Pilotless Plane Run by Radio
May 1946 Radio News

May 1946 Radio News [Table of Contents] Wax nostalgic about and learn from the history of early electronics. See articles from Radio & Television News, published 1919-1959. All copyrights hereby acknowledged.

News reports are full of features about the wave of radio controlled (R/C) "drones" terrorizing citizens with their often inexperienced pilots navigating their camera-laden craft to peer into bedroom windows, obtain "birds-eye" views of sporting events, and to be a general pain in the posterior to people trying to enjoy their right to privacy and safety (except, of course, unless it is the Government choosing to violate them). Incredible advances in radio, navigation, and sensor systems has facilitated a wide variety of very affordable multirotor (the correct term, not "drone") aircraft that can literally fly themselves. For under $500 you can buy a GPS-guided multirotor that can be programmed to fly to one or more waypoints and return to the launch location, with range and flight duration limited only by battery capacity. Gimbaled, remotely steerable cameras can snap photos or record video and either store it onboard for later retrieval or wirelessly transmit the images back to the operator. Platform stabilization is provided by ultra-miniature, ultra-lightweight orientation and rate gyros with precision and accuracy that could not have been realized even two decades ago. Intelligent software practically negates the need for an operator to do anything other than point the craft where he/she wants it to go. Compare this to what was considered ground-breaking remotely piloted aircraft technology in 1946.

Pilotless Plane Run by Radio

By S. R. Winters

The successful operation of aircraft by remote radio control has been proven practical by the A.T.S.C.

Transforming a 20-year-old vision into an actuality, a pilotless airplane is operated by a combination of factors involving the use of radio and television. The jet-propelled plane, a P-59 Airacomet, is remotely controlled either from a portable ground radio station, mounted on a truck, or from a "flying radio station" in another airplane which "mothers" the robot craft.

"Telemetering," a comparatively new term as applied to radio, and only recently recognized officially by the Federal Communications Commission, means that electronic apparatus installed on the pilotless flying craft transmits to the ground radio station visual images of the vibrations, accelerations, structural leads and strains, and similar stresses encountered by the robot plane. This new telemetering apparatus, designed by Princeton University, is concentrated in the pilotless plane and ground radio station, the "mother" plane being reserved for the exclusive function of controlling the "orphan" craft which flies without any person aboard. The process of determining structural strains and stresses, as well as other data from the pilotless plane, involves the use of resistance units in measuring the plane's performance electronically. Such information is fed, in sequence, to the electronic transmitter at a rate of 1100 cycles per second. This data is transmitted to the ground radio station for reception by a radio receiver that unscrambles the jargon of combined signals and then "siphons" them into separate. receiver channels for graphic recording or visual observation, or both, on a many-channeled oscillograph.

The television equipment on the pilotless plane, manufactured by the Radio Corporation of America, serves a twofold purpose. One unit visualizes the instrument panel on the robot airplane, thus televising the behavior of the instruments during the plane's flight, and this information is relayed to the operator of the ground radio station. The second piece of television apparatus, installed in the cabin of the plane without a human pilot, actually scans the horizon as it would be seen if an honest-to-goodness pilot were flying the machine and this vision of the horizon as viewed by the "robot" is relayed to the operator of radio equipment in the motor truck.

This experimental aircraft, joint brain-child of the Bell Aircraft Corporation and the Air Technical Service Command, Wright Field, Dayton, Ohio, is a preview of an imminent period of flight of commercial airplanes through the combined factors of radio and television. More than a year ago this writer forecast the imminence of the "all electronic airplane" - a craft functioning solely by "electronic fingers" rather than by the hands of a human pilot. Although the Bell Aircraft Corporation is using this experimental jet-propelled plane as a sort of "flying research laboratory" in assembling data that might influence the flight behavior of a plane, the company believes that remote control of aircraft by radio is impending, both from a commercial and military viewpoint. Furthermore, by use of this robot plane the risks of sacrificing human pilots in hazardous flights at sonic and supersonic speeds are averted.

The successful flights of this radio-operated plane - since October, 1944, but until recently among the war-pigeoned secrets - are attributed largely to a new concept of the auto-pilot - described as the "rate" auto-pilot by Robert M. Stanley, chief engineer of the Bell Aircraft Corporation. This novel gadget, automatic in performance, assures control of a plane where the orthodox autopilot leaves off - and it can function dependably when the craft is approaching a diving altitude.

Turbo jet-powered planes were chosen for the initial tests with pilotless, radio-operated flying machines for several "down-to-earth" reasons, namely, the absence of torque and vibration; their stability even at the speed of sound; their efficiency in the stratosphere or other high altitudes; and the stability they demonstrate when landing by means of tricycle landing gear.

More about the new version of the autopilot - the "rate" autopilot - which receives the lion's share of credit in realizing the aeronautical engineer's dream of controlling aircraft solely through the means of radio and television. Instead of the standard autopilot, controlled by a gyroscope which spins about its vertical axis and is therefore subject to "spilling" in violent maneuvers, the new type of autopilot makes use of two rate-of-turn gyro instruments. One of these is so arranged that the gyroscope's spin-axis is vertical as a means of affording a way of sensing a change of pitch. The second gyro device is rotated so as to place the gyroscope fore and aft, thus providing a method for determining the rate of roll.

Then, these two sensing gadgets - the "rate" and "displacement" auto-pilots-are coupled in an electrical bridge, with their functions being interchangeable. The "displacement" or orthodox autopilot is answerable for maneuvers involving less than plus-or-minus 30 degrees change in pitch or plus-or-minus 45 degrees in roll. The new version of autopilot - the "rate" mechanical pilot with its spill-proof gyroscope, is answerable for any other maneuvers to which an airplane may be subjected. The "flying radio laboratory," as well as the ground radio station, has a switch, handy on the instrument panel, which permits of easy selection of the two autopilots. Simultaneously, either or both of these mechanical pilots can be governed from both air and ground radio stations,

A diminutive "joy" stick, functioning like the conventional control stick on a standard airplane, is mounted on the usual stick in the "mother" plane and another pigmy stick, a duplicate, appears on the ground radio operator's chair. This small stick is secured to a platform built on top of the radio-equipped motor truck. The movements of these midget sticks are comparable to those of the conventional "joy" stick. Moved forward, for example, the miniature stick prompts the impulse that lowers the airplane's elevators, causing the radio-controlled plane to dive; moved backward, the undersized stick prompts a climb, and to the right or left, a turn of the airplane in either direction.

The throttle, flaps, landing gear, brakes, etc., of the radio-operated plane are actuated by the usual servo motors, deriving their electrical energy from circuits controlled by the radio receiver. Thus, by coordinating these controls, the radio operators of the flight or ground stations can put the robot through such actions as warm-up, taxiing, take-off, climb, level flight, banks or turns, dives and loops.

The operation of this radio or electronic airplane is dependent upon novel and heretofore untried apparatus, with special and secret radio parts, designed especially for Army Air Forces' Technical Service Command, This radio equipment is as vital to the functioning of the airplane television and telemetering equipment as are the heart and lungs in the functioning of the human body. The incorporation of high-frequency radio apparatus for voice communication is optional rather than a requirement, we are told.

Posted May 11, 2022
(updated from original post on 3/5/2015)