Saga of the OQ-2A Drone
1971 American Aircraft Modeler
visitor John H. requested this article on the OQ-2A drone from
the March 1971 edition of AAM. The OQ-2A was produced by the Radioplane
Company, of California at the beginning of World War II.
Reginald Denny, a famous actor of the time and owner of the
company, was an avid radio-control flyer. Rudder and elevator control
was provided via remote-controlled electric servomechanisms. Norma
Jeane Mortenson, aka Marilyn Monroe, worked on building these planes
in the Radioplane Company's shop.
Saga of the OQ-2A Drone
Thousands of these small radio-controlled planes were built
for the Armed Services by a California manufacturer.
On the dry lakes of California's Mojave Desert, Northrop-Ventura
(then known as Radioplane Company) began, in June 1941, prototype
tests on a target drone with a twelve-foot wingspan. By 1945, the
firm was producing forty of these small radio-controlled planes
per day for the Armed Services.
The OQ-2A was catapult-launched, but it had landing gear which
primarily served to cushion the shock of the drone's landing
Before Dee Bee and Lanier, there was a ready-to-fly radio-control
Strut-supported wings have symmetrical airfoil so that they
are interchangeable, not aerobatic.
Earlier versions had a single propeller and some thrust offset.
Note equipment locations.
Simultaneous-firing 6-hp twin-cylinder engine drives spur-geared
Airframe and engine specifications.
Primarily, these drones
were used to train antiaircraft ground defense units which were
using sub-caliber automatic weapons up to and including 40 mm cannons.
Flying at a top speed of 88 mph, the small radio-controlled drone
had relatively the same size and speed characteristics at 200-yards
range as did a normal-sized World War II fighter plane at 500 yards
distance. The rugged little plane duplicated actual attack conditions
and was easily maneuvered through practically all flight attitudes
over any type of terrain.
Incorporated in the drone was
a 24-foot parachute, which could be released either by the transmitter
operator or automatically when hits were scored on the airborne
radio unit. This permitted salvage of the target and provided verification
of the gunnery crew's marksmanship. The target also could be, and
often was, landed by remote control "dead stick" when sufficient
landing area was available.
Although the target drone was
designed, developed, and manufactured by Northrop-Ventura (Radioplane
Co.), the Frankfort Sailplane Co. (Joliet, Ill.) also was awarded
contracts to produce the bird for the armed services. Its radio
transmitting equipment was manufactured for Northrop-Ventura by
the Doolittle Radio Co. (Chicago, Ill.), the radio receiving equipment
by Bendix Aviation (North Hollywood, Calif.), and the servo unit
by Hansen Mfg. Co. (Princeton, Ind.). The catapult unit was supplied
by Montpelier Mfg. Co. (Montpelier, O.).
One of the most
popular of the family of drones produced by Northrop Ventura was
the OQ-2A (U.S. Navy Model TDD-1) radio-controlled target. The vehicle
was powered by a two-cylinder air-cooled engine which developed
6 hp at 3800 rpm. The horizontally opposed engine was a two-cycle
simultaneous firing type. Two concentrically shafted contrarotating
propellers pushed the drone to a speed simulating that of actual
The engine incorporated a two-throw type
crankcase supported on three bearings. The rear main bearing was
a bronze sleeve. The forward main, a ball-bearing type, was of sufficient
size to carry both radial loads and front propeller thrust. The
extreme front end of the shaft was supported by a pair of ball bearings
which were inside the aft propeller hub. The bearings, piston and
cylinder walls were lubricated by mixing the lubrication oil with
the fuel. The proportion was eight parts fuel to one part lube oil.
Engines were equipped with a centrifugally-operated spark
advance mechanism, while earlier models had a manually-operated
spark advance control timer.
The fuel system was operated
by pressure developed in the engine crankcase. A small check valve
furnished the 2 psi pressure required to operate the system and
the pressure was transmitted from the crankcase to the fuel tank
by a neoprene hose. Total fuel carried by the drone was 1.8 gal.,
which gave the bird a total of one hour's flight time.
ignition system was a battery-coil-condenser type. An ignition battery
of 6V was sufficient to start the engine and normally had a useful
life of approximately one hour.
Spur gearing provided the
counter-rotating drive for the rear propeller. The drive operated
from a gear mounted on the crankshaft just forward of the front
main bearing. This gear drove two counter-gears, the second of which
meshed with the propeller drive gear mounted on the rear propeller
The hub was guided by the crankshaft on the inside
and supported by a ball bearing on the outside. The front propeller
was driven by the engine crankshaft. The gear train was lubricated
with SAE 70 oil contained within the gear housing.
was launched by a 36-ft. catapult powered by a rubber shock-cord
system. This method permitted operation from small restricted areas,
which often resembled actual combat terrain.
was an extremely rugged structure of welded steel tubing, covered
by doped muslin cloth fabric. The fuselage cross section was triangular.
The larger of two openings along the fuselage top surface provided
for the parachute installation; the rear hatch gave access to the
servo control unit and stabilizer mounts.
