[ARC5] 12 V SCR-274N

[David Stinson]

----- Original Message ----- 
From: "Jack Antonio" <scr287 at sbcglobal.net>
Subject: [ARC5] 12 V SCR-274N


> The Army and Navy had 12 and 24V versions of many other
> sets, such as the SCR-187 and -287, SCR-183 and -283, RU-16 and -17 etc.

The conversion of U.S. military aircraft from 12 volt to 24 volt became 
general policy
in the very late 1930s.  You'll find mass production of the 12-volt sets 
ending in
about 1940-41 and mass production of 24 volt sets beginning about that time.
There were lots of 12-volt aircraft still in inventory, and even more with
our Allies.  So you can't set hard dates; these things sort of blended into 
each other,
and some 12 volt sets were built quite late, but when viewed in the "Big 
Picture" light,
12 volt sets were phased out in favor of 24 volters in about 1940-41,
and the newer aircraft that required Command Sets were almost entirely 24 
volts.
The older, 12-volt aircraft already had their sets and needed only spares 
support.
An interesting aside: The RU-16/GF-11 12 volt-radio was built late, but was
primarily intended for use in 12-volt vehicles, not aircraft.
73 Dave S.