I was cleaning out some old magazines today, and I found the following article on the history of the Aircraft Radio Corporation. This appeared in the June 1984 issue of AOPA PILOT, and was written by Gordon Eliot White of Washington D.C. Mr. White donated thousands of ARC collectibles to the Smithsonian. Tom n5off The partial text follows . . . ============================================================ . . . . .in 1935 Drake began designing a new series of military aircraft radios. They were to meet his ideas of the equipment the Army needed, setting new standards of stability and reliability, and were to contain multiple channels. The model B and the SCR-183 had used a rack full of plug-in coils to change frequency bands. Their dials were marked from 0 to 100, and to tune in a particular frequency, the pilot had to refer to a calibration chart. The new equipment would be marked directly in kilocycles and megacycles. Drake's design, which used superhetrodyne techniques, consisted of miniaturized receivers half the size of the SCR-183. The designers brilliantly solved stability problems by developing a temperature compensated tuning circuit. The mathematical basis of "tracking" the local oscillator and the incoming signal over the tuned band was worked out by engineer Paul O. Farnham so that the shape of the mechanical capacitor provided the offset required. Various components in the receivers were designed as easily replaceable items, before either of the terms "miniaturized" and "modular" were coined. These so call "channel" sets were first built in the ARC labs in 1935. Known as Type K within the company, they were far in advance of other equipment then available, but they did not meet the letter of official Army requirements. Developments continued at Boonton, N.J. for three years before the Navy finally ordered a prototype Type K system; the Navy adopted the design as its GT/RBD set in 1940. However, the Army Signal Corps was engaged in a conflict with the Air Corps over aircraft radio specifications and insisted on developing a crystal controlled set. Bendix Radio, a long time builder of air carrier equipment, developed the set the Signal Corps wanted, the SCR-240-but it was the size of a footlocker, and the airmen rejected it. In 1940, Roosevelt called for a 50,000 airplane air force to meet the threat of war in Europe. The Army asked Bendix to copy the GT/RBD, but in August of 1940, it abandoned that effort and adopted the ARC set in toto as SCR-274-N. The N stood for "Navy," the only time the Army would so designate an aircraft radio system as having originated with its sister service. Anyone who flew during W.W.II can recall the SCR-274-N, the various Navy versions, and the final joint nomenclature set, AN/ARC-5. These were ubiquitous in military aircraft, and the low frequency range receiver, R-23 (BC-453) remained in service until recently, particularly in aircraft that flew overseas where the Adcock ranges were still used. Western Electric, Colonial Radio and Stromberg-Carlson helped ARC produce nearly 1.4 million receivers, transmitters, modulators and other individual items as the basic system, known generically as the "command sets." Crystal control, though accepted in commercial flying, was rejected early in W.W.II because of the critical shortage of radio-grade quartz. Eventually, sufficient crystals did become available, and multichannel crystal controlled equipment was designed. British development of VHF radio was another wartime advance, and the UHF units were developed for the AN/ARC-5 system. During the crystal-tunable debate, ARC designed a technically elegant, tunable VHF receiver and a less satisfactory non-crystal transmitter in the Type K modules. In 1945, the Civil Aeronautics Administration used the receiver section as the basis for its VHF omnirange receiver. Western Electric, Bendix, General Electric and RCA had built commercial radio equipment before the war, along with Wilcox, Sperry, Harvey-Wells, Northern Radio, and others. Little of it, however, was adapted to private aircraft except for some fairly simple GE and RCA designs. Because ARC's President Lewis Hull had rejected the Army's and Navy's vast expansion plans of 1940, at the end of W.W.II the company was neither saddled with an enormous plant to convert to peacetime work nor faced with an apparent demand that it seeks new markets. ARC planned to continue doing what it had done brilliantly in the late 1930's-design and produce small quantities of top-quality, state-of-the-art aircraft radio equipment. Immediately after the was, ARC engineers worked with the Civil Aeronautics Administration developing a receiving system to operate with the new omnirange navigation system. The receiver was an update of the 1944 R-112/ARC-5 unit, with the frequency coverage slightly adjusted. ARC very quickly converted the beacon and broadcast band SCR-274-N and AN/ARC-5 receivers into civilian models with little more than a different paint color (gray) and a lighter and simpler rack and joint system. The wartime transmitters in the HF bands were only briefly produced as civilian items-too many thousands of surplus units were already available on the market-but ARC designed a small, much more compact VHF transmitter that worked with the updated