation in the test pit prior to televising
the test of firing high thrust rocket motors at Aerojet Proving
Grounds. Developed by Aerojet engineers, this method of televising
rocket motor tests was successfully demonstrated with the cooperation
of engineers of General Electric Company who furnished the television
equipment. This method, used for the first time anywhere, provides
safety from the hazard area to observers located in a remote room
who may view the tests with added advantages of better lighting
and close-ups never before provided.
The system just
described was installed in the "BAT," the first fully automatic
guided missile successfully used in combat by any nation. It was
one of several guided missiles developed by the National Bureau
of Standards under the sponsorship of the Bureau of Ordnance of
the Navy Department and has led to further research on advanced
Statements in this article are the personal opinions
of the author. They are not to be construed as necessarily reflecting
the official opinions of the Navy Department or the naval service