Radio age research, manufacturing, communications, broadcasting, television (1941)

TECHNICIAN RECORDS OPERATING DATA FROM THE COMMUNICATIONS UNIT BEING TESTED IN THIS RECENTLY DEVELOPED ALTITUDE CHAMBER. TESTING RADIO "7 Miles Up" Aircraft Radio and Electronic Equipment Seen in Operation in Simple Altitude Jest Chamber Created by RCA Victor's Engineers ANEW amazingly simple alti- tude test chamber for aircraft radio and electronic equipment, in which engineers can now for the first time see the entire apparatus in operation under conditions du- plicating the stratosphere seven miles up, has been developed by the RCA Victor Division of the Radio Corporation of America. This sim- ple chamber, constructed of the transparent nose cone of a bomber, is helping to speed delivery of radio equipment to air services from the Company's Camden plant where two of these new chambers are now in operation. Built of transparent Ple.xiglas, a plastic developed by the Rohm and Haas Company, the chamber is ac- tually the unfinished nose of a fa- mous American bombing plane. Be- cause of the transparent construc- tion, it makes possible the complete testing and inspection of any piece of radio apparatus by several en- gineers at one time and materially speeds test work. This new con- struction has eliminated the diffi- culties found with standard test chambers which are constructed of metal and permit vision only through small portholes. Defects in design, which normal- ly would remain hidden until actual high altitude flights could be made, are now spotted at a glance. An entire complement of test instru- ments and meters may be con- nected to the apparatus under test and plainly viewed by the project engineers. At seven and one-half miles up, many things can happen to aircraft radio and electronic equipment, since apparatus of this type incorporates many delicate mechanisms. Low temi)eratures and pressures bring about changes in these delicate mechanisms which may cause current leakage, dis- abling electrical discharges, known among engineers as "flashovers," and other failures which usually will not occur at normal altitudes. This chamber is cone-shaped, about four feet high and five feet in diameter at its base. It is just less than one-inch thick and capable of withstanding tremendous shocks and pressures. Normally, before as- sembly on its bombing plane, holes are bored for the business ends of machine guns and heavier weapons. In RCA's adaptation into a strato- sphere test chamber, the holes are omitted, thus enabling the engin- eers to make it air tight. An air tight seal is accomplished by fit- ting a heavy platform, arranged for mounting radio apparatus un- der test, with a ring of soft rubber. The test chamber cone is then low- ered until its base re.sts on the rub- ber ring. As the air is withdrawn by a powerful suction pump, the atmospheric pressure on the out- side of the chamber forces it down into the rubber ring and creates a perfect air seal. New Discoveries No one realizes better than the scientist that each of his new discoveries is but a small drop in the ocean of in- finite knowledge. No one ap- I)reciates better than the scientist the unlimited gran- deur and mystery of the Uni- versal Plan. The man who says, "I have faith only in what I can see and understand," is one who has put his mind in a straight- jacket. Our knowledge of man, and of the forces within and above him. is infinitesi- mal compared with our igno- rance. Man does not even un- derstand himself, let alone the universe. David Sarnoff tin an XBC broadcast marking the 20th anni- versary of the "National Radio Pulpit.") \ 32 RADIO AGE