receivers. ARC's former military market, however, never again materialized, and Collins Radio and Bendix took the airline sales. Business aircraft constituted the market that ARC needed, but when the brief postwar private aircraft bubble collapsed in 1947, ARC lost money for the first time in a dozen years. The Korean War, which began in 1950, rescued the people up in Rockaway Valley. The Army began to create its own air force of small twin-engine and single-engine airplanes and helicopters for which the ARC equipment was ideal; even if it was based on 1936 design, the equipment was nicely updated and still quite reliable. Some oddball units came of Korea, including a "transverter" that converted VHF signals in the 118-148 Mhz band into the 220 Mhz frequency area of the Air Force AN/ARC-27 transceiver. Since the ARC-27 and its sister equipment were designed for the B-47 bombers and heavy Air Force fighters and could not be accommodated in helicopters, ARC threw together the transverter, known as the AN/ARC-60, to enable them to use and existing low band VHF system. The company went into electronic test equipment and auto pilots, course directors and other expensive navigation gear aimed at the military. Nevertheless, when the Korean War ended, ARC once again faced economic difficulties. Lacking the size and reserves of larger companies, it could not amortize the cost of its research and production facilities over enough sets to remain competitive. Its prices were so high that the General Accounting Office was called into audit costs on at least one government contract. By the 1950's a number of ARC engineers who had done much of the W.W.II work were leaving to set up their own companies or join others-Stuart Ballantine and Atherton Noyes were prime examples, but there were a dozen others-and ARC was closer to hanging on the ropes. ARC worked with Laurence and David Rockefeller's Airborne Instruments Laboratory on Long Island, developing a classified airborne radar countermeasures set. The Rockefellers bought up a controlling interest in ARC and sought to merge the company into an electronics conglomerate, reminiscent of the way RCA had been formed 20 years earlier with RFL's patents. A flirtation with Litton Industries left some former ARC stockholders wealthy and others frozen out. Finally, in 1959 Hull negotiated a stock swap that made ARC a wholly owned subsidiary of Cessna Aircraft. Cessna was seeking an in-house source of radio equipment built to meet a price, that was unlike the designs the old hands at Rockaway Valley had built. (Predictably, discontent, grumbling and rifts affected the staffs). At the time, the transistor was poised to push the vacuum tube out of the aircraft electronics, the most revolutionary change in technology since Lee de Forest invented the vacuum triode. The equipment ARC built to Cessna's requirements bore no relationship to the W.W.II sets. It did not measure up to the cost-is-no-consideration military designs. Transistors provided smaller transmitters and receivers but not necessarily better performance. Engineers who were at ARC at the time say that the rotary switches were cheaper, the crystals were cheaper, the designs were cheaper. Within the company the older hands carried on with military work, but a number of ARC bids on later government failed to yield any business, because ARC costs were out of line or because ARC could not afford the old ploy of "buying in" on a contract cheaply and then making its profit on follow-ons or cost overruns. There were attempts at other work under Cessna. Hydraulic experts from Wichita proposed a line of systems to automate farm equipment such as tractors, and backhoes, but a cash shortage killed the project. Paul B. King Jr. engineered the first successful frequency synthesizer, following classified work by H.F. Hastings and Robert Stone at the Naval Research Laboratory, but secrecy restraints prevented ARC from commercially exploiting King's breakthrough before others had reached the market. Under Cessna, ARC designed a few military systems that were well built as ever, though none of them became as important as the W.W.II sets. There were the AN/ARC-39, a prototype Air Force liaison set; the type 210 VHF transceiver, a subminiature ADF for Coast Guard helicopters; and the ARN-30D, a beautiful little 190 channel omni receiver in a package that still fit the old AN/ARC-5 racks. It was the end of the line for the command sets and the end of the line for ARC. The design, several times updated, had survived for nearly 30 years, but the reputation it made for ARC finally was obliterated. By the end of the 1970's, death and retirement had taken virtually all of the original engineers. When the aircraft depression of the 1980's struck Cessna, ARC was expendable: in December 1983, Cessna sold the line to Sperry. The laboratories of Boonton have been closed, and the equipment and fixtures auctioned. The production line was still running in April (1984) but all work was scheduled to cease by year end. Manufacture of the remaining ARC line is to be shifted to Sperry's Phoenix facility. END ========================================================== Just a note, I was able to get an ARC manual from Sperry several years ago. They were supporting the old equipment. N5OFF