[MRCA] ARC Equipment in general - was: A.R.C. Type 21 (AN/ARN-59) ... somewhat longwinded

[Michael Tauson]

-----Original Message-----
From: mrca-bounces at mailman.qth.net [mailto:mrca-bounces at mailman.qth.net] On
Behalf Of D. Platt
> Both the 21-A ADF and the ARC-210 VHF comm sets were 
> top dog for the corporate size aircraft in the 60's and for a number of 
> years later.  I still have one '210 system with a Gables head for it.   

I have an original equipment FES-1240 pulled from a 1960 Cessna 310 in
anticipation of the allowable equipment rules change that took effect on 1
Jan 1997.  (This was to make provisions for the coming 25KC channel
spacing.)  It includes two Type 210s, two Type 15s - one with an R-31 Glide
Slope and the other having an IN-14 indicator which has inputs for the CD-2
Course Director - an R-33 3-light marker beacon Rx, a Type 21A and an F-13
audio amp, all controlled by a C-77 control head.  The original design used
one Type 210 and a T-25 which was to be used with the #2 Type 15 but mine
was upgraded somewhere along the line.  I also have a second Type 21A from
the same aircraft but no control head for it.  While I don't have a second
IN-12 to go with it, a Bendix dual ADF head did arrive which I'm told worked
with the Type 21A equipment in place of an IN-13 dual ADF head.  Something I
don't have in an installation manual since the wiring isn't quite like that
used for individual units.  Finding a manual on the FES-1240 or C-77 has
proven futile thus far but hope springs infernal or some such thing.  (What
was it Einstein said about doing the same thing over and over hoping for
different results? :-) )

The original owner told me that the airplane had one each CD-1 and CD-2
course directors but they were changed out earlier and he didn't have them.
I'd like to find a set as well as the 2nd Type 21 control head to complete
the installation as it was in that airplane.  

I'm told but have not confirmed that this same system was installed in at
least a few of the original U-3As purchased by the Air Force.  

Speaking of ARC and postwar military installations, I have a C-40
replacement head made in 1960 intended for Dzus rail mounting.  The C-40 is
a peculiar duck in that it is intended for the old "standard" 3 Rx, 2 Tx
installation common to WW II aircraft but using a mix of AN/ARC-5 and Type
12 equipment.  The AN/ARC-5 components are the R-26, T-19 or T-20, T-23
(although one can hope it had been upgraded to a T-126) and MD-7.  The Type
12 components are the R-11 and R-19.  There is provision for an FM set which
would have likely been something like a BC-1335 in the original.
Considering the date of this head, I believe a fair assumption would be that
the PTT and audio went to an AN/ARC-44 & AN/ARC-45 pair instead - or at
least the mic & PTT did.  I haven't yet thought about how an S-474 audio
switch would figure into such an installation.  (Acquiring manuals on the
AN/ARC-44 & -45 plus whatever's needed for the S-474 might help.)  

There were 10 and 20 channel versions of the T-11B and T-13A made.  The 10
channel version of the T-11 was the T-21 and the 20 channel one was the
T-22.  The 10 channel T-13 was the T-23 and the 20 channel one was the T-20.
(Note the consistent numbering system ... consistent for ARC, that is. :-) )
The T-21 and T-23 essentially integrated the 10 channel upgrade kits into
the design and were built on the same size chassis.  The T-22 and T-20 were
modified slightly to allow for the additional 10 channels.  All of them
require the channels be in a 2 MC range which implies the T-22 and T-20
could be channeled on a 100 KC spacing which was still fairly common at that
time.  

Thus far, I have not found control heads that take advantage of the T-20 &
T-22 so I don't know how widespread their use was.  OTOH, many, if not all,
of the Dzus rail mounted control heads could handle 16 channels (one either
FM or blank) which means they could control up to three T-11s and/or T-13s
or a mix of one each T-21 or T-23 with a T-11 or T-13.  The space and weight
savings wouldn't mean a lot in twin engine aircraft but in something like an
L-19 or a helicopter, it would.  

> I will always have a fond place for A.R.C. and their stuff.  Its a shame
Cessna turned them 
> into an el-cheapo company.  I'm sure that hastened their demise.

