[Milsurplus] Navigation System

[Michael Tauson]

Hi, Mike,

> > Next, what indicator was used with the BC-733
localizer receiver & the ARN-5 glide slope receiver? 

> The indicator was the I-101-* cross-needle display. 
All the ones that I've seen were I-101-C units.  I
know of no connections of the ILS to an autopilot. 
That would be scary...trying to automate the landing
of a WWII-era equipment aircraft.

Good point.  On the other hand, a tired pilot landing
a damaged airplane wouldn't be any sort of picnic
either.  I have no idea how they did it once, let
alone time after time ... but that's subject for
another conversation.

> > The ADF won't be a problem since I'm sure I can
find all the important pieces for an MN-26, BC-433
and/or ARN-6. 

> For WWII-era, you'd have to omit the AN/ARN-6, which
is definitely a post-WWII set.  Oddly enough, the
improved SCR-269 (BC-433) ADF, the AN/ARN-7, well
predates the AN/ARN-6.  

*chuckling* ... Yes, we must be uniform about this.
<G>  I think I’ve seen an ARN-7 or two floating around
so that shouldn't be a real headache.  Were the
control boxes the same as the ones for the SCR-269 or
were they changed too?

> In the JAN system, *usually* the individual
component numbering sequence is a better indication of
precedence than is the system numbering sequence.  

The Collins 18S-4 (for which I need at least a
schematic for now) was also the RT-698/ARC-59 while
the 618S-1 (non-SSB version) which was a later design
was the RT-311/ARC-38.  (The SSB version, for which I
would like to find a control box, was the
RT-594/ARC-38A.)

> Of the many WWII-vintage marker beacon (MB)
receivers, the BC-1333 is likely the best and is
pretty common in new condition.  

All three (BC-341, -357 and -1333) are easy to find,
and I think I can get a BC-1333 still in the box.  NO
mount, though. Does it fit the same as the others?

> The MB indicator used by WWII-era MB receivers was a
simple 28 vdc indicator lamp assembly.  

I presume there was a tag that said something like
"Marker" or some other thing to uniquely identify it. 
OR I hope so at least.  ("Hey, Fred, I've got this
little blinky light on the panel.  You remember what
it's for?" <G>)

> > I'm having a bit of a problem with connectors,
mounts and the like (as well as the ILS indicator for
the BC-733/ARN-5 pair)

> Me too.  The BC-733 (RC-103) and the AN/ARN-5* are
both controlled from the BC-732 control box, which is
pretty easy to find.  For late WWII-era, I'd suggest
finding the three-channel R-89/ARN-5A glide slope
receiver.  

I can get an R-54 or an R-89 so I'm set either way.  I
would hate to think about having to fabricate mounts
though.  That would not be pleasant at all.

> You'll want to find the AS-27/ARN-5 combined
localizer/glide slope receiver antenna.  They are not
too common, but not too rare either.

I haven't seen one for a while but I haven't nosed
around some of the bone yards that might have
something like that here.  (The keyword here is
"might".  I'm thinking the ones associated with the
operations still flying C-45s and C-47s here.)

> The receivers use a two-conductor twin-ax cable and
connectors that may be hard to find.  

Well, Robert has spoken up that he has the connectors
and ... well, wasn't that the same twinax that went to
the two-conductor connectors on the R-390 (or some
receiver of that ilk)?  If I remember right, it was 93
ohm and I'm sure I've seen that somewhere.  (Where is
another question! <G>) 

> The mountings are rare.  I'm still looking for a
mount for the BC-732 and BC-733.

Know any good fabricators? <G>

> I commend your interest in these nav sets.  

AS I said earlier, I have a personal interest in it.  

What would be cool would be the entire set - what we
discussed above plus the more mundane bits - airspeed,
altimeter, vertical speed, compasses (gyro and
magnetic), artificial horizon etc ... all working and
in an instrument panel - say the driver's side of a
B-25's or something.  Or capable of working.  Not
necessarily airworthy but good enough that when power
is applied, the gyros spin up and stabilize as they
should.  I'll worry about how to make the rest look
good some other time. 

Best regards,

Michael, K3MXO


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