Avionics News June 2013 - 68

feature

T H E H I S T O RY O F

Part 2

AVIONICS
S

S T O R Y

B Y

T H O M A S

I N M A N

ince 1963, avionics has been accelerating through a continuous series of revolutions. As prefaced in last month’s article, the
history of our industry runs deep. But the proud history of avionics since the dawn of the Aircraft Electronics Association’s
founding in 1957, could perhaps be best described in two words: acceleration and revolution.
The avionics industry was in the midst of its first revolution as the AEA was first established. For example, this was evident in the
January 1964 issue of Avionics News, which contained an article describing the technical theory behind bipolar transistors. According
to Thornton E. Benson of Airborne Electronics Inc. in Memphis, Tenn., “Most technicians shudder when a transistor device enters the
shop.” Since transistors were “as modern as rock and roll,” and would “be around for some time,” Benson thought it was a good idea
to tutor technicians about bipolar transistors, in both NPN and PNP form.
Driving home the point was an advertisement in the same issue that promoted the Flite-Tronics replacement for rotary dynamotor
alternators. The model PC-10 would convert 27.5 VDC (volts direct current) to 125 VDC and 13 VAC at 100 Hz with no moving
parts. Switching power supplies were just the start of a transistor revolution. Soon, the vibrating or rotary power supplies for smallaircraft avionics would be a thing of the past.
Dominating the general aviation avionics field at the time were King, Narco and ARC. Narco was leading the pack from medium
twins down to single-engine trainers with its Mark 12. All three manufacturers featured hybrid systems, referring
to the engineers designing the radios with both vacuum tube and transistor technology. All used
transistor switching power supplies to supply B+ voltage to the vacuum tubes, which did
the bulk of the work. All of these radios were crystal synthesized and channelized.
On the communication side, pilots could transmit on any channel selected. As a
EDITOR’S NOTE:
bonus, the channel selector controlled both the transmitter and receiver, which
As part of a year-long celebration
is something we take for granted today.
to commemorate 50 years of publishing
A look inside the popular Narco MK-12A reveals glimpses of the
excellence by Avionics News magazine, this is
the second in a two-part series that explores the
future. Nestled on the navigation side of the unit toward the back is
fascinating history of avionics. This grand history
a resistor pack, which contains several resistors integrated into a
stretches back more than 40 years prior to the Aircraft
single package. In other words, it is an early version of an inteElectronics Association’s founding in 1957. While a
grated circuit. Look closely and discover that the remote power
comprehensive history of such a dynamic subject is
supply/modulator/audio unit wasn’t the only place transistors
challenging within the confines of a magazine, the first
article in last month’s issue noted some of the industry’s
were used.
most important highlights pre-dating the AEA. This month’s
As solid-state components worked their way into avionics
recollection of history outlines the major technological
equipment, engineers began to experiment and discover ways
advances in the industry after the AEA was established. The
to make reality out of possibility. Distance measuring equipauthor, Thomas Inman, is an aviation associate professor in
the School of Transportation Technology at the Pennsylvania
68 avionics news
june 2013
College of Technology in•Williamsport, Penn.

Avionics News June 2013

Table of Contents for the Digital Edition of Avionics News June 2013