ARC was an exceptional company.  Even in the 1930s when they got their early
start with military contracts (SCR-A*-183 and GF/RU), they were a very small
fish in a very large shark-infested ocean yet managed to gain contracts the
others didn't.  How?  They designed and built darned good equipment that
outperformed what everyone else had.  They did one thing and did it well;
they made HF command sets.  Period.  Their brief foray into VHF would likely
have been added to the line had quartz not become more available for
additional crystal controlled equipment like that which WE and Bendix made.
Even so, the education they gained proved valuable for the postwar
equipment.  

During the war, ARC & Stromberg Carlson handled the Navy contracts while WE
built SCR-274-Ns for the AAF.  It has been claimed that WE "improved" the
sets by using cost and time saving measures in their construction.  Nothing
could be further from the truth.  They took an excellent design and
"Cessna-ized" it to keep up with the AAF's loss rate in Europe.  On the
other hand, the Navy & Marine Corps didn't have the high demands the AAF did
either in aircraft available or in loss rates so ARC & Stromberg Carlson
were able to retain the original design including the handmade and adjusted
mica capacitors used in the transmitters.  ARA/ATA equipment and the later
AN/ARC-5 equipment was superior to the SCR-274-N in quality if for no other
reason that adherence to the original design specifications.

It should be kept in mind that the AAF was losing large number of airplanes
(specifically bombers) on pretty much a daily basis toward the beginning of
the US's participation in the war and, while the SCR-522 was used to
communicate with British facilities, the SCR-274-N was still carried aboard
nearly every bomber flown.  (There is at least one photograph of a British
tower with an SCR-274-N in clear evidence which indicates they were still in
use even for ground communications.)  The loss rate went down as German air
defense capabilities were reduced but the cheapened radios continued to be
produced simply because they had the facilities in place and returning to
the original design would have been difficult and costly at best. There's no
denying the trend was toward VHF but looking at production numbers through
the war, it wasn't until 1944 that the SCR-522s produced clearly outnumbered
the SCR-274-N equipment.  

ARC learned a great number of things during the war which it applied to the
Type 12 equipment.  The first offering, the Type 11 which consisted of the
T-11 and R-11, came out in 1946 and wasn't designed in a vacuum.  The T-11
and later T-13 don't have an obvious path back to the T-89 & T-90/ARC-5 but
lessons learned don't always show that clearly.  The R-11, on the other
hand, was an obvious derivative of the 190-520 KC command receivers
redesigned strictly for remote control and with provision for the T-11
added.  While the Type 11 was available in July 1946, the R-15 108-135 MC
receiver didn't become available until 1947 with the military versions - the
T-13 and R-19 - appearing about the same time.  

The R-15 begat the Type 15 which included a modified version of the receiver
designated as the R-13 and the B-10 converter & F-10 filter for VAR use (VAR
is VOR plus audio to help those used to flying range convert.  The blue &
yellow segments on the older VOR/ILS heads are a reflection of this as
well.) with provisions for a glide slope receiver that ARC didn't produce at
the time.  The F-10 was later dropped and the B-10 replaced by the B-13 for
VOR/localizer use with the R-34 coming even later.  In the meantime, though,
the R-15 was dropped as being redundant. 

By the time Cessna bought out ARC, the line had been modernized to include
the Type 15E & F; the TV-10 (military only); the Type 210; the rack mounted
R-31, R-33 and T-25; the Type 21A; the CD-1 and CD-2 Course Directors; an
assortment of audio amplifiers and associated test equipment, all built to
ARC's well known high standards and all swept aside with Cessna's "cheaper
is better" vision in 1963.  While Cessna managed to recover and build decent
equipment later, the damage had been done and ARC's reputation had been
destroyed by early management mistakes (to put it mildly) never to be
recovered.

The original T-11, T-13 and a few other pieces continued to be built to
fulfill military contracts plus the AN/ARN-72 was offered however I have no
reference as to what it was or how well it was received.  

Sorry to be so long winded (actually, I'm not ;-) ) but ARC is a favored
subject with me.  I don't know anywhere near what Gordon White, Mike Hanz or
Dave Stinson do but I don't have a life so have the opportunity to type a
lot more than they do.  :-D

Best regards,
 
Michael, WH7HG, A&P 1803851 Ph: 1-866-733-0218
Note to self: Need more henchmen, good ones this time.  Also, start
auditions for new female lab assistant.
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