Wing on the OQ-2A
target were interchangeable and could be used for either right or
left hand installation. Constructed of spruce, they were fabric-covered
and used two full-depth spars, with the rib in three sections. Each
wing contained twelve ribs. The end ones were solid; lightening
holes in ten inside ribs made for a slight weight reduction. Thin
plywood covered the top and bottom leading edges back to the front
spar. The airfoil utilized was the NACA 23012 section. Each wing
was supported by a single streamlined steel tubing strut. Trim adjustments
were made by means of an adjusting screw where the strut attached
to the wing's lower surface.
The fabric-covered tail surfaces
also were fabricated of steel tubing framework. These surfaces were
flat, since no airfoil section was required for good flight characteristics.
Horizontal and vertical stabilizers were identical and interchangeable.
Conventional elevator and rudder, in keeping with the manufacturer's
design and fabrication methods, were the only means used to control
the target in flight.
Landing gear of the conventional three-point
type had two front shock-mounted landing wheels and a leaf-spring
tail skid. Two tubular front landing struts were provided with rubber
shock cord to withstand landing impact. The shock travel was five
inches in the strut, plus approximately two inches in tire deflation.
(In the photos, the display model has had the shock cord removed
from the landing gear struts, thereby giving the drone a somewhat
The target's basic system of radio-control
was an ultrahigh frequency carrier of 73 megacycles modulated by
five different audio frequencies. Four of the audio frequency tones
were used for the drone's four flight attitudes: right, left, up,
and down. The fifth frequency was used to release the parachute,
which in turn operated a manual shutoff system for the engine. The
fifth frequency was operated by a button-type switch, whereas the
other four frequencies utilized a control stick to simulate normal
Incoming signals were received by a twelve-inch
antenna mast, located just forward of the wing trailing edge on
top of the fuselage. The radio receiver had a super-regenerative
type detector preceded by a tuned RF stage. The audio output of
the receiver was applied to five individual audio channels, each
consisting of a band-pass filter, relay tube and relay. (Like an
RC reed system.)
Power for the radio was provided by the
battery box unit mounted in a channel-type tray in the fuselage.
The unit could be shifted both fore and aft, thereby balancing the
ship for proper flight attitude.
The servo unit was activated
by the receiver, thus providing mechanical action necessary to control
the rudder and elevator. Two 6V motors with reversible fields provided
action to the gear trains which gave the leverage required for flight
control. A single package servo unit was located just forward of
the horizontal stabilizer and was accessible through the fuselage
The 24-foot circular canopy parachute was of standard
design. The recovery system also was provided with a standard-type
pilot parachute. A single cable extended from a D ring and was attached
by a shackle to an apex of four riser cables, which in turn were
fastened to four points on top of the fuselage.
entire target drone was fabric-covered with 80-thread muslin cloth
and was dope treated in two colors. The top of the wings was white,
the rest of the ship was red. This two-color combination provided
a visible means of telling the difference between the top and bottom
of the plane during flight. An interesting fabrication sidelight:
the wing fabric covering was manufactured as a sock, which was later
slipped onto the wing structure and doped.
Much of the testing
of the drone was done on the dry lakes of the Mojave Desert. A stripped-down
Packard automobile sometimes was used as a test platform. The test
plane was mounted on a steel platform structure added to the auto's
front section. As the auto approached the drone's flight speed,
the designers could observe the target's flight characteristics
without fear of actual flight damage.
In operation, the
drones were flown by men from various branches of the services.
They were trained by and under the sponsorship of Northrop-Ventura.
This policy of training Armed Services personnel to fly the various
drones was continued late into the 1950's and early 1960's.
Such were some of the early stages in the beginning of radio-controlled
flight. Of the thousands of OQ-2A drones fabricated, only one is
now known to exist and that one is carefully preserved by the Northrop
The OQ-2A drone was phased out near the end
of World War II. Northrop-Ventura's early pioneering with pilot-less
drones help the firm to develop and produce later birds in vast
quantities - notably the OQ-19 and KD2R5 drones.
Note: "As with many old-line airplane firms, Northrop-Ventura's
past is often clouded with this, that, and other things. One thing
the firm never did care to discuss was the fact that Radioplane
was originally founded by Reginald Denny, the old-time movie actor
and long-time modeler. Once the firm began to move along, his activity
with Radioplane became less and less.
"In the 1950's, radio
equipment was supplied to Radioplane by Babcock Engineering, but
Babcock was sort of a spring-off from the main firm. It was headed
up by the late Ferris Smith, who also was a Vice President of Engineering
at Radioplane. The same type of thing occurred with the servo units
and other equipment too. It became very involved and difficult to
understand. The president of Radioplane, the late Whitney Collins,
became the President of Northrop Corporation when Northrop bought
out Radioplane. The name of the company was then changed to Northrop-
"I also believe that Mr. Fox (Fox Mfg. Co.,
Fort Smith, Ark.) was with the company during its early days, but
I wouldn't swear to it.
"I do know Marilyn Monroe
(the late actress) worked in the wing section during the war. Her
career began with some still photos taken while she was employed
"One strange last fact, I went to junior
high school with Marilyn Monroe, class of 1939. Now I skipper a
West Coast commercial tuna vessel." Jim White
OQ-2A Drone Planes (page 1)
OQ-2A Drone Planes (page 2)
Posted February 16, 2013