[ARC5] BC-348 in a B-36

[Scott Johnson]

There are two drums visible, but they are RADAR related, modulators, I
believe for the gun laying.  The RT-128 mounts sideways, and is MUCH larger.
I do see the 6 turbo wastegate servo amps, of which I possess a sample.
Very interesting output tube, a twin triode packaged like an 829B.  These
were also used on the B-50 and KC-97.  I wonder when the C-DAT oscillator
mod was done, I have seen it in most postwar USAF and USN aircraft that
carried the ART-13.  I have also seen a version, usually branded with the
airline name, on civil airliners carrying the ART-13.  I wonder how many
airliners used the ART-13?  The 18S-1/4 seems to be a crystal controlled
radio built with surplus ART-13 and ARR-15 parts (or at least it borrowed
the designs).

Scott V. Johnson W7SVJ
5111 E. Sharon Dr.
Scottsdale, AZ 85254-3636
H (602) 953-5779
C (480) 550-2358
scottjohnson1 at cox.net
scott.johnson at ieee.org

-----Original Message-----
From: arc5-bounces at mailman.qth.net <arc5-bounces at mailman.qth.net> On Behalf
Of Mike Morrow
Sent: Wednesday, January 1, 2020 1:01 AM
To: arc5 at mailman.qth.net
Subject: Re: [ARC5] BC-348 in a B-36

$cott wrote:

> Note that it has an ARC-21 as well as the ART-13/BC-348.

Yes, there are lots of interesting units visible.  Both the 140-lbm
RT-128A/ARC-21 pressurized drum and its C-451/ARC-21 control are still in
place.  Apparently this installation did not include the R-224/ARR-36
auxiliary receiver often used with the AN/ARC-21.  Controls are visible for
the AN/APX-6 IFF and AN/ARC-27 UHF command set.  Elsewhere there must be an
AN/ARC-3 or -36 or -49 VHF command set and a couple of AN/ARN-6 ADFs.

The AN/ARC-8 appears to be using a BC-348-R (AN/ARR-11) and I'm sure its in
the proper location.  The transmitter is a T-412/ART-13B converted from a
T-47/ART-13 (Note the "LOW FREQUENCY EXTENDED RANGE" switch below the
instruction plate that permits crystal-control operation down to just above
1600 kHz).  The lack of vernier scale on VFO dial B shows it was not a
T-47A/ART-13.  All of the frequencies are shown on the setting card as set
by VFO, so the CDA-T unit's 20 MF/HF crystal-controlled frequencies are
unused.  VFO frequencies include the common 3043.5 kHz that replaced 3105
kHz in the early 1950s (channel 1) and 8364.0 kHz emergency/survival/rescue
frequency (channel 10).  Without the VFO dial B vernier scale it would have
been challenging to accurately set the several fractional-kHz VFO
frequencies shown on the setting card.  Card info for frequencies below 600
kHz shows only a crystal-controlled 500 kHz CDA-T channel 1 assignment, yet
there seems to be no place for t  he large CU-32/ART-13A LF/MF PA tank coil
unit.  I do not see the AN/ARC-8 MONITOR-NORMAL switch but it's got to be
somewhere.

Even though the space is missing a lot of equipment and systems, it's still
fascinating.  The Jimmy Stewart 1955 film "Strategic Air Command" shows an
earlier-era B-36 with two AN/ARC-8 installations and no AN/ARC-21.

Mike / KK5F
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