[Milsurplus] APN-1 and other toys

[Mike Morrow]

Michael Tauson wrote

>Next, what indicator was used with the BC-733
>localizer receiver & the ARN-5 glide slope receiver? 
>Also, were they coupled to an autopilot?

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.

>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.  You get a hint of that because the AN/ARN-7 receiver is the R-5, while the AN/ARN-7 is the R-101.  In the JAN system, *usually* the individual component numbering sequence is a better indication of precedence than is the system numbering sequence.  The AN/ARN-7 was a late-WWII ADF, the best of the WWII airborne direction finders.

The MN-26 is not an ADF unless modified (MN-31).  It's actually easier to find *all* the components and connectors and mounts and loop RF cable for the SCR-269 or AN/ARN-7 than it is for the MN-26.

>Likewise, a marker receiver won't be a problem though
>the indicator(s) may be.

Of the many WWII-vintage marker beacon (MB) receivers, the BC-1333 is likely the best and is pretty common in new condition.  The MB indicator used by WWII-era MB receivers was a simple 28 vdc indicator lamp assembly.  The MB receiver energized the lamp at various rates as determined by MB transmitter keying to indicate which marker was being flown over.  The three-lamp system came after the war.

>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.  These were progressively modified for more channels up to the AN/ARN-5D after the war.

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.

The receivers use a two-conductor twin-ax cable and connectors that may be hard to find.  The mountings are rare.  I'm still looking for a mount for the BC-732 and BC-733.

I commend your interest in these nav sets.  The USAAF SCS-51 ILS stuff in particular seems not to spark much interest, even though it was a very important development, far better than the USN's adaption of the old pre-war Air-Track ILS (the ZA).  The SCS-51 is in every important particular the same system used worldwide today.

73,
Mike / KK5F