[ARC5] Re: [Milsurplus] AM-26/AIC and A.R.C. type connectors

[Michael Tauson]

On Sat, Jul 19, 2008 at 2:53 AM, Mike Hanz <AAF-Radio-1 at aafradio.org> wrote:

> Michael Tauson wrote:

>> The first question is probably the easiest, that being who created the
>> AM-26?  There's no all fired hot reason to ask, I'm just curious.

> Aircraft Radio Laboratory at Wright Field.  See snippet below from the Unsat
> Reports (UR) that I posted on my website:

Ah,cool.  Thanks!  (I read the whole thing and learned a lot about
A.R.C. equipment & WE built A.R.C. designs in the process.)

Any ideas who all built them?

>> The second is a bit more amusing.  I know about the AM-26; ARC-3, -36 and -49; and
>> the ARR-2 but were the A.R.C. type connectors used elsewhere during the war?

> AN/APR-9, ARW-mumble, and some prototypes I've seen - on airborne equipment
> at least..

I know the RT-122/ARW-25 fits one bay of a Type 12 receiver rack (if
one drills holes for the locater pins) but doesn't it have an Amphenol
connector on the front?

(Anyone happen to have any info on that beast - schematics, manuals,
etc?  Same question but on the APR-9)

Mentioning the "ARW-mumble" reminded me of a forgotten (by me)
discussion here or somewhere a few years ago regarding some of the 4
channel + carrier drop bang-bang drone receivers.  I think someone in
that discussion mentioned a few of those receivers that had
A.R.C.-type connectors as well.

> They had sealing issues the Navy couldn't live with unless you used the flex conduit
> backshells (which limited installation flexibility for random installations),

The RCAF fixed this by making their own equivalent control boxes etc
with Amphenol connectors.  I do understand about the leakage issues
though.  Mention of corrosion and other icky stuff has been made more
than once with these connectors.

> and the lack of a keyway made connection in tight spaces difficult.

This was addressed in the postwar connectors.  Too late for wartime
use but they still addressed it.  Even then, the keyways weren't quite
as perfect as they could have been.

> The Amphenol and Cannon designs were vastly superior in operational use, so I'm sure
> no one except ARC shed a tear when their use came to an end.

I wonder if A.R.C. did either.  The war gave them a lot of experience
which resulted in an overhaul of the connector line afterward
including introducing two new shell sizes and gold plating.  I've been
going through some A.R.C. Engineering Notes I have but, thus far, I've
not found anything that indicates any problems with the redesigned
connectors.  This doesn't say there weren't any, just I haven't found
any yet.  On the other hand, the civilian aircraft for which the
postwar equipment was designed weren't getting shot at as a rule,
weren't enduring carrier ops and otherwise enjoyed a more sedate life.

However, even A.R.C. abandoned the A.R.C. type connectors.  The Series
40 (T-25, R-31 & R-33 plus a few other items I can't remember at the
moment) were designed at the end of the pre-Cessna era and fit ARINC
racks with the industry standard connectors rather than using their
own (which meant one could swap out A.R.C. and install Collins instead
- or vice versa) and used entirely different connectors on the control
heads.  I want to say DB-25 but it might be an entirely different
series.  They used several after Cessna started doing their thing and
my "scorecard" isn't up to date yet.

I don't think anyone would argue against the superiority of the
Amphenol or Cannon connectors.  Even now, there's not much that can
match them.

BEst regards,

Micahel, WH7HG